Sediment Contamination Research Articles

Refinement and Validation of the SPEcies at Risk Index for Metals (SPEARmetal Index) for Assessing Ecological Impacts of Metal Contamination in the Nakdong River, South Korea

The SPEcies At Risk index for metals (SPEARmetal index) was refined using updated physiological sensitivity data and validated to assess the ecological impact of metal contamination on benthic macroinvertebrate communities in the upper Nakdong River, near a Zn smelter in Korea. Biosurvey and chemical monitoring data were collected at 18 sites surrounding the smelter and nearby mines. Acute ecotoxicity tests on 20 indigenous species from the Korean peninsula were conducted and used to update taxon-specific metal sensitivity data. The refined SPEARmetal index, based on this updated sensitivity, was significantly lower than previous versions, with most values below the severe impact threshold (0.5) in the main stream. The correlation between hazard quotients in water and the SPEAR index improved, with the correlation coefficient increasing from 0.63 to 0.70. Despite consistently high benthic macroinvertebrate indices (BMIs) across the study area, generic ecological indices, such as total richness, EPT (Ephemeroptera, Plecoptera, and Trichoptera taxa richness), and Shannon’s diversity index, showed correlations with metal contamination levels. Principal component analysis identified the SPEARmetal index as the primary indicator associated with metal contamination in both water and sediment. These findings highlight the improved performance of the refined SPEARmetal index as a more sensitive and specific tool for assessing the ecological status of metal-impacted aquatic ecosystems compared to traditional indices.

Evaluation of 210Po, 210Pb, and potentially toxic element concentrations in aquatic environments and polychaetes along the southeast coast of Chennai, Tamil Nadu: a baseline report

ABSTRACT The activity concentrations of radionuclides (210Po and 210Pb) and the concentrations of potentially toxic elements (PTEs) in water, sediment, and two polychaete species (Marphysa madrasi and Namalycastis jaya) collected from 12 stations, denoted as S1 to S12, along the coast of Tamil Nadu, Chennai, in southeast India has been investigated. The average activity concentrations of 210Po and 210Pb were 0.39 ± 0.01 mBq/L and 3.30 ± 0.06 mBq/L in water, and 0.80 ± 0.02 Bq/kg and 4.21 ± 0.19 Bq/kg in sediment, respectively. Marphysa madrasi exhibited higher 210Po and 210Pb activity concentrations (37.78 ± 0.43 Bq/kg and 17.25 ± 0.22 Bq/kg, respectively) compared to Namalycastis jaya (34.40 ± 0.42 Bq/kg and 15.91 ± 0.26 Bq/kg, respectively). Maximum activity concentrations for both radionuclides in water were observed at Kalpaakam (S11) and Nemmeli (S7), while maximum sediment activity concentrations were found at Nemmeli (S7). The elevated activity concentrations in polychaetes from Nemmeli (S7) likely reflect the significantly higher 210Po and 210Pb activity concentrations observed in sediments from this site when compared to other sites. Bioaccumulation values for 210Po and 210Pb averaged 6.89 × 101 and 4.20 for M. madrasi, and 6.17 × 101and 3.84 for N. jaya , respectively. Sediment PTE concentrations followed the order: Fe > Zn > Mn > Ni > Co > Cr > Pb > Cd > Cu. Risk assessment indicated alarming levels of PTE contamination in sediments, suggesting severe anthropogenic impacts. In contrast, average PTE concentrations in polychaetes followed the order: Fe > Cu > Zn > Mn> Cr > Ni > Co > Cd > Pb. Statistical analysis revealed strong and significant correlations (p < 0.05) between PTE concentrations in sediments and polychaetes. The present study offers baseline data for evaluatingthe levels of 210Po and 210Pb in water, sediment, and polychaetes in selected locations along Chennai, Tamil Nadu, India’s southeast coast. These findings lay the groundwork for further studies of polychaetes, specifically the ecological effects of PTEs and radionuclides on coastal creatures and biomagnification.

Spatial distribution of heavy metal contamination and risk indices of surface sediments in high-altitude lakes.

