This study investigated the effects of 48h heavy metal exposure upon the metabolic profiles of Ruditapes decussatus and Ruditapes philippinarum using 1H NMR metabolomics. Both species were exposed to increasing concentrations of lead nitrate (10, 40, 60 and 100μg/L) and zinc chloride (20, 50, 100 and 150μg/L), under laboratory conditions. ICP-OES analysis was further performed on the clams' samples in order to verify the occurrence of heavy metal bioaccumulation. With respect to the controls, the metabolic profiles of treated R. decussatus exhibited higher levels of organic osmolytes and lower contents of free amino acids. An opposite behavior was shown by R. philippinarum. In terms of heavy metal, the exposure effects were more evident in the case of Pb rather than Zn. These findings show that NMR-based metabolomics has the required sensitivity and specificity for the identification of metabolites that can act as sensitive indicators of contaminant-induced stress.

Although relatively easy to extract in the marine environment, microplastics are very difficult to recover when they are trapped in sediments. The elutriation column is one of the best tools currently available for extracting plastics from sediment, but with a high sand recovery yield. This study aims to address the following questions: (i) is it possible to use a sedimentological approach to limit the sand recovery? (ii) does the extraction velocity of the sand and plastic particles vary according to density and granulometry? (iii) what is the relative recovery efficiency obtained for dense polymer particles mixed with marine sand? Based on a new granulometric classification, different plastic particle-size fractions are defined. Their extraction velocities are experimentally determined on particles of sediment and different plastics (PA, PVC). The particle recovery experiments indicate that it is possible to extract >90% of dense plastic particles in cases of negligible sand recovery.

Local sources of pollution can vary immensely on small geographic scales and short time frames due to differences in runoff and adjacent land use. This study examined the rate of uptake and retention of trace metals in Cassiopea maremetens, a benthic marine jellyfish, over a short time frame and in the presence of multiple pollutants. This study also validated the ability of C. maremetens to uptake metals in the field. Experimental manipulation demonstrated that metal accumulation in jellyfish tissue began within 24h of exposure to treated water and trended for higher accumulation in the presence of multiple pollutants. C. maremetens was found to uptake trace metals in the field and provide unique signatures among locations. This fine-scale detection and rapid accumulation of metals in jellyfish tissue can have major implications for both biomonitoring and the trophic transfer of pollutants through local ecosystems.

A total of 141 surface sediments were collected and analyzed for their geochemistry, total organic carbon, and grain size to assess the heavy metal pollution in the Bohai and Yellow Seas. The enrichment factor (EF) and geoaccumulation index (Igeo) of Cu, Pb, Zn, Cr, Cd, Ni, As, and Hg were calculated to assess anthropogenic contamination, and the results suggest that moderate Pb, Cd, and As contamination occurs in the study area. Sediment quality guidelines were applied to assess the adverse biological effects of these metals. The spatial distribution of the mean Effects Range-Median quotient for the vast majority of the study area is between 0.1 and 0.5, indicating low impact and potential negative biological effects. Multivariate analysis indicates that Cu, Pb, Zn, Cr, and Ni resulted primarily from lithogenic sources, whereas As, Cd, and Hg were mainly attributed to anthropogenic sources.

Floating litter in the estuarine system of Santos-São Vicente is common and is part of day-to-day activities of various users of the area. The objective of the present study was to carry out a quali-quantitative evaluation of the occurrence of floating litter, to infer their sources, and to identify environmental factors that are likely to control occurrence and distribution, with particular emphasis on the effects of tidal regimes. Six sampling stations were selected along the aforementioned estuary and visited monthly between July 2010 and January 2012. Floating litter was counted from a fixed sampling station. Plastics prevailed (89.64%) and their main source was domestic activities (55.41%). More litter was found during ebb spring tides, with higher concentrations obeying confluence patterns of the estuary's channels. Results indicated that occurrence can be attributed to the deficiency in basic sewage system in the area and the deliberate disposal into the estuary by the local population.

Finfish aquaculture can be installed over hard and patchy substrates where grab sampling is challenging and use of video can be an appropriate tool to document benthic changes. Video monitoring can show visual indicators of enrichment, namely flocculent matter, Beggiatoa-like mats, and opportunistic polychaete complexes (OPC). We examined factors influencing presence of indicators using 52 video monitoring reports collected in Newfoundland, Canada. The main driving factor was distance to cage, with indicators showing a higher probability of occurrence within 10m from cages due to low current velocities. Indicators were less prevalent on sites dominated by hard substrates while OPC in particular were restricted to depths >35m. Beggiatoa-like bacteria covered a larger surface than the two other indicators; however, our results suggest the necessity of amalgamating information related to all the indicators (including bare stations that could indicate anoxia) to establish a more accurate evaluation of aquaculture impact.

