Accumulation Of Heavy Metals In Soil Research Articles

Rice cultivation in former rubber land without soil remediation contribute toxicity risk of heritable heavy metals contamination

The rubber-based intercropping management system (RBIS) land management using chemical fertilizer and herbicides cause heavy metal accumulation in soil. Rice is a good heavy metal bioindicator to monitor soil quality and often integrated with RBIS while rubber trees are young as subsistence farming. Heavy metal accumulation in soil and hill paddy grown on former rubber land and specialized paddy field (control) had been assessed to determine whether harvested rice grain poses toxicity risk. Grain harvested from specialized paddy land was safer to consume as none of the selected heavy metal concentrations in rice grain had exceeded the permissible limit of Malaysia Food Regulation 1985 (MFR 1985). Meanwhile, hill paddy grown intercropping with young rubber trees on former rubber land had accumulated a high amount of heavy metals in rice grain whereby nonessential heavy metals like arsenic, cadmium and lead had exceeded the permissible limit of MFR 1985. Commonly, indigenous hill paddy belongs to tall paddy variety group can grow more than 120 cm tall. All harvested hill paddy landraces grown on specialized paddy field surpassed 120 cm. Nevertheless, all hill paddy landraces that were cultivated in former rubber land were below 100 cm tall indicated that heavy metal phytotoxicity occurred in plants. Rice grain produced in former rubber land poses toxicity risk to consumers due to unsustainable conventional agricultural management practice. Soil degradation needs to be prevented as it can impact food safety and food security. Further soil remediation requirement must be determined to ensure high productivity and safety.

THE EFFECTS OF THE APPLICATIONS OF ZEOLITE AND BIOCHAR TO THE SOILS IRRIGATED WITH TREATED WASTEWATER ON THE HEAVY METAL CONCENTRATIONS OF THE SOILS AND LEACHING WATERS FROM THE SOILS

The reuse of wastewaters for agricultural irrigation is a method used in arid and semi-arid regions. The heavy metal accumulation in soils caused by wastewaters and the heavy metals transported by the waters leaching into the underground from these soils are important environmental issues. The study investigates the effects of Biochar (Bc) and Zeolite (Zt) applications on the heavy metal accumulation in soils (entisol and vertisol) that were irrigated with treated urban wastewater (TWW). The effects of Bc and Zt on the heavy metal concentrations of the leaching water (LW) from the soils were investigated as well. In the study, increasing doses of Bc (1%, 2%, and 4%) and Zt (5%, 10%, and 20%) were mixed into two soil classes of heavy- and fine-textured soils. The mixtures were irrigated with TWW at certain intervals. At the end of the trial, the chromium (Cr), iron (Fe), nickel (Ni), cobalt (Co), copper (Cu), lead (Pb), and cadmium (Cd) contents of the samples collected from the soils and leaching irrigation waters were determined. The results revealed that Bc and Zt caused heavy metal accumulation in both soil classes, while they decreased the heavy metal concentrations of the LW. The adsorbents are commonly used as soil amendments and have been determined to cause heavy metal accumulation in soils but reduced the heavy metal concentrations in waters by serving as filters.

The assessment of soil contamination with heavy metals in the Vladimir city

To analyze heavy metal contamination of urbanized soil in the Vladimir city, the soil was sampled and studied. The city area is represented by sod-medium podzolic and gray forest urbanized soil. Soil samples analysis included lead, zinc, copper, nickel, manganese, cobalt and chromium. The resulted parameters were compared to the maximum permissible concentrations and background values. The regularities between the studied sites proximity to the industrial enterprises and heavy metals concentration in soil have been found. The coefficients of heavy metals accumulation in soil have been calculated and the metals as priority pollutants with the highest accumulation coefficient have been identified. By calculating the cumulative accumulation index, the city area has been differentiated according to the hazardous degree. The research peculiarity comprises the sampling locations selection – school sites, as the child population is the most vulnerable to the diseases, associated with the heavy metals accumulation in soil.

