Environmental fate of pesticides used in Australian viticulture V. Behaviour of atrazine in the soils of the south Australian Riverland

The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile in such strongly alkaline, sandy loam soils and that the irrigated soils of this region are likely to be prone to leaching of atrazine, and therefore that groundwater supplies in this area may be at risk of contamination through use of triazine herbicides.     

Arsenic in garden soils and vegetable crops in Cornwall,England: Implications for human health

Total concentrations of arsenic in surface (0–15cm) garden soils in the historical mining area of Hayle-Camborne-Godolphin, Cornwall, England are large and range widely (144–892 g/g). Amounts of water soluble and acid-fluoride extractable soil arsenic are significantly correlated with total content.Examination of 6 salad and vegetable crops grown in 32 gardens has shown arsenic concentrations in the edible tissues to be only slightly elevated. There were strong correlations between arsenic in beetroot, lettuce, onion and peas and soil arsenic (total, water soluble and acid extractable). Regression equations have been calculated. Ridge regression analysis applied to test the importance of other soil variables has shown both iron and phosphorus to influence the uptake of arsenic.Arsenic in all the vegetables sampled was below the statutory limit in the U.K. of 1 mg/kg fresh weight. Implications for health should be assessed in relation to other exposure routesvia water, air and directly ingested dust and soil.     

Human bioaccessibility of Cr, Cu, Ni, Pb and Zn in urban soils from the city of Torino, Italy

Several physiologically based extraction procedures have been proposed to estimate the fraction of the potentially toxic element content that would be bioaccessible in the human gastro-intestinal tract following accidental ingestion of soil. Many of these procedures are complex, they have been applied to a very limited range of soils, and most work has focussed on arsenic and lead. In the present study, a simplified, two-stage extraction, simulating the human stomach and intestine, was developed and applied to urban soil samples from ten public-access areas in the City of Torino, Italy. The human oral bioaccessibility of chromium, copper, nickel, lead and zinc was estimated. Lead and zinc bioaccessibilities were found to be higher in the stomach, but chromium was more bioaccessible in the intestine. Analyte concentrations were higher in roadside soils than in soils from parks. A higher proportion of the soil metal content was found in bioaccessible forms at roadsides than in parks. Comparison of the current findings with results of earlier work involving sequential extraction of the same soils indicated that the sequential procedure gave a relative, but not an absolute, indication of bioaccessibility. Calculations based on the bioaccessible analyte concentrations suggest that ingestion of only 2–3 g of some of the roadside soil samples from Torino could deliver the tolerable daily oral intake of chromium, nickel and lead to a 20-kg child. The developed procedure is useful for preliminary screening of soils and prediction of whether their bioaccessible metal contents are likely to pose a risk to human health.     

Mobility and adsorption of the triketone herbicide mesotrione in the soil of corn crops

The triketone herbicide mesotrione has been applied pre‐emergence at the dose of 150 g a.i. ha^?1 on corn fields grown within the same period of time at different sites on clay, loam, sandy loam or sandy soils. During the crops and one month after the corn harvest, the mobility of mesotrione has been measured in the 0–20 cm surface soil layer, soil samples being taken in the 0–2,2–4,4–6,6–8, 8–10, 10–15 and 15–20 cm surface soil layers. During the first month after the treatment, mesotrione remained in the 0–2 cm surface soil layer. Thereafter, mesotrione was at a higher concentration in a 2 cm‐thick soil layer which progressively moved down in the clay, loam and sandy loam soils. In the sand soil, mesotrione moved down as a uniform diffusion, its concentration being similar in all the 2 cm‐thick layers of the 0–10 cm soil surface layer. Low mesotrione residues (6–10 ug kg^?1 dry soil) attained the 10–15 cm layer faster in the clay and sand soils than in the loam and sandy loam soils. Mesotrione was not detected in the 15–20 cm soil layer of the loam and sandy loam soils, but well in the sand and clay soils. In the soils of the corn crops mesotrione thus mainly remained in the 0–10 cm surface soil layer. This low mobility and depth of penetration conjugated to the rate of mesotrione soil degradation explain why there was no movement of mesotrione toward the deeper soil layers. The adsorption of mesotrione was greatest on the soils recently treated with organic fertilizers, and having a loam or sandy loam texture. The adsorption coefficients explained the lower mobility and the greatest persistence of mesotrione in these soils.     

