Emissions of plant protection products from glasshouses to surface water in The Netherlands

Momenteel wordt een vast percentage van 0.1% gebruikt voor de emissie van gewasbeschermingsmiddelen vanuit kassen naar het oppervlaktewater. Metingsgegevens van waterschappen wijzen erop dat de emissie van gewasbeschermingsmiddelen en biociden naar het oppervlaktewater hoger zijn dan aangenomen wordt in de toelatingsprocedure. Dit rapport onderzoekt of nieuwe benaderingen nodig zijn. De onderzoeksresultaten duiden er op dat de werkelijke emissie sterk verschilt tussen verschillende gewassen, teeltsystemen en toedieningswijzen. Dit zou in de evaluatie van de emissie meegenomen moeten worden

PEARL model for pesticide behaviour and emissions in soil-plant systems : description of the processes in FOCUS PEARL v 1.1.1

The use of pesticides in agriculture presents risks to the environment, which are increasingly evaluated by using computation models. The new PEARL model simulates the behaviour of pesticides in soil-plant systems and their emissions to the environment. The pesticide model is used in combination with the hydrological model SWAP. Various agricultural situations and ways of applying the pesticides can be simulated. The model accounts for different sorption mechanisms, in equilibrium and non-equilibriumdomains of the soil. Pesticide transport in the liquid and gas phases is described by the convection-dispersion-diffusion type equation, which is supplemented with sink terms. Comprehensive reaction schemes are processed in matrix form. The rate in first-order transformation kinetics is dependent on temperature, soil moisture content and depth in the soil. Besides computing persistence and distribution of the pesticidal compounds in soil, the model computes volatilization into the air, lateral drainage to water courses and leaching to groundwater

Need for clean water and recirculation to reduce emissions of plant protection products from soilless cultivation

Soilless cultivation suggests a closed system of water flows, the principal of which are (drip) irrigation evaporation and - in more high-tech systems -condensation water. However, in practice growers discharge water during the process of filter cleaning and also actively discharge water due to high levels of sodium or contamination with chemical or biological components. On average in the Dutch greenhouse situation 2-5% of the annual irrigated water is discharged annually. These discharges lead to pollution of surface water with nutrients as well as (residues of) plant protection products (PPPs). This awareness led in 2008 to the start of a working group that aimed to develop a risk evaluation tool for pesticide authorisation in Europe. The evaluation tool consists of a modelled approach for determining expected concentrations in surface water based on a reference scenario per crop i.e., a description of an actual situation including the technical layout of the glasshouse, the climatological year and the receiving ditch For two currently registered PPPs that are used in spray applications, the annual emission to surface water was calculated using different scenarios. As scenarios, substrate-based rose production and pot plant production were selected in combination with water sources of variable sodium concentrations that commonly occur and are used in The Netherlands. Sodium was found to be the only quantifiable argument for growers for active discharge, and therefore it was used as a leading principle for discharge in the water flow model. Water discharge was found to range from 80 to 700 m3 ha 1 year-1, leading to nitrogen emissions of 17 to 149 kg N ha∗ year-1. The emission of PPPs in these scenarios amounted to 0.02-3% of the total active substance that was applied.</p

Emissieroutes van gewasbeschermingsmiddelen in de teelt van snijmaos in het zuidoosten van Noord-Brabant; interpretatie van meetgegevens uit het demonstratieproject 'Bewust boeren voor een schone Maas' in 1997

Voor het demonstratieproject `Bewust boeren voor een schone Maas' is gedurende 1997 een uitgebreid chemisch meetprogramma uitgevoerd bij drie snijmaospercelen in de omgeving van Someren (Noord-Brabant). Het programma had ten doel informatie te verkrijgen omtrent de belangrijkste emissieroutes van gewasbeschermingsmiddelen naar oppervlaktewater in de snijmaos. Voor de drie bestudeerde stoffen (metolachloor, atrazin en bromoxynil) speelden naast spuitdrift ook oppervlakkige afspoeling en transport via verwaaiing van gronddeeltjes een belangrijke rol bij de belasting van oppervlaktewater. Aanbevolen wordt om meer aandacht te besteden aan deze routes in het onderzoek en bij het ontwikkelen van beleid gericht op emissiereductie

Nadere afstemming van het gebruik van de instrumenten Bestrijdingsmiddelenatlas en Natuur Milieu Indicator in het licht van de Evaluatie Duurzame Gewasbescherming 2006.

Environmental Biology - ol

Pesticide leaching to the groundwater in drinking water abstraction areas; analysis with the GeoPEARL model

In the new Dutch decision tree for the evaluation of pesticide leaching from soils, leaching to the shallow groundwater is assessed with the spatially distributed model GeoPEARL. The relative vulnerability of the groundwater in the drinking water abstraction areas is estimated. The general conclusion is that the groundwater within the drinking water abstraction areas as a whole is up to five times more vulnerable to pesticide leaching than the groundwater in Dutch agriculture. The higher vulnerability of the groundwater in the drinking water abstraction areas is primarily caused by lower soil organic matter contents

Dutch Environmental Risk Indicator for Plant Protection Products

The NMI 3 focusses on indicators for emissions to surface water and the related aquatic risk resulting from agricultural use of pesticides in the Netherlands. The risk indicator is the exposure toxicity ratio. The model also considers the risk to groundwater, soil organisms and the terrestrial ecosystem. The model calculates indicators for emission to surface water resulting from atmospheric deposition, spray drift, drainage flow, point sources, discharge from greenhouses. The model combines a wide range of information about pesticide sales, usage, spray drift mitigation, emission factors, crop maps, surface water, soil, climate, and substance properties. The primary goal is to compare on a relative scale the annual risk at national scale at the starting and end year of the policy period. The results can be used for ranking, for comparing applications of similar type and for visualisation of spatial patterns of indicators. The result cannot be translated into a risk at a specific location and time

Guidance proposal for using available DegT50 values for estimation of degradation rates of plant protection products in Dutch surface water and sediment

The degradation rate of plant protection products and their transformation products in surface water and sediment may influence their concentrations in Dutch surface water. Therefore the estimation of these rates may be an important part of the assessment of the exposure of aquatic organisms. We propose a stepped sequence of studies for estimating the rate in water going from simple and conservative to more sophisticated and more realistic studies. The sequence includes: - studies on hydrolysis and photolysis; - studies with fresh surface water in the dark; - water-sediment studies in the dark or in light; - studies with algae and macrophytes; - outdoor studies in realistic surface water systems. The usefulness of these studies for the exposure assessment in Dutch surface water is discussed