Category Archives: science

If at first you don’t succeed . . . statistical manipulation might help

Anti-fluoride campaigners are promoting yet another new study they claim shows community water fluoridation lowers children’s IQ. For example, the Fluoride Free NZ (FFNZ) press release Ground Breaking Study – Fluoridated Water Lowers Kid’s IQs which claims the study confirms“our worst fears, linking exposure to fluoridated water during pregnancy to lowered IQ for the developing child.”

Yet the study itself shows no significant difference in children whose mothers lived in fluoridated or unfluoridated areas during pregnancy. Here is the relevant data from Table 1 in the paper:

Mean IQ of children whose mothers drank fluoridated or unfluoridated water during pregnancy (SD =  11.9 – 14.7)

Nonfluoridated Fluoridated
All children 108.07 108.21
Boys 106.31 104.78
Girls 109.86 111.47

The differences between fluoridated and nonfluoridated are not statistically significant.

The paper has just been published and is:

Green, R., Lanphear, B., Hornung, R., Flora, D., Martinez-Mier, E. A., Neufeld, R., … Till, C. (2019). Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada. JAMA Pediatrics, 1–9.

Surprisingly the authors do not discuss the data in the table above. Its as if the data didn’t exist, despite being given in their Table 1. I find this surprising because their discussion is aimed at finding a difference – specifically, a decrease in child IQ due to fluoridation – and surely these mean values must be relevant. Were the authors embarrassed by these figures because they did not show the effect they wanted?

So how did they manage to find an effect they could attribute to fluoride, or fluoridation, despite the mean values above? They basically resort to statistical manipulation – and this has opened up an intense controversy about the paper.

An unprecedented “Editor’s Note”

The journal editor, Dimitri A. Christakis, published a note alongside the paper (see Decision to Publish Study on Maternal Fluoride Exposure During Pregnancy), together with a piece in the Opinion section by David C. Bellinger (see Is Fluoride Potentially Neurotoxic?). This opinion piece is described as an editorial although Bellinger is not an editor of the journal or on the Editorial Board.

This is, in my experience, completely unprecedented. Editor’s don’t comment on the quality of papers or the refereeing process and I can only conclude that within the journal editorial board and those who reviewed the paper there were sharp differences about its quality and whether it should be published. While an editorial may sometimes bring attention to an article, in this case, it is likely that Bellinger was one of the reviewers of the paper and he is expressing his viewpoint on it and supports its publication.

Christakis writes “The decision to publish this article was not easy.” He goes on to imply the journal supports publication “regardless of how contentious the results may be.”  But surely there is no need to defend a good quality paper in this way just because the results may be “contentious.”

Interestingly, FFNZ interpreted the publication of the Editor’s note as making the publication of the paper more “impactful” not realising that the Note is probably not positive for the paper as it reveals controversy over the paper’s quality and whether it was worthy of publication. FFNZ also chose to describe Bellinger’s comments in his opinion piece as representing the views of the authors. However, it would be inappropriate for an editor to make such comments.

I think Bellinger has his own biases and preferences which lead him to advocate for papers like this. I commented on Bellinger’s role in the review of another paper promoting an anti-fluoride perspective in my articles Poor peer-review – a case study and Poor peer review – and its consequences.

A large amount of controversy

I am surprised at the degree of controversy around this paper – and it’s loudness. The fact that it started on the same day the paper was made public reveal various actors have had access to the paper and have been debating it for some time.  This could have been stoked by the unorthodox statistical analysis used and contradictions in the findings.

But it appears this controversy had gone far wider than the journal editors and reviewers of the paper because of the immediate reactions from anti-fluoride organisations like the Fluoride Action Network (see BREAKING: GOVERNMENT-FUNDED STUDY LINKS FLUORIDATED WATER DURING PREGNANCY TO LOWER IQS IN OFFSPRING), some leading Newspapers,  professional bodies (see AADR Comment on Effect of Fluoride Exposure on Children’s IQ Study) and the UK Science Media Centre which published a reaction from experts article (see expert reaction to study looking at maternal exposure to fluoride and IQ in children).

This suggests to me a large degree of lobbying. Not only from activists and anti-fluoride scientists or reviewers. But also from authors and their institute. I am not really surprised as I have often seen how politics, activism, commercial interests, and scientific ambitions will coordinate in these situations.

How to discover an effect from a nonsignificant difference

So how do we get from the data in the table above – showing no statistically significant difference between fluoridated and unfluoridated areas – to a situation where the authors (who don’t refer to that data in their discussion) say:

“higher levels of fluoride exposure during pregnancy were associated with lower IQ scores in children measured at age 3 to 4 years. These findings were observed at fluoride levels typically found in white North American women. This indicates the possible need to reduce fluoride intake during pregnancy.”

In their press releases and statements to media, where they are not constrained by a journal’s need for evidence and objectivity, they come out even more vocally against community water fluoridation.

Well, it appears to me, by statistical manipulation. One of the Science Media experts referred to above, Prof Thom Baguley, wrote:

“First, the claim that maternal fluoride exposure is associated with a decrease in IQ of children is false. This finding was non-significant (but not reported in the abstract). They did observe a decrease for male children and a slight increase in IQ (but non-significant) for girls. This is an example of subgroup analysis – which is frowned upon in these kinds of studies because it is nearly always possible to identify some subgroup which shows an effect if the data are noisy. Here the data are very noisy.”

It appears the authors found a significant effect of child sex on IQ so made a decision to do a subgroup analysis – of boys and girls – and this produced a significant association of IQ with maternal urinary fluoride for the boys. This resort to subgroup analysis may have, in itself, produced a misleading significant relationship.

Adam Krutchen, Biostatistics PhD student at the University of Pittsburgh, also illustrates how the relationship with child sex has confused the analysis. He comments on the data that he managed to extract from the paper’s Figure 3:

“There were drastic sex-specific IQ differences in the children, which is of course strange. We shouldn’t expect anything like that to happen. This difference is very significant. There’s also some outlier extremely low IQ values among the male children.”

He is saying that his regression analysis showed a strong effect of child sex on IQ. This is quite irrespective of maternal urinary F or drinking water F. However, once that effect of child sex is taken into account he found no relationship of child IQ with maternal urinary F. He says:

“with such a significant effect of sex on IQ, does fluoride have any remaining relationship? The answer is a resounding no in the digitized data.”

It appears that including child sex difference in the regression analysis produces the finding that there is no significant relationship of fluoride to child IQ after taking into account the significant relationship of IQ with child sex. But when the data is divided into subgroups and analysed separately (a technique statisticians “frown on” “because it is nearly always possible to identify some subgroup which shows an effect if the data are noisy”) a significant relationship of IQ with maternal urinary fluoride can be produced for boys (but not girls).

Interestingly, a second part of the Green et al., (2019) study investigated a relationship of child IQ with unverified estimated fluoride intake by the pregnant mothers. The estimation method was not verified so may be questionable). No sex difference appeared in that data set.

How strong are the reported relationships

Perhaps it is not necessary to go any further. Perhaps the data for mean IQ in the table above is sufficient to show there is no effect of fluoride on IQ. Or perhaps the critique of the analysis of subgroups used is sufficient to make the reported conclusions suspect.

However, perhaps a comment on the weakness of the relationships reported by Green et al is useful – if only because I took the trouble to digitally extract the data from the figures in the paper and do my own regression analyses on the data.

