Category Archives: Human Health Impacts

Eating predatory fish linked to methylmercury in humans

I belong to an international network called International POPs Elimination Network which has obtained small grants to fund research for its global CSO members.  Their ambit widened to toxics which fall under the categories for all the UN conventions on Chemicals & Wastes, because of the recognized interlinkages among issues.

 While for Pacific Islands the emphasis is on improving management of chemicals and wastes rather than technical expertise with regard to industrial byproduts, there are still not many Pacific CSOs who follow these multilateral environmental agreements.

I was happy with the  emphasis during the Health Conference on research to gather data to support policy-making

First, there is the same issue mentioned by Dr Maoate in his keynote speech i.e. translating European terms into Cook Islands maori.  I tend to characterize bad chemicals as vairaku kino, that is “bad medicine”. We have  had advisory  fact sheets about mercury   translated into maori by former Parliamentary translator.  We decided to coin the phrase “mecurio” for mercury because the periodic table of elements has not been translated.

The second point I would like to reinforce  is the targeting specific populations with regard to interventions.

My third point is focus on minimizing risks to human health and environment from methlymercury

UN Environmental Program has an initiative called Strategic Approach to International chemicals Management (SAICM) which provides a forum for industry, academia, practitioners, government policymakers and negotiations; and civil society organisations or NGOs.   Under SAICM, one of the current emphases is to engage the health sector in effective, safe management of chemicals and waste, starting at international level with WHO and working successively down through regional, subregional and national levels. 

Brain damage resulting from methylmercury exposure in utero has similar social consequences to those characterized earlier in the Conference with regard to exposure to alcohol.  So the key message is about reducing exposure to toxics that will have lifelong impacts on a person’s life.

The  United States Geological Service or USGS carried out a ground-breaking study in 2009.  The aim was to find the origins of methylmercury in the North Pacific Ocean, and how it gets into fish.

It was estimated that 75% of human exposure to mercury globally was from fish or shellfish, but nobody knew how it got there.  It was further estimated that about 40% of U.S. exposure was from Pacific fish, but there were no research results available.

In 2009, the USGS published its findings in a report entitled “Mercury Sources, Distribution & Bioavailability in the North Pacific Ocean: Insights from Data & Models”.  The complex methylation process was explained

US Environmental Protection Authority (US EPA) commented that one unexpected finding was the significance of long-range transport by large ocean circulation currents from the west to the east.  Typically it was though that emissions were due to land-based combustion activity but this particular study concluded that emissions originated near Asia.

 

Some sceptics dispute this; and others have commented that radionucleoide technology can be used to determine from which continent the combustion source originated. 

 An important point for the Cook Islands is that “global deposition” explains why islands so far from the continents should be affected when there are no  nearby sources such industrial processes or coal-based power stations.

 In Europe, PRTRs (“pollutant release and transfer registers”) were set up to monitor pollutant releases under a regional convention called the Aarhus Convention.   Air quality monitoring is also carried outin the Arctic.  Perhaps the Pacific region could do with a similar monitoring system.

WHO Report – Glyphosate probably causes cancer

IARC MONOGRAPHS VOLUME 112: EVALUATION OF FIVE ORGANOPHOSPHATE INSECTICIDES AND HERBICIDES  

NOTE: Glyphosate is sold in the Pacific as “Round Up”

WHO International Agency for Research on Cancer

http://www.iarc.fr/en/media-centre/iarcnews/pdf/MonographVolume112.pdf 

Lyon, France, 20 March 2015 – The International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization, has assessed the carcinogenicity of five organophosphate pesticides. A summary of the final evaluations together with a short rationale have now been published online in The Lancet Oncology, and the detailed assessments will be published as Volume 112 of the IARC Monographs.  

What were the results of the IARC evaluations?  

The herbicide glyphosate and the insecticides malathion and diazinon were classified as probably carcinogenic to humans (Group 2A).    

The insecticides tetrachlorvinphos and parathion were classified as possibly carcinogenic to humans (Group 2B).    

What was the scientific basis of the IARC evaluations?  

The pesticides tetrachlorvinphos and parathion were classified as possibly carcinogenic to humans (Group 2B) based on convincing evidence that these agents cause cancer in laboratory animals.  

For the insecticide malathion, there is limited evidence of carcinogenicity in humans for non-Hodgkin lymphoma and prostate cancer. The evidence in humans is from studies of exposures, mostly agricultural, in the USA, Canada, and Sweden published since 2001. Malathion also caused tumours in rodent studies. Malathion caused DNA and chromosomal damage and also disrupted hormone pathways.  

