Potential toxic metals (PTMs) contamination in agricultural soils and foodstuffs with associated source identification and model uncertainty

Distribution and bioaccumulation of trace elements in two Cyprinidae fish species in the Indus river, Pakistan, including the impact of hydraulic structure on macroinvertebrates' biodiversity

The concentration of trace elements (chromium, lead, zinc, copper, manganese, and iron) was determined in water, sediment and tissues of two Cyprinidae fish species - Labeo rohita and Tor putitora - collected from the eight sampling stations of Indus River in 2022 for four successive seasons (autumn, winter, spring, summer), and also study the present condition of macroinvertebrates after the construction of hydraulic structure. The obtained results of trace element concentrations in the Indus River were higher than the acceptable drinking water standards by WHO. The nitrate concentration ranges from 5.2 to 59.6 mg l-1, turbidity ranges from 3.00 to 63.9 NTU, total suspended solids and ammonium ions are below the detection limit (<0.05). In the liver, highest dry wt trace elements (μg/g) such as Cr (4.32), Pb (7.07), Zn (58.26), Cu (8.38), Mn (50.27), and Fe (83.9) for the Labeo rohita; and Tor Putitora has significantly greater accumulated concentration (Cr, Pb, Zn, Cu, Mn, Fe) in muscle and liver than did Labeo rohita species. Additionally, lower number of macroinvertebrates were recorded during the monsoonal season than pre-monsoon and post-monsoon. Local communities surrounded by polluted environments are more probably to consume more fish and expose them to higher concentrations of toxic trace elements (lead and copper). The findings also provide a basis for broader ecological management of the Indus River, which significantly influenced human beings and socioeconomic disasters, particularly in the local community.

Heavy Metals Accumulation in Vegetables and Its Consequences on Human Health in the Areas Influenced by Industrial Activities

The degradation of the environment due to numerous industrial practices has emerged as a major issue globally, particularly in a country like Bangladesh. The present study dispenses information about heavy metal (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) contamination in some frequently consumed vegetables, namely, ash pumpkin, potato, bitter gourd, buffalo spinach, snake gourd, and pointed gourd grown in an industrially prone location and their repercussion on consumers' health. Proton-induced X-ray emission (PIXE) technique was used as the major analytical tool to detect heavy metal concentrations. Mean concentration and the range of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in vegetables were detected (4.81 ± 2.79, 2.43-10.94), (497.57 ± 258.08, 181.24-886.67), (644.49 ± 298.40, 179.56-998.78), (38.88 ± 14.31, 18.88-60.12), (58.11 ± 12.58, 42.55-84.79), (137.24 ± 48.37, 71.99-208.98), (123.31 ± 63.62, 49.97-256.09), (8.09 ± 2.69, 4.29-14.94), and (4.16 ± 2.95, 1.22-9.98) mg/kg (dry weight basis), respectively. An extreme level of heavy metal contamination in vegetable samples was notified regarding the estimated metal pollution index (MPI) and Nemerow pollution index (P) value, which underpinned the health risk values. The estimated hazard index (HI) value stipulated high risk in all varieties of vegetables regardless of age group and cadmium (Cd) was found as the major contributor. Concerning the carcinogenic risk index (CR) for single elements, the value of Co, Ni, and Cr was approximated far above the USEPA threshold risk limit (CR>1E-04). Moreover, total carcinogenic risk (TCR) for all varieties of vegetables exceeded the safety threshold value for both the age group and children, in particular, were found most vulnerable. The outshot of the present study divulged associated health risks for the population group by the heavy metals via dietary intake of vegetables.

