| Summary: | 碩士 === 南華大學 === 環境管理研究所 === 91 === The coastal regions of southwestern Taiwan are subjected to arsenic (As) pollution from groundwater. To use the groundwater for aquaculture may cause an overexposure of arsenic.The bioaccumulation, as well as acute and chronic toxicities of As, in aquacultural milkfish (Chanos chanos) from blackfoot disease (BFD) area were studied. Water and milkfish samples were collected from the milkfish farms in the BFD areas of Putai, Yichu, Pemen and
Hsuechchia, respectively. The samples were analyzed to estimate the concentration of As in the aquacultural systems and to assess the bioaccumulation of As in fish. Arsenic concentrations of the pond water in Putai, Yichu and Hsuechchia are high than the standard of aquacutural water 50 mg L-1. The resulting values of bioconcentration factor (BCF) of As in fish is correlating with the body weight of the fish (W) as BCF=14.15e-0.002W , where the median lethal concentration (LC50 value) for milkfish shows a significant allometric,negatively correlation with the exposure time as LC50 (t)=134.69t-0.7175, where LC50 (t) is the median lethal concentration (mg ml-1) and t is the exposure time (h). Lethal internal residue of As in fish body that causes 50% mortality (C(L,50) value) is negatively correlating with the median lethal time (LT50 value) as C(L,50)=247.47LT50 -0.7175, where C(L,50) is the lethal internal residue of As in fish body that causes 50% mortality (mg ml-1) and LT50 is the median lethal time (h). The C(L,50) value is a liner function of As concentration in water as C(L,50) =63.97+0.92Cw, where Cw is As concentration in water (mg L-1). It showed that the C(L,50) value increased with Cw; whereas the time to death of the fish was decided by the As
concentrations in the target tissues of fish. The results of chronic toxicity experiment showed a high accumulation of As in milkfish (847.00 ± 640.08 mg g-1) from the 2nd to 8th day, and then decreased, which indicated that the depuration in milkfish is equal to uptake.
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