Of course, digital extraction does not get all the data – even if only because the points may merge. In this case, I managed to extract 410 data points from Figure 3A which showed the relationships of child IQ with the maternal urinary F concentrations during pregnancy. This is quite a bit smaller than the 512 data pairs the authors reported in their Table 1 and suggests to me they had not plotted all their data. However, the values for means and coefficients obtained by my own regression were very similar to those reported by Green et al., (2019).

The authors reported a significant (p=0.02) negative relationship of boy’s IQ with maternal urinary F. They do not discuss how strong that relationship is – although the wide scatter of data points in the figures suggest it is not strong. My regression analysis showed the relationship explained only 1.3% of the variance in IQ. I do not think that is worth much. With such low explanatory power, I think the authors overstate their conclusions.

I think this is another case of placing far too much reliance on p-values and ignoring other results of the statistical analysis. I discussed this in a previous article – see Anti-fluoride activists misrepresent a new kidney/liver study).

Conclusions

I think this paper has been overblown. It has problems with its statistical analyses as well as other limitations referred to in the paper. I do not think it should have been published in its present form – surely reviewers should have picked up on these problems. I can only conclude that intense arguments occurred within the journal’s editorial board and amongst reviewers – and most probably more widely amongst institutes and activist groups. In the end, the publication decision was most likely political.

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Anti-fluoride activists misrepresent a new kidney/liver study

Image Credit: Wild Rose College

A new study reporting the ranges of values for kidney and liver parameters in a healthy population is being actively misrepresented by anti-fluoride campaigners. The Fluoride Action Network’s (FAN) latest bulletin claims the study shows “that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents.”

The study shows nothing of the sort. How could it – individuals suffering liver or kidney disease were specifically excluded from the study population. The reported parameter values are all for healthy individuals.

Readers can check for themselves – there is a free download. The paper is:

Malin, A. J., Lesseur, C., Busgang, S. A., Curtin, P., Wright, R. O., & Sanders, A. P. (2019). Fluoride exposure and kidney and liver function among adolescents in the United States: NHANES, 2013–2016. Environment International,

It is important to understand what this study really found. Not only is it being misreported by anti-fluoride activists. The University (The Mount Sinai Hospital/Mount Sinai School of Medicine) press release also appears to attribute more to the study’s findings than is warranted. This is a common problem with university public relations departments. (Readers are warned – the press release includes the disclaimer:

“AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system”

Below I list some information on the study

This is not a study about kidney or liver disease

Individuals showing such disease were specifically excluded. The study reports values for kidney and liver parameters in “generally healthy” subjects. The authors make this very clear in the discussion saying:

“this study did not aim to determine whether fluoride exposure is associated with clinical decrements in kidney function among U.S. adolescents. Rather, this study aimed to examine subclinical changes in kidney or liver parameters associated with fluoride exposure among a generally healthy population. For example, the lowest GFR estimated in this study was 84 mL/min/1.73m2, and therefore none were below the<75 mL/min/1.73m2 value considered reflective of
abnormal kidney function. Future prospective studies including participants with and without kidney disease are needed to assess clinical changes in kidney or liver function.”

So, this study just could not have identified factors causing kidney and liver disease, let alone confidently attribute a cause to the disease. So we can reject the anti-fluoride activist’s claims and their misrepresentation of the study results.

But why all this fuss about fluoride?

Because the authors have a preoccupation with fluoride they used statistical analyses to see if they could find any association between drinking water fluoride or blood plasma fluoride and the measured kidney and liver parameters. They did find a small number of very weak associations.

They do not support the claims made by anti-fluoride activists so details of their results and a critique of their results are irrelevant to the main arguments. But I do have a hangup about the way statistical analyses are used, and the way they are over-interpreted to support pet biases so will discuss their data below.

Very few associations found

The study included nine kidney and liver function test parameters. Only one of these (Blood Urea Nitrogen [BUN]) had a statistically significant relationship with water fluoride (Uncorrected p <0.001) – see figure below.

The relationship of BUN with blood plasma F was also statistically significant (Uncorrected p <0.001) – see figure below.

The Standard Reference Range of BUN for this adolescent population is 6–23 mg/dL. Only a few data points are outside that range and they mainly occur for low water F or plasma F concentrations.

The authors also reported statistically significant associations of estimated glomerular filtration rate (eGFR) and Serum uric acid (SUA) with blood plasma F. However, once adjustments were made for plasma cotinine levels (a biomarker of tobacco smoke exposure) associations were not statistically significant (uncorrected p=0.18 for eGFR) or only “marginally” statistically significant (uncorrected p=0.06 for SUA).

In effect, statistically significant associations with either water F or plasma F occurred for only one. It is not credible for FAN to use these associations as indicators “that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents.”

Reported associations may be “a pure act of will”

The authors appear to place a lot of reliance, in my opinion far too much reliance, of p values as somehow providing a causal mechanism behind the reported associations. This reliance has been strongly criticised by statisticians. Recently Briggs (2019) (Everything Wrong with P-Values Under One Roof) concluded:

“P-values should not be used. They have no justification under frequentist theory; they are pure acts of will. Arguments justifying p-values are fallacious. P-values are not used to make all decisions about a model, where in some cases judgment overrules p-values. There is no justification for this in frequentist theory. Hypothesis testing cannot identify cause. Models based on p-values are almost never verified against reality. P-values are never unique. They cause models to appear more real than reality.”

He goes on to elaborate:

“a small p-value has no bearing on any hypothesis . . . Making a decision about a parameter or data because the p-value takes any particular value is thus always fallacious . . . . Decisions made by researchers are often likely correct because experimenters are good at controlling their experiments, . . . . . ., but if the final decision is dependent on a p-value it is reached by a fallacy. It becomes a pure act of will.”

I believe Malin et al., (2019) place too much reliance on the p values they obtained and should have provided more complete results from the statistical analyses. Citing and relying on p values alone is, I believe, a major deficiency in this paper.

To their credit, while not providing full statistical analysis results the authors did display individual data points in their figures 1 and 2. This enables careful readers to make some judgments about the statistical analyses which would not be possible if the figures had not been provided.

Problems with outliers

The figures show a small number of outlying data points with some of the parameters. One has to be very careful that any association found only has a low p-value because of the influence (or leverage) of these outliers. The figures above for the BUN parameter illustrate the problem – particularly for water F where 2 data point greater than 6 mg/L clearly have a lot of influence.

This problem should stand out to any informed reader of the paper. The authors claim “Cook’s distance estimates were used to test for influential data points; none were identified.” However, this does not seem credible (particularly for Water F) so it is understandable that I should ask to see the results of these estimates so I can make up my own mind. They were not provided.

The associations were extremely weak

There is a huge scatter in the data points obvious in the figures above. This tells us that the reported associations can explain only a small amount of the variance. This is one reason why p-values alone can be misleading. A low p-value for an association (or fitted line) explaining only a few percent of the variance is meaningless. Concentration on such associations means that more important ones (explaining more of the variance) may be ignored. It also ignores the fact that the risk-modifying factor (in this case water F or plasma F) may simply be acting as proxies for more important factors (see Perrott 2018 for an example of this).

Malin et al., (219) should have provided more complete statistical analyses results to help readers judge the strength of the reported association. however, the figures themselves enable us to conclude the associations are very weak.