Heavy Metal(oid)s Contamination and Potential Ecological Risk Assessment in Agricultural Soils

Soil pollution caused by heavy metal(oid)s has generated great concern worldwide due to their toxicity, persistence, and bio-accumulation properties. To assess the baseline data, the heavy metal(oid)s, including manganese (Mn), iron (Fe), Cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), lead (Pb), mercury (Hg), chromium (Cr), and cadmium (Cd), were evaluated in surface soil samples collected from the farmlands of Grand Forks County, North Dakota. Samples were digested via acid mixture and analyzed via inductively coupled plasma mass spectrometry (ICP MS) analysis to assess the levels, ecological risks, and possible sources. The heavy metal(oid) median levels exhibited the following decreasing trend: Fe > Mn > Zn > Ni > Cr > Cu > Pb > Co > As > Cd > Hg. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) suggested the main lithogenic source for the studied metal(oid)s. Metal(oid) levels in the current investigation, except Mn, are lower than most of the guideline values set by international agencies. The contamination factor (Cf), geo accumulation index (Igeo) and enrichment factor (EF) showed considerable contamination, moderate contamination, and significant enrichment, respectively, for As and Cd on median value basis. Ecological risk factor (Er) results exhibited low ecological risk for all studied metal(oid)s except Cd, which showed considerable ecological risk. The potential ecological risk index (PERI) levels indicated low ecological risk to considerable risk. Overall, the results indicate the accumulation of As and Cd in the study area. The high nutrients of the soils potentially affect their accumulation in crops and impact on consumers' health. This drives the impetus for continued environmental monitoring programs.

Assessing heavy metal and physiochemical pollution load of Danro River and its management using floating bed remediation

River Danro in Garhwa (India) plays a vital role as a significant source of surface water and a crucial tributary of the North Koel River, ultimately joining the Ganga River Basin. Serving both urban-industrial and rural areas, the region faces challenges, including sand mining near Belchampa Ghat. This study aimed to assess physicochemical and heavy metals pollution at nine sampling locations, utilizing the Overall Index of Pollution (OIP), Nemerow Pollution Index (NPI), and Heavy Metal Pollution Index (HPI). OIP values indicated excellent surface water quality (0.71) in non-monsoon and slight pollution (6.28) in monsoon. NPI ranged from 0.10 to 1.74 in non-monsoon and from 0.22 (clean) to 27.15 (heavily polluted) in monsoon. HPI results suggested groundwater contamination, particularly by lead. Principal component analysis (PCA) and geospatial mapping showed similar outcomes, highlighting the influence of adjacent land use on water quality. Recognizing the significance of the Danro River in sustaining life, livelihoods, and economic growth, the study recommends implementing measures like floating bed remediation and regulatory actions for effective river management. The study acknowledges weaknesses in the current practical assessment methods for water contamination. These weaknesses make it difficult to put plans for cleaning up and controlling contamination into action. Because of this, future research on developing new in-place remediation techniques should focus on creating better ways to measure how effective the cleanup is.

Risk assessment and strontium isotopic tracing of potentially toxic metals in creek sediments around a uranium mine, China

The contamination of creek sediments near industrially nuclear dominated site presents significant environmental challenges, particularly in identifying and quantifying potentially toxic metal (loid)s (PTMs). This study aims to measure the extent of contamination and apportion related sources for nine PTMs in alpine creek sediments near a typical uranium tailing dam from China, including strontium (Sr), rubidium (Rb), manganese (Mn), lithium (Li), nickel (Ni), copper (Cu), vanadium (V), cadmium (Cd), zinc (Zn), using multivariate statistical approach and Sr isotopic compositions. The results show varying degrees of contamination in the sediments for some PTMs, i.e., Sr (16.1-39.6 mg/kg), Rb (171-675 mg/kg), Mn (224-2520 mg/kg), Li (11.6-78.8 mg/kg), Cd (0.31-1.38 mg/kg), and Zn (37.1-176 mg/kg). Multivariate statistical analyses indicate that Sr, Rb, Li, and Mn originated from the uranium tailing dam, while Cd and Zn were associated with abandoned agricultural activities, and Ni, Cu, and V were primarily linked to natural bedrock weathering. The Sr isotope fingerprint technique further suggests that 48.22-73.84% of Sr and associated PTMs in the sediments potentially derived from the uranium tailing dam. The combined use of multivariate statistical analysis and Sr isotopic fingerprint technique in alpine creek sediments enables more reliable insights into PTMs-induced pollution scenarios. The findings also offer unique perspectives for understanding and managing aqueous environments impacted by nuclear activities.

