Soil Heavy Metal Concentrations Research Articles

Assessment of heavy metal accumulation and health risks in okra (Abelmoschus Esculentus L.) and spinach (Spinacia Oleracea L.) fertigated with wastwater

In many countries like Pakistan, where crops are irrigated by wastewater, the accumulation of heavy metals is a serious problem, especially when such an irrigation is a widespread practice. The focus of this study was to know the highly toxic metals like cadmium (Cd), chromium (Cr), and lead (Pb) in water, agricultural soil, and crops, besides their probable risk to human health in the area of Vehari district. The physicochemical parameters were determined for the samples, including organic matter, organic carbon, pH, and electrical conductivity. Water used for irrigation, samples of vegetables for Cd, Cr, and Pb concentration, as well as transfer factor from soil to plants (TF) were analyzed for calculating the daily intake of metals (DIM) and their health risk index (HRI). The results show that the wastewater used for irrigation was contaminated with Cr (0.07mg/kg), Cd (0.054mg/kg), and Pb (0.38mg/kg). In the tube well, the concentrations of heavy metals were: Cd (0.053mg/kg), Pb (0.01mg/kg), and Cd (0.03mg/kg). Application of wastewater increased heavy metals concentration in soil and vegetables. Heavy metals concentrations in wastewater irrigated soil before sowing vegetables in mg/kg were: Pb (0.91), Cd (0.12), and Cr (0.48). After the application of wastewater, significant enrichment of wastewater was observed in Pb (1.93mg/kg), Cd (0.07mg/kg), and Cr (0.34mg/kg). Our study showed a high-risk index of food crops polluted with heavy metals and resultantly greater health risk to humans and animals. That is why preventive measures should be adopted to reduce heavy metals pollution to irrigation water and soils to protect both humans and animals in the Vehari district.

Comparative Analysis of Heavy Metals Concentration in Soil and Vegetable (Celosia argentea) Collected from Two Sampling Sites and Their Effect on the Plant’s DNA Stability

This study investigated the quantities of heavy metals including cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn)in soil samples and in the organs (leaf, stem and root) of Celosia argentea collected from a dumpsite (at Ojota) and a farmland (at Badagry) in Lagos, Nigeria. Additionally, the macroelement content of the soils and the effect of heavy metal soil contamination on C. argentea DNA stability was analysed. Heavy metals and NPK concentrations in the soil samples and organs of C. argentea were evaluated using standard techniques. The results of this study revealed that the microelement were more abundant in the soil collected from the dumpsite. Likewise, all the heavy metals (Cd,Cr,Cu,Pb and Zn) investigated in this study were detected in higher quantities in the dumpsite soil. Notably, the concentration of the metals was within the WHO/FAO limits in the soils collected from both sampling sites save Zn which was 660.260 mg/kg and 449.180mg/kg in the dumpsite and farmland respectively. The concentration of heavy metals in the C. argentea organs in this research were higher in samples collected from the dumpsite and Zn was the most accumulated on both the dumpsite and farmland. The highest amount (95.987 mg/kg) of Zn was by C. argentea root collected from the dumpsite while the least amount (15.380 mg/kg) was detected in C. argentea stem collected from the farmland. The DNA base pairs were not visibly fragmented in the samples C. argentea collected from the control and dumpsite sites. Although most of the heavy metals detected in C. argentea were in negligible quantities, the soils and the vegetable appear to be Zn-contaminated and unsafe for consumption. Keywords: Heavy Metal, DNA, vegetables, biomagnifications, Bioaccumulation, Dumpsites Farmlands

Heavy metal pollution in agricultural soils of a typical volcanic area: Risk assessment and source appointment.

