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.

Adjuvants are supplemental substances added to pesticide tank mixtures to enhance their efficacy by altering the dispersing, emulsifying, spreading, sticking, and wetting properties of the spray mixture. The goals of this study were an assessment of the effectiveness of pyraclostrobin and boscalid against garlic rust; the fungicide’s dissipation and translocation within plant tissue in the presence of commercial adjuvants Dash^® HC EC; and the validation of an analytical method for concurrently determining boscalid and pyraclostrobin in green garlic and garlic bulbs. Pyraclostrobin and boscalid retention in green garlic and the dietary exposure risks were also evaluated. The adjuvant Dash^® HC EC is an emulsifiable concentrate containing fatty acids, methyl esters, and alkoxylated alcohol–phosphate esters. The test plots were sprayed with the maximum recommended dosage of 400.5 g a.i. ha⁻¹ boscalid and 100.5 g a.i. ha⁻¹ pyraclostrobin. The residues of pyraclostrobin and boscalid in garlic bulb and green garlic samples were determined using a mini-Luke multi-residue solvent extraction method paired with a high-performance liquid chromatography diode array detector (HPLC–DAD). This method is based on the extraction of a homogeneous sample with acetone, petroleum ether, and dichloromethane. Boscalid and pyraclostrobin recoveries in green garlic and garlic bulbs ranged from 71% to 107% on average, with a relative standard deviation (RSD) of 6.8% to 18.1%, and limits of quantification were 0.02 mg/kg. In green garlic and garlic bulbs, boscalid residues ranged from 0.14 to 3.51 mg/kg and pyraclostrobin from lower than LOQ to 1.43 mg/kg, during the experiment. The adjuvant increased the fungicidal efficacy of the fungicides and their retention on green garlic. Although boscalid is considered a nonsystemic fungicide, it showed higher translocation from garlic leaves to garlic bulbs than pyraclostrobin. Regarding the dietary risk assessment, the use of the adjuvant in a tank mixture with boscalid and pyraclostrobin is considered safe 14 days after application, which agrees with the recommended PHI.

The use of selective herbicides is one of the best methods for weed management. However, the extensive use of herbicides can have adverse impacts on non-target organisms. The goals of this study were to assess the dissipation kinetics, leaching, and ecological risk assessment of S-metolachlor and benfluralin residues in silty loam soil planted with chickpea (Cicer arietinum L.). The experimental setup included four different layers with four replications corresponding to an experimental randomized complete block design consisting of 16 plots. The application doses of S-metolachlor and benfluralin were 1350 and 1920 g a.i./ha, respectively, according to manufacturer recommendations. Soil samples were split into four depths, 0 to 20 cm (Layer A), 20 to 40 cm (Layer B), 40 to 60 cm (Layer C), and 60 to 80 cm (Layer D), to determine the dissipation kinetics and the leaching behavior of the herbicides. Gas chromatography coupled with the electron capture detector (GC-ECD) method was developed and validated for the determination of S-metolachlor and benfluralin residues in soil. The analytes were extracted from the soil with distilled water and ethyl acetate followed by solid-phase extraction (SPE). The limit of quantification (LOQ) of the method was 0.1 μg/g, and the recoveries of S-metolachlor and benfluralin were in the ranges 81% to 97% and 88% to 101%, respectively, with relative standard deviations (RSD) of less than 9.7%. The dissipation kinetics of S-metolachlor and benfluralin in soil (0–20 cm) followed first-order kinetics with half-lives of 21.66 and 30.13 days, respectively. The results for samples obtained from the 20–80 cm soil profile showed that both benfluralin and S-metolachlor presented high leaching, following preferential flow. Also, a soil ecological risk assessment was conducted in the top 0–20 cm soil profile, estimating the toxicity–exposure ratio (TER) for four soil organisms and the risk quotient (RQ). The mean herbicide levels found at the studied soil profile at 0 days (2 h) and 60 days of the experiment were used for risk assessment. In the first case, the mean pesticide concentration (MPC) gives a worst-case scenario (ws); in the second case, a dissipation scenario (ds) is given using the respective MPC. In all cases, both TER and RQ values showed that benfluralin corresponds to a higher risk than S-metolachlor for soil organisms.

The extensive use of fungicides causes their continuous release into the environment through spraying, soil seepage, leaching, and runoff. It has been observed that their residues can be found in foods and a variety of environmental compartments, such as wastewater, lakes, rivers, sediments, drinking water sources (groundwater and surface water), treated water, and drinking water. A sensitive GC-MS/MS, using dynamic multiple reaction monitoring, an analytical method was developed to determine 10 fungicides (azoxystrobin, boscalid, captan, cyproconazole, cyprodinil, hexaconazole, metalaxyl, myclobutanil, paclobutrazol, and prochloraz) in drinking water. A solid-phase extraction method for sample preparations and validations was performed according to SANTE 2019 guidelines. All fungicides demonstrated mild or medium matrix effects (ME) ranging from 40.1% to 11.2%. Their recoveries ranged between 60% and 110%. The limits of detection were equal to or higher than 0.01 μg/L. The method was employed on 18 drinking water samples collected from public taps in Northern Evros, Greece, distributed in six sampling sites. Azoxystrobin, boscalid, cyproconazole, cypronidil, metalaxyl, and paclobutrazol mean concentrations did not surpass the allowable limit of 0.1 μg/L set by EU in any sampling site. Hexaconazole mean concentrations were higher than 0.1 μg/L in one sampling site, while prochloraz mean concentration showed limit exceedances in all sampling sites. Captan was not detected in any sampling site, and myclobutanil mean concentrations demonstrated exceedances of the permissible limit in four sampling sites. The presence of fungicide residues in the studied area is mainly due to the occasional point-sources pollution and preferential flow. Additionally, through the use of water, the risk of pesticides to human health was assessed for two different age groups. The sum of the hazard quotient values in each of the studied drinking water was less than unity. Consequently, the acute risk assessment procedure regards the examined drinking water as safe. Nevertheless, as prochloraz carcinogenic risk values were higher than the safe limit suggested by USEPA for both age groups, the existence of prochloraz residues raises concerns about chronic toxicity.

Grape cultivation is crucial due to its significant dietary benefits and the production of various byproducts. Fungicides, like boscalid, are frequently applied to protect grape crops from several disease, ensuring both yield and quality. However, the excessive or inappropriate application of boscalid may pose health risks to humans. Therefore, the objectives of this field study were (a) to assess the pre-harvest interval (PHI) and dissipation of boscalid in two table-grape varieties (Soultanina and Crimson) under field conditions and (b) evaluate the potential health risks associated with grape consumption for both adults and children. The residue of boscalid in the grapes was determined using a modified QuEChERS method coupled with a high-performance liquid chromatography diode array detector (HPLC–DAD). The dissipation of boscalid followed first- and second-order kinetics, with half-lives ranging from 3.32 to 6.42 days and PHIs from 8.11 to 10.90 days. The dietary risk assessment indicated that the early to mid-post application period could pose risks for both age groups, with children facing three times the risk of adults.