Potential Groundwater Contamination Research Articles

Suitability Zoning for Sustainable Drainage Systems (SuDSs): Application in a Basin in Southern Brazil

The objective of this study was to propose a set of procedures to assess areas regarding the suitability of sustainable drainage systems (SuDSs) with application in a basin in the urban area of São Carlos (Brazil). The assessment was based on an analysis of 39 attributes reflecting the infiltration conditions that control the functional and constructive aspects of the systems, including subsurface drainability, stability, and groundwater contamination potential, which control the degree of suitability of each plot of land. The data obtained through engineering geological mapping procedures and physical principles were used to characterize the area, which resulted in the division of the basin into five SuDS suitability zones, ranging from favorable to restrictive. The proposed procedures proved to be efficient for analyzing the suitability of different SuDS types and the zoning of an area into terrain units. This approach can help planners identify the most appropriate SuDS types for a given unit, optimize the efficiency/cost relationship, and foresee potential environmental and construction-related challenges. In other words, this procedure enables the assessment of the suitability of SuDSs for different unit terrain types with inexpensive and environmentally efficient technological procedures and resources and can be applied at a fine geographic scale.

Identifying the source of groundwater contaminants in West-Central Wisconsin, U.S.A.: Geochemical and mineralogical characterization of the Cambrian sandstone aquifer

Naturally-sourced groundwater quality issues are common, but there is rarely a geochemical and mineralogical dataset of aquifer properties for comparison. This study utilizes geochemical and mineralogical data to characterize naturally-occurring minerals that are potential groundwater contaminants in the Cambrian Eau Claire – Mount Simon aquitard-aquifer system of west-central Wisconsin, U.S.A. A high-resolution portable x-ray fluorescence elemental analysis was used for initial characterization of geochemistry and chemostratigraphy of well cutting and drill core samples. Then, a subset of sample materials was analyzed mineralogically and geochemically using XRD and ICP-MS, respectively. Elevated concentrations of arsenic, phosphorous, strontium, and various metals within the aquitard-aquifer sandstone were identified, mostly associated with sulfide minerals and iron (hydr)oxides and suggestive of Mississippi Valley-type mineralization. Similar elemental contaminants in surface and groundwater in the study area indicate that the observed trace element-bearing minerals are a natural source of groundwater contamination, most likely through release into groundwater during fluctuating redox and pH conditions near the water table. Co-occurrence of iron (hydr)oxide-coated sulfide minerals near the water table, and observations of sulfide oxidation post-drilling, suggests sulfides in these units are actively oxidizing. Well construction recommendations based on these results should mitigate current or future pumping of trace element-contaminated groundwater and in the vast majority of cases eliminate naturally-occurring contaminants as a potential source. This study provides an extensive baseline dataset of aquifer mineralogy and trace element composition (and an efficient approach for data collection) that is necessary for interpreting and attributing possible future groundwater quality issues.

Geoelectrical and Geochemical Investigations of Selected Dumpsites for Potential Groundwater Contamination in Gusau, Zamfara State, Nigeria

