Lead-contaminated Soil Research Articles

Study of the Contamination of Soils Irrigated from Diwaniyah River with Lead / Iraq

This study was conducted to find out the effect of adding different pollutants (sewage water, liquid industrial water and heavy water) throwing into the river in Diwaniyah governorate on the concentration of Lead in river water and the effect of irrigation on the presence of this element in the soils during the different seasons of the year.Soil samples were taken for two dimensions, the first at a distance of 100-150 meters from the source of pollution and for three depths, the first depth 0-30 cm, the second depth 30-60 cm, the third depth 60-90 cm, and the second dimension samples were taken at a distance of 5-5.5 km from the same source and also for three depths and three iterations for all sites and during four seasons: summer (July) 2019, autumn (October) 2019, winter (January) 2020, spring (April) 2020 with three locations, the first site is located at the entrance of Diwaniyah city (Sania area), which represents the control treatment as it is located before the various pollution ports that flow into the river (such as sewage, hospital waste, factory waste, sewage … etc) and the second site in the city center (Rifaat quarter) and the third site in the (Sudair area), which represents the last site of the Diwaniyah city after the end of all estuaries and sources of pollution.The results of the study were reached that the soil contamination with Lead was highest in the surface layer compared to the other of the depths, and the first dimension (100-150) m from the source of pollution is the highest compared with the second dimension (5-5.5) km, this indicated to a decrease in Lead concentration while moving away from the source of pollution. The highest concentration of Lead in the summer was 3.11 micrograms. Kg−1 in the first depth of the third site at a distance of (100-150 m), while the lowest concentration in the winter was 0.22 micrograms.Kg−1.At the third depth of the first site at a distance (5-5.5) km, this indicates that Lead contamination of soils is highest in the surface layer and increases with the slope of the river, and the concentration of Lead was decreasing with depth in all four seasons of the year and for all studied sites.

Utilization of biochar and Trichoderma harzianum to promote growth of shallot and remediate lead-contaminated soil

This study aimed to determine the effect of biochar and Trichoderma harzianum toward lead removal in soil, lead absorption, lead content in plant tissue also growth and yield of shallot cultivated on lead-contaminated soil. The experimental design used was a completely factorial randomized block design consisting of 2 factors. The first factor was corn cobs biochar which was applied 1 week after basic fertilizer treatment and consisted of 4 levels, namely B0: without biochar, B1: 2.5 t ha-1, B2: 5 t ha-1, and B3: 10 t ha-1. The second factor was the dosage of liquid of Trichoderma harzianum, namely TR0: without T.harzianum, TR1: 10 mL L-1, and TR2: 20 mL L-1, which was applied three times at 14, 28 and 42 days after planting. Data were analyzed using the F test and continued with DMRT (Duncan Multiple Range Test) at P= 0.05 level. The results showed that the application of 5 t biochar ha-1 was able to remove lead and decreased lead uptake in plants. Application of T. harzianum could remove and decrease absorption in plant tissue biochar was not able to increase the growth of shallot while T. harzianum increased the number of leaves and the number of tubers.

Cyclocarya paliurus for Phytomanagement of Lead-Contaminated Soils.

Cyclocarya paliurus seedlings were cultivated in three types of lead (Pb)-contaminated soils with Pb concentration of 305 ± 17mg/kg (T1), 1964 ± 59mg/kg (T2) and 3502 ± 107mg/kg (T3), respectively. The results showed that after 180days of cultivation, the contents of exchangeable and carbonate-bound Pb fractions significantly decreased in T1 and T2, but increased in T3. The growth indices of C. paliurus seedlings decreased with increasing Pb concentration; however, no difference was found between that in T1 and in Pb-free soil. The Pb concentration in the roots was an order of magnitude higher than that in the stems and in the leaves. The bioconcentration factor (BCF) of the leaves was the lowest among the three tissues investigated, and decreased with the higher concentration of Pb in the soils. These results suggest that C. paliurus can be used as a sustainable and profitable plant for the phytomanagement of Pb-contaminated soil.

