Occurrence Of Pesticides In Groundwater Research Articles

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.

Multi-actor approach and engagement strategy to promote the adoption of best management practices and a sustainable use of pesticides for groundwater quality improvement in hilly vineyards

The adoption of pesticide mitigation measures and innovation at farm level, are seen as a drivers to reach the sustainable water policy objectives. With the aim to prevent the pesticide pressure of hilly vineyards on groundwater contamination, a stepwise approach in Tidone Valley was applied using different consultation mechanisms and involvement strategies throughout the overall process. Face to face meetings, direct surveys, participatory monitoring and planning of several activities aiming to inform, educate, improve skills, change of individual behaviour or raise awareness, or even initiatives to build institutional trust or support for new investment in innovation are some examples. These activities allowed us to involve key actors of water use and governance (such as farmers, advisors, representatives of drinking water management, farmer's associations, Winemaking cooperatives, local Health Authority), and to have a deeper knowledge of the context agricultural practices, of farmer's knowledge and skills concerning factors influencing water contamination and also to promote the most suitable Best Management Practices aimed at limiting the pesticide occurrence in groundwater. Indeed, the surveys results highlighted that the majority of the farms are small (64% of vineyards <10 ha), that most of the farmers (62%) are not aware of the current legislation on water, even if 64% of them declare to participate regularly to training courses for the prevention of water contamination and that there is a low to moderate level of adoption of Best Practices able to prevent contamination by pesticides. At the end of the overall process, it can be stated that the multi-actor approach and engagement strategy adopted were successful in improving attitudes to more sustainable practices. This is supported also by the monitoring data that show in 2019 a decrease by 44% of pesticides occurrences and a fall by 68% of values above EQSgw if compared with the period 2017–2018.

Occurrence of pesticides in Dutch drinking water sources

We determined pesticide occurrence in groundwater and surface water sources used for drinking water production in The Netherlands, using both routine monitoring data from Dutch drinking water companies and by studying the presence of newly authorized pesticides in drinking water sources.An analytical LC-MS/MS method was developed for 24 recently authorized pesticides, selected based on their mobility and persistence, and applied in a Dutch/Belgian ground- and surface water monitoring campaign. 15 of these pesticides were detected, including seven in concentrations above the water quality standard from the Water Framework Directive. Two neonicotinoids were detected in highest concentrations: acetamiprid (1.1 μg/L) and thiamethoxam (0.4 μg/L).The routine monitoring data was collected over 2010–2014 in The Netherlands, covering 408 pesticides and 52 metabolites. 63 pesticides and 6 metabolites were prioritized according to their presence in groundwater, surface water and drinking water. The vast majority of the pesticides in routine monitoring has not been detected or only in low concentrations.Overall, the study shows that pesticides are of major concern in drinking water sources across the Netherlands. In two third of the abstraction areas pesticides and/or metabolites have been detected. In one third of the abstraction areas pesticide and/or metabolites concentration exceeded water quality standards according to the Water Framework Directive. The results emphasize that monitoring should focus on priority pesticides, since the vast majority of the pesticides has a low priority. The occurrence of recently authorized pesticides in drinking water sources demonstrates the importance to keep routine monitoring methods up to date.

A new screening index for pesticides leachability to groundwater

Given the fact that pesticides exist in the aquatic environment at very low concentrations, it is clear that their analysis require expensive analytical techniques. Water authorities in Turkey are in need of assessing the likelihood of pesticide occurrence in groundwater in order to identify minimum number of pesticides that would be included in monitoring programs. To this purpose, the pesticides used in Turkey are ranked and those having higher leaching potentials are identified using pesticide screening leaching indexes. A total of 15 indexes (AF, AFR/AFT, Hamaker's RF, Briggs's RF, LPI, VI, LIX, GUS, Hornsby, LEACH, MLEACH, PLP, GWCP, LIN and GLI) was adopted and leaching potentials of 157 pesticides used in Turkey were estimated. Because each index is based on different pesticide/soil characteristics, each produced a different ranking. In order to emphasize variation in rankings and bring out a strong pattern, the statistical technique of Principal Component Analysis was used and a new composite index named as “YASGEP-P” was developed, the most relevant components (indices) were identified and the corresponding factor scores were calculated. This new index came out as a composite of GUS, LIX, MLEACH, LIN, Briggs's RF, Hamaker's RF, PLP and AFR indices. It was seen that all these indices except AFR are almost equally dominant and increase the value of YASGEP-P index, whereas AFR is also dominant but causes a decrease in YASGEP-P index value. The new index developed tends to discriminate between the relatively more soluble/less sorbable and more sorbable/less soluble pesticides. With the use of this composite index, the pesticides used in Turkey were sorted from the most leachable to least leachable and the priority pesticides to be monitored in the groundwaters were identified.