Nickel sources affect soil biological properties but do not affect sorghum growth

Nickel (Ni) is an essential element, but it can be phytotoxic in high concentration, which may be caused by high availability in soil solution. The objective of this study was to evaluate the effect of sources and doses of Ni applied to a dystrophic Red Latosol cultivated with sorghum on i) the availability of the metal in the soil; ii) the impact on biological and biochemical properties of the soil; iii) the absorption and distribution in sorghum plants; and iv) crop productivity. The experiment was carried out within a completely randomized design with two nickel sources [nickel(II) nitrate, Ni(NO3)2 and nickel(III) oxide, Ni2O3], three doses (35, 70, and 140 mg Ni kg-1 soil), plus controls without Ni, with 3 replications. The concentrations of Ni in the soil, soil microbial biomass (SMB), basal soil respiration (BSR), metabolic quotient (qCO2), fluorescein diacetate (FDA) hydrolysis, and urease activity were determined. The concentrations of Ni in the leaf diagnostic and in the plant (shoot, root, and grains) were also measured. In the soil, the concentrations of available Ni remained between 0.21 and 54.01 mg Ni kg-1. Ni2O3 contributed very little to the increase in available Ni. SMB and the FDA hydrolysis were not affected by the Ni source or Ni dose, but BSR and qCO2 had significant increase with Ni application rates, suggesting the soil microorganisms faced stress. Soil urease activity was affected by Ni dose but not by Ni source. The dose of Ni as Ni(NO3)2 decreased the metal concentration in the plant, while that of Ni2O3 increased it. Nickel source did not affect dry mass production of the plants, but grain yield was affected in a dose-dependent manner when Ni2O3 was the source of Ni.

A short overview of radioactivity measurement studies in Uzbekistan

Natural radioactivity is a public health issue that affects people all around the world. Environmental radioactivity accounts for approximately 87% of the radiation dose received by human beings. The primary external source of irradiation to the human body is gamma radiation emitted by naturally occurring radioisotopes such as 40K and radionuclides from the 232Th and 238U families, as well as their decay products, which exist at trace amounts in all ground formations. The establishment of baseline data for environmental radiological studies is of great importance for the assessment of environmental radiological levels in Uzbekistan and related studies on human health risks. The current study aimed to describe the research state of the art on natural radioactivity in Uzbekistan with emphasis on results obtained during the last 20 years. NaI (Tl) and High Purity Germanium HPGe detectors were employed in most conducted studies. The results showed that data for natural radionuclide activity were below international standards in all but a few areas. The research results of this paper can play a good guidance and reference role in the planning of such research in the future.

WITHDRAWN: Trace metals translocation from soil to plants: Health risk assessment via consumption of vegetables in the urban sprawl of a developing country

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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.

Potentially toxic metals in irrigation water, soil, and vegetables and their health risks using Monte Carlo models

Food safety has become a serious global concern because of the accumulation of potentially toxic metals (PTMs) in crops cultivated on contaminated agricultural soils. Amongst these toxic elements, arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) receive worldwide attention because of their ability to cause deleterious health effects. Thus, an assessment of these toxic metals in the soils, irrigation waters, and the most widely consumed vegetables in Nigeria; Spinach (Amaranthushybridus), and Cabbage (Brassica oleracea) was evaluated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentration (measured in mg kg-1) of the PTMs in the soils was in the sequence Cr (81.77) > Pb(19.91) > As(13.23) > Cd(3.25), exceeding the WHO recommended values in all cases. This contamination was corroborated by the pollution evaluation indices. The concentrations (measured in mg l-1) of the PTMs in the irrigation water followed a similar pattern i.e. Cr(1.87) > Pb(1.65) > As(0.85) > Cd(0.20). All the PTMs being studied, were found in the vegetables with Cr (5.37 and 5.88) having the highest concentration, followed by Pb (3.57 and 4.33), and As (1.09 and 1.67), while Cd (0.48 and 1.04) had the lowest concentration (all measured in mg kg-1) for cabbage and spinach, respectively. The concentration of the toxic metals was higher in spinach than in cabbage, which may be due to the redistribution of the greater proportion of the metals above the ground tissue, caused by the bioavailability of metals in the aqueous phase. Expectedly, the hazard index (HI),and carcinogenic risk values of spinach were higher than that of cabbage. This implies that spinach poses potentially higher health risks. Similarly, the Monte Carlo simulation results reveal that the 5th percentile, 95th percentile, and 50th percentile of the cumulative probability of cancer risks due to the consumption of these vegetables exceeds the acceptable range of 1.00E-6 and 1.00E-4. Thus, the probable risk of a cancerous effect is high, and necessary remedial actions are recommended.