Lake ecosystems in northern Pakistan are the most critical resources that maintain and regulate water flow for downstream agricultural, domestic, industrial, and ecological processes. One consequence of these processes is that ecosystems deposit heavy metals (HMs), where lake stagnant conditions result in high vulnerability of water resources. For this purpose, the present study examined HMs such as cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) concentrations in high-altitude lakes (HAL) sediments of Mansehra district, northern Pakistan. Sediment samples were collected from the five HAL. This study used HM concentrations in lake sediments for the pollution factors such as contamination factor (Cf), pollution load index (PLI), sediment pollution index (SPI), ecological risk assessment (ERA), and risk index (RI). Among HMs, Fe showed the uppermost levels of 1410mg/kg in lake sediment, while Cd with lowermost levels of 1.05mg/kg. Results revealed that most HM concentrations in HAL sediments were within the threshold of sediments quality guidelines (SQGs), except for Cd. Among lakes, the sediments of Siri Lake showed higher contamination of HMs than others. Siri Lake sediments also showed higher Cf, PLI, ERA, and RI values than others. The majority of HMs in HAL sediments showed no contamination, except for Cd (considerable) and Pb (moderate) levels to the exposed aquatic ecosystem. This study revealed that 95% of sediment samples in HAL were noted low to medium-level risks to the exposed aquatic communities. Statistical and geospatial analyses revealed that geogenic sources of contamination are a significant contributor to HM contamination of HAL sediments compared to others.

Integrated Assessment of Metal Contamination of Soils, Sediments, and Runoff Water in a Dry Riverbed from a Mining Area Under Torrential Rain Events

Dry riverbeds can transport mining waste during torrential rain events, disseminating pollutants from mining areas to natural ecosystems. This study evaluates the impact of these mine wastes on soils, sediments, and runoff/pore water in the La Carrasquilla dry riverbed (southeastern Spain). An integrated approach utilizing geochemical and mineralogical techniques was employed, analyzing water, soil, and sediment samples from both the headwater and mouth of the riverbed. Soil profiles and pore water were collected at 30 cm, 60 cm, and 90 cm deep, alongside sediment and runoff water samples. The assessment of metal(loid) contamination focused on arsenic, cadmium, chromium, copper, iron, nickel, manganese, zinc, and lead, utilizing sequential extraction to evaluate metal partitioning across soil phases. Various pollution indices, including the contamination factor (Cf), pollution load index (PLI), potential ecological risk index (RI), and metal(loid) evaluation index (MEI), were employed to classify contamination levels. The highest level of contamination was reported in the headwater, which suggested anthropogenic activities linked to the presence of mining residues as the major source of metal(loid)s. However, an active deposition of As, Cd, Cu, Fe, Mn, and Zn was reported in the topsoil at the mouth. In the headwater, a quartz and muscovite-rich zone exhibited the highest Cf for Pb (1022), primarily bound to the soil residual fraction (62.8%). At the headwater and mouth, pore water showed higher concentrations of sulfate, Ca, Na, Cl, Mg, and Mn and higher salinity than acceptable limits for drinking water or irrigation established by the World Health Organization. Runoff-water metal concentrations surpassed established guidelines, with MEI values indicating significant contamination by cadmium (36.1) and manganese (19.0). These findings highlight the considerable ecological risk of Pb and underscore the need for targeted remediation strategies to mitigate environmental impacts in the Mar Menor coastal lagoon.

Distribution and sources of polycyclic aromatic hydrocarbons in cascade reservoir sediments: influence of anthropogenic activities and reservoir hydrology.

