The main objectives of the present study were to measure the concentration of mercury in Alosa spp. muscle tissue and to assess the health risk to consumers. For this purpose, fish samples were collected from four regions of the southern coast of the Caspian Sea. Mean concentrations of mercury in the regions of Bandar Torkaman, Feridonkenar, Chalos and Bandar Anzali were 264.10, 73.74, 161.90, and 183.80 μg g−1 dw, respectively. The mercury averages obtained in all four regions were below the standards recommended by the World Health Organization (WHO), the Food and Agriculture Organization (FAO), the Standardization Administration of China (SAC) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The values of hazard quotient also showed no potential health risk for consumer. However, the assessment of other contaminants is recommended for more accurate conclusions about the health risks of consumers through the consumption of the fish.

The mechanism of fish kill events is not thoroughly understood in Kuwait Bay (KB). However, it is obvious that fish kill events have a close relationship with hypoxia due to some biogeochemical processes. Hydrodynamics controls the dissolved oxygen (DO) concentration that occurs within various spatial and temporal scales. The current study utilizes a previously validated hydrodynamic model to drive a three-dimensional water quality model for KB. The water quality model was validated using comprehensive field measurements during the summer of 2018. Reasonable model computations were achieved to represent the general patterns of the DO in KB. The model computations reproduced the formation of hypoxic water parcels. Some minor fish kill events that occurred during summer 2018 correlated well with predicted hypoxic parcels. The hydro-environmental controls over the extent of the hypoxic parcels and interplaying forces shall be addressed in a separate article by the same authors.

Vessels, specifically ballast water and hull fouling, are a major vector for the introduction of non-indigenous species (NIS) in European seas. The Mediterranean is one of the world's marine regions where their invasion is heaviest. The shallow Adriatic basin is a highly sensitive area that is already experiencing its consequences. The secondary spread of NIS over a wider area through natural dispersion is a complex process that depends on a wide range of oceanographic factors. This work analysed the dataset of the BALMAS project, in whose framework twelve ports in the Adriatic Sea were subjected to a Port Baseline Survey (PBS), to estimate the natural spread of NIS organisms from their port of arrival to the wider Adriatic basin. Its findings indicate that the prevailing water circulation patterns facilitate the natural dispersal of harmful aquatic organisms and pathogens (HAOP).

Sources of organic matter in a polluted coastal embayment (Lake Sihwa) indicated that δ¹³C and δ¹⁵N of suspended particulate matter (SPM) and sediments could be distinguished by land-use type and surrounding activities. Specifically, low δ¹⁵N occurred in inland creeks near industrial complex, where severe contamination by persistent toxic substances (PTSs) is evidenced. To identify the sources of ¹⁵N-depleted organic matter and PTSs, the SPM and/or sediments were collected along ~8 km of the Singil Creek and in stormwater drainage pipes that carried pollutants to the creeks from upland areas. Results indicated that stormwater originating in industrial areas was the main source of low δ¹⁵N and elevated PTSs, which appeared to flow into stormwater drains with rainwater and eventually into the creeks at stormwater outfalls. To improve the water quality of inland creeks, it will be necessary to reduce the amount of untreated stormwater entering stormwater drainage system from industrial complex.

A molecularly imprinted polymer (MIP) anchored on the surface of CdTe quantum dots (QDs) was fabricated and used as a fluorescent probe for sulfadiazine (SDZ) detection in seawater. CdTe QDs was used as photoluminescent material, SDZ as the template, 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethyl orthosilicate (TEOS) as the cross-linking agent. Characterizations of MIP-QDs were analyzed by Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM). The conditions were optimized for the detection of MIP-QDs to SDZ. The mechanism of fluorescence quenching was studied by UV–Vis absorption spectroscopy and fluorescence spectroscopy. Under optimal conditions, the fluorescence intensity of MIP-QDs decreased linearly between 4‐ and 20 μM SDZ with a good correlation coefficient of 0.995. The limit of detection is 0.67 μM and the recovery is between 91.8 and 109.4% with RSD lower than 3.9%. These results indicated that MIP-QDs for SDZ detection in seawater was developed successfully.