Heavy metals are naturally occurring elements with high natural background levels in the volcanic area. Therefore, it is necessary to conduct a risk assessment and identify potential sources of heavy metals. In this study, 4488 soil samples (0-20cm) were collected in Chengmai County, a typical volcanic area in Hainan Province, and analyzed for eight heavy metals and major oxides. Pollution level, ecological risks, and health risks were evaluated by geo-accumulation index (Igeo), pollution index (PI), potential ecological risk index (RI), hazard index (HI), and carcinogenic risks (CR). The positive matrix factorization (PMF) model was further used to determine the priority source of heavy metals. The average values of heavy metal concentrations in soil were 7.06, 0.07, 156.88, 33.43, 0.05, 72.47, 19.48, and 67.51mgkg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. Except for Pb, the average concentrations of all heavy metals exceeded background concentration in Hainan soils, indicating different degrees of heavy metal enrichment. The Igeo and PI showed that the main pollutant element in volcanic soils was Ni, followed by Cr and Cu. The RI shows that the percentage of soil samples with considerable or worse potential ecological risk was 44.4% of the total samples, with Hg, As, Cd, and Ni causing high ecological risks. The estimated average daily doses of heavy metals were below the tolerable limits and the HI values were below one for both adults and children, indicating that the residents had an acceptable potential non-carcinogenic risk. However, the potential carcinogenic risk of exposure to Cr, Ni, and As was unacceptable for residents, with high CR values exceeding 10-4, especially for children. Based on the PMF, five major sources of heavy metals were found in the study area: Ni, Cu, and Zn mainly from parent materials, As and Pb from daily life and vehicle emissions, Cd from agricultural activities, Hg from industrial activities, and Cr from parent materials under different environmental conditions. Significant positive correlations between Al2O3, TFe2O3, Mn, soil organic carbon (SOC), and heavy metals reflect that aluminium-rich minerals, Fe-Mn oxides, and SOC are the most critical factors affecting heavy metal accumulation in volcanic agricultural soils.

Uptake of lead and zinc from soil by blackberry plants (Rubus fruticosus L. agg.) and translocation from roots to leaves

• Pb and Zn in soil ofa the Innerste floodplain exceed precautionary limits. • Concentrations of Pb and Zn in soils and blackberries are positively correlated. • Uptake and translocation of Pb and Zn are reduced at higher soil levels. • R. fruticosus is a useful bioindicator but unsuited for phytoremediation. Heavy metals transported by rivers are deposited in sediments and floodplains, and floodplain soils act as both sinks and sources of these metals. The Innerste River is contaminated by historical metal ore mining, processing, and smelting in the Harz Mountains (Germany). Our study compared the uptake of lead (Pb) and zinc (Zn) in wild blackberries ( Rubus fruticosus L. agg.) growing within and outside the Innerste floodplain in a downstream area. The potential of blackberries as bioindicators and for phytoremediation of soils polluted by Pb and Zn was assessed based on bioconcentration factors (BCF) and the intra-plant mobility of the two metals based on translocation (TF) factors. Concentrations of Pb and Zn were significantly higher in soils and blackberry plants from the Innerste floodplain compared to adjacent non-flooded area, while soil pH and organic matter content did not differ significantly between the two zones. Mean concentrations (mg/kg d.w.) of Pb (1457.2) and Zn (1365.2) in the regularly flooded soils far exceeded the precautionary limits of the German Federal Soil Protection and Contaminated Sites Ordinance. Concentrations of both heavy metals in blackberry roots and leaves increased with their levels in soil. Except for BCF Root Pb, BCFs and TFs decreased exponentially with increasing heavy metal concentration in soil and roots, respectively. This indicates that the uptake of Pb and Zn by R. fruticosus and their translocation within the plant are reduced at higher soil levels of both heavy metals. BCF < 1 were determined for both heavy metals and a TF < 1 for Pb. Only blackberries growing outside the floodplain showed a TF > 1 for Zn. Our results indicate that blackberries can be used as bioindicators of soil contamination by Pb and Zn. Regarding their uptake characteristics, blackberries constitute excluders rather than accumulators, and are thus unsuited for phytoremediation.

