Assessment of heavy metal pollution in marine sediments from southwest of Mallorca island, Spain

Risk assessment and contaminant characterization of PCBs, PAHs, and heavy metals in Pichavaram mangrove sediments, Tamil Nadu, India

The coastal region of Pichavaram, Tamil Nadu, India, is a critical ecological zone that supports diverse marine life and local livelihoods; however, it faces significant environmental challenges due to contamination from persistent toxic substances (PTSs) and heavy metals, which pose serious ecological and human health risks. In the present study, sediment samples collected from the mangrove environment were tested for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals. The results revealed elevated concentrations of ∑PCBs (6-124 ng/g) and ∑PAHs (3.19-37.8 ng/g), alongside heavy metals such as Pb (11-26 μg/g), Cd (0.3-0.87 μg/g), Cu (below detectable levels, bdl)-31 μg/g), Ni (bdl-119 μg/g), and Zn (27-109 μg/g), indicating significant environmental contamination. The total PCB concentrations surpassed the guideline values, indicating potential risks to aquatic life. Elevated naphthalene levels in Kodipallam suggest petrogenic inputs from oil spills and urban runoff. Carcinogenic PAHs, including benzo[a]pyrene, are found at high levels in industrial zones such as Killai, and pose moderate ecological risks. Heavy metals such as As (68-140 μg/g), Cr (25-120 μg/g), and Mn (94-471 μg/g) often exceeded the threshold effect levels (TEL) and probable effect levels (PEL), indicating significant ecological risks and potential human health impacts. Coastal sediment contamination, driven by discharges from chemical industries, oil refineries, metal manufacturing, and agricultural runoff, poses long-term risks to marine life and human health through the bioaccumulation of persistent pollutants in the food chain. This study provides crucial baseline data for future monitoring and emphasizes the need for stricter regulatory measures and pollution management strategies. Recommendations include regular sediment quality monitoring, public awareness campaigns on pollution sources, and sustainable practices to mitigate risks, thereby protecting the coastal environment and local communities.

Assessing the heavy metal contamination and health risks in riverine sediments using multi-index analysis: insights from east coast of Tamil Nadu, India

The research article appraises the environmental pollution status and health risk assessments associated with heavy metal concentration in the Gadilam (study site I) and Uppanar (study site II) river surface sediments within the quaternary formation, part of Kallakurichi and Cuddalore district, Tamil Nadu, India. By analyzing the heavy metal concentration and environmental pollution zone and health risk assessments, the outcome fosters the insights of an intensifying risk to riverine regions and their ecological implications due to anthropogenic activities. Totally 27 sediment samples were collected from study sites I and II to assess the contagion status of the sediments and monitor the riverine environment. Heavy metal (Fe, Al, Ti, Mn, Cu, Zn, Ni, Pb, and Cr) concentrations were determined in surface sediments, addressing the influences arising from anthropogenic activities. To decipher the pollution status, the pollution monitoring indices, like geoaccumulation indices (Igeo), enrichment factor (Ef), contamination factor (Cf), degree of contamination (Cd), and modified degree of contamination (mCd), pollution load index (PLI), potential ecological risk indices (PERI), and sediment quality guidelines (SQGs) such as mean effects range median quotient (MERMQ), toxic risk index (TRI), and modified hazard quotient (mHQ), were used in the study area. Health hazard assessment stated non-carcinogenic risk and carcinogenic risk were analyzed for adults and children in study sites I and II. Subsequently, statistical analysis were performed. The outcome possessed the pollution assessment of study site I (location - 05 and 06) and study site II (location-03), which implies that they are extremely polluted and have high potential adverse biological effects. This study emphasized the non-carcinogenic risk assessment of hazard index (HI) for study sites I and II sediments shown to be endangered to adults and children in the surrounding region. Furthermore, the carcinogenic risk assessment accounted for no hazards for adults and children in the study site. This study revealed heavy metal contamination in the Cuddalore district, likely arising from industrial effluents, residential wastages, and anthropogenic activities in the surface sediments of riverine environment, and it provide insights into health risk assessment and environmental pollution status to foster the local communities' awareness and an invaluable dataset to generate environmental safety management measures.