Groundwater contamination has been a worldwide phenomenon. In this research, geoelectric and geochemical surveys were carried out on three active dumpsites in Gusau metropolis for detection of groundwater contamination. Vertical electrical Soundings (VES) were conducted on the dumpsites using Schlumberger array with maximum current electrode separations of 180 m. Five VES were conducted on each dumpsite making a total of fifteen VES along three profiles. Thirty five (35) points were assessed from three wastes dumpsites using portable XRF equipment for the in-situ testing while fifteen (15) representative groundwater samples collected were taken to the laboratory for hydro-geochemical analysis. The field data obtained from VES was analyzed using WinGlink software. The VES results revealed three subsurface layers. The topsoil has resistivity ranging from 1.5Ωm to 48.2 Ωm while the thicknesses vary from 0.47 m to 3.37 m across the profiles. The second layer’s resistivity varies from 5.4 Ωm to 144.35 Ωm and their thicknesses’ ranges from 1.36 m to 16.93 m. The third geoelectric layer has resistivity from 70.0 Ωm to 6003.0 Ωm. The geoelectric results revealed that the top soils in all the dumpsites were characterized by very low resistivity depicting possible pollution and contamination. Environmental pollution models applied to the geochemical dataset revealed Zn, Pb and Cu as moderately contaminants which generally indicated severe potential contamination in the investigated area. While other analytic parameters such as Mn, Cr, Ni and Fe showed low contamination factors. Hydro chemical analysis showed that pH values recorded from the water samples ranged between 7.26 to 8.12 with mean value of 7.50, whereas, recorded Total dissolve solid (TDS) ranged between 377 to 1393mg/L with average concentration of 751.27mg/L. Findings from the study indicated that there may be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are not taken into consideration at the dumpsites.

Identifying potential groundwater contamination by mining influenced water (MIW) using flow measurements in a sub-catchment of the “Cradle of Humankind” Unesco World Heritage Site, South Africa

Identifying potential groundwater contamination by mining influenced water (MIW) using flow measurements in a sub-catchment of the “Cradle of Humankind” Unesco World Heritage Site, South Africa

Integrated geoelectrics and hydrogeochemistry investigation for potential groundwater contamination around a reclaimed dumpsite in Taraa, Ogbomoso, Southwestern Nigeria

Integrated geoelectrics and hydrogeochemistry investigation for potential groundwater contamination around a reclaimed dumpsite in Taraa, Ogbomoso, Southwestern Nigeria

RISK ASSESSMENT OF NEW PESTICIDES TO PUBLIC HEALTH AS POTENTIAL CONTAMINANTS OF UNDERGROUND AND SURFACE WATER SOURCES.

The aim: Risk assessment of amicarbazone, bicyclopyrone and pydiflumetofen to public health as potential contaminants of groundwater and surface water sources in soil and climatic conditions of Ukraine in comparison with other countries. Materials and methods: Hazard assessment to public health was performed according to 3 methods: determination of integrated danger vector (R), integrated groundwater contamination hazard index (IGCHI), risk of adverse effects of studied pesticides to public health (RAEP). Results: The assessment of R and IGCHI indicators showed that the highest level of potential danger to public health due to possible contamination of water sources in Ukraine and other countries (EU, USA, Australia) is inherent in bicyclopyrone. According to the vector R, the potential risk of groundwater contamination with amicarbazone is estimated from medium to high in different soil and climatic conditions; pydiflumetofen - as high; according to IGCHI amicarbazone is recognized as extremely hazardous for humans, while pydiflumetofen can be classified as both hazardous (particularly in Ukraine) and highly hazardous. At the same time, the comparison of potential and permissible exposures showed that the risk of harmful effects on the human body (RAEP) of all 3 substances is acceptable. Conclusions: The risk of contamination of groundwater and surface water with amicarbazone and bicyclopyrone in Ukraine is quite high and coincides with that in other countries; pydiflumetofen in Ukraine shows less migration ability than in some soil and climatic conditions of other countries. Danger assessment of the studied pesticides to public health as potential contamination of water sources in Ukraine and other countries is generally identical.

THE EFFECT OF POULTRY, CATTLE AND SWINE MANURE APPLICATIONS TO SOIL ON LETTUCE YIELD AND QUALITY AND GROUND WATER CONTAMINATION POTENTIAL