The construction of dams has caused disruptions to river connectivity, leading to alterations in the deposition of hydrophobic organic contaminants in reservoir sediments. Further investigation is warranted to explore the impact of cascade reservoirs with differing hydrological characteristics on polycyclic aromatic hydrocarbons (PAHs) distribution in sediment. This study examines the presence of 30PAHs in the sediments collected from six cascade reservoirs situated in the Wujiang River basin during January and July 2017. The results showed that Σ30PAHs ranged from 455-3000ng/g dw (mean 1030ng/g dw). Anthropogenic activities and reservoir hydrology determined the distribution trend of PAHs in sediments, with an overall increase from upstream to midstream and then a decrease downstream. The PAH levels were highly linked to the secondary industry (P < 0.05). This was further supported by the relationship between the PAH emissions from coal combustion and traffic sources analyzed by the positive matrix factorization model and economic parameters in the wet season (P < 0.01). At the same time, reservoir age (RA) showed a positive correlation with PAH concentrations (P < 0.05), while hydraulic retention time (HRT) exhibited a negative correlation with PAH levels (P = 0.03). The relationship between total organic carbon (TOC) and PAHs in stream sediments worldwide was nonlinear (P < 0.01), with PAH concentrations initially rising and then falling as TOC levels increased. Concerns regarding carcinogenic risk were raised due to contributions from coal and vehicular sources, with the risk increasing with RA.

Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Sediments Along the Fluvial-to-Marine Transition Zone of the Don River

The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mCd) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River.

Arctic's hidden hydrocarbon degradation microbes: investigating the effects of hydrocarbon contamination, biostimulation, and a surface washing agent on microbial communities and hydrocarbon biodegradation pathways in high-Arctic beaches

BackgroundCanadian Arctic summer sea ice has dramatically declined due to global warming, resulting in the rapid opening of the Northwest Passage (NWP), slated to be a major shipping route connecting the Atlantic and Pacific Oceans by 2040. This development elevates the risk of oil spills in Arctic regions, prompting growing concerns over the remediation and minimizing the impact on affected shorelines.ResultsThis research aims to assess the viability of nutrient and a surface washing agent addition as potential bioremediation methods for Arctic beaches. To achieve this goal, we conducted two semi-automated mesocosm experiments simulating hydrocarbon contamination in high-Arctic beach tidal sediments: a 32-day experiment at 8 °C and a 92-day experiment at 4 °C. We analyzed the effects of hydrocarbon contamination, biostimulation, and a surface washing agent on the microbial community and its functional capacity using 16S rRNA gene sequencing and metagenomics. Hydrocarbon removal rates were determined through total petroleum hydrocarbon analysis. Biostimulation is commonly considered the most effective strategy for enhancing the bioremediation process in response to oil contamination. However, our findings suggest that nutrient addition has limited effectiveness in facilitating the biodegradation process in Arctic beaches, despite its initial promotion of aliphatic hydrocarbons within a constrained timeframe. Alternatively, our study highlights the promise of a surface washing agent as a potential bioremediation approach. By implementing advanced -omics approaches, we unveiled highly proficient, unconventional hydrocarbon-degrading microorganisms such as Halioglobus and Acidimicrobiales genera.ConclusionsGiven the receding Arctic sea ice and the rising traffic in the NWP, heightened awareness and preparedness for potential oil spills are imperative. While continuously exploring optimal remediation strategies through the integration of microbial and chemical studies, a paramount consideration involves limiting traffic in the NWP and Arctic regions to prevent beach oil contamination, as cleanup in these remote areas proves exceedingly challenging and costly.

The persistent DDT footprint of ocean disposal, and ecological controls on bioaccumulation in fishes

Globally, ocean dumping of chemical waste is a common method of disposal and relies on the assumption that dilution, diffusion, and dispersion at ocean scales will mitigate human exposure and ecosystem impacts. In southern California, extensive dumping of agrochemical waste, particularly chlorinated hydrocarbon contaminants such as DDT, via sewage outfalls and permitted offshore barging occurred for most of the last century. This study compiled a database of existing sediment and fish DDT measurements to examine how this unique legacy of regional ocean disposal translates into the contemporary contamination of the coastal ocean. We used spatiotemporal modeling to derive continuous estimates of sediment DDT contamination and show that the spatial signature of disposal (i.e., high loadings near historic dumping sites) is highly conserved in sediments. Moreover, we demonstrate that the proximity of fish to areas of high sediment loadings explained over half of the variation in fish DDT concentrations. The relationship between sediment and fish contamination was mediated by ecological predictors (e.g., species, trophic ecology, habitat use), and the relative influence of each predictor was context-dependent, with habitat exhibiting greater importance in heavily contaminated areas. Thus, despite more than half a century since the cessation of industrial dumping in the region, local ecosystem contamination continues to mirror the spatial legacy of dumping, suggesting that sediment can serve as a robust predictor of fish contamination, and general ecological characteristics offer a predictive framework for unmeasured species or locations.

