Pesticide Residues In Groundwater Research Articles

DYNAMIC OF HERBICIDES IN SOIL AND SOIL MODIFIED WITH CLAY AND /OR HUMUS

Herbicides are one of the most widely used agrochemical classes around the world. They help farmers to protect their crops against weeds. However, they can move through the soil profile polluting water resources and adversely affect human health. Groundwater is an important source for the production of drinking water in many places of the world and the presence of pesticide residues in groundwater is a serious threat to the health of consumers of drinking water. In this work, the behavior of two herbicides Atrazine and Trifluralin were study in an agricultural soil: Alhue soil and this soil modified whit clay (Kaolinite) and organic matter (Humus). The original soil and modified soil samples were characterized by their physicochemical properties: pH, EC, OC and texture. The analytical method was optimized for the quantification of Atrazine and Trifluralin by High Performance Liquid Chromatography (HPLC). The contact time, adsorption/desorption isotherms, persistence of both compounds in the soil samples and modified soil samples with clay and/or organic matter was studied. In general, all sorption curves for Trizine and Trifuralin in the modified soil samples were similar with relatively low adsorption for Trifuralin indicating that the soil modifications were not significant. The kinetic of sorption process was described by Elovich model. Both herbicides present a low Koc value, however, they present different types of adsorption, being for Atrazine a moderate adsorption and for Trifluralin a weak adsorption, which implies that both herbicides could be distributed in bodies of water as they are not fixed by organic matter. However, it should be noted that Atrazine presents higher Koc values ​​than Trifluralin in all soil samples, which could mean that Atrazine would be less bioavailable than Trifluralin. Values ​​obtained in the Pearson correlation of CO (%) and % of clay are expected since, when observing the results obtained in the Kd parameters for soils modified by both herbicides, they show that the higher the % of the physicochemical parameter, the higher the adsorption of the compound by the soil. The persistence of the pesticides showed that with both the addition of Kaolinite and Humus to the soil increases the half-life time for both herbicides. The results of the GUS index showed that both Atrazine and Trifluralin would be classified as leachable compounds in all soil samples.

Occurrence of Banned and Currently Used Herbicides, in Groundwater of Northern Greece: A Human Health Risk Assessment Approach.

The presence of pesticide residues in groundwater, many years after their phase out in European Union verifies that the persistence in aquifer is much higher than in other environmental compartments. Currently used and banned pesticides were monitored in Northern Greece aquifers and a human health risk assessment was conducted. The target compounds were the herbicides metolachlor (MET), terbuthylazine (TER), atrazine (ATR) and its metabolites deisopropylatrazine (DIA), deethylatrazine (DEA) and hydroxyatrazine (HA). Eleven sampling sites were selected to have representatives of different types of wells. Pesticides were extracted by solid-phase extraction and analyzed by liquid chromatography. MET was detected in 100% of water samples followed by ATR (96.4%), DEA and HA (88.6%), DIA (78.2%) and TER (67.5%). ATR, DIA, DEA, HA, MET and TER mean concentrations detected were 0.18, 0.29, 0.14, 0.09, 0.16 and 0.15 μg/L, respectively. Obtained results were compared with historical data from previous monitoring studies and temporal trends were assessed. Preferential flow was the major factor facilitating pesticide leaching within the month of herbicide application. Moreover, apparent age of groundwater and the reduced pesticide dissipation rates on aquifers resulted of long-term detection of legacy pesticides. Although atrazine had been banned more than 18 years ago, it was detected frequently and their concentrations in some cases were over the maximum permissible limit. Furthermore, human health risk assessment of pesticides was calculated for two different age groups though drinking water consumption. In all examined wells, the sum of the HQ values were lower than the unity. As a result, the analyzed drinking water wells are considered safe according to the acute risk assessment process. However, the presence of atrazine residues causes concerns related with chronic toxicity, since ATR R values were greater than the parametric one of 1 × 10−6 advised by USEPA, for both age groups.

