Suchergebnisse

Abstract
Background
The European environmental risk assessment of plant protection products considers aquatic model ecosystem studies (microcosms/mesocosms, M/M) as suitable higher tier approach to assess treatment-related effects and to derive regulatory acceptable concentrations (RAC). However, it is under debate to what extent these artificial test systems reflect the risks of pesticidal substances with potential harmful effects on natural macroinvertebrate communities, and whether the field communities are adequately protected by the results of the M/M studies. We therefore compared the composition, sensitivity and vulnerability of benthic macroinvertebrates established in control (untreated) groups of 47 selected M/M studies with natural stream communities at 26 reference field sites.

Results
Since 2013 the number of benthic macroinvertebrate taxa present in M/M studies has increased by 39% to a mean of 38 families per study. However, there is only an average of 4 families per study that comply with the recommendations provided by EFSA (EFSA J 11:3290, 2013), i.e.: (i) allowing statistical identification of treatment-related effects of at least 70% according to the minimum detectable difference (here criteria are slightly modified) and (ii) belonging to insects or crustaceans (potentially sensitive taxa for pesticidal substances). Applying the criterion of physiological sensitivity according to the SPEARpesticides concept, the number of families decreases from 4 to 2.3 per study.

Conclusions
Most taxa established in recent M/M studies do not suitably represent natural freshwater communities. First, because their abundances are often not sufficient for statistical detection of treatment-related effects in order to determine an appropriate endpoint and subsequent RAC. Recommendations are given to improve the detectability of such effects and their reliability. Second, the taxa often do not represent especially sensitive or vulnerable taxa in natural communities in terms of their traits. The uncertainties linked to vulnerable taxa in M/M studies are especially high considering their representativity for field assemblages and the comparability of factors determining their recovery time. Thus considering recovery for deriving a RAC (i.e., ERO-RAC) is not recommended. In addition, this paper discusses further concerns regarding M/M studies in a broader regulatory context and recommends the development of alternative assessment tools and a shift towards a new paradigm.

Abstract
Background
With rapid industrial development, heavy metal contamination has become a major public health and ecological concern worldwide. Although knowledge about metal pollution in European water resources is increasing, monitoring data and assessments in developing countries are rare. In order to protect human health and aquatic ecosystems, it is necessary to investigate heavy metal content and its consequences to human health and ecology. Accordingly, we collected 200 water samples from different water resources including groundwater, canals, river and drains, and investigated metal contamination and its implications for human and ecological health. This is the first comprehensive study in the region that considered all the water resources for metal contamination and associated human health and ecological risks together.

Results
Here we show that the water resources of Lahore (Pakistan) are highly contaminated with metals, posing human and ecological health risks. Approximately 26% of the groundwater samples are unsuitable for drinking and carry the risk of cancer. Regarding dermal health risks, groundwater, canal, river, and drain water respectively showed 40%, 74%, 80%, and 90% of samples exceeding the threshold limit of the health risk index (HRI > 1). Regarding ecological risks, almost all the water samples exceeded the chronic and acute threshold limits for algae, fish, and crustaceans. Only 42% of groundwater samples were below the acute threshold limits. In the case of pollution index, 72%, 56%, and 100% of samples collected from canals, river Ravi, and drains were highly contaminated.

Conclusions
In conclusion, this comprehensive study shows high metal pollution in water resources and elucidates that human health and aquatic ecosystems are at high risk. Therefore, urgent and comprehensive measures are imperative to mitigate the escalating risks to human health and ecosystems.

AbstractExposure to pesticides may cause adaptation not only in agricultural pests and pathogens, but also in non-target organisms. Previous studies mainly searched for adaptations in non-target organisms in pesticide-polluted sites. However, organisms may propagate heritable pesticide effects, such as increased tolerance, to non-exposed populations through gene flow. We examined the pesticide tolerance—as one of the pre-assumptions of local adaptation—of the freshwater crustacean Gammarus spp. (at genus level reflecting the gammarid community). The pesticide tolerance was quantified in acute toxicity tests using the insecticide imidacloprid. Gammarids were sampled at pesticide-polluted agricultural sites (termed agriculture), least impacted upstream sites (termed refuge) and transitional sites (termed edge) in six small streams of south-west Germany. Furthermore, we examined the population genetic structure of Gammarus fossarum and the energy reserves (here lipid content) of G. fossarum as well as of Gammarus spp. at the three site types (i.e. agriculture, edge and refuge). We found significantly lower imidacloprid tolerance of Gammarus spp. from agricultural sites compared to edge and refuge sites, potentially due to higher environmental stress at agricultural sites, as indicated by a slightly lower lipid content per mg gammarid tissue. We found no differences in pesticide tolerance between edge and refuge populations, indicating no propagation of pesticide effects to edges. The genetic structure among G. fossarum populations showed significant differentiation between streams, but not within a stream across the site types. We suggest that high gene flow within each stream hindered population differentiation and resulted in similar (pre)adaptations to local stress levels between site types, although they exhibited different pesticide pollution. Further studies on target genes (e.g., conferring pesticide tolerance), population structure and fitness of different phenotypes in particular among non-target organisms are required for adjacent pristine ecosystems to detect potential propagations of pesticide effects.

