Organic pollutants are ubiquitous in estuarine areas, nonetheless, the transport mechanisms of herbicides in such areas are limited. Atrazine and acetochlor were analyzed in suspended particle matter (SPM), surface sediment, and surface water from the Yellow River estuary and the surrounding rivers and sea. Among these rivers, the Yellow River contributes the most herbicide flux to the sea annually. The herbicide concentrations in water and sediment decreased from the estuarine areas to the deep sea. The fugacity fraction values of atrazine exceeded 0.5 in the Yellow River estuary, which supported that the herbicides in sediment desorbed at the estuarine areas. The herbicide in the SPM showed high concentration in the outer sea and increased as a power function with decreasing SPM content. The increasing partition capacity indicated that the herbicides tended to sink into sediment, increasing the ecological risk posed by herbicides. The ecological risk of acetochlor deserves continuous attention.

Collected sediment samples from the cage fish farm were measured to determine carbon and nitrogen stable isotope compositions and to understand the influence of the aquaculture waste on the sediment. The average δ¹³C of the sediment organic matter was −27.2 ‰ and −26.5 ‰, and the average δ¹⁵N value was 5.6 ‰ and 6.2 ‰ in October 2017 and November 2018, respectively. A linear mixing model was used to calculate the contribution ratios of the aquaculture waste in sediment organic matter. The contribution ratio of fish feces was 53.9 % and 25.5 %, and the contribution ratio of waste feed was 18.4 % and 52.6 % in October 2017 and November 2018, respectively. The sediment in the “cage fish area” was characterized by high waste feed ratio in sediment organic matter. The sediment organic matter was affected by the aquaculture waste even at sites 1500 m away from the cage fish farm.

In recent years, the microplastics (MPs) pollution in the offshore of microplastics has gradually become a concerning topic, and the understanding the accumulation of MPs in different tissues of organisms is also an important aspect. MPs can easily affect target tissues and transport related chemicals to humans through the food chain. MPs in the gills and guts of fish in the artificial reef area of Haizhou Bay and adjacent waters were detected in this study. The results showed that MPs were ubiquitous in the gills and guts of 26 species, with average quantities of 3.54 ± 2.14 pieces/fish and 3.00 ± 2.63 pieces/fish, respectively. More than 99% of the plastics were MPs that were less than 5 mm in diameter, with blue fiber being the most common. The number and quantity of MPs in gills were higher than those in guts in different habitat types, living water layers and feeding habits of fish. At the community level, as the body length and body weight increased, the quantity of MPs in the gills and guts showed a slight decreasing trend, and the correlation was not strong (P > 0.05). With increasing trophic levels (TLs), MPs were biomagnified in the guts (Trophic magnification factor, TMF = 1.37), but no change occurred in the gills (TMF = 1.00). We believe that biomagnification of MPs should be obtained by comparing the quantity of MPs in whole organisms rather than only in specific tissues before such conclusions can be defined. We recommend that periodic marine monitoring programs be implemented, as well as research into smaller MPs and even nanoplastics, to assess from the perspective of water, sediments, organisms and ecotoxicology, which will provide useful information for MPs pollution in artificial reefs and help to improve the MPs pollution database in China.

Rare earth elements (REEs) are increasingly used in various industries worldwide, resulting in their release into aquatic ecosystems. We evaluated the distribution and bioaccumulation of 14 REEs in marine sediments and biotas along the Chinese coasts. The total concentration of REEs (ΣREEs) in sediments was 41.65–170.94 mg/kg. The concentrations of ΣREEs were 1.97–4.77 and 0.62–4.96 mg/kg dry mass (DM) for oysters and mussels. The concentration of total light REEs (ΣLREEs) was higher than the concentration of total heavy REEs (ΣHREEs) at all samples. The bioaccumulation factor (BAF) of ΣLREEs was higher than ΣHREEs and BAF of ΣREE was 0.34–1.49 and 0.25–1.10 for oysters and mussels. The positive correlation between sediments and biotas was higher in mussels than oysters, showing a good potential for being environmental indicators for REEs. The risk of REEs to humans via oysters and mussels consumption could be negligible based on the estimated daily intake.

In this study, surface seawater was collected from 82 stations in the Drake Passage and Antarctic Peninsula sea area, and the distribution characteristics and correlations of 11 trace elements (i.e., V, Cr, Mn, Co, Cu, Zn, As, Mo, Cd, Pb, and U) in the seawater were analyzed. Results showed remarkable differences in the concentration of different elements, among which those of Mn (53.15%), Mo (22.77%), Zn (9.81%), and U (6.23%) were relatively high. The concentration of trace elements in Drake Passage water was relatively low, likely because a westerly drift that enhances large circulating currents exists in the sea area, thereby affecting the distribution of substances in the water. Mn, Co, Cu, Zn, Cd, and Pb showed relatively high concentrations at more stations than the other elements, and the high concentrations of Mn, Co, and Cd were mainly found in shallow water areas. UV, MoV, AsV, AsMo, AsU, and MoU demonstrated good linear correlations with correlation coefficients in the range of 0.878–0.961. These results could provide support for further explorations of the environmental behavior of trace elements in Antarctica.

Sustainable management of groundwater needs comprehensive study on water quality in present scenario. Hence, an understanding on the hydro geochemistry, saltwater intrusion, spatiotemporal-seasonal variations and irrigational suitability of groundwater becomes a must, especially in coastal regions. Our study area is one such place where all the parameters play a major role against sustainable management. The study pointed out that majority of the samples is brackish with two notable geochemical facies for pre monsoon and post monsoon. Factor and cluster analyses revealed that EC, TDS, Na⁺, Cl⁻, Mg²⁺ and Ca²⁺ are the major contributors. Gibb's diagram supported the dominance of rock weathering and evaporation in controlling the groundwater chemistry. Sea water intrusion was mapped using HFE diagrams and the Irrigational suitability is studied using USSL, SAR, %Na, etc. The data and results from this study might provide crucial information to water management authorities in dealing groundwater scarcity and pollution problems.

