Lead Concentrations In Soil Research Articles

Humik Asit Uygulamalarının Toprak Özellikleri ile Makro Besin Elementi, Mikro Besin Elementi ve Ağır Metal İçerikleri Üzerine Etkisi

This study was conducted on the YYU campus area as a field survey, according to the randomized block experimental design carried out in three replicated. The yellow and orange marigold species with humic acids (HA0;0 kg HA da-1, HA1;10 kg HA da-1, HA2;20 kg HA da-1, HA3;40 kg HA da-1) were used. At the end of the experiment, the soil samples taken from the field of study were analyzed organic matter, soil reactions, total salt content, lime content, nitrogen, phosphorus, potassium, calcium, magnesium, natrium, iron, manganese, zinc, copper, cadmium, nickel and lead contents. The increased humic acid applications have influenced pH (P<0.01), lime (P<0.01), organic matter (P<0.05) with phosphorus (P<0.01), iron (P<0.05), zinc (P<0.05) and nickel (P<0.01) contents. The effect variety (V) has been determined on the available of soil iron (P<0.01), zinc (P<0.01), cadmium (P<0.01), nickel (P<0.01), and lead (P<0.01) contents. The interaction of only affected the nickel (P<0.01) and zinc (P<0.01) contents. As a result, humic acid applications have an important and positive effect on many properties of soil.

Tolerance of lead by forage peanut cultivated in two soil classes

This work evaluated the potential of lead (Pb) phytoextraction by forage peanut, Arachis pintoi, cultivated on an Oxisol and a Gleysol. The samples of these soils received Pb as lead acetate heptahydrate (Pb(C2H3O2)2.7H2O) at rates of 0, 150 and 300 mg kg-1. The plants were cultivated in pots filled with Pb contaminated soil, and 105 days after planting were collected to determine shoot and root dry matter. Lead contents in soil and plant samples were determined using an atomic absorption spectrophotometer. Lead did not affect shoot dry matter yield in both soil classes, but linearly reduced root dry matter. The highest Pb concentration in the plant was detected in the A. pintoi shoot. This species is not a Pb accumulator but may be considered Pb tolerant and is indicated for revegetation programs in Pb-polluted soils.

Use of ordinary cokriging with magnetic susceptibility for mapping lead concentrations in soils of an urban contaminated site

Lead contamination is a prevalent issue affecting cities worldwide. Traditional fieldwork and laboratory analysis techniques can be time-consuming and costly. The purpose of this study was to evaluate the performance of ordinary cokriging (CK) when volume magnetic susceptibility (κ) is used as a co-variable for spatial interpolation of Pb in contaminated urban soils. The study was conducted in contaminated urban soils of a former unregulated landfill site. A total of 76 surface samples (0–10 cm) were collected using a systematic sampling grid separated by 20-m intervals. Magnetic susceptibility measurements were taken at a higher density of 10-m intervals with 288 measurements. Thus, it was used as an auxiliary variable to predict Pb concentrations by the CK procedure with an aim to improve spatial interpolation of Pb. To determine the effectiveness of CK over the ordinary kriging (OK) procedure, the spatial density of samples was reduced prior to interpolation. A total of ~ 15%, 25%, 35%, and 50% of the Pb samples were randomly selected and reserved for validation. Omnidirectional semivariograms and covariograms were fitted using log-transformed data prior to interpolation. Measurements of κ shared a significant relationship with Pb concentrations by the Spearman’s Rho correlation analysis (rs = 0.676, p < 0.01). The effectiveness of the CK procedure over OK was determined using validation datasets. Statistically, the results showed that lnPb when its auxiliary relations with lnκ were used in CK had overall lower “root mean square error” (RMSE) and predicted lnPb values from the CK procedure had a higher r2 value with measured lnPb than OK. A model produced by the CK procedure with a reduced spatial density of 49 Pb points provided the more accurate map with a RMSE of 0.550 and an r2 value of 0.730, p < 0.01 level. This technique can potentially reduce fieldwork and soil analysis costs considerably. Measurements of Pb and κ must share a substantial level of spatial continuity to implement CK effectively. Where applicable, it can be used in the site-specific evaluation of hazard posed by Pb exposure to ecosystems, human health or water bodies in urban green spaces, roadside soils, allotments or brownfield sites.