Assessing the health risk of PAHs in sediments was quite difficult because sediment occurred in sea floor, and it was very hard to contact with them directly for humans. This study was attempted to reveal the relationship between concentrations of PAHs in surface sediments and health risk of seafood consumers. The transfer (bioaccumulation) of PAHs from surface sediment into benthic organisms was predicted. Source contributions to PAHs and related toxicity and health risks (from intake of PAHs-contaminated benthic organisms) were studied based on PMF model and Monte Carlo simulation, respectively. Total concentrations of PAHs (TPAHs) ranged from 149.40 to 1211.97ngg−1 in sediments of Bohai Sea (BS), China. Petroleum and vehicular emission, coal combustion and coke oven constituted 40.0%, 32.2% and 27.8% of PAHs, respectively, but contributed 53.0%, 22.8% and 24.2% of toxicity posed by PAHs in sediment. For children, teens and adults, the 95th percentile carcinogenic and non-carcinogenic risks were below the threshold values of 10−6 and 1.0, respectively, suggesting no potential health risk. Sensitivity analysis suggested that exposure duration (ED) and PAH concentrations (CS) were the two most sensitive parameters in risk assessment. The results provided a method to evaluate the quality of sediments and the potential health risk related to PAHs in marine sediments.

Industrial pressures suffered by estuarine zones leave a pollution record in their sediment. Thus, high concentrations of many heavy metals and some organic compounds are often found in estuarine sediment. This work aims to contribute to the enhancement of water quality management strategies in these zones by studying in detail the diffusive processes that take place between the water and sediment using a two-pronged approach: experimental practice and numerical simulation. To provide an example of the practical application of the methodologies proposed in this paper, the Suances Estuary (northern Spain) was selected as the study zone. This estuary exhibits significant historical pollution and its sediment acts as a continuous internal source of zinc, mainly due to diffusive processes derived from the concentration gradient between the interstitial water at the solid particles of the sediment and the bottom of the water column. The experimentally obtained results, based on 6 case studies, demonstrated the buffering capacity of the system and allowed the determination of the required time for the mass transfer processes to reach an equilibrium state. Furthermore, the diffusion rate of zinc was approximately modeled taking into consideration the high concentration variability observed in sediment along the entire estuary. The convergence between the modeled and the experimental results indicated the required contact time to reach an equilibrium state in a real field situation.

Pre-spill background concentrations of TPH and PAH in water samples from the Gulf of Mexico are compared with samples (over 20,000) collected during and after the Deepwater Horizon incident (13,000 stations). Samples were collected by multiple response agencies, trustees and BP and reported in the Gulf Science Data. The samples were collected from a few m to over 800km in all directions from the wellhead. During the incident, samples with the highest concentrations of hydrocarbons were collected proximal to the wellhead or in samples collected from surface slicks and dispersant use. Of the 13,172 water sample TPH concentrations reported, 84% were below 1μg/L (background). Of the 16,557 water sample PAH concentrations reported, 79% were below 0.056μg/L (the median field blank, background). The percentage of samples below background increased rapidly after the well was capped. The spatial and temporal distributions of these hydrocarbon data are presented.

Total petroleum hydrocarbons, PAH and various trace metal residues were extracted and analyzed from fresh whole diamondback terrapin (Malaclemys terrapin) eggs, whole brackish-water gastropods (terrapin prey) and benthic sediment from anchialine pond environments in Bermuda inhabited by terrapins. Gastropods and terrapin eggs showed higher concentrations of trace metals and organic contaminants than sediments. Conversely, PAHs were mostly found within the sediment and smaller amounts detected in gastropods and terrapin eggs. Results indicated that contaminants in prey were transferred to terrapin eggs, and that concentrations of several contaminants exceeded potentially toxic concentrations for aquatic vertebrates. Necropsy of unhatched eggs from nests that had yielded viable hatchlings showed significantly compromised embryonic development. Bermudian diamondback terrapins reside and feed in brackish wetland habitats characterized by widespread, multifactorial contamination. This study suggests that environmental contamination plays a role in the recorded low hatching success in terrapin eggs in Bermuda.