Today's agriculture heavily relies on pesticides to manage diverse pests and maximise crop yields. Despite elaborate regulation of pesticide use based on a complex environmental risk assessment (ERA) scheme, the widespread use of these biologically active compounds has been shown to be a threat to the environment. For surface waters, pesticide exposure has been observed to exceed safe concentration levels and negatively impact stream ecology leading to the question whether current ERA schemes ensure a sustainable use of pesticides. To answer this, the large-scale "Kleingewässer-Monitoring" (KgM) assessed the occurrence of pesticides and related effects in 124 streams throughout Germany, Central Europe, in 2018 and 2019. Based on five scientific publications originating from the KgM, this thesis evaluated pesticide exposure in streams, ecological effects and the regulatory implications. More than 1,000 water samples were analysed for over 100 pesticide analytes to characterise occurrence patterns (publication 1). Measured concentrations and effects were used to validate the exposure and effect concentrations predicted in the ERA (publication 2). By jointly analysing real-world pesticide application data and measured pesticide mixtures in streams, the disregard of environmental pesticide mixtures in the ERA was evaluated (publication 3). The toxic potential of mixtures in stream water was additionally investigated using suspect screening for 395 chemicals and a battery of in-vitro bioassays (publication 4). Finally, the results from the KgM stream monitoring were used to assess the capability to identify pesticide risks in governmental monitoring programmes (publication 5). The results of this thesis reveal the widespread occurrence of pesticides in non-target stream ecosystems. The water samples contained a variety of pesticides occurring in complex mixtures predominantly in short-term peaks after rainfall events (publications 1 & 4). Respective pesticide concentration maxima were linked to declines in vulnerable invertebrate species and exceeded regulatory acceptable concentrations in about 80% of agricultural streams, while these thresholds were still estimated partly insufficient to protect the invertebrate community (publication 2). The co-occurrence of pesticides in streams led to a risk underestimated in the single substance-oriented ERA by a factor of about 3.2 in realistic worst-case scenarios, which is further exacerbated by a high frequency at which non-target organism are exposed to pesticides (publication 3). Stream water samples taken after rainfall caused distinct effects in bioassays which were only explainable to a minor extent by the many analytes, indicating the relevance of unknown chemical or biological mixture components (publication 4). Finally, the regulatory monitoring of surface waters under the Water Framework Directive (WFD) was found to significantly underestimate pesticide risks, as about three quarters of critical pesticides and more than half of streams at risk were overlooked (publication 5). Essentially, this thesis involves a new level of validation of the ERA of pesticides in aquatic ecosystems by assessing pesticide occurrence and environmental impacts at a scale so far unique. The overall results demonstrate that the current agricultural use of pesticides leads to significant impacts on stream ecology that go beyond the level tolerated under the ERA. This thesis identified the underestimation of pesticide exposure, the potential insufficiency of regulatory thresholds and the general inertia of the authorisation process as the main causes why the ERA fails to meet its objectives. To achieve a sustainable use of pesticides, the thesis proposes substantial refinements of the ERA. Adequate monitoring programmes such as the KgM, which go beyond current government monitoring efforts, will continue to be needed to keep pesticide regulators constantly informed of the validity of their prospective ERA, which will always be subject to uncertainty.

