Over the past decades, the growth in human population and economic activities has led to an increase in maritime traffic. This rise puts additional pressure on marine environments, vessel fuel spills being considered to have a major impact on the ecosystem. In this study we conducted the micronucleus (MN) test on 48 limpets of the genus Patella between June and July 2024, from four marinas of the Asturias coast (SW Bay of Biscay) with different traffic volumes, water metal contents (As, Cd, Hg and Pb), and use of fuel types as determined from a survey to ship owners. We also conducted an experiment exposing limpets to recreational boat contaminants (petrol, diesel, and ecological soap) for 5 days, then analyzing MN and other nuclear abnormalities (NAs). Results revealed that limpets exposed to petrol exhibited the highest MN count, and the highest proportion of MN (over all the NA), followed by those exposed to diesel. The group treated with ecological soap did not differ significantly from the untreated control. Limpets from the biggest Gijón marina exhibited the highest MN count and the highest As concentration. In regression analysis, the level of MN and other NAs in limpets sampled from the marinas was explained directly by the city size, and by the sum of stressors including the proportion of boats using petrol. The proportion of MN over total abnormalities was correlated with the number of moorings. These results support the contribution of recreational boating to cytogenotoxicity in local communities of marine fauna, likely from fuel spills.

Industrial activities along riverine environments in the Niger Delta have raised serious concerns about heavy metal contamination of surface water and sediments, with potential implications for ecosystem integrity and public health. The Okulu River in Eleme Local Government Area, Rivers State, is increasingly exposed to industrial effluents, making it necessary to assess its environmental quality. The study employed an environmental analytical research design to assess heavy metal concentrations in surface water and sediments of the Okulu River in Eleme Local Government Area, Rivers State, Nigeria. Five sampling points, including four industrially impacted sites and one control, were analyzed. Surface water and sediment samples were collected, digested using mixed acids, and analyzed for Fe, Pb, Cu and Cr using Atomic Absorption Spectrophotometry. Results were statistically analyzed and compared with World Health Organization standards to evaluate contamination levels and potential environmental and health risks. The results revealed spatial variations in heavy metal concentrations in surface water and sediments of the Okulu River. Iron levels in surface water (1.401–10.46 mg/L) and sediments (1.4565–10.581 mg/L) were below the WHO limit (20 mg/L). Lead concentrations in surface water (0.029–14.91 mg/L) exceeded the WHO limit (0.01 mg/L), indicating contamination, while sediment lead levels (0.0359–36.233 mg/L) remained within the permissible limit (400 mg/L). Copper concentrations in surface water (0.002–3.814 mg/L) and sediments (0.3432–18.754 mg/L) were below WHO limits (35 mg/L). Chromium showed elevated levels in surface water (0.397–24.09 mg/L) and sediments (0.01523–15.1506 mg/L), exceeding WHO limits (0.003 mg/L). The study concludes that while some metals pose minimal risk, elevated lead and chromium levels preasent potential environmental and health concerns, underscoring the need for continuous monitoring and effective regulation of industrial discharges into the Okulu River.

Metals in water used by artisanal and small-scale gold miners for gold-mercury amalgamation in Western Kenya.

Mining liabilities as a source of toxic metals and physicochemical contaminants in tropical rivers.

Metal enrichment in the tropical estuarine environment and associated health risk assessment using PMF and Monte Carlo simulation.