Content and Distribution of Biogenic and Toxic Elements in Soils and Vegetation of the Chulyshman River in the System of High-altitude Zone (Mountain Altai)

The content and distribution of nutrients (manganese, copper) and toxic elements (lead) in the soils and vegetation of the potentially recreational area of the Gorny Altai – the r. Chulyshman. It was established that the level of total lead content in soils is characterized as “low”, copper – “medium”. The content of mobile forms of copper and lead refer to the “average” gradation, which indicates the absence of contamination of the studied soils. Concentrations of the studied elements in the soils do not exceed the values of the APC and MPC adopted in Russia and abroad. Despite the obvious differences in the distribution of chemical elements in the soil profile, general patterns are also observed, due to the composition and properties of the soil. The biogenic accumulation of all elements, but especially of manganese and copper, is noted in mountain-brown podzolized soils. In mountainous chestnut-shaped soils containing little organic matter, having an alkaline reaction of the medium, an adsorption carbonate barrier is created, on which the precipitation of elements occurs. According to the content of elements, separate parts of plant associations on the studied soil types, except for the soils of the high-mountain belt, can be arranged in the following descending series: litter&gt; roots&gt; above-ground mass. The obtained data can be considered as a reference point for possible anthropogenic pollution.

ESTIMATION OF THE GEOECOLOGICAL STATE OF THE LEFT INFLOWS OF THE DNISTER RIVER (MOHYLIV-PODILSKY SITE)

The results of hydrochemical, lithogeochemical tests of surface waters, bottom sediments and soils of the coastal zone of the left inflows of Podolsk part of the Dnister river within the limits of Mogilev-Podolsky site are given. Among the investigated elements common to bottom sediments, water and soils from the banks of watercourses are Mn, Ni, Ti, V, Cr, Mo, Zr, Nb, Cu, Ba, Pb. The main attention is paid to the concentration of lead, chrome, manganese and copper in surface waters, bottom sediments and soils of the coastal zone of rivers Dnister, Zhvan, Karaets, Lyadova, Serebrya, Nemiia, Derlo. The content of the indicated elements there are less maximum permissible concentrations (MPC) of sanitary toxicological requirements and MPC of standard in water of the investigated reservoirs. In the soils and bottom sediments of the Dnister river, insignificant concentrations of most metals (at the average concentrations for river waters) were detected. The results of researches on the distribution of concentrations of chrome, lead, copper and manganesein water, bottom sediments of rivers and soils selected from their shores for better visibility are represent in the form of diagrams for each chemical element. Complex research of water, bottom sediments and soils of the coastal zone made it possible to obtain a coherent picture of the geoecological state of the rivers within their ancestral part. Taking into account that the content of the majority of investigated elements in watercourses does not exceed the MPC and answers to the average concentrations of metals in river waters of Ukraine, then it is possible to draw conclusion about the satisfactory state of reservoirs and the catchment area. It has been found that such complex and systematic studies have not been carried out in the past, so it is not possible to compare the results with the results of research in previous years. Also sharply the problem of null information costs about the geoecological state of right inflows of Dnister (the territory of the Republic of Moldova) common to both countries of the transboundary water.

Soil Lead Concentrations in Dareta Village, Zamfara, Nigeria.

