Insecticide contamination of the River Meuse in August 2007. Risk Assessment on the basis of MAM calculations

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Reinaldo Penailillo B. Yenory Morales Erwin Meijers

Insecticide contamination of the

River Meuse in August 2007

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Prepared for: Delft Cluster Bureau

Insecticide contamination of the

River Meuse in August 2007

Risk Assessment on the basis of MAM calculations

Reinaldo Penailillo B. Yenory Morales Erwin Meijers Report November 2008

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Client Delft Cluster Bureau

Title Insecticide contamination of the River Meuse in August 2007

Abstract

On 31 July the company Chimac-Agriphar from Ougrée discharged 64 kilo chlorpyrifos and 12 kilo cypermethrin into the River Meuse, imposing risks to recreation (swimming and fishing), ecology (about 20 to 25 ton fish were killed) and drinking water production. In this study a retrospective risk analysis of this accidental spill was done in order to get more understanding of the risks on fish and drinking water production. The exposure is characterized through environmental concentrations of cypermethrin and chlorpyrifos estimated with the Meuse Alarm Model (MAM) at relevant locations in the Netherlands. Following acute toxicity (LC50), we calculated PAF of Atlantic salmon, brown trout and fish community with peak concentrations and 96 hour average concentration, while in the case of chronic toxicity (NOEC) PAF were calculated with 96 hour and 96x10 hour average concentrations.

The results showed that the concentration (peak or average) adds uncertainties to the estimation of toxicity, especially when the concentrations are low (e.g. cypermethrin). For acute toxicity, when 96 hour average concentrations of cypermethrin were used, fish was not potentially affected, while with peak concentrations PAF reached values up to 37%. In the case of chlorpyrifos, PAF values were above 5% and up to 20% when peak concentrations were used and up to 10% with 96 hour average concentrations. For chronic toxicity, Atlantic salmon appeared to be seriously affected by cypermethrin (lower PAF 38%). The results for fish community showed a PAF above 5% at most of the locations. It can be concluded that the accidental spill of chlorpyrifos in July 2007 imposed a serious risk to the fish community on the short term (2-3 days) but less of a risk on the long term (40 days). The spill of cypermethrin imposed a serious risk in particular to Atlantic salmon on the long term, as a lower to medium risk to the fish community.

With respect to drinking water production, the exceedance of the standards may lead to stops of the water intake: more than 3 days long at Heel and more than 6 days long at Keizersveer.

References Accidental spill, Meuse, August 2007, chlorpyrifos, cypermethrin, risk

characterization, toxicological effects, drinking water production

Ver Author Date Remarks Review Approved by

1 Reinaldo Peñailillo May 2008

2 Reinaldo Peñailillo November 2008 A.J. Wijdeveld A.G. Segeren

Project number Q4489.40

Keywords

Number of pages 47

Classification None

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Acknowledgements

The authors want to thank Gerard van Vliet, Manager of the Department Crisis Management and Information Services, Direction Water and Use, Waterdienst, for allowing us to use measurement data for this study. We also thank Bert van Munter for the search and deliver the measurement data. The authors thank Arjan Wijdeveld (Deltares) and Gerard van den Berg (KIWA) for their comments on earlier versions of the report. This work has been financed by the Delft Cluster Programme.

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1 Introduction

1.1 Contamination of the Meuse with insecticides

On 31 July the company Chimac-Agriphar from Ougrée (Seraing) discharged about 64 kilo chlorpyrifos and 12 kilo cypermethrin in the River Meuse (press releases VMM, BBLV).

The discharge was the same day 31 July noticed by the Waalse environment police and reported to the Flemish Environment Agency (VMM). The company self notified days later to the Waalse environment police. On 3 August the government of Wallonia called for swimming and fishing prohibition. The same day, the news about the cause of the pollution came public and the importance of this calamity appeared. In Flanders it was advised to not consume fish and wait for the first results of the measurements. In the Netherlands there was a negative advice for fishing and swimming.

The contamination with these pesticides killed at the beginning of August thousands fish in the River Meuse (see Figure 1.1). According to the Flemish Environmetnt Agency (VMM) about 20 to 25 ton fish were killed. The Bond Beter Leefmilieu Vlaanderen (BBLV) mentioned an estimation of 25.000 fish killed. The dead of other water fauna was not estimated but it was considered without doubts distinguished.

Not only fish and other water species were of concern but also the human health. In the Netherlands there are many inhabitants who depend on the Meuse water as source for drinking water. Also in the Antwerp region Meuse water is used ultimately for drinking water production (through the Albert canal). The 8.8 million inhabitants of the Meuse basin consume drinking water produced in de district from ground- and surface water. Chlorpyrifos is an organophosphate insecticide used in agriculture for controlling cutworms, corn rootworms, cockroaches, grubs, flea beetles, flies, termites, fire ants, and lice (EXTOXNET, 1996a). The crops with the most intense chlorpyrifos use are cotton, corn, almonds, and fruit trees including oranges and apples (NASS, 2008). Important to mention is that chlorpyrifos is one of the priority substances under the Water Framework Directive.

Cypermethrin was initially synthesized in 1974 and first marketed in 1977 as a highly active synthetic pyrethroid insecticide, affective against a wide range of pests in agriculture, public health, and animal husbandry (EXTOXNET, 1996b). Chemically, cypermethrin is the racemic mixture of eight isomers, four cis- and four trans-isomers.

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As result of this calamity, the system elements on which the stressors cypermethrin and chlorpyrifos may have had an effect are summarized in Table 1.1.

Table 1.1 Ecosystem element or system function on which the stressors may have had an effect and

their risks

Ecosystem element or system function Risk

Reduction in species richness or abundance Fish

Increase mortality

Reduction in species richness or abundance or increase bioaccumulation effect

Benthic macroinvertebrates

Increase mortality

Reduction in species richness or abundance or increase bioaccumulation effect

Aquatic insects

Increase mortality

Algae Reduction in species richness or abundance

Drinking water production Deterioration of water quality for drinking _{water production proposes} Fishing

Swimming

Deterioration of water quality for recreation proposes

1.2 Research aims

The aim of this study is to get more insight in the accidental spill of cypermethrin and chlorpyrifos of July 2007 in the River Meuse through an retrospective risk analysis and the use of the Meuse Alarm Model (MAM). We focus on the ecological effects and on the main functions of the systems in the Dutch part of the River Meuse (downstream of Eijsden).

In particular we give special attention to the following main research questions:

• What were the relevant ecosystems (or biological elements according the Water Framework Directive) and the system functions at risk during the calamity of July 2007?

• Can adequate assessment endpoints be defined for assessing a calamity in the River Meuse?