Estimating the heavy metal contents in farmland soil from hyperspectral images based on Stacked AdaBoost ensemble learning

• Assessment of heavy metal pollution in soil base on hyperspectral image. • Estimating the soil heavy metal content by constructing ensemble learning model. • The estimation accuracy of heavy metal content in soil is improved. • Mapping the distribution trend of heavy metals in farmland soil. • The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Heavy metal pollution poses a huge challenge to the soil environment. With the increasing pollution level, the traditional monitoring methods cannot quickly obtain information on large-area pollution. Therefore, a large-scale mapping method with high precision is urgently needed to effectively control heavy metal pollution. This study explored a method for mapping soil heavy metal concentrations through hyperspectral images. On this basis, a new Stacked AdaBoost ensemble learning algorithm was constructed to construct the inversion model of soil heavy metal contents. The characteristic spectral bands of heavy metals were extracted as model input variables using Pearson’s correlation coefficient and successive projections algorithm. With three sets of heavy metal content data, the prediction accuracy and mapping outcomes of various machine learning methods were compared. Furthermore, the potential sources of heavy metal pollution in the study area were analyzed based on the Moran’s index. The results showed that the Stacked AdaBoost model was relatively stable with higher accuracy than traditional machine learning models. For Cr, Cu, and As, the determination coefficients ( R 2 ) of the verification set were 0.66, 0.61, and 0.74, respectively. Afterward, the results of this model were used to map the heavy metal concentration over the study area. The mapping results suggested that the heavy metal conditions of soils in the Ganhetan area were caused by nature and human activities. The As pollution in agricultural soils was the most serious, with an exceedance rate of 38.66%. Industrial areas were potential sources of soil heavy metal pollution in the study area. In summary, the Stacked AdaBoost ensemble learning model provides detailed and reliable data for agricultural ecological protection and industrial pollution control, allowing the effective management of heavy metal pollution sources.

Contamination Evaluation and Source Analysis of Heavy Metals in Karst Soil Using UNMIX Model and Pb-Cd Isotopes.

Karst terrain is the typical area covered with a high background of heavy metals under geochemical anomaly. This research explored the accumulation of geochemical elements and soil sources in karst terrain from rock and soil exposed in carbonate areas. The comprehensive ecological risk and enrichment of heavy metals from parent rock weathered to soil was investigated in 11 formations in the carbonate and clastic areas of the Weining and Hezhang counties in northwest Guizhou. The single factor pollution index, geoaccumulation index, and the potential risk coefficient were used to assess the environmental risk. The results revealed that the heavy metals in an overall geologically high background level of soil in northwest Guizhou is at a slight risk level. However, except for Cd, the heavy metals did not exceed the standard pollution reference. Moreover, the UNMIX model and Cd and Pb isotopes were used to analyze the source of heavy metals, comprising of cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn), and the geochemical elements of silicon (Si), aluminum (Al), iron (Fe), magnesium (Mg), and calcium (Ca). The study showed that most elements in the soil carbonate area exceed the national standard, and the heavy metals in the soil showed a strong enrichment, while the major elements Si and Mg display strong loss. Heavy metal concentrations in soil in the carbonate area were higher than in the clastic area. Geological sources and atmospheric deposition were the main contributors to heavy metal concentrations in both carbonate and clastic areas, and their concentrations differ according to soils developing in different formations.

Comparative analysis of heavy metals concentration in soil and vegetable (Solanum lycopersicum) collected from two sampling sites (Farmland and Dumpsite) and the effect on plant DNA

Comparative analysis of heavy metals concentration in soil and vegetable (Solanum lycopersicum) collected from two sampling sites (Farmland and Dumpsite) and the effect on plant DNA

Comparative analysis of heavy metals concentration in soil and vegetable (Solanum lycopersicum) collected from two sampling sites (Farmland and Dumpsite) and the effect on plant DNA

