Accumulation Of Metals In Soils Research Articles

Carcinogenic-potential ecological risk assessment of soils and wheat in the eastern region of Konya (Turkey).

The drainage channel where the wastewater of Konya city center is discharged, the solid waste storage center, the soils surrounding the industrial area, the potential accumulation of toxic elements (PTE) accumulated in the wheat grown in these soils, and their effects on human health were examined. Between 1977 and 2010, the water in the drainage channel was used for a variety of crops, mainly wheat grown in the nearby agricultural areas until the commissioning of the wastewater treatment plant. Industrial facilities, solid waste landfills, and military firing areas are actively used and are thought to be important factors in heavy metal accumulation in soils. In addition, the investigation area is on the sediments of the deposits stored in the large Konya Lake depending on the geological structure around Konya and caused geogenic heavy metal accumulation as a result of the separation and transportation of ophiolitic, magmatic, metamorphic, and sedimentary rocks in the region. In the research, PTE accumulation was determined in the samples of N1 (Pb, As, and Hg), N9 (Cd, As), and N10 (Cd and As) and N8 (Pb) in wheat. The carcinogenic risk factor of Ni, Al, Mn, and Cr elements in the territory of the region has been found as "medium" for children and adults. It has been determined that the potential source of toxic elements does not only depend on anthropogenic events but also occurs as a result of geological events.

Effect of sewage sludge application on heavy metals contamination in soil and carrot

One of the many environmental problems in the modern world is the disposal of production and consumption waste, including sewage sludge. The aim of our research was to study the content and accumulation of heavy metals in soil and carrots when using increasing doses of sewage sludge as fertilizer and its effect on the yield of products. Sewage sludge with a moisture content of 44.5% was introduced into gray forest soils. After fertilizing the soil, agrochemical analyzes of soil samples from the plots of the experimental plot for the content of heavy metals were carried out. We also studied the content of heavy metals in carrot biomass and its yield. It was found that the content of heavy metals in various variants of experiments with the use of sewage sludge increased. It was found that the dynamics of migration of heavy metals into the biomass of carrots correlates with an increase in their concentration in the soil and affects the yield of carrots.

Transfer of heavy metals in fruits and vegetables grown in greenhouse cultivation systems and their health risks in Northwest China

Due to the high cropping index and substantial agricultural inputs in greenhouse cultivation systems (GCS) compared to traditional farming methods, the environmental problems caused by heavy metals in GCS are becoming increasingly serious. The concentration of the heavy metals As, Cd, Cr, Cu, Pb and Zn in soil and food crops were analyzed and assessed in two study areas. There were greater accumulation of heavy metals in soils from Central Shaanxi (CS) than that from Northern Shaanxi (NS). However, heavy metal concentrations in leafy vegetables were higher in NS compared to CS, particularly Cr accumulation in leafy vegetables. Overall, leafy vegetables contained higher concentrations of heavy metals than fresh fruits and fruit vegetables from both areas. The heavy metal transfer factors (TF) for fresh fruits and fruit vegetables were as follows: Cu > Zn > Cd > Cr > As > Pb. However, in leafy vegetables, Cd had a higher TF value than the other metals tested. The target hazard quotient (THQ) values were less than 1 for fruits and vegetables, except for As in leafy vegetables from NS. The THQ values indicated that As contamination was the most serious concern, followed by Cu > Zn > Cd > Pb > Cr in both areas. The soil threshold value (STV) based on THQ showed that the level of As in leafy vegetables grown in alkaline soil was 10.85, which was inferior to the current standards. This study demonstrates the health risks associated with the heavy metal content of fruits and vegetables grown in GCS and suggests that necessary measures should be taken to reduce the accumulation of heavy metals in GCS crops in northwest China.