It is misleading to use the statistical result predictively

Malin et al., (2019) appear to “predict” the effect of fluoride on liver and kidney parameters, particularly BUN. They write in their abstract:

“A 1 mg/L increase in water fluoride was associated with a 0.93 mg/dL lower blood urea nitrogen concentration (95% CI: −1.44, −0.42; p=0.007)”

And

“1 μmol/L increase in plasma fluoride was associated with . . . . . a 1.29 mg/dL lower blood urea nitrogen concentration (95%CI: −1.87, −0.70; p < 0.001).”

But consider going from 0 to 1 mg/L in the image above for water F. The fitted line suggests that BUN would drop from about 11 to about 10 mg/dL. Taking the 95% CI interval into account the line “predicts” a value in the range of about 9.56 to 10.58 mg/dL. But only a small number of the points scattered at about 1 mg/L F have values in that range.

[Yes, I know. The authors only refer to associations, but reports of this work in the alternative health media are using these statements as predictions and that is how activists are suing the information.]

All that the best fit line can predict are values which fit the line. As the association represented by the best-fit line explains only a very small percentage of the variance (despite the small p-value) these “predictions” are meaningless. Unfortunately, the authors do not make this clear in their paper and this deficiency only contributes to the ability of anti-fluoride activists to misrepresent the findings.

Conclusions

Anti-fluoride activists are misrepresenting the finding reported in this paper. The authors themselves stress that their study was not designed to determine if fluoride exposure is associated with, or causes, declines in kidney or liver health. The FAN claim that the study shows“that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents” is completely incorrect.

That is all we need to know regarding the way activists are misrepresenting the study. However, a closer look at the data suggests that the associations with fluoride for healthy individuals reported in the paper are extremely weak.

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Chemical watchdog confirms suppressed report but justifies the suppression

Director-General of OPCW Fernando Arias Gonzales admits Douma engineers report was legit and he was part of the FFM – but attempts to justify suppression of the report.

France 24 reports that the head of the Organisation for the Prohibition of Chemical Weapons (OPCW) “has ordered a probe into the leak of an internal paper which queried the body’s findings into a 2018 attack in the Syrian town of Douma” (see Chemical weapons body probes leaked document on Syrian attack). This is yet another confirmation of the authenticity of the leaked document I discussed in Does international chemical watchdog cherry-pick evidence to confirm a bias? Recent documents form the OPCW also confirm that Ian Henderson, the head of the engineering subteam that prepared the suppressed document, was employed by the OPCW (see Remarks of the Director-General at the Briefing for States Parties on Syrian Arab Republic: Update on IIT-FFM-SSRC-DAT).

This should put to rest claims made by some corporate media journalists that the leaked document was fake and manufactured to discredit OPCW findings. Even so, these same journalists are not exactly rushing to repor the issue.

I guess no one who has worked for a large organisation, whether corporate or state owned, can be surprised at the way the OPCW is reacting to the leaked document. Or surprised that an important analysis was supressed leading to questions about the reliability of the final reports.

But the fact this is an international organisation bearing responsibility for monitory and eliminating a whole class of dangerous weapons makes the behaviour very serious. Even worse, the apparent bias in the final report about an incident which supposedly lead to the deaths of so many civilians raises questions about the ethical behaviour of the OPCW. It is very likely a war crime was committed and the OPCW has not only failed in its role to objectively elucidate the evidence of this crime but actively worked to prevent attributing blame to the likely instigators of the crime. Instead the OPCW appears to have succumbed to political pressure from NATO-aligned countries to blame an innocent party.

Alleged victims of chemcial attack in Douma, Syria. Who was responsible for these deaths? Image credit: New York Times – Most Chemical Attacks in Syria Get Little Attention. Here Are 34 Confirmed Cases.

Given the seriousness of this matter, it is pleasing to see that the media is starting to provide some coverage of the document suppression – although very belatedly and in a very limited matter in the case of the corporate mainstream media. I hope the truth comes out and I hope, as a result, steps are taken to reform OPCW procedures to limit this sort of political interference.

However, in this post, I will just deal with an attitude expressed by the OPCW which displays a very unscientific attitude to their work. The idea that evidence should be selected to support a conclusion – rather than the conclusion be based on all the evidence.

Director-General of OPCW admits the legitimacy of engineers’ report

The video above shows Fernando Arias Gonzales, the Director-General of OPCW, admitting to the legitimacy of the engineers’ report and attempting to justify the fact its findings were excluded from the final report. I described the findings of the suppressed report in Does international chemical watchdog cherry-pick evidence to confirm a bias?

Briefly, whereas the final OPCW report provided evidence for the finding that the chlorine cylinders had been dropped from the air, the suppressed engineers’ report found it far more probable that the cylinders had been placed manually.  Considerations of the sizes of the ceiling holes, the possible velocities of the cylinders and damage to them, and surrounding damage were considered in the suppressed report.

Whereas other external engineers were later consulted by the OPCW and provided arguments justifying air-delivery I would expect an objective report would include all the analyses and information available. On those grounds alone the Director-General’s arguments for suppression are very suspect and do nothing to alleviate the subsequent loss of credibility of his organisation.

But to me it is worse – his comments are scientifically unethical.

“But sometimes it does not fit to the conclusion”

How can a report be considered credible if evidence contradicting its conclusion is omitted? Fernando Arias Gonzales does nothing to preserve the integrity of his organisation when he says of evidence – “But sometimes it does not fit to the conclusion.”

His statement implies that in this case the writers of the report started with a conclusion and then selected only that evidence which could support their pet conclusion.

That is scientifically unethical and displays probable political pressure.

Hiding behind possible attribution

In a formal statement from the OPCW the Director-General provides yet another justification for the report’s suppression:

“The document produced by this staff member pointed at possible attribution, which is outside of the mandate of the FFM with regard to the formulation of its findings. Therefore, I instructed that, beyond the copy that would exclusively be kept by the FFM, the staff member be advised to submit his assessment to the IIT*, which he did, so that this document could later be used by the IIT.”

But this is just incredulous. The final report presented only the evidence supporting air delivery of the two chlorine cylinders. The suppressed report presented evidence which did not support air delivery but was consistent with the cylinders being placed manually.

Neither the engineer’s report nor the final report mentioned any attribution – although of course attribution could be inferred. By arguing for air-delivery the final report can be seen as possible laying the blame on the Syrian state forces which used helicopters in the area.  Manual placement provides for possible attribution to the jihadist forces and a staged event. But neither of these are stated directly and it is disingenuous for the Director-General to claim, the suppressed report “pointed at possible attribution” but the final report didn’t.

Really, the Director-General’s statement has only dug a deeper hole and further reduced the credibility of the origination and its past and future reports.

*IIT –Investigation and Identification Team. This has been set up by the OPCW Secretariat to identify “the perpetrators of the use of chemical weapons in the Syrian Arab Republic.” However, it does not have full support from OPCW members and its establishment is controversial.

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Does international chemical watchdog cherry-pick evidence to confirm a bias?

Organisation for Prohibition of Chemical Weapons headquarters in The Hague. Image credit: Prensa Latina Ready Syria to Cooperate with Organization Against Chemical Weapons

Multinational bodies, like the Organisation for Prohibition of Chemical Weapons (OPCW) usually have authority and appearance of objectivity because of their international and representative nature. But I have been disappointed with some of the OPCW reports because they relied on hearsay and appeared to suffer bias. They also usually lack transparency and suffer from lack of data. I have discussed some of this in my articles Another shonky OPCW chemical incident report on Syria and OPCW on Salisbury poisoning – one step forward, two back?

