Pesticide occurrence and distribution in fogwater collected at four sites at Strasbourg metropolitan between 2015 and 2021.

The presence of pesticides in fogwater plays a major role in accumulating relatively substantial levels of trace compounds due to their unique physico-chemical characteristics. The radiation wintertime fog in Alsace has been studied in the past few years (between 2015 and 2021) at four sites (Geispolsheim, Erstein, Strasbourg, and Cronenbourg). Fog samples are extracted using the liquid-liquid extraction (LLE) performed on the XTR Chromabond cartridge coupled with gas/liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS). The samples are found to be contaminated by 25 semi- and non-volatile currently-used and previously-banned pesticides (like procymidone) and 16 organochlorine pesticides (OCPs) at notable levels and high detection frequency (DF). The analysis also reveals that Cronenbourg is the most contaminated site (31.5 ± 3.0 µg. L-1), followed by Erstein (23.1 ± 17.0 µg. L-1), Strasbourg (23.0 ± 3.5 µg. L-1), and Geispolsheim (22.8 ± 7.7 µg. L-1). Pearson and principal component analyses (PCA) prove the simultaneous application of fungicides, insecticides, and herbicides, and their atmospheric transport, mainly through west-southern air currents, from highly impacted sites to near-by urban and less impact sites (Strasbourg and Cronenbourg). The levels of OCPs are found at lower concentrations at all sites than other pesticides, of which dichlorodiphenyltrichloroethane (DDT) and its metabolites have the highest contribution (27%), while hexachlorobenzene (HCB) has the least contribution (3%). Ratio analysis indicates the historical emission of DDTs, whereas a recent and local input of lindane and endosulfan has been observed.

Environmental occurrence, spatial distribution, and source identification of PAHs in surface and groundwater samples of Abou Ali River-North Lebanon.

This paper assesses the concentrations, spatial distribution, compositional patterns, and sources of polycyclic aromatic hydrocarbons (PAHs) in the dissolved aqueous phase along the Abou Ali River course. The 16 priority PAHs, listed by the USEPA, were investigated in surface- and groundwater samples for 2 years starting August 2015 and ending in March 2017. Statistical analysis was done by using the ANOVA test at p < 0.05. The spatial distribution analysis and illustration were done using the ARC GIS software. The total PAHs concentration in surface and groundwater samples varied between not detected to 15.162 ng mL-1 and not detected to 0.635 ng mL-1, respectively. The highest concentration of PAHs in surface water was observed at site S16, downstream of the river. However, the absence of PAHs was noticed at sites S1 and S2 of the upstream. The contamination levels of PAHs were found to be high in surface water samples, and low in groundwater samples. The 5- and 6-ring PAHs were the most abundant species among others in surface water samples, whereas the 3-ring PAHs were the most abundant in groundwater. Pyrogenic inputs deriving from fuel combustion, incineration, and miscellaneous burning were found to be the main PAH sources in surface and groundwater without ignoring the contribution of petrogenic inputs in some areas.

Spatio-temporal distribution and ecological risk assessment of pesticides in the water resources of Abou Ali River, Northern Lebanon.

The objective of this study is to assess the occurrence, spatial, and temporal distribution of forty-eight multiclass pesticides in surface and groundwater samples of the Abou Ali River, located in the North of Lebanon. A 3-year monitoring program (six batches from August 2015 to March 2017) was implemented, and thirty sampling points were selected along the river for analysis. The analysis was executed using a previously developed and optimized solid-phase micro-extraction (SPME) gas-chromatography-mass spectrometry (GC-MS) method. Statistical analysis, using Kolmogorov-Smirnov, Kruskal-Wallis, and Dunnet T3 multiple comparison tests, was applied to compare mean concentrations of pesticides between the different sampling sites and the batches taken. The pesticides that had the highest frequency of detection in the surface and groundwater samples were alachlor, α-endosulfan, and methomyl. For surface water samples, high mean concentrations were perceived for two stations in the upper stream (S5 and S7), two stations (S11 and S14) in the middle stream, and one station (S16) in the lower stream of the river. The highest mean concentrations were observed in October 2015 and August 2016, the time of the year which correlates with the period of pesticide application. Considering groundwater samples, high mean concentrations of pesticides were detected in sites G4, G9, G10, and G12 and during October 2015 and March 2016, following the rainy season. Ecotoxicological risk assessment using the risk quotient (RQ) methodology revealed high risk for five pesticides under average conditions and fourteen under extreme conditions. This study presents, for the first time, a statistical analysis showing the quantification of pesticides in the water resources of the Abou Ali River. In conclusion, it reveals the need to apply a complete pesticide monitoring program, not only for the Abou Ali River but for all the water resources in Lebanon.