Background. Acute widespread lead poisoning took place in Zamfara State, Nigeria in 2010. Over 735 children were reported dead and thousands sickened by the neurotoxin. The source was traced to artisanal gold mining and processing in the villages. An immediate medical response protocol was developed to provide oral chelation therapy to the vulnerable population. In order not to compromise the efficacy of the chelation therapy, immediate remediation of the affected villages was carried out. An over 95% reduction in soil lead levels was reported immediately after the remediation exercise.Objectives.The aim of the present study was to perform a general audit of soil lead concentrations, conducted between June and July 2013 in Dareta village (one of the most affected villages), to evaluate the soil pollution status of the village three years after the remediation exercise.Methods.Soil samples were collected from residential compounds, cultivated farmlands and other common areas. Lead contents of the samples were determined using atomic absorption spectrophotometer (Shimadzu, model AA-6800, Japan) after wet digestion. Speciation of lead in soil was done following standard analytical methods.Results.Mean soil lead concentrations for residential areas were 1029.42±98.50 mg/kg, 1523.99±201.00 mg/kg, 1404.57±141.00 mg/kg and 6724.68±84.00 mg/kg for residential compounds, market square, old grinding mills and new grinding mills, respectively. The concentrations exceeded both the Dutch target and intervention values and US Environmental Protection Agency limit for soil lead levels in residential areas. Based on the index of geo-accumulation, the ranking of intensity of lead (Pb) pollution of Dareta soils ranged from strongly polluted to extremely polluted, indicating they pose a range of moderate to very high potential ecological risk to the other components of the environment. At the current rate of accumulation, by the year 2025, soil Pb levels of Dareta common areas are expected to exceed the pre-remediation levels associated with several deaths.Conclusions.Findings of this study indicate that the problem of lead poisoning is ongoing in Dareta village. Zamfara State authorities should address the challenge through sustained periodic assessment and cleanup of affected areas. Implementation of safer mining practices should be enforced immediately.Competing Interests.The authors declare no competing financial interests

Lead content in soils and native plants near an abandoned mine in a protected area of south-western Spain: an approach to determining the environmental risk to wildlife and livestock.

A study of the impact of an abandoned lead (Pb) mine ("Las Musas"), located in SW Spain, on the contamination of the surface soil and pastures in its vicinity revealed the presence of widely distributed, high levels of Pb contamination. The total Pb concentrations in soils sampled at distances from 3 to 998 m from the mine ranged between 129 and 1053 mg/kg, when it has been reported that non-polluted soils have concentrations of 29-40 mg/kg. These exceed the maximum tolerable levels in agricultural soils for the protection of environmental and human health as established in international and regional regulations. While the concentrations of potentially bioavailable Pb in the soils also surpassed the regulatory levels, the effective bioavailable fractions were low. The Pb concentrations measured in native plants ranged from 1.70 to 129 mg/kg dry weight, with Cynosurus echinatus, Philadelphus coronarius, and Fraxinus angustifolia being the species that bioaccumulated the greatest concentrations of this metal. Estimation of the environmental risk to wildlife and livestock grazing in the studied area showed no potential toxicity for these animals.

The content and distribution of lead in the permafrost soils of the northern-taiga landscapes of Yakutia

We studied the content and nature of the distribution of lead in permafrost soils of the “Burannyi” site of the Tomtor rare-earth deposit. We explored three types of permafrost soils with low power of the soil profile: permafrost fawn-brown podzolized, permafrost fawn-brown and homogeneous non-gleyed cryozem. An experiment on lead sorption by genetic horizons of permafrost soil was constructed in the laboratory. The contents of the mobile forms of Pb in the studied soils are arranged in the ascending order: homogeneous non-gleyed cryozem < permafrost fawn-brown < permafrost fawn-brown podzolized. The experiment identified high correlation dependence of the lead content on humus values, as well as the average negative dependence on pH. Based on the constructed sorption model, it claims that the mineral horizons have the highest sorption capacity.

Distribution of contaminants in the environment and wildlife habitat use: a case study with lead and waterfowl on the Upper Texas Coast.