• Can the MAM be used to estimate the environment concentrations of cypermethrin and chlorpyrifos and their temporal distribution (duration, frequency and timing) at both relevant location for ecology and for the system functions? • Can the risk on the ecosystem and the system functions be estimated by

integrating simulated environmental concentrations and effects data?

• What are the uncertainties of the risks estimated in this study and how can they be evaluated?

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1.3 The Meuse basin

The Meuse is an important river in Northwest Europe. The Meuse basin of about 34.500 km² covers 6 States: France, Luxemburg, Belgium (Walloon Region and Flemish Region), The Netherlands and Germany (see Figure 1.2).

In Table 1.2 the relevant characteristics of the International River Basin District (IRBD) Meuse are presented. The IRBD Meuse can be defined as the river basin of the Meuse. It encompasses the surface waters (rivers, lakes), the groundwater and the coastal waters associated with it. The IRBD Meuse covers, upstream to downstream, parts of the territories of France, Luxembourg, Belgium, Germany and The Netherlands. In other words, every drop of water reaching the surface of the IRBD ultimately reaches the North Sea via the River Meuse.

Table 1.2 Relevant characteristics of the International River Basin District (IRBD) Meuse (ICM, 2007)

Fresh water Groundwater

Surface (km²) Population (x 1000) Amount of water bodies ‘lakes’ Amount of water bodies ‘rivers’ Line path rivers (km) Amount water bodies Average surface of water bodies France 8919 671 5 149 3298 12 903 Luxemburg 6543 43 0 3 15 1* 85 B-Wallonië 12300 2189 12 245 4934 21 592 B-Vlaanderen 1596 411 3 17 269 10 350 The Netherlands 700 3500 127 188 5614 5 2449 Germany 3968 1994 1 198 1471 32 125 TOTAL 34548 8808 150 840 15936 82

* The groundwater body of is connected to the ICD Rhine who manages it.

The source of the main river, the Meuse, is situated at an altitude of 384m in Pouilly-en-Bassigny in France. Its length, from its source to its mouth in the North Sea, is 905 km. The most important sub-basins in the IRBD Meuse are those of the following tributaries: the Chiers, the Semois, the Lesse, the Sambre, the Ourthe, the Rur, the Schwalm, the Niers, the Dommel and the Mark. Several of these sub-basins are trans-boundary. The water in the IRBD Meuse has many functions, of which the most important are (ICM, 2005):

• Supply of drinking water • Domestic uses

• Agriculture

• Industrial use (incl. hydro-electric)

• Navigation (transportation of goods, and leisure) • Recreation

• Living ecosystem

• Element of the landscape

The 8.8 million inhabitants of the IRBD Meuse consume drinking water produced from ground- and surface water in the district. Moreover, substantial quantities of water are exported by pipes or canals to provide drinking water to about 6 million people living outside the IRBD Meuse. The cities Brussels, Antwerp, the Hague and Rotterdam depend in a main part on the Meuse water for their drinking water facilities

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1.4 Approach method

In this study, we considered the risk assessment of the insecticide incident in the River Meuse of July 2007 as a process that evaluates the likelihood that adverse effects on the ecosystem (ecological effects) and/or the functions of the system (functional effects) occurred as a result of past exposure to cypermethrin and chlorpyrifos (retrospective risk assessment). The framework used in this study is adapted from the Guidelines for Ecological Risk Assessment (USEPA, 1998) and presented in Figure 1.3.

Figure 1.3 Risk assessment framework (after USEPA, 1998)

Firstly, we formulated the problem by generating and evaluating preliminary hypotheses about why ecological and functional effects have occurred from the accidental spill. The problem formulation resulted in two main products:

• Assessment endpoints, which are explicit expressions of the actual environmental value that is to be protected, operationally defined by an ecological entity or system function and its attributes. Three principal criteria were used to select assessment endpoints: i) relevance; ii) susceptibility to known or potential stressor; and iii) relevance to management goals.

• Conceptual models, which describe the relationships among stressor, exposure, and assessment endpoint response, along with the relation for their selection (risk hypotheses), and present visual representation of the risk hypotheses to describe the important pathways (diagrams).

Assessment Endpoints

Conceptual Models

PROBLEM FORMULATION

Exposure Characterization Effect Characterization ANALYSIS PHASE

Environmental Concentrations (EC)

Toxicological Endpoints Concentrations

Water Quality Standards

Exposure

Profile Profile Effect

RISK CHARACTERIZATION

Ecological/Functional risk description Ecological/Functional risk estimation

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Secondly, we examined the exposure and effects, and their relationships between each other and the system characteristics (analysis phase). Through this analysis we provided an answer to what ecological entities and system functions are affected. Also we identified the nature and the intensity of the effects on the selected entities and functions after the accidental spill. The products of this phase were:

• Exposure profile that identifies the receptor or exposed ecological entity, describes the course a stressor takes from the source to the receptor (i.e., the exposure pathway), and the intensity (amount of chemical per day) and spatial and temporal (duration, frequency and timing) extent of co-occurrence or contact. In this study we quantified the contact as environmental concentrations (EC), with the assumption that the chemical was well mixed and that the organism moved randomly through the water system.

• Effect profile that describes the effects elicited by the stressor (insecticides), links them to the assessment endpoints, and evaluates how they change with varying stressor levels.

▪ In the ecological assessment we used toxicological endpoint concentrations (e.g. LC50 or NOEC). The shape of the stressor-response curve was needed to determine the presence or absence of an effects threshold. Levels of median effects (or effects elicited in 50% of the test organisms exposed to a stressor) were selected because the level of uncertainty was minimized at midpoint of the regression curve and were used for preliminary assessments and comparative purposes. Because these test sedom exceed 96 hours, their main value lies in evaluating short-term (acute) effects of chemicals. For chronic toxicity we used the No-observed-adverse-effect level NOAEC. ▪ In the assessment of effects on system functions we used water quality

standards (e.g. drinking water standards or environmental quality objectives).

Finally, we characterized the risk to conclude the occurrence of exposure and the adversity of existing effects. The estimation of the risk was done by integrating exposure and effects data and evaluating any associated uncertainty. For the ecological risk characterization we used the Inverse Method of Straalen or the Potentially Affected Fraction (PAF) – method (Van den Ende, 2006). The ecological risk characterization was considered as a general assessment since we used data that were general for each of the pollutants, but that may divergent for a specific location. Since only for a certain amount of species NOEC/LC50 values are known, it is assumed that for the NOEC/LC50 values the distribution of all species can be characterized through a log-normal probability distribution. With this cumulative distribution it is possible to calculate based on the concentration of a substance in the water the fraction or percentage of the amount of species that may experience potential effects. For the function risk characterization we compared the EC directly with the water quality standards. When the standards were exceeded we expected an adverse effect on the system function. The risk characterization finalized with an interpretation of the significance of the adverse effects on the assessment endpoints. Changes in the assessment endpoints are considered adverse when they alter valued structural or functional attributes of the entities under consideration.