Contribution of GIS techniques and pollution indices in the assessment of metal pollution in agricultural soils irrigated with wastewater: case of the Day River, Beni Mellal (Morocco)

Wastewater irrigation and intensive agricultural practices are two of the major sources of soil pollution throughout the world. The aim of this study was to evaluate the levels of metal pollution in ground samples collected in the city of Beni Mellal, Morocco due to wastewater in the Day River. We collected 35 samples of agricultural soils at a sampling depth of 0–30 cm. As a first step, all samples were analyzed to determine some of the physicochemical characteristics of the soil samples (organic matter [OM], clay mineralogy [CaCO3], pH, electrical conductivity, texture) and the levels of specific metallic elements (As, Cr, Cu, Cd, Ni, Pb, Zn, and Fe). The results revealed that the analyzed soils had a clayey to silty-clay texture and alkaline pH; were rich in OM and carbonates; and had elevated levels of metallic elements (in mg/kg: As, 8.24; Cr, 77.77; Cu, 87.40; Cd, 4.89; Ni, 42.33; Pb, 109.66; Zn, 75.98; Fe: 26,248.18), all of which, with the exception of Ni, were higher than local background values. In addition, the concentrations of Pb and Cd considerably exceeded the limit values set by the World Health Organization and the Food and Agriculture Organization. To comprehensively assess the degree of pollution, we calculated a wide range of pollution indices, such as the geoaccumulation index (Igeo), enrichment factor (EF), contamination factors (CF), pollution load index (PLI), and potential ecological risk assessment (RI), using geochemical background values. The results showed that the levels of contamination in the soils under investigation ranged from moderate to high levels, suggesting an anthropogenic source. Analysis of the spatial distribution of the heavy metals showed high concentrations in the center and upstream part of Day River, with concentrations gradually decreasing downstream with the flow of wastewater. Statistical analyses were carried out to identify the relationship between the presence of heavy metals in the soils and the possible sources using principal component analysis and hierarchical clustering analysis methods and the Pearson correlation coefficient. The results of these analyses showed a significant and positive correlation between the presence of all heavy metals, indicating an identical or similar source, and also revealed that the contamination is related to the type of irrigation system, intensive agriculture practices, and soil properties (pH, OM, CaCO3). These results provide valuable geochemical data to support land-use managers, policy-makers, and environmental organizations in their efforts to monitor and decrease the accumulation of heavy metals in soils.

Assessing the Plant Growth Promoting and Arsenic Tolerance Potential of Bradyrhizobium japonicum CB1809.

Accumulation of heavy metals in soil is of concern to the agricultural production sector, because of the potential threat to food quality and quantity. Inoculation with plant growth-promoting bacteria (PGPR) has previously been shown to alleviate heavy metal stress but the mechanisms are unclear. Potential mechanisms by which inoculation with Bradyrhizobium japonicum CB1809 affected the legume soybean (Glycine max cv. Zeus) and the non-legume sunflower (Helianthus annus cv. Hyoleic 41) were investigated in solution culture under 5 μM As stress. Adding As resulted in As tissue concentrations of up to 5 mg kg-1 (shoots) and 250 mg kg-1 (roots) in both species but did not reduce shoot or root biomass. Inoculation increased root biomass but only in the legume (soybean) and only with As. Inoculation resulted in large (up to 100%) increases in siderophore concentration but relatively small changes (±10-15%) in auxin concentration in the rhizosphere. However, the increase in siderophore concentration in the rhizosphere did not result in the expected increases in tissue N or Fe, especially in soybean, suggesting that their function was different. In conclusion, siderophores and auxins may be some of the mechanisms by which both soybean and sunflower maintained plant growth in As-contaminated media.

Adsorption of Heavy Metals on Soil Collected from Lixisol of Typical Karst Areas in the Presence of CaCO3 and Soil Clay and Their Competition Behavior