One of the most popular crops with a unique role in human diets especially in Nigeria is Solanum Lycopersicum. The study investigated the levels of heavy metals (cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb)and zinc(Zn) and nutrients(nitrogen (N), phosphorus(P) and potassium(K) in the leaf, stem and root of Solanum lycopersicum and soil collected from dumpsite (in Ojota) and Farmland (in Badagry) in Lagos, Nigeria and their effects on S. lycopersicum using DNA analysis. The results recorded in mg/100g showed that only the value of Zn in stem of S. lycopersicum from farmland (77.671 ± 2.193) was significantly higher than that of dumpsite (72.169 ± 1.656) while Zn in the root S. lycopersicum from farmland (66.556 ± 0.613) was significantly lower than that of dumpsite (71.760±2.699). The values of K in the stem and root, P in the leaf, and N in the stem and root were higher in samples from farmland, while samples from dumpsite had higher value of N in leaf, P in stem and root and K in leaf. Only, Zn in the soil was significantly higher (p&lt;0.05) at dumpsite than farmland. The values of N, P and K in soil from dumpsite were higher (p&lt;0.05) than that from farmland. The DNA bands of the Solanum lycopersicum from control site and dumpsite site have no alteration. In conclusion, all the metal levels did not exceed World Health Organization limits and thus S. lycopersicum is safe for human consumption.

An Indirect Inversion Scheme for Retrieving Toxic Metal Concentrations Using Ground-Based Spectral Data in a Reclamation Coal Mine, China

A reclamation coal mine in Baishui County of Shaanxi Province, China, was selected as the study area to develop a fast survey method for estimating soil heavy metal concentrations using spectral data. A portable object spectrometer manufactured by Analytical Spectral Devices (ASD) was used to measure soil spectral reflectance, and an X-ray fluorescence device was utilized to obtain the content of heavy metals. The Savitzky-Golay filter, first derivative reflectance (FDR), second derivative reflectance (SDR), continuum removal (CR), and continuous wavelet transform (CWT) were used to transform the original reflectance (OR) spectra for enhancing the spectral characteristics, respectively. Furthermore, correlation analysis was introduced to determine the characteristic bands and the correlations of heavy metals. Partial least squares regression (PLSR), extremely learning machine (ELM), random forest (RF), and support vector machine (SVM) were implemented for quantitatively determining relations between heavy metal contents and spectral reflectance. The outcomes demonstrated that the spectral transformation methods could effectively capture the characteristic bands and increase the relations between heavy metal contents and spectral reflectance. The relation between Fe and Ni was close with a relatively high correlation coefficient (r = 0.741). RF combined with CWT at the decomposition scales of 9 demonstrated the best performance with the highest Rv2 (0.71) and the lowest RMSEv (1019.1 mg/kg) for inferring Fe content. Ni content was inferred based on the close relationship between Fe and Ni. The result of RF was better than other methods with the highest Rv2 (0.69) and the lowest RMSEv (1.94 mg/kg) for estimating Ni concentration. Therefore, the RF model was chosen for mapping Fe and Ni contents in the study area. The present study revealed that the indirect inversion methods using spectral data can be effectively used to predict heavy metal concentrations. The outcomes supply a new perspective for retrieving heavy metal content based on hyperspectral remotely sensed technology.

Soil heterogeneity influence on the distribution of heavy metals in soil during acid rain infiltration: Experimental and numerical modeling

Acid rain is a global environmental problem that mobilizes heavy metals in soils, while the distribution and geochemical fraction of heavy metals during acid rain infiltration in heterogeneous soils are still unclear. In this study, we performed column experiments to investigate the distribution and geochemical fraction of Cu, Pb, Ni and Cd in heterogeneously layered soils during continuous acid rain infiltration. Chloride ion used as a conservative tracer was found to be uniformly distributed during acid rain infiltration, showing insignificant preferential flow effects in the column. In contrast, however, the distribution of heavy metals was highly non-uniform, especially in the silty soil at the lower part of the column, indicating a heterogeneous distribution of adsorption capacity. In addition, in the control experiments with neutral rain infiltration, uniform distribution of heavy metals was observed, indicating that the heterogeneous distribution of adsorption coefficient during acid rain infiltration was mainly caused by different pH buffering capacities. A numerical model considering water flow and solute transport was developed, where the average water-solid distribution coefficient (Kd) in Layer 2 was only 1.5–12.5% of that in Layer 1 during acid rain infiltration. The model could predict the variation of heavy metal concentrations in soil with the majority of error less than 35%, confirming that different Kd induced the heterogeneous distribution of heavy metals. In addition, the geochemical fraction of heavy metals in the upper coarse sand layer remained stable, while the acid-extractable fractions in the lower loam and silt loam layer gradually increased. Our findings suggest that soil heterogeneity, especially chemical heterogeneity affected by rainfall acidity, has an important influence on the infiltration, migration and geochemical fraction of heavy metals in soils. This study could help guide the risk assessment of heavy metal-contaminated sites that were polluted by acid rain or landfill leachate.