Assessment of Water Status, Bottom Sediments, Macrophytes in the Light of Index Analysis and Geochemical Parameters of Selected Dam Reservoirs of Kielce Upland (Poland)

Concentrations of trace elements such as Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe were investigated in water, bottom sediments, and macrophytes (Phragmites australis and Typha latifolia L.) collected from the Borków, Wilków, and Rejów water reservoirs in the Kielce Upland (Poland). The main objective of this study was to investigate the condition of water, bottom sediments, and macrophytes in selected three sedimentary basins of the Kielce Upland and to identify natural and anthropogenic factors influencing this condition. The secondary objectives were (i) to determine the contents of trace metals in water, bottom sediments, and macrophytes, (ii) to assess the quality of abiotic and biotic elements of the ecosystem based on selected criteria, (iii) to compare reservoirs in terms of pollution, and (iv) to determine the ability of macrophytes to be used as a bioindicator of water/sediment pollution. Field tests were conducted in 2021. The trace metals in water were determined by ETAAS (Cr, Cd, Mn, Cu, Ni, Pb) and FAAS (Zn), and spectrophotometry method (Fe). The trace metals in sediments and macrophytes, including Cr, Zn, Cd, Co, Mn, Cu, Ni, Pb, and Fe, were detected using ICP-OES method. Contamination of bottom sediments with potentially toxic metals was determined based on the geo-accumulation index (Igeo), contamination factor (CF), and pollutant load index (PLI). Statistical analyses were performed using the Statistica PL 13.1. The analyses showed that the accumulation of trace elements in the surface layer of the reservoir sediments increases as follows: in Borków, Cd &lt; Co &lt; Ni &lt; Cu &lt; Pb &lt; Cr &lt; Zn &lt; Mn &lt; Fe; in Wilków, Cd &lt; Co &lt; Cu &lt; Ni &lt; Pb &lt; Cr &lt; Zn &lt; Mn &lt; Fe; and in Rejow, Cd &lt; Co = Cu = Ni = Pb &lt; Zn &lt; Cr &lt; Mn &lt; Fe. It was shown that the average distribution of metals in the bottom sediments of the studied reservoirs was as follows: Borków &gt; Wilków &gt; Rejów. Research has shown that the degree of trace metal accumulation increases as follows: water &lt; sediments &lt; macrophytes (except Pb from the reservoir in Borków).

Probing atomic-scale processes at the ferrihydrite-water interface with reactive molecular dynamics

Interfacial processes involving metal (oxyhydr)oxide phases are important for the mobility and bioavailability of nutrients and contaminants in soils, sediments, and water. Consequently, these processes influence ecosystem health and functioning, and have shaped the biological and environmental co-evolution of Earth over geologic time. Here we employ reactive molecular dynamics simulations, supported by synchrotron X-ray spectroscopy to study the molecular-scale interfacial processes that influence surface complexation in ferrihydrite-water systems containing aqueous MoO42-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {MoO}_4}^{2-}$$\\end{document}. We validate the utility of this approach by calculating surface complexation models directly from simulations. The reactive force-field captures the realistic dynamics of surface restructuring, surface charge equilibration, and the evolution of the interfacial water hydrogen bond network in response to adsorption and proton transfer. We find that upon hydration and adsorption, ferrihydrite restructures into a more disordered phase through surface charge equilibration, as revealed by simulations and high-resolution X-ray diffraction. We observed how this restructuring leads to a different interfacial hydrogen bond network compared to bulk water by monitoring water dynamics. Using umbrella sampling, we constructed the free energy landscape of aqueous MoO42-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {MoO}_4}^{2-}$$\\end{document} adsorption at various concentrations and the deprotonation of the ferrihydrite surface. The results demonstrate excellent agreement with the values reported by experimental surface complexation models. These findings are important as reactive molecular dynamics opens new avenues to study mineral-water interfaces, enriching and refining surface complexation models beyond their foundational assumptions.Graphic

