In this present study, petroleum hydrocarbons were statistically analyzed in three different coastal sediment cores viz., (N1, P1 and P2) from the Southeast coast of Tamil Nadu, India to examine the viability of PHCs. The significant positive relationship between mud (silt+clay+sand) and PHC unveiled that high specific surface of area of mud content raise the level of PHCs. Cluster analysis was used to discriminate the sediment samples based on their degree of contamination. The present study shows that instead of expensive and destructive PHC chemical methods, magnetic susceptibility is found to be a suitable, cheap and rapid method for detailed study of PHC in marine sediments. This baseline PHCs data can be used for regular ecological monitoring and effective management for the mining and tourism related activities in the coastal ecosystem.

Air pollution has become more serious in many developing countries. Heavy particulate matter (PM) air pollution is a major threat to people's respiratory and cardiopulmonary health. It is an important problem for public health research to accurately estimate the spatial distribution of high PM concentrations from a limited number of monitoring stations. In this study, a maximum entropy (MaxEnt) model was adopted to obtain the probability distribution map of high PM10 concentrations. Daily PM10 concentration data from 19 air quality monitoring stations from the years 2008–2011 were collected. Land cover, road density, and meteorological data were selected as explanatory variables entered in the model. A receiver operating characteristic (ROC) analysis was used to evaluate the performance of the MaxEnt model. The area under the ROC curve (AUC) shows that the MaxEnt model fits well in the four year period. AUC is 0.78 in 2008, 0.79 in 2009, 0.81 in 2010, and 0.80 in 2011. A probability distribution map of high PM10 concentration indicates high human health risks in regions of Beijing in areas with dense roads and buildings. During the entire research period from 2008 to 2011, the distribution of high PM10 concentration is relatively stable and it indicates that the trend of high concentration has not changed significantly during the four years. Traffic and land cover are the two most important factors that can explain more than 80% variance of PM10 from 2008 to 2011.

Plastic debris is ubiquitous in the marine environment and the world's shores represent a major sink. However, knowledge about plastic abundance in remote areas is scarce. Therefore, plastic abundance was investigated on a small island of the Maldives. Plastic debris (>1mm) was sampled once in natural long-term accumulation zones at the north shore and at the high tide drift line of the south shore on seven consecutive days to quantify daily plastic accumulation. Reliable identification of plastic debris was ensured by FTIR spectroscopy. Despite the remoteness of the island a considerable amount of plastic debris was present. At both sites a high variability in plastic abundance on a spatial and temporal scale was observed, which may be best explained by environmental factors. In addition, our results show that snapshot sampling may deliver biased results and indicate that future monitoring programs should consider spatial and temporal variation of plastic deposition.

Geochemical speciation of As, Cd, Co, Cr, Cu, Ni, Pb, V and Zn were determined in the surface sediments of the southern Caspian Sea. A five-step sequential extraction technique was used to determine the chemical forms of metals. Mean concentrations (ppm) of heavy metals were (mean±S.D.) As: 9.94±1.71, Cd: 0.87±0.23, Co: 14.85±2.80, Cr: 72.29±19.48, Cu: 18.91±4.48, Ni: 32.87±5.25, Pb: 12.48±3.22, V: 86.07±20.71 and Zn: 66.85±10.11. Among the metals, Cu, As, Pb and Zn exhibited relatively higher mobility, while Cd, Co, Cr, Ni and V were found mainly in the residual fractions. Cu and As showed the highest percentages in the exchangeable phase while Co and Cr had the lowest percentages in the phase. The Risk Assessment Code (RAC) values indicated that As, Cu and V had medium risk at some sampling sites. According to pollution load index (PLI), sediments from some sampling sites were polluted.

Variable and occasionally high concentrations of cadmium in wild oysters at a remote location with the potential to develop aquaculture enterprises motivated research into the distribution and sources of metals in oysters, seawater, sediment, suspended solids and phytoplankton.Saccostrea mytiloides and Saccostrea mordax contained cadmium concentrations exceeding the food standard maximum level (ML) at three of four sites. At one site with high zinc levels in sediment, oyster cadmium levels were below the ML. Metal levels in seawater were not correlated with cadmium levels in oysters but high cadmium/zinc ratios were measured in Trichodesmium erythraeum blooms.We suggest that oysters accumulate cadmium mainly from annual phytoplankton blooms except at sites where zinc availability is sufficiently high to prevent uptake though a mechanism of antagonistic exclusion. Knowledge of the source and uptake mechanisms of cadmium in oysters should lead to new management strategies to reduce cadmium levels in farmed oysters.