Spatial distribution, contamination levels, and risk assessment of heavy metals along the Eastern India coastline

The proposed comprehensive study was accomplished to analyze the ecological phenomenon, heavy metals occurrence, and its significance. The spatial distribution of heavy metals in the sediments such as Cadmium (Cd), Cobalt (Co), Cupper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni), Zinc (Zn), Iron (Fe), and Chromium (Cr) of the Eastern coastline of India (ECI) was evaluated across 61 sites along the 1400 km stretch of the Bay of Bengal and the Arabian Sea coastline. The heavy metal concentration was higher for Hg (0.08 μg/g) and Cd (3.44 μg/g), likely due to mining and extraction activities. Strong positive correlations (R2>0.5,p<0.01) observed between Cd∼Fe R2=0.70, Cd∼-Cr R2=0.68, Co∼Zn R2=0.79, Cu∼Ni R2=0.73 suggesting co-miming sources while negative correlations Ni∼Cr R2=-0.50, Ni∼Pb R2=-0.56, Cu∼Pb R2=-0.58 indicate the separation of these metals in sediments due to geochemical conditions and tailing disposal. The heavy metals, Co, Cu, Pb, Ni, Fe, and Cr were under the concentrations proposed by sediment quality guidelines (SQGs). It indicated there is fewer immediate effects of heavy metals, however, even at low levels metals like Hg, Cd, and Pb can cause chronic exposure effects, bioaccumulation and subclinical health impacts over time. The stations of Utkal (UC 14-UC 18) and Coromandel (CC 8-CC 11) coastline act as shipping ports and are involved in mining activities and recorded geological weathering of rocks in these areas, compared to other sampling locations along Utkal, Andhra and Coromandel coastline.

Heavy metal contamination in seawater, sediments, algae, and fish from Susah and Tobruk, Mediterranean Sea

Heavy metal contamination in marine environments poses serious threats to ecological health and human safety. This study examines the concentrations of zinc (Zn), copper (Cu), iron (Fe), cadmium (Cd), and lead (Pb) in sediments, seawater, and marine organisms (Ulva lactuca and Epinephelus marginatus) along the coastlines of Susah and Tobruk, Libya. The sampling involved 66 samples from 10 sites conducted in winter 2023. The contamination of cadmium clearly showed in all studied samples in Susah and Tobruk, whereas lead surpassed permissible in seawaters and livers, gills, and tissues of E. marginatus. The iron was high in the seawaters of Susah and Tobruk, particularly near Susah port and in Tobruk Gulf, reflecting the influence of industrial and anthropogenic activities. The results revealed that cadmium levels in the sediments indicated considerable contamination in Susah (CF = 5.897) and moderate contamination in Tobruk (CF = 1.12). The assessment employed several pollution indices, including the Geo-accumulation Index (Igeo), which indicated that all studied metals were uncontaminated in Tobruk, while Cd showed moderate contamination in Susah (Igeo = 1.975). The Nemerow Pollution Index (NI) categorized Susah as seriously polluted (NI = 6.01) and Tobruk as lightly polluted (NI = 1.195). Additionally, bioaccumulation factors for heavy metals in both U. lactuca and E. marginatus indicated acute contamination, particularly lead in fish tissues. These findings underscore the urgent need for effective environmental management strategies to address heavy metal pollution and protect the health of marine ecosystems and local communities reliant on these coastal resources. PRACTITIONER POINTS: Comprehensive pollution profiling (CF, Igeo, NI, and EF) in the study areas. GIS spatial mapping (heavy metal distribution and pollution sources identification) Bioaccumulation insights (bioaccumulation in fish and algae, showing ecological risk). Data for future monitoring (data for a significant gap in environmental monitoring) Public health awareness (urgent need for management and treatment options).

Silicon Speciation and Its Relationship with Carbon and Nitrogen in the Sediments of a Macrophytic Eutrophic Lake