The agrochemicals and nutrient losses from farming areas such as paddy farming significantly dictate quality and eutrophication of the freshwater resource. However, how farming and land use pattern affect water qualities and eutrophication remain poorly understood in most African agro-ecosystems. The present study characterized how paddy farming influences water qualities and eutrophication in 10 irrigation schemes in Usangu agro-ecosystem (UA). About 42 water samples were sampled from intakes, channels, paddy fields, and drainages and analyzed for EC, Cl, P, NH₄-N, NO₃-N, TN, Zn, Cu, Ca, and Mg. We observed water pH ranging from 4.89 to 6.76, which was generally below the acceptable range (6.5–8.4) for irrigation water. NH₄-N concentration was in a range of 10.6–70.0 mg/L, NO₃-N (8.4–33.9 mg/L), and TN (19.1–21,104 mg/L). NH₄-N increased along sampling transect (sampling points) from intakes (5.7–29.1 mg/L), channels (19–20 mg/L), fields (12.9–35.8 mg/L), and outflow (10.6–70.0 mg/L), the same trend were found for NO₃-N and TN. The TP determined in water samples were in the range of 0.01 to 1.65 mg/L; where some sites had P > 0.1 mg/L exceeding the allowable P concentration in freshwater resource, thus indicating P enrichment and eutrophication status. The P concentration was observed to increase from intake through paddy fields to drainages, where high P was determined in drainages (0.02–1.65 mg/L) and fields (0.0–0.54 mg/L) compared to channels (0.01–0.13 mg/L) and intakes (0.01–0.04 mg/L). Furthermore, we determined appreciable amount of potentially toxic elements (PTEs) such as Cu, Pb, Cd and Cr in studied water samples. The high N, P, and PTEs in drainages indicate enrichment from agricultural fields leading to water quality degradation and contaminations (eutrophication). The study demonstrates that water quality in UA is degrading potentially due to paddy rice farming and other associated activities in the landscape. Thus, the current study recommends starting initiatives to monitor irrigation water quality in UA for better crop productivity, and improved quality of drainage re-entering downstream through the introduction of mandatory riparian buffer, revising irrigation practices, to include good agronomic practices (GAP) to ensure water quality and sustainability.

Sedimentary organic pollution in the urban reaches of the Thames estuary is changing from fossil fuel hydrocarbons to emerging synthetic chemicals. De-industrialisation of London was assessed in three cores from Chiswick (Ait/Eyot) mud island using pharmaceuticals, faecal sterols, hydrocarbons (TPH, PAH), Black Carbon (BC) and organotins (TBT). These ranked in the order; BC 7590-30219 mg/kg, mean 16,000 mg/kg > TPH 770–4301, mean 1316 mg/kg > Σ¹⁶PAH 6.93–107.64, mean 36.46 mg/kg > coprostanol 0.0091–0.42 mg/kg, mean of 0.146 mg/kg > pharmaceuticals 2.4–84.8 μg/kg, mean 25 μg/kg. Hydrocarbons co-varied down-profile revealing rise (1940s), peak (1950s -1960s) and fall (1980s) and an overall 3 to 25-fold decrease. In contrast, antibiotics, anti-inflammatory (ibuprofen, paracetamol) and hormone (17β-estradiol) increased 3 to 50-fold toward surface paralleling increasing use (1970s-2018). The anti-epileptics, carbamazepine and epoxcarbamazepine showed appreciable down-core mobility. Faecal sterols confirmed non-systematic incorporation of treated sewage. Comparison to UK sediment quality guidelines indicate exceedance of AL2 for PAH whereas TBT was below AL1.

In this study, we provide a baseline assessment of introduced marine species along the extensive (~600 km) Brazilian semiarid coast. We reported 27 introduced and 26 cryptogenic species. Moreover, the main vectors of introduction were ballast water, shipping lines, oil and gas activities, biofouling, and rafting on plastic debris. The taxa were Ascidiacea (17 species) and Bryozoa (17), followed by Crustacea (6), Mollusca (6), Cnidaria (3), Echinodermata (3), and Porifera (1). Among these invertebrates, some species are recognized as drivers of impacts such as the invasive corals (Tubastraea tagusensis and Tubastraea coccinea), the bivalves Isognomom bicolor and Perna viridis, the crab Charybdis hellerii, the brittle star Ophiothela mirabilis, and, finally, the bryozoan Membraniporopsis tubigera. These species threaten the biodiversity of unique ecosystems such as intertidal sandstone reefs, shallow-water coral reefs, and mesophotic ecosystems. Moreover, the up-to-date results highlight that this region is a hotspot of bioinvasion in the tropical South Atlantic.

Marine plastic pollution is one of the most talked about environmental issues of our time. While marine plastic pollution generally originates from mismanaged waste from land, waste from ships and fishing gear produce a unique threat to the global seas. Using a choice experiment, we explore preference for a marine debris removal and prevention programme focusing on derelict fishing gear. Additionally, we explore preferences for increasing removal efforts of debris in the North Western Hawaiian Islands. We find overwhelming support for these interventions; however, we find evidence that change, and therefore subsequent action, is strongest for individuals who believe that governments hold the majority of the responsibility for reducing and cleaning plastic pollution in marine environments.