Receptor model-based source-specific health risks of toxic metal(loid)s in coal basin-induced agricultural soil in northwest Bangladesh

Toxic metal(loid)s (TMLs) in agricultural soils cause detrimental effects on ecosystem and human health. Therefore, source-specific health risk apportionment is very crucial for the prevention and control of TMLs in agricultural soils. In this study, 149 surface soil samples were taken from a coal mining region in northwest Bangladesh and analyzed for 12 TMLs (Pb, Cd, Ni, Cr, Mn, Fe, Co, Zn, Cu, As, Se, and Hg). Positive matrix factorization (PMF) and absolute principal component score-multiple linear regression (APCS-MLR) receptor models were employed to quantify the pollution sources of soil TMLs. Both models identified five possible sources of pollution: agrochemical practice, industrial emissions, coal-power-plant, geogenic source, and atmospheric deposition, while the contribution rates of each source were calculated as 28.2%, 17.2%, 19.3%, 19% and 16.3% in APCS-MLR, 22.2%, 13.4%, 24.3%, 15.1% and 25.1% in PMF, respectively. Agrochemical practice was the major source of non-carcinogenic risk (NCR) (adults: 32.37%, children: 31.54%), while atmospheric deposition was the highest source of carcinogenic risk (CR) (adults: 48.83%, children: 50.11%). NCR and CR values for adults were slightly higher than for children. However, the trends in NCR and CR between children and adults were similar. As a result, among the sources of pollution, agrochemical practices and atmospheric deposition have been identified as the primary sources of soil TMLs, so prevention and control strategies should be applied primarily for these pollution sources in order to protect human health.

Ecological risk assessment and heavy metals accumulation in agriculture soils irrigated with treated wastewater effluent, river water, and well water combined with chemical fertilizers

Contaminated irrigation water can increase trace heavy metals concentration in agricultural soil. The present research aimed to investigate the effect of three types of irrigation water sources, including treated wastewater effluent, Gharasoo river water, and well water with chemical fertilizer, on the accumulation and ecological risk of heavy metals in agricultural soils. Soil samples were collected before and after crop irrigation to evaluate heavy metal concentrations. The samples were analyzed to determine the presence of arsenic, nickel, cadmium, iron, chromium, zinc, lead, copper, and manganese. Based on the results, the concentration of essential metals in the soil before the irrigation process was more than toxic metals. The different irrigation sources increased the concentration of all heavy metals in the soil, and the accumulation of Cr, Ni, and Cd significantly elevated more than others. Irrigation resources' effectiveness in transferring heavy metals to the soil was obtained as treated wastewater effluent < well water with fertilizer < river water. Furthermore, the potential ecological risk index (RI) for irrigated soil was in a high-risk category. Therefore, it is recommended that the river water should not be used to irrigate vegetables to the utmost possible. Finally, the low heavy metals concentration and the presence of nutrients in treated wastewater effluent make this source the most suited source of irrigation because it eliminates the need for chemical fertilizers by farmers and transfers fewer heavy metals to the soil.

