Potentially Toxic Elements Levels Research Articles

Seasonal variation and human health risk assessment of potentially toxic elements in pharmaceutical effluents around Ilorin metropolis, Nigeria.

Potentially toxic elements (PTEs) are widely released into the environment as a result of increased urban and industrial development in recent years. The bulk of PTEs are cancer-causing and harm human health by producing free radicals. As a result, it is crucial to monitor, evaluate, and limit the effects of the elements on human health. In this study, levels of PTEs (As, Cr, Cd, Ni, Co, and Pb) in pharmaceutical effluents discharged along the Asa River around the Ilorin metropolis and their seasonal variations were evaluated. Water samples were collected from eight different locations over a two-season period along the river and analyzed for PTEs using atomic absorption spectrophotometry and an inductively coupled plasma optical emission spectrometer. As, Cd, Pb, Cr, Ni, and Co had mean PTE values in the effluents (both seasons) of 0.0258, 0.0233, 0.00193, 0.0176, and 0.0164mg/L, respectively, with As and Pb surpassing the WHO standard. Maximum temperature and pH were measured for the physicochemical parameters in the wet season, whereas electrical conductivity and total dissolved solids were seen in the dry season. The average values of the metals in the human risk assessment for carcinogenicity were As > Cd > Pb > Cr > Ni > Co, with As above the recommended threshold in several locations. However, all of the metal hazard indices were < 1, indicating that the waters were suitable for domestic purposes. Nonetheless, the relevant authorities should mandate that pharmaceutical effluents be treated before being released into bodies of water.

Bioaccumulation of metals in muscle tissues of economically important fish species from black sea Lagoon lakes in Türkiye: Consumer health risk and nutritional value assessment

This study is the first comprehensive investigation into the levels of potentially toxic elements (PTEs) in the muscle tissues of various fish species (Carassius gibelio, Squalis cephalus, Esox lucius, and Tinca tinca) in Lagoon Lakes Akgöl and Semenit (LLAS), Samsun, Türkiye. A multidisciplinary approach was employed, integrating elemental analysis, health risk assessment, and source identification techniques to evaluate the distribution, sources, and health risks of PTE contamination in fish. The mean concentrations of toxic and trace elements (µg/kg) were determined in ascending order: Cd (5) < Co (8) < Cr (18) = Pb (18) < Ni (66) < As (163) < Cu (290) < Mn (798) < Fe (6150) < Zn (6250). In contrast, the concentrations of macro elements are provided in units of mg/kg, as follows: Mg (391) < Na (677) < Ca (1698) < P (2314) < K (3837), with notable variations across species. Health risk assessment methodologies indicated that PTE levels in fish muscle tissues generally fell below regulatory limits, indicating their safety for consumption. Noncarcinogenic risk assessment further documented the safety of consuming these fish species, with elevated maximum safe consumption quantity (MSCQ) values observed for all metals. In addition, the estimated daily intake of PTEs was found to be below reference doses, confirming the safety of consumption. Esox lucius demonstrated a highest abundance of essential nutrients (e.g., Ca, K, Mg, and P). Source identification techniques indicated that residential waste, lithogenic materials, and agricultural practices are significant contributors to PTE contamination. Overall, this research stresses the importance of monitoring PTE levels in fish, ensuring food safety and protect human health.

HERisk and statistical clustering integrated for health risk modelling of PTEs in natural water resources for drinking and sanitary uses

Potentially toxic elements (PTEs) are well-known for exposing living organisms and humans to different levels of risk. The present study aimed to evaluate the extent of exposure to health risks sustained by the inhabitants of different suburbs across Southeastern Nigeria as a result of contaminated water sources. There are existing literatures on human health risk assessment in the study region. However, this is the first study to report a detailed breakdown of the risks faced by nine age groups in the study area. This was achieved by integrating a novel code (HERisk), statistical clustering, and water quality data. Laboratory analysis showed that the levels of PTEs (Fe2+, Ni2+, Cr3+, and Pb2+) in 53.6%, 17.8%, 3.5%, and 46% of the samples were found to be above the recommended limits. Aggregated human health risk scores for ingestion and dermal routes revealed that children aged 1 to 2 years are the most vulnerable to health hazards. According to cumulative carcinogenic health risk values (0.00E+00 to 2.41E-04), samples proximal to regions with significant human activities expose the locals to a high risk of developing cancer via ingestion. Q-mode hierarchical cluster analysis successfully validated the classification schemes used for the interpretation of the HERisk code values, captured the patterns in the dataset, and brought forth new perspectives. The comprehensive approach detailed in this study can be adopted as a framework for ongoing monitoring and assessment of water quality.

