Contamination Risk Assessment Research Articles

Groundwater contamination & health risk assessment with special reference to As in different tehsils of Bhakkar district

The present study was conducted to evaluate the concentration of arsenic in groundwater in Bhakkar district, Western Punjab Province, Pakistan. To analyze hydrochemical characteristics, 68 groundwater samples from various water schemes in four tehsils were taken. While most of the samples' concentrations of major cations and anions were within the WHO's maximum allowed range, almost 44% had higher arsenic levels than what was considered acceptable for drinking water. Gibbs diagrams were used to show how groundwater chemistry is affected by the dominance of rocks and evaporation crystallization. An investigation of the Indus River's lateral distribution and upstream to downstream locations' arsenic concentrations showed variability. According to the Health Risk Assessment (HRA), samples from Bhakkar tehsil (73.3%), Darya Khan tehsil (60%), and Kalur Kot tehsil (13.3%) all surpassed the hazard quotient level of “1,” whereas all samples from Mankera tehsil were within acceptable bounds. The hazard quotient numbers displayed a range of 0.038–5.127, with an average of 1.149 – suggesting that a considerable portion of people consuming water laden with high levels of arsenic may suffer from non-cancerous health complications. Moreover, the carcinogenic risk values were as high as 2.31 × 10−3, implying a heightened danger of cancer over the long term due to arsenic-contaminated water. It was determined that Bhakkar tehsil had the highest quantity of arsenic among the tehsils in the Bhakkar district, making the groundwater unfit for drinking.

Contamination Status, Environmental Factor and Risk Assessment of Polychlorinated Biphenyls and Hexachlorobutadiene in Greenhouse and Open-Field Agricultural Soils across China.

With the popularization and high-intensity utilization of greenhouse cultivation for crops growth, the pollution of greenhouse soils has been of concern. Therefore, a national-scale survey was conducted to investigate the contamination status, sources, influence factors and the risks of polychlorinated biphenyls (PCBs) and hexachlorobutadiene (HCBD) in greenhouse and nearby open-field soils. Contents of PCBs ranged from <LOD to 673.78 ng/g (mean: 77.38 ng/g) in greenhouse soils, and <LOD to 552.53 ng/g (mean: 61.90 ng/g) in open-field soils. HCBD was detected in all greenhouse soils with content ranging from 0.85 to 24.18 ng/g (mean: 8.33 ng/g), and a range of <LOD-20.19 ng/g (mean: 6.39 ng/g) in open-field soils. The sources of PCBs were the disposal of electrical equipment, domestic coal, wood burning emissions, etc. Levels of PCBs and HCBD were not correlated with the soil properties but positively correlated with Pseudomonas as the PCBs-degrader in open-field soils. Although the higher values of mean contents were found in greenhouses, the health risks of ΣPCBs in open-field soils were higher than in greenhouse soils due to the higher percentages of high-toxicity PCBs, especially the carcinogenic risks to children (>10-6). This study provided a full insight on the contamination status and risks of PCBs and HCBD when guiding greenhouse agriculture activities.

Ecological risk assessment of heavy metals contamination in agricultural soil from Al Majma'ah, central Saudi Arabia

Soil acts as a tank for heavy metals through surface complexation, ion exchange and surface precipitation. The purpose of this study was to assess the contamination and ecological risk of heavy metals (HMs) in agricultural soil in the Al Majma'ah area of central Saudi Arabia. Soil samples from 34 farms were collected, and HMs were evaluated using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (RI) were applied. The average values of the HMs (dry weight, mg/kg) had the following order: Fe > Al > Mn > Zn > Ni > Cr > V > Cu > Pb > Co > As. Results of contamination indices revealed low contamination, low risk and no enrichment for all HMs, except some minor enrichment for Zn and Ni. The considerable positive correlations between all elemental pairings in the correlation matrix and the one extracted principal component suggested that HMs in Al Majmaah soil were formed from weathering of Jurassic to Quaternary sediments in the research area.

