Dr. K. Divakaran Prathapan**
* Associate Professor, College of Agriculture, Padannakkadu
* Associate Professor, College of Agriculture, Vellayani.
Fifth meeting of the Conference of Parties to the Stockholm Convention held at Geneva in April 2011 has decided to add endosulfan to the United Nations’ list of persistent organic pollutants to be eliminated worldwide1. Endosulfan, a widely used insecticide, is targeted for elimination from the global market by 2012. Health problems in Kasaragod District in Kerala, where endosulfan was aerially sprayed for two decades, was the focal point of an international campaign that culminated in the global ban of the insecticide2. Circumstances link the alleged health problems in Kasaragod District in Kerala to the aerial application of endosulfan. The Achuthan Commission and the National Institute of Occupational Health (NIOH)3 that studied the issue, in 2001 and 2002 respectively, recommended a detailed epidemiological survey in the area. The epidemiological survey that was recommended by the expert committees was conducted only in 2010. This study was undertaken by the Calicut Medical College (CMC) under the Chief Investigatorship of Drs T. Jayakrishnan, C. Prabhakumari and Thomas Bina. The report of the study was published by the Centre for Science and Environment on their website and this critique is based on that publication4
Methodological issues
The CMC (Calicut Medical College) study is a comparison of the health problems of 1000 families of Bovikkanam in Muliyar Panchayath affected by the pesticide application with that of 850 families in Banam in Kodom-Belur Panchayath where no pesticide was applied. However, the people of Bovikkanam and Banam are not comparable as they are dissimilar socially and economically. The Muslim population in North Malabar are socio-economically backward5. The population of muslims in Banam is only 15% where as that of Bovikanam is 45%. This difference reflects in the food habits as well as the health and educational status of the people in these areas. A well designed study based on adequate number of representative samples would have yielded unequivocal and conclusive results.
Kasaragod is internationally known through the heart rending images of mentally challenged children carried by the print and visual media. Yet the published report of the study does not include such individuals, whose number can be exactly recorded. Endosulfan residues in the blood plasma of 41 subjects from 11 panchayaths were analyzed. However, no attempt was made to compare these values with those from the reference population, which is intriguing. Thus it is impossible to make comparisons and draw valid conclusions with regard to this important parameter under study. The various parameters of health studied were not properly defined. For example, there are many types of liver diseases including infective jaundice. It is not clear which types of liver diseases were included. Without providing working definition for a parameter, it cannot be studied clearly.
The conclusions of the CMC study are largely based on subjective parameters. The information gathered is mainly based on memory recall by the subjects. No effort was made to cross check this information with other easily available documented facts. For example, death and birth data is documented in the panchayath offices, which is a reliable source of information to study any possible change in the demographic pattern. Similarly, local veterinary hospitals record unnatural death in cattle. Banks and insurance companies too have a data base of morbidity and mortality in cattle as they pay compensation. No attempt was made to make use of such readily available information. The study was conducted at the peak of propaganda by the local Punchiri Club and the visual media. Hence it is highly probable that the responses of the subjects were biased and hence the inferences of the study are erroneous and misleading.
The reproductive health events in women above 30 years (whose reproductive period was during the period of aerial spraying) have been compared with those in women aged below 30 years (whose reproductive period started after the cessation of the aerial spraying). This study had been
designed to assess plausible improvement in the reproductive health of women following withdrawal of endosulfan application. The study report has specified that data on the reproductive heath events in all married women in the study area were collected. However, women are literally transplanted into the family of their husbands following marriage, under the Indian family system, for which Kasaragod is no exemption. This means, at least a section of the women studied by the CMC researchers were living outside the study area with their parents during the period of application of the insecticide. Similarly, many housewives in Banam (unsprayed reference area) are likely married into their respective families from the neighboring sprayed areas. This simple social reality is strong enough to contort the whole data and inferences on reproductive health events in women, as evidently the study is based on a mixture of subjects from both exposed and unexposed areas. Generally, a high proportion of young married men in muslim families in Muliyar work in gulf countries. As a result of the long spell of separation of couples, chances of conception are less and it is common that such couples seek infertility treatment. This is a strong factor that would distort the results of the study on the reproductive health of women as well as their infertility rates. Moreover, the data on reproductive health problems during the period of pesticide application (1980-2000) was never statistically compared with the same during the decade after cessation of the pesticide application.
Read more at https://sites.google.com/site/tokauorg/home/voice
Methodological issues
The CMC (Calicut Medical College) study is a comparison of the health problems of 1000 families of Bovikkanam in Muliyar Panchayath affected by the pesticide application with that of 850 families in Banam in Kodom-Belur Panchayath where no pesticide was applied. However, the people of Bovikkanam and Banam are not comparable as they are dissimilar socially and economically. The Muslim population in North Malabar are socio-economically backward5. The population of muslims in Banam is only 15% where as that of Bovikanam is 45%. This difference reflects in the food habits as well as the health and educational status of the people in these areas. A well designed study based on adequate number of representative samples would have yielded unequivocal and conclusive results.
Kasaragod is internationally known through the heart rending images of mentally challenged children carried by the print and visual media. Yet the published report of the study does not include such individuals, whose number can be exactly recorded. Endosulfan residues in the blood plasma of 41 subjects from 11 panchayaths were analyzed. However, no attempt was made to compare these values with those from the reference population, which is intriguing. Thus it is impossible to make comparisons and draw valid conclusions with regard to this important parameter under study. The various parameters of health studied were not properly defined. For example, there are many types of liver diseases including infective jaundice. It is not clear which types of liver diseases were included. Without providing working definition for a parameter, it cannot be studied clearly.
The conclusions of the CMC study are largely based on subjective parameters. The information gathered is mainly based on memory recall by the subjects. No effort was made to cross check this information with other easily available documented facts. For example, death and birth data is documented in the panchayath offices, which is a reliable source of information to study any possible change in the demographic pattern. Similarly, local veterinary hospitals record unnatural death in cattle. Banks and insurance companies too have a data base of morbidity and mortality in cattle as they pay compensation. No attempt was made to make use of such readily available information. The study was conducted at the peak of propaganda by the local Punchiri Club and the visual media. Hence it is highly probable that the responses of the subjects were biased and hence the inferences of the study are erroneous and misleading.
The reproductive health events in women above 30 years (whose reproductive period was during the period of aerial spraying) have been compared with those in women aged below 30 years (whose reproductive period started after the cessation of the aerial spraying). This study had been
designed to assess plausible improvement in the reproductive health of women following withdrawal of endosulfan application. The study report has specified that data on the reproductive heath events in all married women in the study area were collected. However, women are literally transplanted into the family of their husbands following marriage, under the Indian family system, for which Kasaragod is no exemption. This means, at least a section of the women studied by the CMC researchers were living outside the study area with their parents during the period of application of the insecticide. Similarly, many housewives in Banam (unsprayed reference area) are likely married into their respective families from the neighboring sprayed areas. This simple social reality is strong enough to contort the whole data and inferences on reproductive health events in women, as evidently the study is based on a mixture of subjects from both exposed and unexposed areas. Generally, a high proportion of young married men in muslim families in Muliyar work in gulf countries. As a result of the long spell of separation of couples, chances of conception are less and it is common that such couples seek infertility treatment. This is a strong factor that would distort the results of the study on the reproductive health of women as well as their infertility rates. Moreover, the data on reproductive health problems during the period of pesticide application (1980-2000) was never statistically compared with the same during the decade after cessation of the pesticide application.
Read more at https://sites.google.com/site/tokauorg/home/voice
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