Toxic Metal Contamination Research Articles

An analysis of the foremost issues with artisanal and small-scale gold mining from Ghana's perspective.

Ghana has abundant mineral reserves in many of its regions, and gold mining remains one of the country's main sources of revenue. Given Ghana's current position in the global gold market, this review provides insight into the ASGM sector to give an understanding of the pertinent issues in the sector and its role in the socio-economic development of the country. This review assesses the effects of ASGM operations in economic, social, health, and environmental contexts to raise awareness of issues related to ASGM. It evaluates the measures taken to lessen the consequences of ASGM and maintain the sector's long-term viability. This review considers the foremost issues, including continued Hg use in ASGM, recent use of cyanide in ASGM, pollution of water bodies, and toxic metal contamination. It takes into account sustainable measures and remedial techniques that Ghana has implemented to alleviate the negative effects and support best mining practices. The primary factors influencing people to participate in ASGM are the need for quick sources of income, the scarcity of jobs in rural areas, the economic hardship, the need to supplement earnings from other activities like trading, and the comparatively meager profits from agricultural activities. Findings indicated that to gain more traction in addressing the challenges in the ASGM sector, the involvement of the community and direct stakeholders is essential to promoting responsible mining and environmentally sustainable practices. This review will increase awareness and pressure on decision-makers, researchers, and ASGM communities about the relevance of environmental conservation and sustainability.

Pollution index of soils along and against the wind direction within a 40 km distance of Morupule Fly Ash Dumpsite, Botswana

AbstractArsenic, chromium, copper, lead, and zinc concentrations were measured in the leeward and windward directions within 40 km of the Morupule power station to assess the long‐term effects of fly ash deposition on the hazardous metal contamination of soils. Based on the quantities of these metals in the soil, the contamination factor, pollution load index, and potential ecological risk index were calculated to determine the potential of these metals will harm the ecosystem and human health. The results showed that areas (0.1–2 km) nearer to the dumpsite, especially in the leeward direction had higher contamination factors, 3.08–3.51 for Cr, 4.28–5.18 for Cu, and 3.10–3.17 for Pb. On the same distance, along the windward direction, the average contamination factor was 1.17× for Cr, 1.31× for Cu, and 1.7×x for Pb, less than that of the leeward direction. On the other hand, the potential ecological risk index was low for all the toxic metals being less than 40 index value independent of the wind direction. Similarly, the comprehensive ecological risk of various toxic metals indicated that the study area had a low ecological exposure as the index value was below 150. Overall, the toxic metal contamination in the soil due to the contamination factor is moderately polluted to unpolluted, especially on the leeward side, and the ecological risk of contamination is low across the study area, but continuous deposition of fly ash without proper management will increase the ecological risk.

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

Toxic Metals Contamination of Cattle Hide Singed With Scrap Tyres

Processed cattle hide popularly known as “Ganda” in Nigeria is widely eaten as a substitute for meat but the commercial method of processing this food delicacy through singeing with scrap tyres has become a source of concern due to possible heavy metals contamination. This study evaluates the presence and levels of Cd, Cu, Fe, Pb, and Zn in the cattle hide samples obtained by using Atomic Absorption Spectrophotometry (AAS). The hide samples analyzed were obtained from seven states across the three geopolitical zones in northern Nigeria. Cd was not detected in most of the samples, notably from Niger, Zamfara, Adamawa and Plateau states, while concentrations of 0.0001±5.77E-5, 0.0005±4.71E-5, and 0.009±0.001 mg/kg detected from Kano, Kaduna, and Taraba, respectively, were lower than the maximum permissible level of 0.05 mg/kg set by the reference limits. Pb concentrations in all the samples analyzed were 1.080±0.072 to 1.760±0.160 mg/kg which surpassed the maximum permissible level of 0.1 mg/kg set by the reference limits, while other heavy metals were below the safe limits. The high levels of Pb introduced to the singed hide beyond the reference limits could be linked to the use of scrap tyres in the burning hairs of the hide, and it could be of great concern after consumption. In view of the above possible health implications that might arise, a detailed and proper health risk assessment technique needs to be employed in future research.