Quantifying the Contribution of Coking Industry to Soil Heavy Metal Accumulation in Beijing–Tianjin–Hebei Region, China and the Associated Risks

Quantifying the Contribution of Coking Industry to Soil Heavy Metal Accumulation in Beijing–Tianjin–Hebei Region, China and the Associated Risks

Irrigation water of different sources affects fruit quality attributes and heavy metals contents of un-grafted and commercial mango cultivars

In peri-urban areas, waste water is used to irrigate orchards due to scarcity of fresh water which increases heavy metals contents in soils, leaves and fruits. Due to excessive waste water irrigations, heavy metals enter into the food chain, which eventually causes metabolic disorders in humans. The present study was envisaged to investigate the effects of canal, tubewell and sewage water on the quality of mango fruits and heavy metals accumulation in soils, leaves and fruits. Leaf and fruit samples from an un-grafted (Desi mango) and six commercial cultivars of mango (Anwar Rataul, Aman Dusehri, Sufaid Chaunsa, Samar Bahisht Chaunsa, Kala Chaunsa and Anwar Rataul Late) grafted on Desi mango were collected from different mango orchards located in peri-urban areas of Multan (Pakistan) and analyzed for some physico-chemical attributes and heavy metals contents. Soil samples were also taken from these orchards irrigated with different water sources to assess the soils' heavy metals status. A significant variation was observed among the mango cultivars for their physico-chemical attributes. Sewage water irrigation improved total soluble solids (TSS), titratable acidity, ascorbic acid content, total phenolics, total carotenoids, total flavonoids and antioxidant activity of mango fruits. However, it did not affect fruit weight and shelf life. Among the heavy metals, copper and nickel contents were found in greater amounts in soils, leaves and fruits of sewage water irrigated orchards than canal and tubewell water irrigated ones. However, zinc and cadmium were not detected in any soil, water, leaf or fruit sample. The interaction among the sources of irrigation and the mango cultivars was significant for copper accumulation in different soil layers, copper and nickel accumulation in leaves of different mango cultivars, and fruit weight, titratable acidity, ascorbic acid content, total flavonoids and shelf life of mango fruits.

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.

Efficacy of drip irrigation in controlling heavy-metal accumulation in soil and crop

This study was aimed at identifying how drip irrigation could be useful in controlling heavy-metal issues, practically and affordably. A vegetable crop (i.e. cauliflower) was the subject of the test. Heavy-metal accumulation in soils and uptake by cauliflower curds were observed for two consecutive years. Municipal wastewater and groundwater were used for irrigation, to make it a comparative study. There were eight treatments: drip irrigation with groundwater through inline (non-pressure-compensating) surface drip (T1), inline subsurface drip (T2), bioline (pressure-compensating) subsurface drip (T3), bioline surface drip (T4) and the same drip systems using primarily treated municipal wastewater (T5to T8). The results showed that significantly higher concentrations of heavy metals – namely, copper, iron, manganese and zinc – were recorded in cauliflower curds irrigated with wastewater compared with those irrigated with groundwater. Subsurface placement of pressure-compensating drip laterals was found more effective in reducing the heavy-metal concentrations in both cauliflower and soil profile compared with surface-placed non-pressure-compensating drip laterals. This study suggests that drip irrigation systems could be an effective method to reduce heavy-metal concentration in vegetable crops and soils irrigated with treated municipal wastewater.

Impact of Intensive Farming on Soil Heavy Metal Accumulation and Biomarkers Responses of Earthworms Eisenia andrei.

In this work, we propose to evaluate the effect of agriculture intensification under greenhouses on the biochemical and transcriptomic responses of the earthworms Eisenia andrei. This work was conducted on two sites in Téboulba and Sahline (Monastir governorate) and a control site in an experimental plot that is undergoing organic farming. For this purpose, the earthworms Eisenia andrei were exposed to the soils during 7 and 14 days. The physicochemical properties of the soils were analyzed. The biochemical biomarkers of metallothioneins (MTs) and malondialdehyde (MDA) accumulations were also assessed. Moreover, the gene expression level of the MTs was analyzed. The results of our study revealed a significant trace element accumulation accompanied by a high level of MDA and MT proteins. Moreover, a significant expression of the MT gene was observed in earthworms exposed to the soils from Sahline and Téboulba. Hence, this work reveals that intensive agriculture can affect the biological responses of earthworms and consequently, the soil's biofertility.

