A geographically extensive investigation was carried out to analyze the concentrations of heavy metals, PCBs and OCPs in the sediments and marine organisms collected from the Liaohe Estuary. In order to determine the spatial distribution and potential ecological risk of heavy metals, the surface sediments were collected from 44 sites in the Liaohe Estuary. The results showed that the heavy metal contents in the sediments were observed in the following order: Cr (11.2–84.8mg/kg)>Cu (1.7–47.9mg/kg)>Pb (4.3–28.3mg/kg)>As (1.61–12.77mg/kg)>Cd (0.06–0.47mg/kg)>Hg (0.005–0.113mg/kg). In comparison with the concentrations of heavy metals and POPs in other regions, the concentrations of As, Pb and DDTs in the Liaohe Estuary were generally low, and other pollutant concentrations were inconsistent with those reported in other regions. The contamination factor (CF), the pollution load index (PLI), the geoaccumulation index and the potential ecological risk index were used to analyze the pollution situation, which showed that the heavy metal pollution in Liaohe Estuary is mainly dominated by Cd and Hg. The concentrations of the four heavy metals varied significantly in the three kinds of tested organisms (fish, mollusk and crustacean), indicating the different accumulative abilities of the species. The results obtained in this study provide useful information background information for further ecology investigation and management in this region.

Sewage effluent input and population were chosen as predictors of microplastic presence in sediments at four sites in the River Thames basin (UK). Large microplastic particles (1mm–4mm) were extracted using a stepwise approach to include visual extraction, flotation and identification using Raman spectroscopy. Microplastics were found at all four sites. One site had significantly higher numbers of microplastics than other sites, average 66 particles 100g−1, 91% of which were fragments. This site was downstream of a storm drain outfall receiving urban runoff; many of the fragments at this site were determined to be derived of thermoplastic road-surface marking paints. At the remaining three sites, fibres were the dominant particle type. The most common polymers identified included polypropylene, polyester and polyarylsulphone. This study describes two major new findings: presence of microplastic particles in a UK freshwater system and identification of road marking paints as a source of microplastics.This study is the first to quantify microplastics of any size in river sediments in the UK and links their presence to terrestrial sources including sewage and road marking paints.

Mercury (Hg) can reach the environment through natural and human-related sources, threatening ecosystems all over the planet due to its well known deleterious effects. Therefore, Antarctic trophic webs, despite being relatively isolated, are not exempt of its influence. To evaluate Hg concentrations in an Antarctic ecosystem, different tissues from 2 species of invertebrates, 2 of fish, 8 of birds, 4 of pinnipeds and at least 5 of vegetation were investigated (n=176). For animals, values ranged from 0.018 to 48.7μgg−1 dw (whole Antarctic krill and Antarctic Fur Seal liver). They were generally correlated to trophic position (assessed by δ15N and δ13C) but also to cephalopods and myctophids consumption. For vegetation, values ranged from 0.014 to 0.227μgg−1 dw (Colobanthus quitensis and an unidentified lichen), with lichens presenting significantly higher values than mosses, likely due to year-round exposure and absorption of animal derived organic matter, as hypothesized by literature.

This study is an attempt to explore the effectiveness of satellite data in predicting hourly PM2.5 (Respirable particulate matter with aerodynamic diameter below 2.5 μm) concentrations for a chosen number of forward time steps over eastern China. MODIS (Moderate Resolution Imaging Spectroradiometer) aerosol optical depth (AOD), hourly forecasted meteorological variables, along with respective pollutant predictors from 2013 to 2015 were used as input to a multi-layer perceptron (MLP) type of back-propagation neural network. A novel approach, based on the correlation coefficients between surface PM2.5 and meteorological variables, was employed in selecting the averaging periods for meteorological input. Backward air mass trajectory was combined with AOD so as to explicitly measure the contribution of regional transport. Owing to the spatial variability of the AOD-PM2.5 relationship, each grid cell on the AOD retrievals was assigned to a prediction model trained by the nearest monitoring station from them. The proposed model seems to perform better in southern China. Also predictions incorporating transport predictor tend to have higher rates of detecting PM2.5 exceedance hours. We further introduced a sensitive analysis in Beijing by testing a model with surface PM2.5 input, evaluated versus the AOD input one. The two models were evaluated on the perturbed test set with input values ranging from 10 to 40%. It is found that PM model significantly outperforms the AOD one when the prediction horizon is longer than 36 h. This approach shows potential to be adapted for other regions, but will be most useful for areas without access to sophisticated deterministic models.

Particulate matter (PM10) is the pollutant causing exceedances of ambient air quality thresholds, and the key indicator of air quality index in Brunei Darussalam for haze related episodes caused by the recurrent biomass fires in Southeast Asia. The present study aims at providing suitable forecasts for PM10 exceedances to aid in health advisory during haze episodes at the four administrative districts of the country. A framework based on random forests (RFs), genetic algorithm (GA) and back propagation neural networks (BPNN) computational intelligence techniques has been proposed in which the final prediction is made by the BPNN model. A hybrid combination of GA and RFs is initially applied to determine optimal set of inputs from the initial data sets of largely available meteorological, persistency of high pollution levels, short and long term variations of emissions rates parameters. The inputs selection procedure does not depend on the back propagation training algorithm. The numerical results presented in this paper show that the proposed model not only produced satisfactory forecasts but also consistently performed better via several statistical performance indicators when compared with the standard BPNN and GA optimisation based on back propagation training algorithm. The model also showed satisfactory threshold exceedances forecasts achieving for instance best true predicted rate of 0.800, false positive rate of 0.014, false alarm rate of 0.333 and success index of 0.786 at Brunei-Muara district monitoring station. Overall, the current study has profound implications on future studies to develop a real-time air quality forecasting system to support haze management.