It is probably inevitable that a theoretically objective  or non-partisan organisation will, in practice, be influenced by political and geopolitical interests. Even so, I am shocked to discover that The OPCW may have resorted to cherry-picking evidence for their Final Report of the OPCW Fact-Finding Mission (FFM) on the alleged chemical attack in Douma on 7 April 2018, released on 1 March 2019.

Paul McKeigue, David Miller and Piers Robinson who are members of Working Group on Syria, Propaganda and Media, revealed the cherry picking in their report Assessment by the engineering sub-team of the OPCW Fact-Finding Mission investigating the alleged chemical attack in Douma in April 2018.

OPCW sidelines its own fact-finding engineers

Specifically the Final OPCW report ignored the findings of their own Fact-Finding Mission (FFM) Engineering Subteam that was part of the original investigation on the ground. Instead, the OPCW later contracted unidentified experts who provided the engineering analyses included in the final report.

These unidentified experts produced a different conclusion to that reached by the FFM engineering subteam as described in a leaked dcouyment from the subgroup (Engineering-assessment-of-two-cylinders-observed-at-the-Douma-incident-27-February-2019-1). That, in itself, is not surprising – consider how in criminal cases prosecutors and defence can produce their own experts to make completely opposite arguments.  But the OPCW should have at the very least acknowledged the two different conclusions from the two different groups. They should also have given more weight to the conclusions of the own subteam who were involved in the initial investigations rather than the contracted experts who relied only on second-hand data (and were possibly given a more limited mandate).

I wrote about the interim report on this alleged chemical attack and its misrepresentation by corporate media in my article Blatant misreporting of latest OPCW report on chemical weapons in Syria. The interim report considered the allegation that a chemical weapon had been used and concluded:

“No organophosphorus nerve agents or their degradation products were detected, either in the environmental samples or in plasma samples from the alleged casualties.”

The notorious chlorine gas cylinders

However, it left open the possibility that chlorine gas had been used and this was considered in the final report which considered the two chlorine gas cylinders found at the site of the alleged chemical attack.

The two engineering reports relate to these chlorine gas cylinders. Whereas the original Fact-Finding Mission engineering subteam concluded that the chlorine gas cylinders had most probably been manually placed at the scene the anonymous experts later contracted by the OPCW appear to favour an explanation involving delivery by an aircraft.

From the report of the engineering subteam of the fact-finding mission – (Engineering-assessment-of-two-cylinders-observed-at-the-Douma-incident-27-February-2019-1)

The arguments and conclusions of the anonyous contracted enegineering experts are contained in the final report – Report of the Fact-Finding Mission Regarding the Incident of Alleged use of Toxic Chemicals as a Weapon in Douma, Syrian Arab Republic, on 7 April 2018.

LOCATION 2

The above propaganda video from the White Helmets (allied with the jihadists in Douma) illustrates the position of this gas cylinder on a roof adjacent to a crater.

The anonymous contracted experts concluded the cylinder had been dropped onto the roof with sufficent kinetic energy to create the crater but not penetrate the roof. However the OPCW FFM subteam concluded from their modelling:

“that the alleged impact event or events leading to observed vessel deformation and concrete damage were not compatible.

A criss-cross pattern on the paintwork of the cylinder body, that had been attributed by some observers to the cylinder falling through the wire mesh, was inconsistent with the near-vertical angle of incidence that would have been required to create the crater.

Experts consulted to assess the appearance of the crater took the view that it was more consistent with a blast (from a mortar round or rocket artillery) than with an impact from the falling object. Similar craters were present in concrete slabs on top of nearby buildings.”

They concluded that the cylinder had more probably been manually placed in the location rather than dropped from an aircraft.

LOCATION 4

This cylinder has always appeared strange, lying on a bed in a room that was relatively undamaged.

The anonymous contracted experts concluded (or maybe assumed) the cylinder had been dropped from the air and come through the ceiling to land on the floor where it subsequently bounced onto the bed (see image below from the OPCW final report).

However the FFM engineering subteam concluded from their analyses and modelling:

“that the cylinder with intact valve and fins attached could not have fitted through the hole in the roof:

it was not possible to establish a set of circumstances where the post-deformation cylinder could fit through the crater with the valve still intact (whether or not an end-cap was assumed to have been fitted at the front end of the cylinder), and the fins deformed in the manner observed.”

Conclusions

I can understand how different assessment teams can come to different conclusions and it could well be that the anonymous contracted experts were asked to assume that the cylinders had been dropped and to model possible trajectories and dmagge. In contrast the intial FFM engineering team considered alternative hypotheses as well as air-dropped cylinders and specifically proposed the alternatives in their report.

Such modelling and conlcusions can’t help but involve a degree of speculation so it does not concern me that different conclusions were drawn. But I am very concerned that the OPCW final report ignored the findings of their own FFM engineering subteam. This indicates a degree of bias which should be unacceptable for such an international body.

The authors from the Working Group on Syria, Propaganda and Media go as far as describing the issue as the hijacking of OPCW concluding:

“The new information we have removes all doubt that the organization has been hijacked at the top by France, UK and the US. We have no doubt that most OPCW staff continue to do their jobs professionally, and that some who are uneasy about the direction that the organization has taken nevertheless wish to protect its reputation. However what is at stake here is more than the reputation of the organization: the staged incident in Douma provoked a missile attack by the US, UK and France on 14 April 2018 that could have led to all-out war.

The cover-up of evidence that the Douma incident was staged is not merely misconduct. As the staging of the Douma incident entailed mass murder of civilians, those in OPCW who have suppressed the evidence of staging are, unwittingly or otherwise, colluding with mass murder.”

Other commentary on the OPCW FFM Engineering subteam report:

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Preempting the annual misrepresentation of NZ dental health data by anti-fluoride activists

Dental therapist Heather Dalton examines an Avondale College student in Auckland in 2010. Image credit: Te Ara: The Encyclopedia of NZ.

The latest NZ school dental service data again confirms that community water fluoridation is effective.  The data show benefits of up to about 30% improvement in oral health. But, anti-fluoride activists will, once again,  reject this evidence and instead cherry-pick the data to support their claims.

The NZ Ministry of Health (MoH) has posted the latest summary of child dental health collected by the dental health service. So it is time for local anti-fluoride activists to indulge in their annual activity of cherry-picking and misrepresentation to claim the data “proves” community water fluoridation (CWF) is ineffective (see my comment on last year’s misrepresentation – Anti-fluoridationists misrepresent New Zealand dental data – an annual event).

I haven’t seen this year’s expected press release from Fluoride Free NZ. I may have missed it or perhaps they haven’t got their A into G yet (although there is a bit of notice on their Facebook page). Nevertheless, I will post here my annual analysis of the data.

My comments are much the same as last year – the data has not really changed. But first an explanation of how the data should be used

Nature of the MoH dental health data

The published spreadsheets are simply records of dental health (% caries free and mean Decayed, Missing and Filled Teeth (DMFT and dmft) for 5-year-olds and year 8  children. There has been no selection of children to give representative data. Distortion due to ethnic and socioeconomic factors has not been taken into account.