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2 Problem

Formulation

In the problem formulation, the preliminary hypothesis about system functional and ecological effects that have occurred from the accidental spill with insecticides chlorpyrifos and cypermethrin in the River Meuse were generated and evaluated. This chapter starts with a description of the relevant element of the ecosystem and system functions that were at risk. The problem formulation results in the following products: (1) assessment endpoints that adequately reflect management goals and the Meuse ecosystem, (2) conceptual models that describe key relationships between chlorpyrifos/cypermethrin and assessment endpoints.

2.1 Ecological elements and system functions at risk 2.1.1 Ecological elements at risk

The Water Framework Directive (WFD) prescribes that before 2015 a good chemical status and a good ecological status have to be achieved for the fresh water. For that purpose fresh waters have to be monitored and evaluated based on the level for which the WFD objectives are defined.

The WFD is explicit in the selection of biotic elements for the categories of water bodies and in the parameters to be determined for the analysis and the assessment of the biological quality elements (ECOSTAT, 2003). The biological elements for rivers are: • Composition and abundance of aquatic flora. Phytoplankton is not explicitly

included in the list of quality elements for rivers in Annex V of the WFD, but is included as a biological element. It should therefore be possible to use phytoplankton as a separate element, if needed and appropriate (especially in low land large rivers). The other aquatic flora specifically referred to in the normative definitions for rivers are macrophytes and phytobenthos.

• Composition and abundance of benthic invertebrate fauna • Composition, abundance and age structure of fish fauna

The International River Basin District (IRBD) Meuse has made a classification of the water bodies on the basis of the hydro geographic areas, the substrates to which this areas drain and the size of the river basins. According to these data the States have defined their status and tendency monitoring programme of the status of the surface water. In the Report about the Coordination and Status and Tendency Monitoring Programme in the IRBD Meuse (IRBD Meuse, 2007) a choice is been done with respect to the biological quality elements for the Meuse basin.

• Macrophytes were not taken into account because some parties (State or Regions) did not measure them (or less frequent in comparison with other States). This biological element was therefore defined less relevant.

• The element phytoplankton is considered in the large water courses relevant, main stream Meuse starting from Bar in France.

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• The element fish is judge on the basis of a diagnosis of the biocoenosis or system community of the fish. The migratory fish indicated as important water management questions for the IRBD Meuse and receives a special attention in the international coordination. The national/regional methods for assess the status of the fish populations do not accept the evaluation for migratory fish. Therefore, migratory fish is defined a special extra biological quality element. The problems of free fish migration which connects with this migratory fish problem form a component of the hydromorphology status. For the migratory fish different programs of research are started regarding measures and efficiency. For the coordination of the status and the tendency monitoring of the status of the large migratory fish populations (salmon, sea trout and eel) is it possible through the monitoring of the upstream and downstream migration at a number of wears to evaluate the status of the populations in the catchment (e.g. Meuse at Lixhe). According to International Commision Meuse ICM (2000) special attention is given to the problems and actions with respect to the Atlantic salmon and brown trout (or sea trout). However, these are not the only species of migratory fish in the River Meuse (see Table 2.1).

Table 2.1 Migratory fish species (Latin names) in the River Meuse (ICM, 2000). Diadromus refers to

migratory behaviour of fish migrating between salt and fresh waters

Latin name Salmo salar Salmo trutta trutta Anguilla anguilla Alosa alosa Alosa fallax Coregonus oxyrhynchus Acipenser sturio Petromyzon marinus Lampetra fluviatilus Platichthys flesus

Diadromus migratory fish

Osmerus eperlanus Chondrostoma nasus Barbus barbus Leuciscus idus Leuciscus cephalus Leuciscus leuciscus Thymallus thymallus

Fresh water migratory fish

Salmo trutta fario

In the report Migratory fish in the Meuse: State of affairs (ICM, 2000) an estimation of the possible future salmon pile in the river basin of the Meuse was done. In the Netherlands there are a few (potential) suitable spawning and growing areas for the Atlantic salmon and the brown trout. The most important locations in the river catchment of the Meuse are the Swalm, the Roer, the Grensmaas and the Geul.

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Table 2.2 Amount of catch specimens brown trout and Atlantic salmon in the Meuse in the Netherlands (ICM, 2000)

Location – year Brown trout Atlantic salmon

Downstream weir Borgharen, 1983-1986 2

Grensmaas Borgharen – Linne, 1992 - -

New trap weir Linne, 1990 8 -

Downstream weir Roermond, 1993 - -

New trap weir Roermond, 1994 2 -

Downstream weir + trap Belfeld, 1988-93 23 -

Downstream weir Lith, 1993 6 -

New trap + fyke Lith, 1993 90 6*

Weir Lith, 1994 59 6*

* Exclusively adult salmons 2.1.2 System functions at risk

Occasional discharges as result of calamities, like accidental spills of chemical substances, consist of onetime discharges that could not be anticipated. The influence of occasional discharges on water quality is eminent, but is in most cases, especially on the system functions, temporally. In the worst cases, especially regarding the ecosystem, the effects can be chronic. According to the press releases in August 2007, the water functions of the River Meuse that were affected by the discharge of cypermethrin and chlorpyrifos were mainly drinking water production and recreation (fishing and swimming).

The Meuse together with the Rhine is the most important rivers for the Dutch drinking water facilities. The Meuse River covers about 20% of the total drinking water needs (Volz et al., 2004). Not only in Rotterdam and den Haag, but also in places as Cadzand, Noordwijk and Helden treated Meuse water comes from the tap. Next to this, Brussels and Antwerp also use the Meuse water for drinking water production, even though these cities are located in the basin of the Scheldt. Therefore, the drinking water function of the Meuse defines high standards for de water quality than other function of this river as navigation, recreation or nature.

An occasional discharge may cause in practice temporal water capture stop of a water company. The risk of interrupt of a water capture, during a short or long period, depends on the one hand on the presence of (potentially) contaminant activities and the frequency when contamination occurs and on the other hand on the nature of the water capture point (i.e. hydrological and physical circumstances that may cause reduction due to dilution and that are important for the available reaction time) (Wuijts et al., 2007). This defines the effect of the contamination as the interruption of the water capture, eventually followed by reduction of drinking water delivery or risks for the human health.

