Polycyclic aromatic hydrocarbons (PAHs) have been reported to absorb ultraviolet (UV) light, resulting in enhanced toxicity. Early developmental stages of bivalves may be particularly susceptible to photo-enhanced toxicity during oil spills. In the current study, toxicity tests were conducted with sperm and three larval ages of the eastern oyster (Crassostrea virginica) to evaluate the photo-enhanced toxicity of low-energy water-accommodated fractions (WAFs) of two weathered Macondo crude oils collected from the Deepwater Horizon incident. Larvae exposed to oil WAFs under UV-filtered light demonstrated consistently higher survival and normal development than larvae exposed to WAFs under UV light. The phototoxicity of weathered Macondo oil increased as a function of increasing UV light intensity and dose. Early developing oyster larvae were the most sensitive to photo-enhanced toxicity, whereas later shelled prodissoconch larvae were insensitive. Comparisons between two weathered crude oils demonstrated that toxicity was dependent on phototoxic PAH concentration and UV light intensity.

In order to evaluate the main source of nutrients for maintaining the high production in shellfish farming bay, we have measured 222Rn activities and the concentrations of nutrients in stream water, seawater, and coastal groundwater around Geoje Bay, one of the largest cultivation areas of oyster in the southern sea of Korea in April 2013. Using the 222Rn and Si mass balance model, the residence time of bay seawater was about 5days and the submarine groundwater discharge (SGD) into the bay was estimated to be approximately 1.8×106m3 d−1. The SGD-derived nutrient fluxes contributed approximately 54% for DIN, 5% for DIP, and 50% for DSi of total nutrient input entering into the bay. Thus, our results suggest that SGD is the major source of nutrients in Geoje Bay, and SGD-derived nutrients are very important to support the biological production of this shellfish farming bay.

The present study deals with the investigation of existing pollution levels and potential ecological risk assessment of endocrine-disrupting organochlorine and organophosphorous pesticide residues in the Vasai Creek water near Mumbai. The average concentration of α- and β-endosulfan (137.75ng·L−1) exceeds the chronic criteria level of α- and β-endosulfan (6.5ng·L−1) set by US EPA for freshwater aquatic organisms. The concentration levels of aldrin (75.31ng·L−1), dieldrin (71.19ng·L−1) and endrin (76.60ng·L−1) was found to exceed the respective criteria levels of <0.13, 65.1, and 61ng·L−1 as set by US EPA for protection of freshwater aquatic organisms. In addition, the level of chlorpyrifos (208.77ng·L−1) exceeds the recommended concentration value of <35ng·L−1 set by Ministry of Environment of British Colombia. The results of our study give an indication of probable ecotoxicological risk to the marine breeding organisms of creek.

Limited information is available on mercury (Hg) levels in various shark species consumed in Korea. The methyl-Hg (Me-Hg) and total Hg concentrations in all shark species ranged from 0.08 to 4.5 (mean: 1.2) mg/kg wet weight and from 0.1 to 7.0 (mean: 1.4) mg/kg wet weight, respectively. Inter-species differences in Hg accumulation were found among the species; however, Hg accumulation was homogenous between dorsal and pectoral fins within species. The highest Hg levels were found in aggressive carnivore shark species. Trophic position was important in determining Hg accumulation for aggressive carnivore sharks. Approximately 80% of shark species exceeded the safety limits for Me-Hg established by domestic and international authorities. The mean estimated daily intake of Me-Hg (1.3μg/kg body weight/day) for Korean populations consuming various sharks was higher than the guidelines proposed by international regulatory authorities, suggesting that excessive shark fin consumption may pose potential health risks for Koreans.

Veterinary antibiotics are emerging contaminants of concern. A total of 139 samples comprising 104 marine sediments and 35 estuarine sediments were collected from the Bohai Sea area and analyzed for seventeen antibiotics. The results reveal that the presence and concentration of antibiotics were generally higher in the estuaries than in the sea. The highest antibiotic concentration, 4695μgkg−1 of oxytetracycline, occurred in the estuarine sediment from Ziya New River. Bohai Bay and Laizhou Bay and the surrounding estuaries had higher concentrations of antibiotics. However, low levels of antibiotics detected were detected in Liaodong Bay in contrast to the high concentrations present in the surrounding estuaries. Spatial heterogeneity and principal component analysis suggest a large impact of terrestrial sources of the antibiotics contaminating the Bohai Sea. Risk quotients indicate that current levels of norfloxacin and oxytetracycline might be potentially hazardous to sensitive biota both in the Bohai Sea and in its surrounding estuaries.

