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Recommendations for reducing micropollutants in waters

Residues of medicinal products, pesticides, biozides and other chemicals can adversely affect the environment and human health already in low concentrations. These micropollutants are increasingly detected in our waters not least due to improved analytics. Precautionary measures are needed to prevent future stresses on our waterbodies. Therefore, the German Environment Agency (⁠ UBA ⁠) has analysed entry pathways, named critical substance characteristics and proposed a combination of measures consisting of measures at the source, in use and for wastewater treatment serving the objective of comprehensive water protection. Veröffentlicht in Hintergrundpapier.

Evaluation of the risk for soil organisms under real conditions

In assessing the effects of plant protection products (PPP) on organisms in soil it is crucial to predict accurately the environmental concentration (PECsoil) which organisms are exposed to. The PECsoil is depending on the spatial and temporal distribution of the PPP, arising from characteristics of the chemical (e.g. Kow, water solubility, degradability) and from soil parameters (e.g. pH value, TOC, texture). The potential effects of PPP on soil organisms depend -besides the concentration of the chemical in the soil matrix- on the spatial and temporal distribution of the animals, i.e., their exposure as well as their specific sensitivity to the chemical. A new approach for deriving environmental concentrations in soil is currently under discussion, taking the preferred soil depth of the organisms into account. We conducted two different outdoor studies in Terrestrial Model Ecosystems (TMEs) to monitor (1) the movement of pesticides in soil over time and (2) the exposure and effects on soil organisms during the same time. Additionally, an indoor TME study was conducted to measure the fate of the radiolabelled pesticides and the formation of non-extractable resi-dues in soil. In study [1] (outdoor) and [2] (indoor) Lindane (log Kow > 3) and Imidacloprid (log Kow < 1) were applied, two pesticides with different physico-chemical properties. In study [3] (outdoor), we investigated the effects of Carbendazim, a pesticide which is known as to be toxic for earthworms at certain concentrations. The effect analysis was conducted by means of different multivariate and univariate statistical methods. The synergistic conclusions based on the project results are proposed as recommendations for risk assessment concerning exposure and risk of soil organisms exposed to PPP under realistic conditions. Quelle: Forschungsbericht

Width of vegetated buffer strips to protect aquatic life from pesticide effects

Vegetated buffer strips (VBS) are an effective measure to retain pesticide inputs during rain events. Numerous studies have examined the retention effects of VBS onpesticides. However, no study has addressed on a large scale with event-related peak concentrations how wide the VBS should be to avoid ecological impacts onaquatic life. Here, we investigated for 115 lowland stream sections in Germany the relevance of environmental and physico-chemical parameters to determine the in-stream pesticide concentration and their ecological risks. Based on peak concentrations related to rain events with precipitation amount resulting in VBS relevantsurface runoff for 30 of the 115 investigated stream sections (25 to 70 mm/d), we demonstrated that the average width of VBS was the main parameter (R2 = 0.38)reducing the pesticide input ratio, indicating a relevant proportion of surface runoff contributing to the total in-stream pesticide concentrations. Additionally, dryditches within agricultural fields increased pesticide input (R2 = 0.31). Generally, substances classified as slightly mobile were better retained by VBS than mobilesubstances. Other factors including slope, land use and vegetation cover of VBS had only a minor influence. We assessed the ecological risk of in-stream pesticideconcentrations by quantifying exceedances of regulatory- (RAC) and field-validated acceptable concentrations (ACfield). We then translated this ecological risk intoprotective VBS width by calculating the quotient of in-stream concentration and threshold (RQ). We estimate that a VBS width of 18 m is sufficient to meet theRQACfield protection goal for 95% of streams. The presence of dry ditches increased the protective VBS width to 32 m. In current agricultural practice, however, 26%of the water stretches investigated do not comply with the prescribed 5 m VBS. An extension of the VBS area to 18 m would demand 3.8% of agricultural land withinthe catchments. A 50% reduction in pesticide use, as required by the European green deal, would still result in 39% (RAC) and 68% (ACfield) of event-related samplesbeing exceeded. Consequently, we see the extension of the VBS width as the most efficient mearsure to sustainably reduce pesticide concentrations in small streams. © 2023 Elsevier