Five-weeks pot trial evaluation of phytoremediation potential of Helichrysum splendidum Less. for copper- and lead-contaminated soils

This paper describes an investigation into the accumulation and distribution of Cu and Pb in Helichrysum splendidum, to assess the potential use of the plant in the phytoremediation of Cu- and Pb-contaminated soils. Plants of the same age were exposed to soils artificially contaminated with 10, 50, 100, 500 and 1000 mg/L Cu(II) and Pb(II). Although plant growth was not affected by the presence of Cu, high concentrations of Pb (> 500 mg/L) stunted the plants. Chlorophyll production was slightly reduced when plants were exposed to high concentrations of Cu (> 500 mg/L), whereas all the plants growing in Pb-contaminated soils indicated low levels of chlorophyll. Significant amounts of Cu and Pb were accumulated in the roots, with corresponding bioconcentration factors of > 1. Translocation of Cu to the shoots was restricted for plants growing in > 500 mg/L Cu-treated soils, whereas Pb was translocated to the shoots for all treatments, with translocation factors > 1. The Cu and Pb tolerance mechanism was ascribed to chelation and free radical scavenging, through the production of phenolic compounds. Helichrysum splendidum is able to adapt to and ameliorate soils contaminated with low to high levels of Cu(II) and Pb(II) and has potential for application in phytoextraction and phytostabilization of contaminated soils.

The effect of long-term freeze-thaw cycles on the stabilization of lead in compound solidified/stabilized lead-contaminated soil

The solidification/stabilization (S/S) method is a common technique for the remediation of soils polluted by heavy metal. This study, thus, evaluated the long-term effectiveness, in term of the stabilization of lead in the solidified/stabilized soils, under freeze-thaw cycles, which are important physical processes that lead to material weathering. Three types of compound binders were obtained by mixing the three most commonly used binders (cement, quicklime, and fly ash) in varying proportions for the remediation of lead-contaminated soils. The leachability, chemical forms, and microstructure characteristics of the solidified/stabilized samples after various numbers freeze-thaw cycles (i.e., 0, 30, 90, and 180 times) were examined by utilizing the toxicity characteristic leaching procedure (TCLP) test, chemical speciation analysis, and scanning electron microscopy (SEM). The results showed that the long-term freeze-thaw cycles lead to decreased leachate pH and increased lead concentration in the leachate. The larger the total mix quantities of cement and quicklime, the lower the concentration of lead was presented in the leachate, however, indicating that cement and quicklime are more effective in immobilizing lead ions than fly ash. Chemical speciation analysis revealed that the long-term freeze-thaw cycles did, however, reduce the content of carbonate-bound form lead while the quantity of the ion-exchange forms. SEM further confirmed the observed leaching characteristics and chemical speciation characteristics. In addition, it indicated that, at the same number of freeze-thaw cycles, high initial lead concentrations substantially delayed the hydration process of cement in solidified lead-contaminated soil.

Challenges and Opportunities for Communicating Lead Exposure Risks in Idaho’s Silver Valley

Lead-contaminated soil and dust remain a primary hazard for mining-impacted regions around the world. Exposure to lead is linked to a range of negative health consequences like developmental delays in children. Residents and visitors in mining-impacted regions can practice health protective behaviors such as handwashing and avoidance of possibly contaminated areas to limit exposure. Health districts face the challenge of informing people about these recommended protective behaviors. The objective of this case is to describe the risk communication strategies employed by a health district and to evaluate residents’ perceptions of the risk of lead exposure in a mining-impacted region of northern Idaho. The case examination draws from risk communication literature, the experiences of the health district, and a community survey. The survey results suggest that appropriately tailoring health risk messages based on elevating recipients’ risk perceptions and efficacy levels may help to encourage protective behaviors. Because lead hazards pose dynamic risks in mining-impacted communities, it is also important to periodically update health risk messages through two-way information exchanges between experts and nonexperts. Lessons learned from this case can be applied to improve health through risk communication in other communities where lead hazards pose threats to human health.

