Michele Arienzo

Tourism-associated coastal activities represent an important source of plastic-derived debris in tropical environments; however, baseline information on large microplastics (> 0.84 mm) remains limited in the Southern Gulf of Mexico. This study evaluated short-term variability in the composition and abundance of confirmed large microplastics in beach sediments from Playa Azul, Centla, Tabasco, comparing two contrasting visitation periods. Two 1-week monitoring campaigns representing low- and high-visitation conditions were conducted to assess changes in daily beach debris generation and large-microplastic characteristics. Results showed a marked increase in total beach debris during the high-visitation period, reaching values approximately 25-fold higher than those recorded during the low-visitation period. In contrast, confirmed large-microplastic abundance showed only limited short-term variation, while morphological composition differed between campaigns. Foams and fragments predominated during the low-visitation period, whereas films and fibres increased during the high-visitation period. Carbonaceous particles were recorded separately as non-plastic anthropogenic residues because their polymeric origin was not confirmed by FTIR. Polymer characterization using Fourier-transform infrared spectroscopy (FTIR) revealed high spectral matches for high-impact polystyrene (HIPS) in foams (95–98%), high-density polyethylene (HDPE) in fragments (90–95%), and polyethylene (PE) in fibres (90–92%). The Microplastic Pollution Index (MPPI) was interpreted as a descriptive screening indicator rather than as a definitive long-term pollution classification. Overall, the findings provide a short-term baseline indicating that visitor pressure was clearly associated with increased total beach debris, whereas large-microplastic abundance and morphology require broader temporal and spatial replication before robust long-term or causal conclusions can be drawn.

From the analysis of 11 sediment samples collected between 45.1 and 100 m water depth in the Gulf of Pozzuoli (Tyrrhenian Sea), upper circalittoral benthic foraminiferal and ostracod assemblages were investigated to evaluate the relationships between meiofaunal composition, abundance, diversity, and sediment contamination derived from industrial and residential sources. The bay has been affected by significant chemical pollution for over a century, and high concentrations of contaminants are still preserved in the sediments, raising concerns for ecological and human health. Some species, such as the benthic foraminifer Nonionella turgida and the ostracod Cytheroma variabilis, show a positive correlation with geoaccumulation indices, suggesting a potential tolerance to elevated contaminant concentrations. However, both benthic foraminifera and ostracods display high abundance and diversity, indicating that these assemblages are supported by moderately productive and non-stressed environmental conditions. Nutrient inputs likely enhance primary productivity and food availability, while remaining below levels that would induce hypoxia or toxic effects.,Comparison between the circalittoral assemblages analysed in this study and previously investigated infralittoral assemblages allows a clearer definition of taxonomic distribution across the infralittoral–circalittoral transition, contributing to a better understanding of the ecological gradients characterising the Gulf of Pozzuoli. This transition is marked by the occurrence of taxa not recorded above 40 m water depth, including the benthic foraminifera Quinqueloculina viennensis and Q. padana, and the ostracods Bosquetina tarentina, Buntonia dertonensis, Henryhowella parthenopea, Krithe praetexta, and Rectobuntonia subulata, together with a marked increase in the abundance of the genus Cytheropteron, which is rare in the shallow waters of the gulf.

The study evaluated the effect of monsoons on the levels of polycyclic aromatic hydrocarbons in the Hooghly River estuary sediments over 2018–2021. It was observed a cyclical enrichment of organic material, carbonate deposits, and clay over the post-monsoon and impoverishment over the monsoon because of the heavy rains and flood events. The mean total level of polycyclic aromatic hydrocarbons was 1682 ng/g with a wide range of variability depending on the season, 125–6518 ng/g, higher than previous assays and lower than a contemporary survey. Also, there was a marked predominance of the polycyclic aromatic hydrocarbon heavy pool, ~ 83%, with fluoranthene and pyrene making more than 40% of the total hydrocarbons loads and with a large variability of the composition with the monsoon. Concerning the numerical sediment quality guidelines, the mean individual compound levels, and ∑PAHs, do not surpass effect range low, effect range median, and apparent effects threshold limits and keep fairly below thresholds with no evidence of detrimental biological consequences. Temporal trends of polycyclic aromatic hydrocarbons split over two periods after the 2019 monsoon, with a sudden drop in hydrocarbon levels from two times for naphthalene, acenaphthylene, pyrene, benzo(a)anthracene, chrysene, to 6–7 times for phenanthrene, benzo(b)fluoranthene, benzo(a)pyrene, and indeno[1,2,3-cd]pyrene, with an overall decrease of ∑PAHs of threefold from 2948 to 959 ng/g. Monsoon seems to play as a sort of natural attenuation effect, slowing down river decline.

The study compared the pollution level of 16 priority polycyclic aromatic hydrocarbons (PAHs) in the superficial sediments of the low stretch of the Hooghly River, LSHR, with that of the Sundarbans wetland, SW. Mean total PAHs levels were concerning, with mean individual loads exceeding legal limits and literature references, indicating a worsening scenario compared to past surveys. The mean of ∑PAHs in LSHR was significantly higher than in the SW, 2,106 ng/g vs. 1179 ng/g, with a hot spot of 13,785 ng/g. Thus, it is especially in the river location that contaminants accumulate with five compounds concentrating at higher rates compared to the natural area, 103% (PHE), 86% (FLT), 122% (PYR), 156% (CHR), and 1500% (DhA). An evident dominance of the heavy pool (4 to 6 rings) was also observed with a sixfold higher load with respect to the light pool (2 to 3 rings), 1,413 vs. 266 ng/g. PAHs source screening by diagnostic ratios revealed the dominance of pyrogenic sources. Most of sediments of the low stretch present high toxicity risk, and urgent attenuation measurements are needed to improve the environmental state of the river and nearby wetland ecosystems.