Silicon (Si) is one of the biogenic elements in lake aquatic ecosystems. Sediments are both sinks and sources of Si, but little is known about its influence on the biogeochemical cycle of Si in lakes and its relationship to other biogenic factors such as carbon and nitrogen. Examining Caohai Lake, a typical macrophytic lake in China, this study systematically examined the different Si forms and biogenic silica (BSi) distribution characteristics and their coupling relationships with total organic carbon (TOC) and total nitrogen (TN) in surface sediments. Iron-manganese-oxide-bonded silicon (IMOF-Si) and organic sulfide-bonded silicon (OSF-Si) jointly accounted for 95.9% of Valid-Si in the sediments, indicating that the fixation of Si by organic matter and iron-manganese oxides was the main mechanism underlying the formation of the different forms of Valid-Si in sediments. The release and recycling of Si in sediments may be mainly driven by mineralized degradation of organic matter and anoxic reduction conditions at the sediment-water interface. The content of biogenic Si (BSi) in the sediments was relatively higher in the southern and eastern areas, which could be explained by the intensification of eutrophication and the increased abundance of diatomaceous siliceous organisms in these areas seen in recent years. The TOC and TN contents in the sediments were generally high, and the sources of organic matter in the sediments included both the residues of endophytes (main contributors) and the input of terrigenous organic matter. TOC and TN both had highly significant correlations with OSF-Si and Valid-Si, which demonstrated that Valid-Si had excellent coupling relationships with C and N in the sediments. The good correlation between BSi, TOC and TN (p < 0.01), as well as the high C/Si, N/Si mole ratio of TOC and TN to BSi, respectivelny, indicating that the dissolution and release rate of BSi may be much higher than the degradation rate of organic matter from the sediments, especially in the areas with a higher abundance of siliceous organisms.

Determination of Heavy Metal Levels and Assessment of L. monocytogenes and Salmonella spp. Presence in Fishery Products and Mussels from the Marmara Region, Türkiye

This study evaluated heavy metal levels (Pb, Cd, Hg, As, Cu) and the presence of Salmonella spp. and Listeria monocytogenes in mussels and commonly consumed fishery products from the Marmara region of Türkiye. Health risks were evaluated using total hazard quotient (THQ) and hazard index (HI) values, while microbial risks in fresh and ready-to-eat (RTE) products were estimated via the Risk Ranger tool. Among 625 samples, Hg (36.96%; CI95 = 33.27-48.81), Pb (9.76%; CI95 = 7.67-12.34), and Cd (19.36%; CI95 = 16.45-22.64) exceeded permissible limits, except in crabs, which remained compliant. Anchovy, sardines, bluefish, shrimps, and octopus met EU Cd limits. Shrimps exhibited higher Asin levels than crabs (p < 0.05), while squids had significantly higher Asin than octopus but lower Pb (p < 0.05). Microbiological analysis detected Salmonella spp. in 4.00% of samples (CI95 = 2.50-6.30) and L. monocytogenes in 4.24% (CI95 = 2.70-6.59). Surmullet, bluefish, red mullet, crabs, mussels, and octopus tested negative for both, while anchovy was negative for Salmonella spp. only. THQ and HI assessments emphasized the need for environmental monitoring to mitigate heavy metal contamination. The detection of pathogens highlights the importance of stringent surveillance measures to ensure the safety of fishery products and bivalves.

Impact of Lead Pollution from Vehicular Traffic on Highway-Side Grazing Areas: Challenges and Mitigation Policies

One major environmental concern is the lead (Pb) pollution from automobile traffic, especially in highway-side grazing areas. Sheep grazing in Pb-contaminated areas are particularly vulnerable because Pb exposure from soil, water, and feed can have harmful effects that impair their general health, reproductive capability, and immune systems. Long-term hazards to cattle from persistent Pb exposure include neurotoxicity, hematological abnormalities, reproductive health problems, and immunosuppression. These can have serious consequences, such as reduced productivity and even mortality. Additionally, through the food chain, Pb bioaccumulation in lamb tissues directly endangers human health. Pb poisoning is caused by a variety of intricate mechanisms, including disturbances in calcium-dependent processes, oxidative stress, and enzyme inhibition. To mitigate these risks, an interdisciplinary approach is essential, combining expertise in environmental science, toxicology, animal husbandry, and public health. Effective strategies include rotational grazing, alternative foraging options, mineral supplementation, and soil remediation techniques like phytoremediation. Additionally, the implementation of stringent regulatory measures, continuous monitoring, and community-based initiatives are vital. This review emphasizes the need for comprehensive and multidisciplinary methodologies to address the ecological, agricultural, and public health impacts of Pb pollution. By integrating scientific expertise and policy measures, it is possible to ensure the long-term sustainability of grazing systems, protect livestock and human health, and maintain ecosystem integrity.