Evaluation of Urbanization Influences on Beach Sediment Contamination with Heavy Metals Along the Littoral Zone of Alexandria City, Egypt

The western coastal area of Alexandria City, Egypt, faces significant environmental challenges due to heavy metal (HM) contamination in beach sediments, driven by intensive urbanization, tourism, commercial harbors, and industrial activities. Therefore, this study focuses on geochemically assessing HM levels in sediment samples from 28 sites and employed various descriptive and multivariate statistical approaches, pollution indices, and sediment quality guidelines (SQGs) to identify pollution hotspots, define contamination grades, and assess the quality of beach sediments. The average concentrations of Cd, Co, Cr, Cu, Pb, and Zn were 25.7, 30, 2.2, 7.5, 2.9, and 8.0 times, respectively, compared to the geochemical background (carbonate sedimentary rocks). et al.-Hanuvil Beach, relatively elevated contents of these metals were recorded. In addition, samples showed Zn levels higher than the corresponding probable effect concentration (PEC) and effect range medium (ERM) values, suggesting adverse impacts on biota. The principal component (PC) analysis revealed the anthropogenic origin of Cd, Co, and Pb in PC1, the mixed origin of Cr, Cu, Mn, and Zn in PC2, and the natural source of Fe in PC3. According to the applied single pollution indices, HM contamination grades were ranked in ascending order of Mn < Fe < Cr < Cd < Cu < Pb < Zn < Co. In conclusion, the HMs (Cu, Zn, Cd, Co, Pb, and Cr) in the study area are anthropogenic, attributed mainly to untreated discharge of municipal and industrial wastewater and solid wastes, atmospheric deposition of air pollutants, and tourism activities.

ОГЛЯД РЕЗУЛЬТАТІВ ДОСЛІДЖЕНЬ ЗАБРУДНЕННЯ КАХОВСЬКОГО ВОДОСХОВИЩА ЦЕЗІЄМ-137 І СТРОНЦІЄМ-90, ЯКІ ПРОВОДИЛИСЬ ПІСЛЯ АВАРІЇ НА ЧОРНОБИЛЬСЬКІЙ АЕС (1986-1921 РР.)

The available data on the state of radioactive contamination of water and bottom sediments of the Kakhovka Reservoir were analyzed in order to assess the possible deterioration of the quality of the environment based on the indicators of radioactive contamination in the zone of influence of the emergency discharge of water due to destruction of the Kakhovka NPP dam by the Russian military. Contamination of the Kakhovka Reservoir with 137Cs occurred mainly through the fallouts of this radionuclide with aerosols on the water surface in May 1986. A much smaller part of this radionuclide transported by water runoff directly from the headwaters of the Dnieper basin. Strontium-90 entered the reservoir exclusively by water pathway starting from October 1986. The steady trends of decreasing activity of both radionuclides in water has been observed since 1987. Approximately to 1996 137Cs activity concentrations had decreased to pre-accident level, 90Sr activity demonstrated a slow decrease and by 2022 remained slightly higher than pre-accidental level. The average levels of contamination of the Kakhovka reservoir bottom with 137Cs and 90Sr turned out to be the lowest compared to the other reservoirs of the Dnieper cascade. It was shown that in 1994 137Cs activity levels were 0.06 Ci/km2(2,2 kBq/m2) on 80% of the bottom surface (submerged former floodplain of the Dnieper) and were lower than on the territory adjacent to the reservoir. In the areas of silt accumulation (former channel of the Dnieper) 137Cs activity was on average three times higher. Balance calculations based on the data of radiation monitoring of water showed that the amount of 137Cs activity in the bottom sediments in the period 1987-2022 halved due to natural radioactive decay, the amount of 90Sr activity decreased by approximately 20%, since activity losses due to natural radioactive decay were partially compensated by the constant supply of this radionuclide with water runoff from the contaminated part of the catchment. After a catastrophic water leak from the reservoir, the Dnieper floodplain had exposed. According to the calculations, the average density of soil contamination of the ехposed areas with 137Cs does not exceed 0.03 Ci/km2 (1,1 kBq/m2), with 90Sr – less than 0.1 Ci/km2 (3,7 kBq/m2). Silt deposits of the former Dnieper channel, which had an increased level of 137Cs contamination, were re-suspended, probably, and carried out into the Dnipro-Bug estuary and further into the Black Sea. However, according to our assumptions, this should not have a negative effect on the radioecological state of the sea, because the 137Cs activity concentrations in the water of north-western part of the Black Sea were always 20-30 times higher than in the Dnieper water.