This study presents the first data on a 2018–2021 campaign to monitor polycyclic aromatic hydrocarbon levels, PAHs, in the final stretch of the Hooghly River in West Bengal, India. The range of sedimentary PAHs was 0–47,366 ng/g, higher than the ranges given by the literature for comparable study areas. The assay reveals an outstanding level of PAHs contamination in the fine sediments of the Hooghly River and Sundarban wetland, where the dominance of 4–6 ring PAHs was 83% of the total. The diagnostic ratios based on molecular ratios of PAHs show that the pollution comes mainly from the combustion of petroleum. The ratio of anthracene relative to anthracene plus phenanthrene, ANT/(ANT + PHE), was >0.30, which is higher than the reference discriminant ratio of >0.10, suggesting that PAHs were from the combustion source. In the meantime, fluoranthene over the sum of fluoranthene plus pyrene, FLT/(FLT + PYR), was >0.5 and indicated coal combustion, in agreement with the literature. The mean level of carcinogenic hydrocarbons was at 18% of the total measured PAH, with a peak of 91%, revealing significant potential risk for humans and ecosystems. The toxicity equivalence factors, TEF, of the individual PAHs and the total BaP equivalent toxicity, TEQ, were adopted as a comparison reference of sediment quality. At most sites, toxic effect ranges were classified as high and very high. The results of this research call for public authorities to remedy a situation of severe ecological risk.

Microplastics, MPs, in aquatic environments pose serious threats when associated with other pollutants, such as pharmaceuticals, PHs. This review is a continuation of an earlier paper on the role of MPs as containers and carriers of heavy metals, HMs, persistent organic pollutants, POPs, pharmaceuticals, PHs, and personal care products, PCPs, in marine environments and published in the Journal of Marine Science and Engineering. The current effort aims to elucidate the most recent data on the interaction and association of MPs with PHs and the ecotoxicological implications on food webs. This review focuses on the nature of the interaction from different perspectives, such as the hydrophobicity and hydrophilicity of the polymer and drug, the polymer surface, and the rate of weathering. The effects of environmental conditions, such as mechanical stress, photodegradation, pH, salinity, dissolved organic matter, and gastrointestinal features of marine biota, were reported. This review reports on experimental laboratory, mathematical, and field data on MPs’ carrier and accumulation role in PHs and their release and ecotoxicological effects on water bodies. From the survey of the data, it emerges that the nature of the interaction and the effects on biota are very complex and variable, and perhaps only a systematic mechanic approach of data collection with a statistical approach using big data and deep learning will contribute in the future to clarify.

The review examines the most recent advances on the effect of persistent pollutants on sea turtles. Research on this topic is still limited, especially that related to toxicity, since they are protected species and in vivo toxicity studies are difficult, with most studies carried out on deceased individuals. Besides toxicology, the review considers direct links to pollution sources, reproduction impact, health effects and biomarkers of pollution exposure. Little attempts have been made so far to gather data that would provide insight into the causes of the observed health trends. Considering this, studies correlating PPs accumulation with health parameters were also discussed. The review synthesizes the recent progress of the research on these topics and indicates the main urgent need of investigation to limit threats from anthropic pressure.

Coastal erosion affects several beaches worldwide in association with natural and human pressures. In recent decades, the coastland located on the Paraíba do Sul River mouth has been recognized as one of the main areas that suffer from this geomorphological dynamic. Furthermore, the scientific literature, even if scarce, has pointed out that these dynamics are causing negative socio-environmental responses and making the area less resilient. In the last few decades, hundreds of homes and other urban structures have become debris due to erosion caused by sea ingression, triggered by the coupling of environmental processes and dynamics occurring at different spatial and temporal scales. Thus, the present research aimed to analyze how the anthropic changes carried out in the Paraíba do Sul hydrographic basin are related to the intense coastal erosion at the mouth. Variations in fluvial–marine hydrosedimentary dynamics triggered this due to the construction of dams to supply large cities and for agricultural purposes. Water and sediment samples were collected and analyzed in different sectors of the main channel and on the adjacent coast, mapping land use in the basin area and surveying socioeconomic data. The results suggest that human pressures on the hydrographic basin during the last century are directly associated with the imbalance of the environmental system and, consequently, the progression of coastal erosion on the Paraíba do Sul delta shoreline.

In the last decade, metal engineered nanomaterials (ENMs) have seen an exponential use in many critical technologies and products, as well an increasing release into the environment. Coastal ecosystems worldwide may receive ENM-polluted waters and wastes, with a consequent alteration of habitats and contamination of aquatic biota. There is a scarcity of data regarding the fate of these emerging contaminants in such environments. Open issues include the determination of the sources, the quantification of the interactions with marine sediments, the bioaccumulation pathways, the ecotoxicology on marine fauna and the identification of the principal biotic and abiotic factors that may alter metal ENMs toxicity. Little is known about their potential transference into the food web, as well toxicity features and co-stressors of single or multiple ENMs under laboratory and real environmental conditions for various taxonomic phyla. This review reports current knowledge on the ecological impact of ENMs under the complex environmental conditions of estuary systems, identifies gaps in current knowledge and provides directions for future research.