Phytoremediation of groundwater contaminated with pesticides using short-rotation willow crops: A case study of an apple orchard

ABSTRACTThe occurrence of pesticides in groundwater represents an important health issue, notably for population whose drinking water supply source is located in agricultural areas. However, few solutions have been considered with regard to this issue. We tested the efficacy of a vegetal filtering system made of shrub willows planted at a high density (16,000 plants ha−1) to filter or degrade pesticides found in the groundwater flowing out of an apple orchard. Ethylene urea (EU), ethylene thiourea (ETU), tetrahydrophthalimide (THPI), atrazine, and desethylatrazine were monitored in the soil solution in willow and control plots over one growing season. ETU and atrazine concentrations were lower in the willow plots relative to the control plots, whereas desethylatrazine concentration was higher in the willow plots. No significant difference was detected for EU and THPI. Furthermore, pesticide concentrations displayed complex temporal patterns. These results suggest that willow filter systems can filter or degrade pesticides, notably ETU and atrazine, and could be used for phytoremediation purposes. Yet, this potential remains to be quantified with further studies using experimental settings allowing more estimation in time and space.

Pesticide occurrence in groundwater and the physical characteristics in association with these detections in Ireland.

This study explores the associations of pesticide occurrence in groundwater to geological characteristics of the monitoring points (MPs) contributing area. Pesticide analyses were undertaken during a 2-year groundwater monitoring campaign which generated 845 samples. MCPA and mecoprop were the most frequently detected pesticides in groundwater. Each MP (n = 158) had a specifically delineated zone of contribution (ZOC) and the dominant physical characteristics present from nine national datasets were recorded for each ZOC. Associations between detections in groundwater and the dominant physical characteristic in each MPs ZOC tested were then statistically analyzed using Fisher's exact test, logistic regression, and multiple logistic regression. The original physical characteristic datasets used that were associated with detections in groundwater were the type of MP, aquifer type, and Quaternary deposit type. Logistic regression revealed that springs, regionally important aquifer types, aquifers with a karstic flow regime, and alkaline Quaternary deposits in existence above karst aquifers in a MP's ZOC were more likely to have a pesticide detection in groundwater. Multiple regression from this exploratory work showed some mutual dependency between soil association, aquifer type, and the Geological Survey of Ireland groundwater vulnerability map. The combination of national monitoring data and physical attribute datasets can be used to explore key areas where groundwater is more vulnerable to pesticide contamination.

Statistical screening for descriptive parameters for pesticide occurrence in a shallow groundwater catchment

Summary We have assessed the ability of a range of pesticide, site and climate parameters to discriminate between detected and non-detected pesticides as observed by long-term monitoring data of pesticide use and groundwater occurrence in a small catchment in southern Sweden. Of seventeen investigated parameters, six demonstrated such an ability: dosage applied, the Henry’s Law Constant (HLC), the octanol–water partitioning coefficient (log P ow ), the amount of precipitation the week before application, the amount of precipitation the month after application, and the substance degradation potential (DT 50 ). The apparent influence of the investigated parameters on pesticide occurrence in groundwater, and their apparent suitability as descriptive parameters in terms of assessment of related risks, is accordingly discussed. We conclude that knowledge of actual pesticide use appear fundamental for risk assessment of groundwater contamination potential. We further suggest that chemical property-parameters of specific pesticides, although clearly valuable, should be applied in groundwater contamination risk assessments with care. If site-specific values are unattainable, tabular values of log P ow , HLC and water solubility ( W s ) are demonstrated to exhibit a superior explanatory ability than those of substance adsorption potential ( K oc ) and DT 50 which, in the latter case, is shown to be able to lead to misleading conclusions on actual risks. The demonstrated explanatory ability of precipitation both before and after application suggests that relatively greater precipitation amounts occur in relation to application of non-detected substances. Increased dilution and run-off as well as decreased soil matrix retainment and decreased top-soil cracking are potential explanations although higher-resolution monitoring records are needed in order to confirm these hypotheses.

