Identifying sources and distribution of organic pollutants in a Moroccan river: Characterization of dissolved organic matter by absorption, excitation-emission fluorescence and chemometric analyses.

This study investigates surface water contamination of Ben-Kazza River in Morocco, fed by effluents from an adjacent lagoon-based wastewater treatment plant (WWTP) and seasonally by industrial effluents, and which occasionally serves to irrigate agricultural fields. This study has two purpose: i) to track the main sources of contamination through the evolution of dissolved organic matter (DOM) characteristics along the watercourse, and ii) to characterize the WWTP influents and effluents with a focus on the efficiency of the lagoon treatment. We characterized a total of 495 water samples across the watercourse and from the inlet and outlet of the WWTP, using UV-visible absorption and excitation-emission fluorescence coupled with chemometric analyses.

Characterizing environmental contamination by plant protection products along the land-to-sea continuum:a focus on France and French overseas territories.

Environmental compartments are contaminated by a broad spectrum of plant protection products (PPPs) that are currently widely used in agriculture or, for some of them, whose use was banned many years ago. The aim of this study is to draw up an overview of the levels of contamination of soils, continental aquatic environments, seawaters and atmosphere by organic PPPs in France and the French overseas territories, based on data from the scientific publications and the grey literature. It is difficult to establish an exhaustive picture of the overall contamination of the environment because the various compartments monitored, the monitoring frequencies, the duration of the studies and the lists of substances are not the same.

The use of copper as plant protection product contributes to environmental contamination and resulting impacts on terrestrial and aquatic biodiversity and ecosystem functions.

Copper-based plant protection products (PPPs) are widely used in both conventional and organic farming, and to a lesser extent for non-agricultural maintenance of gardens, greenspaces, and infrastructures. The use of copper PPPs adds to environmental contamination by this trace element. This paper aims to review the contribution of these PPPs to the contamination of soils and waters by copper in the context of France (which can be extrapolated to most of the European countries), and the resulting impacts on terrestrial and aquatic biodiversity, as well as on ecosystem functions.

Impacts of neonicotinoids on biodiversity: a critical review.

Neonicotinoids are the most widely used class of insecticides in the world, but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air.

Prediction of the accumulation behavior of pesticides in PDMS-coated stir bars used as passive samplers in freshwaters.

Passive samplers accumulate organic contaminants at rates that depend on in-field exposure conditions such as freshwater flow velocity, water temperature and water quality. Time-weighted average concentrations can be determined by using a correction process such as the performance reference compound (PRC) method. This study presented a new approach to predict the accumulation behavior of pesticides in polydimethylsiloxane-coated stir bars under different exposure conditions and assign a specific PRC to each pesticide for quantitative purposes.

PITCH: A model simulating the transfer and retention of pesticides in infiltrating ditches and channel networks for management design purposes.

Agricultural ditches are frequently included in the panel of landscape elements to be managed to minimize the negative impacts of agriculture on the environment, particularly water contamination. A new mechanistic model simulating pesticide transfer in ditch networks during flood events was developed for help in designing ditch management. The model considers pesticide sorption processes to soil, living vegetation and litter and is adapted to heterogeneous and infiltrating tree-like ditch networks, with a reach resolution.

Main conclusions and perspectives from the collective scientific assessment of the effects of plant protection products on biodiversity and ecosystem services along the land-sea continuum in France and French overseas territories.

Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020-2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services.

Enhanced database creation with in silico workflows for suspect screening of unknown tebuconazole transformation products in environmental samples by UHPLC-HRMS.

The search and identification of organic contaminants in agricultural watersheds has become a crucial effort to better characterize watershed contamination by pesticides. The past decade has brought a more holistic view of watershed contamination via the deployment of powerful analytical strategies such as non-target and suspect screening analysis that can search more contaminants and their transformation products. However, suspect screening analysis remains broadly confined to known molecules, primarily due to the lack of analytical standards and suspect databases for unknowns such as pesticide transformation products.

Combination of 3D Fluorescence/PARAFAC and UV-Vis Absorption for the Characterization of Agricultural Soils from Morocco.