Assessment of pesticide residues in waters and soils of a vineyard region and its temporal evolution

Sustainable agriculture practices and integrated pest management for avoiding environmental pollution are necessary to maintain a high yield in vineyard areas. Pesticide residues in groundwater in a vineyard area of La Rioja (Spain) have been evaluated in previous years, and they could now have varied after farmers have adopted the different measures recommended. Accordingly, this research's objectives were (i) to evaluate the occurrence and seasonal distribution (spring, summer, and autumn samplings) of pesticides (36) plus their degradation products (DP) (11) in water and soil samples (23 + 15) in La Rioja (Northern Spain), and (ii) to compare the current water quality (2019) with that determined previously (2011). A multi-residue method based on solid phase extraction (for water samples) or solid liquid extraction (for soil samples) and high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS) was used to determine and quantify pesticides. The results reveal the presence in waters of 30 compounds from those selected (15 fungicides + 2 DP, 7 insecticides + 1 DP, and 3 herbicides +2 DP), with 14 of them at concentrations > 0.1 μg L−1 (water quality threshold for human consumption). The highest number of compounds was detected in summer (waters) and spring (soils). The pesticides most frequently detected in water samples were the fungicides metalaxyl, tebuconazole, and boscalid, with the last one being the compound found in the highest number of soil samples. The comparison of water pollution in 2011 and 2019 indicates a significant decrease in the total concentration of herbicides, fungicides and insecticides in 95–100%, 76–90%, and 42–85% of samples in the three campaigns, respectively. The results indicate that an optimized and sustainable use of pesticides in intensive and high-yield agricultural areas could reduce environmental pollution.

The migration of pesticide residues in groundwater at a bank filtration site (Krajkowo well field, Poland)

River bank filtration systems are widely used for water supply purposes. Using these systems, the movement of water over short distances between the river bottom and extraction wells can decrease the concentrations of some contaminants. Such systems are especially important for the removal of specific micro-pollutants that seasonally appear in river water. In this article, pesticides migration at the Krajkowo well field is analysed based on different water extraction schemes. The water is extracted by two groups of wells (one located 60–80 m from the Warta River, and the second located more than 400 m from the river) and by a horizontal well with radial drains located 5 m below the river bottom. Based on this scheme, the rate of pesticide residues removal was analysed in wells located at different distances from the river channel. The results of the three sampling campaigns conducted in summer and autumn 2017 and winter 2018 indicate the presence of pesticide compounds in the Warta River (max. total concentration of 0.171 μg/l). The pesticides were also present in the horizontal well (max. total concentration of 0.137 μg/l). Much smaller concentrations (max. 0.064 μg/l) were observed in vertical wells located 60–80 m from the river. Additionally, in the well located 250 m from the river, only two pesticide constituents were detected (at concentrations just above the detection limit), and in a well located 680 m from the river, the concentrations of pesticide residues were below the detection limit (excluding isoproturon, which was slightly above the detection limit). This research illustrates the effectiveness of pesticides removal by river bank filtration.

Dissipation and Adsorption of 2,4-D, Atrazine, Diazinon, and Glyphosate in an Agricultural Soil from Yucatan State, Mexico

Pesticides are used worldwide in farming activities to guarantee crop yields. In southeastern Mexico, groundwater is the primary source of water for humankind. However, because of the soil characteristics and of intensive agricultural practices, the aquifer is vulnerable to pollution as shown by the regular detection of pesticide residues in groundwater. Within this context, the dissipation and adsorption of four of most used pesticides (2,4-D, atrazine, diazinon, and glyphosate) by farmers in southeastern Mexico were studied to determine their fate in agricultural soil and estimate their risk for the aquifer. Forty-one days after their application, the four pesticides were entirely dissipated from the soil. 2,4-D and glyphosate were the most persistent according to DT50. Diazinon was the most adsorbed to the soil at equilibrium time. All pesticides were volatilized in substantial amounts, reaching 10.1, 22.3, 22.4, and 43.4% of initial amount 72 h after application of glyphosate, atrazine, 2,4-D, and diazinon, respectively. Volatilization was dependent on time and pesticide type (P < 0.05). Following their KOC, diazinon and glyphosate were found to be the most prone to leach. Therefore, in the absence of mitigation measures, their use represents a significant threat for the groundwater in Southeastern Mexico.

