Aquatic wildlife is exposed through trophic transfer of hazardous substances to several threats inducing physiological impairments. We aimed at assessing the impact of contamination in one of the hot spots of pollution along Mediterranean coasts, the gulf of Gabes in Tunisia, on Common tern Sterna hirundo, a piscivorous top predator bird. Firstly, we compared the reproductive effort of breeding adults through clutch size distribution in three sites with different levels of pollution. Then, a battery of genotoxicity and oxidative stress biomarkers was carried out to assess physiological impairments in chicks. While defense mechanisms showed a depletion, lipid peroxidation and genotoxicity increased significantly according to pollution level. The multi-biomarker approach used here, discriminated chicks according to contamination degree of their nesting sites. Increases in genotoxicity and oxidative stress were correlated to a decrease in chick body mass known to lead to long-term impacts on juvenile survival and recruitment in birds.

The EYNR is the most important wetland in central Chile because it is protected as a RAMSAR site. It includes coastal lagoons, estuaries and saltmarshes, sustaining an important biodiversity. The chemical complexity was described using water and soil samples, which are characterized by high levels of alkalinity and soil cations. In addition, high concentrations of Cu (0.01–0.080 mg L⁻¹) and Pb (0.120–0.566 mg L⁻¹) in water were measured. Using a simplified index of water quality for oxygen demand, the ecological status of the wetland was classified as bad quality due to the existing use of land. Multivariable analyses and heavy metal index classified this wetland as having low to intermediate deterioration due to the combination of heavy metals. If this trend is allowed to continue unabated, the food web complexes in this wetland are likely to be at the highest risk of induced heavy metal contamination.

Microplastics are becoming a global concern due to their potential to accumulate pollutants in aquatic environments. In this paper, sulfamethazine (SMT) sorption onto six types of microplastics, including polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was investigated by experimental and molecular dynamics simulation methods. The experimental results indicated that SMX sorption reached equilibrium within 16 h. The kinetics of SMT sorption by PA, PVC, PE, and PP could be fitted by pseudo first-order model, while SMT sorption by PA and PET could be described by pseudo second-order model. The partition coefficient Kd values were 38.7, 23.5, 21.0, 22.6, 18.6 and 15.1 L·kg⁻¹ for PA, PE, PS, PET, PVC and PP, respectively. SMT sorption onto microplastics decreased when pH and salinity increased. The molecular dynamics simulation results indicated that the main mechanisms involved in sorption are electrostatic and Van der Waals interaction.

Dual isotope nitrate (NO₃⁻) analysis was performed on the western coast of Guangdong Province to investigate seasonal changes in the main nitrate sources and their biogeochemical processing, which are due to the rapid development of the local economy. In the nearshore area, significant seasonal variations of nitrate sources occurred. The dominant nitrate sources, originating from manure and sewage, suggested that the nitrate along the west coast of Guangdong Province was mainly influenced by local cities despite the westward flow of diluted Pearl River water. In the offshore area, the nitrate loss in the upper and mid water during both two seasons mainly caused by phytoplankton assimilation, whereas coupled nitrification-denitrification could be responsible for the nitrate loss in the bottom waters during summer. Our results suggest that, with the rapid development of local economy, the nitrate sources in the coastal area have shifted to manure and sewage from the local cities.

As microplastic pollution evolved to a well-established research field, microplastic scientists started to explore new avenues in the field. Yet, while a multitude of different types of microplastics (microbeads, fibres, fragments) have been well-documented in microplastic literature, our analysis of this literature shows that glitter particles have been overlooked by the field. However, due to the presence of glitter-based research in forensic science, we explore the idea that glitter may have the potential to act as “flag items” - or markers – of a likely source, due to the often complex and individual composition of glitter particles compared to traditional microplastics, such as microbeads. As such, this article demonstrates glitter has insofar been overlooked as a microplastic particle, and demonstrates that glitter may have an important role in explaining microplastic pollution dynamics from source to sink.