Contamination and ecological risk assessment of Cr, As, Cd and Pb in water and sediment of the southeastern Bay of Bengal coast in a developing country

Safe levels of heavy metals in the surface water and sediment of the eastern Bay of Bengal coast have not been universally established. Current study characterized heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in surface water and sediments of the most important fishing resource at the eastern Bay of Bengal coast, Bangladesh. Both water and sediment samples were analyzed using inductively coupled plasma mass spectrometer. Considering both of the seasons, the mean concentrations of Cr, As, Cd, and Pb in water samples were 33.25, 8.14, 0.48, and 21.14 μg/L, respectively and in sediment were 30.47, 4.48, 0.20, and 19.98 mg/kg, respectively. Heavy metals concentration in water samples surpassed the acceptable limits of usable water quality, indicating that water from this water resource is not safe for drinking, cooking, bathing, and any other uses. Enrichment factors also directed minor enrichment of heavy metals in sediment of the coast. Other indexes for ecological risk assessment such as pollution load index (PLI), contamination factor (CF), geoaccumulation index (Igeo), modified contamination degree (mCd), and potential ecological risk index (PERI) also indicated that sediment of the coastal watershed was low contamination. In-depth inventorying of heavy metals in both water and sediment of the study area are required to determine ecosystem health for holistic risk assessment and management.

Ingestion and polymeric risk assessment of microplastic contamination in commercially important brachyuran crab Portunus sanguinolentus

Microplastic (MP) in seafood is a growing area of food safety. In the present study, MP contamination in the commercially important crab Portunus sanguinolentus was assessed. A total of 300 crab specimens were collected from three principal fishing harbors of Gujarat. The collected specimens were analyzed for MPs isolation using a previously published protocol. The specimens were dissected, and organs such as the gut and gills were placed separately in the beaker. The organic tissues were digested using 10% KOH. After the digestion, flotation and filtration processes were carried out for the extraction of MPs. The physical (shape, size, and color) and chemical characterization of MPs were performed. The average abundance of MP was recorded as 0.67 ± 0.62 MPs/g. The pollution indices revealed very high contamination and fell under class IV (Jakhau) and V risk categories (Okha and Veraval). Microfibers were found dominantly. Blue and black-colored MPs with 1–2 mm sizes were recorded dominantly. Polyethylene, polyethylene tetraphene, polyurethane, polystyrene, and polypropylene were identified as polymer compositions of MPs. Concludingly, the present study gives an insight into the MP in an important crab species P. sanguinolentus, which can be useful to design further investigations on the toxicity of MPs in seafood.

Risk Classification Assessment and Early Warning of Heavy Metal Contamination in Meat Products

Risk classification assessment and early warning systems are indispensable tools and technologies in the realm of regulatory control. Evaluating and issuing early warnings regarding heavy metal contaminants in meat products play a pivotal role in ensuring public safety and maintaining societal stability. In this study, we focused on heavy metal pollutants such as lead, cadmium, chromium, and arsenic. We collected national inspection data for meat products from 20 provinces in 2020. Combining dietary structure data, toxicology information, and dietary exposure assessment methods, we constructed a risk assessment model for heavy metal contaminants in food. Furthermore, we employed an entropy weight-based analytic hierarchy process (AHP-EW) to classify the results of the risk assessment for heavy metal contaminants in food. This involved determining risk rating levels and thresholds. Finally, we constructed a multi-step food contaminant risk prediction model based on the Transformer framework. To validate the model’s performance, comparative assessments were conducted across 20 datasets using various models. The results clearly indicate that the Transformer model outperformed the others in 14 datasets, excelling in its ability to provide advanced warnings for heavy metal risks in meat products. This empowers relevant authorities to strengthen their regulatory oversight of meat products based on the procedures and models proposed in this study, ultimately enhancing the efficiency of food safety risk management.

Correction: Yozukmaz, A.; Yabanlı, M. Heavy Metal Contamination and Potential Ecological Risk Assessment in Sediments of Lake Bafa (Turkey). Sustainability 2023, 15, 9969

The authors would like to make the following corrections to the published paper in [...]

