Lead Concentrations In Soil Research Articles

Assessing Levels of Lead Contamination in Soil and Predicting Pediatric Blood Lead Levels in Tema, Ghana

Background. Tema, Ghana's main industrial city, has many areas that are suspected to be contaminated by lead. Elevated lead levels can affect, among many other issues, mental development, kidney function and blood chemistry. Children are particularly at risk. Objectives. The objective of this study was to determine the concentration of lead in soil from selected sites in Tema and how these levels relate to local pediatric blood lead predictions. Methods. A total of 47 surface soil samples were taken from 9 different sites. Energy dispersive X-ray technique was employed to determine the levels of lead. Pediatric blood lead levels were estimated using the Integrated Exposure Uptake Bio-Kinetic Model For Lead in Children, developed by the U.S. EPA. Results. The study revealed that the selected sites are highly contaminated by lead. In particular, the concentration of Pb in soil at a used lead acid battery recycling facility exceeded regulatory limits for industrial soil as set by the U.S. EPA. The model for predicting concentrations of lead in the blood of age-specific children showed extremely high probabilities of BLLs exceeding regulatory limits. Conclusions. Based on the results of soil testing, sites that were expected to reveal lead exposure positively demonstrated high levels of contamination, in some areas exceeding U.S. and other national regulatory limits. This information is expected to help authorities make informed clean-up decisions.

Spatial Variation of Soil Lead in an Urban Community Garden: Implications for Risk‐Based Sampling

Soil lead pollution is a recalcitrant problem in urban areas resulting from a combination of historical residential, industrial, and transportation practices. The emergence of urban gardening movements in postindustrial cities necessitates accurate assessment of soil lead levels to ensure safe gardening. In this study, we examined small-scale spatial variability of soil lead within a 15 × 30m urban garden plot established on two adjacent residential lots located in Detroit, Michigan, USA. Eighty samples collected using a variably spaced sampling grid were analyzed for total, fine fraction (less than 250 μm), and bioaccessible soil lead. Measured concentrations varied at sampling scales of 1-10m and a hot spot exceeding 400ppm total soil lead was identified in the northwest portion of the site. An interpolated map of total lead was treated as an exhaustive data set, and random sampling was simulated to generate Monte Carlo distributions and evaluate alternative sampling strategies intended to estimate the average soil lead concentration or detect hot spots. Increasing the number of individual samples decreases the probability of overlooking the hot spot (type II error). However, the practice of compositing and averaging samples decreased the probability of overestimating the mean concentration (type I error) at the expense of increasing the chance for type II error. The results reported here suggest a need to reconsider U.S. Environmental Protection Agency sampling objectives and consequent guidelines for reclaimed city lots where soil lead distributions are expected to be nonuniform.

Thirty-Year Manuring and Fertilization Effects on Heavy Metals in Black Soil and Soil Aggregates in Northeastern China

To evaluate the effects of thirty years of manure and chemical fertilizer applications on metal accumulations in soil and soil aggregates, fresh soils were separated by wet sieving into four aggregate fractions and heavy-metal concentrations in soil and aggregates were determined. The soil organic carbon (SOC) concentration in microaggregates ranged from 20.2 to 39.6 g carbon (C) kg−1, which was significantly greater than those in the other fractions. The proportion of heavy metals in small macroaggregates and the silt + clay fraction accounted for 45.5 ± 10.6% and 35.8 ± 14.1% of the total amount in soil, respectively, which might be due primarily to their greater mass percentages in soil. Both chemical fertilizer and manure significantly stimulated iron (Fe) and zinc (Zn) accumulation; horse manure also increased copper (Cu), lead (Pb), and chromium (Cr) concentration in bulk soils as compared with the control. The results also indicated that heavy-metal distribution in aggregates was not controlled by SOC but possibly by soil clay.