黄土性土壤对砷的净化作用及迁移规律研究

通过土柱淋滤试验,从动态角度研究了黄土性土壤对砷的净化作用及迁移规律。研究结果表明,黄土性土壤对砷是一次性的吸附净化并达到饱和状态。土壤对砷净化吸附分为3个阶段:全吸附段、部分吸附段和吸附饱和段。受土壤粘粒和钙影响,黄土性土壤中砷运移的速度不同,其顺序为v(粘化层)相似文献   

珠江三角洲稻田土壤砷及其向水稻籽粒迁移特征

采集珠江三角洲区域水稻(Oryze sativa L.)植株的根系、秸秆、稻谷和对应的耕层土壤(0～15锄)样品,分析土壤和水稻植株中砷含量,初步研究土壤砷与土壤基本理化性质的关系及砷在土壤-水稻系统中的迁移规律.结果表明,土壤砷含量在1.83～18.14 mg·kg~(-1)之间,土壤砷与土壤有机质、砂粒含量呈显著负相关,与土壤粉粒含量呈显著正相关.糙米中的砷含量在0.21～0.43mg·kg~(-1)之间,均未超过国家食品卫生标准(0.7mg·kg~(-1)),砷在水稻植株中的分布规律为根>秸秆>颖壳>糙米.糙米砷含量与秸秆砷含量呈极显著正相关,与秸秆中P/As、Si/As摩尔比呈极显著负相关,因此,降低秸秆中As的积累、增加秸秆中P、Si的积累可降低水稻籽粒中的砷含量.     

Persistence of the sulfonylurea herbicide iodosulfuron-methyl in the soil of winter wheat crops

On four winter wheat fields grown on soils of different textures in Belgium, 10?g a.i.?ha^?1 of the sulfonylurea herbicide iodosulfuron-methyl-sodium was applied post-emergence in the spring. A procedure was developed for the analysis in field soils of iodosulfuron-methyl 1 and of its metabolites iodosulfonamide 2 and iodosaccharin 3 with a sensitivity limit of 0.3?µg of equivalents of iodosulfuron-methyl 1 kg^?1 dry soil. GC and GC-MS was used after purification of the soil extracts by repeated TLC, and methylation. The results of the chemical analyses were confirmed by means of bioassays using sugar beet as test plants. On a winter wheat crop grown on sandy loam soil of pH 6.2 at Melle, iodosulfuron-methyl-sodium 1 was applied at the beginning of April. The iodosulfuron-methyl 1 soil half-life in the 0–10?cm surface soil layer was 60 days. At the end of June, the sum of the concentrations of the metabolites 2 and 3 in the 0–10?cm surface soil layer attained a maximum corresponding to 27% of the applied dose. Green manures were sown after the harvest of the wheat at the end of August. No phytotoxicity at all was observed during the growth of the green manures, in spite of the very low residues of iodosulfuron-methyl 1 remaining in soil in September and October. At the mid of November, iodosulfuron-methyl 1 and its metabolites 2 and 3 were no more detected in soil. On three other winter wheat crops grown on clay soils of pH of about 8 at Leke, Gistel and Zevekote, iodosulfuron-methyl-sodium 1 was applied at the beginning of May. The soil half-life of iodosulfuron-methyl 1 in the 0–10?cm surface soil layer was between 30 and 44 days. Since the application and until the mid of November, in all the trials made on sandy loam or clay soils, iodosulfuron-methyl 1 (and its metabolites 2 and 3 in the trial made on sandy loam soil) were never detected in the 10–15 and 15–20?cm surface soil layers, indicating their low mobilities in the field soils.     

Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

As a new technology used for the cleaning of chromium-contaminated soil, worldwide interest in eletrokinetic (EK) remediation has grown considerably in recent times. However, owing to the fact that chromium exists as both cationic and anionic species in the soil, it is not an efficient method. This paper reports upon a study in which a process using approaching anodes (AAs) was used to enhance the removal efficiency of chromium by eletrokinetics. Two bench-scale experiments to remove chromium from contaminated soil were performed, one using a fixed anode (FA) and the other using AAs. In the AAs experiment, the anode moved toward the cathode by 7 cm every three days. After remediation, soil pH, total chromium, and fractionation of chromium in the soil were determined. The average removal efficiency of total chromium was 11.32% and 18.96% in the FA and AAs experiments, respectively. After remediation, acidic soil conditions throughout the soil were generated through the use of AAs, while 80% of the soil remained neutral or alkalic when using the FA approach. The acidic soil environment and high field intensity in the AAs experiment might have favored chromium desorption, dissolution and dissociation from the soil, plus the mobility of chromium in the soil was also enhanced. The results demonstrate that AAs used in the process of EK remediation can enhance the efficiency of chromium removal from soil.     

Contamination and vertical distribution of As,Cd, Cr,Cu, Pb,Tl, and Zn in paddy soil irrigated with untreated leachate from tailings retention ponds

The contamination and vertical distribution of As, Cd, Cr, Cu, Pb, Tl, and Zn in paddy soil irrigated with untreated leachate from the tailings retention pond were investigated. As, Cr, Cu, and Zn were slightly contaminated in the surface soil and hence their vertical distribution was not obvious. However, Cd and Pb were highly contaminated in the surface soil, while their concentrations decreased with depth, being negatively correlated with pH and positively with total organic matter. Tl was considerably contaminated in the surface soil and a V-shaped vertical distribution was observed where the concentration increased to a maximum at about 30 cm depth and decreased thereafter. The findings revealed that the regular irrigation with untreated leachate from the tailings retention ponds could cause considerable contamination of Cd, Pb, and Tl, and thus tailings should be stringently treated before disposal to minimize their potential environmental impacts on the surroundings.     

Biogeochemical transfer and dynamics of iodine in a soil–plant system

Radioactive iodide (¹²⁵I) is used as a tracer to investigate the fate and transport of iodine in soil under various leaching conditions as well as the dynamic transfer in a soil–plant (Chinese cabbage) system. Results show that both soils (the paddy soil and the sandy soil) exhibit strong retention capability, with the paddy soil being slightly stronger. Most iodine is retained by soils, especially in the top 10 cm, and the highest concentration occurs at the top most section of the soil columns. Leaching with 1–2 pore volume water does not change this pattern of vertical distributions. Early breakthrough and long tailing are two features observed in the leaching experiments. Because of the relatively low peak concentration, the early breakthrough is really not an environmental concern of contamination to groundwater. The long tailing implies that the retained iodine is undergoing slow but steady release and the soils can provide a low but stable level of mobile iodine after a short period. The enrichment factors of ¹²⁵I in different plant tissues are ranked as: root > stem > petiole > leaf, and the ¹²⁵I distribution in the young leaves is obviously higher than that in the old ones. The concentrations of ¹²⁵I in soil and Chinese cabbage can be simulated with a dual-chamber model very well. The biogeochemical behaviors of iodine in the soil-cabbage system show that cultivating iodized cabbage is an environmentally friendly and effective technique to eliminate iodine deficiency disorders (IDD). Planting vegetables such as cabbage on the ¹²⁹I-contaminated soil could be a good remediation technique worthy of consideration.     

Preliminary assessment of surface soil lead concentrations in Melbourne,Australia