Glutathione and calcium biomineralization of mulberry (Morus alba L.) involved in the heavy metal detoxification of lead-contaminated soil

This study intended to investigate the responses of glutathione (GSH) metabolism and calcium (Ca) secretion in mulberry (Morus alba L.) leaves under different levels of Pb contaminated soil and their correlations with leaf Pb ion accumulations. Using a greenhouse experiment, we measured the growth, Pb and calcium contents, glutathione metabolism, and leaf morphology traits of mulberry seedlings under four soil Pb levels. Mulberry exhibited a considerable adaptability to soil Pb, and no significant decrease in biomass was observed across the various soil Pb treatments. The glutathione metabolism of mulberry was related to the soil Pb, and the relative expression level of the glutathione synthetase gene was sensitive to the presence of Pb ions. The Pb ions absorbed by mulberry accumulated primarily in the roots, and only under heavy Pb concentrations (800 mg kg−1) would Pb ions be significantly transferred to leaves. The cystoliths excreted from leaves might not play a role in the detoxification of Pb; however, soil resident Pb affected cystolith development patterns and associated calcium regulation. Calcium oxalate crystals may directly participate in the Pb detoxification process in leaves, particularly under severe soil Pb stress. Under extreme soil Pb treatments, the mulberry leaves thickened, while epidermal cells and veins increased to facilitate the transport of Pb ions to the aerial organs. Mulberry can acclimatize to severely Pb-contaminated soil by enhancing glutathione metabolism, adjusting leaf morphologies, and enhancing calcium oxalate crystal excretion. The excretion of Pb-Ca oxalate complexes might serve as detoxification for Pb-contaminated soils.

Remediation of Lead-contaminated Farmland Soil: Efficacy of Low-cost Natural Amendments in [Im]mobilization of Lead

The control of Pb mobility is a success key in remediation of contaminated soil. This research aimed to explore the effective low-cost amendments in mobilizing or immobilizing lead in contaminated soil, assess environmental risk, and evaluate important amendment properties. Lead-contaminated soil was incubated with 13 materials included chars, bioslurry, limes, rice husk, gypsum, citric acid, natural organic acids and the efficiency of lead immobilization (E) was studied. Soil incubated with 10% amendments was sequentially extracted to determine Pb geochemical fractions and its risk. Selected amendment properties were evaluated through a correlation study with E. The results showed that 6 amendments immobilized lead in the order of chars > gypsum > bioslurry > rice husk. Chicken manure and chicken bone biochars, effectively decreasing lead solubility, were the best immobilising amendments, redistributed lead into the residual fraction and remediated the soil from moderate to low environmental risk. The order of mobilizing amendments was: citric acid > baby orange juice > limes > tamarind > lemon juice > tomato. The citric acid was the most effective mobilizing amendment which increased soluble lead and shifted the soil into high environmental risk status. The three most important amendment properties in influencing soil-Pb mobility were pH, P, and Ca content.

Derivation of empirical model to predict the accumulation of Pb in rice grain.

Lead contamination in soil has become a worldwide threat on food security and human health. To assess the Pb bioavailability and evaluate the safe use of low Pb polluted soil for food production, the speciation of Pb in 19 types of paddy soil were investigated by chemical extraction and X-ray absorption near-edge structure (XANES), and the uptake and accumulation characteristics of Pb in different soil-rice systems were investigated. Moreover, an empirical model was established to predict the content of Pb in rice grain, and field validation was conduct to evaluate model performance. Results showed that the proportion of available Pb in different soil satisfied normal distribution N (0.47, 0.23). Pb(CH3COO)2, GSH-Pb, PbO, PbHPO4 and Pb3(PO4)2 performed well in characterizing the speciation of Pb in different rhizosphere soils, and PbHPO4 accounted for more than 70%. The exceedance of Pb in grain in CK, 0.5X and 1X treatment were 10.5%, 36.1% and 42.1%, respectively, and the accumulation of Pb in grain was significantly related with Pb content in root. Carbonate and organic bound Pb in rhizosphere soil were two major Pb species that influenced the accumulation of Pb in rice. Moreover, content of total Pb, clay and SOM performed well in predicting the Pb content in grain, both for pot and field samples. Above all, our predicting model worked well in evaluating Pb accumulation in rice grain among low polluted paddy farmland (Total Pb<300mg/kg).