Contamination and source-specific health risk assessment of polycyclic aromatic hydrocarbons in soil from a mega iron and steel site in China

The iron and steel industry has always been a key and difficult point of environmental pollution control. In the present study, 493, 175, 153, 72, and 42 soil samples were collected from the soil depths of 0–0.5, 0.5–2, 2–3, 3–4, and 4–5 m (herein called the layers) of the Shougang Steel site, respectively. Compared with the evaluation criteria, the Shougang Steel surface soil was severely polluted by polycyclic aromatic hydrocarbons (PAHs). Inverse distance-weighted interpolation and the Kruskal-Wallis H test revealed that the soil PAH pollution in the iron-making area, especially the coking area, was severer than those in other areas. The PAH concentrations first decreased, and then, increased with the increase of depth. With the increase in depth, the contributions of 2- and 3-ring PAHs increased, while those of 4-, 5-, and 6-ring PAHs decreased. The bivariate local indicators of spatial association (LISA) analysis was used to identify the areas prone to soil PAH pollution due to atmospheric deposition of industrial waste gas and traffic emissions. The method could be used to analyze the impact of anthropogenic activities on soil's PAH pollution for other contaminated sites. Three main pollution sources of soil PAHs, the backfill source, the combustion of coal, and the traffic emissions, were identified based upon three diagnostic ratios, positive matrix factorization and the bivariate LISA analysis, and accounted for 53.8%, 23.5%, and 22.7%, respectively. The combination of bivariate LISA analysis and other source analysis methods could improve the accuracy of source analysis. Benzo[a]pyrene contributed the most to the total health risk among sixteen PAHs. The health risks related to the three pollution sources decreased in the order of backfill sources > coal combustion > traffic emissions. The incremental life-time carcinogenic risks were all below 10−4, indicating negligible or acceptable risks.

Geochemical contamination of heavy metals and health risk assessment of coastal sediments along the North Chennai to Pondicherry, India using total reflection X-ray fluorescence spectroscopy (TXRF)

The present work aimed to assess the contamination and human health risk assessment of heavy metals (HMs) in 21 sediment samples collected from the North Chennai to Pondicherry coastal area of Tamil Nadu using total reflection X-ray fluorescence spectroscopy (TXRF). Enrichment factor (EF), contamination factor (CF), and geo-accumulation index (Igeo) were calculated to estimate sediment contamination. The average concentrations of HMs (mg kg−1 dry weight) were: Al (4305.12), V (25.77), Cr (15.08), Mn (83.39), Fe (4539.77), Ni (2.89), Cu (2.67), Zn (9.46), As (2.81), Hg (0.05), and Pb (0.92). Results of EF indicated no enrichment with Al, Ni, and Pb, moderate enrichment with V, and severe enrichment with As and Hg. Based on Igeo, all sediment samples showed unpolluted with HMs (except As and Hg). Based on total lifetime cancer risk (LCR), there are no significant health risks for people in the study area from carcinogenic Cr, As, and Pb.

Heavy metal contamination and health risk assessment of road dust from landfills in Dhaka-Narayanganj, Bangladesh

In the recent years, air pollution has become an alarming issue for human health in many rapidly growing megacities including Dhaka and Narayanganj. Herein, pollution status and health risk have been assessed by the road dusts collected from landfills in Dhaka and Narayanganj through determination of heavy metals including Pb, Cd, Cr, As, Cu, Ni, Zn and Mn using atomic absorption spectroscopy. The collected dust samples have been grouped into three sizes, for example, <300−>150, <150−>75 and < 75 μm, to assess the degree of heavy metal accumulation in the dust particles. The dust particles were accumulated with high concentrations of Pb and As at Matuail landfills, whereas Cd, Cr, Zn, and Mn concentrations were highest at Narayanganj landfills. The finer particles, for example 75 μm, accumulated substantial concentrations of heavy metals. Pollution index and pollution load index (PLI) results revealed that all of the sites were deteriorated by Pb, Cd, Cu, Zn and Ni. PLI results exhibited that the quality of the Matuail landfill area was severely deteriorated. In terms of non-carcinogenic health risk, the values of hazard quotient for ingestion were greater than those for inhalation and dermal pathways. For adult groups, hazard index values for the Matuail landfills and medical waste incineration sites were greater than 1, while for the children groups, the values for the same areas, including the Narayanganj landfills, were also larger than 1. These values were at least one order of magnitude higher for the children groups than for the adult groups. Given the results, it would be reasonable to draw the conclusion that non-carcinogenic health risks for children may be more prevalent in the relevant areas.