Implications of different residential lead standards on children's blood lead levels in France: Predictions based on a national cross-sectional survey

Despite the dramatic reductions in children's blood lead levels (BLLs), there is considerable evidence that low-level lead exposure is associated with intellectual deficits and behavioral problems, without apparent threshold. There are limited data, however, about the contribution of residential sources of lead to contemporary children's blood lead levels. The aim of this study is to calculate the contributions of residential sources of lead to assess the potential impact of setting new standards for lead levels in residential dust, soil and water. We enrolled 484 French children aged from 6 months to 6 years, and collected data on social, housing and individual characteristics. Lead concentrations in blood and environmental samples (water, soils, and dusts) were measured using inductively coupled plasma mass spectrometry. Data were analyzed using a multivariate generalized additive model accounting for the sampling design and the sampling weights. We found that exceedingly low concentrations of lead in dust, soil and water were significant predictors of children's BLLs, after adjustment for potential confounding variables. Lead-contaminated floor dust was the main source of lead in blood. BLLs (GM: 14μg/L) increased by 65%, 13%, 25%, and 5% when lead content in floor dust, loose soil, hard soil and water increased from their 25th percentile to their 95th percentile, respectively. We also observed that the steepest increase in BLLs occurred at the lowest levels of lead-contaminated floor dust, which indicates that lead contamination should be kept as low as possible. Impact of different possible standards on children's BLLs was also tabulated and indicated that unless standards are set low, they will only benefit a small proportion of children who have the highest exposures.

Fractionation of Selected Heavy Metals in Agricultural Soils / Frakcjonowanie Wybranych Metali Ciężkich W Glebach Uprawnych

Abstract The content of trace elements in soils varies widely and their mobility and availability depends not only on the total content but also on the form of in which these elements occur. The aim of this study was to determine the total content of nickel, lead, zinc and copper in soils used for agriculture, and assess the mobility and phytoavailability of these metals against a background of physical and chemical properties of these soils. In samples taken from three soil profiles (Phaeozem and 2 Fluvisols) the contents of Ni, Pb, Zn and Cu were determined using atomic absorption spectroscopy in the solutions obtained according to the protocol of modified BCR sequential extraction procedure supplemented with aqua regia digestion. The total content of the analyzed metals in most cases corresponded to the natural values, often not exceeding the geochemical background level. It was only in the one profile of the Fluvisols (Endogleyic Fluvisol) that a higher concentration of zinc and lead was noticed (especially in the surface horizon), slightly exceeding the legal limit. Among the studied metals the lowest phytoavailability was characterized by copper (exchangeable forms on average 4.73% of the total), and the highest by zinc (11.49%). Nickel was the most permanently bound with soil solid phase, and its content in the residual fraction reached 84.46% of the total. Approximately a half of the total lead content was determined as a fraction bound with iron and manganese oxides, while in the case of this metal a significant role in binding of this metal was playing organic matter (fraction bound with organic matter and sulphides - an average of 27.5%). Significant role in the binding of all investigated metals was credited to iron and manganese compounds.

English

Heavy metals pollution is considered as one of the most dangerous environmental problems in agricultural soil, particularly neighboring mining sites. Phytoremediation based on green plants use seems to be an interesting biological solution to detoxify these soils. This study focuses especially on heavy metals effects on Rosmarinus officinalis L. morphological and growth parameters. The site of our research is “Bougrine” mine which represents different zinc, lead and cadmium amounts by geological layers. In opposite to amounts obtained by previous studies made for mining exploration, we thought that zinc content was more important at transition zone than Cenomanian Turonian level. Nevertheless, this element is not the most determinant in plant growth and its morphological parameters. Moreover, R. officinalis L. volume and vigor decreased when soil’s heavy metals content increases. However, this reduction is more related to soil lead content. Despite this decrease, we do not observe any visual phytotoxicity symptom. This aromatic and medicinal species, belonging to Lamiaceae family, could be used as alternative crops in polluted soils. Keywords: Rosmarinus officinalis L., zinc, lead, growth, photosynthesis, “Bougrine” mine African Journal of Biotechnology Vol. 12(2), pp. 150-161

Assessment of Lead, Zirconium and Iron Concentration in Soils in Parts of Jos Plateau, North Central Nigeria