Drinking water standards

In the Netherlands, the drinking water standards for surface water through application of simple treatment are defined from the standard of the Water Company Resolution (in Dutch Waterleidingbesluit) and the yield of the simple treatment. For chlorpyrifos, the drinking water standard from the Waterleidingbesluit is 0.1 µg/l, which is the same than the WFD standard for fresh water. For all pesticides and their relevant metabolites (excluding AMPA and BAM) the drinking water standard is 0.1 µg/l

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According to Kegley et al. (2007), for drinking water the 1-day exposure value for chlorpyrifos in the US should be no more than 30 µg/l, and the lifetime exposure no more than 20 µg/l.

Environment Quality Objectives (EQO)

In the Netherlands, the present ecologic standards (Environment Quality Objectives EQO) are set in the Official bulletin (in Dutch Staatscourant) of 22 December 2004 (VROM, 2004). This regulation concerns pollution that is discharged in the aquatic environment of the Social Community. For chlorpyrifos in the EQO 3 ng/l. For cypermethrin there is no EQO defined. However, in the Fourth National Policy Document on Water Management (in Dutch de Vierde Nota Waterhuishouding NW4), old regulation for assessing the quality of fresh water, sediments and groundwater, the Maximum Allowed Concentration (MAC) for cypermethrin was set on 0.1 ng/l (http://www.waterland.net/nw4/Nederlands/wk-9-bij/index.html). Table 2.3 summarizes the standards for cypermethrin and chlorpyrifos. Important to notice is that the EQO’s are a factor 1000 lower than the drinking water standards.

Table 2.3 Standards for cypermethrin and chlorpyrifos in freshwater

MAC dissolved (ng/l) Objective Concentration (ng/l) EQO or MAC (ng/l) Drinking water standards (ng/l) cypermethrin 0.09 0.001 0.1 100 chlorpyrifos 3 0.03 3 100 2.2 Assessment endpoints

The following table present a short evaluation of the possible ecological assessment endpoints with regard to the ecological relevance, susceptibility to know stressors and relevance to management goals. This evaluation is based on the information presented in the previous paragraph.

All possible ecological assessment endpoints have an ecological relevance and may be susceptible to chlorpyrifos and cypermethrin. Even when phytoplankton, macrophytes and fish are mentioned within relevant biological quality elements for the WFD, fish and especially migratory fish are indicated as very important water management ecological entities for the IRBD Meuse and receive a special attention in the international coordination. Macrophytes are not measured by all States within the IRBD Meuse and phytoplankton is important in the main stream. In this study we focus on the survival of the fish community and migratory fish Atlantic salmon and brown trout.

As mentioned in section 2.1, the functions of the Meuse system that were at risk were mainly drinking water production and recreation. We decided to focus on the function drinking water because the drinking water function of the Meuse defines high standards for the water quality than other function. With the focus on this function we selected as assessment endpoints the exceedance of standard for drinking water production.

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Table 2.4 Possible assessment endpoints (Ecological) Relevance Susceptibility to known stressors Relevance to management goals Survival of

Macrophytes Yes Yes

Macrophytes not measured by all

States Survival of

Phytoplankton Yes Yes

Phytoplankton only of importance in the

main stream Survival of Fish

community Yes Yes High

Survival of

Migratory Fish Yes Yes Very high

Exceedance of drinking water standard

Yes Yes Very High

Exceedance of

EQO Yes Yes High

2.3 Conceptual models

2.3.1 Risk Hypothesis

The risk hypothesis in this section presented refer to i) the transport, distribution and transformation of the insecticides cypermethrin and chlorpyrifos; ii) ecological effects, and iii) human health effects.

Environmental transport, distribution and transformation

As mention before, occasional discharges of chemicals as result of calamities consist of onetime discharges that could not be anticipated. Water quality processes during occasional discharges that are relevant from the point of view of drinking water production are dilution (in x, y and z direction) with reduction of the peak concentration as result, delay as result of the stagnation zones (e.g. groyne fields) and decay for not conservative substances and/or organisms (Wuijts et al., 2007). The influence is determined by:

• the distance from the spill point until the withdrawn point • the stream conditions between discharge and withdrawn point • type and amount of discharged substance

• the sediment as a source/sink

• possible presence of any toxic intermediates in the break down path (e.g. dichlorvinyl)

• the level and velocity of communication exchange between the company responsible, the water managers and the water company

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• the time needed for measurement, analysis and reaction

The next paragraphs give attention to the transport and transformation processes particularly for cypermethrin and chlorpyrifos.

a) Cypermethrin

Cypermethrin is one of the more light-stable pyrethroids with very limited degree of photodegradation (IPCS, 1989). According to the Extension Toxicology Network EXTOXNET (1996b), under normal environmental temperatures and pH, cypermethrin is stable to photodegradation with a half-life of greater than 100 days. The International Program on Chemical Safety IPCS (1989) mentions a study on the effects of sunlight on dilute aqueous acetonitrile solutions of cypermethrin irradiated in sunlight for 32 days. At the end of the study 89.4% of the cypermethrin remained. According to IPCS (1989) the most important photodegradation products are 2,2-dimethyl-3-(2,2-dichlorovinyl) cyclopropane-carboxylic acid (CPA), 3-phenoxybenzoic acid (PBA) and, to some extent, the amide of the intact ester. These products do not differ greatly from those resulting from biological degradation.

In neutral or acid aqueous solution, cypermethrin hydrolyzes slowly, with hydrolysis being more rapid at pH 9 (basic solution). Under normal environmental temperatures and pH, cypermethrin is stable to hydrolysis with a half-life of greater than 50 days (EXTOXNET, 1996b). According to IPCS (1996), in a study at 25°C, at acid pH values, the half-life of the isomers was one or more years, but it was appreciably shorter at pH 7, 3 weeks at pH of about 8 (in natural waters, sterilized by filtration) and had fallen to a matter of minutes at pH 11. In an another study of the fate of cypermethrin under biotic conditions, simulating those of rivers and ponds, degradation was rapid in all cases (at 16°C). Some 50% of the cypermethrin was lost in less than 2 weeks and 90% within 2-9 weeks (IPCS, 1996).

Microbial degradation may also occur (EXTOXNET, 1996b), however no further information was found.

b) Chlorpyrifos

Chlorpyrifos is moderately persistent in soils, with a half-life usually between 60 and 120 days, but that can range from 2 weeks to over 1 year, depending on the soil type, pH, climate, and other conditions. The concentration and persistence of chlorpyrifos in water depends on the type of formulation. Emulsifiable concentrations and wettable powders produce a quicker increase in concentration than granules and controlled release formulations. However, the former declines rapidly due to adsorption to sediment and suspended matter, while the later persists longer (EXTOXNET, 1996a) Volatilization is probably the primary route of loss of chlorpyrifos from water. Volatility lives of 3.5 and 20 days have been estimated for pond water. The photolysis half-life of chlorpyrifos is in to order of 3 to 4 weeks. The rate of hydrolysis is constant in acidic to neutral waters, but increases in alkaline waters. In water at pH 7.0 and 25 C, it has a half-life of 35 to 78 days. Hydrolysis rate increases with temperature, decreasing by 2.5- to 3-fold with each 10 C drop in temperature (EXTOXNET, 1996a and references there in).