The present study, combining UV-Visible absorption and 3D fluorescence supported by PARAFAC chemometric analysis, focused on the characterization of soil water extractable organic matter (WEOM) in the zone of Doukkala located near the Atlantic coast of Morocco. The extracts, in water, of a set of 30 samples covering the four main types of agricultural soils in the region (commonly labeled Tirs, Faid, Hamri and R'mel) were investigated. [Formula: see text] and [Formula: see text] absorbance ratios [Formula: see text] and [Formula: see text] spectral slopes, along with their ratios[Formula: see text], as well as the fluorescence [Formula: see text] and humification [Formula: see text] indices were calculated and interpreted.

The combination of chemical, structural, and functional indicators to evaluate the anthropogenic impacts on agricultural stream ecosystems.

Freshwater contamination by pesticides in agricultural landscapes is of increasing concern worldwide, with strong pesticide impacts on biodiversity, ecosystem functions, and ultimately human health (drinking water, fishing). In addition, the excessively large number of substances, as well as their low - and temporally variable - concentrations in water, make the chemical monitoring by grab sampling very demanding and not fully representative of the actual contamination. Tools that integrate temporal variations and that are ecologically relevant are clearly needed to improve the monitoring of freshwater contamination and assess its biological effects.

Inter-laboratory mass spectrometry dataset based on passive sampling of drinking water for non-target analysis.

Non-target analysis (NTA) employing high-resolution mass spectrometry is a commonly applied approach for the detection of novel chemicals of emerging concern in complex environmental samples. NTA typically results in large and information-rich datasets that require computer aided (ideally automated) strategies for their processing and interpretation. Such strategies do however raise the challenge of reproducibility between and within different processing workflows.

Suspect screening of environmental contaminants by UHPLC-HRMS and transposable Quantitative Structure-Retention Relationship modelling.

A Quantitative Structure-Retention Relationship (QSRR) model is proposed and aims at increasing the confidence level associated to the identification of organic contaminants by Ultra-High Performance Liquid Chromatography hyphenated to High Resolution Mass Spectrometry (UHPLC-HRMS) in environmental samples under a suspect screening approach. The model was built from a selection of 8 easily accessible physicochemical descriptors, and was validated from a set of 274 organic compounds commonly found in environmental samples. The proposed predictive figure approach is based on the mobile phase composition at solute elution (expressed as % acetonitrile), that has the major advantage of making the model reusable by other laboratories, since the elution composition is independent of both the column geometry and the UHPLC-system.

Scout-multiple reaction monitoring: A liquid chromatography tandem mass spectrometry approach for multi-residue pesticide analysis without time scheduling.

In this work, an innovative method is described for multi-residue pesticide analysis by liquid chromatography coupled to targeted mass spectrometry, called "Scout-MRM, this new acquisition mode relies on the monitoring by either endogenous or spiked Scout compounds, hence fully releasing the monitoring of target molecules from time scheduling. As a proof of concept, a Scout-MRM method was built where 5 transitions groups tracking a total of 191 pesticides where successively triggered under the control of 5 spiked-in deuterated pesticides. As expected from its retention time independency, Scout-MRM demonstrates strong detection robustness towards modifications of gradient parameters, as well as easy method transfer between distinct analytical platforms with nearly 100% recovery after a single run.

Role of Biofilms in Contaminant Bioaccumulation and Trophic Transfer in Aquatic Ecosystems: Current State of Knowledge and Future Challenges.

In freshwater environments, microbial assemblages attached to submerged substrates play an essential role in ecosystem processes such as primary production, supported by periphyton, or organic matter decomposition, supported by microbial communities attached to leaf litter or sediments. These microbial assemblages, also called biofilms, are not only involved in nutrients fluxes but also in contaminants dynamics. Biofilms can accumulate metals and organic contaminants transported by the water flow and/or adsorbed onto substrates.

Interactive Effects of Pesticides and Nutrients on Microbial Communities Responsible of Litter Decomposition in Streams.

Global contamination of streams by a large variety of compounds, such as nutrients and pesticides, may exert a high pressure on aquatic organisms, including microbial communities and their activity of organic matter decomposition. In this study, we assessed the potential interaction between nutrients and a fungicide and herbicide [tebuconazole (TBZ) and S-metolachlor (S-Met), respectively] at realistic environmental concentrations on the structure (biomass, diversity) and decomposition activity of fungal and bacterial communities (leaf decay rates, extracellular enzymatic activities) associated with () leaves. A 40-day microcosm experiment was used to combine two nutrient conditions (mesotrophic and eutrophic) with four pesticide treatments at a nominal concentrations of 15 μg L (control, TBZ and S-Met, alone or mixed) following a 2 × 4 full factorial design.