The content of heavy metals in the soil in Guizhou Province, which is a high-risk area for heavy metal exposure, is significantly higher than that in other areas in China. Therefore, the objective of this study was to evaluate the ability of CaCO3 and clay to accumulate heavy metals in topsoil sample collected from Lixisol using the method of indoor simulation. The results showed that the contents of Cu, Zn, Cd, Cr, Pb, Hg and As in the soil sample were 10.8 mg/kg, 125 mg/kg, 0.489 mg/kg, 23.5 mg/kg, 22.7 mg/kg, 58.3 mg/kg and 45.4 mg/kg, respectively. The soil pH values increased with the CaCO3 concentration in the soil, and the fluctuation of the soil pH values was weak after the CaCO3 concentrations reached 100 g/kg. The adsorption capacity of lime soil increased by approximately 10 mg/kg on average, and the desorption capacity decreased by approximately 300 mg/kg on average. The desorption of all heavy metals in this study did not change with increasing clay content. Pseudo-second-order kinetics were more suitable for describing the adsorption kinetics of heavy metals on the soil material, as evidenced by the higher R2 value. The Freundlich model can better describe the adsorption process of As on lime soil. The process of As, Cr, Cd and Hg adsorption on the soil sample was spontaneous and entropy-driven. Additionally, the process of Cu and Pb adsorption on the soil materials was spontaneous and enthalpy-driven. Generally, the adsorption and desorption of heavy metals in polluted soil increased and decreased, respectively, with increasing CaCO3 content. The effect of calcium carbonate on the accumulation of heavy metals in soil was greater than that of clay. In summary, CaCO3 and pH values in soil can be appropriately added in several areas polluted by heavy metals to enhance the crop yield and reduce the adsorption of heavy metals in soils.

A critical analysis of wastewater use in agriculture and associated health risks in Pakistan.

Freshwater shortage and its contamination with various types of pollutants are becoming the most alarming issues worldwide due to impacts on socioeconomic values. Considering an increasing freshwater scarcity, it is imperative for the growers, particularly in semiarid and arid areas, to use wastewater for crop production. Wastewaters generally contain numerous essential inorganic and organic nutrients which are considered necessary for plant metabolism. Besides, this practice provokes various hygienic, ecological and health concerns due to the occurrence of toxic substances such as heavy metals. Pakistan nowadays faces a severe freshwater scarcity. Consequently, untreated wastewater is used routinely in the agriculture sector. In this review, we have highlighted the negative and positive affectivity of wastewater on the chemical characteristics of the soil. This review critically delineates toxic metal accumulation in soil and their possible soil-plant-human transfer. We have also estimated and deliberated possible health hazards linked with the utilization of untreated city waste effluents for the cultivation of food/vegetable crops. Moreover, we carried out a multivariate analysis of data (144 studies of wastewater crop irrigation in Pakistan) to trace out common trends in published data. We have also compared the limit values of toxic metals in irrigation water, soil and plants. Furthermore, some viable solutions and future viewpoints are anticipated taking into account the on-ground situation in Pakistan-such as planning and sanitary matters, remedial/management technologies, awareness among local habitants (especially farmers) and the role of the government, NGOs and pertinent stakeholders. The data are supported by 13 tables and 7 figures.

Influence of iron mining activity on heavy metal contamination in the sediments of the Aqyazi River, Iran.

In order to investigate the degree of contamination of heavy metals (As, Cd, Cr, Cu, Fe, Pb, and Ni) in the Aqyazi River in Iran, sediment samples were collected from the river receiving wastewater from an iron-manufacturing plant. For this study, contamination indices, geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI), were used to assess contamination by the heavy metals. The results of the Igeo indicated that the sediments were moderately contaminated by Cu and strongly to extremely contaminated by Cd. Based on spatial distribution of concentrations and the Igeo, mining activity was the source of Cu and Cd in the Aqyazi River. Furthermore, the elevated Igeo of Cd at upmost northern station was not influenced by the mining activity, suggesting that there may be another upstream anthropogenic source of Cd. The CF values indicated the same trend as the Igeo. The PLI was calculated using all the metals analyzed in this study, and displayed that the sediments were not polluted. However, the PLI was re-calculated using only Cu and Cd and indicated that the sediments were polluted. Our results suggest further studies to trace another source of Cd upstream of the Aqyazi River and to investigate influence of the river waters on accumulation of heavy metals in soils and vegetables downstream.