Comparative Analysis of Heavy Metals Concentration in Soil and Vegetable (Capsicum annum) Collected from Two Sampling Sites (Farmland and Dumpsite) and the Effect on Plant DNA

The levels of heavy metals and their effect on the DNA of Capsicum annuum collected from dumpsite (in Ojota) and farmland (in Badagry) in Lagos, Nigeria, were examined using standard procedures.&#x0D; The results of concentration of heavy metals in the soil for the farmland and dumpsite respectively are: Zn (882.0 ±0.006mg/kg, 14316.8±1.009mg/kg), Cr (2.006 ±0.002mg/kg,3.888± 0.002mg/kg), Cd (0.098 ± 0.001mg/kg, 0.644 ± 0.002mg/kg), Cu (0.206± 0.001mg/kg, 0.997 ± 0.001mg/kg) and Pb (0.005 ± 0.003mg/kg, 0.843± 0.002mg/kg) respectively. The values of N (3153.6± 0.008mg/kg, 4191.2± 0.006mg/kg), P (7598.3 ± 0.009mg/kg, 8794.5 ± 0.003mg/kg) and K (113.56 ± 0.004mg/kg, 532.12 ± 0.004mg/kg) were recorded in the soil from farmland and dumpsite respectively. While the values of N, P, and K in soil from dumpsite were higher (p&lt;0.05) than that from farmland, the only value of Zn in the soil of dumpsite was significantly higher than in soil from farmland. Similarly, the values of all metals except Zn recorded in the leaf, stem, and root of C. annuum showed no significant difference between the sample collected from dumpsites and farmland. The values of Zn in leaf, stem, and root of C. annuum from farmland were significantly higher (p&lt;0.05) than that of the dumpsite. The DNA bands of the Capsicum annuum from the control site have a clearer band spectrum than that from the dumpsite site, however, there was no DNA mutation. In conclusion, C. annuum collected from both farmland (in Badagry) and dumpsite (in Ojota) contained minerals and heavy metals whose concentrations were still within standard permissible limits. Thus, C. annuum from both sites is safe for human consumption.

Pollution Levels and Risk Assessment of Heavy Metals in the Soil of a Landfill Site: A Case Study in Lhasa, Tibet.

As an important ecological security barrier in China, the ecological environment of Tibet has aroused widespread concern domestically and overseas. Landfills are a major solid waste treatment approach in Tibet but also cause severe environmental pollution. To date, there are no studies related to the pollution risk of landfills in Tibetan areas. This study investigated the pollution levels, ecological risk, health risk, and possible pollution sources of eight heavy metals in the soils around a landfill site in Lhasa, Tibet. The results indicated that the concentrations of heavy metals in soil were relatively low, only cadmium (Cd), arsenic (As), copper (Cu), chromium (Cr), zinc (Zn), nickel (Ni), and lead (Pb) were 1–2 times higher than the corresponding background value. The values of the single pollution index and geo-accumulation index show that the study area is most seriously polluted by Cd and As. Based on the Nemerow pollution index and the pollution load index, over 83.3% and 8.33% of soil sampling sites had light and moderate contamination levels. According to the results of potential ecological risk evaluation, the potential ecological risk of heavy metals in soil was very low, and only one out of the 72 sampling sites exhibited considerable ecological risk. Cd, As, and mercury (Hg) served as the dominant ecological risk contributors and contributed over 45.0%, 14.1%, and 18% of the ecological risk. The results of the health risk evaluation showed that adults have a higher risk of cancer (1.73 × 10−5), while the non-carcinogenic risk for adults was low. Waste disposal activities and construction activities have a significant influence on soil heavy metal concentrations, causing a higher pollution level in the southeast part of the landfill site in Lhasa.