Pesticides in European rivers, lakes and groundwaters - data assessment

Pesticides play an important role in the food production process, but they can also lead to harmful effects in the environment. This report provides an overview of the available information on pesticide concentrations in fresh waters and groundwaters in Europe. The report considers data comparable at European level, delivering a detailed summary of data reported to WISE-SoE by Eionet countries, for concentrations in rivers, lakes and groundwater between 2007 - 2017. This includes information on 180 substances, which were characterised according to usage, mode of action, environmental quality standards and analytical limits of quantification. Other data sources, like scientific research projects, special campaigns or emission data were found to be less useful for a Europe-wide assessment. For rivers and lakes over the period 2007 - 2017, between 5 - 15 % of the monitoring stations showed exceedances of environmental quality standards by herbicides and 3 - 8 % by insecticides. Exceedances in groundwater were 7 % for herbicides and less than 1 % for insecticides. Exceedances were assessed using European environmental quality standards where possible, but otherwise a precautionary approach was taken, using national standards. By comparison, percentages of water body status as reported under the Water Framework Directive (2010 - 2015) were similar for groundwater, but for surface waters only 0.4% were reported as failing good status. The data quality assurance and assessment methods provide a sound basis for further work to develop an indicator on pesticides in water. ©European Topic Centre on Inland, Coastal and Marine waters (ETC/ICM), 2020

Three reasons why the Water Framework Directive (WFD) fails to identify pesticide risks

The Water Framework Directive (WFD) demands that good status is to be achieved for all European water bodies. While governmental monitoring under the WFD mostly concludes a good status with regard to pesticide pollution, numerous scientific studies have demonstrated widespread negative ecological impacts of pesticide exposure in surface waters. To identify reasons for this discrepancy, we analysed pesticide concentrations measured in a monitoring campaign of 91 agricultural streams in 2018 and 2019 using methodologies that exceed the requirements of the WFD. This included a sampling strategy that takes into account the periodic occurrence of pesticides and a different analyte spectrum designed to reflect current pesticide use. We found that regulatory acceptable concentrations (RACs) were exceeded for 39 different pesticides at 81% of monitoring sites. In comparison, WFD-compliant monitoring of the same sites would have detected only eleven pesticides as exceeding the WFD-based environmental quality standards (EQS) at 35% of monitoring sites. We suggest three reasons for this underestimation of pesticide risk under the WFD-compliant monitoring: (1) The sampling approach - the timing and site selection are unable to adequately capture the periodic occurrence of pesticides and investigate surface waters particularly susceptible to pesticide risks; (2) the measuring method - a too narrow analyte spectrum (6% of pesticides currently approved in Germany) and insufficient analytical capacities result in risk drivers being overlooked; (3) the assessment method for measured concentrations - the protectivity and availability of regulatory thresholds are not sufficient to ensure a good ecological status. We therefore propose practical and legal refinements to improve the WFD's monitoring and assessment strategy in order to gain a more realistic picture of pesticide surface water pollution. This will enable more rapid identification of risk drivers and suitable risk management measures to ultimately improve the status of European surface waters. © 2021 Elsevier Ltd.

Effects of multiple but low pesticide loads on aquatic fungal communities colonizing leaf litter

In the first tier risk assessment (RA) of pesticides, risk for aquatic communities is estimated by using results from standard laboratory tests with algae, daphnids and fish for single pesticides such as herbicides, fungicides, and insecticides. However, fungi as key organisms for nutrient cycling in ecosystems as well as multiple pesticide applications are not considered in the RA. In this study, the effects of multiple low pesticide pulses using regulatory acceptable concentrations (RACs) on the dynamics of non-target aquatic fungi were investigated in a study using pond mesocosm. For that, fungi colonizing black alder (Alnus glutinosa) leaves were exposed to multiple, low pulses of 11 different pesticides over a period of 60 days using a real farmer's pesticide application protocol for apple cropping. Four pond mesocosms served as treatments and 4 as controls. The composition of fungal communities colonizing the litter material was analyzed using a molecular fingerprinting approach based on the terminal Restriction Fragment Length Polymorphism (t-RFLP) of the fungal Internal Transcribed Spacer (ITS) region of the ribonucleic acid (RNA) gene(s). Our data indicated a clear fluctuation of fungal communities based on the degree of leaf litter degradation. However significant effects of the applied spraying sequence were not observed. Consequently also degradation rates of the litter material were not affected by the treatments. Our results indicate that the nutrient rich environment of the leaf litter material gave fungal communities the possibility to express genes that induce tolerance against the applied pesticides. Thus our data may not be transferred to other fresh water habitats with lower nutrient availability. Quelle: http://www.sciencedirect.com

Pesticides are the dominant stressors for vulnerable insects in lowland streams

Despite elaborate regulation of agricultural pesticides, their occurrence in non-target areas has been linked to adverse ecological effects on insects in several field investigations. Their quantitative role in contributing to the biodiversity crisis is, however, still not known. In a large-scale study across 101 sites of small lowland streams in Central Europe, Germany we revealed that 83% of agricultural streams did not meet the pesticide-related ecological targets. For the first time we identified that agricultural nonpoint-source pesticide pollution was the major driver in reducing vulnerable insect populations in aquatic invertebrate communities, exceeding the relevance of other anthropogenic stressors such as poor hydro-morphological structure and nutrients. We identified that the current authorisation of pesticides, which aims to prevent unacceptable adverse effects, underestimates the actual ecological risk as (i) measured pesticide concentrations exceeded current regulatory acceptable concentrations in 81% of the agricultural streams investigated, (ii) for several pesticides the inertia of the authorisation process impedes the incorporation of new scientific knowledge and (iii) existing thresholds of invertebrate toxicity drivers are not protective by a factor of 5.3 to 40. To provide adequate environmental quality objectives, the authorisation process needs to include monitoring-derived information on pesticide effects at the ecosystem level. Here, we derive such thresholds that ensure a protection of the invertebrate stream community. © 2021 Elsevier Ltd.

