The aim of this study was to appraise the response of a multi-marker approach in fish species, Gobius niger and Zosterisessor ophiocephalus, in a polluted lagoon (Bizerte lagoon: MB and ML sites) and in a reference site (Ghar-El-Melh lagoon entrance) by the analysis of physiological indexes, liver histopathology and some biochemical biomarkers. The results showed liver hypertrophy in fish collected from Bizerte lagoon as well as many non-specific lesions, unlike the reference site. All Bizerte lagoon sites had the same prevalence of histopathological lesions, but the mean intensity (MI) of parasites seemed to be more sensible as an indicator of pollution levels. Indeed, parasite MI was more important in MB site that has a higher pollution level. Also, biochemical biomarkers showed an induction in Bizerte lagoon sites with some differences within sites and species. The impact of the continuous release of pollution on the biomarker's response is discussed.

In this study we report the concentration levels of heavy metals (including Pb, Cd, Hg, Cr, Ni, Fe, Mn, Cu) in ballast water of commercial ships, entering Bushehr port for the first time in the region of the Persian Gulf. The concentration levels of Cu and Fe in all samples of the ballast water were higher compared with the coastal waters of Bushehr port. In the case of Cd, 76.47% of samples had higher concentration level compared with the coastal waters of Bushehr port. Results showed that in a long term the ballast water has the potential to change the chemical quality in marine environments and also may affect the human health and marine ecosystem where ships discharge their ballast water. Therefore, permanent monitoring as well as treatment of ballast water before discharging is crucial to keep the marine environment health.

After Deepwater Horizon oil reached the Florida coast, oil was buried in Pensacola Beach (PB) sands to ~70cm depth, resulting in Total Petroleum Hydrocarbon (TPH) concentrations up to ~2kg per meter of beach. This study followed the decomposition of the buried oil and the factors influencing its degradation. The abundance of bacteria in oiled sand increased by 2 orders of magnitude within one week after oil burial, while diversity decreased by ~50%. Half-lives of aliphatic and aromatic hydrocarbons reached 25 and 22days, respectively. Aerobic microbial oil decomposition, promoted by tidal pumping, and human cleaning activities effectively removed oil from the beach. After one year, concentrations of GC-amenable hydrocarbons at PB were similar to those in the uncontaminated reference beach at St. George Island/FL, and microbial populations that disappeared after the oil contamination had reestablished. Yet, oxihydrocarbons can be found at PB to the present day.

Hurricanes can cause widespread environmental pollution that has yet to be fully articulated. This study develops a predictive water quality model to forecast potential contamination resulting from buckled or ruptured storage tanks in coastal industrialized areas when subjected to storm surge. The developed EFDC-Storm Surge model (EFDC-SS) couples EPA's EFDC code with the SWAN-ADCIRC hurricane simulation model. EFDC-SS is demonstrated using the Houston Ship Channel in Texas as a testbed and hurricane Ike as a model hurricane. Conservative and decaying dye runs evaluated various hurricane scenarios, combined with spills released at different locations and release times. Results showed that tank locations with shorter distances to the main waterbody and lower ground elevations have a higher risk of inundation and rapid spill mass transport. It was also determined that hurricane strength and landfall location, the location of the spill, and the spill release time relative to peak surge were interdependent.

The Jiulong River watershed (JRW) in southeast China includes livestock breeding and agriculture, leading to large amounts of non-point source pollution. Nitrogen (N) reductions were simulated and mapped using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) under scenarios that were built considered both constructed wetlands (CWs) and climate change, which are not common in the literature on ecosystem services assessments. The results showed that the amount of N exported from non-point sources within the JRW was 12,569 t·yr⁻¹. The areal N load was relatively higher in the north, while more N exported in the southeast. Constructed riparian wetlands can intercept and reduce the N loads that enter water bodies, but climate change may be a factor driving the deterioration of water quality. The methodology can be generalized to reduce other contaminants, and provides a tool for decision-makers to weigh the costs and benefits of urbanization and conservation.

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.