Geochemical fingerprinting to determine sediment source contribution and improve contamination assessment in mining-impacted floodplains in the Philippines

Constraining the main sediment sources and pathways across landscapes impacted by anthropogenic activity is essential to limit the dispersal of sediment-borne contaminants, especially in global conservation priority areas. This study examined the provenance, partitioning, and enrichment of metals in the floodplain of the mining-affected Santa Cruz catchment, The Philippines. Composite geochemical fingerprinting of fine sediment samples (n = 36) was performed using a stepwise statistical screening procedure (range test, Kruskal-Wallis H test, discriminant function analysis) to derive the optimum set of tracers. Using a standard unmixing model, flood deposits downstream of the mining areas were shown to be predominantly mining-induced (71.9 ± 7.7 %), followed by natural erosion from gullies and stream banks (15.1 ± 11.0 %) and agricultural sediment (13.0 ± 5.1 %). Element partitioning data (Log Kd = 1.3–6.6) during a high flow event indicated that metals are dominantly associated and transported via suspended particulate matter. Background concentrations of Ni and Cr were found to be orders of magnitude higher than the threshold values set by international sediment quality guidelines (SQGs), emphasizing the need for site-specific SQGs in mineralised areas. Enrichment factor values indicated low to significant contamination of flood deposits relative to natural and agricultural sediment (EF 1.0–5.5). Furthermore, it was demonstrated that using different conservative elements could considerably influence the enrichment factor calculation. Based on tracer screening tests, Th was shown to be the most suitable reference element. The findings provide new insights on the application of geochemical tracers in a mining setting and integrating fingerprinting approaches with traditional assessment techniques to improve the reliability of contamination risk assessment in other areas facing similar sediment pollution problems.

Characterization and Ecological Risk Assessment of Toxic Metal Contaminants in the Soil Around the Coal Gangue Hill in Huainan, Central China

Characterization and Ecological Risk Assessment of Toxic Metal Contaminants in the Soil Around the Coal Gangue Hill in Huainan, Central China

Source-specific probabilistic contamination risk and health risk assessment of soil heavy metals in a typical ancient mining area

Heavy metal pollution (HMP) from mining operations severely threatens soil ecosystems and human health. Identifying the sources of soil heavy metals (HMs) and assessing source-specific risks are critical for developing effective risk mitigation strategies. In this study, a combination of methodologies including PMF, Monte Carlo analysis, soil pollution risk index, and a human health risk assessment model were utilized to investigate soil HM risks in a typical ancient mining area in Daye City, China, considering both environmental pollution and human health impacts. Cu emerged as the most significant soil pollution risk, whereas As posing the highest health risk. About 48.44 % of the multi-element integrated soil pollution risk has escalated to the heavy level. Furthermore, around 22.42 % of the non-carcinogenic risk (NCR) and 9.53 % of the carcinogenic risk (CR) exceeded unacceptable thresholds (THI > 1 for NCR and TCR > 1E-4 for CR). The PMF model identified four distinct sources: the smelting industry, traffic emissions, a combination of agricultural and natural factors, and mining activities. The mixed agricultural and natural source significantly impacted health risks, contributing 42.17 % to NCR and 53.88 % to CR, followed by the mining source, contributing 31.67 % to NCR and 24.07 % to CR. Interestingly, the mining source contributed the highest soil pollution risk at 42.45 %, while the mixed agricultural and natural source exhibited the lowest at 16.33 %. Furthermore, the study explored source-specific risk components by evaluating the contributions of different sources to specific elements. The mining source was identified as the focus for soil HMP control, followed by the mixed agricultural and natural source. Overall, this study provided an in-depth analysis of soil heavy metal risks in mining areas from the source apportionment perspective, which broadened the research framework of soil heavy metal source analysis and risk assessment, potentially providing scientific guidance for managing regional soil HMP.