This study investigated the effect that poultry, cattle, swine manures, and artificial fertilizer have on the yield and quality of lettuce (Lactucasativa L.). The ground water contamination potential of these fertilizers when applied to calcareous soil was also studied. Lettuce plants were cultivated in pots containing soil amended with either of the fertilizers together with a no-fertilizer control. The amount of fertilizer applied to soil was in line with that used by the lettuce growers in Malta. The experiment, including 20 replicates for each treatment, was set up in a greenhouse and the crop height, width, fresh and dry mass, root length, sap NO3 - and K + , and heavy metal content were monitored. The drain water from the pots was analysed periodically for NO3 - content and salinity. The best crop performance was obtained from poultry manure followed by swine manure, cattle manure and artificial fertilizer. Yield from the control soil was poor and also resulted in a crop containing the highest NO3 - concentration in the sap. No significant difference was found in sap NO3 - concentration in plants grown in soil amended with the fertilizers. The heavy metal content concentration in the plants was not significantly different except for Ni, Mn and Cu. The highest NO3 - leaching was shown in the soil amended with manure, especially with that from poultry. Crops grown on cattle manure showed the highest variation in crop mass and also the lowest yield-to-ground water NO3 - contamination potential ratio.

Sequential injection method for bi-parametric determination of iron and manganese in soil leachates.

The aim of this work was to develop a sequential injection (SI) method for the determination of the micronutrients iron and manganese, in soil leachates, as a tool to assess potential groundwater contamination. The described sequential injection method was based on the reaction of iron with chelator MRB12, a greener alternative chromogenic reagent, and the reaction of manganese with zincon, within a single manifold. The developed SI method enabled the determination of iron in the range 0.10-1.00 mg L-1, and manganese in the range 0.25-2.5 mg L-1 with a limit of detection of 0.08 mg L-1 for iron and 0.24 mg L-1 for manganese. The determination of both parameters was made in 6 minutes, in triplicate. The application to monitor laboratory scale soil core columns (LSSCs), as a simulation of the soil leaching process, proved its efficiency to assess potential contamination of ground waters. Iron and manganese contents were effectively analysed in two different scenarios to mimic the leaching process with rainwater and fertilizer.

Assessing cumulative water impacts from shale oil and gas production: Permian Basin case study

Quantifying impacts of unconventional oil and gas production on water resources and aquatic habitats is critical for developing management approaches for mitigation. The study objective was to evaluate impacts of oil and gas production on groundwater and surface water and assess approaches to reduce these impacts using the Permian Basin as a case study. Water demand for hydraulic fracturing (HF) was compared to water supplies. We also examined contamination from surface spills. Results show that water demand for HF peaked in 2019, representing ~35% of water use in non-mining sectors. Most HF water was sourced from aquifers with ~1,100 wells drilled in the Ogallala aquifer in 2019. The State monitoring network did not show regional groundwater depletion but was not sufficiently dense to address local impacts. Groundwater depletion is more critical in the western Delaware Basin within the Permian Basin because groundwater is connected to large flowing springs (e.g. San Solomon Springs) and to the Pecos River which has total dissolved solids ranging from ~3000 to 14,000 mg/L. Most produced water (70–80%) is disposed in shallow geologic units that could result in overpressuring and potential groundwater contamination from leakage through ~70,000 abandoned oil wells, including orphaned wells. While there is little evidence of leakage from abandoned wells, the state monitoring system was not designed to assess leakage from these wells. Oil spill counts totaled ~11,000 in the Permian (2009–2018). Approaches to mitigating adverse impacts on water management include reuse of PW for HF; however, there is an excess of PW in the Delaware Basin. Treatment and reuse in other sectors outside of oil and gas are also possibilities. Data gaps include reporting of water sources for HF, PW quality data required for assessing treatment and reuse, subsurface disposal capacity for accommodating PW, and spills from PW in Texas.

