The dynamics of three classes of organic contaminants, namely n-alkanes, polycyclic aromatic hydrocarbons and polychlorinated biphenyls, were evaluated from the settled suspended particulate matter (SPM) of two wastewater treatment plant outlets (O1 and O2) at the Marseille coast. We used a 1-m-high Plexiglas settling column filled with 7L of seawater to determine the particles' settling rates, size distribution, and the extent of organic contaminants. Six classes of SPM (50–200μm particles size) were obtained from 15 fractions of 500-mL successive filtering samples ranging from 30s to 5days, including those in the tube wall. The results of the experiment indicated that >68% of the particles settled within 15min, which highly correlated with the distribution of organic carbon and contaminant contents. Furthermore, we demonstrated that 9%–13% of the SPM, which contained 5%–11% of the organic contaminants, are non-settable even after 5days. Extrapolating such behaviour in situ using molecular diagnostic indices for organic contaminant source apportionment indicated that these non-settable contaminant particles are exported to the sea.

Heavy metals (Fe, Mn, Cr, Zn, Ni, Pb, Cu, Co and Cd) in the surface sediments of Cochin estuary, Southwest coast of India were analyzed to understand the spatio-temporal variation and contamination status via six sampling campaigns. Pollution indices like enrichment factor, geoaccumulation index and pollution load index inferred that the sediments of the northern arm of the estuary exhibited severe trace metal accumulation. Numerical sediment quality guidelines were applied to assess adverse biological effects of the trace metals, suggesting that occasional biological effect may occur due to Cr, Cu, Ni and Pb. Correlations between metals, organic carbon, silt and clay suggested that both fine grained sediment and organic matter were important carriers for these metals. Multivariate statistics indicated that the sources of Cu and Ni resulted primarily from natural weathering processes, whereas enriched levels of Cd, Cr, Zn and Pb were mainly attributed to anthropogenic activities.

We assessed inter-annual changes in fish assemblages of a tropical bay which experienced a heavily industrialized process in the last decades. A highly significant difference in community structure among the bay zones, and a decrease in fish richness and abundance over time were found. Changes in fish richness and abundance between the two first (1987–1988 and 1993–1995) and the two latter time periods (1998–2001 and 2012–2013) were sharpest in the inner bay zone, the most impacted bay area, and in the middle zone, whereas the outer zone remained comparatively stable over time. These changes coincided with increased metal pollution (mainly, Zn and Cd) in the bay and with the enlargement of the Sepetiba Port. Spatial changes in the fish community structure among the bay zones were related to differences in salinity, transparency and depth with this latter variable acting as a buffer stabilizing temporal community changes.

Plastic pollution is a major anthropogenic contaminant effecting the marine environment and is often associated with high human population densities and industrial activities. The microplastic (63 to 5000μm) burden of beach sediment and surf-zone water was investigated at selected sites along the entire length of the South African coastline. It was predicted that samples collected in areas of high population density, would contain a higher microplastic burden than those along coasts that demonstrate very low population densities. With the exception of water column microplastics within Richard's Bay Harbour (413.3±77.53particles·m−3) and Durban Harbour (1200±133.2particles·m−3), there were no significant spatial differences in microplastic loads. This supports the theory that harbours act as a source of microplastics for the surrounding marine environment. Additionally, the absence of any spatial variation highlights the possible long range distribution of microplastic pollutants by large scale ocean currents.

The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d < 100 nm) in the town Sisimiut and two nearby settlements, Sarfannguit and Itilleq, in West Greenland. Measurements were carried out during three weeks in April and May 2016. Air temperatures during the measurements ranged from −4.4 to +8.7 °C. A portable condensation particle counter (P-Trak) was used for the measurements. Results showed that the lowest concentrations were found during days with high wind speeds, with the lowest PNC average of 72 ± 11 cm−3 (n = 9) (12 m/s). Background concentrations were usually low compared to more densely populated countries, with a couple of exceptions, where there was no clear cause for elevated PNCs in a background area East of Sisimiut. Measured PNCs in the flue gas in the waste incineration plant in Sisimiut showed up to 334,976 cm−3 and are expected to be higher in the gas after it is released through the chimney. Average PNCs up to 77,009 ± 43,880 cm−3 (n = 26) were measured by a road located by the harbor in Sisimiut, while subsequent measurements at the same location showed much lower PNCs. The presence of heavy machinery elevated PNCs highly during two measurement events, giving PNCs up to 270,993 cm−3 but dropping to 1180 cm−3 10 min later, after the vehicle had passed by. A measurement event in Sisimiut Airport while an aircraft landed and departed showed an average PNC of 44,741 ± 85,094 cm−3 (n = 21). Two 24-h measurements resulted in average PNCs of 2960 ± 5704 cm−3 and 3935 ± 10,016 cm−3 respectively.