Assessment of Heavy Metal Concentration in Soil and Plant and Evaluation of Bioconcentration Factor at Loumbila Market Gardening Perimeters, Burkina Faso

Agricultural soil quality deterioration resulting from an increase in the level of heavy metals is becoming more and more pronounced, thus raising the question on the safety status of human health and the environment. Determination of heavy metal concentration in soils and plants from Loumbila market gardening (Burkina Faso), and calculation of bioconcentration factor were undertaken. The heavy metals such as copper (Cu), nickel (Ni), lead (Pb), chromium (Cr), cadmium (Cd) and zinc (Zn) were measured using an atomic absorption spectrometer, model PERKIN ELMER AANALYST 200.&#x0D; In the soil where the pepper was grown, the concentration of chromium was 175 mg/kg, which is higher than the concentration limit which is 150 mg/kg. Also the concentrations of lead in the soils of onion (118 mg/kg), green bean (118 mg/kg), carrot (178 mg/kg) and pepper (135 mg/kg) were above the limit which is 100 mg/kg. The concentrations of chromium in Onion leaves (3.72 mg/kg), onions (4.65 mg/kg), lettuce (4.89 mg/kg), green beans (5.89 mg/kg) and bell peppers (3.56 mg/kg) were concentrations above the limit established by the FAO/WHO, which is 2.3 mg/Kg. The concentrations of lead in carrot, onion leaf, onion, lettuce, green bean and bell pepper were above the limit proposed by FAO/WHO.&#x0D; The bioconcentration factors show that the onion leaf (0.731), onion (0.929), lettuce (0.876), green bean (0.987) and bell pepper (0.858) are the plants that accumulate zinc and the carrot (0.524) accumulates nickel. The bioaccumulation of the metals in the vegetable from Loumbila market gardening decreased in the order of onion &gt; lettuce &gt; green bean &gt; bell pepper &gt; onion leaves &gt; carrot.

Source Identification and Health Risk Assessment of Heavy Metals in Soil: A Case Study of Lintancang Plain, Northeast China.

To investigate the concentration, source, and potential health risk of soil heavy metals (V, Cr, Ni, Cu, Zn, Pb, Hg), this study determined the concentration of these seven metals in 37 soil samples from Linyi City, southeast of Shandong Province, China. The mean concentrations of the investigated heavy metals followed the sequence: Cr (76.2 mg/kg) > V (70.5 mg/kg) > Zn (70.1 mg/kg) > Ni (34.0 mg/kg) > Pb (31.4 mg/kg) > Cu (23.2 mg/kg) > Hg (1.7 mg/kg). The enrichment factor (EF) and geo-accumulation index (Igeo) indicated an extreme enrichment of Hg (EF > 10, Igeo > 4) within the study area, while a slight enrichment of other metals. According to the toxic risk index (TRI), Hg accounted for the strongest soil toxicity (TRI = 8.07, 64.3%). The risk assessment with hazard index (HI) suggested that the health risks of all metals were acceptable, and the HI of adults was generally lower compared with that of the children. In addition, two principal components (PC) calculated by principal component analysis (PCA) were used to identify the sources of these heavy metals, which were 57.73% for PC 1 (Pb, Cr, Zn, Ni, Hg, Cu and V) and 21.63% for PC 2 (Hg, Cu and V), respectively. Moreover, PC 1 was mainly controlled by anthropogenic inputs, while PC 2 was contributed to by natural sources. Combined with the correlation matrix, it was concluded that there were three different sources for all seven heavy metals.

