水体中多溴联苯醚污染及其生态风险

水环境是多溴联苯醚（PBDEs）的主要环境归宿之一,研究水环境中PBDEs污染对于了解PBDEs的环境生物地球化学过程及其生态风险具有重要意义。基于水相、沉积相和水生生物中PBDEs污染的报道,从多介质分布特征、污染来源、变化趋势以及PBDEs的水生生物累积和生物放大等方面综述了水环境中PBDEs的污染及其生态风险,并讨论了我国水环境中PBDEs污染及其研究进展,指出了研究存在的问题和进一步研究的重点。     

Measurement of environmental trace-metal levels with transplanted mussels and diffusive gradients in thin films (DGT): a comparison of techniques

Transplanted mussels and diffusive gradients in thin films (DGT) were used to assess levels of cadmium, copper, lead and zinc at four sites situated inside and outside of two enclosed marinas, near Melbourne, Australia. Mussels accumulated all metals except cadmium. Over one year, there were large temporal differences in tissue metal levels in mussels, but differences between sites were only apparent for copper and lead. DGT showed temporal differences of the same kind as those seen in the mussels, but appeared to have more power to discriminate between sites. DGT found higher copper levels inside marinas than outside, and high levels of zinc were found inside one marina. Levels of copper and zinc were high enough to be of environmental concern for one site. The effect of fouling on DGT measurements will have to be quantified, or avoided by the use of multiple short-term exposures, if the technique is to become a widespread in situ monitoring tool.     

THE IMPACT OF METAL AND ORGANIC CONTAMINANTS ON THE STRUCTURE OF PERIPHYTON IN LOTIC SEDIMENTS: OBSERVATIONS AT VARIOUS SCALES

1 INTRODUCTION While wastewater discharge regulations have significantly reduced water column pollution, historical and accidental releases of organic pollutants and heavy metals continue to pose an ecological threat as these contaminants have become 搃n-place?sediment pollutants. It had been previously assumed that natural attenuation processes, such as burial or biodegradation, would decrease the contamination levels in surface sediments and, thus, diminish the environmental impact of t…     

Total mercury concentrations in lionfish (Pterois volitans/miles) from the Florida Keys National Marine Sanctuary,USA

Strategies to control invasive lionfish in the western Atlantic and Caribbean are likely to include harvest and consumption. Until this report, total mercury concentrations had been documented only for lionfish from Jamaica, and changes in concentrations with increasing fish size had not been evaluated. In the Florida Keys, total mercury concentrations in dorsal muscle tissue from 107 lionfish ranged from 0.03 to 0.48 ppm, with all concentrations being less than the regulatory threshold for limited consumption. Mercury concentrations did not vary consistently with standard lengths or wet weights of lionfish. In 2010, lionfish from the upper Keys had mean concentrations that were 0.03–0.04 ppm higher than lionfish from the middle Keys, but mean concentrations did not differ consistently among years and locations. Overall, total mercury concentrations in lionfish were lower than those in several predatory fishes that support commercial and recreational fisheries in Florida.     

The discrepancy in concentration of metals (Cu,Pb and Zn) in oyster tissue (Saccostrea glomerata) and ambient bottom sediment (Sydney estuary,Australia)

The current study aimed to examine the relationship between metals in sediments and metal bioaccumulation in oyster tissue in a highly-modified estuary (Sydney estuary, Australia). While extensive metal contamination was observed in surficial sediments, suspended particulate matter and oyster tissue, a significant relationship between these media could not be established. No relationship was determined between sediment quality guidelines and oyster size or weight, nor with human consumption levels for metals in oyster tissue. Moreover, oyster tissue metal concentrations varied greatly at a single locality over temporal scales of years. Oyster tissue at all 19 study sites exceeded consumptions levels for Cu. Bioaccumulation of metals in oyster tissue is a useful dynamic indicator of anthropogenic influence within estuaries, however oysters cannot be used in Sydney estuary as a valid biomonitor due to overriding internal regulation (homoestasis) by the animal, or by external natural (sediment resuspension) and anthropogenic (sewer/stormwater discharges) pressures, or both.     

