Risk characterization of perfluoroalkyl acids exposure of aquatic organisms in Lake Shiwha, Korea.

摘要

The Shihwa-Banweol Industrial Complexes (SBIC), located on the west coast of Korea, is one of the main national industrial complexes with a wide range of industries currently operating. Recently, significant quantities of perfluoroalkyl acids (PFAs) were observed in the waters of Lake Shihwa receiving wastewaters from SBIC. Thus, it was deemed timely to determine concentrations of PFAs in aquatic animals of Lake Shihwa and assess the potential risks that these compounds might pose to aquatic wildlife in Lake Shihwa.; Aquatic samples (fish, blue crab, mussel, and oyster) and bird eggs were collected in May to June 2006 from the Lake Shihwa area. All biotic samples contained measurable concentrations of significant level of PFAs in their tissues. PFOS was the predominant PFAs in fish species (mullet, rockfish, and shad), followed by the longer chain perfluorocarboxylic acids (PFCAs), PFUnA > PFDA > PFDoA > PFNA > PFOA. In the egg yolks of birds (little egret, little ringed plover, and parrot bill), measured concentrations of PFOS were similar to birds eggs from other urban areas, but greater than those from remote regions.; The spatial distribution of PFOS concentrations in marine organisms demonstrates that biota samples from sites close to the outlets of inland creeks were more contaminated than those sampled at sites away from the release sources. This observation is consistent to the distribution of water-borne PFOS in Lake Shihwa. It could be said that wastewaters from SBICs are at least one identified source of PFAs into Lake Shihwa, consequentially contributing the elevated PFAs concentrations in the marine wildlife.; In pharmacokinetic study, PFOS has a half-life of almost four months in male chickens; in contrast, greater than half of introduced PFOA was eliminated within a week. Thus, combined with a greater PFOS and a lesser PFOA in birds from the Lake Shihwa area, at least current PFOA concentrations are unlikely to cause acute effects to birds.; For the hazard assessment of fish, PFOS body residues were compared to a benchmark tissue concentration that would not be expected to cause acute effects in fish. The calculated hazard quotients (HQs) were less than 1.0 for all species. Even a HQ estimated from the greatest PFOS in fish was only to be 6x10-4. Thus, at least current concentrations of PFOS in fish living in Lake Shihwa are not likely to cause acute lethality.; Multiple lines of evidence were used to assess the PFAs associated-risks on birds, which are one of the top-predators in the food web of the Lake Shihwa region. From a bottom-up approach using fish as a sole diet for birds, a range of HQ (8.0x10-3--9.0x10-3) generated was hundred-folds less than the least observable adverse effect level (LOAEL) for PFOS. Similarly, the calculated HQs based on residue concentrations in egg yolk were 8.0x10-3 for PFOS only and 9.0x10 -3 for a mixture of PFAs, respectively, when the LOAEL used as a benchmark dose. Although there are many uncertainties in deriving these risk values, similar risk estimates from two opposite but complimentary approaches indicate that current concentrations of PFOS and a mixture of PFAs would not be expected to pose adverse effects to the avian population around the Lake Shihwa area.