Potential of Castanea sativa for biomonitoring As, Hg, Pb, and Tl: A focus on their distribution in plant tissues from a former mining district

Bioavailability of potentially toxic elements (PTEs) from the Earth's crust in the soil, e.g., As, Hg, Tl, and Pb, can pose a potential environmental and health risk because of human activities, especially related to mining extraction. The biomonitoring allows to detect PTE contamination through their measurement in living organisms as trees. However, the choice of which plant species and tissue to analyse is a key point to be evaluated in relation to PTE absorption and translocation. The aim of this work was to assess the As, Hg, Tl, and Pb distribution in Castanea sativa Mill. plant tissues, given its importance for both biomass and food production. The study identified two sites in the Alpi Apuane (Italy), with similar environmental conditions (e.g., elevation, exposure, forest type, and tree species) but different soil PTE levels. The topsoil was characterized, and the PTE fractions with different bioavailability were measured. The PTE concentrations were also analysed in chestnut plant tissues (leaves, bark, wood, nuts, and shells) in parallel with and evaluation of plant health status through the determination of micro and macronutrient concentrations and the leaf C and N isotope composition (δ13C or δ15N). Chestnut trees showed a good health status highlighting its suitability for Tl, As, Hg, and Pb biomonitoring, displaying a tissue-specific PTE allocation. Thallium and Hg were detected in all plant tissues at similar concentrations, As was found in leaves, wood, and nuts while Pb only in the bark. The δ15N negatively correlated with leaf Mn and Tl concentrations, suggesting possible changes in N source and/or plant metabolism due to the high contamination level and acid soil pH. Thallium in La Culla site trees was associated with its presence in the carbonate rocks but not in the topsoil, highlighting the potentiality of chestnut in providing valuable information for geochemical surveying.

A novel assessment of potentially toxic elements (PTEs) in water and sediment samples from the Indus River, Pakistan: An ecological risk assessment approach

Pakistan, a country with limited water resources and highly vulnerable to the adverse effects of climate change, faces numerous challenges in managing its water supply. In this sense, this study assessed potentially toxic elements (PTEs) in the surface water and sediments of Pakistan's Indus River and its tributaries. Key water quality parameters such as pH, electrical conductivity (EC), and total dissolved solids (TDS) were determined, with respective average values of 7.1, 40 μS/cm, and 208 mg L−1. The concentrations of Cd, Cr, Cu, Ni, and Zn in surface water samples averaged 26 μg L−1, 0.9 μg L−1, 1.4 μg L−1, 22 μg L−1, and 2.1 μg L−1, respectively. The general sediment PTE profile was Ni > Cd > Zn > Cu > Cr. Certain PTE levels exceeded recommended thresholds, indicating the establishment of environmental pollution. Calculated geo-accumulation index values suggested moderate to heavy pollution levels in sediment, with PERI (404) values reinforcing the ecological risk posed by elevated PTE concentrations. Furthermore, significant correlations were observed between specific PTE pairs in both water and sediment samples. This study contributes with novel insights into the distribution and ecological implications of PTE contamination in the Indus River and its tributaries, paving the way for ecological risk management efforts.

Pollution and Health Risk Assessment of Potentially Toxic Elements in Groundwater in the Kǒnqi River Basin (NW China).

Potentially toxic elements (PTEs) pose a significant threat to the groundwater system and human health. Pollution and the potential risks of PTEs in groundwater in the Kǒnqi River Basin (KRB) of the northwest arid zones of China are still unknown. A total of 53 groundwater samples containing eight PTEs (Al, As, Cd, Cu, Mn, Pb, Se, and Zn) were collected from the KRB, and the pollution levels and probabilistic health risks caused by PTEs were assessed based on the Nemerow Index (NI) method and the health risk assessment model. The results revealed that the mean contents of Al, As, and Mn in the groundwater surpassed the Class III threshold of the Standard for Groundwater Quality of China. The overall pollution levels of the investigated PTEs in the groundwater fall into the moderate pollution level. The spatial distributions of contents and pollution levels of different PTEs in the groundwater were different. Health risk assessment indicated that all the investigated PTEs in groundwater in the KRB may pose a probabilistic non-carcinogenic health risk for both adults and children. Moreover, As may pose a non-carcinogenic health risk, whereas the non-carcinogenic health risk posed by the other seven PTEs in groundwater will not have the non-carcinogenic risks. Furthermore, As falls into the low carcinogenic risk level, whereas Cd falls into the very low carcinogenic risk level. Overall, As was confirmed as the dominant pollution factor and health risk factor of groundwater in the KRB. Results of this study provide the scientific basis needed for the prevention and control of PTE pollution in groundwater.