Thirty soil samples from Rayfield, Bukuru and environs on the Jos Plateau were analysed for lead (Pb), Zirconium (Zr) and Iron(Fe) using the X-ray fluorescence (XRF) analytical method, with the aim of determining the extent to which the long history of mining, and other suficial processes have affected the soils of the study area. The distribution of the analysed elements (Pb, Zr, Fe) were evaluated to monitor potential threats to human health and the natural ecosystem by comparing the determined concentrations of these elements (Pb, Zr, Fe) with concentrations in uncultivated and unmined areas as controls.Mean concen- trations of 223.67ppm was obtained for Pb; 425.53ppm for Zr and 56208.7ppm for Fe as against 17ppm, 270ppm and 21000ppm for Pb, Zr, and Fe respectively inunmined and uncultivated soils.A calculation of anthropogenic factor (AF) and Index of geo-accumulation (Igeo) indicated Pb, Zr and Fe contaminations (Pb moderate to high, Zr and Fe low to moderate contamina- tions) in soils of the study area. These values can be used as guidelines for ensuring the preservation of environmental integrity of the study area.

Contents of nickel, zinc, copper and lead in agricultural soils of the plains in the northwestern part of the Republic of Srpska

Contents of nickel, zinc, copper and lead in agricultural soils of the plains in the northwestern part of the Republic of Srpska

Sources and risk factors for lead exposure in indigenous children of the Peruvian Amazon, disentangling connections with oil activity

In the Corrientes river basin, Peruvian Amazon, lead exposure among indigenous communities was first reported in 2006. To address controversy regarding the main source of exposure, this study aimed to identify the sources and risk factors for lead exposure among children from the communities in question, and to clarify the potential relationship with oil activity. This cross-sectional study was conducted in six communities. Participants were children aged 0-17 years and their mothers. Data collection included blood lead levels (BLLs) and hemoglobin determination, a questionnaire on risk factors and environmental sampling. We used age-stratified multivariate regression models, with generalized estimating equation to account for correlation within households. Twenty-seven percent of the children had BLLs ≥10 μg/dl. Mother's BLLs ≥10 μg/dl, playing and chewing lead scraps, fishing ≥three times/week, and living in highly oil-exposed communities increased the risk of having BLLs ≥10 μg/dl. Lead concentrations in sediment, soil, dust, and fish samples were below reference values. Mother's BLLs ≥10 μg/dl, playing and chewing lead scraps to manufacture fishing sinkers were the most important risk factors for children's BLLs ≥10 μg/dl. The connection with oil activity appears to be through access to metal lead from the industry's wastes.

Geostatistical evaluation of lead and zinc concentration in soils of an old mining area with complex land management

This study is aimed at detailed statistical and geostatistical investigation of lead and zinc concentration in an old mining area located in the eastern part of the Upper Silesian Industrial Region. This area is rich in lead and zinc ores whose intense extraction dates back to the tenth century ad. The complexity of the area results from historical and current mining activities, as well as from a variety of different types of land management and complex geological conditions. Almost 1,000 collected soil cores were divided into two subsets: those collected at the depth of up to 20 cm and the those collected at the depth from 40 to 60 cm. Extensive analyses considered geological substrata in terms of spatial variability and spatial distributions, the type of land management, geoaccumulation indexes and enrichment factors. Lead and zinc concentration was several times higher on depths ranging from 40 to 60 cm beneath the soil surface than in the 20-cm topsoil. The results showed that clearer spatial dependence was observed for deeper soil layers then for the topmost ones, especially near mines where anthropogenic factors predominated over lithogenic ones. Weak spatial dependence was accompanied by high values of the geoaccumulation index. The lowest concentrations of pollution with geoaccumulation index below 0 and enrichment factor up to 5 observed in the forest were caused by low anthropogenic pressure and the presence of sandy soils, less capable of accumulating heavy metals.

Lead exposure from soil in Peruvian mining towns: a national assessment supported by two contrasting examples

To estimate the population of Peru living in the vicinity of active or former mining operations that could be exposed to lead from contaminated soil. Geographic coordinates were compiled for 113 active mines, 138 ore processing plants and 3 smelters, as well as 7743 former mining sites. The population living within 5km of these sites was calculated from census data for 2000. In addition, the lead content of soil in the historic mining town of Cerro de Pasco and around a recent mine and ore processing plant near the city of Huaral was mapped in 2009 using a hand-held X-ray fluorescence analyser. Spatial analysis indicated that 1.6 million people in Peru could be living within 5km of an active or former mining operation. Two thirds of the population potentially exposed was accounted for by 29 clusters of mining operations, each with a population of over 10 000 each. These clusters included 112 active and 3438 former mining operations. Soil lead levels exceeded 1200mg/kg, a reference standard for residential soil, in 35 of 74 sites tested in Cerro de Pasco but in only 4 of 47 sites tested around the newer operations near Huaral. Soil contamination with lead is likely to be extensive in Peruvian mining towns but the level of contamination is spatially far from uniform. Childhood exposure by soil ingestion could be substantially reduced by mapping soil lead levels, making this information public and encouraging local communities to isolate contaminated areas from children.

