Pesticides In Shallow Groundwater Research Articles

Evaluation of the Health Risk and Distribution Characteristics of Pesticides in Shallow Groundwater, South Korea

In this work, a method of simultaneously analyzing pesticide concentration and assessing its risks was developed. Assessments were conducted to evaluate the distribution characteristics and risks to human health of pesticides in shallow groundwater in agricultural areas. We developed multi-residue analytical methods using liquid chromatography (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) to analyze 57 pesticides in groundwater. In addition, risk assessments were performed by setting scenarios considering the routes of pesticide infiltration into groundwater. For the simultaneous analysis of 57 pesticides, the liquid–liquid extraction method was applied twice using dichloromethane under acidic and alkaline conditions. The extract was concentrated and analyzed using LC-MS/MS (41 pesticides) and GC-MS/MS (16 pesticides). The precision and accuracy ranges of the analytical methods were 0.1~12.9% (within ±15%) and 80.3~113.6% (within ±20%), respectively. The limit of quantification was found to range from 0.0004 to 0.0677 μg/L. In total, 57 pesticides were monitored in 200 groundwater wells from 2019 to 2020. Twenty-six pesticides, including metolachlor and imidacloprid, were detected, with an average concentration of 0.0008 μg/L in groundwater. The pesticide types and detection levels differed depending on the survey period and surrounding land. When the risks associated with alachlor, metolachlor, and carbofuran were assessed, their health risks when found in groundwater were evaluated to be negligible (non-carcinogenic risk: less than 10−3, carcinogenic risk: less than 10−6).

Preliminary Evaluation of the Possible Occurrence of Pesticides in Groundwater Contaminated with Nitrates—A Case Study from Southern Poland

This paper addresses groundwater pollution and the potential presence of pesticides within the catchment areas of two reservoirs that are sources of drinking water. The two reservoirs are Goczałkowice and Kozłowa Góra, both in Southern Poland. Agricultural and rural areas dominate both catchments. Archival data showed local groundwater contamination with nitrates. This indicated the possible presence of pesticides in shallow groundwater. In total, 13 groundwater samples from shallow sandy aquifers were collected. All the samples were tested for the presence of 35 organophosphate pesticides and 28 organochlorine pesticides. Additionally, in order to determine the current groundwater conditions, physicochemical parameters were measured in the field, and water samples were subjected to analysis of their chemical composition (incl. the determination of nitrates). The research outcomes showed that pesticides were not detected above the detection limits in any of the samples. Due to variations in the persistence and degradation rates of pesticides, the occurrence of these substances in the groundwater environment and the possibility of their migration to aquifers should not be completely excluded. Natural processes and factors (e.g., sorption, biodegradation, hydrolysis and redox conditions) may gradually reduce the pesticide concentrations in groundwater. The chemical analyses revealed high concentrations of nitrates in the groundwater. This suggests the possible influence of agriculture and fertilizer application on groundwater quality; however, a proportion of NO3- ions may be connected with improper sewage management within the two catchments. The absence of pesticides in groundwater impacted by agriculture may result from processes occurring in the aquifer and the rapid degradation of these compounds due to photolysis and prevailing weather conditions. In the vicinity of dwellings, nitrates also originate from domestic wastewater. Thus, the occurrence of pesticides in groundwater contaminated with NO3 cannot always be expected.

Interaction and coexistence characteristics of dissolved organic matter with toxic metals and pesticides in shallow groundwater

The long-term and large-scale utilization of fertilizers and pesticides in facility agriculture leads to groundwater pollution. However, the coexistence and interactions between organic fertilizers (i.e., organic matter), toxic metals, and pesticides in shallow groundwater have seldom been studied. Thus, the study sought to characterize said interactions via fluorescence, ultraviolet–visible spectroscopy (UV–Vis), and Fourier-transform infrared spectroscopy coupled with two-dimensional correlation spectroscopy and chemometric techniques. The results indicated that groundwater DOM was comprised of protein-, polysaccharide-, and lignin-like substances derived from organic fertilizers. Protein-like substances accounted for the binding of Co, Ni, and Fe, while polysaccharide- and lignin-like substances were mainly responsible for Cr and Mo complexation. Moreover, lignin- and polysaccharide-like substances played a key role in the binding of pesticides (i.e., dichlorodiphenyltrichloroethane [DDT], endosulfan, γ-hexachlorocyclohexane [γ-HCH], monocrotophos, chlorpyrifos, and chlorfenvinphos), rendering the conversion of γ-HCH to β-hexachlorocyclohexane (β-HCH) and the degradation of DDT to dichlorobenzene dichloroethylene (DDE) ineffective. However, the presence of protein-like substances in groundwater benefited the degradation and conversion of γ-HCH and α-endosulfan. Redundancy analyses showed that lignin- and polysaccharide-like matter had the most impacts on the coexistence of DOM with toxic metals and pesticides.