Impacts of unregulated dumpsites: a study on toxic soil contamination, associated risks, and call for sustainable environmental protection in Nnewi, Nigeria

The accumulation of leachates from unlined dumpsites laden soil-water environment with toxic elements poses imminent threats to both the environment and humans. This study evaluated the seasonal levels of potentially toxic elements (PTEs), their health-related risks, contamination factors (CF), pollution load index, geo-accumulation index (Igeo), ecological risk index, polymetallic contaminant index and Nemerow's synthetic pollution index of soils near a waste dump in Nnewi, Anambra State, Nigeria. The PTE results indicated that levels of Cd (1.54–3.40 mg/kg) were above the World Health Organization's threshold limit for soil. The studied soil samples had PTE levels higher than the control samples due to their proximity to the dumpsite. The CF of the PTE in the soil indicated moderate to considerable contamination, while the control areas showed moderate contamination for both seasons. The pollution load indices of the soil indicated heavy and moderate pollution for the study sample (2.207–2.517) and control samples (1.445–1.659). However, the ecological risk indices ranged from 85.72 to 164.84, indicating a low ecological risk. The Igeo of the PTE in the soil ranged from unpolluted, moderately polluted to very strongly polluted. The Nemerow's synthetic pollution index values ranged from 3.560 to 3.564 for the study samples and 2.070–2.502 for the control samples, indicating heavy and moderate pollution of the soil respectively. The polymetallic contaminant index values for the study samples (23.22–26.43) and control samples (15.02–17.23) showed high and considerable contamination respectively. Health risk examination highlighted that both adults and children have a low risk for non-cancer health threat via ingestion route, while a high risk was obtained for children for cancer health dangers via ingestion routes. For the dermal pathway, children and adults have minimal chances of exposure to cancer risks, while a high exposure to non-cancer risk was observed for children. Pearson's correlation and principal component loadings revealed the sources of pollution to be of similar origins linked to anthropogenic activities. Awareness programs are necessary to educate the populace about the dangers of using contaminated soil for farming or recreational activities. The use of sanitary dumpsites should be encouraged and adopted as a waste disposal method by the government to mitigate the spread of PTE into the environment.

Potentially toxic elements contamination and ecological risk assessment in surface sediments of Moulouya Estuary (Northeastern, Morocco)

Potentially toxic elements (PTEs) in aquatic ecosystems are a major environmental concern posing serious risks to aquatic life and human health. Understanding their distribution, sources, and effects is crucial for effective environmental management and the protection of biodiversity and natural resources. This study assessed the variability, bioavailability, contamination degree, and ecological risks of PTEs in surface sediments of the Moulouya Estuary. The levels of PTEs were determined using an inductively coupled plasma-optical emission spectrometry (ICP-OES). The mean concentrations of PTEs can be classified in the following order: Zn > Cr > As > Pb >Cu > Cd. The highest values were found in sites (S2, S4, and S5) that receive metals from anthropogenic activities. The mineralogical study showed that the sediment studied is dominated by Ca, which influences the PTEs mobility and makes them bioavailable in the aquatic environment, which means aquatic organisms can easily assimilate them. The PTEs contamination degree was determined by several pollution indices (CF, CD, PLI, EF, Igeo), which indicate that surface sediment shows low to moderate contamination levels. However, the Potential Ecological Risk indicates a moderate to considerable risk in the study area. The multivariate analysis indicates that As, Zn, Cr, Pb, and Cu are derived from anthropogenic activities (urban wastewater, fertilizers, and fishing boats), while Cd could have mixed sources. The results highlight suggest that human activities pose an ecotoxicological risk in the Moulouya Estuary. To minimize these risks and protect the aquatic ecosystem and human health, periodic monitoring and management strategies should be continued. These measures will enable early detection of changes in PTE levels and the implementation of the necessary interventions to reduce their harmful effects.