The levels of heavy metal in marine environment and fish are very crucial for the assessment of heavy metal contamination which poses deleterious effect towards communities, especially those in Petagas River. Four randomly caught fish species (Sagor Catfish, Indo-Pacific Tarpon, Spotted Catfish and Nile Tilapia) from the river were dissected to obtain the fish flesh and prepared by following the Protocol of Perkin Elmer Pure Atomic Spectroscopy Standard (2001). The water sample and fish flesh sample were analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to identify the heavy metal concentration that affect the level of metal contaminants. The highest average of heavy metal concentration was found in Potassium (K) 10.04 µg/L, followed by Arsenic (As) 0.46 µg/L and Lead (Pb) 0.63 µg/L in the water sample. For fish sample the highest average concentration of heavy metal was found in Potassium (K) 14.28 µg/g, followed by Arsenic (As) 1.33 µg/g and Lead (Pb) 1.14 µg/g. The result obtained from ICP-MS was compared with the guidelines that have been set by the Malaysian Food Act (1983) and Regulation (1985), Malaysian Interim Water Quality Standard (NWQS) (2008), World Health Organization (WHO) and the Food and Agriculture Organization (FAO). The present study demonstrates rather high heavy metal concentration in water for As and Pb that exceeded the permissible limit set by NWQS (2008) (0.05 mg/L) and (0.01 mg/L) and FAO/WHO (2017) (0.01 mg/L) and (0.01 mg/L) respectively. However, the K concentration did not exceed the permissible limit set by FAO/WHO (2017) (12.0 mg/L) and no data published for K in NWQS (2008). The present study for heavy metal concentration for As and K elements in fish sample were found to exceed the permissible limit set by MFAR (1983 & 1985) (1.0 µg/g) and (no limit published for K) and FAO/WHO (1984) (0.1 µg/g) and (1.6 – 2.0 µg/g) respectively. The Pb concentration in fish sample did not exceed the permissible limit set by MFAR (1983 & 1985) but it exceeded the permissible limit set by FAO/WHO (1984) (0.2 µg/g).

The availability of clean water is still a serious challenge, especially in rural areas and developing areas. This study aims to examine the innovation of natural-based water purification technology through the use of avocado seed peel as a natural coagulant combined with Solar Water Disinfection (SODIS). The method used is a literature review by analyzing scientific articles in the last ten years related to the effectiveness of avocado seed shells and SODIS in water treatment. The results of the study show that avocado seed shells contain bioactive compounds such as tannins, flavonoids, and polyphenols that function as coagulation and adsorption agents, so that they are able to reduce turbidity, color, and organic and heavy metal content in water. Meanwhile, SODIS technology has been proven to be effective in reducing microbiological contamination, particularly pathogenic bacteria, through the mechanism of UV-A radiation and temperature increase. The combination of these two methods has been proven to complement each other, where pre-treatment with avocado seed peel reduces the turbidity of water so that the penetration of UV rays in the SODIS process is more optimal. The integration of simple, cheap, and environmentally friendly methods has great potential to be applied as an alternative to sustainable clean water supply while supporting the achievement of the Sustainable Development Goals (SDGs) related to clean water and sanitation.

This study investigated the distribution of aluminum (Al), arsenic (As), and lead (Pb) in water, sediments, and two dominant aquatic plants—morning glory (Ipomoea aquatica) and water mimosa (Neptunia oleracea)—from the middle part of Songkhla Lagoon. Heavy metal concentrations in water and sediments were below national and international standards, indicating low contamination risk. Both concentrations of As and Pb in sediment had severe enrichment (EF > 15) at all stations, suggesting anthropogenic inputs. In contrast, geo-accumulation index (Igeo) values were negative, indicating unpolluted sediments and showing two-index differential sensitivity. In aquatic plants, heavy metals were mainly accumulated in roots, with significantly lower concentrations found in stems and leaves, especially for As and Pb. Morning glory showed greater root uptake of As and Pb than water mimosa, making it a better candidate for bioindication. Despite root accumulation, translocation factors (TF) and bioaccumulation factors (BAF) were closed to zero for all stations and metals, confirming that metals did not effectively move into edible aerial tissues. This pathway from sediment to root, but not to leaf or stem, suggested that the edible parts of these plants remain relatively safe for consumption under current conditions. Low contamination levels in water and sediment limited metal transfer to upward plant parts, and environmental parameters (e.g., sediment pH, organic carbon, and particle size) supporting these species, particularly morning glory for rhizo-filtration and safe, sustainable use in brackish aquatic environments.