The character of Lake Kishkensor contamination in the area of underground nuclear explosions at the Semipalatinsk Test Site territory

The timely identification of areas where man-made radionuclides migrate through water streams is highly important for the territory of the former Semipalatinsk Test Site since the aquatic environment is currently a source of secondary contamination of environment. This article presents research findings on radioactively contaminated Lake Kishkensor located at the Semipalatinsk Test Site territory. As a result of this research, a new locally contaminated spot was discovered in the vicinity of the “Balapan” test site. Lake Kishkensor was found to be contaminated with man-made 3H and 90Sr. The 3H activity concentration in surface waters reached 430 kBq/L, and the concentration of 90Sr reached 100 Bq/L. In the sediments, the 3H activity concentration reached 700 kBq/kg, while that of 90Sr and 239+240Pu reached 310 Bq/kg and 250 Bq/kg, respectively. Ground water was found to be a source of surface water and sediment contamination. The monitoring results showed that the contamination level of the lake largely depended on the season and the inflow of contaminated ground water.

Contamination Assessment of Sediments and Bivalves in Estuaries of the Southern Iberian Peninsula

Human activities directly impact estuaries, where the biota is exposed to sediment contamination. A contamination assessment was carried out in several estuaries in the Southern Iberian Peninsula. Sediment samples were analyzed for the presence of metals/metalloids, and bioaccumulation tests were conducted with clams (Ruditapes philippinarum). Huelva Estuary had the highest contamination levels, while the inner bay of Cádiz and the outer stations of the estuaries from Guadiana, Guadalquivir, Palmones, and Guadarranque were the lesser contaminated. All sampling points (except Huelva) had low contamination levels of As and Cd, but they had high concentrations of Cu. The elements Pb, Cd, Zn, Cu, As, and Hg displayed correlations between the concentrations in sediments and the biota. High bioaccumulation of Zn, Cu, and As was observed in Huelva and Barbate. Important insights into the sediment contamination in Southern Iberian Peninsula estuaries suggest greater management and conservation efforts in these critical ecosystems.

Plasticizers: distribution and impact in aquatic and terrestrial environments.

Plasticizers, essential additives for enhancing plastic properties, have emerged as significant environmental and health concerns due to their persistence and widespread use. This study provides an in-depth exploration of plasticizers, focusing on their types, structures, properties, production methods, environmental distribution, and associated risks. The findings reveal that petroleum-based phthalates, particularly di-(2-ethylhexyl) phthalate (DEHP), are prevalent in aquatic and terrestrial environments, primarily due to the gradual degradation of plastic polymers. In the analysis of 39 studies on water contamination during the period of 2022-2023, only 22 works could be extracted due to insufficient details on the numerical value of plasticizer concentrations. Similarly, soil and sediment contamination studies were fewer, with only 11 studies focusing on sediments. These studies reveal that high plasticizer concentrations, notably in industrial and urban areas, often exceed recommended environmental limits, posing risks to ecological integrity and human health through bioaccumulation. Bioaccumulation of these compounds in soil and water could negatively affect the microbial communities, nutrient cycling, and could destabilize the overall ecological integrity. Concerns about their direct uptake by plants and potential risks to human health and food safety are highlighted in this study due to the high concentrations exceeding the threshold values. The review evaluates current treatment technologies, including metal-organic frameworks, electrochemical systems, multi-walled carbon nanotubes, and microbial degradation, noting their potential and challenges related to cost and energy consumption. It underscores the need for improved detection protocols, cost-effective treatments, stricter regulations, public awareness, and collaborative research to mitigate the adverse impacts of plasticizers on ecosystems and human health.