Predicting the impact and duration of persistent and mobile organic compounds in groundwater systems using a contaminant mass discharge approach

This study investigated methods for predicting the duration and impact on groundwater quality from persistent and mobile organic compounds (PMOCs) at a drinking water well field affected by multiple contaminant sources. The fungicide metabolite N,N-dimethylsulfamide (DMS), which frequently occurs above the Danish groundwater quality criterion (0.1 μg/L), was used as an example. By combining contaminant mass discharge (CMD) estimations, modeling, and groundwater dating, a number of important discoveries were made. The current center of contaminant mass was located near the source area. The CMD at the well field was predicted to peak in 2040, and an effect from the investigated sources on groundwater quality could be expected until the end of the 21st century. A discrepancy in the current CMD at the well field and the estimated arrival time from the studied source area suggested an additional pesticide source, which has not yet been thoroughly investigated. The presence of the unknown source was supported by model simulations, producing an improved mass balance after inclusion of a contaminant source closer to the well field.The approach applied here was capable of predicting the duration and impact of DMS contamination at a well field at catchment scale. It furthermore shows potential for identification and quantification of the contribution from individual sources, and is also applicable for other PMOCs. Predicting the duration of the release and impact of contaminant sources on abstraction wells is highly valuable for water resources management and authorities responsible for contaminant risk assessment, remediation, and long-term planning at water utilities.

MiR-20a-5p targeting mfn2-mediated mitochondria-lipid droplet contacts regulated differential changes in hepatic lipid metabolism induced by two Mn sources in yellow catfish

Understanding the hazards of different forms of metal elements provided innovative insights into their toxicity and environmental risk assessment. To date, few studies had been conducted to investigate the differential effects and mechanisms of MnO2 NPs and MnSO4, two widely distributed environmental pollutants, on hepatic toxicity and lipid metabolism since lipid metabolism-relevant parameters were broadly used as biomarkers for risk assessment of hazardous contaminants. Thus, using yellow catfish Pelteobagrus fulvidraco, an ecologically and economically important freshwater fish as the model, the present study investigated the differential effects and mechanisms of MnO2 NPs and MnSO4 influencing hepatic lipid metabolism. Compared to MnSO4, MnO2 NPs increased hepatic Mn content, induced lipotoxicity, up-regulated the mRNA expression of lipogenic genes, increased peridroplet mitochondrial (PDM) contents, intensified the contact between mitochondria and lipid droplets (LDs), and downregulated miR-20a-5p abundance. Importantly, miR-20a-5p targeted mfn2, which mediated the contact between mitochondria and LDs and influenced changes in lipid metabolism induced by MnO2 NPs. Mechanistically, the direct Mfn2-Plin2 binding and Mfn2 GTPase activity promoted the MnO2 NPs-induced interactions between mitochondria and LDs, which in turn influenced MnO2 NPs-induced changes in hepatic lipid metabolism. For the first time, our findings indicated the significant differences between the changes in body metabolism induced by nanoparticles and inorganic elements, which helped to illuminate different mechanisms governing the responses of aquatic vertebrates to hazardous metal pollutants (MnO2 NPs and MnSO4).

Contamination and environmental risk assessment of potentially toxic elements in the surface sediments of Northwest Persian Gulf