Emerging contaminants in the Mediterranean Sea endangering Lebanon's Palm Islands Natural Reserve

The Mediterranean Sea is an intercontinental marine environment renowned for its biodiversity and ecological significance. However, it is also one of the most polluted seas globally with significant levels of microplastics and heavy metals among other emerging contaminants. In Lebanon, inadequate waste management infrastructure and unregulated industrial discharges have exacerbated water quality deterioration by introducing these complex contaminants into surface and seawater. The Palm Islands Natural Reserve in Lebanon is a UNESCO-designated marine protected area and home to endangered species. However, the reserve faces significant threats from pollution, including heavy metals and microplastics, exacerbated by nearby Tripoli's escalating contamination. Plasticisers, particularly phthalates, are recognized for their hormone-disrupting effects, and heavy metals like cadmium, lead, and arsenic pose severe eco-toxicological risks. This study investigates the levels of heavy metals and phthalates in water and sediments from the Palm Islands. Samples were collected from different locations within the reserve, and heavy metals and phthalates were detected, including chromium (13.58 to 19.28 μg L-1), arsenic (2.05 to 5.04 μg L-1), cadmium (1.27 to 3.04 μg L-1), and lead (0.92 to 2.88 μg L-1). Cadmium levels exceeded the permissible limits set by environmental regulatory bodies, highlighting an urgent pollution problem. Phthalates, including DEP and DEHP, were also detected in concentrations of 7.12-10.25 μg L-1 for DEP and 38.47-56.12 μg L-1 for DEHP raising concerns over their potential eco-toxicological impact on marine species. Our research underscores the need for comprehensive environmental monitoring, better waste management infrastructure, and stricter regulatory measures to address pollution in Lebanon's coastal ecosystems.

Spatial distribution of heavy metal assessment in beach sediment due to bauxite mining in Kuantan, Pahang, Peninsular Malaysia

The effect of open-pit bauxite mining on beach sediment contamination in the urban coastal environment of Kuantan City, Malaysia, was investigated. The contents of 11 heavy metals (Pb, Cd, Al, Mn, Cu, Zn, Fe, As, Ni, Cr, and Ag) in 30 samples from Kuantan beach sediment zones (supratidal, intertidal, and subtidal) were determined using inductively coupled plasma optical emission spectrometry followed by contamination indexes, Pearson's correlation analysis, and principal component analysis (PCA). The results indicated that Cd, As, Ni, and Ag values in beach sediment zones were significantly higher compared to background values. Contamination indexes suggest that Cd, As, Ni, and Ag were highly contaminated, and moderate to extremely enriched near the Kuantan Port. However, these heavy metal concentrations are lower compared to previous studies in the region. Sediment quality guidelines highlighted the occasional presence of Cd and Ag. Based on Pearson's correlation analysis, PCA, and cluster analysis, sources of these heavy metals in beach sediments were likely from agricultural runoff, uncontrolled industrial and residential discharge, and unprotected mine waste near the Kuantan Port. Furthermore, effective management of mining practices and ongoing monitoring are essential to reduce contamination risks.

Spatial distribution, ecological and human health risks of potentially toxic elements (PTEs) in river Ravi, Pakistan: A comprehensive study

Significant quantities of potentially toxic elements have been and are still being discharged into Pakistan's rivers through natural sources and anthropogenic activities. The present study provides a comprehensive study of potentially toxic element contamination in the water and sediment of the Ravi River, Pakistan. The research aims to examine the extent of pollution, its ecological risks, and the potential human health impacts through detailed geospatial analysis and statistical correlation. Water and sediment representative samples were taken and analyzed for potentially toxic elements, including Cobalt (Co), Cadmium (Cd), Zinc (Zn), Nickel (Ni), Arsenic (As), Chromium (Cr), Lead (Pb), Copper (Cu), and Manganese (Mn). Various pollution indices, such as the "Geo-accumulation Index (Igeo), Modified degree of Contamination (mCd), Nemerow comprehensive pollution index (Pt), Contamination factor (CF), Enrichment factor (EF), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI)," were calculated to determine the contamination levels and ecological risks. The results indicated significant spatial variability in metal concentrations, with higher levels observed in industrial and urban areas (near Lahore). Cd and As were identified as the most critical pollutants, exhibiting high Igeo, CF, EF, and PERI values. The PLI revealed that several regions along the river are heavily polluted. Pt shows high comprehensive pollution near Lahore and moderate to high pollution in surrounding areas. According to mCd, most of the study area, especially sampling points near Lahore, ranges between 8 and 16, indicating a high degree of pollution. The Human Health Risk (HHR) assessment, considering ingestion, inhalation, and dermal contact pathways, highlighted that children are particularly vulnerable, showing higher Hazard Quotient (HQ) and Hazard Index (HI) values for several metals. Correlation analysis revealed significant relationships between certain metals, suggesting common sources of contamination, likely from industrial discharges and urban runoff. The comprehensive mapping and statistical analysis underscore the urgent need for implementing effective pollution control measures to mitigate the risks posed by potentially toxic element contamination in the Ravi River. This study provides critical insights for policymakers and environmental managers to prioritize areas for remediation and to develop strategies to protect both ecological and human health in the region.