Levels of Heavy Metals in the Soil of Illegal Open Dumpsites in Malaysia

This study aims to understand the soil impacts of illegal dumpsites in Malaysia through quantifying the heavy metals in the soil of two dumpsites, one receiving construction waste and the other receiving municipal solid waste. Five soil samples were collected from each dumpsite, and sampling was repeated in the second week to examine the temporal changes in the levels of heavy metals. All sampling was conducted in triplicates. The soil samples were sieved, dried, and digested with aqua regia at 70 °C, after which the digested mixtures were filtered. The filtrates were diluted and tested with an atomic absorption spectrophotometer for heavy metals. The soil heavy metal concentration ranges were as follows: Al (24.67-142.20 mg/kg), Cd (&lt; 0.01-0.083 mg/kg), Cu (0.10-14.99 mg/kg), Fe (11.20-241.77 mg/kg), Mn (0.09-22.60 mg/kg), Ni (0.02- 0.77 mg/kg), and Zn (0.14-35.03 mg/kg). All the heavy metals have been detected at all the sampling points except that the Cd levels at some sampling points were below the detection limit. The levels of heavy metals varied spatially and temporally, though higher Cd, Cu, Fe, Mn, Ni, and Zn were detected consistently at two sampling points of the dumpsite receiving municipal waste. This could be linked to the electrical and electronic waste at the dumpsite. The levels of heavy metals in the soil did not constitute soil contamination. However, it is important to control illegal dumping activities to reduce the associated health and safety concerns, such as infestation of vermin, fire, physical hazards, and odor.

Al and Fe Heavy Metal Concentrations in the Vegetative and Root Parts of Dicranopteris linearis, Nephrolepis bifurcata, Stenochlaena palustris and Acrostichum aureum Grew in Highly Weathered Soil

Phytoremediation is a plant function that degrades, eliminates, and inactivates potentially hazardous and toxic compounds in the polluted water, soil, and air. In phytoremediation mechanisms, phytodegrading enzymes break down the pollutants taken up by plants (phytodegradation). Additionally, the microorganisms found in the plant-related rhizosphere can also degrade the pollutants in the soil (rhizodegradation). The plants can extract the pollutants from the soil and accumulate them in their tissues (phytoextraction) or immobilise the contaminants in their root zone, remove the harmful compounds from the water and soil through transpiration into the atmosphere, and regulate the heavy metal pollutants across their root system (phytostabilisation). In this study, researchers characterised the development and aptitude of different fern species to remediate the heavy metal pollutants present in the highly weathered soil (i.e., laterite soil). For this purpose, soil samples from 3 different sites in Perak, Selangor and Johor were collected. The phytoremediation ability of 4 different fern species (i.e., Dicranopteris linearis, Nephrolepis bifurcata, Stenochlaena palustris and Acrostichum aureum) was determined to understand the pattern and distribution of heavy metal contamination in soil. The ICP-MS technique was utilised to determine the concentration of heavy metals. The results indicated the presence of a high concentration of heavy metal at many of these sites, while the concentration of Al and Fe ions varied. In addition, a significant difference (P<0.0001) in the concentration of heavy metals was discovered between fern species. All the interactions were detected using the Analysis of variance (ANOVA) technique. Phytoremediation is considered an alternative technique for reducing the heavy metal concentration in soil in light of various factors that lead to the accumulation of heavy metals. Furthermore, the remediation of numerous sites that are polluted with heavy metals, like landfills, is a cost-effective solution employing green technologies, like phytoremediation.

The relationship between heavy metals concentrations in soil and plant (Senna auriculata (L.) Roxb.) of the hills and roadsides in Tiruchirappalli, India

The relationship between heavy metal concentrations of soil and plant (Senna auriculata) in the hills and roadsides was studied. Atomic absorption spectroscopy was used for determination of metals such as lead (Pb), chromium (Cr), cadmium (Cd), zinc (Zn), copper (Cu), and iron (Fe) in the soil and plant (leaves and flowers) samples. The results showed that heavy metal concentrations in roadside soil and plant samples were much greater than that in hills. It is evident that concentration of a heavy metal in soil samples are considerably higher (p&lt;0.05) than that in plant samples. Pearson correlation analysis shows that Pb in leaves and flowers correlated well with that in soil, r &gt;0.93. Strong positive relationship exists between soil and plant for Cr content, (r≥0.97). Cadmium and Zn contents in leaves and flowers correlated significantly with Cd, and Zn in soil, all r&gt;0.97. The Cu concentration of leaves and flowers shows a positive correlation with Cu content in soil, all r≥0.93. The Fe concentration of both plant leaves and flowers is found significantly and positively correlated with soil Fe, r=0.99. Overall results reveal that all the heavy metals are significantly and positively associated with soil and plant, implying that increasing concentration of heavy metals in soil is likely to increase their concentrations in S. auriculata plant. SAARC J. Agric., 20(1): 121-130 (2022)