Pollution status and ecological risk of heavy metals in the soils of five land-use types in a typical sewage irrigation area, eastern China.

Sewage irrigation has been widespread in the water shortage area of eastern China and inevitably tends to result in heavy metal accumulation in soils. A total of 148 surface soil samples from five land-use types were collected in Longkou, a typical sewage irrigation area of China, and As, Cd, Cu, Pb, and Zn concentrations were determined. The Nemerow index method and improved fuzzy comprehensive evaluation method were used to examine the pollution status of heavy metals. The potential ecological risk was evaluated by the Hakanson model by adjusting the assessment threshold, and its spatial distribution was interpolated using geostatistical techniques. As, Cd, Cu, Pb, and Zn accumulated in different amounts in the five land-use types. Urban industrial land and mining land were moderately polluted, irrigated land was slightly polluted, orchards were minimally polluted, and bare land was at a safe level of pollution. Cd exhibited high percentages of strong and severe levels of potential ecological risks. For Cd, irrigated land, orchard, and bare land mainly presented moderate risks, whereas urban industrial land and mining land mainly presented high risks. The comprehensive ecological risk of the five heavy metals was at a severe level for all tested land-use classes except for bare land.

Current status, spatial features, health risks, and potential driving factors of soil heavy metal pollution in China at province level

In this study we systematically reviewed 1203 research papers published between 2008 and 2018 in China and recorded related data on eight kinds of soil heavy metals (Cr, Pb, Cd, Hg, As, Cu, Zn, and Ni). Based on that, the pollution levels, ecological risk and health risk caused by soil heavy metals were evaluated and the pollution hot spots and potential driving factors of different heavy metals in different provinces were also identified. Results indicated accumulation of heavy metals in soils of most provinces in China compared with background values. Consistent with previous findings, the most prevalent polluted heavy metals were Cd and Hg. Polluted regions are mainly located in central, southern and southwestern China. Hunan, Guangxi, Yunnan, and Guangdong provinces were the most polluted provinces. For the potential health risk caused by heavy metals pollution, children are more likely confront with non-carcinogenic risk than adults and seniors. And children in Hunan and Guangxi province were experiencing relatively larger non-carcinogenic risk. In addition, children in part of provinces were undergoing potentially carcinogenic risks due to soil heavy metals exposure. Furthermore, in our study the 31 provinces in mainland China were divided into six subsets according to corresponding potential driving factors for heavy metal accumulation. Our study provide more comprehensive and updated information for contributing to better soil management, soil remediation, and soil contamination control in China.

Heavy metal uptake by wastewater irrigated potato plants grown on contaminated soil treated with hydrogel based amendments

