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Seaweed has the potential to deliver more food to an increasing world population. Diseases endanger production security and yield of any farm, seaweed farming is no exception, hence crop protection plans may be developed that include the use of chemical crop protection either directly or indirectly in co-cropping systems. This document reports a first attempt to map the extent to which chemicals are being used in seaweed production, which production systems are used, where potential risks of the use of chemicals resulting from protection of seaweed production (or co-produced products) against diseases can be anticipated, and how this could be taken into account for future work. The investigations concerning open sea production systems indicate that for the control of pests and diseases in the described cultivation systems only prevention, monitoring and mechanical/physical measures are common, at least for Indonesia. In contrast, results from closed pond- or tank-based multi-trophic systems where seaweed can be included for example as feed or filter, or for biomass production, indicate some reasons for concern. Uptake and sorption of veterinary medicinal products and other chemicals can lead to additional input to shrimp and/or fish (via feed) or to the environment (via disposal of filter material). The ERA-AQUA model, originally developed for risk assessment of aquaculture production of fish and shrimp, was identified as possible means to further explore the fate of chemicals used in land-based multi-trophic production systems, for their bioaccumulation and biomagnification potential and possible risk for the environment, the produced goods (fish/shrimp), and finally human health.

Veterinary Medicinal Products (VMPs) are used in intensive aquaculture production to treat a wide range of bacterial and parasitic infestations. Their release into the environment poses concerns regarding their potential ecotoxicological risks to aquatic ecosystems, which need to be evaluated making use of appropriate Environmental Risk Assessment (ERA) schemes and models. This study presents an overview of the major aquaculture production systems in Europe, the VMPs most commonly used, and the environmental quality standards and regulatory procedures available for their ERA. Furthermore, it describes the state-of-the-art on the development of environmental models capable of assessing the fate, exposure, ecotoxicological effects and risks of VMPs in aquaculture production systems, and discusses their level of development and implementation within European aquaculture. This study shows that the use of environmental models in regulatory ERA is somewhat limited in many European countries. Major efforts have been dedicated to assess the fate and exposure of antiparasitic compounds in salmonid cage systems, particularly in Scotland, while models and scenarios for assessing dispersal of antimicrobials, in general, and antiparasitic compounds in the Mediterranean as well as in Scandinavian regions are less available. On the other hand, the use of ecological models for assessing the effects and risks of VMPs is almost absent. Recommendations are provided to improve the chemical exposure and effect assessments and the ecological realism of the modelling outcomes, paying special attention to the protection goals set for the regulatory ERA of VMPs in Europe.

This document describes suggestions for further steps that can be taken with regard to the evaluation of pest control products in Kenya. The document should be read together with the document describing proposed guidance on dossier evaluation for the registration of pest control products in Kenya and as such both contribute to a future complete pesticide evaluation manual for Kenya.Both documents were developed within the Pesticide management initiative East African Region: Kenya (PEAR -Kenya) project. The project ran in the period 2016 – 2019 and was sponsored and supported by the Dutch Ministry of Agriculture, Nature and Food Quality and the Embassy of the Netherlands in Nairobi.This document is intended to feed into discussions on further development of a complete pesticide evaluation manual for Kenya using the guidance mentioned as a starting point. Reflections on some of the methods proposed and also information on what is needed to implement the guidance developed in the project are provided. Additionally, suggestions for developing a framework for the risk assessment of aquatic organisms are given.

This document describes guidance on dossier evaluation for the registration of pest control products in Kenya. The document provides guidance for the assessment of a limited number of aspects that are part of evaluation of a pest control product registration dossier. It should therefore not be considered as a complete pesticide evaluation manual, though it is intended to contribute to a future complete pest control product evaluation manual for Kenya. The guidance should be read together with an im plementation report which contains stepping stones for further development.The guidance was developed within the Pesticide management initiative East African Region: Kenya (PEAR -Kenya) project. The project ran in the period 2016 – 2019 and was sponsored and supported by the Dutch Ministry of Agriculture, Nature and Food Quality and the Embassy of the Netherlands in Nairobi.The guidance addresses various aspects of a pest control product evaluation covering low risk pest control products, microbial pest control product, chemical pest control products and equivalence determination. The evaluation procedures developed covers a fast-track pathway for low risk products. For microbial products the procedure focusses on identification, human pathology and infectiveness and hazard and risk assessments for metabolites of potential concern. For chemical products the procedure includes methods for human health and pollinator risk assessments. The evaluation process of new pest control products can be speeded up if the active ingredient or active agent of a new product proves to be equivalent to an already registered product.