Assessment of Ecological Hazards in the Inaouen Wadi and Its Tributaries Using the Presence of Potentially Toxic Elements in Its Sediments

Inaouen wadi is the second largest tributary of the Sebou river, one of Morocco’s major rivers, which holds significant economic and social importance. Unfortunately, this watercourse is severely impacted by pollution from various human activities, particularly industrial sources. However, available data on the presence of potentially toxic elements (PTEs) that could harm human health in this region remain limited. PTEs pose major environmental risks due to their toxicity, persistence, and bioaccumulation. This study aimed to assess the concentrations of PTEs in the sediments of Inaouen wadi and its main tributaries based on sediment samples collected from 12 locations in 2019. The concentrations of Cd, Pb, Cr, Ag, Al, Cu, Fe, and Zn were measured using inductively coupled plasma atomic emission spectroscopy (ICP–AES), and sediment contamination levels were evaluated using multiple indices: the enrichment factor (EF), the geo-accumulation index (Igeo), the potential ecological hazard index (RI), and the modified ecological risk index (MRI). The results indicate that concentrations of Pb, Cd, Cr, Cu, Fe, and Zn are significantly influenced by urban discharges, particularly at sites S1, S3, and S5 near the cities of Taza and Oued-Amlil. The maximum values recorded were 7.01 g/kg for Pb, 0.9 g/kg for Cd, 0.1 g/kg for Cr, 19.9 g/kg for Fe and 1.9 g/kg for Zn. The enrichment factor (EF) revealed anthropogenic sources of Fe and Pb, confirming the human origin of these elements. The geo-accumulation index (Igeo) showed that the areas around stations S1, S3, and S5 are highly contaminated by Pb, Cd, and Fe, a finding also supported by the MRI. The study identified potential ecological risks at stations S1, S3, and S5, highlighting the urgent need for improved pollution management practices to mitigate environmental risks.

Trace element contamination biomonitoring: A comparative study between the polychaetes Alitta virens and Hediste diversicolor

Trace elements (TEs) remain of significant toxicological concern as many are critical for global decarbonisation. TEs accumulate in sediments so benthic polychaetes (e.g. Hediste diversicolor and Alitta virens) are highly relevant for ecotoxicology. However, ecological/biological differences could influence TE accumulation and biomonitoring suitability. Exploiting multiple sympatric populations (Solent, UK), we measure sediment and tissue concentrations generating EFs (enrichment factors), AEIs (Adverse Effects Indexes) and tissue bioaccumulation factors. We also assess stable isotope compositions to elucidate diet influences. Despite diverse anthropogenic activity in the Solent, the majority of TEs present low levels of sediment contamination at the sites. For Ni, Pb and As, a combination of mean AEIs >1 and some sediment concentrations exceeding SQVs (Sediment Quality Values) indicate a slight toxicological risk. For Cu and Hg, high EFs and AEI scores confirm they are the greatest risk, thus requiring source identification/control. However, only mean As tissue concentrations reflect contaminated sites, therefore, identifying the As-source(s) is also a priority. Sediment and tissue concentration relationships were generally negative and not significant for both species. Although a significant negative relationship for Cd for A. virens requires further investigation, the lack of evidence for TE bioaccumulation from sediment may limit both species' biomonitoring suitability for low-contamination sites. Species differences in tissue concentration were also TE specific: H. diversicolor had significantly higher concentrations for Ag, Cu, Hg, Ni and Zn, whilst the reverse was true for Cd, Fe, Cr and As. Whilst ecological differences and that feeding sources are site and species-specific (as evidenced by C, N and S stable isotopes analysis) cannot be ignored, the diverse tissue concentrations strongly suggest different TE regulation strategies per species. Together these data will be important for ecotoxicologists and regulators to select the ‘best’ polychaete biomonitor and assess TE toxicity under future global decarbonisation trajectories for TE inputs.