Urban soils in many cities have been found to be contaminated with lead from past usage of leaded petrol, deteriorating lead-based exterior paints and industrial sources. Currently, the spatial distribution of soil lead concentrations in the Melbourne metropolitan area is unknown. The objective of this study was to perform a preliminary assessment of the spatial distributions of the surface soil lead (Pb) concentrations in the Melbourne metropolitan area, Australia. Fifty-eight surface soil samples were collected at a depth of 0–2 cm along three linear transects oriented across the Melbourne metropolitan area. Surface soil samples were also collected at a higher density in five Melbourne suburbs. Soil cores (0–50 cm) were collected in four locations, soil transects were collected at intervals with distance away from the roadway (0–50 m) in two inner city parks, and one control soil sample was collected in a rural setting. The median soil Pb concentration of the soil transect samples was 173 mg/kg (range 32–710 mg/kg), and the median soil Pb concentration of the five suburbs was 69 mg/kg (range 9–1750 mg/kg). The suburb of Footscray had the highest soil Pb concentration with a median soil Pb concentration of 192 mg/kg (range 40–1750 mg/kg). Soil Pb concentrations were generally higher nearest the centre of the Melbourne metropolitan area and in the west of Melbourne and lower in the outer suburbs to the east and north of the city centre. Soil Pb concentrations decreased with distance from roadways in the two transects taken from urban parks, and soil lead decreased with depth in the four soil cores. The soil Pb concentrations in the Melbourne metropolitan area appear to be lower than soil lead concentrations observed in inner city areas of Sydney New South Wales (NSW) and Newcastle NSW. The spatial extent of the soil Pb hazard remains undefined in portions of the Melbourne metropolitan area.     

Exposure to Inorganic Arsenic in Soil Increases Urinary Inorganic Arsenic Concentrations of Residents Living in Old Mining Areas

The short term human exposure studies conducted on populations exposed to high concentrations of inorganic arsenic in soil have been inconsistent in demonstrating a relationship between environmental concentrations and exposure measures. In Australia there are many areas with very high arsenic concentrations in residential soil most typically associated with gold mining activities in rural areas. This study aimed to investigate the relationship between environmental arsenic and urinary inorganic arsenic concentrations in a population living in a gold mining area (soil arsenic concentrations between 9 and 9900 mg kg(-1)), and a control population with low arsenic levels in soil (between 1 and 80 mg kg(-1)). Risk factors for increased urinary arsenic concentrations were also explored. There was a weak but significant relationship between soil arsenic concentrations and inorganic urinary arsenic concentration with a Spearman correlation coefficient of 0.39. When participants with greater than 100 mg kg(-1) arsenic in residential soil were selected, the coefficient increased to 0.64. The geometric mean urinary inorganic arsenic concentration for the exposed group was 1.64 microg L(-1) (相似文献   

Dissipation of the triketone mesotrione herbicide in the soil of corn crops grown on different soil types

The new triketone herbicide mesotrione corresponds to the older sulcotrione in which the 2‐chloro benzoyl substituent is replaced by a nitro group, generating an herbicide of greater efficiency and a broader spectrum of activity. Mesotrione has been applied within the same 15 days period pre‐emergence at the rate of 150gha^‐1 to four corn crops made at different sites located 40 km apart in Belgium and of soils of different textures, but similar pH and organic matter (old humus) contents. The mesotrione soil half‐life in the 0–10 cm surface soil layer (which contained more than 90% of the residue) was 50 days in loam soil (at Zarlardinge), 41 days in sandy loam soil (at Melle) and in clay soil (at Koksijde), and 34 days in sandy soil (at Zingem). The cumulative effects of the recent organic fertilizer treatments and of the soil texture could explain the differences between the soil half‐lives. The time for the 90% dissipation of mesotrione was between 3.6 (in the sandy soil) to 4.7 months (in the sandy loam, loam and clay soils). The low mesotrione soil residues remaining after the corn harvest should disappear with the usual heavy rains in autumn, and the tilling which precedes the following crop and dilutes the mesotrione soil residue. These low mesotrione soil residues thus should have no phytotoxicity toward the following crop, especially at the lower application dose of 100 g mesotrione ha^‐1 used in practice.     

Ableitung ökotoxikologisch begründeter Bodenqualitätskriterien am Beispiel Arsen

Background

A vast amount of data on the concentration of substances in soils is being generated in environmental monitoring programmes. This data has to be assessed in terms of effects on terrestrial biota. Benchmarks for such an assessment have been missing up to now. This gap has been filled by the development of a concept for the derivation of ecotoxicologically based soil quality criteria (SQC) and the application of this concept to environmentally relevant substances.

Objectives

The derivation method was applied to arsenic. The derivation process was described in detail from the compilation of data regarding effects on microbial processes, plants, and soil invertebrates to the formulation of a recommendation for an SQC.