Evaluating the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria

Contamination of borehole water by leachates from dumpsites has significantly affected the health of those who use polluted water for domestic activities. This study evaluated the seasonal variations of risks associated with potentially toxic elements in underground water sources near a dumpsite in Awka, Nigeria. The levels of the potentially toxic elements (PTEs) were compared with the World Health Organization (WHO) and Nigerian standard for drinking water quality (NSDWQ) standard limits. The, sources of PTEs, metal pollution index, water quality index, ecological risk, and health-related risks of using the underground water were evaluated. The chemical results indicated that levels of Cd and Pb were above the WHO and NSDWQ threshold limits for potable water. The Mn and Ni values were above the NSDWQ limits for potable water. The study borehole samples had PTE levels higher than the control samples due to their proximity to the landfill. The water quality index ranged from 1290.29 to 2243.04, showing that the water is unsuitable for drinking and other domestic uses. The metal pollution indices of the underground water samples were above 1, indicating that the water needs treatment before use. The health risk examination highlighted that children are more disposed to non-cancer risk than adults based on the hazard indices obtained. Also, the probability of cancer risks was high, showing that both children and adults are likely to be in danger of cancer risks. However, the ecological risk indices ranged from 11.187 to 51.581, indicating a low ecological risk. Pearson's correlation and principal component analysis revealed that the sources of pollution are from similar origins/sources linked to anthropogenic activities. Awareness programs are necessary to educate the populace about the dangers of using contaminated water. Effective waste management strategies and water treatment techniques should be implemented.

Investigation of Potentially Toxic Elements (PTEs) Concentrations in Natural and Synthetic Product Cosmetics Used in Lagos, Nigeria

The use of cosmetics in their various forms has been historical and still trending. Potentially toxic elements (PTEs) have been found to be critical constituents of these cosmetics, though as either functional ingredients or as impurities. This has raised health concerns such as; in kidney failures, heart diseases and birth defects. This study investigate the presence and levels of certain indexed PTEs in both natural and synthetic cosmetics and their associated health implications on users in Lagos State, Nigeria. Three natural product cosmetics namely; palm kernel oil (PKO), shear butter and ‘tiro’ labelled as NC1, NC2 and NC3 respectively, and five brands of synthetic product cosmetics (SPCs) labelled as SC1, SC2, SC3, SC4 and SC5 were selected for analysis based on questionnaire response to cosmetic use among Badagry women. The metal analysis done using ICPOES showed that NC3 is PTEs laden; Mn (38.132 + 8.195) ppm, Ni (42.04 + 2.331) ppm, Pb (65.341 + 3.064) and Zn (92.89 + 6.62) ppm. Mn concentration is the highest amongst all the SPCs, ranging from 17.56 + 2.09 ppm to 29.04 + 0.012 ppm. Ni concentration ranged from 0.506 + 0.073 ppm to 9.88 + 1.43 ppm. The presence of these PTEs could be attributed to unintended contamination from raw material or product processing, or deliberately added as part of the required ingredients as in the case of some synthetic cosmetics. The level of PTEs in the synthetic cosmetics were below the permissible limits set by WHO. However, the risk of bioaccumulation exists due to continuous use over time.

Occurrence of toxic elements in river areas along drains and groundwater resources: source of contamination and associated health risk.

The objective of the current research was to examine the water quality of the River Ravi and the River Sutlej, with a specific focus on potentially toxic elements (PTEs). Additionally, we sought to monitor the sources of pollution in these rivers by gathering samples from the primary drains that carry industrial and municipal waste into these water bodies. Furthermore, we aimed to evaluate the impact of PTEs in surface water on groundwater quality by collecting groundwater samples from nearby populated areas. A total of 30 samples were collected from these three sources: rivers (6 samples), drains (9 samples), and groundwater (15 samples). The analysis revealed that the levels of PTEs in the samples from these three resources having a mean value: arsenic (As) 23.5µg/L, zinc (Zn) 2.35mg/L, manganese (Mn) 0.51mg/L, lead (Pb) 6.63µg/L, and chromium (Cr) 10.9µg/L, exceeded the recommended values set by the World Health Organization (WHO). Furthermore, PTEs including (As 84%), (Zn 65%), (Mn 69%), (Pb 53%), (Cr 53%), and (Ni 27%), samples were beyond the recommended values of WHO. The results of the Principal Component Analysis indicated that surface water and groundwater exhibited total variability of 83.87% and 85.97%, respectively. This indicates that the aquifers in the study area have been contaminated due to both natural geogenic factors and anthropogenic sources. These sources include the discharge of industrial effluents, wastewater from municipal sources, mining activities, agricultural practices, weathering of rocks, and interactions between rocks and water. Spatial distribution maps clearly illustrated the widespread mobilization of PTEs throughout the study area. Furthermore, a health risk assessment was conducted to evaluate the potential adverse health effects of PTEs through the ingestion of drinking groundwater by both children and adults. Health risk assessment result show the mean carcinogenic values for As, Cr, Pb and Ni in children are calculated to be (1.88E-04), (2.61E-04), (2.16E-02), and (5.74E-05), respectively. Similarly, the mean carcinogenic values for the above mentioned PTEs in adults were recorded to be (2.39E-05), (3.32E-05), (1.19E-03), and (7.29E-06) respectively. The total hazard index values for As, Zn, Cr, Pb, Mn, Cu, and Ni in children were observed to be (9.07E + 00), (9.95E-07), (4.59E-04), (5.75E-04), (4.72E-05), (2.78E-03), and (5.27E-05) respectively. The analysis revealed that As has an adverse effect on the population of the study area as compared to other PTEs investigated in this study.