Direct absorption of atmospheric lead by rapeseed siliques is the leading cause of seed lead pollution

Rapeseed cultivation is a novel approach to safely utilizing lead (Pb) contaminated farmland. However, the mechanism of Pb absorption in seeds remains uncertain. A field experiment was conducted to explore this mechanism with two contrasting treatments: rapeseed exposed to atmospheric deposition and non-exposed treatment. Non-exposed treatment ultimately decreased Pb content in leaf, silique, and seed by 46.7%, 53.7%, and 53.6%, respectively. Sub-microstructure analysis further confirmed that rapeseed leaves and siliques could directly absorb atmospheric Pb. In addition, Pb isotope analysis indicates that atmospheric deposition is the primary source of silique and seed Pb. The root and silique organs had relative Pb contributions of 28.0% and 72.0%, respectively, to seed. Thus, the direct absorption of atmospheric Pb by siliques during the filling stage was found to be the leading cause of seed Pb pollution.

Evaluating heavy metal pollution risks and enzyme activity in soils with intensive hazelnut cultivation under humid ecological conditions

In order to promote sustainable agriculture and ensure food security, it has become more vital to identify the causes of soil pollution in agricultural areas. This study was carried out in order to determine the danger of heavy metal contamination in hazelnut production areas and to take the appropriate actions in accordance with the study's findings. In this context, the main objectives of this study were to (i) determine some physical, chemical, and biological properties and heavy metal concentrations of different soils in intensive hazelnut cultivation areas under humid ecological conditions; (ii) reveal the heavy metal pollution risks of these areas by their enrichment factor, contamination factor, geo-accumulation index, degree of contamination, pollution load index, and potential ecological risk index; (iii) analyze the quality of soils contaminated with heavy metals by their total enzyme activity index and the geometric mean of enzymatic activities; and (iv) explore the correlation between heavy metals and soil enzyme activity indices. According to our results, the average concentrations of heavy metals in the study area ranked as Fe > Mn > Zn > Cr > Ni > Cu > Co > Pb > Cd. Based on EF, the area was evaluated as between deficiency to low enrichment and moderate enrichment for all elements except for Cd. When the parameters used to assess the risk of heavy metal contamination were evaluated, it was determined that the risk of contamination of other elements in the study area, except Cd, was low. Finally, analyzing the heavy metals and soil enzyme activity indices shows that there is a negative correlation between Ni and GMea and TEI.

Accumulation, environmental risk characteristics and associated driving mechanisms of potential toxicity elements in roadside soils across China

Roadside soils may be affected by potential toxicity elements (TPEs) from vehicles; however, pollution status, ecological and health risks of PTEs in roadside soils were rarely reported on national scale. In this study, a dataset of PTEs in roadside soils was compiled based on the literatures published in 2000-2021, and then pollution level, ecological and health risks of PTEs were evaluated using geochemical accumulation index (I_geo), potential ecological risk index (ER), and human risk assessment coupled with Monte Carlo simulation. Driving factors of PTE accumulation in soils were determined by Geo-detector method. Results indicated that Cd exhibited moderate pollution and considerable ecological risk with the highest I_geo of 1.25 and ER of 100.1, respectively. Vehicle ownership (VP) and precipitation (PP) significantly affected accumulation of PTEs, with q values of 0.209 and 0.191 (P < 0.05), respectively. VP paired with PP enhanced nonlinearly PTE accumulation (q = 0.77). Only 6.89% and 1.54% of non-carcinogenic risks for children and adolescent exceeded the threshold of 1, respectively, whereas 93.11%, 95.67%, 58.80% and 58.14% of carcinogenic risks for senior, adults, adolescent, and children surpassed 1E-06, respectively. The results of this study provided valuable implication for managers to design effective strategies for pollution prevent and risk control.

Detection of Bacillus Species with Arsenic Resistance and Plant Growth Promoting Efficacy from Agricultural Soils of Nepal