Arsenic exposure and increased C-reactive protein are independently associated with lower erythrocyte glutathione peroxidase activity in Bangladeshi children

Toxic metal contaminants present in food and water have widespread effects on health and disease. Chalcophiles, such as arsenic, cadmium, and mercury, show a high affinity to selenium and exposure to these metals could have a modulating effect on enzymes dependent on selenocysteine in their active sites. The aim of this study was to assess the influence of these metals on the activity of the selenoprotein glutathione peroxidase 1 (GPX1) in erythrocytes of 100 children residing in rural Bangladesh, where drinking water often contains arsenic. GPX1 expression, as measured using high-throughput immunoblotting, showed little correlation with GPX activity (rs = 0.02, p = 0.87) in blood samples. Toxic metals and selenium measured in erythrocytes using inductively coupled plasma mass spectrometry (ICP-MS) and C-reactive protein (CRP) measured in plasma, were all considered as effectors of this divergence in GPX enzymatic activity. Arsenic concentrations in erythrocytes were most influential for GPX1 activity (rs = −0.395, p < 0.0001), and CRP levels also negatively impacted GPX1 activity (rs = −0.443, p < 0.0001). These effects appear independent of each other as arsenic concentrations and CRP showed no correlation (rs = 0.124, p = 0.2204). Erythrocyte selenium, cadmium, and mercury did not show any correlation with GPX1 activity, nor with CRP or arsenic. Our findings suggest that childhood exposure to inorganic arsenic, as well as inflammation triggering the release of CRP, may negatively affect GPX1 activity in erythrocytes.

DNAzyme-driven bipedal DNA walker and catalytic hairpin assembly multistage signal amplified electrochemical biosensor based on porous AuNPs@Zr-MOF for detection of Pb2+

As a highly toxic and refractory heavy metal contaminant, Pb2+ seriously endangers human health. The problems of low sensitivity and high cost of signal labeling widely exist in common electrochemical biosensors. Herein, a Pb2+ electrochemical biosensor was constructed using a DNAzyme-driven bipedal DNA Walker and catalytic hairpin assembly as the multistage signal amplification strategy. Compared with Zr-MOF, AuNPs@Zr-MOF has a larger porosity and specific surface area, which can effectively load MB to amplify the current signal. Pb2+ can trigger a dual signal amplification reaction to gradually accumulate the signal of methylene blue/gold nanoparticle @ zirconium-based metal organic frameworks (MB/AuNPs@Zr-MOF) on the electrode. The ingeniously designed sensing strategy realized the analysis of Pb2+ with a wide linear range from 0.05 to 1000 nmol/L and a lower limit of detection (LOD) of 4.65 pmol/L. In addition, the sensor has strong anti-interference ability and can accurately detect Pb2+ in various food samples.

Human health risk assessment of potentially toxic elements in soil and air particulate matter of automobile hub environments in Kumasi, Ghana

Rapid urbanization and uncontrolled industrial activities in developing countries have raised concerns about potentially toxic metal contamination of the environment. This study assessed the levels of potentially toxic elements in soil and airborne particulate matter in the Suame and Asafo areas in the Kumasi metropolis, characterized by a high concentration of auto mechanic workshops and residential settlements. X-ray fluorescence analysis and inductively coupled plasma-mass spectrometry were used to determine the metal concentrations in the samples. The results showed high concentrations of potentially toxic elements in the soil and air samples, indicating contamination from automotive activities. Metals such as Co, Ni, Pb, and Zn were found to be present at concentrations (13.42–6101.58 mg/kg and 14.15–11.74 mg/kg for Suame and Asafo respectively) that pose potential health risks to exposed populations. Mathematical models such as pollution indices were used to assess the extent of contamination and determine the potential sources of the metals - the automotive repairs. The findings highlight the urgent need for environmental management and remediation strategies to mitigate the health risks of exposure to potentially toxic elements in the Kumasi metropolis automotive hub.