A health-based regulatory chain framework to evaluate international pesticide groundwater regulations integrating soil and drinking water standards

Pesticide residues in groundwater, mainly transported from contaminated soil, may threaten drinking water sources and cause adverse health effects. Therefore, pesticide groundwater standards were implemented by international environmental agencies to ensure the quality of groundwater, which serves as the direct drinking water source in many countries. However, regulatory inconsistencies are always found among groundwater, soil, drinking water, and even health standards due to the lack of communication among the regulatory processes. This study first developed a health-based regulatory chain framework to analyze pesticide groundwater regulations integrating soil, drinking water, and health regulations. Six regulatory indexes associated with probabilistic risk assessments and pesticide transport modeling were constructed to evaluate the performance of pesticide groundwater regulations identified from 56 countries. Worldwide pesticide groundwater regulations were analyzed by quantifying the impact on the downstream (exposure pathways in general) pesticide drinking water standards and human health and the influence from upstream (environmental pathways in general) soil regulations. The results indicated that in general, worldwide pesticide soil regulations do not encompass a sufficient number of pesticides or provide appropriate standard values to be compatible with groundwater regulations. The computed indexes between pesticide groundwater and drinking water regulations indicated more positive results than soil regulations because most European nations have groundwater regulations that are compatible with those of drinking water. However, most pesticide groundwater regulations could not protect human health according to the health-based indexes. Hopefully, the regulatory framework developed in this study will help environmental agencies comprehensively evaluate and establish pesticide groundwater regulations.

Spatial distribution of pesticide residues in the groundwater of a condensed agricultural area

Pesticide residues in groundwater have caused health and environmental concerns in regions in which the water is used for drinking and irrigation purposes. In this study, seven pesticide residues were studied in groundwater of a condensed agricultural area in the Al-Qassim region, Kingdom of Saudi Arabia using multiresidue gas chromatography coupled with mass spectrometry. Diazinon followed by chlorpyrifos and carbofuran was the most frequently detected pesticide in the collected water samples. In most locations, pesticide residues detected in groundwater samples were above the maximum acceptable levels of total and individual pesticide contamination of 0.5 and 0.1 μg L−1, respectively. The spatial distribution of the detected pesticides showed extremely high concentrations in intensified agricultural areas 55 km southwest of Buraydah. The results of the present study are expected to provide adequate information to enable the formulation of guidelines for permissible pesticide residues in water. Additionally, a regular monitoring program for pesticide residues in water is suggested based on the strict guidelines for pesticidal use.

Fluorescent cadmium sulfide nanoparticles for selective and sensitive detection of toxic pesticides in aqueous medium

The detection of pesticide residues in ground water, food, or soil samples is extremely important. The currently available laboratory techniques have several drawbacks and needs to be replaced. Fluorescent chemosensors for pesticide detection were reported in the literature, with few reports published on quantum dot-based pesticide sensors, but none of these were focused toward differentiating organophosphorus and organochlorine pesticides specifically. In this respect, glutathione-coated CdS nanoparticles were synthesized and characterized. The TEM studies of the nanoparticles suggested mostly monodispersed spherical particles, with size in the range of 11.5±1 nm. The prepared fluorescent nanoparticles were found to selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles ~ 2.5 times. Similar studies carried out with organophosphorous pesticide dimethoate did not result any change in the fluorescence intensity of the nanoparticles. Further studies carried out with commercially available pesticide solutions, also confirmed similar results. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol. Control experiments suggested possible role of both amine and carboxylic acid functional groups of glutathione in the recognition of dicofol. The limit of detection of dicofol was found to be ~ 55±11 ppb. Glutathione-coated CdS nanoparticles selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol.