In this study, seawater quality measurements, including salinity, sea surface temperature (SST), chlorophyll-a (Chl-a), Secchi disk depth (SDD), pH, and dissolved oxygen (DO), were made from June 2013 to November 2014 at 52 stations in the southeastern Arabian Gulf. Significant variability was noticed for all collected parameters. Salinity showed a decreasing trend, and Chl-a, DO, pH, and SDD demonstrated increasing trends from shallow onshore stations to deep offshore ones, which could be attributed to variations of ocean circulation and meteorological conditions from onshore to offshore waters, and the likely effects of desalination plants along the coast. Salinity and temperature were high in summer and low in winter while Chl-a, SDD, pH, and DO indicated an opposite trend. The CTD profiles showed vertically well-mixed structures. Qualitative analysis of phytoplankton showed a high diversity of species without anomalous species found except in Ras Al Khaimah stations where diatoms were the dominating ones.

The spatial variation, possible sources and ecological risk of polychlorinated biphenyls (PCBs) in the sediment from the Songhua River, China were investigated and evaluated in this paper. The total concentration of PCBs ranged from 0.59 to 12.38ng/gdw, with a mean value of 3.82ng/gdw. The seven indicators of PCB concentrations are significantly correlated with the total PCB concentrations (R=0.950, p=0.000). The temporal trend of PCBs in sediments showed that the total PCBs in the Songhua River have decreased since 2008. Point source pollution, discharge of historical usage and industrial sewage, and emissions of unintentionally produced PCBs were the predominant sources in sediment. A risk assessment indicated that most of the sampling sites in the sediment were at low potential ecological risk. The apparent decrease of PCBs in the sediment appeared after the China National Coordination Group for Implementation of the Stockholm Convention was established. A conceptual reverse management framework for PCBs and other organic pollutants was established in this study.

There is an increasing need to develop reliable methodologies for chronic toxicity testing using tropical species. The present work aimed at developing a suitable short-term chronic toxicity test with Mysidopsis juniae using zinc (Zn) and nickel (Ni) as model chemicals and growth (length and dry weight), survival, and egg production (number of females with eggs) as endpoints after seven days of exposure. Survival and growth of newborn M. juniae were affected by chronic exposure to zinc, while nickel affected only survival. For zinc, dry weight was the most sensitive endpoint with significant effects even at the lowest tested concentration (75μgZn·L−1), whereas for nickel, survival was the most sensitive parameter (LC20 of 26μgNi·L−1). Egg production was not affected. M. juniae short-term chronic testing is a sensitive approach to evaluating metal toxicity; further studies are necessary to assess chronic toxicity for others contaminants in the proposed assay.

Seagrass meadows in many parts of the globe are threatened by a range of processes including port development, dredging and land clearing in coastal catchments, which can reduce water clarity and increase sedimentation pressure. As rates of seagrass loss increase, there is an urgent need to understand the potential impacts of development on these critical species. This research compares the effects of shading and burial by fine sand on two seagrass species Zostera muelleri and Halophila ovalis in Port Curtis Bay, an industrial harbour located on the continental margin adjacent to the Great Barrier Reef Heritage Area, Australia. The research finds that shading in combination with burial causes a significant decline in growth rates in both species, but that burial ≥10mm reduces growth rates to a greater extent than shading. The paper concludes by discussing the implications of these findings for port management and impact assessment.

Two strains (Pseudomonas taiwanensis PYR1 and Acinetobacter baumannii INP1) were isolated from PAH-contaminated Liaohe estuarine wetland using enrichment. The cells of PYR1 and INP1 were immobilized in cinder beads for pyrene and indeno(1,2,3-cd)pyrene biodegradation in wetland. Biodegradation of pyrene and indeno(1,2,3-cd)pyrene in soils from wetland was carried out in pots using free cells as well as those immobilized in cinder beads to ascertain the role of bioaugmentation. Supported by the cinder beads, the immobilized cells degraded 70.7% and 80.9% of pyrene and indeno(1,2,3-cd)pyrene respectively after 30days. While the free cells degraded only 58.2% and 55.3%. Additionally, microbial analysis with high-throughput sequencing revealed the changes of microbial communities in soil without and with cinder beads immobilized with strains. The result indicated that Gammaproteobacteria were dominant PAH-degrading groups during bioaugmentation. This effective approach can be used to treat other PAH-contaminated wetlands by immobilizing different species of bacteria in cinder beads.