Environmental Risks Study of Toxic Metals Contamination for Medical Wastes

Three Hospitals in Iraq were selected as the subject of this study. The study included studying the environmental risks resulting from the process of treating hospital waste by random burning by taking ash samples from the burned waste of the studied hospitals, determining the concentrations of toxic metals present in them, comparing this with the internationally defined levels, and indicating the extent of environmental hazard. The results of the laboratory analysis of fifteen samples of ash from the studied hospitals showed that in all these hospitals the ash contains toxic heavy metals, including lead (Pb), cadmium (Cd), and chromium (Cr). It was found that the concentrations of the elements in these toxic metals all exceed the limits permitted by the World Health Organization (WHO) (5, 1, and 5) mg/lliter, as the highest concentration of the lead metal, Pb, was (78.11) mg/lliter in the The third hospital. The highest concentration of cadmium (Cd) is 9.13 mg/lliter in the second Hospital, and the highest concentration of chromium (Cr) is 51.73 mg/lliter in the third Hospital, and it was found that there is no mechanism for disposal of this ash, which makes it a real threat to pollution of ground water and threatens human and animal life if contacted or inhaled.

Monitoring the spatial distribution patternaccording to urban land use and health risk assessment on potential toxic metal contamination via street dust in Ankara, Türkiye.

The urbanization processes with growing vehicle numbers cause heavy metal pollution in street dust, and high populations in metropolitan cities are exposed to pollutants. This paper aims to monitor the spatial distribution of heavy metals and evaluate the concentrations via health risk assessment of HMs (Cu, Ni, Cd, Co, Pb, and Zn) that expose the inhabitants to health hazards. According to the results of the current study, sixty street dust samples were applied to the acid digestion technique and quantification by inductively coupled plasma-mass spectrometry (ICP-MS). The spatial distribution of the selected heavy metals in the street dust was investigated using the spatial analysis tool in ArcGIS 10.0 according to population density and land use. In the present study, we used hazard index and cancer risk methods to estimate the public health risk of the pollutants exposed to street dust in Ankara. The concentrations range of the elements in street dust over the study area ranged from 3.34-4.50, 31.69-42.87, 16.09-21.54, 42.85-57.55, 0.00-3.51, and 23.03-30.79, respectively. The overall decreasing order of mean concentration of metals was observed as follows: Pb > Cu > Ni > Co > Cd > Zn. Vehicle traffic and industrial activities seem to be the most critical anthropogenic sources responsible for dust pollution in the study area. The risk assessment of Pb and Ni exposure was the highest, and the hazard index values were 2.42E + 00 and 2.28E + 00 mg/kg/day for children. However, the effect on adults was 2.62E-01 and 2.37E-02 mg/kg/day, followed by inhalation and dermal contact with street dust was almost negligible. The decreasing concentration is modeled spatially along the western development corridor of the city. The risk to public health is high in areas with high densities close to the city center and the main artery.

Spatial Patterns, Possible Sources, and Risks Assessment of Soil Potentially Toxic Elements in an Open Pit Coal Mining Area in a Typical Arid Region

