The study presents a spatio-seasonal distribution of 13 trace elements in the surface water (0–5 cm) along the north–south gradient of Hooghly River Estuary, India, and subsequently evaluates the human health risk by adopting USEPA standards. An overall homogeneous spatial distribution of elements was pronounced, whereas an irregular and inconsistent seasonal pattern were recorded for the majority of the elements. The concentration range (μg/l) of the elements and their relative variability were obtained as follows in the decreasing order: Al (55,458–104,955) > Fe (35,676–78,427) > Mn (651.76–975.78) > V (85.15–147.70) > Si (16.0–153.88) > Zn (26.94–105.32) > Cr (21.61–106.02) > Ni (19.64–66.72) > Cu (34.70–65.80) > Pb (26.40–37.48) > Co (11.16–23.01) > As (0.10–8.20) > Cd (1.19–5.53). Although Pb, Ni, Cr, Al, Fe, and Mn exceeded the WHO prescribed threshold limit for drinking water, Metal Pollution Index values (8.02–11.86) superseded the upper threshold limit endorsing adverse impact on biota. The studied elements were justified to have a non-carcinogenic risk as derived from hazard quotient and hazard index values. However, the trace elements As, Cd, Pb, and Cr exceeded the upper limit of cancer risk (10⁻⁴), thereby leading to carcinogenic risk concern for both children and adult population groups, where children are more susceptible than the adults. Hence, evaluation of bioavailable fractions of the elements is required for proper management of this stressed fluvial system.

Environmental studies that use small Autonomous Underwater Vehicles (AUVs) can survey wider and deeper areas, compared to traditional methods, at a reasonable cost. Thanks to the precise vehicle navigation systems, the data collected can be accurately geolocalized. Besides, lightweight vehicles can be deployed from the shore or from small boats and programmed by means of user-friendly graphical interfaces, thus reducing and simplifying the need of human resources and infrastructures. Based on such a technology, this paper presents a framework to assess the environmental impact of a marine sewage outfall set in the Bay of Palma (Mallorca, Spain). We report the results of the analysis of the images recorded in the course of six missions conducted with an AUV. The plan was designed after a microbiological analysis detected the presence of cyanobacteria in a sample of sand and water collected by scuba divers close to the sewer pipe mouth.

This body of work demonstrated the levels of selected contaminants (as well as their potential sources), in mussels (Mytella guyanensis) - a known bio-indicator of pollution, along the west coast (Gulf-of-Paria) of Trinidad. The findings demonstrated that polyaromatic hydrocarbons levels in the mussels investigated were moderate to high (201.80–1200.08 μg/kg). Notably, benzo(a)pyrene levels (1.15–9.32 μg/kg) exceeded the European Union guidelines at various sites. The distribution of PAHs and trace elements in the Gulf of Paria are impacted by tidal currents and local source discharge. Significant risks were identified from toxic carcinogenic equivalent levels (3.01 to 22.37 μg/kg) and mutagenic equivalent levels (3.98 to 38.61 μg/kg). The concentration of trace elements, Zn (46.05–56.36 mg/kg) and Cd (0.46–1.17 mg/kg), exceeded both local and international guidelines at certain sites investigated. The analysis revealed a high bioavailability of the identified pollutants in the Gulf of Paria from industrial, urban and marine activities.

The aim of this study was to determine the activity concentrations and radiological hazard parameters of 137Cs and 40K in soft tissue samples of sea snails (Rapana venosa) collected from 12 different stations in the East Black Sea coastal area of Turkey. The values in soft tissues of sea snail samples with three different sizes were between 0.31 and 1.79 Bq kg−1 for 137Cs and 163.9 and 269.4 Bq kg−1 for 40K. The mean activity concentrations of 137Cs and 40K in tissues of small-sized sea snails were determined to be higher than those of 137Cs and 40K in soft tissues of the other sizes. The determined activity concentration values were lower than the concentrations reported in similar studies. Radiological hazard parameters such as the daily intake (Dint) of 137Cs and 40K, annual committed effective dose (Eeff), and lifetime cancer risk (LCR) were calculated and compared with the international recommended values.

Oil spills in the marine environment can have serious environmental, social and economic impacts. These impacts may be of transnational nature, and this makes the oil spill problem an international issue. Therefore, it is necessary to develop a common structured methodology for oil spill risk assessment. In this research, a general framework is presented for probabilistic risk assessment of oil spill from offshore oil wells. A case study is also performed in Persian Gulf to quantify the risk posed by 357 offshore wells to the near-shore receptors. First, thousands of hypothetical spill scenarios of different volumes are defined and simulated using a Lagrangian particle tracking model. Then, the result of the simulations is statistically processed to generate the risk networks and risk maps. The result of this research shed light on the importance of the pattern of environmental forcing elements and the frequency of spills in oil spill risk assessment.

