The status of lead and cadmium in soils of high prevalenct gastrointestinal cancer region of Isfahan

BACKGROUND Cadmium and lead compounds are classified as human carcinogens by several regulatory agencies. Twenty five percent of all cancer-related deaths are attributed to gastrointestinal cancers (GI Ca). We investigated the levels of 2 different heavy metals (Cd and Pb) in the soils of the Lenjanat region, Isfahan province, Central Iran where intensive agriculture is surrounded by different industries like steel and cement-making factories and mining and gastrointestinal cancers are very common in this province. MATERIALS AND METHODS Two hundred topsoil samples (0-20 cm depth) were collected from agricultural and non-agricultural soils of the region and were analyzed for heavy metals. The metal contents were determined by flame atomic absorption spectrometry. RESULTS The findings of this study showed that frequency of gastrointestinal cancers in the study area have been increased in the recent years. Results of soil samples in this region showed that the mean concentration of Pb and Cd were more than 16 and 1 mg kg(-1), respectively. The total Cd concentration in most of the samples exceeded the suggested Swiss thresholds (0.8 mg kg(-1)) but the mean value of Pb concentration in soil was less than the threshold of 50 mg kg(-1) set by Swiss Federal Office of Environmental, Forest and Landscape. Compared to the threshold values for heavy metals (Cd and Pb) in soils, data showed that the studied fields were contaminated especially by Cd. CONCLUSION High heavy metals content in the soils seems to play an important etiological role in the carcinogenesis. Excessive accumulation of heavy metals in agricultural soils may not only result in soil contamination, but also lead to elevated heavy metal uptake by crops, and thus affect food quality and safety. Thus, analyzing heavy metals content in crops, water and dust could provide us a better insight to solve the problem.