Intensive mining activities in large-scale opencast coal mines have had a significant impact on the local environment. Elements that are potentially harmful to the environment are brought to the surface from deep underground, altering the geochemical conditions for their transport and redistributing them to the surface, causing serious local pollution. However, in-depth studies of toxic metal contamination in soils of arid coal mining areas have not yet received the attention they deserve. Although previous studies have conducted a great deal of research on heavy metal elements in surface coal mine soils, there are few studies related to the more seriously polluted surface coal mines in the arid regions of Northwest China, and there are no in-depth studies on the ecology of soil heavy metal contamination, health risks and source analysis according to the authors’ knowledge. To make up for this shortcoming, the present study takes Zn, Cu, Cr, Pb, Hg, and As in the surroundings of the tertiary coal mines in the Hongsachuan Mining Area (northern Xinjiang, China) as an example. The health, ecological risks, and pollution sources of heavy metal elements in surface coal mine soils were comprehensively analyzed. The results showed that the average concentrations of Cr, Hg, and As in the soils of open-pit coal mines greatly exceeded the corresponding provincial background values, with the Cr content exceeding China’s soil environmental quality standard Ⅰ and the As content even higher than standard Ⅱ (GB15618-1995). Geostatistical and multivariate statistical results showed that the six metals analyzed in this study can be divided into four groups, as follows. Group 1 included Zn and Cu and was mainly controlled by natural sources related to soil parent materials. Group 2 consisted of Cr and Hg and was associated with industrial practices. Group 3 was explained by As and was mainly from coal combustion during the mining activities. Group 4 was Pb and was dominantly from natural sources, together with vehicular emission during the mining activities, indicating a mixed source. Potential ecological risk index (PER) values exhibited low ecological risk in contaminated soils with Zn, Cu, Pb, and Cr, and only 10% of As samples exhibited moderate risks, while 77% of Hg samples posed ecological risks at different level, implying that Hg was the main contributor for comprehensive risk index (RI). Regardless of non-carcinogenic and carcinogenic health risk assessment, As was the primary risk element followed by Cr, and children tended to have a higher health risk than adults. In this paper, statistical methods, pollution assessment methods, and potential ecological risk models are skillfully combined, and relevant conclusions are drawn based on the human and economic geographical background information of the study area. The results can provide references for the investigation and evaluation of soil heavy metals and quantitative analysis of pollution sources in the same type of areas. In order to grasp the pollution level of potential toxic elements in the soil of large open-pit coal mines in arid areas, effective source-cutting measures are taken to provide data support the sustainable management of coal mines and local soil safety utilization measures.

The Role of Lignin in the Compartmentalization of Cadmium in Maize Roots Is Enhanced by Mycorrhiza.

In nature, arbuscular mycorrhizal fungi (AMF) play a crucial role in the root systems of plants. They can help enhance the resistance of host plants by improving the compartmentalization of toxic metal contaminants in the cell walls (CWs). However, the functions and responses of various CW subfractions to mycorrhizal colonization under Cd exposure remain unknown. Here we conducted a study to investigate how Cd is stored in the cell walls of maize roots colonized by Funneliformis mosseae. Our findings indicate that inoculating the roots with AMF significantly lowers the amount of Cd in the maize shoots (63.6 ± 6.54 mg kg-1 vs. 45.3 ± 2.19 mg kg-1, p < 0.05) by retaining more Cd in the mycorrhized roots (224.0 ± 17.13 mg kg-1 vs. 289.5 ± 8.75 mg kg-1, p < 0.01). This reduces the adverse effects of excessive Cd on the maize plant. Additional research on the subcellular distribution of Cd showed that AMF colonization significantly improves the compartmentalization of 88.2% of Cd in the cell walls of maize roots, compared to the 80.8% of Cd associated with cell walls in the non-mycorrhizal controls. We observed that the presence of AMF did not increase the amount of Cd in pectin, a primary binding site for cell walls; however, it significantly enhanced the content of lignin and the proportion of Cd in the total root cell walls. This finding is consistent with the increased activity of lignin-related enzymes, such as PAL, 4CL, and laccase, which were also positively impacted by mycorrhizal colonization. Fourier transform infrared spectroscopy (FTIR) results revealed that AMF increased the number and types of functional groups, including -OH/-NH and carboxylate, which chelate Cd in the lignin. Our research shows that AMF can improve the ability of maize plants to tolerate Cd by reducing the amount of Cd transferred from the roots to the shoots. This is achieved by increasing the amount of lignin in the cell walls, which binds with Cd and prevents it from moving through the plant. This is accomplished by activating enzymes related to lignin synthesis and increasing the exposure of Cd-binding functional groups of lignin. However, more direct evidence on the immobilization of Cd in the mycorrhiza-altered cell wall subfractions is needed.