Effect of cultivation time on soil heavy metal accumulation and bioavailability in Phyllostachys praecox stands

Phyllostachys praecox is a bamboo species cultivated for edible shoots under intensive management. However, the potential pollution risk of heavy metals in bamboo soils is not clear under the intensive management for a long term. The objective of this study was to evaluate the effect of cultivation time on soil heavy metal accumulation and bioavailability in bamboo stands subjected to intensive management. Soil samples were collected from a chronosequence of bamboo stands which had been cultivated for 0, 1, 2, 4, 8, and 10 years in Lin'an, Zhejiang Province of China. Eight heavy metals (Cu, Zn, Pb, Ni, Cr, Cd, As, and Hg) present in the soil were selected, and their potential pollution risk was evaluated by chemical speciation analysis. Possible heavy metal sources were explored using multivariate and cluster analysis. Our results showed that Zn, Cu, Hg, and Cd contents in the soil increased with the cultivation time, while Ni, Cr, Pb, and As levels were similar among all stands. Furthermore, the bioavailabilities of all analyzed heavy metals increased with the cultivation time. Multivariate and cluster analysis showed that sources of Ni, Cr, Pb, and As were likely lithogenic in origin, whereas input of Zn, Cu, Hg, and Cd was mainly due to cultivation practices. Current bamboo management strategies raised the potential risks of heavy metal pollution in bamboo shoots in the long term. Soil acidification in P. praecox stands induced by intensive cultivation should be controlled since it stimulated and improved the bioavailability of heavy metals. Appropriate management strategies should thus be adopted to ensure safe and sustainable production of bamboo shoots.

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.

Distribution of heavy metals in crop soils from an agricultural region of the Yucatan Peninsula and biochemical changes in earthworm Eisenia foetida exposed experimentally.

Heavy metals (HM) are natural components of agricultural soils. However, excessive use of agrochemicals (fertilizers and pesticides) can increase the concentration of these elements, making them harmful to crops and soil biota. Therefore, this study aimed to evaluate the concentrations of 6 HM (Cr, Mn, Cu, Zn, Al, and Fe) in soils collected from a typical agricultural region of the Yucatan Peninsula, Mexico, and relate their effects on weight, biotransformation (EROD, GST), and oxidative stress (SOD, CAT, LPO, and MT) in the earthworm Eisenia foetida. The results showed different concentrations of HM accumulation in soils, in the following order, Fe (598.74 ± 223.81μgg-1), Al (145.30 ± 33.54μgg-1), Cr (88.38 ± 36.23μgg-1), Mn (69.53 ± 22.48μgg-1), Zn (54.10 ± 12.04μgg-1), and Cu (24.91 ± 12.40μgg-1), the soils with maize, soybean, and chihua squash crops being the ones with the highest distribution and availability of these elements. These concentrations of metals did not produce mortality. However, Cr, Fe, and Al induced a significant biomass loss of E. foetida. The integrated biomarker response version 2 revealed that soil with maize cultivation was affected the most, with the earthworms exposed to this soil showing greater variations in the dominant biological responses including EROD, TBARS, SOD, and MT (IBRv2 = 9.73). PCA analysis indicated a strong positive relationship between these oxidative stress biomarkers and Cu and Zn concentrations. These findings provide a reference guide that should be part of the monitoring and management programs for different agricultural types in the region under study.

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.

Identification of the potential risk areas for soil heavy metal pollution based on the source-sink theory

From the perspective of the mechanism of soil pollution, it is difficult to explain the process of predicting the spatial distributions of soil heavy metal pollution using traditional geostatistical methods at a regional scale. Furthermore, few methods are available to proactively identify potential risk areas for preventing soil contamination. In this study, we selected 13 environmental factors related to the accumulation of soil heavy metals based on the source-sink theory. Then, the fuzzy k-means method in combination with the random forest (RF) method was used to classify potential risk areas. The concentrations and spatial distributions of the heavy metals were well predicted by RF, and the average values of the root mean square error of the prediction and R2 were 4.84 mg kg−1 and 0.57, respectively. The results indicated that the soil pH, fine particulate matter, and proximity to polluting enterprises significantly influenced the heavy metal pollution in soils, and the environmental variables varied significantly across the identified subregions. This study provides a theoretical basis for the sustainable management and control of soil pollution at the regional scale.

