This review of 19 chemical approaches used in assessing sediment quality are classified into empirical, mechanistic and sediment quality indices (SQI) groups. Empirical sediment quality guidelines (SQGs), based on matching chemical and biological-effects data and the mechanistic techniques, founded on equilibrium partitioning principals (EqP), are well established and most used. Empirical SQGs provide a useful screening tool to initially identify locations and chemicals of most concern, but are not regulatory criteria. The EqP approach is causally linked however, the scheme assumes porewater chemistry largely controls sediment toxicity. SQIs are not based on matching chemical-biological data and combine schemes with multiple narrative intents. The 41 SQGs reviewed show a considerable range in upper and lower guideline values. Grain size and organic content should be included into SQGs, however inclusion of suspended sediment into SQGs raises concerns. SQGs are built into decision-tree schemes with other lines-of-evidence and evaluated in a weight-of-evidence framework.

Coral communities are found at high latitude on the East Coast subtropical reefs of South Africa. They are biodiverse, economically important, and afforded World Heritage Site status in the iSimangaliso Wetland Park where some are subjected to recreational use. While the Park's unique coral reefs have, to date, suffered little bleaching from climate change, they are susceptible to the phenomenon and provide a natural laboratory for the study of its effects at high latitude. This review covers recent advances in the regional oceanography; coral community dynamics and the underpinning reef processes, including minor bleaching events; the incidence of coral disease; and coral genetic connectivity. The effects of human activity (SCUBA diving, recreational fishing, pesticide use) were assessed, as well as the nursery benefits of Acropora austera, a coral which provides the reefs with much structure and is vulnerable to damage and climate change. The reefs were valued in terms of human use as well as services such as sediment generation and retention. The results have provided valuable information on relatively pristine, high-latitude reefs, their socio-economic benefits, and the anticipated effects of climate change.

Five stations (≤250 m from the well heads) from three exploration wells of different ages from the SW Barents Sea were studied to investigate the spreading of drill cuttings and sediment quality. Two of the wells were drilled before the restriction of use of oil-based drilling fluids (1993). Elevated concentrations of Ba were found in sediments near all the wells with the highest concentrations at ≤60 m from the well head. The thickness of drill cutting layers was between >20 cm (well head) and 2 cm (250 m from the well head). The sediment quality varied from very bad (oldest well) to background (normal) (newer wells). Regulations led to better sediment quality. Metal concentrations from the oldest well suggested that the top 4 cm of the core represents sediment recovery. However, Ba concentrations of the top sediment layer at all the stations of the three wells indicate no physical recovery.

This study determined the quantity and diversity of microplastics in water and soft tissues of eastern oysters (Crassostrea virginica) and Atlantic mud crabs (Panopeus herbstii) in Mosquito Lagoon, a shallow, microtidal estuary along the east coast of central Florida. One-liter water samples had an average of 23.1 microplastic pieces (n = 15). Crabs (n = 90) had an average of 4.2 pieces in tissues/individual plus an average of 20.3 pieces/individual temporarily entangled in exposed surfaces and released within 5 days in tanks. Adult oysters (n = 90) had an average of 16.5 microplastic pieces/individual. Fibers, mostly royal/dark blue in color, dominated our collections. When compared per gram of tissue, crabs had two orders of magnitude more microplastic pieces than oysters. Our numbers were higher than previous studies on invertebrate microplastics; this is potentially the result of extensive urbanization, limited flushing, and intensive recreational usage of Mosquito Lagoon.

Although the presence of microplastics in marine biota has been widely recorded, extraction methods, method validation and approaches to monitoring are not standardized. In this study a method for microplastic extraction from fish guts based on a chemical alkaline digestion is presented. The average particle retrieval rate from spiked fish guts, used for method validation, was 84%. The weight and shape of the test particles (PET, PC, HD-PE) were also analysed with no noticeable changes in any particle shapes and only minor weight change in PET (2.63%). Microplastics were found in 1.8% of herrings (n=164) and in 0.9% of sprat (n=154). None of the three-spined sticklebacks (n=355) contained microplastic particles.