Characterization and pollution potential of leachate from urban landfills during dry and wet periods in arid regions

Abstract Leachate originating from municipal solid waste landfills poses a serious contamination threat to public health. The study performed a bio-physicochemical characterization of leachate from two landfills in Oman, i.e., Multaqa landfill leachate (MLL) and Barka landfill leachate (BLL) before and after rainfall. Samples were characterized for 92 parameters. Additionally, the leachate pollution index (LPI) was estimated to assess the expected contamination levels and potential environmental health risks. The study found a high value of the leachate parameters without any rainfall incidents. Pearson correlations (±ve) are seen at more than 90% in all cases, which is a strong association (r>0.75) for the measured parameters in both MLL and BLL. Rainfall significantly reduced the concentrations of organic contaminants and solids in leachate due to dilution. The study revealed about 18%–29% and 14%–28% reductions in the LPI sub-index for organic and inorganic contaminants, respectively, after rainfall. The overall LPI values were higher compared with similar findings from the literature. Such deviations could be attributed to the unsegregated nature of solid waste, resulting in the formation of contaminants or from the disposal of a high volume of solid waste in a smaller area. Therefore, the study recommends efficient management strategies for landfills to reduce potential leachate groundwater contamination.

Potential Impacts of Shale Gas Development on Inorganic Groundwater Chemistry: Implications for Environmental Baseline Assessment in Shallow Aquifers

The potential contamination of shallow groundwater with inorganic constituents is a major environmental concern associated with shale gas extraction through hydraulic fracturing. However, the impact of shale gas development on groundwater quality is a highly controversial issue. The only way to reliably assess whether groundwater quality has been impacted by shale gas development is to collect pre-development baseline data against which subsequent changes in groundwater quality can be compared. The objective of this paper is to provide a conceptual and methodological framework for establishing a baseline of inorganic groundwater quality in shale gas areas, which is becoming standard practice as a prerequisite for evaluating shale gas development impacts on shallow aquifers. For this purpose, this paper first reviews the potential sources of inorganic contaminants in shallow groundwater from shale gas areas. Then, it reviews the previous baseline studies of groundwater geochemistry in shale gas areas, showing that a comprehensive baseline assessment includes documenting the natural sources of salinity, potential geogenic contamination, and potential anthropogenic influences from legacy contamination and surface land use activities that are not related to shale gas development. Based on this knowledge, best practices are identified in terms of baseline sampling, selection of inorganic baseline parameters, and definition of threshold levels.

The prevalence and levels of enteric viruses in groundwater of private wells in rural Alberta, Canada

The prevalence and levels of enteric viruses in untreated groundwater of private wells used for drinking and/or agricultural practices in rural Alberta were studied using the qPCR panel assay, integrated cell culture with qPCR and cell culture in the volume of 500 liters per sample through serial sampling. Seven viruses were assessed including adenovirus, rotavirus, norovirus, astrovirus, sapovirus, reovirus and JC virus. Five viruses were detected with an overall positive detection rate of 6.33 % (45 of 711 samples). The most frequently detected virus was adenovirus (48.9%, 22/45) followed by rotavirus (44.4%, 20/45), reovirus (20%, 9/45), JC virus (6.7%, 3/45) and norovirus (6.7%, 3/45). There was no significant difference in the positive detection rates, ranging from 1.1% to 3.4% by various well settings used for broiler farms, cow/calf farms, feedlots and rural acreages. Effects of well characteristics (aquifer type, well depth, static level of water, well seal) and well completion lithology on potential viral contamination of groundwater of private wells were also analyzed upon available data. The findings demonstrate that occurrence of enteric viruses is low and viral contamination is sporadic in groundwater of private wells in rural Alberta. Conventional fecal bacterial indicators (coliform and/or E. coli) were not a representative marker for viral contamination in groundwater wells in rural Alberta.

Hydrogeochemical and health risk investigation of potentially toxic elements in groundwater along River Sutlej floodplain in Punjab, Pakistan.

