Titanium (Ti) is considered a contaminant of emerging interest, as it displays toxic potential and has been increasingly employed in everyday products, pharmaceuticals, and food additives, mainly in nanoparticle form. However, several knowledge gaps are still noted, especially concerning its dynamics in the water. In this context, this study aimed to quantify total Ti concentrations in highly consumed swimming crabs, squid, and shrimp from an important estuary located in southeastern Brazil. Ti concentrations were higher than those reported in most studies carried out worldwide. Animal length and weight, as well as, depth, transparency, dissolved oxygen, and salinity, significantly influence Ti concentrations in the animals. Human health risks were also noted after calculating a simulated exposure to titanium dioxide, especially considering the uncertainties regarding the effects of this element and the absence of regulatory limits.

Pinnipeds are sentinel species for marine pollution, but their role as vectors of trace elements (TEs) or rare earth elements (REEs) to ecosystems has been poorly studied. The present study tested pinniped feces for 61 elements, including REEs. Feces of adult seals (Mirounga leonina, Hydrurga leptonyx) from Fildes Bay, King George Island, Antarctica, were analyzed by ICP-MS. TEs varied by several orders of magnitude across the suite examined herein, with Fe, Al, Zn, Mn, HgII and Sr as the top six in both species. Of the REEs, Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Y and Yb were found consistently in all samples and ranged from 0.935 to 0.006 μg g⁻¹ d.w. The results show that both species act as biovector organisms of TEs and REEs through feces in remote environments, whose actual impacts and long-term fate need further exploration.

Distribution and ecological risk assessment of trace metals were carried out in the core sediments of a highly urbanized tropical mangrove ecosystem along the Southwest coast of India. The metal distribution pattern was as follows: Co, Cu, Ni and Pb adsorbed onto Fe oxyhydroxides and fine grained sediments; Cd and Zn preferential adsorption by organic matter and Cr scavenging by Mn oxyhydroxides. Cd, Pb and Zn were significantly enriched in upper sediments, while Cd, Ni and Zn were present in metal exchangeable fractions. Geoaccumulation index (Igₑₒ) suggested that the study area showed moderate to strong pollution of Cd and Zn, whereas unpolluted to moderately polluted with respect to Co, Cr, Cu, Mn, Ni and Pb. Cd enrichment caused high ecological risk, primarily attributed to anthropogenic activities. Mangrove ecosystems are efficient sequester of trace metals but anthropogenic addition can cause significant fraction of exchangeable metals and pose high ecological risk.

Concentrations of total mercury, total selenium, and cadmium ([THg], [TSe], [Cd]) were determined in hair of California sea lion (Zalophus californianus) pups from four islands of the Gulf of California and the Baja California Pacific coast (NG, CG, NP, and CP) to identify geographical differences and the effect of Se against Hg toxicity (TSe:THg molar ratio). THg displayed a strong north-south trend for both ecoregions, while TSe presented a significantly high concentration only for CG. TSe:THg molar ratios decreased when [THg] increased, with the lowest ratios presenting in NG pups, in which [THg] exceeded toxicological thresholds of concern. [Cd] presented similar values at all study sites except CG, which presented the lowest level. The present study shows that proximity to urbanized coastal areas has a strong influence on [THg] in pups, while [TSe] and [Cd] are probably more related to the physiological requirements of the species, and environmental conditions.

Oysters and clams are abundant and popularly consumed seafood in Viet Nam. These bivalves were proved to be suitable bioindicators to assess the heavy metal accumulation in the aquatic environment. The study is to investigate heavy metals such as As, Cd, Hg and Pb in the cultured oysters Saccostrea glomerata and clams Meretrix lyrata collected in VanDon - Quang Ninh, and CatBa - Hai Phong. The results showed that the metal heavy concentrations in the oysters Saccostrea glomerata and clams Meretrix lyrata presented in the order of As > Cd > Pb > Hg. The most polluted concentration with As among four heavy metals studied in six sampling sites was 2.81 ± 1.07 and 1.6 ± 0.62 mg/kg wet weight for clams and oysters, respectively. Investigated heavy metals in cultured oysters and clams indicated potential risks for human health in future by assessment of the heavy metals.