Levels of toxic and trace metals in the breast milk of lactating mothers in Abeokuta, Ogun State, Nigeria

Background and objectivesBreast milk is an essential source of nutrients and energy for infants. The study analyzed for the levels of essential, toxic and rare earth elements in the breast milk of lactating mothers within Abeokuta metropolis. Materials and methodsThirty-seven (37) breast milk samples were collected with consents of lactating mothers at Ogun State General Hospital in Abeokuta. The samples were digested using standard method and analyzed for essential, toxic and rare earth elements using Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The data were subjected to descriptive analysis. ResultsThe results showed higher concentrations of toxic elements than essential elements in the breast milk of lactating mothers, where five toxic metals: Ag, Ti, V, Pb and Ba were observed to be present in 11, 14, 15, 17 and 23 breast milk samples respectively. Two essential (P and S) and two toxic (Cd and Hg (except sample 19)) elements were observed to be present in all the breast milk samples. Rare Earth Elements (except Sr, U and Rb) were below the detection limit of the instrument. Though three breast milk samples (12, 14 and 17) were observed safe, they contained two toxic (Cd and Hg) and a rare earth trace (Rb) element. ConclusionIt could be concluded that despite the inherent benefits of human breast milk with essential elements to the infants, it can still be a source of toxic and trace earth metals contamination.

Potential toxic phthalates and heavy metals contamination in vinegars and human health risk assessment

Phthalate acid esters (PAEs) and heavy metals (HMs) are well-known contaminants due to their toxic effects on human health. Daily food consumption is one of the critical ways of exposure to these contaminants for the human population. In this study, residue profiles and levels for eight phthalate esters and four heavy metals were evaluated in polyethylene terephthalate and glass bottled vinegars from the Turkish market. PAEs and HMs were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma mass spectrometry (ICP-MS). Packaging polymers were characterized by attenuated total reflection-fourier transform infrared spectroscopy (ATR/FT-IR) spectroscopy. Furthermore, non-carcinogenic health risk assessment was performed based on regular vinegar consumers' daily oral intake rates. Principal component analysis was carried out to evaluate and distinguish between types of vinegar samples. Bottle type, pH, and electrical conductivity values were effective parameters, to some extent, on PAEs and HMs contents of vinegar samples. The concentration ranges were <LOD-22.8 and 0.02–970 µg L−1 PAEs and HMs, respectively. Dimethyl phthalate (DMP) and dibutyl phthalate (DBP) were the most abundant PAEs, while aluminum (Al) was the predominant HMs. Butyl benzyl phthalate (BBP), diisononyl phthalate (DiNP), diisodecyl phthalate (DiDP), di(n-octyl) phthalate (DnOP), and inorganic mercury (iHg) were not detected in any sample. Non-carcinogenic risk assessment associated with vinegar consumption showed that the exposure to PAEs (ranging between 2.82 ×10−6 and 4.07 ×10−4 μg/kg bw day−1) and HMs (ranging between 2.06 ×10−5 and 5.24 ×10−2 μg/kg bw day−1) were well below the permissible limits. The findings showed that the levels of PAEs and HMs exposed through commercial vinegars were not significant enough to pose a health risk among individuals aged 18–65.

A potential sustainable technique to entrap contaminants against rill erosion based on MICP

Health risks due to toxic metals (TM) contamination is a global concern. Toxic metals could be release to the environment due to soil erosion. The present study was aimed to prove the synergistic mechanisms of microbially induced calcium carbonate precipitation (MICP) on improving the strength properties of soil particles toward rill erosion, as well as immobilizing toxic metals into stable crystals. Hence, laboratory batch studies were conducted to evaluate the rill erosion stability as well as Cd, Pb and Zn removal ability based on bioprecipitation through MICP, using urease producing bacteria. Results revealed that the application of the strain Bacillus pasteurii PTCC1645 in MICP process of test model treated with 500 mM cementation solution showed a great potential to decrease sand lost to below 20% with the flow rate of 15 ml/min with highest strength (131 KPa) and the highest calcium carbonate content (0.84%). Moreover, the immobilization of the toxic metals in biotreated test models above 50 mM under the flow rate of 3 ml/min showed the efficiency of Pb, Zn and Cd ions by 100%. SEM proved the presence of calcite among the sand particles which could be attributed to the effectiveness of the strain. Energy-dispersive X-ray spectroscopy(EDS) analysis revealed the presence of toxic metals, while were transformed into carbonates by MICP of PTCC1645. Hence, toxic metals have stronger stability encountered with rill erosion and low toxicity compared with metal ions. The present study illustrated that the carbonate-biomineralization can offer an effective and eco-friendly approach to immobilize soluble toxic metals and that MICP may play an important role in metal bioconservation during rill erosion.