Understanding groundwater quality and hydrogeochemical behavior is important because consumption of the potentially toxic elements (PTEs)-contaminated drinking water may induce several health problems for humans and animals. In the current study, we examined the potential groundwater contamination with various PTEs (arsenic, As; cadmium, Cd; copper, Cu; manganese; Mn) and the PTEs-induced health risk. Groundwater (n = 111) was characterized for total As, Cd, Cu, and Mn concentrations and other water quality attributes along the River Sutlej floodplain of Punjab, Pakistan. Results revealed that groundwater, which is used for drinkingpurpose, contained high concentrations of As and Cd (mean As: 33µg/L, mean Cd: 3µg/L), exceeding 100% and 32% than the World Health Organization's safe limits (10 and 3µg/L, respectively) in drinking water. The other water quality attributes (i.e., EC, HCO3, Cl and SO4) were also found above their safe limits in most of the wells. Hydrogeochemical data showed that groundwater was dominated with Na-SO4, Na-Cl, Ca/Mg-CO3 type saline water. The hazard quotient and cancer risk indices values calculated for As and Cd indicated potential threat (carcinogenic risk > 0.0001 and non-carcinogenic risk > 1.0) of drinking groundwater in the study area. This study shows that the groundwater along River Sutlej floodplain poses a health threat to the communities relying on it for drinking and irrigation due to high concentrations of As and Cd in water. Moreover, it is important to monitor groundwater quality in the adjacent areas along River Sutlej floodplain and initiate suitable mitigation and remediation programs for the safety of people's health in Punjab, Pakistan.

Simulation of transport and persistence of carbamate aldicarb in soil columns

This study evaluated the mobility and persistence of aldicarb and its degradation products in red-yellow oxisol (LVA) using soil columns, after the application of Temik 150. Leaching experiments were performed using polyvinyl chloride (PVC) columns filled with soil contaminated with aldicarb and rain simulation of 6.05 mm day-1, at 10 day intervals, for 90 days. Aldicarb, aldicarb sulfoxide and aldicarb sulfone residues were extracted from soil (solid-liquid) and percolated water (liquid-liquid) samples with quantification by CG-FID. The results showed that aldicarb was rapidly oxidized to aldicarb sulfoxide and aldicarb sulfone in 10 days after the application. Aldicarb sulfoxide percolated through 15 cm of the soil column and could not be detected in the soil after 40 days incubation. From the 60 days since application, residues were no longer detected in the samples of percolated water and soil fractions, indicating rapid degradation and low potential for groundwater contamination.

Forecasting of Dangerous Influence of Avermectin Insecticides to Human Organism Using Surface and Groundwater for Drinking

More than 400 types of harmful organisms cause damage to agricultural crops. Insecticides occupy one of the last places in the structure of the pesticides assortment among formulations authorized for application in the world. However, they occupy the first place according to their toxicity and the hazard effect to the human body. The purpose of our study was comparative hygienic assessment of soil stability, surface and groundwater migration potential, prediction of dangerous effects of insecticides-avermectins on the human body after using surface and groundwater for drinking needs. For an integral assessment of the potential danger of pesticide exposure to the human body after consumption of water from surface and groundwater supply sources, a scale of four gradations was used. It includes the LEACH (index of potential contamination of groundwater and river waters), half-life period (DT50) in water and an allowable daily dose (ADD) or acceptable daily intake (ADI). It has been established that in different soil and climatic conditions, according to the LEACH index, there is a very low risk of groundwater and surface water contamination. This is due to their relatively high solubility in water, low soil persistence and very high values of the organic carbon sorption coefficient. According to the IIWH index (integral index of water hazard), abamectin and emamectin benzoate in different soil and climatic conditions are moderately hazardous for a person after consumption of contaminated drinking water (class 3); emamectin benzoate in the soil and climatic conditions of Ukraine is hazardous (class 2). It is necessary to monitor carefully the boundaries of sanitary-protective areas from treated areas to water bodies, and control the process of exploitation of water supply sources, especially decentralized in rural areas. In regions with intensive agricultural production, it is recommended to use the IIWH index to make a decision about the necessity of monitoring research on insecticides in water.