To assess the contamination sources, patterns, and environmental risk related to potentially toxic elements (PTEs) in the sediment of the region, ninety-seven surface sediment samples were systematically collected from the marine boundary of the Iranian coastal territory in the northwestern Persian Gulf. The concentrations of major and trace elements in the sediments can be ranked as follows: Ca > Al > Fe > Sr > Mn > Ba > Cr > Ni > V > Zn > Cu > Pb > As > Mo > Cd.The study found that Ca, As, Sr, and Cd showed significant enrichment, while Ni and Cr showed moderate enrichment. The ecological risk index analysis indicated a low risk level, with Cd contributing to 61% and As contributing to 26% of the estimated risk. Anthropogenic sources were found to be responsible for significant enrichment of As and Cd in the northwestern Persian Gulf, particularly near coastal areas and in the Musa estuary. High concentrations of Arsenic result from urban/agricultural wastewater, industrial activities, and gas/oil fields. Natural weathering, riverbank erosion, and aeolian inputs also contribute to Arsenic levels. Cadmium pollution comes from wastewater, shipping, oil tankers, agriculture runoff, and industrial factories. Nickel and Chromium were moderately enriched, mainly due to their natural occurrence in high concentrations in the soil of southern Iran. The study also revealed a significant correlation among the elements Al, Ni, Cr, Fe, Mn, V, Zn, and Cu, suggesting that these elements predominantly originate from lithogenous sources. The study highlights the importance of identifying and controlling sources of As, Cd, Ni, and Cr pollution in the northwestern Persian Gulf to protect the marine ecosystem and public health. The implementation and enforcement of stricter environmental regulations can reduce PTEs contamination in the region and safeguard the aquatic ecosystem and public health.

Boron contamination and related health risk assessment in the soils collected from olive groves in İzmir province, Türkiye

Although boron (B) is an essential element for plants, high levels are also toxic. In this respect, pollution of soils by B may pose a serious problem for ecosystem and human health. On the other hand, studies evaluating the ecological and human health risks that may arise due to B contamination in agricultural soils are limited. In this study, it was aimed to determine the B pollution degree of the soils taken from the olive groves of İzmir province, which is approximately 180 km away from the B deposits in the Bigadiç district. In addition, the factors affecting boron adsorption and availability were discussed and the ecological and health risks of boron were evaluated. For this, soil samples were collected at depths of 0–30 cm from 118 olive groves and their B, Al, Fe, pH and organic matter contents were determined. The mean B content (47.08 mg/kg) of the study area was comparable to world-soil average B concentration (42 mg/kg). Also, B had a “low potential ecological risk” in the study area according to the ecological risk index results. On the other hand, based on the results of contamination factor (Cf) and enrichment factor (EF), “moderate contamination” and “significant enrichment” were found in the study area for B. These findings indicated that the B content in the study area is mainly related to the soil parent material, but irrigation water also contributes slightly to B content. Correlation analysis results suggested that Al and Fe contents of the soils in the study area may have an effect on B adsorption. The results of health risk assessment indicated non-carcinogenic effects are not expected for adults and children exposed to soil B content by ingestion, dermal contact and inhalation.

Microplastics in fish culture ponds: abundance, characterization, and contamination risk assessment

Microplastics (MPs), an emerging pollutant, have drawn attention on a global scale and have been found in various ecosystems. Nevertheless, there is currently a lack of information regarding the contamination levels of MPs in aquaculture ponds worldwide. In this study, sediment and water samples were collected from five types of fish ponds, namely, homestead ponds (S1), commercial aquaculture ponds (S2), ponds near a residential area (S3), ponds near a small-scale industrial area (S4), and ponds near a large-scale industrial area (S5), to identify, characterize, and assess the contamination risk of MPs. Stereomicroscopic and Fourier-transform infrared (FTIR) spectroscopy analyses revealed that the MPs ranged from 3.33 item/kg to 136.67 item/kg in sediment and 16.6 item/L to 100 item/L in water samples. Overall, the abundance of MPs was extremely high in S5, followed by S4, S2, S3, and S1, which clearly showed the levels increased with the intensity of human activities. The levels of MPs in both sediment and water showed significant differences (p &amp;lt; 0.05) within and between ponds, as well as in comparison between water and sediment samples. The concentrations of MPs surpassed those noted in aquaculture ponds of different nations. The majority of MPs consisted of fragments and films in both sediment and water samples. Furthermore, transparent and white-colored MPs were the prevailing types found in the sediment and water samples of the aquaculture ponds. Around 34% of MPs present in sediment and 30% in water fell within the size range of 0.5–1 mm. Polymers like polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) were prevalent in both sediment and water samples. The contamination factor reached exceptionally elevated levels (&amp;gt;30 for sediment and &amp;gt;3 for water), signifying that the sampled regions, particularly S4 and S5 (industrial sites), displayed significant MP contamination. Moreover, the pollution load index values of the sediment (3.0 ± 1.5) and water samples (1.5 ± 0.3) also indicated the areas were contaminated with MPs. Multivariate analysis indicated that the elevated concentration of MPs in the studied region could be attributed to the discharge of effluents and other human-induced activities.