Despite the increasing interest in microplastic (MP) research, the accurate prevalence, distribution and fate of these materials in the environment is yet poorly known and, consequently, a focus of debate. Hence, to better ascertain the presence of microplastics in specific environments, samples from 35 random sites distributed across a 4200-meter long section from the area of Sidi Mansour, Sfax-Tunisia, were collected and analyzed. MPs were extracted, digested with potassium hydroxide and dyed with Eosin B, for visual microscopy counting and sorting. Polymer composition and surface morphology were identified by FTIR-ATR spectroscopy and SEM microscopy. Total abundances ranged from 252 to-5332 particles per m² where fragments and granules were the most frequent types of microplastics. These findings highlight the considerable presence of these materials in the studied harbor region and underscore the density dependence on the distribution and occurrence of MPs and how these tend to accumulate in the sandy sediments.

Since 2011, tropical beaches from Africa to Brazil, Central America, and the Caribbean have been inundated by tons of sargassum seaweed from a new equatorial source of pelagic sargassum in the Atlantic. In recent years the extraordinary accumulations of sargassum make this a nuisance algal bloom for tropical coasts. In 2018 satellite data indicated floating mats of sargassum that extended throughout the Caribbean to the northeast coast of Brazil with the highest percent coverage over the water yet recorded. A literature review suggests that Atlantic equatorial recirculation of seaweed mats combined with nutrients from several possible sources may be stimulating the growth and accumulations of sargassum. In the western equatorial recirculation area, new nutrient sources may include Amazon River floods and hurricanes; in the eastern equatorial recirculation area, nutrient sources that could sustain the sargassum blooms include coastal upwelling and Congo River freshwater and nutrients.

The Nerbioi-Ibaizabal estuary (Bilbao, Basque Country) suffered an important input of contaminants, including metals and metalloids, between 1875 and 1975. We collected sediments in the tidal part of the river in January 2018 and measured the concentrations of 27 elements in them. At that time, two important construction works were taking place in the area: the extension of the commercial port and the opening of long semi-closed channel. Comparing the current metallic hotspots with the geographical distribution of elements in previous years (2009, 2010 and 2014) showed us that these works seem to have significantly influenced the distribution of toxic elements in the estuary, even if the critical point of the second one is still to arrive with the inundation of the connection to the mainland. Long term pollution monitoring reveals as a powerful tool to check the effects of ongoing engineering works in estuarine environments.

Naturally occurring radioactive material was characterized in selected seafood samples from three areas in the Gulf of Mexico. Relatively desirable and abundant fish such as Red Snapper, Red Drum, Northern Whiting, and Spotted Trout as well as oysters were collected and analyzed using gamma spectroscopy to determine the concentration of ²²⁸Ra, ²²⁶Ra, and ⁴⁰ K. Average total activity concentration from these radionuclides were 0.9 ± 0.6, 1.6 ± 1.2, and 132 ± 57 Bq kg⁻¹ respectively, in the edible portion of wet weight samples. The results were consistent with previous studies for other bodies of water. A small but statistically significant increase in ²²⁶Ra was found in comparison to similar research performed 20 years prior. These measurements provide a reasonable baseline for the examined species from the Gulf of Mexico.

The bioturbation potential of macrobenthos communities (BPc) is an important parameter in marine ecology. Based on macrobenthos field surveys, BPc values were estimated in Bohai Bay, China. The horizontal distribution of BPc values changed across seasons while showing a certain level of continuity over time. The maximum BPc value was recorded in summer while the minimum occurred in winter. Although only a few environmental variables showed a statistically significant (p < 0.05) correlation with BPc, about 20 environmental variables exhibited a moderate correlation with BPc (0.3 < r < 0.5). The depth of the redox potential discontinuity (RPD) measured in situ changed across seasons, and the biogenic mixing depth values derived from the BPc index exhibited a relationship with the lowest RPD depth measurements. Our results suggest that the RPD depth can be predicted from BPc values, thereby showcasing a useful application of the BPc index in marine benthic pollution and environmental management research.