High Ecological Risk Research Articles

Non-target and target screening and risk assessment of per- and polyfluoroalkyl substances in textile wastewater and receiving river

Textile industry uses varieties of chemicals including per- and polyfluoroalkyl substances (PFAS). PFAS are known to be persistent and incompletely removed in wastewater treatment plants (WWTPs). So far, little is known about what types of PFAS are used in the textile industry and their potential risks. Here we investigated PFAS in two WWTPs and a receiving river of a textile industrial park in Guangxi, China, by using both target and non-target analyses over a two-year period. The target analysis identified 11 specific PFAS, while the non-target analysis revealed a list of 648 different PFAS, including both legacy and emerging substances. Notably, perfluorooctanoic acid (PFOA) was still the most prevalent compound detected. Of particular concern was the finding that the investigated WWTPs, which employs an A/O (Anaerobic/Aerobic) process, exhibited a poor removal efficiency for PFAS. The average removal rate was only 22.0 %, indicating that the current treatment processes are inadequate in effectively mitigating PFAS contamination. Correlation analysis further highlighted the potential for PFAS to be transported from WWTPs to the receiving river, revealing a significant and strong positive correlation between the PFAS in the WWTP effluent and those of the river. Perfluorooctanesulfonic acid (PFOS) and two emerging PFAS (DTXSID30240816 and DTXSID90240817) were identified to have high ecological risks in the receiving river. Notably, these two emerging PFAS are homologues, and their presence in WWTPs has been poorly reported. The findings highlight the wide use and persistence of PFAS in current textile WWTPs, indicating potential long term risks to the receiving environment.

Assessment of ecological and health risk impact of heavy metals contamination in stream sediments in Itapaji-Ekiti, SW Nigeria

BackgroundHeavy metal contamination in aquatic ecosystems is a major environmental and health concern globally. This study assessed the ecological and health risks associated with heavy metal pollution in stream sediments in Itapaji-Ekiti, Southwest Nigeria. The study contributes collectively to a comprehensive understanding of the geochemical dynamics and contamination factors affecting the studied stream sediments. MethodsHeavy metals study was conducted on stream sediments within the geographical confines of sheet 244, Ado map. Seventeen stream sediment samples were obtained from various sites and subjected to analysis to determine the concentrations of heavy metals such as lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), barium (Ba), arsenic (As), nickel (Ni) and vanadium (V) using X-ray Fluorescence (XRF). The results showed that the concentrations of these metals exceeded permissible levels at most sampling sites, indicating significant contamination of the stream sediments. The concentrations and pollution levels of the heavy metals from selected sampling sites were documented for ecological and health risk evaluations. ResultThe findings revealed that the concentrations of these metals surpassed acceptable thresholds at the majority of sampling locations, indicating significant contamination of the stream sediments. The concentrations of heavy metals, specifically Cr and Cd, exhibit moderate contamination, while Pb and Ba demonstrates a significant contamination factor with moderate to extreme degree of contamination. Several ecological risk indices were calculated to evaluate the potential ecological risks. The results revealed that the stream sediments posed considerable to very high ecological risks at most sites based on the risk quotient, contamination factor and pollution load index. The non-carcinogenic and carcinogenic risk assessments for heavy metals in stream sediments exposed potential health risks, especially for children, indicating the need for protective measures. The cumulative cancer risk, particularly for adults, raised concerns about the overall health implications of prolonged exposure to the heavy metal concentrations in the streams. ConclusionThe study also evaluated ecological and health risks, revealing potential risks from heavy metals. Hazard and cancer risk assessments suggested the increasing potential of heavy metals to pose health risks, particularly for inhabitants of the area.