Plastic pollution in the marine environment attracts much attention from both researchers and the general public. Plastic items and other debris are commonly observed everywhere in the ocean, from the surface down to the deep ocean floor. In this study, we analysed 45.2km of video footage, collected during 56 transects surveying the seafloor of the Faial-Pico Passage in order to quantify the abundance of marine litter and its interactions with benthic fauna. The footage was collected by a Remotely Operated Vehicle (ROV) and a manned submersible at depths ranging between 40 and 525m. The mean litter density in the passage was 0.26±0.03 items·100m−1 (±SE) and was significantly higher between 151 and 250m compared to other depth strata. Overall, derelict fishing gear, mostly made of plastic, were the most common objects found on the seafloor, representing 64% of all items. Although we observed few evidence of direct deleterious effects by the litter, interactions with fauna were observed in more than half of the items. This study makes an important contribution in quantifying the abundance of marine litter on the seafloor of the Azores. The location of the Faial-Pico Passage, close to shore, makes it an appropriate site for long-term monitoring of litter on the seafloor and evaluate the efficiency of upcoming public policies aimed at reducing litter input into the oceans.

Heavy metals (Cu, Pb, Cr, Cd and As) contents in surface sediments from western Laizhou Bay were analysed to evaluate the spatial distribution pattern and their contamination level. As was mainly concentrated in the coastal area near the estuaries and the other metals were mainly concentrated in the central part of the study area. The heavy metals were present at unpolluted levels overall evaluated by the sediment quality guidelines and geoaccumulation index. Principal component analysis suggest that Cu, Pb and Cd were mainly sourced from natural processes and As was mainly derived from anthropogenic inputs. Meanwhile, Cr originated from both natural processes and anthropogenic contributions. Tidal currents, sediments and human activities were important factors affecting the distribution of heavy metals. The heavy metal environment was divided into four subareas to provide a reference for understanding the distribution and pollution of heavy metals in the estuary-bay system.

The present study aimed to use primary liver cell culture derived from the orange-spotted grouper, Epinephelus coioides, to assess the toxic effects of nonylphenol (NP) on the hepatocyte viability and the liver antioxidant system. E. coioides was selected due to its commercial importance. NP was used in this study because of its high potential of producing oxidative stress due to increased reactive oxygen species (ROS). A liver of E. coioides was digested with PBS containing 0.1% collagenase IV. The digested cells were moved to Leibovitz L-15 culture medium with 20% fetal bovine serum (FBS), 100IUmL−1 penicillin, 100μgmL−1 streptomycin. Aliquots of cell suspension were seeded as a monolayer into sterile 25cm2 tissue culture flasks and incubated at 30°C for 14days. The medium, containing non-attached cells, was removed after 24 to 48h and a new medium was added. The IC50 of 10−4molL−1 was determined for nonylphenol using MTT assay. Cells were then incubated with L-15 medium containing 10−5, 2×10−5, 3×10−5molL−1 of NP and samples were taken after 6, 12 and 24h of incubation for analysis of LPO, SOD, CAT, GPx, LDH, AST, ALT, and ALP. Based on the results, the lowest concentration of NP was not markedly cytotoxic to primary hepatocytes and the cell sensitivity to NP increased dose-dependently. The activities of SOD, CAT and GPx decreased significantly, while activities of LPO, LDH, AST, ALT and ALP, increased significantly in a dose-related pattern in NP-treated cells. In conclusion, this study revealed that NP could induce the oxidative stress in cultivated hepatocytes of E. coioides during a short-term exposure. NP toxicity is mainly due to the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Water accumulating in the bottom of ships (bilge water), contains a mixture of oil, detergents and other compounds from on board activities. To evaluate ecological effects of released bilge water the chemical composition and toxicity of treated bilge water from seven passenger ships was analysed. The oil content was below 15mgL−1, the threshold for legal discharge, in all but one ship. Still, significant reductions in feeding and reproduction of Acartia tonsa were found after 48h exposure in dilutions with 2.5–5% of bilge water. Mortality was significant at dilutions of 5–10% in 4 of the 5 bilge water samples. Surfactants were the most significant contributor to the toxicity on copepod vital rates and survival. Toxicity was also tested with Microtox where an EC50 was found at dilutions between 4.3% and 52%. The results show that ecological effects might occur also in diluted suspensions of bilge water.

This study aimed to determine the role of mangroves as a biofilter of heavy metals. The concentrations of heavy metals, namely copper, mercury, cadmium, zinc, and lead, in the mangroves Rhizophora apiculata, Ceriops tagal, Bruguiera gymnorrhiza, Lumnitzera racemosa, Xylocarpus granatum, Sonneratia alba, and Bruguiera parviflora at RAWN Park were determined using a Flame atomic absorption spectrophotometer. High concentrations of Cu (83.85μgg−1) and Hg (0.52μgg−1) were found in the tissues of L. racemosa, while high concentrations of Cd (10.81μgg−1), Zn (70.41μgg−1), and Pb (1.36μgg−1) were found in the tissues of B. gymnorrhiza, B. parviflora and C. tagal, respectively. The translocation and bioaccumulation factors of heavy metals by mangroves showed a variety of trends, which indicated the different partitioning and uptake capability of heavy metals in the tissues of various mangrove species. Thus, maintaining high diversity of mangroves is crucial to ensure the health and productivity of coastal zones.