Abstract
Background
Many aquatic insects emerge as adults from water bodies to complete parts of their life cycle in terrestrial ecosystems and are potential prey for riparian predators. The benefits of riparian predators from aquatic insects include higher contents of long-chain polyunsaturated fatty acids (PUFA) compared to terrestrial insects. Aquatic insects are therefore considered a high-quality food. Food containing high levels of PUFA can enhance growth and immune response of spiders. However, agricultural stressors like nutrient increase, pesticides and habitat degradation can affect the biomass of aquatic insects and in turn the diet of spiders. Studies quantifying the influence of land use on fatty acid (FA) profiles of emergent aquatic insects and riparian predators are lacking. We quantified differences in exports of FA, saturated FA, monounsaturated FA, and PUFA, FA profiles of aquatic insects and spiders between forested and agricultural sites over the primary emergence period within one year. The FA export to the riparian food web is crucial to understand energy fluxes between ecosystems. Furthermore, we monitored environmental variables to identify associations between agricultural stressors and FA profiles of aquatic insects and spiders.

Results
We found differences in FA export and profiles of aquatic insects between land-use types. The quantity of total FA export via aquatic insects was lower in agricultural sites (95% CI 1147–1313 µg m−2) in comparison to forested sites (95% CI 1555–1845 µg m−2), while the biomass export was higher in agricultural sites. Additionally, in spring the PUFA export was significantly lower (up to 0.06 µg d−1 m−2) in agricultural than forested sites. Agricultural stressors explained only little variation in the FA profiles of aquatic insects, e.g., 4% for caddisflies and 12% for non-biting midges. Percentage of shading and pool habitats were identified as most important variables explaining the variation in FA profiles.

Conclusion
The quality of aquatic insects as food source for riparian spiders was smaller in agricultural than forested sites, which can decrease the fitness of riparian predators. To improve our capacity to predict potential adverse effects in the riparian food web, future studies should identify the mechanisms underlying a lower PUFA content.

Agrochemicals, such as pesticides and fertilizers, have facilitated an unprecedented intensification of agriculture [1, 2]. However, the desired yield gains come at the cost of unwanted side effects on the environment. Pesticides have been demonstrated to contribute to the decline of non-target organisms, such as bees, birds and aquatic biodiversity [3, 4, 5], fueling the global biodiversity crisis. This runs contrary to global efforts to protect biodiversity and, in particular, also to the aims of the European Union's (EU) pesticide regulation [6]. Consistent exceedances of regulatory thresholds [7] and revisions of authorizations of pesticides, such as of neonicotinoid insecticides in the EU by the Standing Committee on plants, animals, food and feed (PAFF Committee), also attest to deficiencies in regulatory pesticide risk assessment and management. ; ISSN:2190-4715 ; ISSN:2190-4707

Abstract
Background
Within the last decades, there has been increasing research on the occurrence of chemicals of emerging concern (CECs) in aquatic ecosystems due to their potential adverse effects on freshwater organisms and risk to human health. However, information on CECs in freshwater environments in sub-Saharan countries is very limited. Here, we investigated the occurrence of CECs in snails and sediments collected from 48 sites within the Lake Victoria South Basin, Kenya, which have been previously investigated for water contamination. Samples were analyzed by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) with a target list of 429 compounds.

Results
In total, 30 compounds have been detected in snails and 78 in sediment samples, compared to 79 previously identified compounds in water. By extending the monitoring of CECs to snails and sediments, we found 68 compounds that were not previously detected in water. These compounds include the anti-cancer drug anastrozole, detected for the first time in the Kenyan environment. Individual compound concentrations were detected up to 480 ng/g wet weight (N-ethyl-o-toluenesulfonamide) in snails and 110 ng/g organic carbon (pirimiphos-methyl) in sediments. Higher contaminant concentrations were found in agricultural sites than in areas not impacted by anthropogenic activities. Crustaceans were the organisms at greatest toxic risk from sediment contamination [toxic unit (TU) up to 0.99] with diazinon and pirimiphos-methyl driving this risk. Acute and chronic risks to algae were driven by diuron (TU up to 0.24), whereas fish were found to be at low-to-no acute risk (TU up to 0.007).

Conclusions
The compound classes present at the highest frequencies in all matrices were pesticides and biocides. This study shows substantial contamination of surface water in rural western Kenya. By filling data gaps on contamination of sediments and aquatic biota, our study reveals that CECs pose a substantial risk to environmental health in Kenya demanding for monitoring and mitigation.

Abstract
Background
Schistosomiasis is a neglected tropical disease caused by trematodes of the genus Schistosoma. The pathogen is transmitted via freshwater snails. These snails are highly tolerant to agricultural pesticides and indirectly benefit from exposure due to adverse effects on their more sensitive enemy species. Pesticides in surface waters may thus increase the risk of schistosomiasis transmission unless they also affect the pathogen. We tested the tolerance of the free-swimming life stages (miracidia and cercariae) of Schistosoma mansoni to the insecticides diazinon and imidacloprid. We also investigated whether these pesticides decrease the ability of miracidia to infect and further develop as sporocysts within the host snail Biomphalaria pfeifferi.

