[Effects of di-n-butyl phthalate on the antioxidant enzyme activities and lipid peroxidation level of Perna viridis].

A laboratory experiment was conducted to examine the superoxide dismutase (SOD) and catalase (CAT) activities and the lipid peroxidation (LPO) level presented by malondialdehyde (MDA) in visceral mass and mantle of green mussel (Perna viridis) after exposure to 0.5- 62.5 mg x L(-1) of di-n-butyl phthalate (DBP) for 15 days, and to study the change characteristics of these biochemical indicators after the green mussel released into DBP-free seawater for 10 days. During exposure period, the SOD activity in visceral mass was inhibited first and then reached the level of the control at 0.5 and 2.5 mg x L(-1) of DBP, but inhibited significantly (P< 0.01) at 12.5 and 62.5 mg L(-1) of DBP. The CAT activity in visceral mass was inhibited at all test concentrations of DBP, while the LPO level was obviously induced. During the chronic DBP exposure, the SOD and CAT activities in the mantle were induced significantly but had no regular pattern, and the LPO level was also obviously induced. After the exposed green mussel was released into clean seawater, the SOD and CAT activities in the visceral mass in 12.5 and 62.5 mg DBP x L(-1) groups recovered much slowly, but the LPO level gradually recovered to control level. During the recovery period, the SOD activity in the mantle showed an increasing trend with time, but the CAT activity and LPO level reached gradually to the level of the control.

Antioxidant responses and bioaccumulation in green-lipped mussels (Perna viridis) under acute tributyltin chloride exposure.

Green-lipped mussels (Perna viridis) were exposed to waterborne tributyltin chloride (TBTCl) at different concentrations (0.2, 0.4 and 0.8 µg L(-1)) for up to 72 h. Accumulated TBTCl in Perna viridis correlated linearly with the exposure concentrations of 0.2 µg L(-1)(R(2) = 0.772), 0.4 µg L(-1)(R(2) = 0.952), and 0.8 µg L(-1)(R(2) = 0.909). The results of superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA) all decreased in gill tissues after 24 h of exposure, but the hepatic SOD and the hepatic GPx showed either little or no effect on exposure of TBTCl solutions. Analysis using the Spearman rank correlation coefficient showed the hepatic GPx activity appeared to have a significant negative correlativity (R(s) = -0.42) with the exposed TBTCl concentrations, and the hepatic MDA was significantly negatively correlated (R(s) = -0.33) with the tissue TBTCl concentrations. Conversely, a significant positive correlation (R(s) = 0.60) was shown between the gill MDA contents and exposure time. This study illustrates oxyradical scavenger GPx best correlated with stress level of pollutants among the various antioxidant parameters.

Enormous PCBs increase in oysters from the coast of Guangdong, China.

PCBs equivalent to Aroclor 1242 and 1254 in soft tissues of oysters Crassostrea rivularis from the Guangdong coast, China, were measured using a GC-ECD. PCB concentrations (ng g(-1)d.w.) ranged from 30 to 2040 with an average of 315 in 2003-2007, and 0.35-1.43 with an average of 0.56 in 1989-1991. Annual averages were 0.61, 0.65, 313, 290 and 342ng g(-1), respectively in 1989, 1991, 2003, 2006 and 2007. In east Guangdong, the Pearl River Estuary, and west Guangdong, regional means were 444, 273, 194ng g(-1), respectively in 2003-2007, and 0.43, 0.78, 0.38ng g(-1), respectively in 1989-1991, indicating PCB levels in oysters have risen greatly by ratios of 350-1032 compared with earlier data. PCB sources may derive from older transformers, printing materials and pressworks. Fortunately, current residual PCBs in the oysters were 0.004-0.253mg kg(-1) (w.w.), still below hygienic criteria of China and developed countries.

[Risk assessment of coastal ecosystem in Beibu Gulf, Guangxi of South China].

Based on the marine ecological investigation in the coastal area of Beibu Gulf, Guangxi in September 2009, a GIS-based evaluation was conducted on the present status of ecological environment quality, including seawater quality, nutrient level, biomass, primary productivity, biodiversity, and ecological buffer capacity, in the area in autumn, and the integrated ecological risk index (ERI) was adopted to assess the risk of the coastal ecosystem in the Gulf. In September 2009, the study area had a better ecological environment quality. Most of the risk indicators were at medium or lower level, and the total area was overall at low ecological risk level. The ERI showed that there was an obvious spatial heterogeneity in the distribution of the ecological risk. The nearer to the harbors, the higher the risk was.

[Accumulation and release characteristics of heavy metals in Crassostrea rivalaris under mixed exposure].

With a mixed solution of lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), chromium (Cr), mercury (Hg) and arsenic (As), this paper studied the accumulation and release characteristics of test heavy metals in Crassostrea rivalaris. The results showed that C. rivalaris had a strong ability to accumulate Pb, Cu, Ni, Cd, Cr and Hg, being able to indicate the concentration levels of these heavy metals in solution, but a weak ability to accumulate Zn and As. In the following 35 days release stage, no significant change was observed in the contents of test heavy metals in C. rivalaris, suggesting that C. rivalaris had weak ability to release heavy metals. Two-compartment kinetic model could well fit the accumulation of heavy metals in C. rivalaris, but failed in simulating their release characteristics.