Data are presented for all children – (Total), Maori, Pacific Island and “Other.” I have previously explained that the Total data is distorted by ethnic factors – different ethnic groups have differences in oral health, irrespective of fluoridation. In particular, the predominance of Pacific Island children in fluoridated areas distort the “Total” data – 85% live in fluoridated areas. Pacific Island children comprise about 15.1% of children in fluoridated areas but only about 3.2% of children in non-fluoridated areas.

Because Pacific Island children generally have poorer health they increase the value of dmft/DMFT and lower the value of caries-free % in the fluoridated areas in the Total figures. Therefore the “Other” figures are more reliable than the “Total” figures for interpretation.

The 2017 data

You can download the two spreadsheets, and the spreadsheets for earlier years, from the MoH website – Age 5 and Year 8 oral health data from the Community Oral Health Service). I will just give the overall New Zealand data for Māori and “Other” (this is all except Māori and Pacific Island).

As explained above the “Total” data is misleading because of ethnic effects and the data for Pacific Island is poor because only a small number resided in non-fluoridated areas.

5-Year Old Children

Clearly, the overall data suggest a benefit of fluoridation to Maōri and “other” children – about 14% for “Other” and 25% for Māori children (using the data for mean dmft).

Year 8 Children


Again the data suggests that fluoridation has been beneficial to Māori and “Other” children. The DMFT data suggest a benefit of about 30.5% for Māori and 26% for “Other” children.  Even the %Caries free data indicates benefits of about 16% and 11% for Māori and “Other” children respectively.

Changes over time

It’s worth considering more than one year. This overcomes, to some extent, variations in the data. It may also be helpful in assessing if the effectiveness of CWF is changing.

However, there is a proviso. Let’s not forget this is simply raw data from the school dental service. While I have corrected for ethnic differences I have no way of correcting for other differences. Socioeconomic effects may change over time. Another important factor is that, at least in some regions, dental health authorities are targeting children form non-fluoridated areas with extra treatments like fluoride tooth varnishes. Ideally, a controlled experiment would take all these factors into account.

I will just take one example – the DMFT data for year 8 children.

The table shows the mean values of %Caries free and DMFT of year 8 children over the periods 2005-2017 and 2013-2017.

Year 8 Children Māori “Other”

%Caries Free

Mean 2005-2017 24.2 13.4
Mean 2013-2017 15.6 8.8

MDFT

Mean 2005-2017 31.3 24.7
Mean 2013-2017 30.1 22.2

This data shows that the oral health of both Māori and “Other” children have improved over time irrespective fluoridation. But there is still a difference between fluoidated and unfluodiated areas indicating fluoridation is having a benefit over and above other factors contributiong to oral health improvement.

The differences due to fluoridation seem to be diminishing. However, my comments above are relevant here. This could be due to extra fluoride treatments targeting children from non-fluoridated areas.

It’s obviously a factor for health authorities to consider but limitations in this data should be kept in mind and other sources of information also considered.

Conclusions

Once again the MoH school dental service data show benefits from CWF. But don’t expect anti-fluoride activists to accept this. I expect they will indulge in their usual cherry-picking of the data to confirm their biases.

Fluoridation: Another study shows stopping fluoridation bad for child tooth decay

Stopping community water fluoridation in Alaska’s capital city, Juneau, caused an increase in child tooth decay

In the last week, Windsor in Ontario, Canada, voted to reinstate community water fluoridation (CWF) 5 years after it was stopped because of opposition. This time the City Council was swayed by the Windsor-Essex County Health Unit’s Oral Health 2018 Report which found the percentage of children with tooth decay or requiring urgent care increased by 51 per cent since fluoridation had stopped.

Now a new study reports similar increases in child tooth decay after stopping CWF in the Alaskan capital, Juneau. This paper reports the study results for Juneau:

Meyer, J., Maragaritis, V., & Mendelshon, A. (2018). Consequences of community water fluoridation cessation for Medicaid-eligible children and adolescents in Juneau, Alaska. BMC Oral Health, 18:215

Juneau – an ideal community for the study

Juneau maintains all the modern conveniences and standards expected of a capital city but has little in-and-out migration or travel from neighboring countries as it is accessible only by plane or sea. This reduces confounding effects due to population changes, only about 0.006% per year during the study period.

Use of fluoridated toothpaste is widespread and CWF was available to 96% of residents before it was stopped in January 2007.

The researchers compared child oral health data in 2003 (when children were exposed to optimum levels of fluoride: 0.7 – 1.2 mg/L) with that in 2012, 6 years after CWF ceased. During those six years, exposure to fluoride was suboptimum: <0.065 mg/L.

The data used for the study was from Medicaid dental claims records. This means the study population was made up of residents living at near poverty conditions. This limited confounding effects from higher-income groups.

Cessation of CWF resulted in increased child tooth decay

The findings were clear and statistically significant. The number of caries-related dental procedures increased after cessation of CWF.

For all children and adolescents (ages 0 – 18 years) the number of procedures increased by 16%. But binary logistic results indicated “the odds of a child or adolescent undergoing a dental caries procedure in 2003 was 25.2% less than that of a child or adolescent in the suboptimal CWF group.”

The effects of CWF were even greater for children aged 0 – 6 years who had never experienced the advantages of exposure optimum fluoride levels. The number of caries-related dental procedures in this group increased by 63%. However,  binary logistic results indicated “the odds of undergoing dental caries procedures under optimal CWF conditions was 51% less than that for a child of the same age in 2012 under suboptimal conditions.”

CWF cessation increased dental treatment costs

The researchers obtained dental costs from the Medicaid dental claims records so were able to make estimates of the effects of CWF on the financial costs to the community. After adjusting for inflation this data showed that the increased annual cost per person of ages 0 – 18 years due toi cessation of CWF increased by $162, a 47% increase. The corresponding increase for children 0 – 6 years was %303, a 111% increase.

Conclusions

While this study had several advantages over similar studies because of reduced confounding effects due to migration and socioeconomic factors this may also be seen as a limitation when trying o extend to findings to more socially heterogeneous communities. However the authors conclude it does provide stong evidence supporting:

“current evidence that even in modern conditions with widely available fluoride toothpaste, rinses, and professionally applied prophylaxis, CWF is associated with population benefits, including cost effectiveness and caries prevention.”

They also conclude from their results that:

“CWF cessation promoted a marked increase in the number of caries-related procedures and treatment costs for Medicaid-eligible children and adolescents aged 0–18 years. Additionally, the results indicated that children in the younger age group cohorts underwent more dental caries procedures than the older age group cohorts, who had benefited from early childhood exposure to optimal CWF.”

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Protection of teeth by fluoride confirmed – yet again

 

Fluoride protects teeth from the attack of acid and microbes. Figure from Faidt et al., (2018)

The protective role of fluoride in teeth has been confirmed, yet again. A new study nicely demonstrates how incorporation of even a small amount of fluoride into the surface layer of teeth protects them from the acid attack which leads to tooth decay.

Researchers measured the ablation, or loss of surface material from hydroxyapatite before fluoridation and after fluoridation. It showed a clear difference due to inhibition of ablation by fluoride.

The research findings are published in:

Faidt, T., Friedrichs, A., Grandthyll, S., Spengler, C., Jacobs, K., & Müller, F. (2018). Effect of fluoride treatment on the acid-resistance of hydroxyapatite. Langmuir

Measuring ablation

Samples were etched with a sodium acetate buffer at pH 4.5 which simulated the effect of an acid attack on teeth resulting from the formation of acid when sugars are microbiologically decomposed in the mouth. The degree of ablation was measured using atomic force microscopy (AFM). Part of the sample surface was coated with a gold layer to prevent acid attack and give a reference surface.