Pollution Analysis of an Active River Bottom Sediment in Borokiri (Ikpukulu River), Niger Delta, Nigeria

The Niger Delta region, endowed with significant oil and gas resources, faces environmental challenges linked to artisanal petroleum refining activities. This study explores the environmental repercussions of these activities on the ecosystem health of Ikpukulu River bottom sediments in Borokiri, Niger Delta, Nigeria. The study incorporates an assessment of heavy metal and hydrocarbon contamination using geoaccumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (PERI). Three sampling points (X, Y, and Z) along the Ikpukulu River were investigated. While heavy metal concentrations generally fell within background levels, hydrocarbon content, particularly Total Hydrocarbons (THC), exhibited significant pollution. The PERI values for all three points indicated very high ecological risk, demanding immediate attention and remediation efforts. The Ikpukulu River serves as a potential sink for waste from illegal hydrocarbon refining, highlighting severe coastal river pollution in the region. Proactive measures and stringent pollution control regulations are recommended to safeguard the ecosystem's health. The study contributes valuable insights for remediation efforts and policy development in addressing the environmental challenges associated with artisanal petroleum refining in the Niger Delta.

Machine learning-based models to predict aquatic ecological risk for engineered nanoparticles: using hazard concentration for 5% of species as an endpoint.

Assessment and prediction for the ecotoxicity of engineered nanoparticles (ENPs) at the community or ecosystem levels represents a critical step toward a comprehensive understanding of the ecological risks of ENPs. Current studies on predicting the ecotoxicity of ENPs primarily focus on the cellular and individual levels, with limited exploration at the community or ecosystem levels. Herein, we present the first of the reports for the direct prediction of aquatic ecological risk for ENPs at the community level using machine learning (ML) approaches in the field of computational toxicology. Specifically, we extensively collected the threshold concentrations of twelve ENPs including metal- and carbon-based nanoparticles for aquatic species, i.e., hazardous concentrations at which 5% of species are harmed (HC5), established by a species sensitivity distribution. Afterwards, we used eight supervised ML methods including Adaboost, artificial neural network, C4.5 decision tree, K-nearest neighbor, logistic regression, Naive Bayes, random forest, and support vector machine to develop nine classification models and four regression models, respectively, for the qualitative and quantitative prediction of HC5. The evaluation of model performance yielded the internal validation accuracy of all classification models ranging from 71.4 to 100%, and the determination coefficient of regression models ranging from 0.702 to 0.999, indicating that the developed models showed good performance. By using a cross-validation method and an application domain characterization, the selected models were further validated to have powerful predictive ability. Furthermore, the incorporation of three nanostructural descriptors (metal oxide sublimation enthalpy, zeta potential, and specific surface area) linked to toxicity mechanisms (the release of metal ions, the stability of dispersions of particles in aqueous suspensions, and the surface properties of the material) effectively enhanced the prediction power and mechanistic interpretability of the selected models. These findings would not only be beneficial in the screening of ENPs with potential high ecological risks that need to be tested as a priority but also contribute to the development of environmental regulations and standards for ENPs.

Characterization of Metal Elements in Atmospheric PM2.5 and Health Risk Assessment in Heze in Winter from 2017 to 2018

Atmospheric PM2.5 samples were collected in Heze, Shandong Province, from a total of three sampling sites at Heze College, Huarun Pharmacy, and a wastewater treatment plant between October 15, 2017 and January 31, 2018, to determine the concentrations of 21 metal elements in PM2.5 using inductively coupled plasma mass spectrometry (ICP-MS). The degree of elemental enrichment was also discussed, the health risks and potential heavy metal ecological risks were assessed. The results showed that ρ (PM2.5) ranged from 26.7 to 284.1 μg·m-3 at the three sampling sites during the sampling period, and the concentration values did not differ significantly, all of which were at high pollution levels. The highest concentrations of K were found in the three sampling sites, accounting for 31.03%, 39.47%, and 38.43% of the total, respectively, mainly due to the high contribution of biomass burning in autumn and winter in Heze, a large agricultural city. The highest concentrations of Zn, 89.70, 84.21, and 67.68 ng·m-3, were found in the trace elements at the three sampling sites, respectively. The enrichment factor results showed that the enrichment factor values of Zn, Pb, Sn, Sb, Cd, and Se were higher than 100, among which the enrichment factors of Cd and Se were higher than 2 000 and 4 000, respectively, which were significantly influenced by anthropogenic activities and might have been related to industrial production, metal smelting, road sources, and coal combustion emissions. The health risk results showed that there was some potential non-carcinogenic risk (HQ>0.1 for children and adults) for As and a combined potential non-carcinogenic risk (HI>0.1) and some potential carcinogenic risk (CRT>1×10-6) for both children and adults at the three sampling sites. There was a more significant carcinogenic risk (CRT>1×10-4) for adults at the wastewater treatment plant, and the slightly higher carcinogenic risk for adults than that for children may have been related to the longer outdoor activity and higher PM2.5 exposure for adults. The elements with the highest potential ecological risk values were Cd, As, and Pb, with Cd exhibiting a very high potential ecological risk that should be taken seriously. All three sampling sites showed a very high combined potential ecological risk, with the intensity spatially expressed as Heze College>Huarun Pharmacy>wastewater treatment plant.