Results
Exposure to imidacloprid for 6 and 12 h immobilized 50% of miracidia at 150 and 16 µg/L, respectively (nominal EC50); 50% of cercariae were immobilized at 403 and 284 µg/L. Diazinon immobilized 50% of miracidia at 51 and 21 µg/L after 6 and 12 h; 50% of cercariae were immobilized at 25 and 13 µg/L. The observed insecticide tolerance is lower than those of the host snail B. pfeifferi and comparable to those of other commonly tested freshwater invertebrates. Exposure for up to 6 h decreased the infectivity of miracidia at high sublethal concentrations (48.8 µg imidacloprid/L and 10.5 µg diazinon/L, i.e. 20–33% of EC50), but not at lower concentrations commonly observed in the field (4.88 µg imidacloprid/L and 1.05 µg diazinon/L). The development of sporocysts within the snail host was not affected at any of these test concentrations.

Conclusions
Insecticides did not affect the performance of S. mansoni at environmentally relevant concentrations. Particularly within its host snail the pathogen can escape exposure peaks that have been shown to affect other sensitive invertebrates and their biological control of host snails. Our findings suggest that freshwater pollution with agricultural pesticides increases the risk of schistosomiasis; they illustrate the need to integrate an environmental and public health risk assessment and management.

Abstract
Background
Pesticides are washed from agricultural fields into adjacent streams, where even short-term exposure causes long-term ecological damage. Detecting pesticide pollution in streams thus requires the expensive monitoring of peak concentrations during run-off events. Alternatively, exposure and ecological effects can be assessed using the SPEARpesticides bioindicator that quantifies pesticide-related changes in the macroinvertebrate community composition. SPEARpesticides has been developed in Central Europe and validated in other parts of Europe, Australia and South America; here we investigated its performance in East African streams.

Results
With minimal adaptations of the SPEARpesticdes index, we successfully characterized pesticide pollution in 13 streams located in Western Kenya. The East African SPEARpesticides index correlated well with the overall toxicity of 30 pesticides (maximum toxic unit = maximum environmental vs. median lethal concentration) measured in stream water (R2 = 0.53). Similarly, the SPEARpesticides index correlated with the risk of surface run-off from agricultural fields (as identified based on ground slope in the catchment area and the width of protective riparian strips, R2 = 0.45). Unlike other bioindicators designed to indicate general water pollution, SPEARpesticides was independent of organic pollution and highly specific to pesticides. In 23% of the streams, pesticides exceeded concentrations considered environmentally safe based on European first tiered risk assessment.

Conclusions
Increasing contamination was associated with considerable changes in the macroinvertebrate community composition. We conclude that pesticides need to be better regulated also in developing countries. SPEARpesticides provides a straightforward and cost-efficient tool for the required monitoring of pesticide exposure in small to medium streams.

Mechanistic effect models have become increasingly popular for use in the frame of the environmental risk assessment of plant protection products and the active substances therein (summarized as pesticides). In 2018, the EFSA Panel on Plant Protection Products and their Residues (PPR) considered TKTD models of the GUTS family. fit for the modelling of acute mortality from pesticide exposure in aquatic ecosystems. Additionally, specialized dynamic energy budget models (DEBtox) for sublethal effects and a number of population models are currently under development for use in Higher Tier studies for risk assessment. The use of such models is expected to increase in the near future, but leaves numerous open questions to risk assessors, modelers, applicants and the public. In this report we thus provide a scientific evaluation of mechanistic effect models and their use, especially in the context of their implementation in the environmental risk assessment (ERA) of pesticides. In Part 1 of the report, we briefly reviewed a number of ecological models that may be potentially interesting for use in ERA. In part 2, we evaluated in detail 11 models or model families that may be potentially suitable or have been already proposed by applicants for ERA. In part 3, we evaluated some applications of these models that have been submitted for ERA, usually as a refinement tool to demonstrate low risk of unacceptable effects. These case studies were provided by the German Federal Environmental Agency. Part 4 provides a general discussion on conclusions that can be drawn from the evaluations, along with some suggestions for future improvements in model development and their use in ERA. Results have been discussed at an international symposium on 19th and 20th of September 2019 in Berlin with experts in the field of work; the presentations and minutes are presetned in the annex.

