Owing to the environmental sensitivity of ciliate species, the monitoring and assessment of these communities can indicate the health of the aquatic environment. Sampling for loricate ciliates was carried out during different seasons at three different locations in the estuarine and coastal waters of Kochi, Southwest coast of India. The loricate ciliate community comprising of 27 species belonging to 10 genera revealed significant differences among the three sampling locations. The maximum numerical abundance and less species diversity of loricate ciliates were recorded at the estuarine locations whereas the minimum abundance and more species diversity were encountered in the coastal waters. Multivariate statistical analyses revealed that Tintinnopsis beroidea and Tintinnopsis uruguayensis were correlated positively with nutrients in the estuarine environment, which receives large amount of anthropogenic inputs. Thus, we propose that these two loricate ciliates may be considered as a potential bioindicator of eutrophication status in marine ecosystems.

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.

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.

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.

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.

Eighty-three surface sediments were collected to investigate the element concentration based sediment pollution and potential ecological risk status of the Pulicat lagoon, southeast coast of India. The textural characteristics, Fe and Mn concentration in the surface sediments are chiefly controlled by the confluence of riverine inputs and vicinity of the marine environment. The varied distribution of CaCO₃ concentration is due to the depth of the lagoon followed by the sand and silty sand characteristics of the substratum. The surface sediments are derived from riverine sources. Sediment Pollution Index (SPI), Potential Ecological Risk Index of the sediments suggests that they are falling under less polluted and low potential ecological risk category.

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.

Concentrations of selected antibiotic compounds from different groups were measured in sediment samples (14 analytes) and in near-bottom water samples (12 analytes) collected in 2011–2013 from the southern Baltic Sea (Polish coastal zone). Antibiotics were determined at concentration levels of a few to hundreds of ng g−1 d.w. in sediments and ng L−1 in near-bottom waters. The most frequently detected compounds were sulfamethoxazole, trimethoprim, oxytetracycline in sediments and sulfamethoxazole and trimethoprim in near-bottom waters. The occurrence of the identified antibiotics was characterized by spatial and temporal variability. A statistically important correlation was observed between sediment organic matter content and the concentrations of sulfachloropyridazine and oxytetracycline. Risk assessment analyses revealed a potential high risk of sulfamethoxazole contamination in near-bottom waters and of contamination by sulfamethoxazole, trimethoprim and tetracyclines in sediments. Both chemical and risk assessment analyses show that the coastal area of the southern Baltic Sea is highly exposed to antibiotic residues.

There is a substantial need for tools that effectively predict spatial and temporal fecal pollution patterns in estuarine waters. In this study, statistical models of exceedances of shellfish fecal coliform (FC) water quality criteria were developed using a 10-year dataset of FC levels and environmental data. Performance (sensitivity, specificity, and predictive capacity) of five different types of models was tested (MLR regression, Tobit (censored) regression, Firth's binary logistic regression (BLR), classification trees, and mixed-effects regression) for each of three conditionally managed shellfish-harvesting areas in Tillamook Bay, Oregon (USA). The most influential variables were related to precipitation and river stage height in the wet season and wind and tidal-stage in the dry season. Classification tree and Firth's BLR approaches better explained exceedances of shellfish water quality standards than the current closure thresholds. Findings demonstrate the utility of statistical modeling approaches for improved management of shellfish harvesting waters.

Inorganic arsenic (As) is one of the most toxic pollutants in the water. We have studied their effects on the marine teleost European sea bass (Dicentrarchus labrax) at 2 and 10 days of 5 μM of As2O3 (sub-lethal doses) waterborne exposure. Arsenic accumulates in liver and gill tissues. The expression profile of five genes (bax, blc2, casp3, casp8 and casp9) involved in apoptosis cell death confirmed apoptotic effects in liver, slight changes in gill and no effects in skin according with the histopathology findings. Total IgM level and peroxidase activities were increased at 2 and 10 days, respectively. The bactericidal activity was decreased at 2 days after As exposure. A general decrease of cellular immune activities with significant differences in the case of respiratory burst activity was observed after 2 and 10 days of exposure. This work describes for the first time the effects of As exposure on European sea bass.