Calibration of silicone rubber rods as passive samplers for pesticides at two different flow velocities: Modeling of sampling rates under water boundary layer and polymer control.

There is a need to determine time-weighted average concentrations of polar contaminants such as pesticides by passive sampling in environmental waters. Calibration data for silicone rubber-based passive samplers are lacking for this class of compounds. The calibration data, sampling rate (R ), and partition coefficient between silicone rubber and water (K ) were precisely determined for 23 pesticides and 13 candidate performance reference compounds (PRCs) in a laboratory calibration system over 14 d for 2 water flow velocities, 5 and 20 cm s .

Combination of sorption properties of polydimethylsiloxane and solid-phase extraction sorbents in a single composite material for the passive sampling of polar and apolar pesticides in water.

Passive sampling techniques have been developed as an alternative method for in situ integrative monitoring of trace levels of neutral pesticides in environmental waters. The objective of this work was to develop a new receiving phase for pesticides with a wide range of polarities in a single step. We describe the development of three new composite silicone rubbers, combining polydimethylsiloxane mechanical and sorption properties with solid-phase extraction sorbents, prepared as a receiving phase for passive sampling.

Silicone rubber selection for passive sampling of pesticides in water.

Silicone rubber can extract organic compounds with a broad range of polarities (logKow>2-3) from aqueous samples. Such compounds include substances of major concern in the protection of aquatic ecosystems and human health, e.g.

How do PDMS-coated stir bars used as passive samplers integrate concentration peaks of pesticides in freshwater?

Passive samplers are theoretically capable of integrating variations of concentrations of micropollutants in freshwater and providing accurate average values. However, this property is rarely verified and quantified experimentally. In this study, we investigated, in controlled conditions, how the polydimethylsiloxane-coated stir bars (passive Twisters) can integrate fluctuating concentrations of 20 moderately hydrophilic to hydrophobic pesticides (2.

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition.

Loss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20μgL(-1)).

Field application of passive SBSE for the monitoring of pesticides in surface waters.

Spot sampling lacks representativeness for monitoring organic contaminants in most surface waters. Passive sampling has emerged as a cost-effective complementary sampling technique. We recently developed passive stir bar sorptive extraction (passive SBSE), with Twister from Gerstel, for monitoring moderately hydrophilic to hydrophobic pesticides (2.

Effects of mixtures of dissolved and particulate contaminants on phototrophic biofilms: new insights from a PICT approach combining toxicity tests with passive samplers and model substances.

Streams located in vineyard areas are particularly exposed to mixtures of dissolved and particulate contaminants such as metals and organic pesticides. In this context, phototrophic biofilms are increasingly used as indicators of river water contaminations through pollution-induced community tolerance (PICT) assessments based on short-term toxicity tests with individual or mixtures of toxicants. We conducted a laboratory experiment to evaluate the relative influence of the dissolved and particulate fractions on the effects of metals and pesticides on phototrophic biofilms in a context of contamination from a vineyard watershed.

Use of passive stir bar sorptive extraction as a simple integrative sampling technique of pesticides in freshwaters: determination of sampling rates and lag-phases.

Passive sampling represents a cost-effective approach and is more representative than grab sampling for the determination of contaminant concentrations in freshwaters. In this study, we performed the calibration of a promising tool, the passive stir bar sorptive extraction (SBSE), which has previously shown good performances for semi-quantitative monitoring of pesticides in a field study. We determined the sampling rates and lag-phases of 18 moderately hydrophobic to hydrophobic agricultural pesticides (2.

Use of experimental designs for the optimization of stir bar sorptive extraction coupled to GC-MS/MS and comprehensive validation for the quantification of pesticides in freshwaters.

Although experimental design is a powerful tool, it is rarely used for the development of analytical methods for the determination of organic contaminants in the environment. When investigated factors are interdependent, this methodology allows studying efficiently not only their effects on the response but also the effects of their interactions. A complete and didactic chemometric study is described herein for the optimization of an analytical method involving stir bar sorptive extraction followed by thermal desorption coupled with gas chromatography and tandem mass spectrometry for the rapid quantification of several pesticides in freshwaters.