LEAD TOXICITY: CONSEQUENCES AND INTERVENTIONS IN AN INTENSIVELY MANAGED (GYPS COPROTHERES) VULTURE COLONY

The National Zoological Gardens of South Africa (NZG) is involved in the ex situ conservation of Gyps coprotheres, the Cape Griffon vulture (CGV) and houses 24 birds in a 100-yr-old aviary. Following the death of one vulture with high liver lead concentrations, an investigation was launched to ascertain the source(s) and consequences of lead toxicity in this breeding colony. Whole blood from 24 CGV, paint from the enclosure, water, and soil sampled at various locations within the enclosure were evaluated for their lead concentration, and data were gathered from NZG's medical records. The lead concentration in the paint, water, and enclosure soil was 5,100 microg/g, 0.5 microg/dl, and 72.48 +/- 21.83 microg/g, respectively. The whole-blood lead concentrations were 56.58 +/- 11 microg/dl. The breeding history of six pairs within the contaminated enclosure since 2002 showed 45 eggs laid, of which 44% were infertile and 24% successfully reared. The medical records revealed evidence of osteodystrophy despite adequate nutrition. As intervention measures, six birds were treated with Ca2+EDTA and the topsoil inside the enclosure was replaced. As a result, the lead concentration in the enclosure soil dropped to 14.74 +/- 14.39 microg/g, and the whole-blood lead concentrations declined to 42.75 +/- 11.64 microg/dl. It was concluded that lead concentrations in whole blood in excess of 100 microg/dl leads to clinical signs of lead toxicity in the CGV. Lower levels appear to interfere mainly with reproductive potential.

Determination of lead in soil at a historical mining and smelting site using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was used to determine lead (Pb) concentration in soil and tailing samples collected from a historical mining and smelting area. The Pb emission line at 405.781 nm was found to have the strongest intensity and highest linearity with concentration. It was further normalized by the Al emission line (394.401 nm), and a relationship between the peak area ratio (Pb/Al) and Pb concentration was established to determine Pb concentration of unknown samples. The Pb concentration was the highest at the former smelter site and unremediated mine-tailing areas, indicating that severe Pb contamination is still occurring. The Pb concentration decreased with increasing distance from the two major source areas (smelting and mine-tailing sites), although all samples exceeded the 400 mg/kg standard set by the United States Environmental Protection Agency. The limit of detection (LOD) for Pb was found to be 48 mg/kg, and the Pb concentrations determined by LIBS were in reasonable agreement with concentrations obtained by inductively coupled plasma mass spectroscopy (ICP-MS; within 26%). When Pb concentrations were determined by calibration-free (CF)-LIBS, which does not require standard soil samples and dilution, both LIBS and ICP-MS were also in good agreement, suggesting that the CF-LIBS method can be used to determine Pb concentrations in highly contaminated soil samples. In addition to Pb, other metal emission lines from LIBS spectra were used to classify soil samples among the sites using a principal component analysis (PCA) method, showing a distinct difference in metal distribution between sites that are heavily contaminated by two major sources.

