Summary recommendations on "Analytical methods for substances in the Watch List under the Water Framework Directive"

The Watch List (WL) is a monitoring program under the European Water Framework Directive (WFD) to obtain high-quality Union-wide monitoring data on potential water pollutants for which scarce monitoring data or data of insufficient quality are available. The main purpose of the WL data collection is to determine if the substances pose a risk to the aquatic environment at EU level and subsequently to decide whether a threshold, the Environmental Quality Standards (EQS) should be set for them and, potentially to be listed as priority substance in the WFD. The first WL was established in 2015 and contained 10 individual or groups of substances while the 4th WL was launched in 2022. The results of monitoring the substances of the first WL showed that some countries had difficulties to reach an analytical Limit of Quantification (LOQ) below or equal to the Predicted No-Effect Concentrations (PNEC) or EQS. The Joint Research Centre (JRC) of the European Commission (EC) organised a series of workshops to support the EU Member States (MS) and their activities under the WFD. Sharing the knowledge among the Member States on the analytical methods is important to deliver good data quality. The outcome and the discussion engaged with the experts are described in this paper, and in addition a literature review of the most important publications on the analysis of 17-alpha-ethinylestradiol (EE2), amoxicillin, ciprofloxacin, metaflumizone, fipronil, metformin, and guanylurea from the last years is presented.

Holistic approach to chemical and microbiological quality of aquatic ecosystems impacted by wastewater effluent discharges

Wastewater treatment plants (WWTPs) collect wastewater from various sources and use different treatment processes to reduce the load of pollutants in the environment. Since the removal of many chemical pollutants and bacteria by WWTPs is incomplete, they constitute a potential source of contaminants. The continuous release of contaminants through WWTP effluents can compromise the health of the aquatic ecosystems, even if they occur at very low concentrations. The main objective of this work was to characterize, over a period of four months, the treatment steps starting from income to the effluent and 5 km downstream to the receiving river. In this context, the efficiency removal of chemical pollutants (e.g. hormones and pharmaceuticals, including antibiotics) and bacteria was assessed in a WWTP case study by using a holistic approach. It embraces different chemical and biological-based methods, such as pharmaceutical analysis by HPLC-MSMS, growth rate inhibition in algae, ligand binding estrogen receptor assay, microbial community study by 16S and shotgun sequencing along with relative quantification of resistance genes by quantitative polymerase chain reaction. Although both, chemical and biological-based methods showed a significant reduction of the pollutant burden in effluent and surface waters compared to the influent of the WWTP, no complete removal of pollutants, pathogens and antibiotic resistance genes was observed.

Pathogenic, Morphological, and Phylogenetic Characterization of Fusarium solani f. sp. cucurbitae Isolates From Cucurbits in Almería Province, Spain

Fusarium solani f. sp. cucurbitae (syn. Neocosmosporum cucurbitae) is one of the most devastating soilborne pathogens affecting the production of cucurbits worldwide. Since its first detection in Almería Province in Spain in the spring of 2007, it has become one of the main soilborne pathogens affecting zucchini production. It has also been reported on melon, watermelon, and squash rootstocks in Spain, representing a high risk of dissemination in the area. The objectives of this study were to investigate the incidence and distribution of this disease in southeastern Spain and characterize isolates collected over 5 years. These strains were characterized on the basis of greenhouse aggressiveness assays on a range of cucurbit hosts, morphological characteristics, and elongation factor 1-α and RNA polymerase II second largest subunit phylogenies. All pathogenic isolates were highly aggressive on zucchini plants, causing a high mortality rate a few weeks after inoculation. The rest of the cucurbit hosts showed differential susceptibility to the pathogen, with cucumber being the least susceptible. Plants belonging to other families remained asymptomatic. Morphological characterization revealed the formation of verticilate monophialides and chlamydospores forming long chains, characteristics not described for this forma specialis. Phylogenetic studies of both the individual loci and combined datasets revealed that all pathogenic isolates clustered together with strong monophyletic support, nested within clade 3 in the F. solani species complex.

Survival of Fusarium solani f. sp. cucurbitae and Fungicide Application, Soil Solarization, and Biosolarization for Control of Crown and Foot Rot of Zucchini Squash

Fusarium crown and foot rot of zucchini squash (Cucurbita pepo L.) caused by Fusarium solani f. sp. cucurbitae is one of the major diseases affecting zucchini squash production in Almería, Spain. Experiments were conducted to determine the pathogen's ability to survive in infested bags of perlite and to test several control methods under greenhouse conditions. The pathogen survived in the bags for at least 20 months with enough inoculum at that time to produce disease symptoms in zucchini plants, although disease severity was significantly reduced after 14 months. A total of 14 zucchini cultivars were inoculated with F. solani f. sp. cucurbitae, and all were highly susceptible to the disease. Eight fungicides and two microbial products, Trichoderma harzianum and Rhizophagus irregularis, were tested to determine their efficacy for the control of this disease. Prochloraz, carbendazim, and thiophanate-methyl, which are not labeled for use in zucchini in Spain, were highly effective for the control of the disease, while the other products were ineffective. Two soil solarization and biosolarization experiments were conducted in a greenhouse for 45-day periods during the summer. Inocula in the soil samples decreased by more than 99%, indicating the efficacy of completely closing the greenhouse windows, solarization, and biosolarization in reducing inoculum. Fungicide applications, crop rotation for at least two years, and soil solarization or biosolarization are promising control methods for this disease.

Monitoring Lysobacter capsici AZ78 using strain specific qPCR reveals the importance of the formulation for its survival in vineyards

Survival in the phyllosphere is a critical feature for biofungicides based on non-spore forming bacteria. Moreover, knowledge of their persistence on plants is important to design effective formulations and application techniques. With this scope, the aim of this work was to develop a specific method to monitor the fate in the environment of Lysobacter capsici AZ78, a biocontrol agent of Plasmopara viticola, and to evaluate the contribution of formulation in its persistence on grapevine leaves. A strain-specific primer pair derived from REP-PCR fingerprinting was used in quantitative PCR experiments to track the evolution of L. capsici AZ78 population in vineyards. The population reached between 5 and 6 log10 cells gram of leaf(-1) after application and decreased by more than 100 times in one week. Multiple regression analysis showed that unfavourable temperature was the main environmental factor correlating with the decrease of L. capsici AZ78 persistence on grapevine leaves. Importantly, the use of formulation additives protected L. capsici AZ78 against environmental factors and improved its persistence on the leaves by more than 10 times compared to nude cells. Formulation and the knowledge about the persistence of L. capsici AZ78 in vineyards will be useful to develop commercial biofungicides for foliar application.