Methods

The conceptual framework for the derivation of ecotoxicologically based SQC was developed after reviewing national and international concepts for the assessment of the effects of substances on terrestrial communities. For the assessment of arsenic effects, all relevant biotic processes and trophic levels have been taken into account. Moreover, soil characteristics that may affect the toxicity to biota have been reviewed.

Results

Effects of arsenic on biota may occur at soil background concentrations or slightly above. There are only a few studies in which the influence of soil characteristics, such as soil pH, soil texture, and soil organic carbon, on the effects of arsenic has been investigated systematically. That is why the SQC was oriented on soil background concentrations for sandy soils (5 mg As/kg soil dw). A comparison of the SQC derived in this work with ecotoxicologically based soilquality values from Canada, Denmark, the Netherlands, and the United States shows an average value of 16 mg As/kg, with a range between 5 and 34 mg/kg. The variations in the soil quality values are mainly due to differences in the derivation approaches.

Conclusions and Outlook

The concept applied is considered suitable for the derivation of SQC designed to protect terrestrial communities against direct effects of substances in soils. Therefore, its use is planned to derive SQC for other environmentally relevant substances. In addition to compensation factors, statistical methods should be taken into account to compensate for risks which cannot be quantified. Furthermore, there is the need for an assessment of indirect effects of soil contaminants on birds and mammals.     

Unwanted metals and hydrophobic contaminants in bioreactor effluents are associated with the presence of humic substances

Biological treatment of landfill leachate is challenging due to the presence of complex compounds. Here, we treated an old landfill leachate using a membrane bioreactor under the following conditions: 24 h for hydraulic retention, 65 days of sludge retention and an average organic load rate of 1.71 ± 0.16 g/L/day. We observed a high removal of ammonia, phosphorous and some metals. However, removal of organic carbon was incomplete. Despite a major removal of suspended solids, hydrophobic and volatile hydrophilic compounds, high concentration of fulvic acid and hydrophilic contaminants was found in the effluent. Overally, we demonstrate that the presence of humic substances in the effluent is associated with the detection of arsenic, copper and chromium and di(2-ethylhexyl) phthalate.     

Field studies on 32P movement and P leaching from flooded paddy soils in the region of Taihu Lake, China

Field experiments were done in two sites, Yixing and Changshu, Jiangsu province, China, to study P movement and leaching in flooded paddy soils. P movement in soil was investigated by using the KH2 32PO4 tracker method, and the amount of P leached from the soil layer in different depths was estimated by measuring P concentrations in the soil solution and saturated hydraulic conductivities in field. Determination was done about one month after P application. There was 46% and 42% of total 32P retained in the 0-5cm layer of soil in the Yixing site and in the Changshu site respectively. The 32P retained in the 25-30 cm layer was only about 1-2% of the total 32P added. Furthermore, 8.01% of 32P in the soil of Yixing site and 16.8% of 32P in the soil of Changshu site was lost from the layer 0-30 cm soil. The seasonal amounts of P leached from the top soil layer and from bottom layer are about 4.5-5.8% and 1.6-2.1% of the total P application, respectively. Changes of total P concentrations in soil solutions during rice growth showed that the fertilizer P applied before flooding of the paddy fields suffered a flash leaching loss and a slow leaching loss. We concluded that the fertilizer P could quickly move in the flooded paddy rice field and parts of it can enter into surface water and ground water. Unless the P application is well managed the risk of P loss and consequently environmental pollution exist.     

Distribution of heavy metals in soil and accumulation in plants at an agricultural area of Umudike,Nigeria

This study assessed the distribution of heavy metals in soil and their subsequent accumulation in plants at a site at Umudike, Nigeria, that had been contaminated by agrochemicals. Soil and plant samples were analysed for zinc (Zn), chromium (Cr) and cadmium (Cd). The highest concentrations of Zn (251.50 mg/kg) and Cd (61.33 mg/kg) were obtained at a soil depth of 0–10 cm. The highest concentrations of Zn (16.52 mg/kg), Cd (27.12 mg/kg) and Cr (164.07 mg/kg) were accumulated by Baphia nitida. The levels of Cd, Cr and Zn in soil were 27.97–61.33, 24.97–45.43 and 148.57–251.50 mg/kg, and their concentrations in B. nitida were 16.18–27.13, 97.99–164.07 and 0.10–16.52 mg/kg, respectively. There were significant correlations between Cd and Cr and Cd and Zn in soil, as well as between Cd and Cr in plants. The concentration of Cd in soil reflected a state of pollution relative to Dutch criteria for soil and the FAO/WHO Codex Alimentarius Commission.     