Fluoridated surfaces, submerged for five minutes in a sodium acetate buffer at ph 6.0 cotnaining 500 mg/L of sodim fluoride, were compared with unfluoridated surfaces.

Results

Interestingly, the AFM height images showed there were two different areas of the hydroxyapatite surface when it came to ablation – a fast etching area and a slow etching area. The authors attributed this to the different orientations of crystallites in the hydroxyapatite sample. The image below is for an unfluoridated sample

Ablation of  fluoridated samples was quite different – no ablation occurred until after 330 seconds – the image below is for a fluoridated sample

The paper summarises the results for the fluoridated and unfluoridated surfaces and the different ablation rates due to crystallite orientation in this figure:

The crystallites that etched slowly (Z2) in the unfluoridated sample did not etch at all in the fluoridated sample. The more rapidly etching crystallites (Z1) did etch in the fluoridated sample but only after a delay.

The authors concluded that some of the fluoride in the surface layer of the fluoridated samples could eventually be removed by soaking in the acid buffer – but only after a delay. This was confirmed by an analysis of the surface concentrations of Ca, P, O and F using X-ray photoelectron spectroscopy (XPS) – see below:

Thickness of the fluoridated surface layer

The authors recall:

“In a former study, we revealed that the thickness of the HAp layer that can be loaded with fluoride is in the range of only a few nanometers (24, 25), even if loaded under optimal conditions (25). “

So – a very thin layer. One that some anti-fluoridation commenters claimed insufficient to give any protection. As the authors say

” the question arose whether such a thin layer would actually be capable of protecting the surface against acid attacks. “

But, their results definitely show that this thin layer does offer protection. I am sure critics will quickly point to the fact that the experimental study showed the removal of some of the fluoride after about 400 seconds. But this removal should be seen in the light of the dynamic system in the oral cavity where the pH of saliva is changing, dropping due to sugar decomposition and then rising again. The presence of fluoride, together with phosphate and calcium in saliva also leads to repair of areas where acid attack has occurred.

Conclusions

This experimental work confirms the protective role of fluoride in saliva for existing teeth – despite the fact that the fluoridated layer may be extremely thin – of the order of a few nanometers. While some of the fluoride in the surface layers is eventually removed the presence of fluoride in saliva helps replenish these layers and repair areas of acid attack.

The authors conclude their results provide:

“evidence that already thin and low concentrated fluoridated layers have a large effect on the acid resistance of HAp [hydroxyapatite]”

They combine these finding with results from a previous study of theirs showing fluoridation reduced adhesion forces of bacteria on hydroxyapatite (HAp) to finally conclude:

“the caries-preventive effect of fluoride is an interplay of at least two mechanisms: a reduction of the solubility and a reduction of the bacterial adhesion force.”

Hence the figure at the top of this article.

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Fluoridation and ADHD: A new round of statistical straw clutching

“To clutch at straws – the act of reaching for a solution no matter how irrational or inconsequential.” Source: Advanced Vocabulary for English Language Learners

Anti-fluoridation activists are promoting a number of new scientific papers they argue support their campaigns. But one has only to critically read these papers to see they are clutching at straws. Their promotion relies on an unsophisticated understanding of statistics and confirmation bias.

I will look at one paper here – that of Bashash et al., (2018) which reports an association between maternal prenatal urinary fluoride and prevalence of child ADHD.

The paper is:

Bashash, M., Marchand, M., Hu, H., Till, C., Martinez-Mier, E. A., Sanchez, B. N., … Téllez-Rojo, M. M. (2018). Prenatal fluoride exposure and attention deficit hyperactivity disorder (ADHD) symptoms in children at 6–12 years of age in Mexico City. Environment International, 121(August), 658–666.

I discussed an earlier paper  by these authors – Bashash et al., (2016) which reported an association between maternal neonatal IQ fluoride and child IQ – (also heavily promoted by anti-fluoride activists) in a number of articles:

Promotion of the new paper by anti-fluoride activists suffers from the same problems I pointed out for their promotion of the earlier paper. In particular it ignores the fact that the reported relationships (between maternal neonatal urinary fluoride and cognitive measure for children in Bashash et al., 2016, and prevalence of child  attention deficit hyperactivity disorder – ADHD – in Bashash et al., 2018) were very weak and explain only a very small amount of the variation. This raises the possibility that the reported weak relationships would disappear if significant risk-modifying factors were included in the statistical analyses.

Bashash, et al., (2018)

Whereas the earlier paper considered measures of cognitive deficits in the children the current paper considers various measurements related to ADHD prevalence among the children. These include parent rating scales (CRS-R). Three were ADHD-related scales from the Diagnostic and Statistical Manual of Mental Disorders (DSM) (Inattention Index, Hyperactivity-Impulsive Index and Total Index [inattentive and hyperactivity-impulse behaviours combined]). They also include several other indexes related to ADHD.

A number of computer-assisted indexes (CPT-II) were also determined.

Most indices were not significantly associated with maternal prenatal urinary fluoride. However, the authors reported statistically significant (p<0.05) relationships for indices of Cognitive Problems + Inattention, ADHD Index, DSM Inattention and DSM ADHD Total.

The data and the relationships were provided in graphical form – see figure below – taken from their Figure 2:

There is obviously a wide scatter of data points indicating that the observed relationships, although statistically significant, explain only a small part of the variation in the indices.

So, just how good are the relationships reported by Bashash et al., (2018) in explaining the variation in these ADHD-related indices? I checked this out by digitally extracting the data from the figures and using linear regression analysis.

Index

% Variance explained

Cognitive problems + Inattention 2.9%
ADHD Index 3.1%
DSM Inattention 3.6%
DSM ADHD Total 3.2%

In fact, these relationships are extremely weak – explaining only a few per cent of the observed variation in the ADHD related indices. This repeats the situation for the cognition-related indices reported on the Bashash et al., (2016) paper (see Maternal urinary fluoride/IQ study – an update).

The fact these relationships were so weak has two consequences:

  1. Drawing any conclusions that maternal neonatal fluoride intake influences child ADHD prevalence is not justified. There are obviously much more important factors involved that have not been considered in the statistical analysis.
  2. Inclusion of relevant risk-modifying factors in the statistical analysis will possibly remove any statistical significance of the relationship with maternal urinary fluoride.

Credible risk-modifying factors not considered

Bashash et al., (2108) do list a number of possible confounding factors they considered. These did not markedly influence their results. however, other important factors were not included.

Nutrition is an important factor. Malin et al., (2108) reported a signficant effect of nutrition on cognitive indices for a subsample of the mother-child pairs in this study (see A more convincing take on prenatal maternal dietary effects on child IQ).

Their statistical analyses show that nutrition could explain over 11% of the variation in child cognitive indices indicating that nutrition should have been included as a possible risk-modifying factor in the statistical analyses of Bashash et al., (2016) and Bashash et al., (2018). I can appreciate that nutrition data was not available for all the mother-child pairs considered in the Bashash et al., papers. However, I look forward to a new statistical analysis of the subset used by Malin et al., (2108) which includes prenatal maternal urinary fluoride as a risk-modifying factor and tests for relationships with child ADHD prevalence.