The objectives of the current study were to determine the occupational health hazards posed by the application of pesticides in rice-prawn concurrent systems of south-west Bangladesh and to assess their potential risks for the aquatic ecosystems that support the culture of freshwater prawns (Macrobrachium rosenbergii). Information on pesticide use in rice-prawn farming was collected through structured interviews with 38 farm owners held between January and May of 2012. The risks of the pesticide use to human health were assessed through structured interviews. The TOXSWA model was used to calculate pesticide exposure (peak and time-weighted average concentrations) in surface waters of rice-prawn systems for different spray drift scenarios and a simple first tier risk assessment based on threshold concentrations derived from single species toxicity tests were used to assess the ecological risk in the form of risk quotients. The PERPEST model was used to refine the ecological risks when the first tier assessment indicated a possible risk. Eleven synthetic insecticides and one fungicide (sulphur) were recorded as part of this investigation. The most commonly reported pesticide was sulphur (used by 29% of the interviewed farmers), followed by thiamethoxam, chlorantraniliprole, and phenthoate (21%). A large portion of the interviewed farmers described negative health symptoms after pesticide applications, including vomiting (51%), headache (18%) and eye irritation (12%). The results of the first tier risk assessment indicated that chlorpyrifos, cypermethrin, alpha-cypermethrin, and malathion may pose a high to moderate acute and chronic risks for invertebrates and fish in all evaluated spray drift scenarios. The higher tier assessment using the PERPEST model confirmed the high risk of cypermethrin, alpha-cypermethrin, and chlorpyrifos for insects and macro- and micro-crustaceans thus indicating that these pesticides may have severe adverse consequences for the prawn production yields.

The assessment of chemical degradation rates from water–sediment experiments like for instance OECD 308 is challenging due to parallel occurrence of processes like degradation, sorption and diffusive transport, at different rates in water and sediment or at their interface. To systematically and quantitatively analyze this limitation, we generated artificial experiment data sets using model simulations and then used these data sets in an inverse modeling exercise to estimate degradation half-lives in water and sediment (DegT50wat and DegT50sed), which then were evaluated against their true values. Results were visualized by chemical space diagrams that identified those substance property combinations for which the OECD 308 test is fundamentally inappropriate. We show that the uncertainty in estimated degradation half-lives in water increases as the process of diffusion to the sediment becomes dominant over degradation in the water. We show that in theory the uncertainty in the estimated DegT50sed is smaller than the uncertainty in the DegT50wat. The predictive value of our chemical space diagrams was validated using literature transformation rates and their uncertainties that were inferred from real water–sediment experiments.

This report describes the assessment of the current pest control products administration and management system in Rwanda. The assessment includes the aspects pesticide registration and evaluation, inspection and control and waste management. Roles, responsibilities and capacities of the public institutions involved are evaluated and current Rwandan legislations, regulations and procedures on pest control products are reviewed based on a series of consults and/or interviews with public and private institutions, actors and stakeholders in Rwanda. Finally, a set of observations and recommendations for improvement is provided based on the assessment.

Pests and diseases in fruit-orchards and lane tree-nurseries are frequently treated with pesticides, that are applied by sideways or upward spraying. To assess the risk to aquatic organisms associated with the application of these pesticides, specific scenarios are required as part of a tiered assessment scheme. In these scenarios, next to spray drift, drainage is included as well as entry route of pesticide in the ditch. This report describes the hydrological parameterisation of the edge-of-field ditch model next to fruit-orchards. This parameterised model is part of the Dutch exposure assessment scenarios for fruit-orchards. This report is an update of WEnR report 2850. In addition to the hydrological parameterisation described in WEnR report 2850, the drainage entry route to the ditch is now part of the hydrological parameterisation described.