Assessment Of Lead Content In Soil Samples Obtained From Four Different Sites Of Kabwe, Central Province Of Zambia

Pollution has increased soil lead levels to several thousand parts per million; the primary cause of soil lead contamination in Kabwe district is the weathering from the former Zinc-lead mine. Soil lead is a health risk when directly ingested or inhaled as and it is of particular concern for children less than 6 years because of its implication on their growth. Hence this study set out to assess the lead soil content in four different sites of Kabwe district, Central province of Zambia. Literature was reviewed from studies that covered soil lead contamination. A quantitative analytical study was carried out, and it involved geographical mapping of four different sites the north, South, East, and West of Kabwe district which were conveniently selected to collect soil Samples which were taken to The University of Zambia School of Mines, Geology Engineering Laboratory to determine the Levels of soil Lead content using a technique called Geo-Chemical Analysis. The results suggest that the Chowa area is highly polluted with lead metal according to the globally recommended WHO guidelines and Zambia Environmental Management Agency, which all states that Residential areas should not exceed 400Kg/mg or parts per million.

Lead Contamination of Soils, Sediments, and Vegetation in a Shooting Range and Adjacent Terrestrial and Aquatic Ecosystems: A Holistic Approach for Evaluating Potential Risks

Lead Contamination of Soils, Sediments, and Vegetation in a Shooting Range and Adjacent Terrestrial and Aquatic Ecosystems: A Holistic Approach for Evaluating Potential Risks

Method for analysis of environmental lead contamination in soils.

A method for lead (Pb) detection in soil is presented. Pb is a dangerous environmental pollutant that is present in soils, posing a health risk to millions of people worldwide, and regular monitoring of Pb contamination in soils is essential to public health. Many sensitive methods for detection of heavy metals in solid matrices exist, but they cannot be performed on-site because they are costly (>$30 per sample), require trained personnel, and many classical sample preparation methods are not safe to bring into the field. We describe an alternative process, combining a safer sample preparation method with electrochemical analysis. The process requires minimal training, making it an attractive overall method for regular environmental screening of Pb in soils. Extract obtained from the soil is pH adjusted and analyzed using a stencil-printed carbon electrode and square wave anodic stripping voltammetry. In this work, a study of 15 neighborhood soils examining the concentration of Pb present post-extraction was performed to demonstrate the method. The limit of detection for the electrochemical analysis was calculated to be 16 ppb-well below the United States Environmental Protection Agency's action limit for Pb in soils (400 mg kg-1 or 4000 ppb)-and third party inductively coupled plasma-optical emission spectroscopy analysis validated the results obtained in this study to within ±17% on average.

Cd and Pb in the “soil-plant” system of Holosiyiv green park area in Kyiv

In this paper, the content of metals (Cd and Pb) was investigated in soil-plant system of Holosiyiv green park area in Kyiv. Kyiv is the capital and largest city of Ukraine, and has an anthropogenic load. Metals pollution in various degrees in green park areas may affect people’s health through different paths. We propose to control the lead contamination in soil because Pb concentration levels were above when compared with background values in almost all samples of soil and exceeded the maximum permissible concentration in sites of top of hills in park. Moreover, the obtained results indicated high concentrations of lead in studied plants; most of them are medicinal and traditionally used by people. The highest phytomass concentration of Pb was observed in Asarum europaeum L., whereas Impatiens parviflora DC and Urtica dioica L. had the highest plant up-taking indexes for both studied metals.