Heavy metal uptake by food crops and the potential for groundwater contamination are of major concern in areas where untreated wastewater is used for irrigation. To minimize heavy metal uptake by wastewater irrigated food crops and to minimize its transport to deeper soil layers, the use of polyacrylamide super absorbent polymer (SAP) and SAP-gasified plantain peel biochar mix (SAP+GBC), as soil amendments, is proposed in this study. A sorption test was conducted to determine the ability of the treatments to adsorb heavy metals (Cd, Cr, Cu, Fe, Pb and Zn). Field experiment was conducted by growing synthetic wastewater irrigated potato plants ( Solanum tuberosum L.) in lysimeters packed with sandy soil, contaminated with heavy metals. Prior to conducting the study, heavy metals Cd, Cr, Cu, Fe, Pb and Zn were present in top 0.10 m of lysimeter soil within ranges of 15.6–23.9, 23.3–27.6, 30.3–62.2, 11538.6–10847.7, 64.9–131.3 and 38.7–46.8 mg kg −1 , respectively. Irrigation occurred eight times, at an interval of 10 days, based on the crop water requirement. After every irrigation, soil samples were collected from different depths (surface, 0.10, 0.30 and 0.60 m) for heavy metal analysis. Upon maturity, potato tubers, plant root, stems, leaf, tuber flesh and tuber peel tissues were sampled separately for heavy metal analysis. Soil samples, collected at the end of the experiment, were also subjected to pH and cation exchange capacity (CEC) analysis. Compared to the control, treatment SAP+GBC was able to retain significantly higher amounts of Cd, Cr and Fe in topsoil (0–0.10 m depth; p<0.05), whereas, the SAP treatment retained significantly higher amounts of Cd, Cu, Fe and Zn in topsoil (p<0.05). Both hydrogel based treatments (SAP and SAP+GBC) were able to significantly (p<0.10) reduce Cd uptake in tuber flesh (1.98 and 1.54 mg kg −1 , respectively) and peel tissue (20.75 and 23.89 mg kg −1 , respectively), as compared to the control (2.63 mg kg −1 in flesh and 43.87 mg kg −1 in peel). Concentrations of Zn in tuber flesh tissue for both, SAP (8.30 mg kg −1 ) and SAP+GBC (8.65 mg kg −1 ) treatments were found to be significantly (p<0.05) lower than that of the control (15.28 mg kg −1 ), indicating the effectiveness of the treatments in reducing Zn uptake by potato tubers. Treatment SAP+GBC was also able to significantly (p<0.05) reduce Pb uptake in tuber flesh (0.05 mg kg −1 ) and peel tissue (1.64 mg kg −1 ), as compared to control (0.09 mg kg −1 in flesh and 4.99 mg kg −1 in peel). Overall, it was found that tuber peels had significantly higher levels of heavy metals, as compared to tuber flesh. The present study indicates that the hydrogel based amendments have the potential to reduce the uptake of Cd, Pb and Zn metals, by wastewater irrigated potato tubers grown on sandy soils. • Irrigating potato with wastewater led to accumulation of heavy metals in soil. • Both treatments led to reduced Cd and Zn uptake by potato tubers. • Treatment SAP+GBC led to reduced Pb uptake in potato tubers. • SAP+GBC treated soil retained higher levels of Cd, Cr and Cr in topsoil. • SAP treated soil retained greater amounts of Cd, Cu, Fe and Zn in topsoil.

Phytoremediation: A Promising Approach for Revegetation of Heavy Metal-Polluted Land.

Heavy metal accumulation in soil has been rapidly increased due to various natural processes and anthropogenic (industrial) activities. As heavy metals are non-biodegradable, they persist in the environment, have potential to enter the food chain through crop plants, and eventually may accumulate in the human body through biomagnification. Owing to their toxic nature, heavy metal contamination has posed a serious threat to human health and the ecosystem. Therefore, remediation of land contamination is of paramount importance. Phytoremediation is an eco-friendly approach that could be a successful mitigation measure to revegetate heavy metal-polluted soil in a cost-effective way. To improve the efficiency of phytoremediation, a better understanding of the mechanisms underlying heavy metal accumulation and tolerance in plant is indispensable. In this review, we describe the mechanisms of how heavy metals are taken up, translocated, and detoxified in plants. We focus on the strategies applied to improve the efficiency of phytostabilization and phytoextraction, including the application of genetic engineering, microbe-assisted and chelate-assisted approaches.

Ecological security and health risk assessment of soil heavy metals on a village-level scale, based on different land use types.

Land use affects the accumulation of heavy metals in soil, which will endanger ecological safety and human health. Taking the village as an administrative unit, the ecological safety and health risks of heavy metals, namely, Cr, Cu, Zn, and Pb in soils in the Houzhai River Watershed of Guizhou Province, China, were evaluated based on land use types by the Hakanson potential ecological risk methods and human health risk model. Results showed that the spatial heterogeneity of Cu and Zn was greatly affected by primary structural factors, and Cr and Pb were interfered by both structural factors and human activities. The geo-accumulation index of the heavy metals showed a light pollution in the study area. The comprehensive potential ecological risk of heavy metal in the area was divided into three levels: slight, moderate, and intense, and it is spatially high in the northwest and low in the southeast. Both non-carcinogenic risk and carcinogenic risk of the heavy metals to the human body are not significant and are acceptable. The risks of children are higher than adults, and direct intake is the primary route of exposure in the area. The potential ecological risk and human health risk of soil heavy metals are relatively obviously affected by digital elevation data and normalized vegetation index. The study has certain reference value for the prevention and control of regional soil heavy metal risk.

