On March 2020, hydroxychloroquine (HCQ) was recommended as a treatment for COVID-19 high risk patients. Following the massive and widespread use of HCQ worldwide, a discernible high quantity is anticipated to end-up through the sewage systems in marine coastal areas. A closed microcosm study was undertaken herein for 30 days where meiobenthic nematodes were exposed to a range of HCQ concentrations (3.162, 31.62 and 63.24 μg.ml⁻¹). After one month of exposure in HCQ, the total abundances and Shannon-Wiener index of the assemblages decreased, whereas the individual mass and the Trophic Diversity Index increased at the highest concentrations. Overall, a numerical negative impact was observed for the epistrate feeders and non-selective deposit feeders, however, this benefited to the omnivores-carnivores, and particularly to the Oncholaimids. Such responses of the nematodes 2B and the corresponding taxa are bioindicative of current- or post-COVID-19 crisis risks in relation with the bioaccumulation of HCQ in seafood.

Thirty cores to maximum depth of 3.7 m were taken in 2018 to investigate sedimentary characteristics and hydrocarbon penetration within mangrove sediments in Bodo (southeastern Niger Delta), an area contaminated by numerous ongoing oil spills but most significantly in 2008. Sediments were dominated by organically rich (Chikoko) mud underlain by clay with sandier sediments at deeper core depths and adjacent to shorelines. Analysis of 202 samples showed high median hydrocarbon concentrations at the surface (39,000 mg/kg) and shallow subsurface (10–25 cm, 25,000 mg/kg), decreasing with depth: 430 mg/kg at 40–70 cm; 157 mg/kg at 75–120 cm, and <30 mg/kg at depths ≥150 cm. Most (85%) EPA-16 priority polycyclic aromatic hydrocarbons and all monoaromatics were below detection limit. Shallow subsurface oil penetration was aided by crab burrows and presence of mangrove remnants and was inhibited from deeper depths by groundwater at ~25 cm and increased sediment compaction.

Microplastics (MPs, 0.2-5 mm) contamination of water outside/inside thickets of macrophytes in the Baltic Sea was studied. The amount of MPs particles in water samples taken within thickets is on average 1.7 times higher than in water samples taken in the areas outside thickets. Fibres are the predominant type of MPs (92.5%). For algae growing on boulders, the abundance of MPs is 1245 ± 1020 items/m². Per kilogram of dry algae mass the MPs abundance is 376 ± 404 items/kgDW for all shapes of MPs particles. This value is one order of magnitude higher than in sands of the swash zone in the given area. It is shown that filamentous algae retain more fibres than cartilaginous ones: 1.9-8.5 versus 1-1.1 items/l on average. Obviously, areas covered by sea grasses are much more contaminated than water and sediments in the given region.

European legislation requires monitoring of toxic algae in marine areas where shellfish are harvested for consumption. Monitoring assumes the existence of homogeneous water bodies, the definition of which have important implications for stakeholders and consumers. Yet, the definition of homogeneous water bodies remains unclear. Here we present a methodology to divide coastal and estuarine waters into homogeneous water bodies to monitor toxic algae. The proposed method is mainly based on water transport, and secondarily on oceanographic characteristics; salinity and sea surface height. We apply the methodology to the Limfjord in Denmark and demonstrate its usefulness in areas with a complicated coastal morphology. The oceanographic descriptors applied in the method are standard outputs from coastal hydrodynamical models. Provided that validated and high resolution model output is available for a given area, the technique is thus adaptable to other morphologically and oceanographically complicated estuarine and coastal areas where toxic algae monitoring is necessary.

The increasing amount of marine litter is a global issue that is also being experienced within the Manila Bay Philippines. To better understand the behavior of litter within the bay, particle tracking simulations of floating litter released from several sources were conducted. Forward-in-time (PTM-FIT) simulation of particle movements showed that during the southwest monsoon season, litter particles released by river sources tend to accumulate toward five hotspots located along the northeastern coastline of the bay. Backward-in-time (PTM-BIT) simulation of particles released from the identified hotspots showed coastal and foreign sources contributing to the litter collected within these areas. PTM-FIT simulations during the southwest monsoon season showed that particles tend to circulate locally within the bay before being transported toward the hotspots. By contrast, PTM-FIT simulations during the northwest monsoon season showed that litter particles tend to travel toward the mouth of the bay, an implication for global marine litter pollution.