LEAD IMMOBILIZATION IN ARTIFICIAL CONTAMINATED SOIL USING SULFUR-IMPREGNATED CARBONACEOUS BAMBOO

A novel carbonaceous immobilizing agent for heavy metal contaminated soil was prepared from bamboo using sulfur immersion and pyrolysis, and the lead immobilization in artificial contaminated soils using sulfur-impregnated carbonaceous material was estimated. The bamboo was powdered, dried, and then immersed in 0.1 - 1 M K2S solution for 0 - 24 h to prepare sulfur-immersed materials. The immersed-materials were heated at 400 oC for 1 h in nitrogen gas to produce the sulfur-impregnated carbonaceous material by pyrolysis. The abilities of the product to immobilize lead from aqueous solution were examined to obtain the products with high lead immobilization ability. With increasing K2S concentration, the immobilization ability of the product for lead gradually increases and then above 0.75 M K2S those are almost constant, while 15 min is sufficient for the immersed time to obtain the product with high lead immobilization ability. The product prepared from material immersed in more than 0.75 M K2S solution for more than 15 min has a maximum immobilization ability for lead ion of 2.78 mg/g. The lead immobilization using the sulfur-impregnated product is sustainable due to the formation of leadhillite [Pb4SO4(CO3)2(OH)2] and shannonite [PbCO3‧PbO]. The product can immobilize lead ion in various artificial lead-contaminated soils. By mixing artificial leadcontaminated soil with the sulfur-impregnated product, the eluted solution became neutral, and the eluted concentrations of lead ion dropped below the Japanese elution standard for soil.

Removal of lead ions in an aqueous solution by living and modified Aspergillus niger.

An indigenous lead-tolerant fungal strain was isolated from lead-contaminated soil and identified as Aspergillus niger, via 18S rRNA gene sequencing. We determined the adsorption and accumulation of Pb(II) by living A.niger and the adsorption of Pb(II) via modified A.niger. This strain resisted and removed 96.21%-100% Pb(II) ranging from 2 to 8mmol/L Pb(II). Pb-containing particles were observed outside of the cell, and lead was detected inside the cell under scanning electron microscopy and transmission electron microscopy. The process of measuring the adsorption ability of modified fungal biomass, freeze-dried, high-temperature, and alkali-treated fungal samples was analyzed; they adsorbed 25.02%, 8.76%, and 15.05% Pb(II) under 8mmol/L Pb(II) in 43, 10, and 10hr, respectively. These three types of modified A.niger fit the pseudo-second-order model equation well. PRACTITIONER POINTS: Isolation and identification of effective Pb(II) removal strain from the soil around Dexing lead-zinc mine. The ability of living and modified Aspergillus niger to remove Pb(II) in an aqueous environment was evaluated. Lead distributions inside and outside the cell were analyzed by SEM and TEM. Kinetic models for modified biomass adsorbing Pb(II) were made for describing adsorption process.

Microbe-EDTA mediated approach in the phytoremediation of lead-contaminated soils using maize (Zea mays L.) plants

In the current study, we investigated the potential of Cronobacter sakazakii- ethylenediaminetetraacetic acid (EDTA) assisted phytoremediation potential of Zea mays L. to remediate lead (Pb)-contaminated soils. The C. sakazakii exhibited various stress tolerance mechanisms via plant growth promoting (PGP) traits, intrinsic extracellular enzyme production and antibiotic resistance. A greenhouse experiment was conducted to examine the dual effects of plant growth promoting endophytic bacteria (PGPEB)-chelator synergy in maize plants under different Pb contaminated soil regimes. C. sakazaii-EDTA (5 mM EDTA kg−1) complex significantly (p < 0.05) enhanced plant growth and biomass (48.91%); chlorophyll a, b and carotenoid contents (27.26%, 25.02% and 42.09%); relative water content (61.33%); proline content (63.60%); root and shoot Pb accumulation capacity (52.31% and 44.71%) in Pb contaminated soils. This may suggest the efficacy of current approach in enhancing plant tolerance capability toward Pb-uptake and phytoremediation capacity. Moreover, maize plants showed differential response to Pb availability in soil-1 (S1; Pb spiked soil, 500 mg kg−1) and soil-2 (S2; aged-contaminated soil) under various treatments. We describe the intriguing role of C. sakazakii-EDTA-maize system for Pb decontamination which can be used as a base line to explore the proposed combinatorial approach for long-term trails under field conditions for reclamation of Pb-contaminated soils. Highlights The PGPEB-EDTA mediated potential of Z. mays against Pb spiked and industrial contaminated soils is noticed. Increased tolerance of Z. mays against Pb in association with C. sakazakii, and EDTA is reported first time. Enhanced accumulation of metals by Z. mays is reported under combined treatment of C. sakazakii, and EDTA. Inoculation of plants with C. sakazakii, and EDTA has positive effects on growth and accumulation of Pb by Z. mays.