Identification and Assessment of Toxic Substances in Environmental Justice Cases

This study assessed heavy metal contamination in industrial solid waste (S1, S2, S3, and S4) from the Yangtze River Delta region, employing nine risk assessment methods including total content indices (e.g., Igeo, CF) and speciation indices (e.g., ICF, GCF). Four types of industrial solid waste not classified as hazardous but containing heavy metals were analyzed. Key findings revealed significant variability in risk assessments based on chemical speciation versus total content. For example, while S1, S3, and S4 exceeded background levels, S4 showed higher mobility of Pb, Cr (VI), Cu, Ni, and As despite lower overall content. Elements like Cd and Cr (VI) exhibited discrepancies between total content and speciation-based assessments due to low background values and high toxicity. Multi-element indices (DC, RI) indicated higher pollution degrees compared to speciation indices (GCF, GRI). These results underscore the need for integrating multiple assessment methods to accurately evaluate environmental risks in judicial practices.

Using Sediment Bacterial Communities to Predict Trace Metal Pollution Risk in Coastal Environment Management: Feasibility, Reliability, and Practicability

The distribution of trace metals (TMs) in a continuous water body often exhibits watershed attributes, but the tidal gates of the coastal rivers may alter their transformation and accumulation patterns. Therefore, a tidal gate-controlled coastal river was selected to test the distribution and accumulation risks of Al, As, Cr, Cu, Fe, Mn, Ni, Sr, and Zn in the catchment area (CA), estuarine area (EA), and offshore area (OA). Associations between TMs and bacterial communities were analyzed to assess the feasibility of using bacterial parameters as ecological indicators. The results showed that As and Cr were the key pollutants due to the higher enrichment factor and geoaccumulation index, reaching slight to moderate pollution levels. The Nemero index was highest in EAs (14.93), indicating a higher pollution risk in sediments near tide gates. Although the TM dynamics can be explained by the metal-indicating effects of Fe and Mn, they have no linear relationships with toxic metals. Interestingly, the metabolic abundance of bacterial communities showed good correlations with different TMs in the sediment. These results highlight bacterial community characteristics as effective biomarkers for assessing TM pollution and practical tools for managing pollution control in coastal environment.

Interfacial interactions between colloidal polystyrene microplastics and Cu in aqueous solution and saturated porous media: Model fitting and mechanism analysis

Microplastic (MP) and heavy metal pollution have received much attention. Few researches have been carried out on the influence of the interaction between MPs and heavy metals on their transport in saturated porous media, which concerns their fate. Therefore, the interaction mechanisms between colloidal polystyrene microplastics (PSMPs) and Cu were first carried out by applying batch adsorption experiments. Subsequently, the transport and retention of PSMPs and Cu in saturated porous media was explored through column experiments. The interaction process between PSMPs and Cu was further investigated using density functional theory (DFT) calculations. Findings demonstrated that PSMPs had strong adsorption capacity for Cu ((60.07 ± 2.57) mg g-1 at pH 7 and ionic strength 0 M) and the adsorption process was chemically dominated, non-uniform, and endothermic. The O-containing functional groups on PSMP surfaces showed essential roles in Cu adsorption, and the adsorption process mainly contained electrostatic and complexation interactions. In column experiments, Cu could inhibit PSMP transport by the cation bridging effect and changing the electrical properties of glass beads, while PSMPs may facilitate Cu transport through the carrying effect. These findings confirmed that interfacial interactions between MPs and Cu could influence their transport in saturated porous media directly, providing great environmental significance.

