Multi-residues analysis of pre-emergence herbicides in fluvial sediments: application to the mid-Garonne River

Abstract

Contamination of man and ecosystems by pesticides has become a major environmental concern. Whereas many studies exist on contamination from agriculture, the effects of urban sources are usually omitted. Fluvial sediment is a complex matrix of pollutants but little is known of its recent herbicide content. This study proposes a method for a fast and reliable analysis of herbicides by employing the accelerated solvent extractor (ASE). The aim of the study is to show the impact of a major town (Toulouse) on the herbicide content in the river. In this study, three herbicide families (i.e.s-triazine, substituted ureas and anilides) were analysed in fluvial sediment fractions at 11 sampling sites along the mid-Garonne River and its tributaries. River water contamination by herbicides is minor, except for at three sites located in urban areas. Among the herbicidal families studied, urban and suburban areas are distinguished from rural areas and were found to be the most contaminated sites during the study period, a winter low-water event. The herbicide content of the coarse sediment fractions is about one third of that found in the fine fractions and usually ignored. The distribution of pesticide concentrations across the whole range of particle sizes was investigated to clarify the role of plant remains on the significant accumulation in the coarse fractions.

The role of storm flows in concentration of pesticides associated with particulate and dissolved fractions as a threat to aquatic ecosystems - Case study: the agricultural watershed of Save river (Southwest of France)

“…Two sub-samples were put into glass bottles of 2.5 L (for pesticide and TSM analyses) and one into a glass bottle of 500 mL (for DOC and POC analyses). The first one was used for pesticide analyses in unfiltered water; dichloramethane (DCM) was added in the field (1:40 V/V) to inhibit microbial degradation of the pesticides (Kreuger, 1998;Devault et al, 2007) and also used for extraction in the laboratory. The second one was filtered on 0.45-µm cellulose ester Millipore filters for pesticide analyses in the filtrate after DCM extraction and for TSM measurements in the filters.…”

“…The selections of five families of pesticides were then further based on the study and on the availability of data of a 4-year-long study by Devault et al (2007). Pesticide analyses were performed by solvents of analytical grade (Pestipure by SDS, Solvent Documents Syntheses, Peypin, France).…”

“…Once the extraction was performed, dichloromethane was dried on 50 g anhydrous sodium sulphate, the remaining organic phase was evaporated under vacuum, and the dry residue was recuperated with 2 mL of hexane. Pesticide molecules (herbicides, fungicides) have been analysed by the multi-residue technique in filtered and unfiltered waters (Devault et al, 2007;Taghavi et al, 2010). Gas chromatography coupled to mass spectrometry was used for separation and detection of different components.…”

Herbicide Impact on Seagrass Communities

“…antifouling coatings and urban pesticide uses, and indirectly, but globally, altered by agricultural and urban chemical input due to landscape runoff and subsequent river pollution [55] and when groundwater tables well up through the soil directly at the sea (phenomenon known as Submarine Groundwater Discharge [56]). Their terrestrial impact is well known, as on soils, then on groundwater, surface water [3], sediments [57], biota [4] and human health [58].…”

Optimization Method for Simultaneous Extraction and Detection of Imazapic and Imazapyr Herbicides in Soil and Water Using HPLC-UV with Verification of LC-MS

“…Consumers are becoming more aware regarding the safety of food produced and thus the concerns on the effects of pesticides with regard to human health and the environment are no longer taken for granted (Wee 2005;Xavier et al 2004). Therefore, several studies have been conducted to determine herbicide residues in the urine of dairy cows (Krüger et al 2014), soil and water (Assalin et al 2014;Süzer & Büyük 2010), sediment (Devault et al 2007) as well as in vegetables (Lee et al 2015;SaitoShida et al 2016) with the use of High Performance For the recovery test, three different concentrations of imazapic and imazapyr, ie; 1, 5 and 10 mg L -1 were prepared. Each soil and water sample was treated with the combination of both imazapyr and imazapic.…”