Scenarios for future use in the pesticide registration procedure in Ethiopia were designed for 3 separate Ethiopian locations, which are aimed to be protective for the whole of Ethiopia. The scenarios estimate concentrations in surface water resulting from agricultural use of pesticides for a small stream and for two types of small ponds. Seven selected pesticides were selected since they were estimated to bear the highest risk to humans on the basis of volume of use, application rate and acute and chronic human toxicity, assuming exposure as a result of the consumption of surface water. Potential ecotoxicological risks were not considered as a selection criterion at this stage. Estimates of exposure concentrations in surface water were established using modelling software also applied in the EU registration procedure (PRZM and TOXSWA). Input variables included physico-chemical properties, and data such as crop calendars, irrigation schedules, meteorological information and detailed application data which were specifically tailored to the Ethiopian situation. The results indicate that for all the pesticides investigated the acute human risk resulting from the consumption of surface water is low to negligible, whereas agricultural use of chlorothalonil, deltamethrin, endosulfan and malathion in some crops may result in medium to high risk to aquatic species. The predicted environmental concentration estimates are based on procedures similar to procedures used at the EU level and in the USA. Addition of aquatic macrophytes as an ecotoxicological endpoint may constitute a welcome future addition to the risk assessment procedure. Implementation of the methods used for risk characterization constitutes a good step forward in the pesticide registration procedure in Ethiopia. KEYWORDS: Aquatic ecosystems; Drinking water; Ecological risk assessment; Ethiopia; Exposure modelling; Pesticides; Tropics

Any attempt to introduce more ecological realism into ecological risk assessment of chemicals faces the major challenge of integrating different aspects of the chemicals and species of concern, for example, spatial scales of emissions, chemical exposure patterns in space and time, and population dynamics and dispersal in heterogeneous landscapes. Although these aspects are not considered in current risk assessment schemes, risk assessors and managers are expressing increasing interest in learning more about both the exposure to and the effects of chemicals at landscape level. In this study, we combined the CASCADE-TOXSWA fate model, which predicts the fate of pesticides in an interconnected system of water bodies with variable hydrological characteristics, with the MASTEP mechanistic effect model, which simulates population dynamics and effects of pesticides on aquatic species at the scale of individual water bodies. To this end, we extrapolated MASTEP to the scale of realistic landscapes and linked it to dynamic exposure patterns. We explored the effects of an insecticide on the water louse Asellus aquaticus for a typical Dutch landscape covering an area of about 10 km 2 containing 137 water bodies (drainage ditches) with a total length of about 65 km and different degrees of connectivity. Pesticide treatments used in potato crop were assumed to result in a spray-drift input of 5% (non-mitigated) and 1% (mitigated) of the amount of pesticide applied into parts of the water body network. These treatments resulted in highly variable exposure patterns both in space and time. The effects of the pesticide on the species were investigated by comparing two scenarios with low and high individual-level sensitivity. We found that downstream transport of the pesticide led to exposure of water bodies that did not receive direct spray-drift input, even though this particular pesticide was assumed to dissipate rapidly from water. The observed differences in population-level effects and recovery patterns ranged from no observable effects in the low spray-drift and low sensitivity scenario to severe reduction of abundances in the high spray-drift and high sensitivity scenario. These results illustrate the sensitivity of our modelling approach, but also show the need for precise calculations of pesticide inputs and model parameterisation. Our study demonstrates the potential of coupled fate-and-effect to explore realistic scenarios at the scale of heterogeneous landscapes. Such scenarios could include the application of multiple pesticides to one or more crop types. Spatial realism of the landscape represented in the model ensures realistic consideration of population growth and dispersal as the two main recovery mechanisms. Future options for the landscape-scale fate-and-effect simulation approach include exploring the effects of mitigation measures on the risk estimates at landscape scale and hence represent a step towards risk management.