Djiboutian coral reefs are poorly studied, but are of critical importance to tourism and artisanal fishing in this small developing nation. In 2014 and 2016 we carried out the most comprehensive survey of Djiboutian reefs to date, and present data on their ecology, health and estimate their vulnerability to future coral bleaching and anthropogenic impacts. Reef type varied from complex reef formations exposed to wind and waves along the Gulf of Aden, to narrow fringing reefs adjacent to the deep sheltered waters of the Gulf of Tadjoura. Evidence suggests that in the past 35 years the reefs have not previously experienced severe coral bleaching or significant human impacts, with many reefs having healthy and diverse coral and fish populations. Mean coral cover was high (52%) and fish assemblages were dominated by fishery target species and herbivores. However, rising sea surface temperatures (SSTs) and rapid recent coastal development activities in Djibouti are likely future threats to these relatively untouched reefs.

North Abu Ali Island is contaminated by crude oil from exogenous sources with a variety of persistent toxic substances (PTSs) being input into intertidal sediments. We detected an array of PTSs in sediments and benthic biota off north Abu Ali Island (Arabian Gulf), including 35 polycyclic aromatic hydrocarbons (PAHs), 6 alkylphenols (APEOs), 10 styrene oligomers (SOs), and tributyltin. The PTS concentrations were generally greater than those reported in other areas of Arabian Gulf. PAHs mainly originated from petrogenic sources, and APEOs and SOs seem to be of recent origin. Field-based biota-sediment accumulation factors (BSAF) varied by taxa and compounds, but clearly depended on the log Kₒw values of individual compounds. Some PTSs exceeded the established guidelines for sediments and biota; we found particularly great BSAFs for alkyl-naphthalenes (C1- and C2-), nonylphenol monoethoxylates, and 2,4,6-triphenyl-1-hexene. Remediation will require on-site clean-up of toxic chemicals together with immediate efforts on preventing input of current pollution sources in the given area.

The chemical industrial zone located along the Xiaoqing River wetlands adjacent to Bohai Sea is one of the largest production bases for brominated flame retardants in China. Herein, high levels of bisphenol-A, tetrabromobisphenol-A (TBBPA), tribromobisphenol-A, dibromobisphenol-A, and monobromobisphenol-A were detected in sediment, soil, and water samples of this zone in the range of below method detection limit (<MDL)–5.45 × 10⁶ ng/kg dw, <MDL–8.37 × 10⁴ ng/kg dw, and <MDL–5.59 × 10² ng/L, respectively. They were mainly buried in sediments as their highest levels in sediment samples. The small concentration fluctuation between water samples retrieved in the upstream and downstream zones is likely attributed to seawater backflow. The nearby chemical factories were point pollution sources and the less brominated analogs are largely from debromination of TBBPA. High pollution levels and the ecological risks of these pollutants along the Xiaoqing estuary to Bohai Sea need to be further assessed in future studies.

We surveyed the deposition of drill cuttings on the seafloor along a transect at eight drilling locations in the south-western Barents Sea and Norwegian Sea, comparing traditional visual surveying methods and underwater hyperspectral imagery (UHI). The locations range from newly-drilled to around 30 years post-drilling. The visual assessments detected deposited drill cuttings to extend to around 150–200 m from the drilling location at recently drilled sites and generally less than 50 m at older locations. Quantitative UHI analyses of relative change in the spectral signature of the sediments with increasing distance from the drilling location mostly showed a change-over to conditions resembling undisturbed sediments at approximately similar distances as the visual assessments. Biological faunal community analyses also reflected these trends. The UHI-based detection of drill cuttings thus in general supported the results of visual assessments and potentially could be further developed as a method for automated surveying of drilling sites.

The present study investigates the occurrence of plastic pollution in two commercially important marine teleosts (Zeus faber and Lepidopus caudatus) from the northern coasts of Sicily (Tyrrhenian Sea). Plastics occurrence in the gastrointestinal tract was higher in Lepidopus caudatus (78.1%) than Zeus faber (51.4%). Debris characterization, carried out by micro-Raman spectroscopy, allowed identified the main types of found polymers as: polypropylene (PP), polyamide (PA), nylon and, to a lesser extent, polyethylene (PE). Of the two fish species studied, the silver scabbardfish appeared to be the more vulnerable to plastic ingestion. Our study represents a starting point that may pave the way for future investigation of the fate, accumulation and transfer of plastic debris to upper trophic levels, to verify their potential toxicity and to better understand strategies to mitigate this phenomenon.