Potential Ecological Risk Assessment of Soil Heavy Metals in Fengdong New District Based on Information Diffution Model

The large-scale construction of new districts has led to severe soil heavy metal pollution. Therefore, taking Fengdong New District as the target research area, the descriptive statistics of heavy metal content characteristics and Kriging interpolation analysis have been conducted, and the potential ecological risk index and information diffusion theory were further combined to create an information diffusion model based on risk assessment. Finally, the pollution degree, ecological risk, and risk occurrence probability of Pb, Cu, Cd, and Hg were discussed. The findings revealed that the average concentrations of the four heavy metals far exceeded the background value of soil heavy metals by a factor of 1.943 (Pb), 1.419 (Cu), 3.074 (Cd), and 3.567 (Hg), respectively. Moreover, the distribution of soil heavy metals showed strong variability(CV>65%)owing to human interference. The distribution of Pb and Cu pollution were predominantly influenced by industrial production and land development for construction purposes, whereas industrial activities, agricultural practices, and transportation served as the primary sources of Cd contamination. On the other hand, industrial construction emerged as the major factor contributing to Hg pollution. The average values of individual potential ecological risk index for heavy metals of 9.716 (Pb), 7.095 (Cu), 92.292 (Cd), and 142.469 (Hg), coupled with the regional comprehensive potential ecological risk index (RI) average of 251.573, signified that the region was overall characterized by a relatively high potential ecological risk status. The overall potential ecological risk for Pb and Cu in the region were mild, whereas Cd and Hg posed moderate to high risks, indicating that Cd and Hg were the dominant driving factors behind regional heavy metal pollution. The evaluation results of the information diffusion model based on the potential ecological risk indicated that the probability ranking of different levels of comprehensive potential ecological risk was as follows:slightly high (38.98%) > moderate (38.55%) > high (5.89%) > slight (5.15%) > extremely high (3.56%). The exceeding probabilities of potential ecological risk levels for Cd and Hg were significantly higher than those for Pb and Cu. The exceeding probability of different pollution levels of Hg were slight (94.89%), moderate (66.85%), slightly high (23.62%), high (3.9%), and extremely high (2%), of which only the surpassing probability of the slight level was lower than that of Cd. The prediction error of pollution probability of each potential ecological risk level was less than 5%, demonstrating the reliability of the information diffusion model based on the risk assessment. This research will provide technical reference and support for the monitoring and management of potential ecological risks from soil heavy metals in limited sample data regions.

Ecological Risk Assessment of Forest Landscapes in Lushan National Nature Reserve in Jiangxi Province, China