Spatial-temporal Variation and Source Change of Heavy Metals in the Cropland Soil in the Industrial City

Environmental policy regulation affects the accumulation of heavy metals in soil. Two soil surveys were conducted in farmland in industrial cities. Classical statistical and geostatistical methods were applied to examine the content changes and spatial-temporal distribution characteristics of Cd, Pb, Cu, and Zn in soil. The pollution sources and their contribution rates were further analyzed by a principal component analysis/absolute principal component scores (PCA/APCS) model. The results indicated that the concentrations of Cd, Pb, Cu, and Zn increased during the two periods. The content of Cd and Pb in the spatial distribution decreased from northwest to southeast in both periods. The content of Cu and Zn decreased from north to south in 2011, and gradually decreased from northwest to southeast in 2017. Compared with 2011, the contribution rate of industrial activities increased by 5.58%, 10.4%, and 20.4% for Cd, Cu, and Zn, respectively, but decreased by 19.7% for Pb. The contribution rates of the other factors to Cd and Pb increased by 3.76% and 24.83%, respectively, and decreased by 9.27% and 4.31% for Cu and Zn, respectively. Relevant measures have reduced the accumulation of Pb in regional soil caused by industrial activities, but not Cd, Cu, or Zn. In addition, new Cd and Pb pollution sources need to be paid attention to.

Accumulation of heavy metals in soil and maize after 17-year pig manure application in Northeast China

Application of composted pig manure (PM) is a traditional practice to improve soil fertility, whereas generally leads to some environmental questions. The effects of PM application on Cd, Cu and Zn accumulation in soil and maize were investigated based on a long-term field trial in Northeast China, including control (CK), PM&lt;sub&gt;L&lt;/sub&gt;, PM&lt;sub&gt;M&lt;/sub&gt;, and PM&lt;sub&gt;H&lt;/sub&gt;, receiving 0, 100, 250 and 500 kg total N/ha/year from 2002 to 2008 and 0, 10, 25 and 50 t fresh weight/ha/year from 2009 to 2018, respectively. Results showed that long-term soil application of PM increased maize grain yield, soil organic carbon (SOC) contents, coupled with significant accumulation and availability of Cd, Cu, and Zn in soil (0–15 cm). Compared with CK, the soil total Cd, Cu and Zn concentrations significantly increased by 105, 287 and 108% at high PM rate, respectively. Notably, the increments enhanced these heavy metals storage in maize roots rather than in grains. Moreover, the application of PM confirmed vertical transport of heavy metals in the tested soil, particularly for Cd and Cu in PM&lt;sub&gt;H&lt;/sub&gt; treatment. Overall, the repeated application of PM can cause the accumulation and leaching of Cd, Cu and Zn in soil.

Assessment of the health risks of heavy metals in soils and vegetables from greenhouse production systems in Iran

Overuse of chemical and organic fertilizers in greenhouse (GH) crop production may cause the accumulation of heavy metals in soils and risks to human health. The aims of this study were to compare physical and chemical properties of GH with open-field (OF) soils, to clarify the buildup of heavy metals and phosphorus (P) in soils, and to assess the risks of selected heavy metals in soils and cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) from GH vegetables in Hamedan, western Iran. The average total and Olsen P of GH soils were significantly higher than the OF soils for both vegetables. The order of total and available heavy metal content in tomato GH soils has been set as zinc (Zn) > nickel (Ni) > chromium (Cr) > lead (Pb) > copper (Cu) > cadmium (Cd) and Zn > Cr > Cu > Pb > Ni > Cd, respectively. The same order was found for cucumber GH soils, except that the position of Pb and Cu was changed. The results indicated that in both GH cucumber and tomato soils, the mean content of total and available Zn, available Cu, Ni, and Pb, was extra than in OF soils. There were no significant differences between average total Cr, Cu, Ni, and Pb in GH and OF soils. Tomato vegetables had higher heavy metal content and transfer factors, particularly for Cr than cucumber vegetables. According to the health risk indices, Cr and Pb represented a high potential risk for health through cucumber and tomato consumption. There were limited Cd, Cu, Pb, and Zn inputs from the irrigation waters, while the input of Cr and Ni may be important. However, the amount of manure application and heavy metal content of the manures was significant.