The gastrointestinal tract (GIT) of fish is a target of contaminants since it can absorb these substances. We evaluated the morphophysiological alterations in the GIT of Sphoeroides testudineus collected in two estuaries presenting differences in their environmental quality (NIA and IA). The intestine was analyzed for histological and neuronal changes; liver and gills for biochemical markers; muscle tissues for neurotoxicity and peripheral blood for genotoxic damage. The results showed alterations in the GIT of the animals collected in the IA, such as muscle tunica and goblet cell density reduction, increased intraepithelial lymphocytes density and changes in neuronal density. Furthermore, changes were observed in MTs and LPO in the gills. Thus, we suggest that TGI is functioning as a barrier that responds to ingested contaminants, in order to reduce their absorption and translocation. Thus, alterations in morphophysiological and enteric neurons in S. testudineus can be used as biomarkers of environmental contamination.

Surface sediments and clam Meretrix meretrix were collected from a northern estuarine region in Dongying City, China. Sediments were analysed for heavy metals (Hg, As, Cd, Cr, Cu, Pb, and Zn) and the clams were tested for metallothioneins (MTs) and lysosomal membrane stability (LMS). The heavy metal total concentrations decreased in the order of Cr>Zn>Cu>Pb>As>Cd>Hg. The results of Bureau Communautaire de Référence (BCR) sequential extraction of heavy metals showed that the geochemical speciation of all heavy metals was dominated by residual fraction. According to the responses of biomarkers in M. meretrix, the modified potential ecological risk index (PERI-B) can more accurately reflect heavy metals pollution. PERI-B showed all sediment samples have low or moderate risk, except at site S10 (considerable risk), and the main contribution of ecological risk heavy metals were Cd and Hg.

Thirty sediment samples from four different beaches along Bahia Solano and Nuquí (Department of Chocó) of eastern Colombia, with tourism and gold mining activities, were analysed to estimate the concentrations of fourteen different acid leachable metals. Metal distribution patterns showed elevated concentrations of Co, Cr, Cu, Pb and Zn compared with the upper continental crust values. Calculation of geochemical indices confirmed that the enrichment is due to periodic gold mining activities (severe to extremely severe enrichment of Cu, Zn, V, Co, Cr and Pb) along with natural (geological) contributions (minor and moderate enrichment of Ca, Mg, Fe, Ti, Mn and Li). Potential ecological risk index revealed that Pb posed the highest risk. Our results together with a global comparison suggest that the observed metal enrichments are mainly caused by mining and to a lesser extent by tourism in this region, thus instigating continuous monitoring of metal concentrations in this region.

Environmental contamination by mercury is a concern in marine food webs, and especially for large fish. We examined methylmercury (MeHg) levels in blood, muscle and liver of 35 individual Atlantic sturgeon (Acipenser oxyrhynchus), a commercially harvested, anadromous fish eastern Canada. Females had higher blood and liver MeHg levels than males, and in some tissues there was a suggestion of higher mercury in longer fish. Collectively, sturgeon MeHg levels were far below Canadian and international guidelines for safe consumption of fish meat.

After the Deepwater Horizon oil spill, a MOSSFA (Marine Oil Snow Sedimentation and Flocculent Accumulation) event took place, transporting an estimated 14% of total released oil to the sediment, and smothering parts of the benthic ecosystem. This microcosm study describes the effects of oiled artificial marine snow on benthic macroinvertebrates. Corophium volutator survival was reduced by 80% in oil-contaminated snow. Hydrobia ulvae survival was reduced by 40% in oil-contaminated snow, possibly due to consumption of oiled snow. Macoma balthica was sensitive to marine snow, addition of oil slightly decreased survival. This study reveals trait-dependent sensitivity to oil with or without marine snow. The main drivers for organismal response to marine snow and oil are motility, sensitivity to hypoxia and oil toxicity, and feeding habits. Adverse effects of MOSSFA events on benthos will have consequence for the benthic-pelagic habitat and food chain, and should receive more attention in oil spill management.