Influence of the use of remediated soil and agricultural drainage water on the safety of tomato fruits

The objective of this study is to assess the effectiveness of different techniques employed in remediating contaminated soil and wastewater ecosystems to ensure the safety of tomato fruits (Solanum lycopersicum L. var. cerasiforme) cultivated in these environments. Three biochemical techniques T1–T3, besides two controls CCU and CCT, were used to remediate contaminated soil ecosystems using rock phosphate, elemental sulfur, bentonite, phosphate-dissolving bacteria, and Thiobacillus sp. The contaminated agricultural drainage water was remediated by a down-flow hanging sponge (DHS) system. Two experiments were conducted: a pot experiment took place in the greenhouse at the National Research Center of Cairo (Egypt) and a field experiment was carried out at the basin site in the village of El-Rahawy, applying the optimal treatment(s) identified from the greenhouse experiment. The health risk assessment for potentially toxic elements (PTEs) in the harvested tomato fruits was conducted by calculating estimated daily intake (EDI) and target risk quotient (THQ) values. Results from the greenhouse experiment indicated the high effectiveness of the DHS technique in remediating El-Rahawy agricultural drainage water. The content of PTEs after remediation was significantly reduced by 100%, 93.3%, 97.8, and 77.8% for cadmium, copper, manganese, and zinc, respectively. The application of treated drainage water in employed reclaimed soil ecosystems led to a remarkable decrease in PTE levels, especially under T3 treatment; the reduction reached 89.4%, 89.5%, and 78.4% for nickel, copper, and zinc, respectively. The bioremediation technique also reduced the content of PTEs in tomato fruits harvested from both greenhouse and field experiments; the cadmium content, for example, was below detection limits in all treatments. The T3 treatment applied in the greenhouse experiment caused the highest percentage decrease among the employed PTEs in tomato fruits grown in the greenhouse. The same trend was also reached in the field experiment. Microbiological analyses of tomato fruits revealed that E. coli, Salmonella, or S. aureus bacteria were identified on tomato fruits harvested from either greenhouses or field experiments, showing that the counted total bacteria were higher under the field experiment compared to the greenhouse experiment. The health risk assessment parameter THQ was below 1.0 for all tested metals under all treatments. This means that no potential health risk is expected from consuming tomato products produced under the different employed remediation treatments. In conclusion, the employed bioremediation techniques successfully reduced the PTE content and microbial load in both soil and drainage water ecosystems and in harvested tomato fruits. Henceforth, no health risks are expected from the consumption of this product.

Assessment of carcinogenic and non-carcinogenic risk of exposure to potentially toxic elements in tea infusions: Determination by ICP-OES and multivariate statistical data analysis

BackgroundThe perennial evergreen tea (Camellia sinensis) plant is one of the most popular nonalcoholic drinks in the world. Fertilizers and industrial, agricultural, and municipal activities are the usual drivers of soil contamination, contaminating tea plants with potentially toxic elements (PTEs). These elements might potentially accumulate to larger amounts in the leaves of plants after being taken up from the soil. Thus, frequent monitoring of these elements is critically important. MethodsThe present study intended to determine PTEs (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in both tea leaves and infusions using ICP-OES. Various multivariate data analysis methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to elucidate the potential sources of PTEs contamination, whether from anthropogenic activities or natural origins. Additionally, Pearson's correlation coefficient (PCC) was calculated to assess the relationships between the variables under study. ResultsThe mean contents (mg/L) of all studied elements in tea infusions decreased in order Mn (150.59 ± 1.66) > Fe (11.39 ± 0.99) > Zn (6.62 ± 0.89) > Cu (5.86 ± 0.62) > Co (3.25 ± 0.64) > Ni (1.69 ± 0.23) > Pb (1.08 ± 0.16) > Cr (0.57 ± 0.09) > Cd (0.46 ± 0.09) > Al (0.05 ± 0.008), indicating that Mn exhibits the highest abundance. The mean concentration trend in tea leaf samples mirrored that of infusions, albeit with higher concentrations of PTEs in the former. The tolerable dietary intake (TDI) value for Ni and provisional tolerable monthly intake (PTMI) value for Cd surpassed the standards set by the WHO and EFSA. Calculated hazard index (HI < 1) and cumulative cancer risk (CCR) values suggest negligible exposure risk. ConclusionElevated levels of PTEs in commonly consumed tea products concern the public and regulatory agencies.

