Seasonal variation of heavy metals in water, sediment, and highly consumed cultured fish ( Labeo rohita and Labeo bata ) and potential health risk assessment in aquaculture pond of the coal city, Dhanbad (India)

Abstract

The extent of heavy metal pollution and their impact on the various component of urban aquaculture pond (India) were investigated on the basis of seasonal variation. The water, sediment, and fish samples (Labeo rohita and Labeo bata) were collected and analyzed to assess the metal toxicity. In the sediment, geoaccumulation index (I_geo), contamination factor (CF), pollution load index (PLI), and ecological risk index (ERI) were calculated. The estimated daily dietary intake (EDI) for As, Cd, Cr, Mn, Pb, and Zn was estimated in adult and children on the basis an average amount of fish consumed by the Indian people and its associated health hazard with was also assessed in terms of target hazard quotients (THQs). The concentration of metals in all the analyzed samples was found higher during pre-monsoon season. While, in case of fish, L. bata species has higher metal accumulation rate during both the seasons than the L. rohita because of their bottom dweller feeding habit. The order of metals in L. bata muscles is Zn > Mn > Pb > Cr > As > Cd. The I_geo value for Zn (2.66 to 3.68) was found to be highest and followed by Cd (1.65 to 3.52) and Pb (1.52 to 2.55) indicating moderate to highly polluted sediment quality. The values of ERI were significantly high during pre-monsoon period and varied from 319 to 557, representing very high metal contamination. From the human health perspective, present study highlighted that the local inhabitants who rely on this valuable pond for fish consumption are exposed chronically to As and Pb pollution due to higher THQ values, especially from the intake of L. bata.