The ship recycling industry in Bangladesh has transformed from informal, beaching-based operations into a globally significant sector, representing over 45% of global recycling tonnage and providing essential raw materials and employment opportunities. This study adopts a mixed-methods design, combining secondary data analysis (2014–2024 gross tonnage records), over 500 stakeholder interviews, and ARIMA-based scenario forecasting up to 2050. The findings indicate that the sector contributes approximately USD 2.1 billion annually to the national economy and supports more than 250,000 direct and indirect jobs. Despite its economic significance, major compliance gaps persist with the Hong Kong International Convention (HKC): only about 52% of yards are certified or in the process of certification. Workplace accident rates remain roughly 30% higher than regional averages, while environmental assessments reveal elevated heavy metal concentrations in soil and water, underscoring weak regulatory enforcement and environmental management. Comparative analysis shows that India has successfully modernized over 120 HKC-compliant yards through targeted policy and financial incentives, whereas Pakistan is rapidly upgrading its Gadani facilities through major investment programs. Forecasting results identify three trajectories: a baseline of ~2.7 million GT annually to 2050, an optimistic expansion to ~5 million GT with green reforms, and a pessimistic decline below 2 million GT if progress stagnates. To ensure sustainable advancement, five strategic policy pillars are proposed, offering an evidence-based roadmap for Bangladesh to achieve safe, environmentally sound, and globally competitive ship recycling.

This research was carried out to assess the impacts of anthropogenic activities on heavy metal concentrations in water and sediments in Eniong River, Nigeria. The study was carried out for a period of twelve months, covering both the wet and dry seasons. Water and sediment samples were analyzed to determine the concentration of selected heavy metals such as Cd, Cu, Cr Fe, Pb, and Zn. The analysis was done using an atomic absorption spectrophotometer. The result revealed variation in the concentration of all heavy metals across the sampling locations. The concentrations ranged from 0.00 – 0.15 mg/L and 0.01- 11.75mg/kg for water and sediment samples, respectively. Concentrations of some metals were higher in due to tremendous anthropogenic activities. Comparatively, concentrations were higher in sediment samples 11.75mg/kg than in water samples 0.15 mg/L, which could be attributed to desorption of the metals from water onto the sediment beneath the water. The results also revealed that some metals, such as Copper (0.15 mg/L) and Iron (0.15 mg/L) were higher in water than in sediment. Generally, highest concentration of 11.75mg/kg for chromium was recorded in sediment samples compared to other heavy metals. Concentration of the metals followed the pattern shown: Cu > Fe > Cr > Zn > Pb > Cd for water samples and Cr > Cu > Fe > Zn > Pb > Cd for sediment. It could be concluded that the highest concentration of the metals in water and sediment samples were 0.15mg/l and 0.15mg/kg respectively and were recorded in the location of tremendous anthropogenic activities, reflecting a corresponding higher impact on the metals. This suggests the need for routine monitoring to prevent escalation.

The objective of this paper is to investigate heavy metal concentrations in surface water from three stations (upstream, midstream, and downstream) and in five commonly consumed fish species (Oreochromis niloticus, Clarias gariepinus, Synodontis schall, Tilapia zillii, and Schilbe mystus) from the Komadugu-Yobe River at Gashua, northeastern Nigeria using appropriate standard methods after acid digestions. Results showed that Pb (0.18–0.28 mg/L) and Cd (0.05–0.08 mg/L) in water, and Pb (1.10–1.78 mg/kg) and Cd (0.18–0.25 mg/kg) in fish exceeded WHO/FAO permissible limits. Bioaccumulation was highest in C. gariepinus and S. mystus. These findings indicate moderate-to-high ecological stress and food safety concerns. Continuous monitoring, pollution control, and public awareness are strongly recommended.