Legacy of war: Pedogenesis divergence and heavy metal contamination on the WWI front line a century after battle

AbstractIn Europe, the First World War left a legacy on the environment due to the extensive and intense use of artillery during this period. This study examined a small wooded area in the Pas‐de‐Calais region in France which was subject to considerably less intense fire than previously studied WWI battlefields. In a process named “bombturbation,” significant physical changes have occurred to the landscape subject to artillery fire, resulting in a divergent soil development in craters. Cratering led to higher organic matter and electrical conductivity values, but—unlike other studies—no significant difference in soil pH. Soil heavy metal concentrations did not differ within craters compared to the flat landscape. However, lead (Pb) and copper (Cu) enrichment was observed above the baseline values for the region. Despite the average concentrations of Cu and Pb being within legal limits for soils in the UK and European Union, it is likely that enrichment of Cu and Pb in the concentrations observed has caused detrimental ecotoxicological and human health effects.Highlights Few studies investigate the legacy of WWI on soil, particularly from low intensity fighting. WWI bomb craters alter soil development, resulting in changes to organic matter and salinity. Cu and Pb enrichment of soil from WWI may lead to ecotoxicological and human health impacts.

Pollution Assessment of Urban Land by Heavy Metals in the City of Vladimir

Heavy metals pollution analysis of urban land in the city of Vladimir was performed. Soil samples were evaluated for lead, zinc, copper, nickel, manganese, cobalt and chromium. Obtained indicators were compared with MAC and background values. Regularities were identified of study areas proximity to industrial enterprises and heavy metals concentration in soils. Coefficients of heavy metals accumulation in soils were calculated and priority metal pollutants with the highest accumulation coefficients were identified, namely lead, arsenic and zinc.

Research on the Regional Environmental Impact and Risk Assessment Affected by Mineral Resource Development: A Case Study of the Taojia River Watershed in Hunan

The mining and production of mineral resources can directly lead to soil and water pollution, posing a serious threat to human health. In this study, the Taojia River basin, a tributary of the Xiangjiang River, was selected as the study area. Based on the concentrations of heavy metals (As, Cd, Pb, and Zn) in 653 soil/substrate samples collected from 342 points in the study area in 2013 and 2021, the changes in soil heavy metal concentrations in the region were systematically analyzed to assess their environmental risks and impacts on regional environmental quality. The results showed that from 2013 to 2021, the As, Pb, and Zn pollution in regional soil, tailing sand, and surface water was reduced, while the Cd pollution increased. The average soil As, Pb, and Zn concentrations decreased from 3,750, 2,340, and 1,180 mg/kg to 457, 373, and 387mg/kg, respectively, while the Cd concentration increased from 0.11to 1.91 mg/kg; additionally, the overall distribution trend of heavy metal concentrations was high in the south, low in the north, and gradually decreased from upstream to downstream. The single evaluation index of heavy metal pollution risk showed that the percentages of medium to heavy pollution points in the soil As, Pb, and Zn were 84, 57, and 28%, respectively, in 2013, and this index decreased to 38, 37, and 25%, respectively, in 2021. The regional environmental quality was closely related to the intensity of mineral resource development. From 2000 to 2010, frequent mining development activities led to an increase in the area of construction land and a continuous decrease in the area of arable land, grassland, and vegetation cover in the region. During 2010–2020, the area of construction land decreased, and the vegetation coverage increased. The comprehensive evaluation index showed that the overall soil pollution risk in the watershed decreased, and the proportion of heavily polluted points decreased from 80 to 65%. It was shown by principal component analysis and factor analysis that mining development activities were the largest source of heavy metal pollution, in addition to mixed sources of tailings, solid waste, agriculture, and traffic emission sources. The results provide a scientific basis for the management and risk control of heavy metal pollution in the Taojia River basin.