It is highly valuable to analyze and assess the landscape ecological risk of nature reserves to prevent and resolve ecological risks, as well as to effectively protect and maintain the sustainable development of nature reserves. Taking the forest landscape of the Lushan National Nature Reserve as its study object, this study performed grid processing for the nature reserve and classified forest landscape types using the Forest Resource Inventory Database in 2019. A landscape ecological index model was constructed to evaluate the ecological risk. Global and local Moran index values were used to reveal the autocorrelations for ecological risk. The geodetector method was used to comprehensively analyze the effects of natural and human factors on ecological risk. The results showed that, in general, the ecological risk level of the nature reserve was relatively low, as the proportion of the lowest-, lower-, and medium-risk areas to the total forestry land area accounted for 91.03%. The ecological risk ranking of each functional zone, from high to low, was in the order of the experimental zone, the buffer zone, and the core zone. The ecological risk levels of different forest landscape types were closely related to their area, spatial distribution, and succession stage, as well as human factors, such as the proximity to roads and settlements, etc. The forest landscape with the highest ecological risk was the Cunninghamia lanceolata (Lamb.) Hook. forest, and the forest landscape with the lowest ecological risk was other forestry land. Ecological risk had a positive spatial correlation and tended to be aggregated in space, demonstrating coupling with the proximity to roads and settlements. The ecological risk was affected by both human and natural factors, among which human factors played a dominant role. The proximity to roads and settlements, the relative humidity, and the temperature were the main driving factors. The interaction of pairwise factors had a stronger influence than that of single factors. Therefore, controlling the intensity of human activities and enhancing the coordination between humans and nature are beneficial for alleviating the ecological risks in the forest landscapes of nature reserves.

Occurrence, potential sources, and ecological risks of traditional and novel organophosphate esters in facility agriculture soils: A case study in Beijing, China

Although traditional organophosphate esters (OPEs) in soils have attracted widespread interest, there is little information on novel OPEs (NOPEs), especially in facility agriculture soils. In this work, we surveyed 11 traditional OPEs, four NOPEs, and four corresponding organophosphite antioxidant precursors (OPAs) for the NOPEs in soil samples collected from facility greenhouses and open fields. The median summed concentrations of traditional OPEs and NOPEs were 14.1 μg/kg (range: 5.38–115 μg/kg) and 702 μg/kg (range: 348–1952 μg/kg), respectively, in film-mulched soils from greenhouses. These concentrations were much higher than those in soils without mulch films, which suggests that OPEs in soils are associated with plastic mulch films. Tris(2,4-di-tert-butylphenyl) phosphate, which is a NOPE produced by oxidation of (2,4-di-tert-butylphenyl) phosphite, was the predominant congener in farmland soils, with concentrations several orders of magnitude greater than those of traditional OPEs. Comparisons of OPEs in different mulch films and the corresponding mulched soils revealed that degradable and black films caused more severe pollution than polyethylene and white films. Traditional OPEs, including tris(2-ethylhexyl) phosphate and tricresyl phosphate, exhibited moderate risks in farmland soils, especially in film-mulched soils. NOPEs, including trisnonylphenol phosphate, posed high ecological risks to the terrestrial ecosystem. Risk evaluations should be conducted for a broad range of NOPEs in the environment.

Fate of pharmaceutical residue in two Romanian rivers receiving treated water: Occurrence, distribution and risk assessment

This study presents the first set of data on the removal of proton pump inhibitors (PPIs) and histamine H2 receptor antagonists (HRAs) and their transformation products in two Romanian wastewater treatment plants (WWTPs), as well as the impact of these organic pollutants on freshwater receiving effluents. The research investigated eight target pharmaceuticals and three metabolites using a newly developed and validated Liquid Chromatography - Mass Spectrometry (LC-MS/MS) method. The combined determination had a range of quantification limits varying from 0.13 ng/L to 0.18 ng/L for surface water and from 0.28 ng/L to 0.43 ng/L for wastewater. All analytes except cimetidine and 5-hydroxy-omeprazole were identified in water samples. The study found similar overall removal efficiencies for both WWTPs (43.2 % for Galati and 51.7 % for Ramnicu-Valcea). The research also showed that ranitidine and omeprazole could pose a low to high ecological risk to aquatic organisms. The findings suggest that the treatment stages used in the two Romanian WWTPs are insufficient to remove the target analytes completely, leading to environmental risks associated with the occurrence of pharmaceutical compounds in effluents and freshwater.