The Lower Passaic River (LPR), located within the New York/New Jersey Harbor Estuarine System, has experienced long-term industrial activities, resulting in elevated concentrations of trace metals in sediment and water. This study aims to assess the bioaccumulation behavior, potential human health risks, and sources of copper (Cu), lead (Pb), and mercury (Hg) in the LPR. Trace metal concentrations were measured in water, sediment, and seven edible aquatic species. Data were analyzed using statistical approaches, and evaluated by bioaccumulation factors (BAFs) and human health risk assessments based on U.S. Environmental Protection Agency (USEPA) guidelines. Results showed that Hg exhibited the highest bioaccumulation potential among the studied metals, except for Cu in Callinectes sapidus. Non-carcinogenic risks from the consumption of aquatic species followed the order Cu > Hg > Pb, with total target hazard quotient (TTHQ) values below 1, suggesting the non-carcinogenic health risk is negligible for adults and for most species in children, except C. sapidus and Morone americana. Carcinogenic risks for all species were within the acceptable threshold (Target Risk < 1 × 10−4). Sensitivity analysis indicated that body weight and exposure duration primarily influenced children’s carcinogenic risk, whereas trace metal concentrations were more significant for adults. Overall, this study provides insight into contaminant dynamics and health implications in a legacy-contaminated urban river system.

Seasonal and spatial variations in water quality, heavy metal concentration in water, sediment and bioaccumulation in Pseudotolithus species from the Gulf of Guinea, Ondo state, Nigeria

This study aimed to analyze the concentrations of manganese (Mn) and iron (Fe) in both water and sediment samples from the Sanga-Sanga River, Kutai Kartanegara Regency, East Kalimantan Province. The research was conducted from October to December 2024 at three stations representing the upstream, midstream, and downstream sections of the river. Sampling was performed using a purposive method based on site characteristics, and analyses were carried out both in situ and at the Water Quality Laboratory, Faculty of Fisheries and Marine Science, Mulawarman University. The concentrations of Mn and Fe were compared with the Indonesian river water quality standard (Government Regulation No. 22 of 2021) and sediment quality guidelines established by the Australian and New Zealand Environment and Conservation Council (ANZECC, 2000). The results showed that Mn concentrations in river water ranged from 0.325 to 1.181 mg/L, exceeding the permissible limit of 0.1 mg/L, while Fe concentrations ranged from 0.3475 to 0.468 mg/L, surpassing the standard of 0.3 mg/L. In sediments, Mn concentrations ranged from 42.38 to 964.47 mg/kg and Fe concentrations from 11,341.23 to 50,344.72 mg/kg, with several stations exceeding the ANZECC guideline limits. Higher concentrations were generally found at midstream and downstream stations, particularly in areas influenced by coal mining, barge transport, and ship repair activities. These findings indicate that the Sanga-Sanga River has experienced notable contamination by Mn and Fe, primarily due to anthropogenic activities related to coal industry operations. Continuous monitoring, stricter waste management, and the implementation of pollution control measures are recommended to prevent further environmental degradation and protect aquatic ecosystems.

This study aimed to investigate how exposure to elevated water temperature and metal concentration jointly affect the physiology of Amazonian fish. Aboard a research vessel in the Amazon, we evaluated the effects of water temperature (river T°C at 31.5°C and a + 4°C increase to 35.5°C) and of 3-h copper (Cu) exposure (up to 600 μg/L) in juvenile Tambaqui (Colossoma macropomum) exposed in freshly collected Rio Negro ('black water') and Rio Solimões ('white water') waters. In Cu-free water, the +4°C raise accelerated physiological Na+ influx and efflux rates, but only in Rio Negro water. Temperature had no effects on the other physiological fluxes (Cl-, K+ and ammonia fluxes). Cu exposure led to net losses of Na+ (via increased efflux), Cl- and K+ and decrease in acute upper thermal tolerance (CTmax). These Cu effects were more prominent in Rio Negro water, where Cu bioavailability was the greatest. The +4°C change had no effect on gill Cu accumulation and, overall, there was limited evidence that warming worsened Cu-induced ionoregulatory disturbances. However, in Rio Negro, as Cu and heat both separately promoted Na+ net losses, fish Na+ balance was the most compromised in the presence of the two stressors. Altogether, the impaired thermotolerance and ionoregulation under combined Cu and heat exposures suggest a cumulative physiological interaction between two stressors that are increasing threats to the Amazon basin.