Arsenic contamination in soil and water is one of the major environmental problems in multiple countries including Nepal imposing a serious threat to the ecosystem and public health. Many soil bacteria can detoxify arsenic, including genus Bacillus. With an objective to gauge the plant growth-promoting activities of arsenic-resistant Bacillus species, 36 samples (soil, rice, cauliflower, and beans) were collected from the Terai region of Nepal. For selective isolation of Bacillus species, each sample was heated at 80°C for 15 min before the inoculation into nutrient agar (NA). Following the standard protocol, arsenic-resistant Bacillus species were screened using NA supplemented with 100 ppm sodium arsenate and sodium arsenite. Among 158 randomly selected isolates, only five isolates were able to tolerate sodium arsenite concentration up to 600 ppm. Notably, all five isolates were able to produce indole acetic acid (IAA), a plant hormone, and solubilize phosphate. Based on biochemical analysis and 16S rRNA gene sequencing, isolates N4-1, RW, KR7-12, Bhw1-4, and BW2-2 were identified as B. subtilis subsp. stercosis, B. flexus, B. licheniformis, B. cereus, and B. flexus, respectively. To the best of our knowledge, this is the first study showing the presence of arsenic-resistant B. flexus in Nepalese soil with plant growth-promoting traits. Possible utilization of these Bacillus strains could facilitate the novel bioremediation pathway to reduce the toxic effect of arsenic from the soil and water in the Terai region of Nepal.

Quantitative source apportionment and associated driving factor identification for soil potential toxicity elements via combining receptor models, SOM, and geo-detector method

Quantitative source apportionment of soil potential toxicity elements (PTEs) and associated driving factor identification are critical for prevention and control of soil PTEs. In this study, 421 soil samples from a typical area in southeastern Yunnan Province of China were collected to evaluate the pollution level of soil PTE using pollution factors, pollution load index, and enrichment factors. Positive matrix factorization (PMF), absolute principal component score/multiple line regression (APCS/MLR), edge analysis (UNMIX) and self-organizing map (SOM) were applied for source apportionment of soil PTEs. The geo-detector method (GDM) was used to identify the driving factor to PTE pollution sources, which assisted in source interpretation derived from receptor models. The results showed that the geometric mean of As, Cd, Cu, Cr, Ni, Pb, and Zn were 94.94, 1.02, 108.6, 75.40, 57.14, 160.2, and 200.3 mg/kg, which were significantly higher than their corresponding background values (P < 0.00). Particularly, As and Cd were 8.71 and 12.75 times higher than their corresponding background values, respectively. SOM yielded four clusters of soil PTEs: AsCd, PbZn, CrNi, and Cu. APCS/MLR was regarded as the preferred receptor model for source apportionment of soil PTEs due to its optimal performance. The results of ACPS/MLR revealed that 36.64% of Pb and 38.30% of Zn were related to traffic emissions, Cr (92.64%) and Ni (82.51%) to natural sources, As (85.83%) and Cd (87.04%) to industrial discharge, and Cu (42.78%) to agricultural activities. Distance to road, lithology, distance to industries, and land utilization were the respective major driving factor influencing these four sources, with the q values of 0.1213, 0.1032, 0.2295 and 0.1137, respectively. Additionally, GDM revealed that nonlinear interactions between anthropogenic and natural factors influencing PTEs sources. Based on these results, comprehensive prevention and control strategies should be considered for pollution prevention and risk controlling.

Impact of Industrially Affected Soil on Humans: A Soil-Human and Soil-Plant-Human Exposure Assessment

Heavy metal (HM) contaminated soil can affect human health via ingestion of foodstuffs, inhalation of soil dust, and skin contact of soil. This study estimates the level of some heavy metals in soils of industrial areas, and their exposures to human body via dietary intake of vegetables and other pathways. Mean concentrations of Cr, Fe, Cu, Zn, As and Pb in the studied soil were found to be 61.27, 27,274, 42.36, 9.77, 28.08 and 13.69 mg/kg, respectively, while in vegetables the respective values were 0.53, 119.59, 9.76, 7.14, 1.34 and 2.69 mg/kg. Multivariate statistical analysis revealed that Fe, Cu, Zn, and Pb originated from lithogenic sources, while Cr and As are derived from anthropogenic sources. A moderate enrichment was noted by Cr, As, and Pb in the entire sampling site, indicating a progressive depletion of soil quality. The bioaccumulation factor (BCF) value for all the vegetables was recorded as BCF < 1; however, the metal pollution index (MPI) stipulates moderately high value of heavy metal accumulation in the vegetable samples. Hazard Index (HI) of >0.1 was estimated for adults but >1 for children by direct soil exposure, whereas HI < 1 for both children and adults via dietary intake of vegetables. Estimated Total carcinogenic risk (TCR) value due to soil exposure showed safe for adults but unsafe for children, while both the population groups were found to be safe via food consumption. Children are found more vulnerable receptors than adults, and health risks (carcinogenic and non-carcinogenic) via direct soil exposure proved unsafe. Overall, this study can be used as a reference for similar types of studies to evaluate heavy metal contaminated soil impact on the population of Bangladesh and other countries as well.