Assessment of occurrence, partitioning and ecological risk for 144 steroid hormones in Taihu Lake using UPLC-MS/MS with machine learning model

Steroid hormones (SHs) have attracted mounting attention due to their endocrine-disrupting effects on humans and aquatic organisms. However, the lack of analytical methods and toxicity data for a large number of SHs has limited the effective management of SH contamination in the water-sediment systems. In this study, we developed a highly sensitive analytical method for the simultaneous quantification of 144 SHs to investigate their occurrence, spatial distribution and partitioning in the water and sediment in Taihu Lake. The results showed that the total concentrations of SHs in water and sediment were 366.88–998.23 ng/L (mean: 612.84 ng/L) and 17.46–150.20 ng/g (mean: 63.41 ng/g), respectively. The spatial distribution of SHs in Taihu Lake might be simultaneously influenced by the pollution sources, lake hydrodynamics, and sediment properties. The sediment-water partitioning result implied that 28 SHs were in dynamic equilibrium at the water-water interface. In addition, 22 and 12 SHs tended to spread to water and settle into sediment, respectively. To assess the ecological risk of all SHs, a robust random forest model (R2 = 0.801) was developed to predict the acute toxicity of SHs for which toxicity data were not available from publications. Risk assessment showed that SHs posed a high ecological risk throughout Taihu Lake, with the highest risk in the northwestern areas. Estrone, 17β-estradiol and 17α-ethynylestradiol were the dominant risk contributors and were therefore recommended as the priority SHs in Taihu Lake. This work provided a valuable dataset for Taihu Lake, which would help to provide guidance and suggestions for future studies and be useful for the government to develop the mitigation and management measures.

Abundance and risk assessment of microplastics in water, sediment, and aquatic insects of the Nile River

Microplastics (MPs) are a serious threat in freshwater environments. The ecological risk and abundance level of MPs in abiotic and biotic compartments of the Nile River haven't been systematically reported. Thus, these issues were highlighted in the present study during different seasons of the sampling year. The results showed that MP concentrations in the river ranged from 2.24 ± 0.6 to 3.76 ± 1.1 particles/L, 298 ± 63 to 520 ± 80 particles/kg dry weight, and 0.081 ± 0.051 to 4.95 ± 2.6 particles/individual in surface water, sediment, and different species of aquatic insects, respectively. All the extracted MPs are colored blue, red, and black. Fiber-shaped polyesters (<500–1500 μm) were the most common MPs in all the river compartments. MPs' dominance was observed during the summer in comparison with that in the other seasons. Environmental risk indicators indicate the high ecological risk of MPs, which are widely distributed in the Nile River. In conclusion, MP consumption by aquatic insects may not only be related to levels of environmental contamination, since other variables, such as taxon size, weight, and particular feeding behavior, may also be significant. Additionally, the presence of MPs in insects (at lower trophic levels) creates the potential for predation-based inter-trophic level transmission. Thus, higher trophic-level investigations of various feeding groups should be carried out to identify any possible harm that MPs cause to various aquatic organisms.

Source and risk assessment of heavy metals in mining-affected areas in Jiangxi Province, China, based on Monte Carlo simulation.

In recent years, heavy metal contamination of soils has become a major concern in China due to the potential risks involved. To assess environmental pollution and human health risks in a typical heavy metal polluted site in Jiangxi Province, a thorough evaluation of the distribution, pollution levels, and sources of heavy metals in soils of the Yangmeijiang River watershed was conducted in this study. Positive matrix factorization and Monte Carlo simulation were used to evaluate the ecological and human health risks of heavy metals. The research findings indicate that heavy metal pollution was the most severe at the depth of 20-40cm in soils, with local heavy metal pollution resulting from mining and sewage irrigation. The high-risk area accounted for 91.11% of the total area. However, the pollution level decreased with time due to sampling effects, rainfall, and control measures. Leaf-vegetables and rice were primarily polluted by Cd and Pb. The main four sources of heavy metals in soils were traffic emission, metal smelting, agricultural activities and natural sources, mining extraction, and electroplating industries. Heavy metals with the highest ecological risk and health risk are Cd and As, respectively. The non-carcinogenic and carcinogenic risks of children were 7.0 and 1.7 times higher than those of adults, respectively. Therefore, children are more likely to be influenced by heavy metals compared to adults. The results obtained by the risk assessments may contribute to the identification of specific sources of heavy metals (e.g., traffic emissions, metal smelting, mining excavation, and electroplating industries). Additionally, the environmental impacts and biotoxicity associated with various heavy metals (e.g., Cd and As) can also be reflected. These outcomes may serve as a scientific basis for the pollution monitoring and remediation in the mining-affected areas.