Evaluation and mitigation of potentially toxic elements contamination in mangrove ecosystem: Insights into phytoremediation and microbial perspective

Mangroves, essential coastal ecosystems, are threatened by human-induced Potentially-toxic-elements (PTEs) pollution. This study analyzed PTEs distribution, phytoremediation potential, and rhizosphere microbial communities in Taiwan's Xinfeng mangrove forest. Significant variations in physicochemical and PTEs concentrations were observed across adjacent water bodies, with moderate contamination in the river, estuary, and overlying water of mangroves sediment. The partition-coefficient showed the mobility of Bi, Pb, Co, and Sr at the water-sediment interface. The geochemical-indices revealed high Bi and Pb contamination and moderate Zn, Sr, Cu, and Cd contamination in sediment. The overall pollution indices indicated the significant contamination, while moderate ecological risk was found for Cd (40 ≤ Eri < 80). Mangroves Kandelia obovata and Avicennia marina exhibited promising PTEs phytoremediation potential (Bi, Cd, Mn, Sr, and Co). Metagenomics indicated a diverse microbial community with N-fixation, P-solubilization, IAA synthesis, and PTEs-resistance genes. These findings underscore the need for targeted conservation to protect these critical habitats.

Feeding of the crab Eriphia gonagra (Fabricius, 1781) (Decapoda: Brachyura: Eriphiidae) as a tool to assess the impacts of oil spills

ABSTRACT This study aimed to observe changes in the diet of crab Eriphia gonagra due to the oil spill that occurred in 2019 on two beaches on the Pernambuco coast (Gaibu and Carneiros Beach) Northeastern, Brazil. Changes in the species feeding were investigated considering the periods before, during, and after of the spill and correlated with the analysis of sediment contamination Polycyclic Aromatic Hydrocarbons (PAHs) and Trace Metals (TM). 160 specimens were analysed. 24 food items were found, with a prevalence of Mollusca (fragment) and Macroalgae in the diet. There was no detection of oil fragments in the stomachs of animals, however, different patterns were observed in the feeding of the species studied in the BEF, DUR, and AFT periods of the spill. A generalist habit, it was possible to observe changes in captured items, thus we observed a diet with low nutritional levels caused mainly in impacted environments. Two factors may be prevalent in explaining the impacts caused by the feeding of E. gonagra in Carneiros Beach. The first was the decrease in prey that died after the arrival of the oil, the second was the lasting effects of contaminants on the predation capacity of the species.

Environmental and human health risk associated with heavy metals in sediment of a tropical river in India

ABSTRACT Heavy metals persist in the sediment and can induce toxicological effects on living organisms. For analysing the risk of heavy metals, geochemical fractionation is beneficial. These geochemical fractions or speciations help to determine the heavy metals availability, mobility, toxicity, enrichment, and various risks. Here, we show how heavy metal contamination of sediment poses risks to both the ecosystem and human beings. We found significant Zn, Co and Cd contamination by analysing the geoaccumulation index. We also observed higher geoaccumulation index values for the pre-monsoon season than the post-monsoon one. Furthermore, pollution load index indicated gradual contamination of heavy metals in the sediments. This study's risk assessment and modified risk assessment codes showed low or no risk, but contamination factors indicated moderate to high risk. Our analysis of the effective range median mean quotient revealed some sampling stations as medium to high-priority sites. Similarly, probable effect level mean quotient designated some sampling stations as medium-low priority sites. We anticipated a moderate to significant mortality effect on the organisms from toxicity unit index values. Potential ecological risk index indicated a very high ecological risk on the Mahananda River. Furthermore, we predicted non-carcinogenic health hazards and carcinogenic health risks in the river's sediment.