The magnitude and distribution of lead contamination remain unknown in wetland systems. Anthropogenic deposition of lead may be contributing to negative population-level effects in waterfowl and other organisms that depend on dynamic wetland habitats, particularly if they are unable to detect and differentiate levels of environmental contamination by lead. Detection of lead and behavioral response to elevated lead levels by waterfowl is poorly understood, but necessary to characterize the risk of lead-contaminated habitats. We measured the relationship between lead contamination of wetland soils and habitat use by mottled ducks (Anas fulvigula) on the Upper Texas Coast, USA. Mottled ducks have historically experienced disproportionate negative effects from lead exposure, and exhibit a unique nonmigratory life history that increases risk of exposure when inhabiting contaminated areas. We used spatial interpolation to estimate lead in wetland soils of the Texas Chenier Plain National Wildlife Refuge Complex. Soil lead levels varied across the refuge complex (0.01-1085.51 ppm), but greater lead concentrations frequently corresponded to areas with high densities of transmittered mottled ducks. We used soil lead concentration data and MaxENT species distribution models to quantify relationships among various habitat factors and locations of mottled ducks. Use of habitats with greater lead concentration increased during years of a major disturbance. Because mottled ducks use habitats with high concentrations of lead during periods of stress, have greater risk of exposure following major disturbance to the coastal marsh system, and no innate mechanism for avoiding the threat of lead exposure, we suggest the potential presence of an ecological trap of quality habitat that warrants further quantification at a population scale for mottled ducks.

Temporal effect of MgO reactivity on the stabilization of lead contaminated soil

Elevated soil lead (Pb) concentrations are a global concern owing to the toxic effects of this heavy metal. Solidification/stabilization (S/S) of soils using reagents like Portland cement (PC) is a common approach for the remediation of Pb contaminated sites. However, it has been reported that under long-term field conditions, the performance of PC treatments can diminish significantly. Therefore, novel reagents that provide longer-term stabilization performance are needed. In this study, four magnesium oxide (MgO) products of different reactivity values were applied (5 wt%) to a Pb contaminated clayey soil. The short-term (1–49 days) and long-term (25–100 years) temporal stabilization effects were investigated by laboratory incubation and accelerated ageing methods, respectively. The concentration of Pb in Toxicity Characterization Leaching Procure (TCLP) leachate was ~14 mg/L for the untreated soil; ~1.8 times higher than the TCLP regulatory level (5 mg/L). Only one day after treatment with MgO, the leachate concentration was reduced to below the regulatory level (a reduction of 69.4%–83.2%), regardless of the MgO type applied. However, in the long-term accelerated ageing experiments, only treatments using the most reactive MgO type could provide leachate concentrations that were consistently below the TCLP threshold throughout the 100 years of simulated ageing. The soil treated with the MgO of lowest reactivity was the first to exceed the regulatory level, at simulated year 75. It is thus demonstrated that MgO reactivity has a significant effect on its long-term effectiveness for contaminated soil stabilization. This is attributed to differences in their specific surface area and readiness to carbonate, which may facilitate the immobilization of Pb in the long term. It is also noteworthy that compared to PC, reactive MgO is more environmentally friendly owing to lower energy consumption and reduced CO2 emissions during its manufacture.

Metal-Tolerant Fungal Communities Are Delineated by High Zinc, Lead, and Copper Concentrations in Metalliferous Gobi Desert Soils.

The soil fungal ecology of the southern Gobi region of Mongolia has been little studied. We utilized the ITS1 region from soil DNA to study possible influences soil metal concentrationson soil fungal community variation. In the sample network, a distinctive fungal community was closely associated with high zinc (Zn), lead (Pb), and copper (Cu) concentrations. The pattern of occurrence suggests that high metal concentrations are natural and not a product of mining activities. The metal-associated fungal community differs little from the "normal" community in its major OTUs, and in terms of major fungal guilds and taxa, and its distinctiveness depends on a combination of many less common OTUs. The fungal community in the sites with high metal concentrations is no less diverse than that in areas with normal background levels. Overall, these findings raise interesting questions of the evolutionary origin and functional characteristics of this apparently "metal-tolerant" community, and of the associated soil biota in general. It is possible that rehabilitation of metal-contaminated mined soils from spoil heaps could benefit from the incorporation of fungi derived from these areas.

Analysis of lead contamination in soil (case: Pesarean village, Tegal district area)

The smelting of metal and used battery which was carried out in Pesarean Village, Tegal District has resulted a huge amount of openly waste that has not been processed properly. This waste contains heavy metal such as lead that counted as hazardous and toxic waste materials. It can affect the quality of environment not only polluting the air but also the soil and groundwater. The aims of this study were to analyze the effect of lead concentration on the environment, especially soil and groundwater. The method that used in this study was quantitative methods with analyzing secondary data, literature and previous research review. The results showed that in 2012 concentration of lead in soil of waste disposal area reached 14,343 ppm, and in 2015, the highest concentration was in residential and dumpsite area with concentration 398,489 ppm. In groundwater, lead concentration was still below the water quality standard.

