Bioaccumulation of heavy metals in aquatic biota from Khon Kaen city wastewater treatment system
1999
Warangkana Sungsitthisawad | Thawatchai Nienvitoon | Uriwan Inmuang | Thirapong Thiramanus
Khon Kaen City wastewater treatment system receives almost all domestic and industrial sewage approximately daily loading 25,500 cubic m/day, serving 142,926 population or at least 35,585 houses and including 568 industries. A lot of people come to catch fishes and take vegetables from wastewater treatment system. So this research aims to determine heavy metals concentration because substance in wastewater can accumulate heavy metals into its components, which in long term intake those aquatic biota may give rise to health problems. Cd, Cu, Pb and Zn were examined in wastewater 30 samples, sediment sludge 15 samples, Tilapia 20 samples, morning glory 20 samples from January to May 1998. The result showed characteristics of wastewater pH range from 7.2-8.8, DO 3.5-6.2 mg/L, BOD5 16.5-51.2 mg/L, COD 66-87 mg/L, the concentration of heavy metals in wastewater were high (PbCuZnCd). Pb, Cu, and Cd concentration were decreased after wastewater was treated, however the concentration of Zn was rather constant. The sediment accumulated heavy metals varied from the highest to lowest; for Zn (4.893-284.3 mg/kg), Cu (0.06-16.385 mg/kg), Pb (0-9.15 mg/kg), and Cd (0-1.325 mg/kg). The Tilapia generally was found to have higher content of heavy metals, Tilapia's organs having heavy metals in skin grillbonemixfillet. Concentration of Zn in fish-organs was the highest, while the Cu and Pb were relatively lower. Heavy metal concentrations in morning glory indicated heavy metals of the tip and leaf were higher than the whole (Zn 7.62-26.394 mg/kg, Cd 2.54-10.944 mg/kg, Cu 0.46-1.253 mg/kg and Pb 0.01-0.746 mg/kg), almost morning glory concentration exceed the standard. Hence, fishes and vegetables can give rise to the health problems to consumers. It is necessary to be awareness.
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