Potentially toxic metals contamination, health risk, and source apportionment in the agricultural soils around industrial areas, Firozabad, Uttar Pradesh, India: a multivariate statistical approach.

Potentially toxic metals (PTMs) contamination in the soil poses a serious danger to people's health by direct or indirect exposure, and generally it occurs by consuming food grown in these soils. The present study assessed the pollution levels and risk to human health upon sustained exposure to PTM concentrations in the area's centuries-old glass industry clusters of the city of Firozabad, Uttar Pradesh, India. Soil sampling (0-15cm) was done in farmers' fields within a 1km radius of six industrial clusters. Various environmental (geo-accumulation index, contamination factor, pollution load index, enrichment factor, and ecological risk index) and health risk indices (hazard quotient, carcinogenic risk) were computed to assess the extent of damage caused to the environment and the threat to human health. Results show that the mean concentrations of Cu (33mgkg-1), Zn (82.5mgkg-1), and Cr (15.3mgkg-1) were at safe levels, whereas the levels of Pb, Ni, and Cd exceeded their respective threshold limits. A majority of samples (88%) showed considerable ecological risk due to the co-contamination of these six PTMs. Health risk assessment indicated tolerable cancer and non-cancer risk in both adults and children for all PTMs, except Ni, where adults were exposed to potential threat of cancer. Pearson's correlation study revealed a significant positive correlation between all six metal pairs and conducting principal component analysis (PCA) confirmed the common source of metal pollution. The PC score ranked different sites from highest to lowest according to PTM loads that help to establish the location of the source. Hierarchical cluster analysis grouped different sites into the same cluster based on similarity in PTMs load, i.e., low, medium, and high.

Bees reflect better on their ecosystem health than their products.

Beehives constitute a source of environmental contaminants because forager bees explore their habitat and unintentionally accumulate them while foraging for food. Therefore, this review paper investigated different bee species and products from 55 countries to identify how they can help environmental biomonitoring by giving an overview of the past 11 years. Thereby is presented in this study the beehive's use as a bioindicator for metals, analytical techniques, data analysis, environmental compartments, common inorganic contaminants, reference thresholds for some metal concentrations in bees and honey, and other factors over more than 100 references. Most authors agree that the honey bee is a suitable bioindicator to assess toxic metal contamination, and among its products, propolis, pollen, and beeswax are more suited than honey. However, in some situations, when comparing bees with their products, bees are more efficient as potential environmental biomonitors. Some factors such as the colony location, floral sources, regional effects, and activities surrounding the apiary influence the bees, and the composition of their products is reflected by alterations in their chemical profile, making them suitable bioindicators.

Assessment of Metal Contamination in Oreochromis niloticus from Ekiti State’s Major Dams, Southwest, Nigeria and its Human Health Implications

Agricultural and domestic activities around dams in Nigeria involve the use of agrochemicals and insecticides to boost production and combat insect pests respectively. The study aimed to ascertain metals contents and assess the hazards associated with heavy metals in Oreochromis niloticus in three major dams in Ekiti State. Fish samples were collected for 24 months. Metal concentrations in fish samples were determined using spectrometry. The metals concentrations in the tissues were at lower concentrations compared to the maximum acceptable limits in food by Food and Agricultural Organization (FAO) and World Health Organization (WHO). Metals accumulation pattern revealed that the accumulation of the essential metals were higher than those of the non-essential metals in the fish tissues. There were significant seasonal variations in the concentrations of metal in fish tissues within the dam and among the dams. Significant relationships existed at P &lt; 0.05 or P &lt; 0.01 between some of the metals and the fish body weight and body length in the different dams while in others the relationships were not significant. Human health risk assessment showed no significant non-carcinogenic adverse health risk. Carcinogenic health assessment indicates that the utilization of the species as a protein source does not currently pose public health risk to consumers. However, the discovery of cadmium and lead in fish muscle is of great concern because of their toxic effects on human. Therefore, there is a need for close monitoring of these toxic metals contamination to prevent their excessive accumulation in the human food chain.

