In a paper of Dreiher et al. published in your journal in December 2005,1 the authors claim that pollution of groundwater (downstream) with toxic volatile compounds (pesticide residues) from an industrial site in southern Israel, is a plausible causative source for the excess in the incidence of NHL that they have observed in residents within 14 km of the industrial park. They state “we found a possible association between the incidence of NHL and groundwater contamination with volatile toxic chemicals”. However, they have failed to mention that all residents of this area, those within 14 km and those farther away, are sharing the same system of water supply (that of the national water system) that provides this region with water from northern parts of the country. The drinking water supplied by the national water carrier is examined on a periodic basis for micro-contaminants and is only approved for use by the Ministry of Health when all chemical and microbiological tests are within the national standards. Further more, the majority of the patients came from the city of Beer Sheva which is “upstream” from the industrial park.
Thus, contaminated drinking water by wastes (effluents) from the concerned industrial area could not provide an explanation for the higher than expected incidence rate that they have observed.
It is very unfortunate that when scientists conduct an “ecological” study, the fail to consider such basic ecological characteristics of the concerned geographic area and draw far reaching conclusions which are not based on plausible reasoning.
References
- Dreiher J. Non-Hodgkin’s lymphoma and residential proximity to toxic industrial waste in southern Israel. Haematologica. 2005; 90:1709-10. Google Scholar