DETERMING LEAD IN SOIL BY EXTRACTION-PHOTOMETRIC IN CAO LANH CITY, DONG THAP PROVINCE

This paper is to identify lead content in soil by extraction-photometric method and using non-polar solvents (CHCl3) to extract complex of lead (II) -dithizone. The optimal conditions of extraction process of lead(II) dithizonate have been identified: pH is from 8.5 to 10,0; the maximum wavelength of lead(II) dithizonate compound is 520nm (λmax = 520 nm); absorbance of the solution in compliance with the Bougher-Lambert-Beer law is in wide range from 0.02 to 0.1 mg/l.

Probabilistic health risk assessment of heavy metals in honey, Manihot esculenta, and Vernonia amygdalina consumed in Enugu State, Nigeria.

Honey is a nutritive fluid product of bees with an array of pharmacological/medicinal effects. As a natural product from honeybees, honey is regarded to be safe and free from any contaminants. Cassava tuber (Manihot esculenta)-based meal, Vernonia amygdalina (bitter leaf soup), and honey are common local cuisine in Nigeria. This is a human health risk assessment of heavy metals associated with the consumption of honey (Apis mellifera scutellata), cassava (Manihot esculenta), and bitter leaf (Vernonia amygdalina) in Enugu State, Nigeria. Concentrations of lead (Pb), Cd, As, Cu, Ni, Mn, Fe, Cr, and Fe in honey, soil, Manihot esculenta, and Vernonia amygdalina were determined using an atomic absorption spectrophotometer (AAS). The principal component analysis (PCA) was performed as a factor reduction technique among 12 factors (3 locations against 4 sources of heavy metals). The mean concentration of metals in honey, soil, Manihot esculenta, and Vernonia amygdalina ranged from 0.001 to 4.28 mg kg-1, from 0.0026 to 170.52 mg kg-1, from 0.012 to 80.63 mg kg-1, and from 0.0016 to 126.48 mg kg-1, respectively. Pb showed the highest carcinogenic risk with values of 3.18E-04-1.43E-01 in Vernonia amygdalina and 1.69E-04-3.47E-04 in Manihot esculenta for adults and children, respectively. In honey, Cd showed the highest carcinogenic risk with values of 1.26E-02-1.07E-01. About 51.5% of total cancer risk (TCR) was below 1E-04. Consumption of honey, Vernonia amygdalina, and Manihot esculenta in some urban parts of Enugu may pose some adverse health effects.

Heavy Metals in Agricultural Soils of the Lihe River Watershed, East China: Spatial Distribution, Ecological Risk, and Pollution Source.

Concentrations of cadmium, chromium, copper, nickel, lead, and zinc in agricultural soils at 32 sites in the Lihe River Watershed of the Taihu region, East China, and their potential ecological risks and possible sources were investigated. Enrichment factor analysis demonstrated enrichment in the order Cd > Pb > Zn > Cu > Ni > Cr. The potential ecological risk index and risk assessment code analyses indicated that, of the metals studied, Cd posed the most significant ecological risk in the study area. Statistical analyses, GIS mapping, and enrichment factor analysis suggested that Cd, Pb, Cu, and Zn were derived mainly from anthropogenic sources, including agricultural, industrial, and vehicular emissions, while Cr and Ni were mainly from natural sources. Positive matrix factorization revealed that Cd, Cr, Cu, Ni, Pb, and Zn were sourced from industrial and vehicular emissions (73.7%, 21.3%, 71.4%, 20.3%, 75.0%, and 62.2%, respectively), the agricultural sector (26.3%, 36.3%, 6.8%, 38.9%, 15.7%, and 6.9%, respectively), and parent materials (0%, 42.4%, 21.8%, 40.8%, 9.2%, and 30.9%, respectively). It was recommended that strategies be implemented to reduce industrial point-source pollution.