Ecological effects

a) Cypermethrin

Freshwater fish are also highly susceptible to the toxic effects of cypermethrin. According to Cole et al. (2002) the majority of acute effect concentrations ranging from

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0.05-1.2 µg/l. The lowest reported fish acute LC50 is 0.006 µg l-1 reported for mosquito fish (Gambusia affinis) following 96 hours exposure (Cole et al., 2002), in rainbow trout is 0.0082 mg/L, and in bluegill sunfish is 0.0018 mg/L (EXTOXNET, 1996b).

Cypermethrin is metabolized and eliminated significantly more slowly by fish than by mammals or birds, which may explain this compound's higher toxicity in fish compared to other organisms. The half-lives for elimination of several pyrethroids by trout are all greater than 48 hours. EXTOXNET (1996b) reported a bioconcentration factor for cypermethrin in rainbow trout was 1200 times the ambient water concentration, indicating that there is a moderate potential to accumulate in aquatic organisms.

Cypermethrin is very toxic for fish in clear water under laboratory conditions. The data presented in IPSC (1996) demonstrate a similar high acute toxicity for both cold- and warm-water species of fish. According to this author, there is no evidence of a significant effect of temperature on toxicity of cypermethrin, neither of the hardness or pH of water.

In the Environmental Health Criteria 82: Cypermethrin (IPSC, 1996) a study is presented to emphasize the relevance of the high degree of adsorption of cypermethrin on suspended solids can reduce (about 40%). According to this study, the presence of suspended solids decreases the toxicity for rainbow trout by at least a factor of 2. In IPSC (1996) a study is presented where the effects of cypermethrin on the most sensitive stage in the life cycle (long-term effects) of the Feathed minno (Pimephales promelas) were investigated. On the basis of the most sensitive parameter, i.e., survival of young fry, the no-observed-adverse-effect level (NOEC) of cypermethrin lay between 0.03 and 0.12 µg/litre.

b) Chlorpyrifos

Chlorpyrifos toxicity to fish is related to water temperature, pH and hardness. Turner (2003) compiles information about acute (96-H LC50) and chronic toxicity of chlorpyrifos for 40 species of fish. In summary, the pollutant is categorized as very highly toxic to most species with acute toxic concentrations as low as 0.0008 mg/L for bluegill sunfish, and between 0.005 mg/L and 0.026 mg/L for salmonids. EXTOXNET (1996) reports 96-hour LC50 values of 0.009 mg/L in mature rainbow trout, 0.098 mg/L in lake trout, 0.806 mg/L in goldfish, 0.01 mg/L in bluegill, and 0.331 mg/L in fathead minnow. In laboratory experiments with juvenile Atlantic salmon (Salmo salar), behavioural changes were observed when exposing the fish to 0.10 mg/L during 24 h, and mortality occurred at 0.25 mg/L (Peterson, 1976).

In an experiment with fathead minnows exposed to chlorpyrifos for a 200-day period during which they reproduced, the first generation of offspring had decreased survival and growth (EXTOXNET, 1996). For both parents and offspring, effects on growth were observed at 0.00012 mg/L, and survival was affected at 0.001 mg/L. For early life stages, reduced growth and survival as well as increase occurrence of spinal deformity were observed at concentrations between 0.002 mg/L and 0.0048 mg/L (Turner, 2003). In the literature review made by Turner (2003), the lowest no-observed-effect concentration (NOEC) reported for fish is 0.0057 mg/L, for the fathead minnow (Pimephales promelas), and for aquatic invertebrate is 0.0004 mg/L, for water flea (Daphnia magna).

Chlorpyrifos accumulates in the tissues of aquatic organisms. Studies involving continuous exposure of fish during the embryonic through fry stages have shown bioconcentration values of 58 to 5100 (EXTOXNET, 1996).

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Human health effects

a) Cypermethrin

In humans, urinary excretion of cypermethrin metabolites was complete 48 hours after the last of five doses of 1.5 mg/kg/day (EXTOXNET, 1996b). The US EPA has classified cypermethrin as a possible human carcinogen (group C) because there is limited evidence that it causes cancer in animals.

b) Chlorpyrifos

Chlorpyrifos is a neurotoxin and suspected endocrine disruptor. It has been classified as moderately toxic by the US Environmental Protection Agency.

In humans, chlorpyrifos and its principal metabolites are eliminated rapidly. After a single oral dose, the half-life of chlorpyrifos in the blood appears to be about 1 day. It does not appear to have a significant bioaccumulation potential. Following intake, a portion is stored in fat tissues but it is eliminated with a half-life of about 62 hours (EXTOXNET, 1996a, and references there in).

2.3.2 Diagrams

Figure 2.1 Important pathways (emission-fate-exposure) for chlorpyrifos and cypermethrin. The process

volatilization is mainly relevant for chlorpyrifos

EMISSION EXPOSURE FATE Chimac-Agriphar WATER CHLORPYRIFOS / CYPERMETHRIN photodegradation Suspended particulate matter sorption sedimentation resuspension SEDIMENTS uptake direct contact Drinking water FISH HUMANS hidrolisis (Volatilization)

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3 Analysis

phase

In this chapter, the two primary components of risk, exposure and effects, and their relationships between each other and the Meuse system characteristics were analyzed. The objective of the analysis phase was to provide the required information for determining ecological or function responses to the stressors cypermethrin and chlorpyrifos under exposure conditions of interest.

3.1 Characterization of exposure

3.1.1 Exposure characterization with the Meuse Alarm Model (MAM)

The Meuse Alarm Model (MAM) developed by Deltares was applied in the present study for the estimation of the Environmental Expected Concentrations (EEC) of cypermethrin and chlorpyrifos. The MAM provides an easy and rapid assessment of the effect of accidental spills in a Meuse basin and its main tributaries. The model predicts the expected travel time and concentration levels of the cloud of pollutants, at selected locations and times in the river basin.