Occurrence of organochlorine pesticide residues in groundwater and soil from Syrian coastal area

Soil and water samples collected biweekly over 2 month period, starting from 15 May to 30 June 2005 from Syrian costal area were analyzed to determine the occurrence of Pesticides residues and mainly the organochlorine pesticides. None of the conventional pesticides were detected neither in soil nor in water samples, the only insecticides were detected in the samples were the organoclorine insecticides. In water samples, the DDT and it is breakdown products of DDE was detected only in some sampling interval in both coastal governorates Tartous, and Latakia, and concentration typically ranged from 0.0018 to 0.0085 mg/L whereas, the 4,4DDD were almost found in all water samples and ranged from 0.0076 to 0.0705 mg/L. Lindane, and δ BHC were detected in all samples of both governorates at concentration ranged from 0.0202 to 0.0537 and from 0.0106 to 0.136 mg/L respectively. In soil the results showed that, the high level of Lindan residues in all analyzed samples in both governorates. Concentration typically ranged from 8.54 to 22.50 mg/kg, and that was due to the more recent banning of Lindan (in 2000). The residue levels of DDE were the highest among the rest of the detected OC residues and it ranged from 8.54 to 22.50. However the range of residues concentration of the other detected OC. Pesticides were as follow; 4,4DDD from 3.81 to 14.37, 4,4DDT from 2,22 to 12.38, 2,4DDT from 2.94 to 5.28, HCH from 3.18 to 571, 2,4DDD from 0.87 to 4.28 and the combination of Endosulfan and Endosulfan sulfate ranged from 0.05 to 9.18 mg/kg.

Ocorrência de agrotóxicos em águas subterrâneas de áreas adjacentes a lavouras de arroz irrigado

The objective this study was to monitor pesticide residues in groundwater at three different times and in seven regions producing rice in southern Brazil, in the 2007/08 season. Imazethapyr and fipronil were found in all regions studied. All groundwater samples from the Planicie Costeira Interna to Lagoa dos Patos and Santa Catarina contained at least one pesticide. The lowest number of contaminated samples were detected in the Southern region. The highest frequency of contaminated samples was found after drainage of the rice fields. Only fipronil exceeded limits of potability, in 27% of samples, according European Community criteria.

Pesticide residues and transformation products in groundwater from a Spanish agricultural region on the Mediterranean Coast

An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TPs.

Organochlorine pesticide residues in ground water of Thiruvallur district, India

Modern agriculture practices reveal an increase in use of pesticides and fertilizers to meet the food demand of increasing population which results in contamination of the environment. In India crop production increased to 100% but the cropping area has increased marginally by 20%. Pesticides have played a major role in achieving the maximum crop production, but maximum usage and accumulation of pesticide residues was highly detrimental to aquatic and other ecosystem. The present study was chosen to know the level of organochlorines contamination in ground water of Thiruvallur district, Tamil Nadu, India. The samples were highly contaminated with DDT, HCH, endosulfan and their derivatives. Among the HCH derivatives, Gamma HCH residues was found maximum of 9.8 microg/l in Arumbakkam open wells. Concentrations of pp-DDT and op-DDT were 14.3 microg/l and 0.8 microg/l. The maximum residue (15.9 microg/l) of endosulfan sulfate was recorded in Kandigai village bore well. The study showed that the ground water samples were highly contaminated with organochlorine residues.

Organochlorine and organophosphorous pesticide residues in ground water and surface waters of Kanpur, Uttar Pradesh, India

A survey undertaken in Kanpur, northern India, has shown the presence of high concentrations of both organochlorine and organophosphorous pesticides in the surface and ground water samples. Liquid–liquid extraction followed by GC-ECD was used for the determination of these compounds. Among the various pesticides analyzed, high concentrations of γ-HCH (0.259 μg/l) and malathion (2.618 μg/l) were detected in the surface water samples collected from the River Ganges in Kanpur. In the ground water samples collected from the various hand pumps located in agricultural and industrial areas, apart from γ-HCH and malathion, dieldrin was also detected. The maximum concentration values of γ-HCH, malathion and dieldrin were 0.900, 29.835 and 16.227 μg/l, respectively. Especially, the concentration of malathion was found to be much higher than the EC water quality standards in the ground water samples from industrial area posing a high risk to the common people. Pesticides like DDE, DDT, aldrin, ethion, methyl parathion and endosulfan were not detected in both the surface and ground water samples.