Characteristics and Potential Health Hazards of Organochlorine Pesticides in Shallow Groundwater of Two Cities in the Yangtze River Delta

A total of 52 shallow groundwater samples were collected from two cities, Shengzhou and Shangyu, in the Yangtze River Delta, to characterize the residues of hexachlorocyclohexane (HCH) isomers and dichlorodiphenyltrichloroethane (DDT) isomers/metabolites present and estimate health risk of drinking groundwater. HCH and DDT residues occurred in the shallow groundwater of most of Shengzhou and partial area of Shangyu. Concentrations of total HCH (ΣHCHs) and total DDT (ΣDDTs) in the shallow groundwater ranged from below the detection limit (BDL) to 123.2 ng L−1 and BDL to 321.4 ng L−1 for Shengzhou and BDL to 46.40 ng L−1and BDL to 77.92 ng L−1 for Shangyu. The predominant HCH and DDT species in the shallow groundwater of Shengzhou were δ‐HCH and o,p′‐DDT, and the equivalent species in Shangyu were δ‐HCH and p,p′‐DDT. The low α‐HCH/γ‐HCH ratio, low (dichlorodiphenylethylene (DDE) + dichlorodiphenyldichloroethane)/ΣDDTs ratio and o,p′‐DDE being the dominant DDT metabolite for the majority of samples collected from Shengzhou suggest that there are fresh inputs of lindane and dicofol mixtures in majority area of Shengzhou. The high ratios of p,p′‐DDT/ΣDDTs in half of the groundwater samples collected from Shangyu suggest that there are fresh inputs of DDT in partial area of Shangyu. α‐HCH, β‐HCH, and γ‐HCH in the shallow groundwater in majority area of Shengzhou are posing serious cancer risks to children (>10−6), and the three HCH isomers in the shallow groundwater of Shengzhou should be controlled urgently and effectively.

Concentrations and potential health hazards of organochlorine pesticides in shallow groundwater of Taihu Lake region, China

A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p′-dichlorodiphenyldichlorothane (p, p′-DDD) and p, p′-dichlorodiphenyltrichloroethane (p, p′-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p′-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10−6, posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water.

Pesticides in Shallow Groundwater: Exposure Estimates and Prediction of Cancer risk

Pesticides in Shallow Groundwater: Exposure Estimates and Prediction of Cancer risk

Pesticides in shallow groundwater of Bahawalnagar, Muzafargarh, D.G. Khan and Rajan Pur districts of Punjab, Pakistan

In Pakistan there is little data on environmental contamination of rural water sources by pesticides. This study evaluated pesticide contamination of groundwater in four intensive cotton growing districts. Water samples were collected from 37 rural open wells in the areas of Bahwalnagar, Muzafargarh, D.G. Khan and Rajan Pur districts of Punjab and analysed for eight pesticides which are mostly used. Information on types of pesticide used and distance to nearest pesticide mixing area and application areas was obtained for each site. From the eight pesticides analysed, six pesticides were detected in the water samples. Only cypermethrin and cabosulfan were not detected. The percentage of detection of bifenthrin, λ-cyhalothrin, carbofuran, endosulfan, methyl parathion and monocrotophos was, respectively 13.5%, 5.4%, 59.4%, 8%, 5.4% and 35.1% in July; 16.2%, 13.55%, 43.2%, 8%, N.D. (not detected) and 24.3% in October. Maximum contamination levels (MCLs) established by the U.S. Environmental Protection Agency for drinking water were not exceeded. The study has shown the need for monitoring pesticide contamination in rural water resources, and the development of drinking water quality standards for specific pesticides in Pakistan. The conclusions and recommendations will be disseminated to senior decision makers in central and local governments, extension agents and farmers.