Fifty two surface sediments were collected from the northern part of the Gulf of Mannar biosphere reserve to assess the geospatial risk of sediments. We found that distribution of organic matter and CaCO3 distributions were locally controlled by the mangrove litters and fragmented coral debris. In addition, Fe and Mn concentrations in the marine sediments were probably supplied through the riverine input and natural processes. The Geo-accumulation of elements fall under the uncontaminated category except Pb. Lead show a wide range of contamination from uncontaminated-moderately contaminated to extremely contaminated category. The sediment toxicity level of the elements revealed that the majority of the sediments fall under moderately to highly polluted sediments (23.07–28.84%). The grades of potential ecological risk suggest that predominant sediments fall under low to moderate risk category (55.7–32.7%). The accumulation level of trace elements clearly suggests that the coral reef ecosystem is under low to moderate risk.

According to 2014–2016 monitoring data, an assessment index system including water quality, depositional environment and ecosystem was built to evaluate the health statue of marine ecosystem in the Laizhou Bay using analytic hierarchy process (AHP) method. The results, spatialized in ArcGIS software, show: while the comprehensive ecological health index is 0.62, the ecological environmental quality in the Laizhou Bay is in a sub-healthy state; the unhealthy area is mainly concentrated in southwestern inshore region, and impacted by serious environmental problems, such as water eutrophication and heavy metal pollution; the northwestern and southeastern inshore regions are in a sub-healthy state, while the eastern inshore and northern areas are in the healthiest state. The land-based pollutants that discharge into the sea may be the leading factors that are causing ecological environment deterioration in the Laizhou Bay, and the reclamation work ongoing around the port has exacerbated the ecological risk.

The main aim of study was to develop the environmental quality standards (EQSMP) for selected heavy metals: Pb, Cd, Hg and Ni bioaccumulated in the tissues of marine macrophytobenthic plants: Chara baltica, Cladophora spp., Coccotylus truncatus, Furcellaria lumbricalis, Polysiphonia fucoides, Stuckenia pectinata and Zanichellia palustris, collected in designated areas of the southern Baltic Sea in period 2008–2015. The calculated concentration ratios (CR), which attained very high values: 104Lkg−1 for lead, 103Lkg−1 for nickel and mercury and even 105Lkg−1 for cadmium formed the basis for the determination of EQSMP values. The EQSMP values were: 26mgkg−1d.w. for Pb, 33mgkg−1d.w. for Cd, 32mgkg−1d.w. for Ni and 0.4mgkg−1d.w. for Hg. The application of macrophytobenthic plants as bioindicators in marine environment status assessment of certain areas of the Baltic Sea is also described in the paper.

The coastal seagrass meadows in the Townsville region of the Great Barrier Reef are crucial seagrass foraging habitat for endangered dugong populations. Deteriorating coastal water quality and in situ light levels reduce the extent of these meadows, particularly in years with significant terrestrial runoff from the nearby Burdekin River catchment. However, uncertainty surrounds the impact of variable seagrass abundance on dugong carrying capacity. Here, I demonstrate that a power-law relationship with exponent value of −1 (R2~0.87) links mortality data with predicted changes in annual above ground seagrass biomass. This relationship indicates that the dugong carrying capacity of the region is tightly coupled to the biomass of seagrass available for metabolism. Thus, mortality rates increase precipitously following large flood events with a response lag of <12-months. The management implications of this result are discussed in terms of climate scenarios that indicate an increased future likelihood of extreme flood events.

Identifying the main sources of nutrient loading is a key factor for efficient mitigation of eutrophication. This study has investigated the pathways of external nutrient loading to 656 coastal water bodies along the entire Swedish coastline. The studied water bodies have been delineated to meet requirements in the European Union's Water Framework Directive, and recent status assessments have shown that 57% of them fail to attain good or high ecological status with respect to nutrients. The analysis in the study was performed on data from mass-balance based nutrient budgets computed using the modelling framework Vattenwebb. The external nutrient contribution from the sea to the water bodies was highly variable, ranging from about 1% to nearly 100%, but the median contribution was >99% of the total external loading regarding both nitrogen and phosphorus. External loading from the atmosphere and local catchment area played a minor role in general. However, 45 coastal water bodies received >25% of the external nitrogen and phosphorus from their catchments. Loading from land typically peaked in April following ice-break and snow melting and was comparatively low during summer. The results indicate that for many eutrophicated Swedish coastal water bodies, nutrient abatement is likely to be optimally effective when potential measures in all of the catchment area of the concerned sea basin are considered. Local-scale mitigation in single water bodies will likely be locally effective only in the small proportion of areas where water and thereby also nutrient input from the catchment is high compared to the influx from the sea. Future studies should include nutrient reduction scenarios in order to refine these conclusions and to identify relevant spatial scales for coastal eutrophication mitigation measures from a water body perspective.