Evaluation of Pesticide Contamination of Ground Water in Two Agricultural Areas of Portugal

In two Portuguese agricultural areas, "Beira Litoral" and "Ribatejo e Oeste", several pesticides regularly applied in vineyards, maize, potato, tomato for industry, apple, pear and rice were detected in ground water. Atrazine was the most frequently detected, being found in 70% of the total of 79 sites selected in the year 2000, followed by its metabolites desethylatrazine and desisopropylatrazine with frequencies of detection, respectively, of 56% and 48% and by simazine (37%), alachlor (25%), metolachlor (24%) and metribuzin (15%). Other pesticides and metabolites i.e. 3,4-dichloroaniline, dimethoate, f and g -endosulfan, lindane, molinate and prometryn were also detected but at lower occurrences. Pesticides were detected mainly in ground water wells used for irrigation purposes, although in some locations they were also found in water wells used for human consumption. In this study, it was also observed a seasonal variation of pesticide residues in ground water of shallow and deep wells.

Occurrence and spatial and temporal distribution of pesticide residues in groundwater of major corn-growing areas of Greece (1996-1997).

During 1996-1997, residues of selected pesticides were monitored, at 3-month intervals, in 80 wells, including both irrigation and drinking water wells, distributed among the main corn-growing areas (Pieria, Thessaloniki, Serres, Kavala, and Evros) of Greece. Pesticide residues were found in 48% of the wells; however, in most cases residues were very low ranging from LOQs (quantification limits of the analytical methods) to <0.1 microg/L, while in 11% (nine wells) pesticide residues higher than 0.1 microg/L were present. Most of the latter wells were found in Evros and specificallythe Ardas Valley. The frequency of occurrence, in descending order, was atrazine > DEA > alachlor = metolachlor; however, the order of descending concentrations was atrazine > metolachlor > DEA > alachlor. The occurrence and the spatial and temporal distribution patterns of pesticide residues indicate that at the present the situation of groundwater quality is favorable throughout the corn-growing areas of Greece with the exception of the Ardas Valley.

Pesticide residues in ground water of the San Joaquin Valley, California

A regional assessment of non-point-source contamination of pesticide residues in ground water was made of the San Joaquin Valley, an intensively farmed and irrigated structural trough in central California. About 10% of the total pesticide use in the USA is in the San Joaquin Valley. Pesticides detected include atrazine, bromacil, 2.4-DP, diazinon, dibromochloropropane, 1,2-dibromoethane, dicamba, 1,2-dichloropropane, diuron, prometon, prometryn, propazine and simazine. All are soil applied except diazinon. Pesticide leaching is dependent on use patterns, soil texture, total organic carbon in soil, pesticide half-life and depth to water table. Leaching is enhanced by flood-irrigation methods except where the pesticide is foliar applied such as diazinon. Soils in the western San Joaquin Valley are fine grained and are derived primarily from marine shales of the Coast Ranges. Although shallow ground water is present, the fewest number of pesticides were detected in this region. The fine-grained soil inhibits pesticide leaching because of either low vertical permeability or high surface area; both enhance adsorption on to solid phases. Soils of the valley floor tend to be fine grained and have low vertical permeability. Soils in the eastern part of the valley are coarse grained with low total organic carbon and are derived from Sierra Nevada granites. Most pesticide leaching is in these alluvial soils, particularly in areas where depth to ground water is less than 30m. The areas currently most susceptible to pesticide leaching are eastern Fresno and Tulare Counties. Tritium in water molecules is an indicator of aquifer recharge with water of recent origin. Pesticide residues transported as dissolved species were not detected in non-tritiated water. Although pesticides were not detected in all samples containing high tritium, these samples are indicative of the presence of recharge water that interacted with agricultural soils.