A One-Health environmental risk assessment of contaminants of emerging concern in London’s waterways throughout the SARS-CoV-2 pandemic

The SARS-CoV-2 pandemic had huge impacts on global urban populations, activity and health, yet little is known about attendant consequences for urban river ecosystems. We detected significant changes in occurrence and risks from contaminants of emerging concern (CECs) in waterways across Greater London (UK) during the pandemic. We were able to rapidly identify and monitor large numbers of CECs in n = 390 samples across 2019–2021 using novel direct-injection liquid chromatography-mass spectrometry methods for scalable targeted analysis, suspect screening and prioritisation of CEC risks. A total of 10,029 measured environmental concentrations (MECs) were obtained for 66 unique CECs. Pharmaceutical MECs decreased during lockdown in 2020 in the R. Thames (p ≤ 0.001), but then increased significantly in 2021 (p ≤ 0.01). For the tributary rivers, the R. Lee, Beverley Brook, R. Wandle and R. Hogsmill were the most impacted, primarily via wastewater treatment plant effluent and combined sewer overflows. In the R. Hogsmill in particular, pharmaceutical MEC trends were generally correlated with NHS prescription statistics, likely reflecting limited wastewater dilution. Suspect screening of ∼ 1,200 compounds tentatively identified 25 additional CECs at the five most impacted sites, including metabolites such as O-desmethylvenlafaxine, an EU Watch List compound. Lastly, risk quotients (RQs) ≥ 0.1 were calculated for 21 compounds across the whole Greater London freshwater catchment, of which seven were of medium risk (RQ ≥ 1.0) and three were in the high-risk category (RQ ≥ 10), including imidacloprid (RQ = 19.6), azithromycin (15.7) and diclofenac (10.5). This is the largest spatiotemporal dataset of its kind for any major capital city globally and the first for Greater London, representing ∼ 16 % of the population of England, and delivering a foundational One-Health case study in the third largest city in Europe across a global pandemic.

Ecotoxicological risk assessment of metalloid contamination in the sediment and benthic fauna of a tropical lotic freshwater ecosystem in Southern Nigeria

The increasing exposure of freshwater bodies to pollutants and the bioaccumulation of heavy metals in body parts of aquatic organisms has raised concerns on the ecotoxicological and human health risk. This study evaluated the potential ecological and human health risk of heavy metal pollution in sediment and benthic fauna (Caridina africana) of the Osse River, Edo State, Nigeria. Using requisite equipment, samples of water sediment and C. africana were collected at designated stations from September 2015 to February 2017. Heavy metal concentrations in samples were determined using atomic absorption spectrophotometer. Result showed heavy metal contamination with concentration profiles of Fe &gt; Zn &gt; Mn &gt; Cu &gt; Ni &gt; Pb &gt; Cr &gt; Cd &gt; V in sediments and Fe &gt; Zn &gt; Mn &gt; Cu &gt; Ni &gt; Cr &gt; Pb &gt; Cd &gt; V in C. africana. The potential ecological risk index (PERI) values classified stations 1, 2 and 4 as of low ecological risk (PERI ≤ 150), while station 3 (PERI ≤ 300) was classified as of moderate ecological risk. Human health risk assessment for heavy metals in C. africana indicated significant non-carcinogenic health risk (HI &gt; 1), and high carcinogenic risk to human health. The consumption of the contaminated C. africana, which is harvested in commercial quantities, portends health risk to the general public. There is need for urgent action in the abatement and regulation of identified anthropogenic activities responsible for the release of these heavy metals into the Osse River.