The computations by the model proceed in two steps: (1) computation of river discharges and velocities (to compute travel times to selected locations), and (2) computation of concentrations. Step (1) is based on a reach-by-reach computation of the river discharge and the stream flow velocity. Input data are the observed water levels in selected gauge stations (and in some cases the discharge itself, in regulated river stretches). The model uses rating curves (Q,h-tables) and tabulated cross-section data to perform the computation. This means that only stationary discharges can be calculated. Step (2) is based on an analytical solution to the governing advection-diffusion-equation. The MAM has the option of including decay for not conservative substances through the definition of only one decay rate. This is very important in the simulation of the fate of cypermethrin and chlorpyrifos for the processes of hydrolysis, photodegradation or volatilization. The MAM also includes delay as result of the stagnation zones (or dead zones). However, the MAM does not include processes, such as sorption to suspended matter which is very important for the simulation of the fate of insecticides. The mathematical formulation of the model is for the largest part identical to the one used for the Rhine Alarm Model (WL | Delft Hydraulics, 2000). The travel time of a given pollutant is estimated through the flow velocities which are coupled to the mass balance. The following parameters influence the travel time (see Figure 3.1):

• a longitudinal dispersion coefficient (α); • the presence of dead zones (β); and • a lateral dispersion coefficient (γ).

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Figure 3.1 Parameters influencing the travel time in the MAM

3.1.2 Input for the MAM

Spill characteristics

For the simulation, the date of the spill is 31 July 2007 at 12:00. The location of the discharge is close to Liege at the Belgian branch of the Meuse River, kilometre 110. The spill is considered as an instantaneous discharge.

Discharges and water levels

Discharge or water level data are used for the following gauge stations: Chooz, Gendron, Angleur, Lixhe (Vise), Sint Pieter, Salzinnes, Smeermaas, Loozen, Borgharen dorp, Megen, Bunde, Maaseik and Venlo. The simulation period for which the data is required is from 31 July until 31 August.

Data were obtained from the Rijkswaterstaat Infocentrum Binnenwateren (www.infocentrum-binnenwateren.nl) for all stations with the exception of Maaseik and Venlo. Figure 3.2 presents the available discharges at Infocentrum. For the stations Maaseik and Venlo, the data were obtained from the database of FEWS-NL. Discharges were available for Venlo, and water levels for both Maaseik and Venlo.

α

β

1

β

2

γ

1

γ

2

α Longitudinal dispersion coefficient β Dead zone coefficient

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` 0 50 100 150 200 250 300 350 31-7-2007 2-8-2007 4-8-2007 6-8-2007 8-8-2007 10-8-2007 12-8-2007 14-8-2007 16-8-2007 time dischar ge (m3/s)

Chooz Gendron Angleur Lixhe (Vise) Sint Pieter Salzinnes Smeermaas Loozen Borgharen dorp Megen Bunde

Figure 3.2 Discharges (m3/s) during the period 31 July – 16 August 2007

3.1.3 Exposure scenarios of cypermethrin and chlorpyrifos spills

In our anlysis of the performance of the MAM (see Appendix A), we concluded that the MAM could be use to estimate concentration levels in a worst scenario, and by considering decay of the polluntant (in the case of organic micro pollutants) a more realistic estimation can be done.

We simulated different scenarios of the accidental spills of about 64 kilo chlorpyrifos and 12 kilo cypermethrin in the River Meuse in order to include different decay rates (k) of processes, i.e. hydrolysis, photodegradation. We defined the following scenarios:

cypermethrin chlorpyrifos

scenario 0 Discharge of 12 kilo and no decay Discharge of 64 kilo and no decay scenario 1

Discharge of 12 kilo and process hydrolysis (half-life value = 50

days)

Discharge of 64 kilo and process volatilization (half-life value = 12

days) scenario 2

Discharge of 12 kilo and process photodegradation (half-life value =

100 days)

Discharge of 64 kilo and process hydrolysis (half-life value = 25

days)

scenario 3 -

Discharge of 64 kilo and process photodegradation (half-life value =

58 days)

scenario 4 -

Discharge of 64 kilo and decay rate is the sum of decay rates of volatilization, hydrolysis and

photodegradation

The MAM uses decay rates (1/day). The half-life values can be converted to decay rates by using the following equation:

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ln(2)

decay half life

k

₋

=

where kdecay is the decay rate (1/day) and khalf-life is the half-life value (day). 3.1.4 Environmental Concentrations (EC)

This paragraph presents the results of the scenarios as the Environmental Concentrations (EC) at 8 locations in the Netherlands. Table 3.1 presents the name of the locations, the approximate distance from the spill and the river kilometre according to the Meuse Alarm Model.

Table 3.1 Name, distance from spill and river kilometre of the locations at which the EC were simulated

Location name Approx. distance from spill _{according MAM (km)} Kilometre according MAM

Eijsden 21 MaasZuid km 4.5

Weir Borgharen 36 Julianakannal km 5

Heel 84 MaasZuid km 68.4

Weir Linne 86 MaasNoord km 68.5

Weir Roermond 101 MaasNoord km 84

Weir Belfeld 118 MaasNoord km 100.8

Weir Lith 217 MaasNoord km 200

Keizersveer 267 MaasNoord km 250

Figure 3.3 Locations at which the environmental concentrations were simulated. In blue the locations for

the ecological risk characterization. In red the locations that are relevant for the drinking water production

The first 5 locations are important for the ecological risk characterization (see Section 3.1.1). The last three locations are important for the drinking water production. Eijsden is located at the border with Belgium, while Heel and Keizersveer are important since they are points of water capture.

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Figuur 3.4 shows the results of the different scenarios for cypermethrin at the stations Eijsden, Heel and Keizersveer after the spill (31 July). Figuur 3.5 shows the results of the 4 different scenarios for chlorpyrifos at the stations Eijsden, Heel and Keizersveer after the spill. The concentrations calculated by the MAM are given every 10 minutes (calculation time step). The peak concentrations (µg/l), including the date of occurrence, and the average concentration (µg/l) within 96 hours when increasing concentrations are presented for all scenarios at the 8 locations in Appendix B.