Hypoxia does not promote naphthalene bioaccumulation in the brown shrimp, Penaeus aztecus

Since increased ventilation is known to be a common strategy used by aquatic animals to cope with hypoxia, we tested in present study the hypothesis that hypoxia can promote the bioaccumulation of naphthalene, a representative polycyclic aromatic hydrocarbon (PAH), in Penaeus aztecus, a penaeid shrimp subject to hypoxia and PAH contamination in the northern Gulf of Mexico. For each of the two naphthalene concentrations, five groups of shrimps were, respectively, subjected to five different conditions, namely, clean seawater under normoxia, seawater containing acetone under normoxia and hypoxia, and seawater containing 10 or 250 μg/L naphthalene under normoxia and hypoxia. Our results suggest that hypoxia does not significantly alter naphthalene bioaccumulation in either the gills or the hepatopancreas of P. aztecus. The absence of a promoting effect of hypoxia on naphthalene bioaccumulation is attributed to the increased disposition of naphthalene when the shrimps are subjected to hypoxia.     

Mercury in wahoo, Acanthocybium solandri, from offshore waters of the southeastern United States and the Bahamas

Wahoo, Acanthocybium solandri, are predatory oceanic fish that occur and are harvested in all tropical and subtropical oceans. Total mercury concentrations analyzed in dorsal muscle tissue of 208 wahoo from offshore waters of the southeastern United States and the Bahamas ranged from 0.021 to 3.4 mg/kg (wet weight), with a mean of 0.50 mg/kg (± 0.595 SD). Analyses indicated significant positive linear relationships between mercury and length, as well as, age of wahoo. The piscivorous nature, generally high trophic position, fast growth rate, and associated high metabolism of wahoo within tropical offshore pelagic environments may lead to comparatively higher concentrations of mercury over relatively short time periods. Mercury in wahoo, a highly mobile species consisting of one world-wide population, is regionally influenced by large-scale spatial differences in available mercury in selected prey fish species - many of which have been found to contain relatively high concentrations of mercury.     

Bioremoval of Cadmium by Lemna minor in Different Aquatic Conditions

This study was undertaken to determine the cadmium removal efficiency of Lemna minor when it was used for treatment of wastewater having different characteristics, i. e., pH, temperature and cadmium concentration. Plants were cultivated in different pH solutions (4.5–8.0) and temperatures (15–35°C) in the presence of cadmium (0.1–10.0 mg/L) for 168 h. The amount of biomass obtained in the study period, the concentrations of cadmium in the tissues and in the media and net uptake of cadmium by Lemna have been determined for each condition. The percentages of cadmium uptake (PMU) and bioconcentration factors (BCF) were also calculated. The highest accumulation was obtained for the highest cadmium concentration of 10.0 mg Cd/L as 11.668 mg Cd/g at pH 6.0, and as 38.650 mg Cd/g at 35°C and pH 5.0. The cadmium accumulation gradually increased with initial concentration of the medium, but the opposite trend was observed for the PMU. However, the maximum PMU was obtained as 52.2% in the solution with the lowest concentration of 0.1 mg Cd/L. A mathematical model was used to describe the cadmium uptake and the equation obtained was seen to fit the experimental data very well.     

Polycyclic aromatic hydrocarbon contamination and recovery characteristics in some organisms after the Nakhodka oil spill

Following the oil spill from the Russian tanker Nakhodka in 1997 in the Sea of Japan, polycyclic aromatic hydrocarbons (PAH) were monitored for three years in some molluscs from the Mikuni-cho shore in Japan. Total PAH concentrations in marine organisms except for spiny top shell, ranged from 5.3 to 32.7 ng/g wet weight, but no trends were evident. Total PAH concentration in spiny top shell (Turbo cornutus) was 44 ng/g w.w. in the first month after the oil spill. However, it rapidly decreased to less than 5.4 ng/g w.w. from the second month. Spiny top shell, which was exposed to dietary Nakhodka heavy fuel oil, concentrated benzo(a)pyrene to 17.1 ng/g w.w. after two weeks of exposure and then rapidly eliminated it during an elimination phase. These results suggest that spiny top shell accumulates PAHs because of their low ability to metabolize PAH, but it can excrete parent PAHs rapidly when removed from the source of contamination. Thus it is suitable as an indicator organism in monitoring oil contamination. It can also be inferred from these field and laboratory investigations that, in three years, organisms from the Mikuni-cho shore seem to have adequately recovered from the Nakhodka oil spill contamination.