Current drinking water grab sampling is insufficient for monitoring metals that have location-dependent or temporally variable concentrations. This study evaluated the potential of three widely used residential POU filters to serve as volume-integrated monitoring devices for multiple metals. We investigated the two criteria for metals to be monitored by POU filters of (1) complete removal and (2) subsequent complete extraction. To assess the first criterion, lead, hexavalent chromium, arsenate, copper, manganese, and zinc were loaded onto filters both separately using lab-prepared water and together using spiked St. Louis tap water. While cationic metals were robustly retained on the filter media (72-100%), hexavalent chromium and arsenate had lower removal extents (11-62%). To examine the second criterion, metals that had accumulated on the filter media were extracted for quantitative analysis. Extraction methods completely recovered the accumulated metals (87-110%). Volume-averaged concentrations of metals in the incoming water could be quantified based on the mass of metals extracted and information about the cumulative volume of water processed. We demonstrated that POU filters can be used as multipurpose tools to both remove multiple metals from drinking water and monitor incoming water quality over the duration of filter use.

Urban landscapes play a critical role in shaping air and water quality, influencing the distribution of heavy metals and other pollutants. This study investigates the spatial and temporal variations of heavy metal concentrations in urban snow water within Jelgava City, Latvia, over three winter seasons (2017–2019). The study examines the relationships between heavy metal accumulation and urban land use categories, including residential, natural, transport, apartment, public, and industrial zones. Snow samples were analyzed for lead (Pb), nickel (Ni), chromium (Cr), and vanadium (V) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), with statistical analyses performed to determine pollution trends and influencing factors. Results revealed significant spatial and temporal variations in heavy metal concentrations, with Pb exhibiting the highest mean concentration of 7.07 µg/L, followed by Ni (1.93 µg/L), Cr (2.77 µg/L), and V (2.08 µg/L). Maximum recorded values reached 72.26 µg/L for Pb, 40.75 µg/L for Ni, 71.35 µg/L for Cr, and 64.16 µg/L for V, highlighting extreme pollution events. Statistical analysis confirmed significant year-to-year variations for Pb (p = 0.0047), Ni (p = 0.00028), and Cr (p = 0.00030), whereas V remained relatively stable (p = 0.0696), suggesting a continuous pollution source. The study also highlights the influence of urban density on heavy metal accumulation, emphasizing the impact of vehicular emissions, heating systems, and industrial activities. The findings underscore the need for integrated urban planning strategies to mitigate heavy metal pollution and improve environmental quality in urban settings.