Occurrence of Pesticides in Shallow Groundwater of the United States: Initial Results from the National Water-Quality Assessment Program

The first phase of intensive data collection for the National Water-Quality Assessment (NAWQA) was completed during 1993−1995 in 20 major hydrologic basins of the United States. Groundwater land-use studies, designed to sample recently recharged groundwater (generally within 10 years) beneath specific land-use and hydrogeologic settings, are a major component of the groundwater quality as sessment for NAWQA. Pesticide results from the 41 land-use studies conducted during 1993−1995 indicate that pesticides were commonly detected in shallow groundwater, having been found at 54.4% of the 1034 sites sampled in agricultural and urban settings across the United States. Pesticide concentrations were generally low, with over 95% of the detections at concentrations less than 1 μg/L. Of the 46 pesticide compounds examined, 39 were detected. The compounds detected most frequently were atrazine (38.2%), deethylatrazine (34.2%), simazine (18.0%), metolachlor (14.6%), and prometon (13.9%). Statistically significant rel...

Pesticides and Nutrients In Southern U. S. Shallow Ground Water and Surface Runoff

Nutrient and pesticide concentrations in shallow groundwater (3m) and surface runoff were determined for conventional-till (CT) and no-till (NT) soybean watersheds. Groundwater NO3N concentrations were similar for both tillage systems, averaging about 7-8 ppm, but exceeded 10 ppm for some storms. Annual mean groundwater NO3N concentrations were only 0.34 ppm in a riparian zone downslope from the CT watershed. Higher nutrient concentrations in NT surface runoff reflected surface residue leaching. Runoff from both watersheds, 2 days after a broadcast application of 0-20-20, had high nutrient concentrations that decreased during subsequent storms. Pesticide concentrations in groundwater of the NT watershed were as high as 250 ppb at a depth of 1.5 m within 1 week after application (1st rainfall). Concentrations beneath the CT watershed were < 10 ppb maximum. One month after application, pesticide concentrations in groundwater beneath both watersheds had decreased to about 10% of their respective 1-week values. Similar total pesticide losses in runoff occurred for both tillage systems. NT reduced sediment loss but increased pesticide movement into the soil profile. Results of companion studies with corn at another site indicated similar trends for nutrients and pesticides in shallow groundwater. Within 11 months after application, herbicides were still detectable at very low concentrations (<1 ppb). Soil insecticides, applied at planting, were not found in groundwater. Herbicides and insecticides were detectable in both the water and sediment phases of runoff for 5 months after application. At the 1.5-m depth, the mean NO3N concentration in groundwater for conventional-, reduced-and no-till corn was 4.78 ppm compared with 6.96 ppm at the 3-m depth.

Pesticides in Shallow Groundwater in the Delmarva Peninsula

AbstractA regional study of the areal and depth distribution of pesticides in shallow groundwater in the Delmarva Peninsula of Delaware, Maryland, and Virginia was done to (i) relate the pesticides detected to landscape and shallow subsurface features, and (ii) evaluate aquifer vulnerability and the potential contamination of drinking‐water supplies. Water samples collected at 100 wells from 1988 to 1990 were analyzed for concentrations of 36 pesticides, four metabolites, and other constituents. The most commonly detected residues were atrazine, cyanazine, simazine, alachlor, metolachlor, and dicamba. Concentrations were low; few exceeded 3 µg L−1. Most detections correlate with the intensive use of these herbicides in three widely distributed and commonly rotated crops—corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and small grain—particularly if grown in well‐drained soils. Most detections occurred in samples collected from shallow wells screened within 10 m of the overlying water table. The shallow depth distribution of most residues is consistent with their suspected history of use (ca. 20 yr), and patterns in shallow groundwater flow in the surficial aquifer in the study area. The areal and depth distributions of detectable residues in groundwater did not correlate with a vulnerability index, nor any of the component scores developed to estimate that index using the DRASTIC method. The shallow depth of most detections also indicates why few samples from water‐supply wells in this study had measurable concentrations of pesticides; most supply wells are deeper than 10 m below the water table. The low number of contaminated samples from supply wells implies that deep groundwater currently (1992) used for drinking generally does not contain detectable pesticide residues.