Effects of a realistic pesticide spraying sequence for apple crop on stream communities in mesocosms: negligible or notable?

Background Several large-scale studies revealed impacts and risks for aquatic communities of small rural lakes and streams due to pesticides in agricultural landscapes. It appears that pesticide risk assessment based on single products does not offer sufficient protection for non-target organisms, which are exposed repeatedly to pesticide mixtures in the environment. Therefore, a comprehensive stream mesocosm study was conducted in order to investigate the potential effects of a realistic spraying sequence for conventional orchard farmed apples on a stream community using pesticides at their regulatory acceptable concentrations (RACs). Eight 74-m-long stream mesocosms were established with water, sand, sediment, macrophytes, plankton and benthic macroinvertebrates. In total, nine fungicidal, four herbicidal and four insecticidal pesticides were applied in four of the eight stream mesocosms on 19 spraying event days in the period from April to July while the remaining four stream mesocosms served as controls. The community composition, the abundance of benthos, periphyton and macrophytes, the emergence of insects, physico-chemical water parameters, and drift measurements of aquatic invertebrates were measured. Results The pesticide spraying sequence induced significant effects on invertebrates, periphyton, and macrophytes as well as on the water ion composition especially in the second half of the experiment. It was not possible to relate the observed effects on the community to specific pesticides applied at certain time points and their associated toxic pressure using the toxic unit approach. The most striking result was the statistically significant increase in variation of population response parameters of some taxa in the treated mesocosms compared to the controls. This inter-individual variation can be seen as a general disturbance measure for the ecosystem. Conclusions The pesticide spraying sequence simulated by using RAC values had notable effects on the aquatic stream community in the conducted mesocosm study. The results indicate that the current risk assessment for pesticides may not ensure a sufficient level of protection to the field communities facing multiple pesticide entries due to spraying sequences and other combined stress. Hence, there is still room for improvement regarding the prospective risk assessment of pesticides to further reduce negative effects on the environment. © The Author(s) 2023

A multi-environmental tracer study to determine groundwater residence times and recharge in a structurally complex multi-aquifer system

Despite being the main drinking water resource for over 5 million people, the water balance of the Eastern Mountain Aquifer system on the western side of the Dead Sea is poorly understood. The regional aquifer consists of fractured and karstified limestone - aquifers of Cretaceous age, and it can be separated into a Cenomanian aquifer (upper aquifer) and Albian aquifer (lower aquifer). Both aquifers are exposed along the mountain ridge around Jerusalem, which is the main recharge area. From here, the recharged groundwater flows in a highly karstified aquifer system towards the east and discharges in springs in the lower Jordan Valley and Dead Sea region. We investigated the Eastern Mountain Aquifer system for groundwater flow, groundwater age and potential mixtures, and groundwater recharge. We combined 36Cl†â ̆Cl, tritium, and the anthropogenic gases SF6, CFC-12 (chlorofluorocarbon) and CFC-11, while using CFC-113 as "dating" tracers to estimate the young water components inside the Eastern Mountain Aquifer system. By application of lumped parameter models, we verified young groundwater components from the last 10 to 30 years and an admixture of a groundwater component older than about 70 years. Concentrations of nitrate, simazine (pesticide), acesulfame K (ACE-K; artificial sweetener) and naproxen (NAP; drug) in the groundwater were further indications of infiltration during the last 30 years. The combination of multiple environmental tracers and lumped parameter modelling helped to understand the groundwater age distribution and to estimate recharge despite scarce data in this very complex hydrogeological setting. Our groundwater recharge rates support groundwater management of this politically difficult area and can be used to inform and calibrate ongoing groundwater flow models. © Author(s) 2020

Recommendations for reducing micropollutants in waters

Residues of medicinal products, pesticides, biozides and other chemicals can adversely affect the environment and human health already in low concentrations. These micropollutants are increasingly detected in our waters not least due to improved analytics. Precautionary measures are needed to prevent future stresses on our waterbodies. Therefore, the German Environment Agency (⁠UBA⁠) has analysed entry pathways, named critical substance characteristics and proposed a combination of measures consisting of measures at the source, in use and for wastewater treatment serving the objective of comprehensive water protection.

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