Potentially Toxic Elements (PTEs) Dispersion in Alluvial Deposits from Abandoned Mining Sites

In the watersheds of abandoned mining districts, it is common to find remains of former facilities and waste dams on stream banks and slopes—a situation that results in the transport and accumulation of metal(loid)s in alluvial deposits. To analyze this problem, an area of the former mining district of Linares–La Carolina (southern Spain) was selected to evaluate the contents and distributions of Ag, As, Ba, Cu, and Pb as potentially toxic elements (PTEs) found in the mineral paragenesis. Specifically, this study focused on the Siles Stream, which runs through a sector where underground mining for the exploitation of galena veins generated abundant mining wastes, mainly waste rock and tailings. Thirty-four sediment samples from the stream bed of the Siles Stream and two sediment samples from the Guadiel River, of which it is a tributary, were analyzed. Floodplain sediments were sampled in the stream banks at the middle and lower reaches (11 samples), as well as the riverine soils developed at the mouth of the Siles Stream (22 samples). The analyzed samples presented high levels of PTEs, in most cases with values much higher than the generic reference levels established by European and regional legislation for PTEs in soils. In the case of Pb, the main metal mined in this district, contents of up to 27,074 mg·kg−1 were observed in the stream bed sediments. Very high concentrations of Pb also appeared in the floodplain sediments, with maximum values in the middle course of the stream, where the concentration reached 43,692 mg·kg−1. With respect to the sediments of the Guadiel river bed, the Pb content was 699 mg·kg−1 before the confluence with the stream and 2537 mg·kg−1 downstream, which clearly reflects the influence of the contributions from the Siles Stream. The enrichment factors (EFs) show that the sediments present a severe to very severe anthropogenic influence for Ag, As, Ba, Cu, and Pb. The geoaccumulation index (Igeo) indicates that the entire basin is extremely polluted by Pb, to which As and Ag are added in the middle course of the stream. The potential ecological risk index (RI) and pollution load index (PLI) based on the contamination factor (CF) suggested that metal loads far exceeded the reference values. Selective chemical extraction methods were used to assess the potential bioavailability of these elements in sediment and soil samples. The results showed high concentrations of Pb in the exchangeable fraction, which poses a significant ecological risk and potential human health risks.

Combining approaches for environmental assessment of rehabilitated gold‐mining areas in the Eastern Amazon

AbstractMonitoring key soil and vegetation attributes in mining areas under environmental rehabilitation is essential to ensure that the intervention techniques are effective. There are several approaches to monitoring mining areas and their integration is necessary to process large amounts of information. Thus, this study aimed to (i) assess soil multi‐contamination with potentially toxic elements (PTE) and human health risks; (ii) obtain a soil quality index with soil fertility data; (iii) calculate spectral index; (iv) show rehabilitation status based on vegetation attributes, and (v) compile these indices in a single measure. Four tailings' ponds (TPs), two waste piles (WPs), and an area of native forest from a gold mine in the Carajás National Forest were evaluated. Soil quality and vegetation cover are good in forest areas, with no evidence of PTE contamination. On the other hand, the TPs have poor fertility and vegetation cover, as well as higher levels of PTE. Human health risk indices obtained for all PTE were lower than 1, indicating a low risk to human health. The results of integrating the different indices suggest that the environmental conditions of the WPs are better than those of the TPs, which are still far from the environmental conditions of native areas. Soil attributes and vegetation development in TPs areas could be enhanced by the incorporation of organic materials and fertilizers and by planting species with phytoremediation potential. Finally, the integrative approach of the different indices proved to be useful in assessing the rehabilitation progress of the areas.

