EXAMINATION OF LEAD AND CADMIUM CONTAMINATION IN MARKET- SOURCED FILOPALUDINA BENGALENSIS FROM JHAPA, MORANG AND SUNSARI DISTRICTS, EASTERN NEPAL.

Abstract

Heavy metal pollution from contaminated water sources threatens aquatic life and human health. In eastern Nepal where Freshwater Snails (Filopaludina bengalensis) are commonly consumed as an edible mollusc, these pollutants may be absorbed into the snails through polluted waters which could cause harm to those who consume them and to assess the level of lead (Pb) and cadmium (Cd) present in snails sold at various markets in Jhapa, Morang and Sunsari districts in eastern Nepal, Atomic Absorption Spectrophotometry (AAS) was used to measure the levels of these metals and statistical analysis was carried out to compare the levels of each metal within each of the sampled locations and also to find the association between Pb and Cd. A comparison of the average amount of Pb and Cd measured indicated that Pb was significantly greater than Cd at all the sampling locations. At Site 3, the highest overall concentration of heavy metals was observed while Site 5 demonstrated the lowest concentrations of heavy metals of both Pb and Cd. One-way Anova and Kruskal Wallis Tests revealed significant variation in Pb and Cd levels among sample sites (p<0.05). Analysis of paired comparisons confirmed that Pb levels were always greater than Cd levels at each site. However although there was a moderate positive association between Pb and Cd levels over sites this association was not statistically significant. These observations provide evidence for regional variations in the degree of contamination by heavy metals in Filopaludina bengalensis obtained from markets in eastern Nepal, also with lead being more problematic than cadmium in terms of contamination. Therefore, the results represent important baseline data on the levels of heavy metal contamination in commercially harvested freshwater snails and highlight the need for continued monitoring of freshwater foods for public health protection and improved food safety management in Nepal