The determination and evaluation of nickel and chromium in Tuzla Aydinli Bay is an important subject since it is an industrial marine area for decades and it is crucial to protect aquatic life which are toxic for the aqueous environment. In this study, 32 samples were collected both from near the coastal shipyard activity to far of the activity areas in Tuzla Aydinli Bay, Istanbul (Turkey) according to the standard guidance. Nickel and chromium were determined in the sea water and sediment samples by graphite furnace atomic absorption spectrometry. The contamination factors and geoaccumulation indices with respect to nickel and chromium were calculated and evaluated. Based on the modified ecological risk assessments, variable results were obtained depending on the selection of control (blank) points.

This study investigates the extra UV fluence needed to meet the International Maritime Organisation's ballast water discharge standards for the 10–50 μm size-class using the approved vital stain (VS) method compared to the Most Probable Number (MPN) method for organism viability assessment. Low- and medium pressure UV collimated beam treatments were applied to natural algae collected in temperate and tropical water environments and analysed using both methods. About 10 times higher UV fluence was required to meet discharge standards when using VS compared to MPN. Implementing a dark-hold period after UV treatments decreased algal viability. Length of dark-hold period to meet discharge standards decreased with increasing UV fluence. No significant differences between temperate and tropical samples were observed. The results showed that UV treated algae assessed using the VS method could meet discharge standards by increasing fluence and/or introducing a dark-hold period.

Little is known about the dynamics of particulate inorganic and organic matter in brackish water controlled by tidal prism and seasonal river discharges in Macuse estuary, on central Mozambique coast, southern Africa. This manuscript illustrates seasonal variation of biogeochemical flow dynamics in a tropical estuarine system in Zambézia province. The data were collected at 42 stations, including tidal current measurements with an Acoustic Doppler Current Profiler, tidal elevation with a tidal-gauge and nitrate, silicate (SiO2), dissolved oxygen and chlorophyll-a with a photometer device system and tidal currents with multisensory instrument device (Current, Temperature and Depth device). These field data helped to calibrate a twelve months simulation of a 3D Computational Aquatic Ecosystem Dynamics Model (3D CAEDM) in 2014. The results emphasize a tidal elevation of 4-m height that generated tidal currents of 120 cm/s. They combination with seasonal runoff of ~500 m3/s from Namacurra River and averaged bathymetry morphology of 10-m depth, led on to the seasonal concentration flux of dissolved oxygen, nitrate, SiO2 and chlorophyll-a during the ebbing and flooding. In addition, the river discharges were found to be the main source of nitrate and SiO2, while the tidal prism led on the hydrological flow of the brackish-waters during the rainy season with maximum salinity anomaly of 16%. Besides the data obtained, the 3D model matches in reproducing the biogeochemical data flow have considerable potential possess of a valuable information in long- and short-term and large- and small-scale that may allow policy-makers to determine political decisions for bio-conservation, sustainability and coastal management.

Storm-driven transport of MC252 oil, sand and shell aggregates was studied on a low-relief coastal headland beach in Louisiana, USA including measurement of alkylated PAHs and Illumina sequencing of intra-aggregate microbial populations. Weathering ratios, constructed from alkylated PAH data, were used to assess loss of 3-ring phenanthrenes and dibenzothiophenes relative to 4-ring chrysenes. Specific aggregate types showed relatively little weathering of 3-ring PAHs referenced to oil sampled near the Macondo wellhead with the exception of certain SRBs sampled from the supratidal environment and samples from deposition areas north of beach. Aggregates mobilized by these storm-driven washover events contains diverse microbial populations dominated by the class Gammaproteobacteria including PAH-degrading genera such as Halomonas, Marinobacter and Idiomarina. Geochemical assessment of porewater in deposition areas, weathering observations, and microbial data suggest that storm remobilization can contribute to susceptibility of PAHs to biodegradation by moving oil to beach microenvironments with more favorable characteristics. (149).

After the Fukushima nuclear accident (FNA), ¹³⁷Cs activities of seawater in the Western North Pacific (WNP) and China Seas were determined in order to examine whether ¹³⁷Cs derived from FNA across the Kuroshio was still existed and if there were any indications of FNA's impact. High ¹³⁷Cs activities at 200–500m were observed in the south of Kuroshio during 2015, indicating ¹³⁷Cs from FNA could cross the Kuroshio. Surface ¹³⁷Cs activities were on average 1.43±0.42Bqm⁻³ for WNP, 1.11±0.14Bqm⁻³ for South China Sea (SCS) and 1.10±0.29Bqm⁻³ for East China Sea (ECS) during 2011–2015. The activities and inventories of ¹³⁷Cs were almost identical before and after the FNA, indicating the impacts of FNA on the WNP and China Seas were minor. The effective environmental half-lives of ¹³⁷Cs in surface seawater were firstly estimated to be 14.4±1.7yrs for ECS and 16.9±2.1yrs for SCS.