Concentration and Spatial Distribution of Lead in Soil Used for Ammunition Destruction

Studies on heavy metal contamination in soils used for ammunition disposal and destruction are still emerging. The present study aimed to evaluate the contamination level and spatial distribution of lead in disposal and destruction areas. This site was used for ammunition disposal and destruction activities for 20 years. The ammunition destruction site (1,296 ha), a sampling system that followed a sampling grid (5 m × 5 m) with 30 points was adopted and samples were collected at the following five depths with a total of 150 samples. During the collection procedure, each sampling grid point was georeferenced using a topographic global positioning system. Data were validated through semivariogram and kriging models using Geostat software. The results demonstrated that the average lead value was 163 mg kg(-1), which was close to the investigation limit and the contamination levels were higher downstream than upstream. The results showed that there was lead contamination at the destruction site and that the contamination existed mainly at the surface layer depth. However, high lead concentrations were also found at deeper soil depths in the destruction area due to frequent detonations. According to the planimetry data, the areas that require intervention significantly decreased with increasing depths in the following order: 582.7 m(2) in the 0-20 cm layer; 194.6 m(2) in the 20-40 cm layer; 101.6 m(2) in the 40-60 cm layer; and 45.3 m(2) in the 60-80 cm layer.

Microbial community structure in the rhizosphere of Sophora viciifolia grown at a lead and zinc mine of northwest China

Understanding the effects of heavy metal contamination on microbial activity is important for developing strategies to reclaim sites disturbed by industrial activities. In this study, we investigated arbuscular mycorrhizal (AM) fungi and bacteria associated with Sophora viciifolia growing at a lead and zinc mine in Qinling Mountain, China. Specifically, we measured the extent of AM fungal root colonization, examined microbial community structure by PCR-denaturing gradient gel electrophoresis (PCR-DGGE), and identified the dominant microorganisms. We also measured the amount of glomalin-related soil protein (GRSP) and the association of GRSP with heavy metal ions. We found that AM root colonization decreased, but total GRSP increased with the increase of the lead concentration in soil. The Shannon–Wiener Index (H′) of the AM fungal community showed a significant negative correlation with the available lead concentration (r=0.92, P=0.009). Bacterial community H′ was also negatively correlated with the total and available lead concentrations in the soil (r=0.97, P=0.007 and r=0.92, P=0.025 for total and available lead, respectively). Both, AM fungal and bacterial community structures differed significantly between sites along the pollution gradient. The specific distributions of the two kinds of organisms indicated their differing tolerances to heavy metal. The dominant AM fungi were identified as Glomeraceae, whereas the dominant bacteria belonged to Proteobacteria. The amount of lead bound to GRSP varied from 3.3 to 172.5mgkg−1, which positively correlated with total and available soil lead concentration (r=0.99, P<0.000 and r=0.93, P=0.020 for total soil lead and available soil lead concentration, respectively), thus reducing the bioavailability of heavy metal ions.

Soil Lead Distribution and Environmental Justice in the Phoenix Metropolitan Region

Abstract In this study, we investigate socioeconomic inequities related to the spatial distribution and potential exposure from lead in the rapidly urbanizing region of Phoenix, AZ. We use soil lead concentrations from 200 samples collected across Phoenix as indicators of potential lead exposure, and compare them with population characteristics aggregated at the census tract level from the 2000 census, using regression and spatial autocorrelation. Percent Hispanic and percent renters are the two major regressors for lead distribution, which indicates that wealth is a weaker predictor of inequitable lead exposure than race/ethnicity and housing tenure in metropolitan Phoenix. Inequitable distribution of soil lead, likely from lead paint, reflects diminished social power, authority, and funds of neighborhoods with a high percentage of nonwhite residents living in rental housing to mitigate the potential hazard of historic lead-based paint.

Groundwater Contamination at Waste Disposal Sites at Ibadan, Nigeria

A study was carried out to determine groundwater contamination levels on waste disposal sites of Ibadan city center in Nigeria. The surface areas of the sites vary between 23.5ha to 3.5acres. The field investigation included surface geological, hydrogeochemical and geochemical studies on the study area. Water samples were collected at 18 points. Three observation wells were dug in front of the open waste disposal site. Soil samples from these observation wells were collected at 15, 35 and 75 cm depths, and some heavy metals were analyzed. The results obtained show that concentrations of lead, copper and zinc in soil at the depth of 150 cm decreased with distance from the waste disposal site. The closest well to the waste site showed higher contamination than the control sites. Strictly speaking, use of groundwater drawn from wells located in proximity of the waste dumping sites should be avoided. If precautions are not taken, these contaminants may well spread with groundwater and pollute other soil resources used for agriculture in Ibadan.