Between Life and Death: Sea Urchin Embryos Undergo Peculiar DNA Fragmentation after Exposure to Vanadium, Cadmium, Gadolinium, and Selenium

Exogenous DNA damage represents one of the most harmful outcomes produced by environmental, physical, or chemical agents. Here, a comparative analysis of DNA fragmentation was carried out on Paracentrotus lividus sea urchin embryos exposed to four common pollutants of the marine environment: vanadium, cadmium, gadolinium and selenium. Using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, fragmented DNA was quantified and localized in apoptotic cells mapping whole-mount embryos. This is the first study reporting how different chemicals are able to activate distinctive apoptotic features in sea urchin embryos, categorized as follows: (i) cell-selective apoptosis, showing DNA fragmentation restricted to a subset of extremely damaged cells, acting as an embryo survival mechanism; or (ii) total apoptosis, with fragmented DNA widespread throughout the cells of the entire embryo, leading to its death. Also, this is the first report of the effects of Se exposure on P. lividus sea urchin embryos. These data confirm the TUNEL assay as the most suitable test to study DNA fragmentation in the sea urchin embryo model system. Taken together, this research highlights embryos' ability to find alternative pathways and set physiological limits for development under stress conditions.

First assessment of trace metals in the intertidal zone of the world's longest continuous beach, Cox's Bazar, Bangladesh

This study aimed to assess the concentrations of eight trace metals - Cr, As, Pb, Mn, Ni, Zn, Hg, and Co - in the intertidal zone of Cox's Bazar of Bangladesh, the world's longest continuous beach. Most metal concentrations were below sediment quality guidelines and other comparative studies. The mean metal concentrations (mg kg-1) were as follows: Mn (471.67) > Zn (256.35) > Cr (89.96) > Pb (39.66) > Ni (36.44) > As (18.79) > Co (11.08) > Hg (0.0036). Statistical analyses revealed that only samples collected from stations 5 and 7 presented any cause for concern. Risk assessment indices, i.e., Geo-accumulation Index (Igeo), Contamination Factor (CF), Pollution Load Index (PLI), Potential Ecological Risk Index (PERI), and Toxic Risk Index (TRI), all indicated a low to moderate risk of pollution for all sites, suggesting that the study area is currently free from any significant negative impacts resulting from human activities. The calculated Hazard Index (HI) was <1, indicating no significant non-carcinogenic impact on adults or children. The Total Carcinogenic Risk was also well below the threshold value.

Assessing the ecological and health risks associated with heavy metal pollution levels in sediments of Big Giftun and Abu Minqar Islands, East Hurghada, Red Sea, Egypt

This study assessed pollution levels, ecological and health risk, and spatial distribution of eight heavy metals in sediments of Big Giftun and Abu Minqar Islands, Red Sea, Egypt. Iron (Fe) and manganese (Mn) had the highest contents in both island sediments, while cobalt (Co) in Big Giftun and cadmium (Cd) in Abu Mingar had the lowest values. The obtained PCA data exhibited positively significant loadings of Cd, Co, copper (Cu), nickel (Ni), and zinc (Zn) with 51.03 % of data variance in Big Giftun, and lead (Pb), Cu, Mn, Ni, Zn, and Fe (37.7 %) in Abu Minqar sediments. The contamination factor (CF) showed low contamination for all metals, except cadmium; Cd (moderate). The geo-accumulation index (Igeo) values showed uncontaminated (Cd, Co), moderately (Cu), extremely contaminated (Fe, Mn) (Igeo > 5) in Big Giftun, and uncontaminated (Cd), moderately to strongly contaminated (Cu, Ni), and extremely contaminated (Fe, Mn, and Zn) in Abu Minqar sediments. The pollution load index (PLI) values indicated baseline level of contamination (PLI <1), and degree of contamination (DC) indicated low degree of contamination (DC < n) in all sediments. Nemerow pollution index (NPI) showed unpolluted sediments in Abu Minqar (NPI ≤1) and slight pollution (1 < NPI ≤2) in Big Giftun. Cd showed moderate potential ecological risk (40 ≤ Eri < 80) in Big Giftun sediments. Potential ecological risk index (PERI) indicated low risk sediments (PERI <150). Mean effects range median quotient (MERMQ) indicated low-priority risk of toxicity (MERMQ ≤0.1), and toxic risk index (TRI) showed no toxic risk in all sediments (TRI <5). The modified hazard quotient (mHQ) indicated very low severity of contamination (mHQ <0.5). The hazard quotient (HQ) levels of all metals were below the safe value (HQ <1). The hazard index (HI) levels indicated that no chronic risks occur (HI <1). The total cancer risk (TCR) for all metals were below the safe level (1 × 10-4) of the United States Environmental Protection Agency (U.S. EPA) guidelines.