Modeling the spatial variations in anthropogenic factors of soil heavy metal accumulation by geographically weighted logistic regression

Quantifying the impacts of associated factors on soil heavy metal (HM) accumulation and mapping the accumulation risks can provide valuable information for the soil remediation and protection. This study investigates the risk of soil HM accumulation and its relationships with human activities, which were expressed by weighted industry distance (WID), weighted road density (WRD), and population density (LnPD). Three models, namely logistic regression (LR), geographically weighted logistic regression (GWLR), and kriging with external drift (KED), were used and compared. The results, which were based on the soil Pb contents in Wuhan city as an example, showed that the coefficients of LnPD, WRD and WID in LR model were all positive, meaning the increase of LnPD, WRD and WID will generally elevate the risk of Pb accumulation. Whereas in GWLR model, the coefficients were spatially varying, thus distinct dominant factors can be identified at every location by comparing the GWLR coefficients. Furthermore, GWLR gave significant higher model accuracy than LR, and had approximate but more straightforward explanatory power compared to KED. The results suggest that GWLR is a promising method in analyzing and mapping the spatial nonstationary relationships between the risk of soil HM accumulation and human activities.

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 (< LOD) < Pb (10.7 -17.1) < Cu (59.7-112.7) < Ni (100.2 -174.5) < Zn (129.7-180.4) < Cr (192.7-685.3) < 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

Particle-size distribution and heavy metals accumulation in soils of Rostov-on-Don

The surface horizons of the soils of traffic areas of Rostov-on-Don are characterized almost twice higher content of soil particles from 1 mm to 0,01 mm than native chernozems. The higher anthropogenic load provides the higher the content of sand fractions in the particle-size distribution. The accumulation of heavy metals (HM) in urban soils of roadside areas is relatively small, which is also due to a decrease of the soil sorption capacity. Significant excess of the estimated permissible concentrations was detected only for zinc and lead, and the higher the pollution level, the weaker the correlation between the particle size distribution and the HM content. This is justified by the influence of external factors on the accumulation rate of chemical elements.

Beyond mere pollution source identification: Determination of land covers emitting soil heavy metals by combining PCA/APCS, GeoDetector and GIS analysis

In this work, we propose a method that is not limited in the identification of the type of pollution source but it also suggests the land covers that emit heavy metals into the surrounding soils by introducing a three-stage procedure, as follows: (a) the Principal Component Analysis/Absolute Principal Component Scores technique is applied to the spatial distribution of soil heavy metal accumulations to identify the type of source that is responsible for soil heavy metal accumulation, (b) based on the spatial distribution of the principal component scores and on four selected driving factors (land cover, distance to mine or smelter, distance to road, and topographic elevation), the Geographical Detector model was used to identify the effect intensity of the driving factors on soil heavy metal accumulation and obtain the landscape type of pollutant sources, and (c) GIS analysis (buffer and overlap analysis) was performed on the principal component scores around the suspected land covers linked to the landscape type of pollutant sources to determine the land covers that, in fact, emit heavy metals into the surrounding soils. Based on the proposed approach, four mining and metallurgy land or land groups were determined to be the actual sources of soil heavy metal pollution in Daye city, Hubei Province, China. Lastly, a Multiple Linear Regression model with decay function was proposed to quantify the contributions of previously identified pollution sources to soil heavy metals accumulation. It was found that the HuangJin mountain quarry, the Tonglu mountain cooper mine (together with some related mineral processing and smelting enterprises), the Lion mountain mining and mineral processing base, and the large Oujia mountain mine are the four sources that contributed 3.2%, 34.3%, 8.3%, and 44% of the total soil heavy metal accumulations in the study area.

Hygienic assessment of living conditions and morbidity of the population in the port cities of the Sakhalin region

The aim of this study was to perform a comprehensive hygienic assessment of environmental conditions in the port cities of the Sakhalin region to identify priority risk factors affecting on population health and management decisions for the optimization of living conditions. As a result of the assessment of risk and damages for public health from the effects of air pollution on the dose-response, effects were found to excess of impact on the target organs by 10 times. The main ecotoxicant was determined to be manganese oxide, which is associated with a priority manganese content in soil samples ofport cities. The positive dynamics of the gain in the accumulation of soil heavy metals according to the total index indicates to the existence of problems for soil contamination. Analysis of demographic variables shows that the population of the Sakhalin region in general and the port cities in particular relates to a regressive type. The main causes of the population decline are mortality and migration outflow of able-bodied population in other regions of Russia. However, in the port cities there is an increase in the number of work places, contributing to an increase in the labor force. The primary and general morbidity of the population ofport cities is characterized by higher levels compared with the average for the Sakhalin Region and the Far Eastern Federal District. Among all the classes of diseases as priority ones there are marked “neoplasm”, “diseases of the nervous system”, “respiratory diseases”, “diseases of the skin and subcutaneous tissue”. Port cities occupy the top ranking places on the incidence of malignant tumors among the cities of the Sakhalin region.