Présence de Pesticides dans l’Eau Souterraine en Milieu Agricole : Étude Pilote du Bassin Versant de la Rivière Châteauguay

The occurrence of pesticides in groundwater of the Chateauguay River watershed was investigated. The Chateauguay River is an important tributary of the St. Lawrence River. In this exploratory project, conducted between August and October 2005, water samples were collected from 57 rural domestic wells. Among them, 15 were located near apple orchards, 22 near vegetables production centres, and 20 near corn or soybean fields. In the Chateauguay River watershed, each type of crop is related to a specific hydrogeologic setting. Apple orchards are grown in sandy and gravelly soils in areas of moderate topography. Vegetables are grown in organic-rich soils, whereas corn and soybean are grown mainly in the clay-rich soils of the St. Lawrence plain. Low concentrations of pesticides were detected in 13 of the 57 wells sampled (23%); seven in clay soils near corn and soybean crops, and six in organic soils near vegetables crops. Surprisingly, no pesticides were detected in the wells situated in the most vulnerable zones near apple orchards. Detected pesticides include the herbicides atrazine, metolachlor, linuron, diuron, and metribuzin; the insecticides chlorpyrifos and diazinon; and the fungicide chlorothalonil. Concentrations for all pesticides detected in the wells are below drinking water guidelines.

Occurrence of Pesticides in Groundwater and Topsoil of the Gaza Strip

Agricultural activities in the Gaza Strip have been associated with excessive and uncontrolled use of dozens of pesticides. Accordingly, groundwater and soil are potentially contaminated causing severe threat to the crowded population. The present study describes a 3-year program to monitor types and levels of contamination by 52 pesticides in 94 groundwater wells in Gaza. Two analytical techniques (GC/MS and HPLC/MS) were applied to achieve this objective.

Pesticide fate at regional scale: Development of an integrated model approach and application

As a result of agricultural practice many soils and aquifers are contaminated with pesticides. In order to quantify the side-effects of these anthropogenic impacts on groundwater quality at regional scale, a process-based, integrated model approach was developed. The Richards’ equation based numerical model TRACE calculates the three-dimensional saturated/unsaturated water flow. For the modeling of regional scale pesticide transport we linked TRACE with the plant module SUCROS and with 3DLEWASTE, a hybrid Lagrangian/Eulerian approach to solve the convection/dispersion equation. We used measurements, standard methods like pedotransfer-functions or parameters from literature to derive the model input for the process model. A first-step application of TRACE/3DLEWASTE to the 20 km 2 test area ‘Zwischenscholle’ for the period 1983–1993 reveals the behaviour of the pesticide isoproturon. The selected test area is characterised by an intense agricultural use and shallow groundwater, resulting in a high vulnerability of the groundwater to pesticide contamination. The model results stress the importance of the unsaturated zone for the occurrence of pesticides in groundwater. Remarkable isoproturon concentrations in groundwater are predicted for locations with thin layered and permeable soils. For four selected locations we used measured piezometric heads to validate predicted groundwater levels. In general, the model results are consistent and reasonable. Thus the developed integrated model approach is seen as a promising tool for the quantification of the agricultural practice impact on groundwater quality.

Groundwater vulnerability: interactions of chemical and site properties

This study brings together extensive, multi-annual groundwater monitoring datasets from the UK and Midwestern US to test the relative importance of site (e.g. land use, soil and aquifer type) and chemical factors (e.g. solubility in water) and between and within year variations in controlling groundwater contamination by pesticides. ANOVA (general linear modelling) was used to test the significance and proportion of variation explained by each factor and their interactions. Results from both the UK and US datasets show that: (i) Chemical and site factors both have a statistically significant influence on groundwater pollution; (ii) Site factors on their own explain a greater proportion of data variance than chemical factors on their own; (iii) Interaction between site and chemical factors represents the most important control on the occurrence of pesticides in groundwater; (iv) Variation within the year was slight but still significant while there was no significant difference between data from consecutive years. The combination of factors analysed in this study were sufficient to explain the majority of the variation in the data save for that ascribable to the analytical detection limit. The results provide statistical evidence that it is viable to develop both molecular methods and groundwater vulnerability as tools to understanding pollution, but that a greater emphasis should be placed on their interaction to fully understand pesticide contamination.

Major herbicides in ground water: results from the National Water-Quality Assessment.