Could the reported weak relationship disappear?

Possibly. After all, it is very weak.

The problem is that urinary fluoride data could simply be a proxy for a more important risk-modifying factor. That is, urinary fluoride could be related to other risk modifying factors (eg. nutrition) so that the relationship with urinary fluoride could disappear when these other factors are included.

I illustrated this for a earlier reported relationship of child ADHD prevalence with extent of fluoridation in US states (see Perrott 2017 – Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)). In  that case the relationship was much better than those reported by Bashash et al., (2016) and Bashash et al., (2018) – explaining 24%, 22% and 31% of the variance in ADHD prevalence for the years 2003, 2007 and 2011 respectively. The relationships are illustrated in their figure:

Relationships between water fluoridation (%) and child ADHD prevalence for 20013 (red triangles), 2007 (blue diamonds) and 2011 (purple circles). Malin & Till (2105)

Yet, when other risk-modifying factors (particularly mean state elevation) not considered by Malin & Till (2015) were included in the regression analyses there was no statistically significant influence from fluoridation prevalence. In this case fluoridation prevalence was related to altitude and was simply acting as a proxy for altitude in the Malin & Till (2015) regression.

Conclusion

As the authors admit, this study:

“was not initially designed to study fluoride exposure and so we are missing some aspects of fluoride exposure assessments (e.g., detailed assessments of diet, water, etc.).”

However, they do say these “are now underway” so I look forward with interest to the publication of a more complete statistical analysis in the future.

There are other problems with the data (for example the paucity and nature of the urinary fluoride measurements) and these are the sort of issues inevitably confronting researchers wishing to explore existing data rather than design experimental protocols at the beginning.

Readers should therefore always be hesitant in their interpretations of the results and the credibility or faith that they put on the conclusions of such studies. The attitude should be: “that is interesting – now let’s design an experiment to test these hypothetical conclusions.”

The problem is confirmation bias – the willingness to give more credibility to the findings than is warranted. Scientists are only human and easily succumb to such biases in interpreting their own work. But this is even more true of political activists.

The reported relationships are weak. Important risk-modifying factors were probably not included in the statistical analyses. The observed relationships may simply mean that urinary fluoride is acting as a proxy for a more important risk-modifying factor (like nutrition) and the weak relationship may disappear when these are considered.

So scientific assessment of this study will be extremely hesitant – interpreting it, at best, as indicating need for more work and better designed research protocols.

But, of course, political activists will lap it up. It confirms their biases. Political activist organisations like the Fluoride Action Network are heavily promoting this paper – as they did with the earlier Bashash et al., (2016) paper.

But they are simply clutching at straws – as they often are when using science (or more correctly  misrepresenting and distorting the science) to support their political demands.

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Flight MH17 tragedy in Ukraine – new evidence

New evidence presented at Russian Ministry of Defence press conference, 17 September 2018.

In July 2014 the Malaysian Airline Flight MH17 was shot down over eastern Ukraine. All 283 passengers and 15 crew died. A Dutch-led international Joint Investigation Team (JIT) has been investigating the tragedy with the aim of determining criminal blame.

Update: Facebook took it upon themselves to censor my timeline and remove the Facebook post of my article. It seems their fact-checkers at the Atlantic Council have judged this information as “not following community standards”

Bit of a lesson there.

 

The JIT produced a preliminary report in 2016 (see But will it stand up in court?) and updated this with new evidence at a press conference last May 24. At the conference they revealed the serial number of the missile which shot down the plane and made a general appeal for people who might have information on this to come forward. At a Press Conference this week the Ministry of Defence (MOD) of the Russian Federation has responded with information from the manufacturer’s log books about this specific missile.

This appears to be the most concrete evidence to date which could be used to lay credible blame for the tragedy.

The JIT reveals serial numbers of the missile and appeals to the public for information about it.

While the JIT May 24 statement laid the blame on the Russian Federation, their evidence was rather subjective – relying on subjective interpretation of markings on vehicles in videos available online. “Open source” evidence. In contrast, the Russian MOD was specific and taken from archived information from the missile manufacturer.

In a way, this is rather unique because this information was understandably classified. Presumably, Russian officials have been active in the period between May and September locating the log books, interviewing relevant staff members from the time of production and going through the bureaucratic procedures required to declassify the material.

The new evidence

The video of the Russian MOD press conference above summarises three pieces of evidence the Russians have made available:

1: The most convincing evidence is the date of manufacture of the specific missile (December 1986) and its transport to the military unit where it was deployed. The records show it was deployed to a unit based near Lvov in the then Ukrainian Socialist Republic. It had never been returned to Russian territory.

I think that evidence is solid. The MOD spokesperson said the information has been passed onto the JIT and if they ask to inspect the archives they will be invited to Moscow to do so. He also made the point that the Russian side has asked the JIT to request the log books of the Ukrainian military unit which has been in possession of that missile and reveal its movements and location during July 2014.

2: Analysis of the video material the JIT had relied on to support their conclusion that the missile came from the Russian 53rd Anti Aircraft Missile Brigade based near Kursk in the Russian Federation. That video material had initially been compiled by Bellingcat, a suspect internet group now allied with NATO. The JIT conclusion relied on subjective tracking of markings on a BUK unit and its transporter and claimed to track it through its journey.

JIT open source video evidence supporting their conclusion that the BUK unit came from Russia

Russian experts have analysed these videos and shown problems with lighting and perspective indicating they have been faked. Something as simple as placing an image of a BUK unit into an existing video.

Their analysis seems credible, but obviously, this is the sort of thing which could be debated between experts in a court.

3: A recording of a telephone conversation made in 21016 where Ukrainian Armed Forces Col. Ruslan Grinchak refers to the tragedy in a way that implied it was caused by the Ukrainian armed forces. This person was in charge of airspace over the Donetsk region at the time of the tragedy.

This evidence relies on interpretation so is less convincing by itself.

Conclusion

The new evidence resulting from the discovery of the missile serial numbers by the JIT looks conclusive. As Russian Lieutenant General Nikolai Parshin told reporters the archives show:

“the missile was assembled on December 24, 1986, and delivered by rail to the military unit number 20/152, officially named the 223rd Air Defense Missile Brigade. It was deployed to the Ukrainian Soviet Socialist Republic’s Ternopol Region, which was part of the Subcarpathian Military District.”

Unless archive evidence in the possession of the Ukrainian armed forces can show that the missile was subsequently exported back to the Russian Federation there seems no doubt that Flight MH17 was shot down by a Ukrainian missile.

However, much more has to be done to apportion blame. There is still the possibility that this particular BUK unit was in the hands of the separatist forces in the Donetsk or Lugansk regions (although Dutch Intelligence reports at the time indicated any BUK units in the hands of separatists were not functioning -see Flight MH17 in Ukraine – what do intelligence services know?).

What is clear is that the ball is now back in the hands of the JIT, and more specifically, the Ukrainian armed forces. The JIT should now demand archived information on the locations, servicing and possession of this specific missile in the period between 2086 and July 2014.

Of course, as in other aspects of this investigation, the Ukrainian side may claim that records do not exist or have been destroyed. I do not think that is good enough and such lack of cooperation has already damaged the reputation and reliability of the JIT. Ukraine, as possibly one of the suspects, should never have been given membership of the JIT where it can influence the investigation and exert veto power over the dissemination of findings.