Physiological, biochemical and transcriptomic responses of Medicago sativa to nickel exposure

Metal accumulation in soil could lead to severe damage to plants, animals, and humans. The present work aims to evaluate the effects of nickel (Ni) exposure on Medicago sativa at physiological, biochemical, and transcriptomic levels. Plants were exposed to five increasing concentrations of Ni (0, 50, 150, 250, and 500 mg/kg) for 60 days. Agronomic parameters (fresh and dry matter) and chlorophyll content (Chl) were determined in an alfalfa plant. Chemical analyses were conducted, involving the determination of Ni loads in plants (roots and shoots). Moreover, malondialdehyde accumulation (MDA), glutathione-S-transferase (GST), and peroxidase activities, termed as oxidative stress biomarkers, were measured. The gene expression levels of Prx1C, GST, and phytochelatins (PCs) were determined at different nickel concentrations. Our results showed that Ni concentration in plants increased significantly along with Ni concentration in the soil. Regarding oxidative stress biomarkers, Ni contamination caused an increase in peroxidase and GST activities, with a remarkable accumulation of MDA, especially for the highest Ni concentration (500 mg/kg of Ni). Our data showed also a significant upregulation of Prx1C and GST genes in shoots and roots. The PCs’ gene expression was significantly enhanced in response to the different nickel concentrations, suggesting their important role in Ni detoxification in alfalfa plants. Our data provided evidence about the clear toxicity of Ni, an often-underestimated trace element.

Levels of Heavy Metals in Banana, Cocoa and Oil Palm Farming Systems in Cameroon

The potential accumulation of heavy metals in soils due to rapid urban and industrial development, and increasing reliance on agrochemicals in the last several decades has been of public concern. Excessive heavy metal accumulation in soils may not only result in environmental contamination, but excessive heavy metal uptake by crops may affect food quality and safety. The heavy metal concentrations of soils in banana, cocoa and oil palm farming systems in Fako Division of the South West Region of Cameroon were studied. For soil quality assessment, soil samples were collected at two depths: 0-15 cm and 15-30 cm and analyzed for seven heavy metals (Cd, Cu, Cr, Ni, Mn, Pb and Zn) using inductively coupled plasma optical emission spectrometer (ICP-OES). Cd levels in these soils were below the limits of detection (LOD) at both depths. Average contents of Cd, Cu, Cr, Mn, Ni, Pb and Zn in mg/kg ranged in the order: Cd (&lt; LOD) &lt; Pb (10.7 -17.1) &lt; Cu (59.7-112.7) &lt; Ni (100.2 -174.5) &lt; Zn (129.7-180.4) &lt; Cr (192.7-685.3) &lt; Mn (2731.5-5053.5) for both depths. The soils were all acidic (pH; 4.2-5.5). There were significant variations (p≤0.05) in Cu, Cr, Mn and Zn concentrations within different farming system(s). The soils of the studied farming systems had heavy metal levels within the allowable limits for agriculture. However, the levels of Cu, Cr and Ni were higher in some samples. Although these soils are considered to be unpolluted, care should be taken to avoid high concentrations of heavy metals.

Taraxacum officinale Wigg as a bioindicator of heavy metals accumulation in soil of the mining and metallurgical region

Taraxacum officinale Wigg as a bioindicator of heavy metals accumulation in soil of the mining and metallurgical region

Risks of heavy metals accumulation in soil and crop irrigated with municipal wastewater in urban area of Mymensingh

Risks of heavy metals accumulation in soil and crop irrigated with municipal wastewater in urban area of Mymensingh