Marine and coastal ecosystems are among the largest contributors to the Earth's productivity. Experimental studies have shown negative impacts of microplastics on individual algae or zooplankton organisms. Consequently, primary and secondary productivity may be negatively affected as well. In this study we attempted to estimate the impacts on productivity at ecosystem level based on reported laboratory findings with a modelling approach, using our biogeochemical model for the North Sea (Delft3D-GEM). Although the model predicted that microplastics do not affect the total primary or secondary production of the North Sea as a whole, the spatial patterns of secondary production were altered, showing local changes of ±10%. However, relevant field data on microplastics are scarce, and strong assumptions were required to include the plastic concentrations and their impacts under field conditions into the model. These assumptions reveal the main knowledge gaps that have to be resolved to improve the first estimate above.

Five heavy metals/metalloids and related potential health risks were investigated in three commercially important fish species (Anodontostoma chacunda, Belangerii, and Cynoglossurs arel) in Musa Estuary and Mahshahr Harbour of the Persian Gulf. A total of 116 fish samples were collected, and their liver and muscle organs were separately analyzed using ICP-MS. Results revealed that studied metals concentrations (with some exceptions) varied among sampling stations, fish species and their organs. Human health risk is evaluated using different indices. The results indicated that arsenic and mercury are the most hazardous elements. Estimated daily intake (EDI) for the metals exceeded the provisional tolerable daily intake (PTDI) for all studied fish species. Also, target risk (TR) of arsenic indicated that consumption over a long period of time may result in a carcinogenic effect. The results are expected to create awareness among the public on the safety of consuming food products grown in particular areas.

We investigated the bioavailability, mobility, and origin of heavy metals present in sediments from the Anzali Wetland. Chemical speciation of the metals was performed according to the Tessier method. Results indicated that Cd and As showed the highest level of bioavailability, whereas Cr showed the lowest level. Cr, Co, and V were shown to have a terrestrial origin. The metal As was mostly found in the reducible fraction (F3), whereas other metals were highest in the residual phase. The levels of Co present in the oxidizable fraction (F4); Pb and Cd present in the carbonate fraction (F2); and the other metals present in the exchangeable fraction (F1) were found to be the lowest. On the basis of the Risk Assessment Code of metals, Cd at most stations, As and Ni at some stations, and Zn at one station revealed to have a moderate risk. Co and Pb were found to have a low risk at all stations. Considering Pollution Load Index, stations 2 and 3 were classified as moderately polluted and the remaining stations were unpolluted. As suggested by enrichment factor analysis, As was moderately enriched and other metals had a deficiency to minimal enrichment at all the stations.

Oil spill accidents occur with increasing frequency in the Chinese Bohai Sea because of the presence of extensive number of oil platforms and oil pipelines the Chinese Bohai region. An appropriate risk assessment for oil spill prevention and readiness is necessary. Risk assessment for the entire Chinese Bohai Sea based on a quantitative method is proposed. We created a hypothetical simulation of oil spill trajectories based on an oil spill model for 28 oil platforms in the Chinese Bohai region in 2010. Then, we mapped a risk index in the study areas based on a combination of oil spill trajectories and shoreline susceptibility data. Five high-risk areas were identified in the entire Chinese Bohai Sea. Detailed suggestions for prevention and readiness are described here. These results can help in developing a risk assessment of oil spills in the Chinese Bohai Sea and serve as a useful analytic tool for slick-related emergencies.

China's rapid economic and social development has led to an acceleration in nutrient inputs to coastal waters, which, in turn, has resulted in severe coastal eutrophication. On the occasion of the 40th anniversary of China's reform and opening up, the evolution of the causative factors and the state as well as future prospects for coastal eutrophication in the China Seas are analyzed and summarized. Results showed that the coastal eutrophication situation was not so serious at the beginning of reform and opening up, but it worsened rapidly from the end of the 1980s to the mid-2000s. In the last decade, the worsening trend has been curbed but the status of coastal eutrophication has not been substantially improved. Much work is still needed to be able control the total amount of nutrients entering coastal waters and enable comprehensive treatment of coastal eutrophication in the China Seas.

Our study evaluated heavy metal concentrations in soft tissues of sea hare, Aplysia fasciata, from the Lower Laguna Madre, Texas. Heavy metals in tissues followed Se>As>Pb>Cd. Concentrations ranged As (BDL-28.08), Cd (BDL-5.50), Pb (BDL-12.85) and Se (4.25–93.43ppm). Median As, Cd, Pb, and Se tissue levels exceeded exposure levels. Significant relationships occurred in metal-metal (AsCd, AsPb, CdPb, CdSe, and PbSe), metal-tissue (significant Se uptake by inhalant and exhalant siphons and As in the hepatopancreas), and metal-metal within tissue (AsPb in the hepatopancreas and CdPb in the digestive cecum) analyses (p<0.05). Bioaccumulation factors (BAF) suggested the inhalant siphon, hepatopancreas, and digestive cecum function as macroconcentrators of Cd, hepatopancreas and digestive cecum as macroconcentrators of Pb, and all tissues were deconcentrators for As and Se. As a bioaccumulator of heavy metals, Aplysia was evaluated as a bioindicator of marine pollution in harbors and bays.

Microplastics and sulfamethoxazole coexist ubiquitously in the marine environment, and microplastics tend to sorb organic pollutants from the surrounding environment. Here, the sorption kinetics and isotherms of sulfamethoxazole on polyethylene (PE) microplastics closely fitted a pseudo-second-order model (R2 = 0.98) and linear model (R2 = 0.99), respectively, indicating that the sorption process was partition-dominant interaction. The main binding mechanism was possibly the van der Waals interaction for hydrophilic sulfamethoxazole onto hydrophobic PE microplastics. The effects of pH, dissolved organic matter and salinity on sorption behavior were also studied. The sorption behavior of sulfamethoxazole on PE microplastics was not significantly influenced by pH and salinity, probably because the electrostatic repulsion played a minor role. In addition, the negligible effect of dissolved organic matter was attributed to the greater affinity of sulfamethoxazole to PE microplastics than to dissolved organic matter. Our results demonstrated that PE microplastics may serve as a carrier for sulfamethoxazole in the aquatic environment.

Spatial patterns in perfluoroalkyl substances were quantified for exploited fish and crustaceans across two contrasting Australian estuaries (Port Stephens and Hunter River). Perfluorooctane sulfonate (PFOS) was detected in 77% of composites from Port Stephens and 100% of composites from Hunter River. Most species from Port Stephens showed a clear trend with distance to source. In contrast, only a subset of species showed this trend in the Hunter River, potentially due to species movement patterns and differing hydrology. Spatial modelling showed that PFOS concentrations were expected to exceed the relevant trigger value up to ~13,500 m from the main point source for Port Stephens and ~9000 m for the Hunter River. These results represent the first major investigation of bioaccumulation of PFASs in exploited species in Australian estuaries, and highlight various factors that can contribute to spatial patterns in bioaccumulation.