The North-West coast of India was notable for the urbanization and semiarid climate, particularly the Gujarat coastal region which was facing water crises and aquifer salinization issue. Under the light of these critical issues, the present study investigates the sources of aquifer salinization and probable location of submarine groundwater discharge (SGD) using an integrated approach of major ion chemistry, statistical techniques, and isotopic signature of groundwater (GW). The evolution of GW reveals that water facies changes from Ca²⁺-Mg²⁺-Cl⁻ to Na⁺-Cl type from the south Gujarat towards the Gulf of Khambhat. Log-normal distribution of Cl⁻ and NO₃⁻ divulges that different pollution sources influence the GW quality. Statistical findings supplemented with Isotopic signatures, ionic ratios and cross plots identified four classes of GW, which varies with degree of anthropogenic and seawater influences. Results suggested that seawater intrusion heavily influences 42% of the total GW samples, whereas 58% samples showed the probability of SGD. The study recommends the feasible locations of check dams as a remedial measure for controlling the salinization of coastal aquifer.

We report seasonal and temporal variation of total organic carbon (TOC) in the eastern Arabian Sea (AS). In comparison to the deep, TOC in the top 100 m showed spatial variation with higher concentrations towards northern AS during North east monsoon (NEM) and South west monsoon (SWM). A comparison with the US-JGOFS data (1995) shows warmer temperatures, enhanced TOC and low chlorophyll in the recent years. High TOC is associated with Arabian Sea high saline waters (ASHSW), advected from the Arabian Gulf, might have resulted in an enhancement of TOC in the eastern AS. This excess TOC supports a high abundance of bacteria despite the low primary productivity. TOC oxidation accounted for 14.3% and 22.5% of oxygen consumption for waters with potential density between 24.5 and 27.3 kg/m³. This study attains great significance considering the missing links with respect to the role of transport processes in ocean deoxygenation under ongoing warming scenarios.

Marine litter, such as plastic bags, bottles, fabrics, or fishing gear, serve as a shelter for many marine organisms that are likely to colonize artificial substrata. Such assemblages can potentially turn marine litter into vectors of alien invasive species (AIS). Here, we report the abundance and diversity of macroinvertebrates inhabiting marine litter in Peruvian beaches. Results indicate that most of the fouled items found came from land-based sources (81.5%) and Bivalvia was the most abundant class (53.5%), mainly composed of the mussel Semimytilus algosus. No significant differences were found in the abundance and diversity of macroinvertebrates (class level) among sampling sites or sources of litter. Polypropylene and low-density polyethylene items were most frequently found with fouled biota. Although none of the identified species were non-native to the coast of Peru, we discuss marine litter as a potential source of AIS in this region.

In this work data of salinity, temperature, suspended particulate matter (SPM), chlorophyll-a, and phytoplankton concentration in the Gibraltar Strait coast, in the confluence of the Mediterranean Sean and the Atlantic Ocean, were analyzed together with ²¹⁰Po, ⁴⁰K, ²¹⁰Pb and ²³⁴Th activity concentration in different types of bivalve molluscs at the same time-period. The physicochemical parameters were evaluated using the Copernicus Marine Environment Monitoring Service (CMEMS) products based on satellite observations. A multivariate statistical analysis, including contrasted natural radioactivity contents, allowed the discrimination of bivalve molluscs from Atlantic and Mediterranean coasts. Additionally, a cluster analysis determined a highly significant negative correlation ²¹⁰Po concentration in molluscs and phytoplankton concentration suggesting that phytoplankton concentration in the water column is a determinant factor to regulate ²¹⁰Po concentration in those animals. These results introduce a useful tool to calculate the radiological doses in seafood from chlorophyll satellite image.

PURPOSE OF REVIEW: Triclosan (TCS) is a broad-spectrum antimicrobial agent that has been widely used in pharmaceutical and personal care products. TCS enters the environment mainly in effluent and biosolids from wastewater treatment plants, and persists in the aquatic environment and edatope. TCS is potentially harmful to the environment and biohealth because of its properties, being lipophilic, accumulative, toxic, and persistent. Therefore, TCS has become a research hotspot in recent years. The purpose of this review is to summarize the occurrence, toxicity, ecological effects, and removal methods of TCS. RECENT FINDINGS: TCS has a long half-life, and is found widely in the environment. Toxicity and ecological effects of TCS have been found in recent studies. Moreover, TCS has joint effects with multiple pollutants, and many of its transformation products are also toxic. Methods to remove TCS from the environment include adsorption, advanced oxidation technology, ecological engineering, and applying multiple methods in tandem. Each method is constantly being updated. This paper reviews recent research done on TCS, focusing on its occurrence, toxicity, ecological effects, and removal. Finally, several perspectives for research on this substance are outlined.