Cypermethrin Concentration - Scenario 0 Spill = 12 kg and K = 0 1/day

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 5 10 15 20 25 30 35 40 45

Time after spill (day)

C onc entr a tion ( m ic rog/l )

Eijsden Heel Keizersveer

Cypermethrin Concentration - Scenario 1 Spill = 12 kg and K = 0.0139 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 5 10 15 20 25 30 35 40 45

C onc entr a tion ( m ic rog/l )

Cypermethrin Concentration - Scenario 2 Spill = 12 kg and K = 0.0069 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 5 10 15 20 25 30 35 40 45

C onc en tr a tion ( m ic rog/l)

Figure 3.4 Results of the different scenarios for chlorpyrifos concentration at the stations Eijsden, Heel

and Keizersveer. The spill is given in kg and the decay rate (k) in 1/day. Y-axis scale 0-2 µg/l

The following differences were observed between the scenario 0 (total load and no decay) and the other scenarios:

• The differences in the peak concentrations vary depending on the location and increase as the distance from the spill is larger. When decay in considered, the smallest differences are observed at Eijsden, while the biggest differences are observed at Keizersveer. In this case the differences with respect to scenario 0 are:

▪ Cypermethrin: between 20.7 and 64.5 ng/l for scenario 1, and between 10.3 and 32.3 ng/l for scenario 2. These differences from the point of view of the drinking water standard (0.1 µg/l) are not important. However, when looking at the EQO standards (0.1 ng/l), these differences become relevant. ▪ Chlorpyrifos: between 1326 and 449 ng/l for scenario 1, between 675 and

221 ng/l for scenario 2, between 298 and 95 ng/l for scenario 3, and between 2106 and 604 ng/l for scenario 4. These differences are from the point of view of the drinking water standard (0.1 µg/l) and EQO standards (0.1 ng/l) very relevant.

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• By increasing the half-life value with 50% (scenario 2 compared with scenario 1), we found that the differences of these scenarios with respect to scenario 0 were a factor 2 smaller. This means a linear relation between changes in the decay and changes in the concentrations.

• With respect to time when the peak concentration took place at the different locations, we observed the following differences with respect to scenario 0: ▪ Cypermethrin: up to 20 min ealier (scenario 1) at the location Heel, Weir

Roermond, Belfeld, Lith and Keizersveer for scenarios that included decay. ▪ Chlorpyrifos: up to 2 hours ealier (scenario 4) at all locations when decay is

included.

• The differences in percentage between scenario 0 and the other scenarios for the average concentrations within 96 hours and for the peak concentrations were about the same. This means that the definition of environmental concentration may not be affected by changes in the decay.

Chlorpyrifos Concentration - Scenario 0 Spill = 64 kg and K = 0 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45

Time after spill (d)

C onc e n tr a tion (mi cr og/L)

Chlorpyrifos Concentration - Scenario 1 Spill = 64 kg and K = 0.058 1/day

0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45

C o n c entr a ti o n (mic rog/L)

0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45

C o n ce n tr a tion (mi cr og/L )

0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45

C onc e n tr a tion (mi cr og/L)

0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45

Time after spill (h)

C o nc en tr a ti o n ( m ic ro g /L)

Figure 3.5 Results of the different scenarios for chlorpyrifos concentration at the stations Eijsden, Heel

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As mention In chapter 3, hydrolysis is a very important process for the fate of cypermethrin in water systems. This process is also relevant for the fate of chlorpyrifos as well as volatilization and photodegradation. We included these processes in the simulations with the MAM. However, adsorption, another very relevant process for both pollutants, could not be included in the simulations. The partition between the dissolved and the undissolved phase of cypermethrin is a relation between the substance concentration in the water and the concentration in suspended sediments. The Meuse Alarm Model does not give the possibility of modelling suspended sediments. Moreover, the processes sedimentation and resuspension of suspended sediments can not be included. Therefore, we decided to focus on the worst possible scenario, and thus without including absorption.

3.2 Characterization of ecological effects

Ecological effects were determined on the baseline that measurement endpoints are correlated to assessment endpoints. It is presumed that the aquatic species Atlantic salmon, brown trout, and fish community expose to cypermethrin and chlorpyrifos may have a survival response (acute as chronic).

In this study, toxicological endpoint concentrations for acute effects (LC50) and for chronic effects (NOEC) on Atlantic salmon, brown trout and fish community were available from the USEPA ECOTOX database (http://cfpub.epa.gov/ecotox/) and IPCS (1989). The effect measurement given by LC50 values is mainly mortality, while for NOEC the effects measurements are biochemical and reproduction. Biochemical effect measurement correspond to the measurement of biotransformation or metabolism of chemical compounds, modes of toxic action, and biochemical responses in hormones. The LC50 and the NOEC of cypermethrin and chlorpyrifos were implied to the risk characterization. This characterization focuses on risks for the ecosystem and is considered as a general assessment since it uses data that are general for the pollutants, but that may divergent for a specific location. This means that many of the toxic data collected with the species test organisms for the Atlantic salmon, brown trout and fish community may not necessarily be representative for the Meuse basin. However, this data give an indication for the sensitivity of a species (group) for cypermethrin and chlorpyrifos.

Before applying the LC50 and the NOEC USEPA ECOTOX database to the risk characterization, we performed three goodness-of-fit tests to decide wether the dataset follow a normal distribution. To do this we used the program ETX 2.0 of the National Institute for Public Health and the Environment (RIVM) (Van Vlaardingen et al., 2004). The ETX is a program to calculate hazardous concentrations and fraction affected, based on normally distributed toxicity data. Two different types of tests are implemented, based on quadratic (vertical) distance and on the largest vertical distance. Well-known quadratic tests are the Anderson Darling test and the Cramér-von Mises test. The Kolmogorov-Smirnov test is a well-known vertical distance test. The results of the test are presented in Appendix C.

Table 3.2 and Table 3.3 show toxicological endpoint concentrations of the stressor cypermethrin on Atlantic salmon and brown trout for acute (LC50) and chronic (NOEC) effects, respectively. For the species Atlantic salmon 3 LC50 values were found. We selected 8 NOEC values of cypermethrin for Atlantic salmon. For the species brown trout only 3 LC50 values of cypermethrin were found and no NOEC values.

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No data were found on toxicological endpoint concentrations of chlorpyrifos on Atlantic salmon and brown trout. For the fish community, 102 LC50 values and 75 NOEC values of cypermethrin were available for the fish community.

In the case of chlorpyrifos, only toxicological endpoint concentrations were found for the fish community. We selected 175 LC50 values and 16 NOEC values of chlorpyrifos.