Based on survey data from the Bohai Sea of China in autumn (October) and winter (December) 2019, the structural characteristics of phytoplankton communities and their relationship with environmental factors were analysed. A total of 114 species of phytoplankton belonging to 84 genera and 3 phyla were identified. Warm-water species occurred frequently but cold-water species decreased in the Bohai Sea. This was associated with global warming and rising water temperatures. By comparing with historical data, Paralia sulcata gradually flourished and became the dominant species in autumn and winter, whereas the dominance of Skeletonema costatum decreased. The marine environment of the Bohai Sea has improved significantly in recent years, and phytoplankton biodiversity has increased. In autumn, both total phytoplankton and dinoflagellates were negatively correlated with salinity, and Pseudo-nitzschia delicatissima was positively correlated with nitrite and ammonia nitrogen. In winter, Nitzschia spp. showed a positive correlation with nitrate and a negative correlation with salinity.

The seasonal pattern of microplastics (MPs) contamination of the French littoral area of the Pertuis Charentais, one of the main French shellfish production regions, was assessed for the first time, between May 2019 and May 2020 at four different sites. The reference site was located at “Ile de Ré” and the other sites were located in the estuaries of the Sèvre Niortaise, Charente and Seudre rivers. Both blue mussels (Mytilus edulis) and Pacific oysters (Magallana gigas), that are considered sentinel species for the quality of the marine environment were analysed, along with sediment and seawater samples. MPs were extracted from each sample, counted, measured and sorted by colour and type. Micro-Raman spectroscopy was used to determine the proportion of confirmed MPs and the polymer types. The results showed that the contamination of mussels by fibres and fragments (1.9 ± 2.1 MPs/g ww) was significantly higher than for oysters (0.4 ± 0.4 MPs/g ww). Specifically, the contamination by fibres in both species was significantly greater than the contamination by fragments. Significant variations of MPs contamination were observed across the seasons and sites in bivalves, and depended on the species and the type of MPs (fibres or fragments). Mean concentrations of MPs measured in water and sediment were 0.007 MPs/L and 210 MPs/kg dw, respectively. Finally, blue was the dominant colour for fibres (79 %) and fragments (81 %). Blue fragments were mainly made of PS (70 %) followed by PC (18 %) and PP, PA or PLA (3 %) whereas blue fibres were mainly made of PA (80 %) followed by PET (13 %) or PP (7 %). This rare environmental case study of long-term chronic exposure of farming areas to MPs provides new knowledge on in situ variations of plastic fibres and fragments contamination throughout the seasons.

Plastic pollution in the ocean primarily originates from the land-derived mismanaged plastic waste that is transported by rivers. This study aimed to estimate the plastic litter generation in the surface water in Jakarta and Indonesia. A field survey was conducted at six riverine sampling points (upstream to downstream) and three holding facilities of the litter in Jakarta during the rainy season. The Jakarta Open Data database was used to estimate the tonnage of plastic litter. By mass, plastic comprised approximately 74 % of the anthropogenic litter in rivers and 87 % in holding facilities. The riverine plastic proportion slightly increased downstream. Approximately 9.9 g/person/day of plastic litter was discharged into Jakarta's surface water during rainy season and recovered by floating booms. To reduce plastic pollution and its severe impacts on aquatic ecosystems and human health, further field investigation is necessary to design an effective clean-up system and litter-prevention strategy.

To evaluate the prospects of using Baikal endemic sponges as bioindicators of chemical elements pollution, the elemental composition of sponges, water and substrate samples, collected in two areas with different levels of anthropogenic loading of the Baikal Lake, was determined using two analytical techniques. The content of Cl, Ca, V, Zn, As, Se, Ba, Cd, and Cu in the sponges collected in Listvennichny Bay was significantly higher than in Bolshye Koty Bay. The values of the pollution indices point at the slight to moderate pollution of the substrates. According to the bioaccumulation factor values, sponges accumulate mainly Cd, Cu and Br from the substrate, and the main part of the elements from water. The distribution of elements longwise the sponges and their intraspecific variation were evaluated. It was shown that Lubomirskia baikalensis sponges were suitable bioindicators to assess the pollution of Lake Baikal.

The spatio-seasonal variation, bioaccumulation and potential ecological risk of four metals (Co, Ni, Cu and Zn) in the multi-media of the Pearl River Estuary (PRE) were assessed. The degree of contamination and ecological risk of the four metals followed this pattern: Cu > Zn > Ni > Co, upstream > downstream, wet season > dry season. There were non-linear and linear correlations for Co, linear and non-linear correlations for Ni, and non-linear and no correlation for both Cu and Zn, between metals in bottom water or bioavailable concentrations in sediment and fish muscle. Co and Ni showed lightly polluted levels; Cu and Zn showed heavily polluted levels. This study demonstrates a tendency of cross-accumulation in fish of these four transition metals within specific habitats of the PRE.