Despite increasing interest in the environmental legacies of artisanal and small-scale gold mining (ASGM), the health implications associated with the consumption of crops cultivated on abandoned, naturally revegetated mine sites (ANRGS) in Ghana remain critically under-researched. In response to this gap, the present study comprehensively assesses heavy metal contamination in cucumber, soil, and pit water sampled from a six-year-old abandoned, naturally revegetated illegal mining site (ANRGS). Human health risk assessments were conducted rigorously using standard models for Chronic Daily Intake (CDI), Hazard Quotient (HQ), Hazard Index (HI), and Incremental Lifetime Cancer Risk (ILCR). Heavy metal concentrations in soil, pit water, and cucumber were measured using standard acid digestion and analysed with Inductively Coupled Plasma Mass Spectrometry (ICP-MS, Nexion 2000, PerkinElmer), along with a Palintest multi-meter for water quality parameters, following validated protocols. The results revealed that cucumber fruits produced from the ANRGS were contaminated with high levels of Hg, Cd, Cu, As, and Pb, which exceeded the USEPA reference doses. Soil samples recorded concentrations of Hg (28.61 mg/kg), Cd (44.19 mg/kg), Pb (25.91 mg/kg), Fe (2073.1 mg/kg), As (30.08 mg/kg), and Cu (286.55 mg/kg), all above recommended soil guidelines. Although pit water met WHO physical standards, it was significantly contaminated with Cu, Cd, and As, surpassing WHO limits for drinking and irrigation. The health risk analysis indicated both noncarcinogenic and carcinogenic risks for children and adults through cucumber and pit water consumption. The Hazard Index (HI) ranged from 0.447 to 380 for children and 0.13–173 for adults, associated with cancer risks due to elevated As, Cd, and Pb levels. Children were more vulnerable to both health risks than adults. The study concludes that cucumbers grown on ANRGS at Ajamesu pose significant health risks and are unfit for consumption.

Environmental contaminants from mining activities are becoming problematic in the developing world, necessitating greater attention to their fate and transportation. In particular, gold mining activities that utilize strong lixiviants may result in heavy metal dissolution and distribution to environmental compartments. This study aimed to determine the status of some selected heavy metals in stream water, sediment and agricultural soil near a large-scale cyanidation gold mining operation, Laga Dambi. Ethiopia. The stream water, sediment and soil samples were digested under optimal digestion conditions. Inductively coupled plasma-optical emission spectrometer was used to determine the concentrations of Zn, Mn, Cu, Fe, Sn, Co, Ni, Cr, Pb, Cd, As, and Hg in samples collected from potentially contaminated sites associated with the Laga Dambi gold mine and control sites. The mine is notable because it is disposed of tailings in an impoundment created in a stream zone, where the stream flows over the tailings facility before exiting the mine site. The mean concentrations of the heavy metals in stream water and sediment were generally higher than the recommended levels reported by international agencies. The mean concentrations of Sn, Cr, Cd, and Hg were also high in agricultural soil that received irrigation water from the mine down gradient rivers. In general, stream water, sediment and agricultural soils were found to contain high concentrations of heavy metals, particularly Hg and As, which are typically associated with gold mining. The findings show that the heavy metal concentrations of stream water, stream bank sediment, and agricultural soil were high, indicating an increased risk for community exposure during consumption under the current conditions. On the basis of these findings, we strongly recommend strict monitoring and regulatory control of the study area to protect the environment and health of exposed populations.

The study assessed Heavy Metal concentrations of surface water of River Gongola, Gombe State, Nigeria in four (4) stations. The sampled water were digested and analyzed for heavy metals using AAS model 205. Cu (0.036, 0.032, 0.035, 0.039) Pb (0.006, 0.001, 0.004, 0.003), Cr (0.033, 0.034, 0.045, 0.021), Fe (0.026, 0.028, 0.017, 0.027) and Zn (0.963, 0.535. 0.878, 0.333) in all the stations were below the WHO/NSDWQ limit. Cd (0.011, 0.013, 0.006), As (0.030, 0.033, 0.024), Ni (0.095, 0.099, 0.091) in Stations 1, 2 and 4 and Mn (0.471) in Station 2 were higher than the limit. Analysis of Variance revealed that there were significant differences (P<0.05) with months for all the metals but no difference across stations except for Zn. Tukey Post Hoc Test revealed that stations 1 and 3 which were not significantly different from each other, varied significantly with stations 2 and 4. Heavy Metal Pollution (HPI) calculation revealed that all the stations had HPI values >100 (253.13, 295.92, 105.52 and 103.52) for stations 1, 2, 3 and 4 respectively. And these are above the threshold of 100. Cd concentrations contributed significantly to the high HPI values in all stations. However, station 2 had the highest value followed by 1. This result shows that the water from this river is contaminated with respect to Cd, As and Ni.