Spatial variability and risk assessment of potentially toxic elements in the effluent of Kumasi Abattoir [sbnd] Ghana

Hypothesis-driven experiments have been conducted to explore the spatial variability and potential ecological risk indices (RIs) of potentially toxic elements (PTEs) in untreated in situ effluent continuously discharged downstream by the Kumasi Abattoir Ghana (KAG). The study focused on seven PTEs nickel (Ni), lead (Pb), cadmium (Cd), manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe), based on these hypotheses: (i) Variations in PTE levels may be significant in the effluent; (ii) Comparative RI assessments based on the three background values natural background values (NBVs) for freshwater, maximum admissible concentrations (MACs), and reference values (RVs) provide objective evaluations; and (iii) PTEs’ cluster distances are linked to RIs. Effluent samples were randomly collected in quintuplicates from the drainage receptacle and analyzed using standard methods. The spatial variability of PTEs was investigated using divisive hierarchical cluster analysis (DHCA). The RIs and their uncertainties were computed using Hakanson's equations and standard deviation (SD). PTE dispersion was analyzed using the coefficient of variation (CV). Analysis of variance (ANOVA) was employed to test for the significance of hypotheses 1 and 2, complemented by Scheffé's post-hoc test where significance was detected. Hypothesis 3 was investigated by analyzing PTE cluster distances and RIs based on Pearson's correlation metric. The DHCA produced two clusters Cd–Cu–Mn–Ni and Zn-(Fe)-Pb. The CVs (< 50 %) indicated medium variability, relatively uniform spatial distributions, and minimal fluctuations. High to very high RIs ± SDs obtained were 300 ± 57.5 (MACs), 2900 ± 500 (RVs), and 7666 ± 2980 (NBVs). The ANOVA yielded significant results for both hypotheses, while moderate to high correlations were obtained for the third hypothesis. While RIs provided compelling evidence of inimical effluent, the study highlights the influence of background values on RIs. It further suggests that the PTE cluster distances may be used as surrogates for the RIs.

Contamination levels of potentially toxic elements within the Ogun River estuary sediments, southwest Nigeria: Ecological and human health risk assessments

BackgroundThe Ogun River estuary is located at the northwestern corner of the Lagos Lagoon in southwest Nigeria. Metal smelting, petroleum products transport, sewage disposal and chemical production are activities within this region, which could lead to the release of potentially toxic elements (PTEs) into the immediate environment. This study investigates the contamination levels of PTEs in the Ogun River estuary sediments, with emphasis on ecological and human health risks. MethodsFourteen sediment samples were collected from the estuary through the Ogun River and Majidun environments. These samples were analyzed for PTEs including Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The contamination levels of sedimented PTEs from selected sample sites in the estuary were documented for ecological and health risk assessments. ResultsThe analysis revealed bulk concentrations of PTEs across the sampling stations. The contamination factor (CF) showed high contamination levels for Cd and Zn at sample sites 2, 14 and 16; while the other metals revealed moderate pollution indices across all the sites. The risk factor (Er) values of Cd at stations 2, 15 and 16 showed potential contamination. The canonical correspondence analysis (CCA) signified that the distribution of the PTEs is independent of the environmental factors, exposing significant anthropogenic input. Evaluations of the sediment quality revealed that PTEs such as Cd, Cu, Ni, Pb, and Zn, whose concentrations are above their TECs and ERLs, have little to no detrimental effects on sediment living organisms. The health risk assessment has shown that HI values for the elements fall within the non-carcinogenic risk range. The effects of the mean concentrations of these metals on the non-carcinogenic risk (HQ) for adults and children in decreasing order of impact are Co > Pb > Mn > Ni > Cd > Cu > Zn > Fe for both ingestion and dermal pathways. The human health risk index varies from low cancer risk in adult (LCR = 4.4 × 10−5) to moderate cancer risk in children (LCR = 4.1 × 10−4). ConclusionThis study has revealed the significance of anthropogenic input of PTEs into the environment. The sedimented PTEs are within permissible range, but monitoring and assessment activities should be focused on the Majidun axis since most metals show high concentration in this region.

Geochemical status of non-reclaimed ash dumps subjected to long-term self-overgrowing: Evidence from the Tyumen, Russia

Establishing the geochemical state of ash dumps of solid fuel thermal power plants in the absence of reclamation is extremely important in urban conditions. The current study was performed to assess the level, spatial distribution, soil pollution and risk of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in soils of abandoned ash dumps from the city of Tyumen, Russia. In general, the soils of as dumps had elevated levels of PTEs and PAHs compared to the crustal abundance and global soil background. A number of metals, namely Sr, Ni, Cu, Cr, Zn, and V, were concentrated in the soils of ash dumps (2–6 times), while As, Co, and Pb slightly exceeded the citywide average (up to 1.5 times). Naphthalene (NAP) was the only representative of the studied PAHs, the concentrations of which in the soils of ash dumps significantly exceeded the median content in urban soils of Tyumen. Elevated levels of NAP are likely a consequence of frequent fires occurring in grassy areas. Spatial patterns of pollutants are mainly controlled by the initial heterogeneity of technogenic substrates, rather than the post-depositional processes including vegetation and soil cover development. Low and moderate pollution and human health risks of PTEs and PAHs were revealed in topsoils of the studied sites. Although elevated levels of pollutants in coal ash dump soils are due to peat combustion, they pose less of an environmental risk than the more common coal ash dumps and are potentially suitable for a wider variety of management practices.

