Chlordecone

Last updated on 03/15/2011

Chlordecone is an organochloride insecticide which was extensively used against the banana weevil in the French West Indies between 1973 and 1993. It is a stable compound in the environment which is responsible for significant soil and water pollution and can contaminate some animal and vegetable produce.  The inhabitants of these regions are therefore constantly exposed to chlordecone. Studies conducted in 1989 demonstrated the carcinogenic properties of this substance in rats and mice. Chlordecone is an endocrine disruptor, classified by the IARC as potentially carcinogenic in humans (group 2B).

These factors were taken into account in the National Environmental Health Plan (PNSE1- action 12 and PNSE2 - action 35), and led to the implementation of the Chlordecone Action Plan in Martinique and Guadeloupe 2008-2010, which was mainly designed to:

• improve health monitoring of the population and knowledge of the clinical and environmental problems associated with chlordecone;

• continue to reduce the exposure of the population to chlordecone;

• offer agricultural assistance and improve monitoring of soil and family garden produce.

This plan, which involved around 40 initiatives, received funding amounting to over € 33 million. Its main findings related to:

Reduction of Exposure

• The limit values of chlordecone in foodstuffs were reduced to 10 and 20μg/kg of fresh weight in July 2008;

• as a preventive measure, vegetables sensitive to chlordecone contamination are now only grown on healthy soil or soil with a contamination level compatible with their growth;

• fishing and eating  fish and shellfish are banned in  contaminated areas;

• finally, tests  have demonstrated the high quality of the public water supply and the foodstuffs marketed, and can identifyproducts liable to carry risks of contamination exceeding the Maximum Residue Limits (MRL).

Increasing Knowledge about Transfers and Contamination of the Environment

• guidelines on  the crops which may be grown depending on the level of soil contamination have been produced and provided to producers;

• water contamination is beginning to be better demarcated, and this data has been used to introduce measures designed to prevent high levels of exposure;

• a geographical information system has been implemented to collect the results of georeferenced soil analysis.

The Laboratories

Three French West Indian laboratories have been better equipped to test for chlordecone in water, soil and plants.

The Search for Remedies to Soil Pollution

An international seminar, held in May 2010, drew up a set of guidelines for short-, medium- and long-term research aimed at finding solutions to remedy soil pollution and set up catchment areas to test decontamination processes.

Health – Improvement of the Monitoring System, Scientific Committee and Conduct of Studies

A cancer register has been set up in Guadeloupe, and the Martinique cancer register has been reinforced. An interregional register of congenital malformations has been created. A toxicovigilance centre is being set up.
A Scientific Council, set up as part of this plan, published the report “ Health impact of the use of chlordecone in the French West Indies“ in October 2009. It comprises a set of recommendations for epidemiological research, monitoring of the population’s health, and implementation of the policy of preventing high levels of exposure.

The 2011-2013 Action Plan

The 2011-2013 action plan against chlordecone pollution in Guadeloupe and Martinique was launched in March 2011 to pursue the activities initiated in the first plan. It follows on from the previous Plan, and revolves around four objectives:

1. analysing the state of knowledge of the environment, and researching and experimenting with techniques for remedying pollution;
2. consolidating the system of monitoring the population’s health, and analysing the effects on their health 
3. continuing to reduce the exposure of the population, while ensuring the quality of local food production and supporting the professionals affected; 
4. managing the contaminated areas and providing good information to the population.

This second plan includes a component involving fishing and waters, to deal with the contamination highlighted by the first plan, especially marine pollution. It implements 36 initiatives to a value of € 31 million, already earmarked by the government.

Studies on Chlordecone

Moreover, in March 2010 InVS published a report on “The health impact of the use of chlordecone in the French West Indies – Recommendations for research and public health actions”, and in June 2010, researchers from Inserm published the results of a case-control study* which showed a possible association between exposure to chlordecone and prostate cancer (Multigner L, 2010). The results are based on the Karuprostate research programme. The authors found that the risk of prostate cancer increased with the plasma concentration of chlordecone: OR 1.77; 95% CI [1.21-2.58] (multivariate analysis) for concentrations exceeding 0.96 µg/L. Increased risk is also seen with cumulative exposure in the highest quartile: OR 1.73; 95% CI [1.04-2.88] (multivariate analysis). An increased risk of prostate cancer was also found in people with a family history of prostate cancer and those who had lived in Western countries. The results led the authors to suggest that the association between exposure to chlordecone and the risk of prostate cancer may be affected by genetic mutations combined with environmental factors relating to diet and lifestyle, especially an interaction with residence in a Western country. This interaction may be explained by environmental exposure acquired during residence abroad, especially co-exposure to other chemical agents or change of diet. The authors considered that additional investigations were necessary.

* Chlordecone Exposure and Risk of Prostate Cancer, Luc Multigner et coll., J Clin Oncol 28.