Toxic metal pollution and ecological risk assessment in water and sediment at ship breaking sites in the Bay of Bengal Coast, Bangladesh

Quantification of four toxic metals (As, Cr, Cd, and Pb) in water and sediments at the Sitakunda ship breaking area in Bangladesh was studied. Along with this, sediment quality and ecological risk were evaluated for the metal intrusion to the study area. A total sample number of 120 (water; n = 60 and sediment; n = 60) were analyzed for both winter and summer seasons using atomic absorption spectrophotometer (AAS). The trace metal concentration in both water and sediment showed decreasing trend as follows; Cr (mean-W: 0.118 mg/L; mean-S:121.87 mg/kg) > Pb (mean-W: 0.064 mg/L; mean-S: 65.31 mg/kg) > As (mean-W: 0.03 mg/L; mean-S: 32.53 mg/kg) > Cd (mean-W: 0.004 mg/L; mean-S: 4.81 mg/kg). However, in both segments, the concentrations of the toxic metals exceeded the recommended acceptable limits. As and Cd showed significant variation (water and sediment) between the seasons, while Pb and Cr had no seasonal impact. Metal pollution index (MPI) and contamination factor (CF) was evaluated and revealed that the study area exhibited the critical score of water quality (MPI > 100). The cumulative effect of the metal concentrations was high (CI > 3). The assessed mean geoaccumulaiton index (I_geo) revealed that the study area was moderate to strongly polluted except for Cr. According to the contamination factor (CF), the sediment samples were moderate to highly contaminated by Cd, Pb, and As. Moreover, the explored range of pollution load index (PLI) in all sampling sites in the ship breaking region was from 1.75 to 3.10, suggesting that the sediment in the study area was highly polluted by heavy metals (PLI > 1). The risk index and the potential ecological risk index (PERI) suggested that the study area was at high risk due to metals pollution. Therefore, it is obligatory to maintain some crucial efforts for the betterment of the surrounding environment near the investigated sites.

Deposition of Potentially Toxic Metals in the Soil from Surrounding Cement Plants in a Karst Area of Southeastern Brazil

Cement factories are the main sources of environmental pollutants among the different industrial activities, including soil contamination by potentially toxic metals. The karst region of Southeastern Brazil is known for the implementation of large cement producing facilities. This study aims to evaluate whether there is an increase in the concentration of PTM in the soil surrounding the cement plants and to estimate their harmfulness to both local human population and environment. In total, 18 soil samples were collected from the surroundings of three cement plants as well as four soil samples from areas outside the influence of cement plants and concentration of the following potentially toxic metals (PTM) were estimated: Cd, Pb, Co, Cu, Cr, Mn, Ni, and Zn. The results revealed that all PTM concentrations from cement plant surroundings were significantly higher than PTM concentrations from control areas and no PTM concentrations from CPS or CA soil samples exceeded national and global contamination thresholds. However, Igeo Index indicated low level soil contamination by Pb, Cu, and Cr, as well as high levels for Co. We could not verify significant non-carcinogenic risk to health for any soil sample, but carcinogenic risk analysis revealed different levels of carcinogenic risk among the sampled locations, for both adults and children. Our results indicate that exclusively evaluating the concentration of potentially toxic metals is not enough to verify the potential harmful effects of cement production for the surrounding population. Here we evidence that additional indices, based on both contamination indices and health risk assessments, should be considered for better evaluation of the impacts of cement production activity.