Potentially toxic elements (PTEs) and ecological risk at waste disposal sites: An analysis of sanitary landfills.

This study presents an analysis of soil contamination caused by Ni, Zn, Cd, Cu, and Pb at municipal solid waste (MSW) landfills, with a focus on ecological risk assessment. The approach aims to assess how different landfill practices and environmental conditions affect soil contamination with potentially toxic elements (PTEs) and associated environmental risks. Soil samples were collected from MSW landfills in Poland and the Czech Republic. The research included a comprehensive assessment of PTEs in soils in the context of global environmental regulations. The degree of soil contamination by PTEs was assessed using indices: Geoaccumulation Index (Igeo), Single Pollution Index (Pi), Nemerow Pollution Index (PN), and Load Capacity of a Pollutant (PLI). The ecological risk was determined using the Risk of PTEs (ERi) and Sum of Individual Potential Risk Factors (ERI). The maximum values of the indicators observed for the Radiowo landfill were as follows: Igeo = 4.04 for Cd, Pi = 24.80 for Cd, PN = 18.22 for Cd, PLI = 2.66, ERi = 744 for Cd, ERI = 771.80. The maximum values of the indicators observed for the Zdounky landfill were as follows: Igeo = 1.04 for Cu, Pi = 3.10 for Cu, PN = 2.52 for Cu, PLI = 0.27, ERi = 25 for Cd, ERI = 41.86. The soils of the tested landfills were considered to be non-saline, with electrical conductivity (EC) values less than 2,000 μS/cm. Varying levels of PTEs were observed, and geostatistical analysis highlighted hotspots indicating pollution sources. Elevated concentrations of Cd in the soil indicated potential ecological risks. Concentrations of Cu and lead Pb were well below the thresholds set by the environmental legislation in several countries. In addition, Ni concentrations in the soils of both landfills indicated that the average levels were within acceptable limits. Principal Component Analysis (PCA) revealed common sources of PTEs. The identification of specific risk points at the Radiowo and Zdounky sites contributes to a better understanding of potential hazards in landfill environments. By establishing buffer zones and implementing regular maintenance programs, emerging environmental problems can be addressed in a timely manner.

Chemical food safety of seaweed: Species, spatial and thallus dependent variation of potentially toxic elements (PTEs) and techniques for their removal

The increasing interest in seaweed as a food resource in Western societies raises concerns about associated potentially toxic elements (PTEs), including arsenic, cadmium, mercury, lead, and iodine. Hence, this study examined variation in PTEs by including samples of four different species (Ulva lactuca, Palmaria palmata, Alaria esculenta, and Saccharina latissima) from Ireland, as well as of a single species (S. latissima) from three different harvest sites and with different thallus parts analyzed from a single harvest site. Comparing different species from the Irish site, U. lactuca showed the overall lowest PTE levels, while S. latissima and A. esculenta had notably higher levels of arsenic (105±3 and 57.9±5.5 mg kg-1 DW, respectively) and cadmium (0.839±0.046 and 1.03±0.05 mg kg-1 DW, respectively), and S. latissima had highest iodine levels (2480±210 mg kg-1 DW). Lead was higher in P. palmata and U. lactuca but below maximum limits. Further analysis of S. latissima from three sites (Ireland, Norway, Sweden) showed site-specific variations in inorganic arsenic (0.192–9.69 mg kg-1 DW), lead (0.0751–0.269 mg kg-1 DW), and cadmium (0.554–1.16 mg kg-1 DW). Saccharina latissima from the Swedish site exhibited uneven PTE distribution in tissue of different age. In terms of tolerable intake levels, iodine and cadmium posed most concern for seaweed consumption. After processing, total ash content decreased, leading to reductions in total arsenic (61.1%), inorganic arsenic (92.4%), lead (49.4%), and iodine (72.8%). Cadmium and mercury were difficult to remove. This study offers insights into the chemical food safety of seaweed, both pre- and post-processing, for introduction into expanding European markets.Graphical abstract