Interpreting regolith data to infer groundwater potential contamination in Piracicaba, Brazil

Interdisciplinary concepts have been used to manage the environmental crisis of the 21st century. Ecological problems and solutions require an increasingly comprehensive soil study and this has been carried out in order to consider the entire regolith profile. Regoliths are the entire column of materials above the fresh rock, whether this is saprolite (literally “rotten rock”) or soil, material with intense biological and chemical process. Groundwater contamination is particularly enhanced in shallow, porous regolith profiles, due to the easiness of surface water flow into the groundwaters. This is particularly critical in the Guarani aquifer, which waters supplies 15 million people in 4 countries. Several morphological, chemical, physical and mineralogical analyses were applied to samples collected in three regolith profiles to infer, based on weathering and pedogenesis characteristics, their susceptibility to allow groundwater contamination. A particular challenge was that most of the weathering indices were proposed for igneous rocks, and the studied profiles had sedimentary rocks as parent materials. The most weathered profile (P2) had the least potential for groundwater contamination due to its higher cation exchange capacity (CEC) and clay activity, differentiated structure and consistency in the Bi horizon that can favor the lateral flow and the greatest thickness. Profile P1 had sandy texture, small CEC and thickness that facilitate the passage of soluble contaminants towards the groundwater. Some anox features in the Cr layer suggest the existence of a physical limitation that may delay infiltration or diverge water flow to surface outlets. The profile P3 had the greatest potential for groundwater contamination because it had low CEC, weathering degree and thickness. The only feature to prevent the polluted infiltration water to reach groundwaters in this profile was its sub-horizontal structure and transition from soft/very friable consistency in CA layer to very hard/unbreakable consistency in Cr layer, which also may diverge or delay the vertical infiltration of water. However, no anox features were found in it. Results indicate the importance of understanding the soil weathering and relate with their potential on underground water contamination, and thus, to bring light to public environmental monitoring policies.

Enteric viruses in lentic and lotic freshwater habitats from Brazil's Midwest and South regions in the Guarani Aquifer area.

The present study reports the monitoring of viruses indicating fecal contamination in two distinct regions affected by poor management of wastewater located above the Guarani Aquifer, which is one of the biggest freshwater reservoirs in the world. In the city of Três Lagoas (located in the Midwest region, in the state of Mato Grosso do Sul), water samples were collected from Lagoa Maior, a lake used for recreation, and in Concórdia (located in the South region, in the state of Santa Catarina), from the Queimados River, which crosses the urban area. Four sampling sites were monitored from March to July 2018 in Lagoa Maior, and four sampling sites were monitored along the urban part of the Queimados River area over two periods (rainy and dry). Water samples were analyzed by concentration of Human adenovirus (HAdV), Norovirus (NoV), Rotavirus A (RAV), and Hepatitis A virus (HAV) for the Lagoa Maior samples and RVA, HAV, and Porcine circovirus 2 (PCV2) for the Queimados River samples. All sampling sites presented enteric viruses, demonstrating fecal input and potential contamination of groundwater. Results highlight the need for wastewater management to improve environmental health quality.

Degradation and sorption of the herbicides 2,4-D and quizalofop-P-ethyl and their metabolites in soils from railway tracks