Many plant protection products (PPPs) that are authorized in the European Union for agricultural and private use consist of more than one active substance. Combination products with several active ingredients are frequently used with other PPPs in tank mixtures in a spraying sequence of field applications. Therefore, the assessment of mixture toxicity effects under realistic treatment regimes presents an essential part for the environmental risk assessment of PPPs. Many studies have addressed effects of toxicant mixtures on various organisms and endpoints. The model of concentration addition (CA) seems in many cases able to predict the joint effect of toxicant mixtures, both for aquatic and terrestrial organisms. Nevertheless, there is still a lack of understanding regarding the predictability of mixture toxicity for chronic effects and effects at higher levels of biological organization in different environmental compartments. For this, we evaluated in the present COMBITOX project existing literature and available data. We also critically reviewed available models and approaches (i.e. HAIR 2014, SYNOPS-WEB, PRIME-beta etc.) regarding their usefulness for predicting the combined risk of treatment regimes for terrestrial and aquatic ecosystems. Furthermore, we analyzed an unique and large data set of actual PPP spray series from twelve different agricultural crops in Germany to determine crop specific treatment regimes. Four spray series were selected to quantify the additional environmental risk of treatment regimes compared to single applications of active substances. The additional risk was determined using the concept of the maximum cumulative ratio (ratio of the toxicity-exposure ratio, TER, of the most toxic substance in a mixture to the cumulative TER of all components in a mixture). Our analyses show that CA can predict chronic mixture toxicity at the individual level in many cases when toxicity data are based on chronic ECx values than less precise NOEC-values. In contrast, existing scientific literature and studies from regulatory databases hamper a clear statement on the applicability of concepts such as CA or independent action for the prediction of mixture effectson community endpoints. We further identified crop specific patterns especially in terms of applied PPP classes and treatment frequency. The risk assessment of the four spray series revealed an additional risk of treatment regimes with a median factor of 2.18 (50th percentile) to 5.26 (90th percentile) considering all investigated risk indicators and spray series. Finally, we developed a new approach, MITAS, to assess the time-dependent mixture exposure and toxicity in a treatment regime. We conclude that the additional risk of PPP applications in treatment regimes is ecotoxicologically relevant and must be considered for a protective risk assessment of PPPs. However, uncertainties remain regarding the influence of synergistic effects, indirect effects, seed coating, repeated exposure or environmental stressors on the impact of PPP treatment regimes.

Im Kleingewässermonitoring 2018/2019 wurde eine umfangreiche Datenbasis zum Belastungszustand kleiner Fließgewässer in der deutschen Agrarlandschaft mit Pflanzenschutzmitteln (PSM) geschaffen. Mit den hier dargestellten vertieften Analysen der Daten wurden die treibenden Faktoren für die Einträge von PSM in Gewässer, die Effektivität von Risikominderungsmaßnahmen sowie die Toxizität von Pestiziden allein und in Kombination im Gewässer untersucht. Es zeigte sich, dass Gewässerrandstreifen den PSM-Eintrag insbesondere für gering mobile Stoffe effektiv mindern können und, dass auch nur zeitweise wasserführende Gräben den PSM-Eintrag erhöhen. Die große Anzahl an zeitgleich gefundenen PSM-Wirkstoffen in den Gewässerproben verdeutlicht das zusätzliche Risiko durch PSM-Mischungen, was die Risikobewertung im Zulassungsverfahren von PSM bislang nicht berücksichtigt. Ein weiteres Gewässermonitoring in 2021 ergänzt die Daten des Kleingewässermonitorings. Es bildet Trends der inzwischen im Feldanbau verbotenen Neonicotinoide ab und zeigt die Bedeutung der als Ersatzstoff zunehmend verwendeten Pyrethroide. Eine erste Auswertung von Anwendungsdaten aus den Einflusskorridoren der Messstellen zeigt darüber hinaus die Abhängigkeit der in den Gewässern gefundenen Belastungen vom PSM-Einsatz. Diese Auswertungen unterstreichen das Potential und die Notwendigkeit der Verfügbarkeit von PSM-Anwendungsdaten für die Identifikation von Expositionstreibern und für die Überprüfung von Expositionsmodellen und Risikomanagement. Auf Grundlage der Ergebnisse werden Empfehlungen für ein angepasstes Monitoringkonzept gegeben.