Sources, lability and solubility of Pb in alluvial soils of the River Trent catchment, U.K.

Alluvial soils are reservoirs of metal contaminants such as Pb that originate from many different sources and are integrated temporally and spatially through erosional and depositional processes. In this study the source, lability and solubility of Pb were examined in a range of alluvial soils from the middle and lower River Trent and its tributary the River Dove using Pb isotope apportionment and isotopic dilution. All samples were collected within 10m of the river bank to represent the soil that is most likely to be remobilised during bank erosion. Paired samples were taken from the topsoil (0–15cm) and subsoil (35–50cm) to assess differences with depth. Lead concentrations in soil ranged from 43 to 1282mg/kg. The lability of soil Pb varied between 9 and 56% of total metal concentration whilst Pb concentrations in pore water varied between 0.2 and 6.5μg/L. There was little difference in the % Pb lability between paired top and sub soils, possibly because soil characteristics such as pH, iron oxides and clay content were generally similar; a result of the recycling of eroded and deposited soils within the river system. Soil pH was found to be negatively correlated with % Pb lability. Source apportionment using 206Pb/207Pb and 208Pb/207Pb ratios showed that the isotopic ratios of Pb in the total, labile and solution pools fitted along a mixing line between Broken Hill Type (‘BHT’) Pb, used as an additive in UK petrol, and the local coal/Southern Pennine ore Pb. Various anomalies were found in the Pb isotopes of the bankside alluvial soils which were explained by point source pollution. Statistically significant differences were found between (i) the isotopic composition of Pb in the total soil pool and the labile/solution pools and (ii) the isotopic composition of Pb in the labile and solution pools, suggesting an enrichment of recent non-Pennine sources of Pb entering the soils in the labile and solution pools.

Effect of the GWDA compost and PRP sol fertilisation on the total content of nickel, manganese and lead and their soluble forms in soil

A field experiment was carried out at the Agricultural Experimental Station in Lipnik near Stargard Szczecinski in 2008-2009. It was set up on soil classified as soil quality class IVa and good rye complex (5). In the study, the GWDA compost produced at the Municipal Sewage Treatment Plant in Stargard Szczecinski was used. This compost was characterised by neutral reaction (pH H2O 7.15). The total content of heavy metals, which limits its possible use as fertiliser, did not exceed the standards given in the Regulation of the Minister of Agriculture and Rural Development (Official Journal of Law No. 119, item 765 of 2008). Compost doses were determined based on the total nitrogen content. It was assumed that 100 kg N ha –1 was added to soil with the 1 st dose, 200 kg N with the 2 nd dose, and 300 kg N with the 3rd dose. The experiment was carried out in two series: with and without addition of the active substance PRP SOL. In autumn 2007, respective compost doses were introduced into soil on established plots according to the experimental design. The active substance PRP SOL was applied at a 150 kg ha –1 dose before sowing or seeding test plants. The whole experimental area was fertilised with multicomponent fertiliser Polifoska 6 in a 200 kg ha–1 dose in 2008 and 2009. Due to a small content of nitrogen in Polifoska 6 (6% N), top-dressing nitrogen fertilisation was applied in the form of urea (46% N) at a 100 kg N ha –1 dose. The test plants were winter wheat cultivar Korweta in 2008 and spring rape cultivar Bosman in 2009. The results indicate that the total average manganese, lead and nickel content in soil increased by 15.1%, 5.0% and 3.0%, respectively, under organic fertilisation with and without the active substance compared to the initial content. In the course of time, manganese, nickel and lead content decreased to a different extent. This resulted from these microelements being taken up by the cultivated crop or their leaching outside the rhizo

Lead Pollution and its Assessment of Roadside Soils in Suzhou City

Concentrations of lead in roadside soils from different function areas of Suzhou City were determined and analysed by X-Ray fluorescence spectrometer, and the method of geoaccumulation index. The results indicate that the concentrations of lead in roadside soils range from 23 to 90 mg/kg, with an average value of 37.11 mg/kg, exceeded the environment background value; the lead concentration from high to low is commercial areas, areas around station, industrial areas, urban green space and residential areas; most of roadside soils have not been polluted or only slightly polluted, except sampling site 19, 23 and 49 (moderate pollution).