BackgroundBroad spectrum of activity and low potential for leaching to groundwater are important arguments for the application of the herbicide glyphosate on railway tracks. Nevertheless, certain weeds are insufficiently controlled or develop resistance, and there is also an ongoing controversial discussion about possible carcinogenicity of glyphosate. Alternatives are thus strongly desired. 2,4-D and quizalofop-P-ethyl (QE) are two selective herbicides with a complementary spectrum of activity. When used in agriculture, the compounds and their metabolites exhibit low groundwater contamination potential. Uses on railway tracks may, however, be more critical, since degradation likely is slower and mobility higher than in agricultural soils. In this study, we investigated degradation and sorption of the two active substances as well as five metabolites in three soils collected from railway tracks and in a crushed sand, used for construction works.ResultsIn these railway materials, the compounds were indeed degraded slower than in agricultural soils (mean half-lives differed by a factor of 1.4–26, depending on the substance) and mobility was higher (mean sorption coefficients differed by a factor of 3–19). Half-lives and sorption coefficients were also estimated by extrapolation of data from agricultural soils, considering the organic carbon content of railway soils and agricultural soils. Estimated values were more conservative than measured values.ConclusionsBased on our experimental data, possible leaching to groundwater is predicted to be highest for 2,4-D and quizalofop-acid, the primary metabolite of QE, moderate for 2,4-dichlorophenol, the primary metabolite of 2,4-D, but low for QE. Secondary and tertiary metabolites were formed in only low quantities. For herbicides, for which no measured parameters are available for railway soils, estimated values may also be a viable alternative for a first tier groundwater assessment.

Assessment of potential groundwater contamination by ground source heat pump operation using solute transport models

Globally, over the past few decades, there has been a rapid increase in the use of ground source heat pump (GSHP) systems for heating and cooling purposes. Although these systems are more energy efficient than conventional air source heat pump systems, their association with potential groundwater contamination risks, e.g., the leakage of heat exchanger fluids like glycol, is a major concern. In this study, HYDRUS software was used to simulate the transportation of fluids from such systems into an aquifer. To better understand the transport environment, a geological survey was conducted and a > 50 m deep observation well was dug close to the GSHP installation site. To determine the physical properties of the soil, core samples were collected and analyzed; to determine the flow rate of the groundwater as well as the hydrological properties of the aquifer, measurements were conducted using a velocimeter that was installed in the borehole of the observation well. A laboratory column containing aquifer soil was used to determine drainage breakthrough curves. The hydrological parameters of the soil and the solute were used for the simulation under a virtual groundwater environment. The flow of groundwater resulted in the dispersion of the contaminant from its source, and its concentration was significantly reduced owing to degradation presumedly by biological activity. Additionally, two methods for the elimination of the contaminant from aquifers (enforced biodegradation and decontamination by pumping) were identified.

Vertical distribution and affecting factors of Escherichia coli over a 0–400 cm soil profile irrigated with sewage effluents in northern China

Quantification and evaluation of the spatial distribution and the primary factors that affect Escherichia coli (E. coli) distribution in soils is important to assess soil pollution and potential contamination of groundwater. However, little information is available on distribution of E. coli in deep soil layers. To analyze the spatial distribution and factors affecting E. coli over a 0–400 cm soil profile, soil samples were collected from two land use type in the sewage irrigation fields. The primary factors dominating the spatial distribution of E. coli were quantified by the model of principal component analysis with multiple linear regression (PCA-MLR). The results indicated that the number of E. coli under cropland decreased greatly with soil depth. The average number of E. coli over the 0–400 cm profile under forestland was 49 × 104 colony-forming unit/g (cfu/g), which was significantly higher than that under cropland (20 × 104 cfu/g). For forestland and cropland, the average number of E. coli at depths of 300–400 cm decreased by 85% and 88%, respectively, compared to that at depths of 0–100 cm. The presence of E. coli at the depths of 300–400 cm was at high level (forestland: 3 × 104 cfu/g; cropland: 2 × 104 cfu/g) for the potential risks of shallow groundwater. The PCA-MLR model estimated that the factors of soil organism, soil salt and land type use contributed 28%, 29% and 43%, respectively, to the distribution of E. coli. According to the Monte Carlo simulation, the average number of E. coli over the 0–400 cm profile was 46 ± 17 × 104 cfu/g in the sewage irrigated area, and the interval distribution with a probability of 95% varied between 14 × 104 cfu/g and 78 × 104 cfu/g. The findings of this study are useful for understanding negative effects of sewage irrigation on pathogens in deep soil and are critical to assess the potential risks of groundwater pollution.