To improve understanding of the factors affecting pesticide occurrence in ground water, patterns of detection were examined for selected herbicides, based primarily on results from the National Water-Quality Assessment (NAWQA) program. The NAWQA data were derived from 2,227 sites (wells and springs) sampled in 20 major hydrologic basins across the USA from 1993 to 1995. Results are presented for six high-use herbicides--atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), cyanazine (2-[4-chloro-6-ethylamino-1,3,5triazin-2-yl]amino]-2-methylpropionitrile), simazine (2-chloro-4,6-bis-[ethylamino]-s-triazine), alachlor (2-chloro-N-[2,6-diethylphenyl]-N-[methoxymethyl]acetamide), acetochlor (2-chloro-N-[ethoxymethyl]-N-[2-ethyl-6-methylphenyl]acetamide), and metolachlor (2-chloro-N-[2-ethyl-6-methylphenyl]-N-[2-methoxylethyl]acetamide)--as well as for prometon (2,4-bis[isopropylamino]-6-methoxy-s-triazine), a nonagricultural herbicide detected frequently during the study. Concentrations were <1 microg L(-1) at 98% of the sites with detections, but exceeded drinking-water criteria (for atrazine) at two sites. In urban areas, frequencies of detection (at or above 0.01 microg L(-1)) of atrazine, cyanazine, simazine, alachlor, and metolachlor in shallow ground water were positively correlated with their nonagricultural use nationwide (P < 0.05). Among different agricultural areas, frequencies of detection were positively correlated with nearby agricultural use for atrazine, cyanazine, alachlor, and metolachlor, but not simazine. Multivariate analysis demonstrated that for these five herbicides, frequencies of detection beneath agricultural areas were positively correlated with their agricultural use and persistence in aerobic soil. Acetochlor, an agricultural herbicide first registered in 1994 for use in the USA, was detected in shallow ground water by 1995, consistent with previous field-scale studies indicating that some pesticides may be detected in ground water within 1 yr following application. The NAWQA results agreed closely with those from other multistate studies with similar designs.

The Occurrence of Pesticides in Groundwater—Results of Case-studies

Abstract A comparative review of pesticide survey endosing 16 waterworks in the FRG tries to increase the understanding about interferences of pesticide utilization and pesticide occurrence in ground- and drinkingwater, which includes characterization of sampling points, subsurface situation, land use and pesticide application. Between 1986 and 1991, 5772 samples were measured and led to 219094 data about the occurrence of various pesticides. 5% of these analyses showed pesticide or metabolite concentrations above the particular detection limits. This result does not vary in large extent considering groups of different characterized sampling points like groundwater dominated or surface water sampling points. As the herbicide atrazine and its metabolite desethylatrazine as well as the herbicide simazine were detected most often in all samples independent whether considering groundwater und surface water samples, this fact confirms the FRG-application ban for atrazine as well as the application restriction ...

Pesticides pollution of groundwater in the humid United States

Since 1980, many studies have begun to look at the occurrence of pesticides in groundwater; these range from controlled field/plot research studies, to simple monitoring of public water supplies to assess the occurrence of pesticides. The compounds most commonly detected are: (1) mobile and/or volatile soil fumigants and nematicides, used on vegetable or specialty crops; (2) commonly used herbicides from the humid corn-belt regions. The fumigants-nematicides have been the most widely looked for compounds. The herbicides commonly detected are also some of the most widely used of all pesticides, but pesticide properties clearly affect how commonly they are detected. In nearly all corn-belt areas, the herbicide atrazine is the most commonly detected compound. A general overview shows that a total of 39 pesticides have been detected in groundwater from 34 states or provinces. This includes occurrences related to commercial point sources (but not manufacturing sites, or detections exclusively referred to commercial sources) as well as nonpoint sources. From states with appropriate studies, there appears, within the context of pesticide properties, some general proportionality between pesticide use and detections in groundwater; this is also confounded by climatic differences. Kansas studies suggest that 8–10% of private, rural drinking-water supply wells, and 10% of susceptible public water-supply wells may exhibit pesticide contamination. Surveys in Minnesota and Iowa, with more intensive pesticide usage suggest that 20–30% of the more susceptible public water-supply wells, and 30–60% of private wells may exhibit pesticide residues. In contrast however, Illinois, a very high use state, has detected few pesticides in public water-supply wells (except where related to a commercial point source); why such differences occur among adjacent states is not clear. Pesticides are leaching through the soil and into groundwater far more commonly than the preconceptions of a decade ago would have predicted. Point sources may be widespread but are not the sole cause; it is also clear that many pesticides are leaching to groundwater from routine, nonpoint source use. Controlled plot studies show the intermittent, often rapid delivery of many pesticides to shallow groundwaters. The preferential flow of water and solutes through soil and rock materials clearly contributes to the delivery of pesticides to groundwater. The occurrence of preferential flow also implies that notions about the ‘relative susceptibility’ of various soils to pesticide leaching may not be accurate. Some studies show pesticide leaching more commonly in finer-textured soils than coarser, sandy textured soils. Generally, the concentrations of pesticides in groundwater are low, in the 0.1–5.0 μg l −1 range. Even at these concentrations there are concerns for long-term, chronic exposure to a large segment of the public through drinking-water supplies. While concerns with groundwater merit attention, the concentrations of pesticides in drinking water derived from surface waters will typically be greater. Current policy discussions often fail to understand the difference between groundwater protection and drinking-water protection programs and may not provide adequate protection for private rural groundwater supplies. Research and policies to resolve the problems of agricultural impacts on the environment will require a new focus on integrated farm-management systems, that enhance efficiency and reduce off-site impacts.

Potential contamination of ground water by pesticides

Abstract