Occurrence, removal efficiency, and emission of antibiotics in the sewage treatment plants of a low-urbanized basin in China and their impact on the receiving water

Sewage treatment plants (STPs) are primary sources of antibiotics in aquatic environments. However, limited research has been conducted on antibiotic attenuation in STPs and their downstream waters in low-urbanized areas. This study analyzed 15 antibiotics in the STP sewage and river water in the Zijiang River basin to quantify antibiotic transport and attenuation in the STPs and downstream. The results showed that 14 target antibiotics, except leucomycin, were detected in the STP sewage, dominated by amoxicillin (AMOX), ofloxacin, and roxithromycin. The total antibiotic concentration in the influent and effluent ranged from 158 to 1025 ng/L and 99.9 to 411 ng/L, respectively. The removal efficiency of total antibiotics ranged from 54.7 % to 75.7 % and was significantly correlated with total antibiotic concentration in the influent. The antibiotic emission from STPs into rivers was 78 kg/yr and 4.6 g/km2yr in the Zijiang River basin. The total antibiotic concentration downstream of the STP downstream was 23.6 to 213 ng/L and was significantly negatively correlated with the transport distance away from the STP outlets. Antibiotics may pose a high ecological risk to algae and low ecological risk to fish in the basin. The risk of AMOX and ciprofloxacin resistance for organisms in the basin was estimated to be moderate. This study established antibiotic removal and attenuation models in STPs and their downstream regions in a low-urbanized basin, which is important for simulating antibiotic transport in STPs and rivers worldwide.

Insights into polybrominated diphenyl ethers: occurrence, sources, and exposure health risk in selected solid waste impacted soils

&lt;p&gt;The Coordinated management of solid waste dumps from different anthropogenic environments is important for pollution management of immediate and adjacent ecosystems. This study took three soil profile samples from three functional zones: the rural, the suburban, and the urban solid waste dumps. The samples were analyzed for the concentration, origin, and associated risks of thirty-nine Polybrominated diphenyl ethers (Ʃ39PBDEs). Σ39PBDEs demonstrated high concentrations and ranged from 0.12 to 119 ng g−1 dw, in the order of rural &amp;gt; suburban &amp;gt; urban, and topsoil &amp;gt; subsoil &amp;gt; bottom soil. BDE-10, -11, -13, -15, -17, -99 and -119 showed relative abundance. Penta-BDE was moderately above standard and screening levels and demonstrated high and medium ecological risk in the rural and semi-urban zones. The non-carcinogenic and cancer risks highlight onsite exposure risks. PCA evaluation depicts an abundance of persistent and toxic flame retardant additives, and cluster analysis showed PBDEs were from a common source—cancer and hazard index exposure risk depicted rural &amp;gt; suburban &amp;gt; urban zone. The results suggested the continual use of banned flame retardant additives in commercial formulations. A comparison of PBDE implied that PBDEs in the suburban and urban zones could have undergone environmental processes, and the rural zone received fresh deposition. Migration and exposure to the detected -BDEs may increase the risk to humans in these zones. The results highlighted the need to establish a standard management protocol and monitor legacy pollutants in environmental and biological samples around solid waste dump sites and similar catchments.&lt;/p&gt;&#x0D;

Soil Contamination and Ecological Risk Assessment of Different Types of Lithuanian Shooting Ranges