Heavy metal accumulation by selected plant species along the national highway: a case study of Udaipur, Rajasthan, India

ABSTRACTA detailed research was conducted to find out the heavy metal accumulation by plant species at the roadside. Bioconcentration, bioaccumulation and translocation factors were estimated in 10 individuals of each investigating plant species. The plant and soil samples used in the research were collected along the National Highway-76 from Chittorgarh to Udaipur, Rajasthan, India. The concentration of cadmium and lead in roadside soil, plant roots, stems and leaves shows a correlation. The highest bioconcentration factor of Cd and Pb was 0.22 ± 0.04 and 0.13 ± 0.02 estimated in Bougainvillea spectabilis Willd. The highest translocation factor of Cd was 1.30 ± 0.50 in Pongamia pinnata L., and the highest translocation factor of Pb was 1.63 ± 0.45 estimated for Nerium oleander L. The average concentrations of Cd and Pb were 11.35 ± 1.60 and 223.70 ± 68 mg kg−1 in investigated roadside soil. The average concentrations of accumulated Cd and Pb in B. spectabilisWilld. were 2.38 ± 0.49, 1.97 ± 0.51, 3.07 ± 0.78 and 29.34 ± 7.82,18.96 ± 5.62, 37.75 ± 12.93 mg kg−1 in roots, stems and leaves, respectively. The decreasing order of bioaccumulation factor of cadmium in plants was B. spectabilis Willd.>Butea monosperma (Lam.) Taub>Calotropis procera (Ailton) Dryand>N. oleander L.>P. pinnata L. The decreasing order of bioaccumulation factor of lead in plants was B. spectabilis Willd.>P. pinnataL.>B. monosperma (Lam.) Taub>C. procera (Ailton) Dryand>N. oleander L. The B. spectabilis Willd. was identified as a rhizofiltration tool of heavy metals such as Cd and Pb with higher bioconcentration factor. P. pinnata L. for Cd and N. oleander L. for Pb were revealed for phytoextraction technology with high translocator factor to accumulate and eliminate these toxic elements from soil.

The response of wetland quality indicators to human disturbance indicators across the United States

We analyzed data from 1138 wetland sites across the conterminous United States (US) as part of the 2011 National Wetland Condition Assessment (NWCA) to investigate the response of indicators of wetland quality to indicators of human disturbance at regional and continental scales. The strength and nature of these relationships in wetlands have rarely been examined over large regions, due to the paucity of large-scale datasets. Wetland response indicators were a multimetric index of vegetation condition (VMMI), percent relative cover of alien plant species, soil lead and phosphorus, and water column total nitrogen and total phosphorus. Site-level disturbance indices were generated from field observations of disturbance types within a circular 140-m radius area around the sample point. Summary indices were calculated representing disturbances for ditching, damming, filling/erosion, hardening, vegetation replacement, and vegetation removal. Landscape-level disturbance associated with agricultural and urban land cover, roads, and human population were based on GIS data layers quantified in 200, 500, and 1000-m circular buffers around each sample point. Among these three buffer sizes, the landscape disturbance indicators were highly correlated and had similar relationships with the response indictors. Consequently, only the 1000-m buffer data were used for subsequent analyses. Disturbance-response models built using only landscape- or only site-level disturbance variables generally explained a small portion of the variance in the response variables (R2 < 0.2), whereas models using both types of disturbance data were better at predicting wetland responses. The VMMI was the response variable with the strongest relationship to the disturbances assessed in the NWCA (national model R2 = 0.251). National multiple regression models for the soil and water chemistry and percent alien cover responses to disturbance indices were not significant. The generally low percentage of significant models and the wide variation in predictor variables suggests that stressor-response relationships vary considerably across the diversity of wetland types and landscape settings found across the conterminous US. Logistic regression modeling was more informative, resulting in significant national and regional models predicting site presence/absence of alien species and/or the concentration of lead in wetland soils above background.

