Multiple exposure

Multiple exposure

That's the surmise of the Punjab Pollution Control Board's (ppcb) final report of a year-long study to explore high cancer rates in certain areas of Bhatinda district, Punjab.

ppcb had commissioned the School of Public Health (sph), department of public health, Post Graduate Institute of Medical Education and Research (pgimer), Chandigarh to conduct the study. The institute's report, 'An epidemiological study of cancer cases reported from villages of Talwandi Sabo block, district Bhatinda, Punjab', compares cancer incidence in Talwandi Sabo (referred to in the report as the study area) with that in Chamkaur Sahib block (described by the report as the control area) of Roop Nagar district, Punjab. Farmers in Talwandi Sabo use canal water and cultivate cotton while their counterparts in Chamkaur Sahib use ground water and cultivate rice or wheat. The rationale for selecting areas with different irrigation patterns was to ascertain links between canal irrigation and cancer. The study also tried to find if cotton cultivation -- much more pesticide-dependant compared to rice and wheat -- could be linked to cancer.

183,243 people making up 39,732 families were surveyed in 129 villages of both the blocks. "The number of confirmed cancer cases were 103.2 per lakh at Talwandi Sabo, compared to 71 per lakh at Chamkaur Sahib", notes the study. Prevalence of histologically (based on tissue tests) confirmed cancer cases at Talwandi Sabo was 125.4 per lakh while it was 72.5 per lakh at Chamkaur Sahib. "The age adjusted cancer death rate of Talwandi Sabo is higher than that of Barshi in Maharashtra -- the only rural centre in India that maintains cancer data. However, cancer mortality at Chamkaur Sahib was lower than Barshi," says Rajesh Kumar, head, department of community medicine, pgimer . Significantly, 63.8 per cent of cropped area in Talwandi Sabo was under cotton while the crop was not cultivated at all in Chamkaur Sahib. More than half of all the pesticides manufactured in the country are used in cotton. The sph study shows that many more people sprayed pesticides at Talwandi Sabo as compared to Chamkaur Sahib.

Ubiquitous toxins
sph tested water (tap and ground) and vegetables from the study and control areas. For the month of March 2004 heptachlor levels in tap water of Talwandi Sabo were 0.00004 parts per million (ppm) -- higher then the permissible limit (0.00003 ppm); this pesticide was not found in Chamkaur Sahib tap water. The April samples for groundwater showed similar results: hepatchlor levels of Talwandi Sabo was (0.006 ppm); they were again not present in Chamkaur Sahib water. Malathion in Talwandi Sabo's tap water samples of April 2004 was 0.21 ppm: 420 times higher than the permissible limit (0.0005 ppm). The pesticide was within permissible limit in Chamkaur Sahib water (0.00009 ppm). "The levels of heptachlor, a known carcinogen that's banned in India, were higher in samples of tap water in Talwandi Sabo compared to Chamkaur Sahib," concludes the report. "The same holds for groundwater too," it states.

The results of tests on vegetable samples were akin to the water studies (see table: The toxins in food). Chlorpyrifos and ethion levels were above permissible limits in vegetable samples of Talwandi Sabo.

The report observes: "It's difficult to pinpoint a single cause for cancer...A multi-pronged strategy to provide safe water supply, discouraging indiscriminate pesticide use.. is recommended." The technical committee to look into the report has recommended "a comprehensive study of the status of environmental health in other cotton growing areas of Punjab".