During mining activities historically developed at Sierra Minera (Cartagena-La Unión, Spain), high amounts of trace elements were discharged to the Mar Menor coastal lagoon mainly through El Beal Wadi. The objective of this study is to establish the role played by the Cymodocea nodosa in the coastal marine dynamics of trace elements at the mouth of the wadi. To this end, the content of nine trace elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in different marine environmental compartments (i.e. marine and coastal sediments, C. nodosa tissues collected from live seagrass and C. nodosa beach cast litter) at two different locations were determined by inductively coupled plasma atomic emission spectrometry. The results showed that the seagrass C. nodosa could mobilise part of the elements present in marine sediments and water, thereby causing their re-accumulation in the coastal sediments through the C. nodosa beach cast litter.

Despite the beneficial aspect of aquatic food's consumption, bioaccumulation of toxic metals in fish can enhance the health risk for the consumers. Heavy metals were measured from editable tissues of some commercial fish species like Latis calcarifer, Silonia silondia, Clupisoma garua, Planiliza subviridis, Otolithoides pama, Tenulosa ilisa, Rhinomugil corsula, and Aila coila in the Meghna river estuary in Noakhali district. Heavy metals such as As, Pb, Cd, Cu, and Cr were detected by ICP-MS, which were significantly different (p ≤ 0.01), and the hierarchy of all mean concentrations were: Cu (5.14 mg/kg) > Pb (3.79 mg/kg) > As (1.08 mg/kg) > Cr (0.78 mg/kg) > Cd (0.12 mg/kg). The mean concentration of Cu (6.62 mg/kg) imparted to the maximum level in L. calcarifer, which slightly exceeded the Bangladesh food safety guideline. The mean BAFs of the contaminants were found as: Pb (1042.29) > Cr (1036.47) > As (934.84) > Cd (832.77) > Cu (772). Further, L. calcarifer, S. silondia, C. garua, and P. subviridis showed the bioaccumulative status. To assess the health risk effects, estimated daily intake (EDI), target hazard quotient (THQ) and carcinogenic risk (CR) were conducted. THQs for both adult and children consumers were <1, indicating that, consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, CR for all the consumers was found in the acceptable range (10⁻⁶ to 10⁻⁴).

The benthic foraminiferal diversity index was computed from Beypore estuary sediments. The abundance and diversity of Quinqueloculina lata, Textularia agglutinans, Haplophagmoides canariensis, and Quinqueloculina stelligera were dominated by stress-tolerant taxa such as Ammonia tepida, A.parkinsoniana, Nonion grateloupi, and N. scaphum in the estuary. The small-size foraminifera probably perished in a juvenile stage because of the high temperature and low salinity that prevailed in the ecosystem. The dominance of stress tolerant benthic foraminifera and absence of Elphidium species in the estuary suggest the prevalence of hypoxic (low-oxygen) conditions. The consistent low-diversity index of foraminifera indicates that the ecosystem is moderate to highly stressed ecologically in the Beypore estuary. The application of benthic foraminifera as a bioindicator for assessing the environmental stress in the Beypore estuary is key in monitoring these fragile coastal ecosystems.

The levels, vertical distribution and sources of hydrocarbons and petroleum biomarkers were estimated for the first time in sediment cores (0–40 cm) from ten coral Islands of the Persian Gulf, Iran. Discrepant hydrocarbons, including linear n-alkanes (n-C₁₁ to n-C₄₀) and isoprenoids (AHs), aliphatic ketones (AKs), hopanes and steranes were measured in all core samples, showing mean concentrations ranging from 209 to 5388 μg g⁻¹dw (∑₃₀AH), 2–244 μg g⁻¹-dw (∑₁₃AK), 189–3713 ng g⁻¹dw (∑₃₁hopane) and 42–3864 ng g⁻¹dw (∑₁₅sterane), respectively. All sediment cores were found to be petroleum polluted, with ∑₃₀AH > ∑₃₁hopane > ∑₁₅sterane > ∑₁₃AK, with higher levels recorded at 10–20 cm, mainly at industrial sites. Various diagnostic indices revealed that hydrocarbons derived mainly from anthropogenic inputs, with significant contribution of biogenic origin at sites less polluted. Moreover, total organic carbon (0.24–23.45 mg g⁻¹-dw), terrestrial and marine organic matter had an overwhelming effect on hydrocarbons deposition in sediment cores. Overall, findings provide relevant information for monitoring and preventing petroleum pollution in the sensitive ecosystems of the Persian Gulf.