ABSTRACT Contamination at shooting ranges is a growing concern due to the accumulation of potentially toxic elements in the soil. The aim of the study was to determine the level of soil contamination in different types of Lithuanian shooting ranges (clay-target, practical, small-bore) and assess the potential ecological risks. Soil samples were taken in two soil layer depths (0–10 cm and 10–30 cm) and locations (range floor and berm/target line) of different types of shooting ranges. The soils of the practical and small-bore shooting ranges were neutral, clay target – slightly alkaline. The soil of the clay-target firing range floor had a significantly lower organic matter, than small-bore and practical firing ranges. Lead contamination was significantly higher in the floor and berm surface soil and subsoil (about 1000 mg kg−1 and 360–527 mg kg−1, respectively) of the practice range compared to the others and controls. The Cd concentrations in the surface soil of the practical range and the small-bore firing ranges and in the soil of the berm were considerably higher than in the soil of the clay target. There was a significant negative correlation between soil pH and Pb and Cd concentrations. Pb content was positively correlated with organic matter content. The soils of the practical range floor and berm indicated high ecological risk. The research showed that heavy metal contamination is specific in different types of shooting ranges, therefore various management practices should be applied to prevent pollution in particular shooting range.

Regional assessment of the historical trends of mercury in sediment cores from Wider Caribbean coastal environments

Spatial and temporal variations of mercury (Hg) concentrations, enrichment, and potential ecological risks were studied in a suite of lead-210 (210Pb) dated sediment cores from 13 Wider Caribbean Region coastal environments. Broad variability of Hg concentrations (19–18761 ng g−1) was observed, encompassing even background levels (38–100 ng g−1). Most Hg concentration profiles exhibited a characteristic upward trend, reaching their peak values in the past two decades. Most of the sediment sections, showing from moderately to very severe Hg enrichment, were found in cores from Havana Bay and Sagua River Estuary (Cuba), Port-au-Prince Bay (Haiti), and Cartagena Bay (Colombia). These were also the most seriously contaminated sites, which can be considered regional Hg ‘hotspots’. Both Havana Bay and Port-au-Prince Bay reportedly receive waste from large cities with populations exceeding 2 million inhabitants, and watersheds affected by high erosion rates. The records from the Sagua River Estuary and Cartagena Bay reflected historical Hg contamination associated with chloralkali plants, and these sites are of very high ecological risk. These results constitute a major contribution to the scarce regional data on contaminants in the Wider Caribbean Region and provide reference information to support the evaluation of the effectiveness of the Minamata Convention.

Spatial Distribution, Risk Assessment and Sources of Heavy Metals in Roadside Soils Exposed to the Zhengzhou-Kaifeng Intercity Railway in Huanghuai Plain, China

ABSTRACT Heavy metal accumulation in soil can seriously harm human health, and it is necessary to identify the accumulation status and access the potential risks for local pollution control and sustainable economic development. This study evaluated the pollution level, spatial distribution, potential risk and sources of soil heavy metals along the Zhengzhou-Kaifeng intercity railway and compared pollution characteristics in north side soils with south side soils of the railway. A total of 260 soil samples were collected from a section along the railway. In practice, only the average Zn and Pb contents in soils were slightly higher than their corresponding risk screening values. The heavy metal enrichment in the north side soils was marginally lower than that in the south side soils. The spatial distribution of soil heavy metals except Pb could be mainly influenced by the different land use types. The geoaccumulation index and potential ecological risk of a single heavy metal indicated that Cd was the major contaminant with moderate pollution and high ecological risks in the south side soils and none to moderate pollution and moderate ecological risks in the north side soils. However, the mean multimetal potential ecological risk values suggested that the north side soils were at low ecological risks and the south side soils were at moderate ecological risks. The comprehensive non-carcinogenic risks and total carcinogenic risks for adults were low and acceptable, respectively. Pearson correlation analysis, PCA, and APCS-MLR analyses identified that the contributions of natural sources, mixed sources of industrial and traffic activities, agricultural activities, and other sources were 57.49%, 21.44%, 12.67% and 8.40%, respectively, and the major soil pollution Cd was mainly related to mixed sources of industrial and traffic activities. Therefore, continuous soil heavy metal monitoring is essential to elucidate the long-term railway operation effect on soil heavy metal accumulation.