For the insecticide diazinon, there was limited evidence of carcinogenicity in humans for non-Hodgkin lymphoma and lung cancer. The evidence in humans is from studies of agricultural exposures in the USA and Canada published since 2001. The classification of diazinon in Group 2A was also based on strong evidence that diazinon induced DNA or chromosomal damage.  

For the herbicide glyphosate, there was limited evidence of carcinogenicity in humans for non-Hodgkin lymphoma. The evidence in humans is from studies of exposures, mostly agricultural, in the USA, Canada, and Sweden published since 2001. In addition, there is convincing evidence that glyphosate also can cause cancer in laboratory animals. On the basis of tumours in mice, the United States Environmental Protection Agency (US EPA) originally classified glyphosate as possibly carcinogenic to humans (Group C) in 1985. After a re-evaluation of that mouse study, the US EPA changed its classification to evidence of non-carcinogenicity in humans (Group E) in 1991. The US EPA Scientific Advisory Panel noted that the re-evaluated glyphosate results were still significant using two statistical tests recommended in the IARC Preamble. The IARC Working Group that conducted the evaluation considered the significant findings from the US EPA report and several more recent positive results in concluding that there is sufficient evidence of carcinogenicity in experimental animals. Glyphosate also caused DNA and chromosomal damage in human cells, although it gave negative results in tests using bacteria. One study in community residents reported increases in blood markers of chromosomal damage (micronuclei) after glyphosate formulations were sprayed nearby.  

How are people exposed to these pesticides?  

Tetrachlorvinphos is banned in the European Union. In the USA, it continues to be used on livestock and companion animals, including in pet flea collars. No information was available on use in other countries.  

Parathion use has been severely restricted since the 1980s. All authorized uses were cancelled in the European Union and the USA by 2003. 

Malathion is currently used in agriculture, public health, and residential insect control. It continues to be produced in substantial volumes throughout the world. Workers may be exposed during the use and production of malathion. Exposure to the general population is low and occurs primarily through residence near sprayed areas, home use, and diet.  

Diazinon has been applied in agriculture and for control of home and garden insects. Production volumes have been relatively low and decreased further after 2006 due to restrictions in the USA and the European Union. Only limited information was available on the use of these pesticides in other countries.  

Glyphosate currently has the highest global production volume of all herbicides. The largest use worldwide is in agriculture. The agricultural use of glyphosate has increased sharply since the development of crops that have been genetically modified to make them resistant to glyphosate. Glyphosate is also used in forestry, urban, and home applications. Glyphosate has been detected in the air during spraying, in water, and in food. The general population is exposed primarily through residence near sprayed areas, home use, and diet, and the level that has been observed is generally low.  

What do Groups 2A and 2B mean?  

Group 2A means that the agent is probably carcinogenic to humans. This category is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. Limited evidence means that a positive association has been observed between exposure to the agent and cancer but that other explanations for the observations (called chance, bias, or confounding) could not be ruled out. This category is also used when there is limited evidence of carcinogenicity in humans and strong data on how the agent causes cancer.  

Group 2B means that the agent is possibly carcinogenic to humans. A categorization in Group 2B often means that there is convincing evidence that the agent causes cancer in experimental animals but little or no information about whether it causes cancer in humans.   Why did IARC evaluate these pesticides? The IARC Monographs Programme has evaluated numerous pesticides, some as recently as 2012 (anthraquinone, arsenic and arsenic compounds). However, substantial new data are available on many pesticides that have widespread exposures. In 2014, an international Advisory Group of senior scientists and government officials recommended dozens of pesticides for evaluation. Consistent with the advice of the Advisory Group, the recent IARC meeting provided new or updated evaluations on five organophosphate pesticides.   

How were the evaluations conducted?  

The established procedure for Monographs evaluations is described in the Programme’s Preamble. Evaluations are performed by panels of international experts, selected on the basis of their expertise and the absence of real or apparent conflicts of interest. For Volume 112, a Working Group of 17 experts from 11 countries met at IARC on 3–10 March 2015 to assess the carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. The in-person meeting followed nearly a year of review and preparation by the IARC secretariat and the Working Group, including a comprehensive review of the latest available scientific evidence. According to published procedures, the Working Group considered “reports that have been published or accepted for publication in the openly available scientific literature” as well as “data from governmental reports that are publicly available”. The Working Group did not consider summary tables in online supplements to published articles, which did not provide enough detail for independent assessment.  

What are the implications of the IARC evaluations?  

The Monographs Programme provides scientific evaluations based on a comprehensive review of the scientific literature, but it remains the responsibility of individual governments and other international organizations to recommend regulations, legislation, or public health intervention.  

Media inquiries: please write to com@iarc.fr. Thank you.