Polycyclic aromatic hydrocarbons (PAHs) are toxic and ubiquitous in the environment and pose great risks. Bioaccumulation by plankton is the outset for PAHs entering marine food web. The long-term driving environmental factors for bioaccumulation of PAHs in zooplankton have not been well investigated. In this study, high variation of PAH concentrations in zooplankton (5 to 5440 ng g⁻¹ dry weight) was found, with the highest PAH levels near the transect Kaohsiung Harbor. Precipitation significantly enhances the PAH concentration in zooplankton and affects the PAH distribution in the water column, indicating PAH input from terrestrial runoff. The sources of PAHs in the coastal waters are a mixture of petroleum and combustion. Biomass dilution dominates bioaccumulation of PAHs in zooplankton, especially for the dominant species, copepods. This study provides the first information on PAH bioaccumulation in zooplankton to understand PAH transport in the plankton food web in subtropical coastal waters.

Being globally and locally prevalent, beach litter has been monitored at 29 sites along the German North Sea coastline. This study offers an exploratory analysis of data from 1991 to 2016. Schleswig-Holstein exhibited lower mean litter pollution levels than Lower Saxony, possibly because the locations in Lower Saxony are situated along the main coastal current, whereas the North Frisian Islands act as a barrier for the mainland sites in Schleswig-Holstein. Locations close to the Elbe estuary had significantly larger amounts of debris, likely receiving litter from marine and riverine sources. No clear overall pattern in litter abundance or composition could be detected. Significant quantitative similarities between debris types were inconsistent. The effect of wind, tides, and exposure appeared to be marginal. Recurring data inconsistencies, gaps, and outliers were partly attributed to human error. This could be reduced through hypothesis-driven monitoring with a simpler litter classification and continuous data checking.

Cadmium has had a number of historical applications in plastics but is now highly regulated. In this study, plastics containing pigmented or recycled Cd at concentrations up to 16,300 μg g⁻¹ were processed into microplastic-sized fragments and added to clean estuarine sediment. Plastic-sediment mixtures (mass ratio = 1:100) were subsequently exposed to fluids simulating the digestive conditions encountered in marine deposit-feeding invertebrates prepared from a protein and a bile acid surfactant in seawater and the mobilization of Cd measured as a function of time. Kinetic profiles over a six-hour period were complex, with some fitted using a diffusion model and others exhibiting evidence of Cd interactions between the plastic and sediment surface. The maximum concentration of Cd released from plastic-sediment mixtures was about 0.8 μg g⁻¹ and orders of magnitude greater than Cd mobilization from sediment alone. It is predicted that large communities of deposit-feeders could mobilize significant quantities of Cd from historical microplastics.

Plastic pollution is a pervasive problem to marine life. This study aimed (1) to investigate levels of microplastic in wild and farmed mussels (Perna perna), and (2) to assess the effectiveness of depuration in reducing microplastics. Wild and farmed mussels were sampled from Guanabara Bay (Southwestern Atlantic). Four treatments were compared (N = 10 mussels/treatment): wild non-depurated mussels, wild depurated mussels, farmed non-depurated mussels, and farmed depurated mussels. Up to 31.2 ± 17.8 microplastics/mussel (≥0.45 μm) were detected (means ± SD), and microplastics were present in all 40 individuals analyzed. Nylon fibers were more abundant than polymethyl methacrylate (PMMA) fragments. Blue, transparent, and red nylon fibers were more abundant in both wild and farmed mussels. Although 93 h-depuration significantly reduced microplastics (ANOVA, p = 0.02) in both wild (46.79%) and farmed mussels (28.95%), differences between farmed and wild mussels were not significant (p > 0.05). Depuration was more effective in removing blue fibers. Our results highlight the importance of depuration in reducing microplastic pollution in seafood.

Marine debris is an economic, environmental, human health, and aesthetic problem posing a complex challenge to communities around the globe. To better document this problem in the Gulf of Mexico we monitored the occurrence and accumulation rate of marine debris at twelve sites on nine barrier islands from North Padre Island, Texas to Santa Rosa, Florida. With this information we are investigating three specific questions: (1) what are the major types/sources of marine debris; (2) does debris deposition have seasonal oscillations; and (3) how does debris deposition change spatially? Several trends emerged; plastic composed 69–95% of debris; there was a significant increase in debris accumulation during the spring and summer seasons; accumulation rates were ten times greater in Texas than the other Gulf States throughout the year; and the amount of debris accumulating along the shoreline could be predicted with high confidence in areas with high freshwater influx.

Macrozoobenthos living around several pipelines placed at different depths and sediment types in the Western Adriatic Sea was investigated for three years after structures' deployment to detect possible effects due to their installation and presence. Three environmental habitats were considered based on the grain size (silty clay, clayey silt and sand). Samplings were taken within a radius of 100 m from the pipelines and at control sites. Multivariate and univariate analysis showed peculiarities of the three habitats due to the different sediment type, without differences between pipelines and controls inside each group. Silty clay and clayey silt communities appeared quite similar, being mainly represented by opportunistic species typical of the Adriatic coastal area. Benthic populations found at the offshore relict sand were characterized by a higher percentage of sensitive species. Independently of sediment typology, pipelines' installation seems to not affect the benthic populations that appear more influenced by environmental features.