Field Studies on 32P Movement and P Leaching from Flooded Paddy Soils in the Region of Taihu Lake, China

Field experiments were done in two sites, Yixing and Changshu, Jiangsu province, China, to study P movement and leaching in flooded paddy soils. P movement in soil was investigated by using the KH₂ ³²PO₄ tracker method, and the amount of P leached from the soil layer in different depths was estimated by measuring P concentrations in the soil solution and saturated hydraulic conductivities in field. Determination was done about one month after P application. There was 46% and 42% of total ³²P retained in the 0–5cm layer of soil in the Yixing site and in the Changshu site respectively. The ³²P retained in the 25–30 cm layer was only about 1–2% of the total ³²P added. Furthermore, 8.01% of ³²P in the soil of Yixing site and 16.8% of ³²P in the soil of Changshu site was lost from the layer 0–30cm soil. The seasonal amounts of P leached from the top soil layer and from bottom layer are about 4.5–5.8% and 1.6–2.1% of the total P application, respectively. Changes of total P concentrations in soil solutions during rice growth showed that the fertilizer P applied before flooding of the paddy fields suffered a flash leaching loss and a slow leaching loss. We concluded that the fertilizer P could quickly move in the flooded paddy rice field and parts of it can enter into surface water and ground water. Unless the P application is well managed the risk of P loss and consequently environmental pollution exist.     

Environmental impact of nitrogen fertilization in tea eco-system

To quantify the nitrogen losses through runoff and leaching under a tea plantation in hilly soil, a field experiment was conducted from October 2001 to October 2002 at United Planters Association of Southern India (UPASI), Coonoorin Nilgiri district. Runoff water was collected in the collection tub on most rainy days but the leachate was collected in the soil water sampler when the rainfall exceeded 150 mm. Higher nitrogen fertilization levels significantly influenced the NO3-N concentration in both the runoff and leachate and it was likely to cause adverse environmental impact at the delivery end. The NH4-N and NO3-N concentrations in runoff decreased with the days after fertilizer application. NH4-N concentration reduced from 10.27 mg/l on the 9th day to 1.72 mg/l on the 34th day after fertilizer application. NO3-N concentration reduced from 23.5 mg/l on the 9th day to 4.32 mg/l on the 34th day after fertilizer application. Nitrogen loss varied depending on the quantity of rainfall and runoff. The NO3-N concentration in the leachate increased with increase in depth (18.06 mg/l at 22.5 cm depth to 20.98 mg/l at 45 cm depth) whereas NH4-N concentration decreased with increase in depth (6.32 mg/l at 22.5 cm depth to 5.79 mg/l at 45 cm depth.     

Does the metal content in soil around a pregnant woman’s home increase the risk of low birth weight for her infant?

Low birth weight (LBW) is associated with a number of maternal environmental exposures during pregnancy. This study explored the association between soil metal concentrations around the home where the mother lived during pregnancy and the outcome of LBW. We used a retrospective cohort of 9,920 mother–child pairs who were insured by Medicaid during pregnancy and lived in ten residential areas, where we conducted soil sampling. We used a grid that overlaid the residential areas and collected soil samples at the grid intersections. The soil was analyzed for the concentration of eight metals [arsenic (As), barium (Ba), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and mercury (Hg)], and we then used Bayesian Kriging to estimate the concentration at the actual maternal addresses, since we had the GIS coordinates of the homes. We used generalized additive modeling, because the metal concentrations had nonlinear associations with LBW, to develop the best fitting multivariable model for estimating the risk of LBW. The final model showed significant associations for female infants, maternal smoking during pregnancy, non-white mothers, Cu, and As with LBW. The As variable was nonlinear in relation to LBW, and the association between higher concentrations of As with LBW was strong (p = 0.002). We identified a statistically significant association between soil concentrations of arsenic around the home of pregnant women and an increased risk of LBW for her infant.