Electro-Osmosis Treatment of Lead-Contaminated Soil with Carbon Fiber-Based Geotextile Electrodes

Electro-Osmosis Treatment of Lead-Contaminated Soil with Carbon Fiber-Based Geotextile Electrodes

Temporal and spatial changes of Pb in soils in Cuihu wetland, Beijing, China

ABSTRACT Protecting soil from Pb contamination has been a programme for a long time in China. However, research on lead pollution in wetlands remains rare. To understand the characteristics of Pb pollution in Beijing and the sources of contamination of different soil samples in wetlands, we collected samples during all four seasons from two soil horizons and analyzed their Pb concentrations and Pb isotope ratios. The average concentrations of Pb varied from 65.44 mg/kg in spring to 106.11 mg/kg in winter. Concentrations in autumn were significantly lower than those in spring and summer and were notably different between A and B Horizons (59.42 and 71.47 mg/kg, respectively). The Pb isotopic compositions show that Pb pollution results from a mixing of geogenic and anthropogenic materials. The ratios of 206Pb/207Pb and 206Pb/208Pb evidenced that coal combustion and vehicle exhaust are the main sources of lead contamination in the two horizons. These results will help in reducing lead contamination in soil by knowing the temporal and spatial variations and sources of lead in Beijing.

Biochar and alternate partial root-zone irrigation greatly enhance the effectiveness of mulberry in remediating lead-contaminated soils

Abstract Aims Soil lead contamination has become increasingly serious and phytoremediation can provide an effective way to reclaim the contaminated soils. This study aims to examine the growth, lead resistance and lead accumulation of mulberry (Morus alba L.) seedlings at four levels of soil lead contamination with or without biochar addition under normal or alternative partial root-zone irrigation (APRI). Methods We conducted a three-factor greenhouse experiment with biochar (with vs. without biochar addition), irrigation method (APRI vs. normal irrigation) and four levels of soil lead (0, 50, 200 and 800 mg·kg−1). The performance of the seedlings under different treatments was evaluated by measuring growth traits, osmotic substances, antioxidant enzymes and lead accumulation and translocation. Important Findings The results reveal that mulberry had a strong ability to acclimate to soil lead contamination, and that biochar and APRI synergistically increased the biomass and surface area of absorption root across all levels of soil lead. The seedlings were able to resist the severe soil lead contamination (800 mg·kg−1 Pb) by adjusting glutathione metabolism, and enhancing the osmotic and oxidative regulating capacity via increasing proline content and the peroxidase activity. Lead ions in the seedlings were primarily concentrated in roots and exhibited a dose–effect associated with the lead concentration in the soil. Pb, biochar and ARPI interactively affected Pb concentrations in leaves and roots, translocation factor and bioconcentration. Our results suggest that planting mulberry trees in combination with biochar addition and APRI can be used to effectively remediate lead-contaminated soils.

Enhanced Removal of Lead from Soil Using Biosurfactant Derived from Edible Oils

ABSTRACT Lead contamination in soil due to anthropogenic activities has amplified and therefore, remediation is of prime significance due to its nonbiodegradability and toxicity effects. This study focuses on lead removal from the soil collected from a rifle range using biosurfactants produced from native microorganisms and edible oils. Native microorganisms in contaminated soil served as a source for biosurfactant production aided by edible vegetable oils such as palm oil and gingelly oil. Preliminary isolation and characterization studies indicated the presence of Pseudomonas aeruginosa that produced biosurfactant and removed lead simultaneously. Batch adsorption experiments showed 96%–99.6% of lead adsorption following Langmuir isotherm model. Lead desorption of 23.6% occurred without biosurfactant. Whereas in the presence of biosurfactants, enhanced desorption of 62.3% was observed. Of both palm oil and gingelly oil derived biosurfactants, the former reached a lead removal efficiency of 93.6% indicating the feasibility and effectiveness of the biosurfactants for contaminated site remediation.