Assessment of contamination of marine sediments and their potential toxicity in the Uglovoy Bay, Peter the Great Gulf, Sea of Japan/East Sea

The content of harmful heavy metals in the bottom sediments of the Uglovoy Bay (Peter the Great Gulf, Sea of Japan/East Sea) was studied based on the surveys carried out in 2016-2021. The contamination of the sediments in the bay was compared to the background concentrations of elements and to common contamination indices. The degree of contamination was calculated using the contamination factor (C_f), modified overall degree of contamination (mC_d), and index of geoaccumulation (I_geo). The toxicity of marine sediment samples for each metal was evaluated using the threshold effect level/probable effect level (TEL/PEL) values and the sediment quality guideline quotient (SQG-Q). The sources of pollutants entering the studied water area were analyzed. It is shown that the contamination of the Uglovoy Bay occurs continuously as a result of economic activities on its coast. The dynamics of contamination of the bay for the period 2016-2021 is presented.

Assessment of potential health risks from heavy metal pollution of surface water for drinking in a multi-industry area in Mali using a multi-indices approach

The Niger River, Bamako's population's primary drinking water source, is threatened by human activities. This study examines the Niger River pollution trend using heavy metals pollution indexes and Bamako's population's non-carcinogenic and carcinogenic related health risks. Parameters were monitored at fifteen sampling locations in low and high flow seasons. pH (7.30-7.50) and fluoride (0.15-0.26 mg/L) were within the normal drinking water range. Among seven heavy metals (copper, zinc, cadmium, nickel, iron, manganese, and lead), the latter three were above the drinking water standard. The degree of contamination was negative, pointing to better water quality. However, the heavy metal evaluation index (HEI) was below the mean (5.88), between the mean and twice the mean, indicating a low and medium degree of pollution. Besides, heavy metal pollution indexes (HPI) were above the standard value (100), explaining a low-medium pollution level. High values of HPI could be explained by the industrial units' intensive activities coupled with the runoff effect. The hazard index (HI) indicated a low and medium non-carcinogenic health risk for adults and children. The probability of cancer risk (PCR) of nickel showed a cancer risk. Therefore, the river was polluted with trace elements and could not be used for drinking water without any treatment.

Metals profile in deep-sea sediment from an active tectonic region around Simeulue Island, Aceh, Indonesia

Simeulue waters are adjacent to the northern part of Sumatra Island, which is undergoing massive land-use transformations; moreover, the waters are located in an active tectonic region. Land changes and tectonic activity might affect the metal pollution profile in this deep sea area. Thus, this study aimed to investigate the vertical profile and assess the sediment quality from the deep-sea marine sediment around Simeulue Island based on metal concentration. Seventy-six bottom sediment samples were collected from eight cores at a water depth of up to 2800 m in the Simeulue waters, Indonesia, in November 2017. Metals Cd, Cu, Fe, Ni, Pb, and Zn were quantified from the cores and multivariate analyses were carried out to understand the process. Metals distributions are analogous to the grain size parameters and LOI₅₅₀ distribution pattern, while Sumatra and Simeulue islands influenced grain size and LOI₅₅₀ spatial distribution. The vertical grain size profile exhibited no extreme oscillation in the investigated cores. Thus, sediment transport from the Island was the main suspect for these metals' profiles in the deep water, and the tectonic activity had a minor impact. Cu, Ni, Pb, and Zn tend to rise in the collected cores, suggesting that the accumulation of the metals is growing. While Fe tended to be stable and Cd oscillated in the cores. Indices were computed to assess the metal contamination profile. The cores were dominated by EF class 1 (none to slight enrichment) status and I_geo class 1 (unpolluted). Cd was the metal of concern in the study since a high Cd was observed in some layers (maximum EF = 26.45 and maximum I_geo = 3.81). Thus, this study can be used as a database to improve the regulation formulation for improved environmental managerial efforts in the region.