Heavy Metals in Seawater, Sediments, and Snail Biota Collected From Coastal Waters of Indragiri Hilir Regency, Riau Province, Indonesia
Sea snails with the type of Ceritihidea obtusa are commonly found in muddy coastal areas in the mangrove ecosystem and as a popular seafood in Riau Province, but these coastal areas also receive household waste, agricultural activities, industrial and marine sailing traffic. Information on coastal pollution in this region is minimal, especially heavy metals in water, sediment and bioconcentration factors in this snail. In this study, 3 locations in Tanjung Pasir Village were selected as the main collection and source of the largest C. obtusa supply for consumption inside or outside the region. Aspects evaluated were concentrations of heavy metals (Pb and Zn) in seawater, sediment and snail meat. The results found that there was heavy metal in the water with levels above the limit of sea water, including snail meat especially Pb above the national and international legal limits for human consumption, except in sediments. A positive relationship was found between concentrations of Pb and Zn in water or sediments with higher snail meat compared to the relationship between concentrations of both heavy metals in water and sediment. The bioconcentration factor for Pb was found to be higher than that of Zn especially accumulated from the water column with the accumulated level of the two metals being moderate. The results indicate that pollutants from local coastal community activities become the source of these heavy metals and pretreatment of these snails needs to be given in order to achieve legal limits for consumption.