Distribution, sources, partition behavior and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the waters and sediments of Lake Ulansuhai, China

This study represents the first comprehensive investigation of 16 polycyclic aromatic hydrocarbons (PAHs) in the waters and sediments of Lake Ulansuhai. It explores their occurrence, sources, transport behavior, and associated risks to human health and ecosystems. The results revealed that concentrations of ∑PAHs in dissolved phase and sediment with no significant seasonal differences. In contrast, ∑PAHs concentrations in suspended particulate matter were significantly higher during the ice-free period compared to the ice period. Spatially, the northern part of Lake Ulansuhai displayed higher PAHs content. Diagnostic isomeric ratios and PMF models indicated that the PAHs were primarily derived from combustion sources. The distribution of PAHs within water-sediment demonstrated that non-equilibrium status. Fugacity calculations indicated that 2–4 rings PAHs acted as secondary sources of sediment emissions. Toxicity assessment, indicated that PAHs posed no significant carcinogenic risk to humans. Risk quotient values showed that PAHs as low to high ecological risk.

Assessment of Heavy Metal Contamination and Ecological Risk in Soils Developed on Different Rock Types in Southern Bundelkhand Region, Central India

ABSTRACT This study assesses heavy metal (HM) concentrations and ecological risks in soils derived from granite (GrS), basalt (BtS), and amphibolite (AmS) rocks in southern Bundelkhand, central India. HM analysis reveals substantial variations, with Cr, Mn, Co, Ni, Zn, and Cd exhibiting higher concentrations in AmS, followed by BtS and GrS. Mn and Co content exceeds the Indian limit for soil (IS) and European Union (EU) guidelines for most samples. The geo-accumulation index shows high pollution levels of Cd in all soil types. Enrichment factor (EF) assessment reveals significant enrichment of Cd in GrS and BtS (mean 12.53, 6.91, respectively), and Cr, Ni, and Cd in AmS. The potential contamination index (Cp) and pollution load index (PLI) confirm Cd as the most significant contaminant in all soil types, with AmS exhibiting the highest pollution levels (29.31 and 650.68, respectively). The potential ecological risk (RI) assessment identifies Cd as the major contributor to ecological risk in all soil groups, with GrS and BtS displaying low to moderate risk, and AmS posing high to very high ecological risk. Our study highlights the influence of parent material on soil heavy metal concentrations, potentially leading to groundwater contamination and posing risks to human health.

Cross-contamination and ecological risk assessment of antibiotics between rivers and surrounding open aquaculture ponds

Antibiotics are causing widespread concern as one of the emerging contaminants. There is the abuse of antibiotics in high-density open aquaculture, and the tailwater is often discharged into surrounding rivers. At the same time, the water replenishment of open aquaculture ponds from nearby rivers containing antibiotic contamination from different sources may result in cross-contamination. However, it is still unclear which pollution intensity is greater in rivers or in open aquaculture. So in this paper, the levels of 20 antibiotics (i.e., Fluoroquinolones (FQs), Sulfonamides (SAs), Tetracyclines (TCs), Macrolides (MLs) and Lincosamides (LCs)) in rivers and high-density open aquaculture ponds were investigated in the Baini River basin in the suburbs of Guangzhou, China. The results showed that norfloxacin (NFX) was the predominant antibiotic in river and aquaculture water, with concentrations ranging from 6.12 to 156.04 ng/L and from 7.47 to 82.62 ng/L in both aquatic systems, respectively. As for the pollution intensity of antibiotics, the annual pollution contribution (28.64 kg/a) of the river water supply to open aquaculture is higher than that (10.81 kg/a) of open aquaculture to the river, which means river pollution has a greater impact on aquaculture ponds. The risk quotient (RQ) showed that the ecological risk of lincomycin (LIN), erythromycin (ERY), sulfamethoxazole (SMX), norfloxacin (NFX), ciprofloxacin (CFX) and chlortetracycline (CTC) in rivers and aquaculture environments had high ecological risks from 1.21 to 1.81. Water interactions with contaminated rivers will result in a corresponding increase in the ecological risk of antibiotics in the aquaculture environment. Overall, according to the results, the risk of polluted rivers to open aquaculture cannot be ignored, and it is recommended that open aquaculture should use these water sources with caution, and that the water quality evaluation of aquaculture water should be increased with monitoring indicators for emerging contaminants such as antibiotics.