Does Industrial Wastewater Irrigation Cause Potentially Toxic Metal Contamination and Risk to Human Health? Sugar Industry Wastewater and Radish Examples.

The goal of this study was to appraise potentially toxic metal contents in the soil-radish system in industrial wastewater irrigated areas. The analysis of metals in water, soil and radish samples were performed with spectrophotometric method. The potentially toxic metal values in the wastewater irrigated radish samples were ranged from 1.25 to 1.41, 0.02 to 0.10, 0.77 to 0.81, 0.72 to 0.80, 0.92 to 1.19, 0.69 to 0.78, 0.08 to 0.11, 1.64 to 1.67 and 0.49 to 0.63mg/kg for Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn and Mn, respectively. The potentially toxic metal values in the soil and radish samples irrigated with wastewater were lower than the maximum allowable limits, except for Cd. The results of the Health Risk Index evaluation conducted in this study also showed that the accumulations of Co, Cu, Fe, Mn, Cr, and Zn, especially Cd, pose a health risk in terms of consumption.

Genotoxicity Assessment and Toxic Metal Contamination of Traditionally used Anthelmintic Medicinal Plants in Assam, India

Medicinal plants possess several metals obtained naturally or through pollution. The study evaluates the genotoxic potentials and the presence of essential elements and toxic metals in Sesbania sesban var. bicolor (leaves), Cyperus compressus (roots), and Asparagus racemosus (roots), which are used as anthelmintics in the traditional medicine of the Santhals in India. A genotoxicity study was performed in rats as per Organization for Economic Co-operation and Development guidelines. Element contents were evaluated using inductively coupled plasma-optical emission spectrometry. Administration of S. sesban var. bicolor (400 mg/kg), C. compressus (700 mg/kg) and A. racemosus (500 mg/kg) did not cause any abnormalities in the chromosomes. Elemental analysis revealed the presence of lead (5.00±0.05, 4.98±0.01, 4.99±0.07 ppm), cadmium (4.99±0.04, 4.90±0.03, 5.00±0.08 ppm) and arsenic (0.98±0.03, 0.41±0.05, 0.92±0.03 ppm), respectively. Although their genotoxic potential was lacking, the presence of toxic metals in them is a cause for concern.

Evaluation of sediment dredging in remediating toxic metal contamination - a systematic review.

Toxic metal pollution is a leading environmental concern for aquatic systems globally, and remedial dredging has been widely employed to mitigate its harmful impacts. In terms of the short-term impacts of remedial dredging, mixed results are reported in several studies. Despite its immediate negative impacts including saturation of water with toxic metals, increased turbidity, and sediment resuspension, positive impacts can be recorded over a stabilization period of 6-24months after dredging. Nevertheless, the sustainability of these recorded positive effects cannot be ascertained as some studies have reported long-term regression in remediated sites' conditions. Evaluation of success determinants, site-measure compatibility, and determination of supplementary measures are keys to achieving and sustaining the projected benefits of remedial dredging and justifying its overall cost. This multicomponent study reviewed published literatures that documented the outcomes of short- and long-term dredging projects in toxic metal-polluted systems globally with a broad goal of examining how sediment removal impacts toxic metal dynamics in the aquatic system and understanding why the sustenance of positive impacts is controversial. In the meantime, this study also explored the preventative and remedial management strategies for attaining and sustaining positive dredging outcomes. The purpose of this study is to provide key recommendations for decision-making and policy development in aquatic toxic metal remediation.