Perhaps reporters should now be asking the Ukrainian military to go away and find this specific missile and hold their own press conference where they can expose the serial number of the one they have in their possession.

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Novichock detection and the Salisbury tourists

Image credit: EU Today.

The Salisbury novichok poisonings are a real can of worms. Media coverage is obviously politically, rather than scientifically, driven. Social and mass media reporting is highly partisan and the scientific components and reports (which are mostly classified) can become slaves to the particular political masters. I find the whole drama a mystery and certainly do not want to tie myself to any of the conspiracy theories, official or otherwise, that are floating around. It’s probably a subject to keep well away from.

However, one aspect intrigues me – the claimed identification of novichock residues in the London hotel room used by the Russian duo, Alexander Petrov and Ruslan Boshirov. In particular, is the identification of the material reliable and, further, is the reporting of this identification factual and reliable?

Media reporting: This generally assumes a positive identification, although at trace levels. The Sun, for example, reported:

“Petrov and Boshirov stayed in the City Stay Hotel in Bow, East London, during their time in the UK.

Cops searching their room two months later on May 4 are said to have discovered minute traces of Novichok, a high-grade military nerve agent created by Soviet scientists.”

And later:

“police found traces of Novichok in the hotel room in which the pair stayed for two nights.”

Similarly, the Independent reported:

“Investigators later found traces of novichok in their room at the City Stay Hotel.

They said the amount was too low to present a health risk but are appealing for any hotel guests who stayed there between 4 March and 4 May to contact investigators.”

Since Petrov and Boshirov surfaced and were interviewed the media coverage has become even more partisan and the discovery of these traces of novichock is being portrayed as even more definite.

The police reportIn the absence of an official scientific report of the analyses this is the best we have to go on:

“On 4 May 2018, tests were carried out in the hotel room where the suspects had stayed. A number of samples were tested at DSTL at Porton Down. Two swabs showed contamination of Novichok at levels below that which would cause concern for public health. A decision was made to take further samples from the room as a precautionary measure, including in the same areas originally tested, and all results came back negative. We believe the first process of taking swabs removed the contamination, so low were the traces of Novichok in the room.

Following these tests, experts deemed the room was safe and that it posed no risk to the public.”

This raises more questions, for the scientifically inclined, than the answers, seemingly, provided:

  • How many samples were taken – 2 positives is probably a low proportion of the total measurements?
  • Where were the sample sites located in the room
  • How do the low levels reported compare with the detection limits for the methods used?
  • Was the decision to take further samples based on lack of confidence in the results form the first sampling?
  • Again, how many further samples were taken and from what sites in the room?

I suspect that the two positive detections were probably false positives which the analyst had low confidence in. It is likely many samples were taken from the room so that two positives near, or at, the level of detection is not a good result. I suspect experts would challenge this evidence in court.

Absence of evidence is not proof of innocence

I should stress that in questioning the results I am not trying to argue for the innocence of the two guys. After all, a true professional would not have contaminated the hotel room. If the evidence is genuine, though, it may be more suggestive of a non-professional or non-state actor than a professional hitman.

The problem, though, at this stage is that all the other evidence made public is circumstantial and unlikely to stand up in court. The claimed positive detection of novichock-type compounds in the hotel room could be the key to a successful conviction so any doubts should be removed.

Novichock compounds

The following presents my views on the problems of detecting novichock compounds at low levels and why I think we should not accept the current media reports as positive evidence. A court would have to look very critically at the actual data and detection methods used. At the moment the political and police statements could be expressing far more confidence in the reported findings than is actually warranted by the real evidence.

An Iranian paper from two years ago, Hosseini et al., (2016) provides information on the synthesis, structure and detection of novichock-type compounds. It is probably the most up-to-date information publicly available and its citation is

Hosseini, S. E., Saeidian, H., Amozadeh, A., Naseri, M. T., & Babri, M. (2016). Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry. Rapid Communications in Mass Spectrometry, 30(24), 2585–2593.

The paper describes the micro-synthesis of two compounds that are listed under Schedule 2.B.04 of the Chemical Weapons Convention. These are:

  • Compound 3: N-[Bis(dimethylamino)methylidene]-P-methylphosphonamidic fluoride, and
  • Compound 4: O-alkyl N-[bis(dimethylamino)-
    methylidene]-P-methylphosphonamidate Novichok derivatives

The figure shows the chemical structures of these compounds.

The F atom in compound 3 is replaced by an organic group (R) to form the novichok derivative. As this can be either of a wide range of organic groups (the authors list nine different groups for derivatives they synthesised) the novichock-type compounds include a range of different chemicals with differing levels of toxicity.

This is why more official reports on the Salisbury poisonings refer to novichock-type nerve agents and not just novichock.

Before any clever reader decides to use this paper to synthesize their own samples of these or similar compounds I must stress the warning provided by the authors:

“It should be noted that, due to the extreme toxicity of these materials, the separation and purification of CWC-related chemical are very difficult and therefore should be carried out only by a trained professional in an efficient fume cupboard equipped with an active charcoal filtration system.”

Detection of novichok-type compounds

Mass spectrometry methods are used for detection. This involves breaking up the molecules into fragments using an electron ionizer (EI). These molecular fragments are then separated according to mass and charge and the amounts of each detected in a mass spectrometer (MS) to produce an EI-MS spectrum.

Each compound has its own “fingerprint” – a pattern of peaks defined by the mass/charge (m/z) of each molecular fragment and the relative intensity of each peak. The figure below shows the EI-MS “fingerprints” for compound 3 and the O-ethyl derivative of compound 4.

We can see why the detection of a compound relies not only on a single peak but also other characteristic peaks and their relative sizes.

For example, the largest peak (H) at m/z = 71 occurs in both compounds. This is because the molecular fragment (see the chemical structure to the right) responsible for it is produced by ionization of both compounds. So that peak cannot be used alone to differentiate between the two compounds. Identification of a specific compound requires locating all the major characteristic peaks and ensuring their relative intensities are correct.

This is straightforward where the compounds are available at relatively high concentrations and the combination of mass spectroscopy with gas or liquid chromatography helps to remove some of the background chemicals. The ability of UK experts to conclude that the type of novichok used to poison the Skripals is the same as that in the fake scent bottle used by the second victims (Dawn Sturgess and Charlie Rowley) means that they were able to recover samples containing the nerve agent at sufficiently high concentrations.

But, at low concentrations one may simply not be able to find all the characteristic peaks, and identification using just the most intense peaks is not so reliable. For example, compounds 3 and 4 could not have been differentiated at low concentrations if all that could be detected were very small peaks at m/z =  71, 135 and 150. Yet that is the situation when searching for trace levels and one is always conscious that the peaks that are detected could be due to low levels of a completely different compound.

Conclusions

I suspect the description of the two possibly positive samples in the London Hotel as trace levels or “at levels below that which would cause concern for public health” were interpretations driven by “wishful thinking” and exaggerated confidence and not surety. After all, scientists often face such pressures when their political masters are looking for results to fit a preconceived narrative. It is easy to be persuaded in such situations. And it is tempting for both scientists and police to describe their findings in a more confident way when presenting to the media than they would during peer discussions in the laboratory or office.

My suspicions are supported by the fact that the total number samples taken from this hotel room must have been quite large so that makes the reliability of the positive values at such low levels for only two samples quite suspect (although information on locations of sampling sites would help this interpretation).

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