Concentration of Heavy Metals in Soil around Dumpsites in Jimeta and Ngurore, Adamawa State, Nigeria

Rapid urbanization and industrialization in developing countries have been associated with production and deposition of hazardous wastes in the soil environments. Heavy metals are major components of these wastes and have been implicated in several metal-related diseases and food poisoning in man. This study examined the concentration of Iron (Fe), Lead (Pb), Copper (Cu), Chromium (Cr), and Cadmium (Cd) heavy metals in soil near dumpsites of Jimeta and Ngurore, Yola North Local Government Areas (LGAs), Adamawa State. Soil samples from 0-20cm layer depth were collected in triplicates and analyzed using atomic absorption spectrophotometer (AAS). Results reveal that Fe, Pb, Cu and Chromium were detected, while Cadmium was found to be below the limit of detection. The mean concentration of the exchangeable cation in mg/kg in soil at Jimeta sites were: Fe (31.4 mg/kg) &gt;Pb (0.92 mg/kg) &gt; Cu (0.34 mg/kg) &gt; Cr (0.11 mg/kg) &gt;Cd (below limit of detection), while the mean concentration of the heavy metals in soil at Ngurore sites were: Fe (32 mg/kg) &gt;Pb (0.83 mg/kg) &gt; Cu (0.28 mg/kg) &gt; Cr (0.07 mg/kg) &gt;Cd (below limit of detection), respectively. Iron (Fe) was the most abundant element in both sites, followed by Pb. Heavy metal concentrations in soil followed the order of Fe&gt;Pb&gt;Cu&gt;Cr&gt;Cd, respectively. The paired T-test analyses for concentration of Cr, Fe, and Pb in soil nearthe two dumpsites show that there were statistically significant differences in the concentration levels of Cr, Fe, and Pb, while Cu showed no statistically significant difference between the two dumpsites. However, all the metals detected were below the permissible limit of WHO international standard with the exception of Pb whose concentration was above maximum permissible concentration (MPC). Persistent heavy metals accumulation in soils near these dumpsites may lead to increase uptake by vegetables grown near the dumpsites and this may pose a threat to its quality and safety and ultimately human health. The need to replace open dumpsites with well-designed landfills is advised.

Lead Content and Mobility in Soils of the Republic of Tatarstan under Different Land Use Types

Lead Content and Mobility in Soils of the Republic of Tatarstan under Different Land Use Types

Influence of edaphic conditions and nitrogen fertilizers on cadmium and zinc phytoextraction efficiency of Noccaea caerulescens

The success of cadmium phytoextraction operations with Noccaea caerulescens varies by a factor of 70 between sites of trials. However, soil factors driving the efficiency of cadmium (Cd) and zinc (Zn) phytoextraction are still poorly understood, as are the effects of nitrogen fertilizers. We studied biomass production and Cd and Zn uptake by two contrasting populations of N. caerulescens, Ganges (metallicolous) and Wilwerwiltz (non-metallicolous) grown in pots on a range of 24 field contaminated soils for 20 weeks. The addition of KNO3 and NH4NO3 fertilizers was also tested. Using model averaging of multiple regression models, we show that the major drivers of N. caerulescens growth are physical soil factors such as organic matter and soil bulk density while trace metal accumulation mainly relies on soil Cd and Zn exchangeable concentrations. We confirm the negative effect of soil copper (Cu) on growth, even at exchangeable concentrations below 30 mg kg−1, and therefore on uptake efficiency, while increasing soil lead (Pb) content was related to increased biomass probably due to a protective effect against soil pathogens. Finally, there is a small positive effect of nitrogen fertilization on biomass production only in soils with low initial nitrogen content (under 25 μg g−1 NO3−), while above this value, the positive impact of initial nitrogen content is offset by lower shoot Cd and Zn concentrations. Our data bring substantial information regarding the physico-chemical properties to ensure N. caerulescens growth: a soil bulk density under 1.05 kg/dm3, organic matter above 7% and pH under 7.5. We show that phytoextraction efficiency is maximal for moderate soil contamination in Cd (2–10 mg kg−1) and Zn (300–1000 mg kg−1).