Mesel gold mine, Ratatotok Sub-district, North Sulawesi, Indonesia deposited about 4.5millionm3 of detoxified tailings containing arsenic (As) and mercury (Hg) via a submarine pipeline into Buyat Bay. As and Hg analysis of 216 fish muscle tissue composites from subsistence fishermen, local markets and a reference market confirmed that mean As levels were comparable between locations (range 1.71 to 2.12mg/kg wet weight (ww)) and <10% of the Australia New Zealand standard. Mean Hg concentrations were highest for the artisanal fishermen group (0.23mg/kg ww), similar between the local markets (0.11–0.14mg/kg ww) and lower at the reference market (0.04mg/kg ww). A 12-month fish availability study identified that the results were due to the different coral and deep ocean species assemblages. All mean values were <50% of the FAO/WHO/Codex standard for Hg. The results confirmed that there was no contamination from the deposited submarine tailings.

Ozone (O3) concentration, along with the concentrations of 10 precursors (acetone, toluene, ethylbenzene, benzene, xylenes, styrene, cyclohexane, NO, NO2, and CO), were measured and characterized at 16 locations in Riyadh, the capital city of Saudi Arabia, for the period of May through August 2012. The results showed that concentrations of all O3 precursors were high in central and industrial areas, owing mainly to road traffic volume and industrial emissions. Except for benzene, all pollutants featured a skewed distribution, which indicates that they might occasionally be influenced by contiguous sources of air pollution and/or by emissions from heavy air polluters. The benzene distribution does not follow this behavior, possibly due to the shortage of substantial stationary benzene emitters. Also, the considerable difference between the median and the mean of both xylene and toluene distributions suggests local emission impacts in Riyadh. O3 concentrations averaged 34.59 ± 24.17 ppb and were a maximum of 277.47 ppb, occasionally violating the 1-h national standard (120 ppb) and frequently exceeding World Health Organization (WHO) and United States Environmental Protection Agency (EPA) standards.

China has frequently suffered regional-scale haze pollution in recent years. In this study, real-time observation data such as PM2.5, PM10, SO2, NO2, CO and O3 were used to analyze wintertime haze events at a rural site (Dongshan) in the Yangtze River Delta (YRD). 3-hour resolution organic carbon (OC) and elemental carbon (EC) were also measured to further investigate the sources of PM2.5. The hybrid receptor models were used to identify source regions of PM2.5. The results showed that both regional transport and local emissions significantly contribute to air pollution at Dongshan during haze periods. The source areas affecting high PM2.5 concentrations were mainly located in nearby urbanized provinces (i.e., Jiangsu, Anhui and Zhejiang) and industrial provinces (i.e., Shandong and Hebei) in eastern China. Furthermore, open biomass-burning emissions in south China (i.e., Jiangxi, Hunan, Guangdong and Fujian) decreased regional air quality, which was supported by MODIS fire spots and receptor models. During clean periods, air masses were originated from remote regions such as Mongolia and oceanic areas (i.e., the Yellow Sea and the East Sea). Enhanced secondary organic carbon (SOC) formation was found under long-range transport when OC aging was favorable. Contrarily, relatively low SOC formation was found when the site was dominated by local emissions. In addition to local emissions, high PM2.5 concentrations at Dongshan were apparently affected by either regional or long-range transport, which were characterized by relatively low and high wind speeds, respectively. It is necessary to implement the emission control strategies for the industrial and urbanized areas.

We analyzed surface sediments from 23 northeast USA estuaries, from Maine to Delaware, and nine estuaries from Prince Edward Island (PEI, Canada), to determine how dinoflagellate cyst assemblages varied with nutrient loading. Overall the abundance of cysts of heterotrophic dinoflagellates correlates with modeled nitrogen loading, but there were also regional signals. On PEI cysts of Gymnodinium microreticulatum characterized estuaries with high nitrogen loading while the sediments of eutrophic Boston Harbor were characterized by high abundances of Spiniferites spp. In Delaware Bay and the Delaware Inland Bays Polysphaeridium zoharyi correlated with higher temperatures and nutrient loading. This is the first study to document the dinoflagellate cyst eutrophication signal at such a large geographic scale in estuaries, thus confirming their value as indicators of water quality change and anthropogenic impact.

Seasonal maritime traffic was investigated in relation to cetaceans, through direct observations (July 2013–June 2015) along three fixed transects in Western Mediterranean. Visually obtained vessel abundance was compared with Automatic Identification System data to explore if the two methods provided different results. Traffic intensity and composition were characterised by seasons and vessel categories. Finally, cetacean presence was investigated in relation to traffic by measuring the difference of vessel abundance in the presence and absence of animal sightings. Results showed that visual sampling was consistent with AIS data, providing more information on small-medium vessels. Traffic was more intense and diverse in Spring/Summer, and the highest vessel abundance and seasonal variations in composition emerged for inshore subareas. The difference of traffic in the presence and absence of cetaceans was higher in most offshore subareas in Spring/Summer, verified for B. physalus and S. coeruleoalba; in inshore waters, mostly occupied by T. truncatus, no significant differences emerged.