Table 3.2 Cypermethrin. acute effect

Species Scientific Name Endpoint Effect Measurement Exposure Duration (Days) Conc 1 (ug/L) Reference Atlantic salmon (Salmo salar) 96-h LC50

(µg a.i./li) MORT 4 2.4 IPCS, 1989

Atlantic salmon (Salmo salar)

96-h LC50

Atlantic salmon

(Salmo salar) LC50 MORT 4 2

McLeese et al..1980 Brown trout

(Salmo trutta)

96-h LC50

(µg a.i./li) MORT 4 2 IPCS, 1989

Brown trout (Salmo trutta)

96-h LC50

Brown trout

(Salmo trutta) LC50 MORT 4 1.2

Stephenson. 1982

Table 3.3 Cypermethrin. USEPA Ecotox. chronic effect. The effect measurement of most NOEC values

is biochemical. Only the last NOEC value has reproduction as effect measurement

Species Scientific

Name Endpoint Effect Measurement

Exposure Duration (Days)

Conc 1 (ug/L)

Salmo salar NOEC

17,20BETA- DIHYDROXY-4-PREGNEN-3-ONE

5 0.33

Salmo salar NOEC

17,20BETA- DIHYDROXY-4-PREGNEN-3-ONE

5 0.015

Salmo salar NOEC

11-KETOTESTOSTERONE 5 0.33

Salmo salar NOEC

11-KETOTESTOSTERONE 5 0.028

Salmo salar NOEC TESTOSTERONE 5 0.33

Salmo salar NOEC REPRODUCTION _{Germ cell count} 5 0.001

When not enough chronic toxicity data were available for a give substance, e.g. NOEC values for brown trout, but enough acute toxicity data, a distribution was determined on the basis of acute data. This curve based on acute data was extrapolated to a chronic curve (Van den Ende, 2006). In this case it was assumed that the effect level for chronic exposure in average was a factor 10 lower than the acute exposure. The curve based on NOEC values lied then a factor 10 lower than the curve for LC50 values. This means that the mean lied a factor 10 lower than the mean that was calculated based on acute toxicity data .

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4 Risk

characterization

4.1 Risk on Atlantic salmon, brown trout and fish community

The following table summaries the means and the standard deviations of the log functions of the toxicological endpoint concentrations of chlorpyrifos and cypermethrin. This is given for Atlantic salmon, brown trout, migratory fish (combination of Atlantic salmon and brown trout) and fish population, which includes seawater and fresh water, depending on the available data. The values for migratory fish consider the values for Atlantic salmon and brown trout together. The characterization was done for the 5 relevant locations for ecological risk characterisation: weir Borgharen, weir Linne, weir Roermond, Befeld and Lith. As indication we defined three categories: 1) less than or equal to 5% (green), 2) between 5% and 20% (yellow), and greater than or equal to 20% (red).

Table 4.1 Number of data, means and standard deviations of the log functions of the toxicological

endpoint concentrations of chlorpyrifos and cypermethrin

Toxicological endpoints Nr of _data _{log Conc}Mean Standard deviation _{log Conc}

Chlorpyrifos - LC50 175 1,7750 1,1174

Chlorpyrifos – NOEC 16 0,5606 0,5298

Cypermethrin - LC50 - Atlantic salmon 3 0,1835 0,2750 Cypermethrin - LC50 - Brown trout 3 0,2758 0,1853 Cypermethrin - LC50 - Migratory fish 6 0,2296 0,2157

Cypermethrin - LC50 - Fish 92 0,7855 0,6420

Cypermethrin - NOEC – Atlantic salmon 8 -1,5806 1,0537

Cypermethrin – NOEC 46 0,7253 1,4898

4.1.1 Acute toxicity

Following acute toxicity, we calculated the PAF of Atlantic salmon, brown trout, migratory fish and fish community for the peak concentrations and the 96 hour average concentration of cypermethrin in the different scenarios. In the case of chlorpyrifos the results only correspond to the PAF of the fish community. We compared acute PAF values calculated with peak concentrations (10 min average) and with 96 hours average concentration in order to standardize effects and give insight in the uncertainty of the prediction. The results of the PAF calculations are given in Table 4.2 and Table 4.3 for peak concentrations and 96h average concentrations of cypermethrin, respectively. Higher risks appeared when the total load of cypermethrin (12 kg) is discharged and even when decay due to hydrolysis or photodegradation may be considered (scenarios 0, 1 and 2). This was observed mainly at location weir Borgharen and weir Linne where the PAF values based on peak concentrations for the species Atlantic salmon, brown trout and the migratory fish community were above 20%. Atlantic salmon was more affected for the discharge of cypermethrin than brown trout, and its PAF reached values up to 37% (at weir Linne). At the same location the maximum calculated PAF for brown trout was 16%.

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The case of the fish community appeared to be different. Only at the location Lith the potentially affected fraction based on peak concentrations resulted under the 5% for all different scenarios of cypermethrin. At the other locations the PAF values were above 5%, with a maximum value of 14% observed at weir Linne in scenario 0, 1 and 2. The differences in the PAF values based on peak concentrations when decay was considered were relative important. In the case of cypermethrin, when decay was included (half-life values 50, scenario 1), the PAF values decreased in about 3% than when no decay was considered (scenario 0).

The results for acute toxicity based on the 96 hour average concentrations in all scenarios were very different in comparison with the PAF values obtained with peak concentrations, since the 96 hour average concentrations were much lower. The PAF values obtained in all scenarios were below 5% for all groups. Furthermore, brown trout and migratory fish community were not potentially affected. Only the fish community presented PAF values up to 3% (at location weir Linne).

The relative difference in acute PAF values by comparing the results obtained with peak concentrations and average concentrations of cypermethrin are in average: 8% for migratory fish (range 0 to 30%) and 6% for fish community (range 1 to 10%).

Table 4.2 Risk quantification: Acute risk of cypermethrin on the basis of peak concentrations and 96 h

concentrations. Green: less than or equal to 5%. yellow: between 5% and 20%. red: greater than or equal to 20%

PEAK CONCENTRATIONS AVERAGE CONCENTRATION 96H SCENARIO Location _{PAF Atlantic}

Salmon PAF Brown Trout PAF Migratory Fish

PAF Fish PAF Atlantic _Salmon PAF Brown Trout PAF Migratory Fish PAF Fish Weir Borgharen 24% 6% 14% 11% 0% 0% 0% 2% Weir Linne 37% 16% 26% 14% 1% 0% 0% 3% Weir Roermond 10% 1% 3% 7% 0% 0% 0% 2% Belfeld 6% 0% 2% 6% 0% 0% 0% 2% Scenario 0 (k=0) Lith 0% 0% 0% 1% 0% 0% 0% 0% Weir Borgharen 22% 5% 12% 10% 0% 0% 0% 1% Weir Linne 34% 13% 23% 13% 1% 0% 0% 3% Weir Roermond 8% 1% 2% 6% 0% 0% 0% 1% Belfeld 5% 0% 1% 5% 0% 0% 0% 2% Scenario 1 (k=0,0139) Lith 0% 0% 0% 1% 0% 0% 0% 0% Weir Borgharen 23% 6% 13% 11% 0% 0% 0% 2% Weir Linne 36% 15% 25% 14% 1% 0% 0% 3% Weir Roermond 9% 1% 3% 7% 0% 0% 0% 1% Belfeld 6% 0% 1% 5% 0% 0% 0% 2% Scenario 2 (k=0,0069) Lith 0% 0% 0% 1% 0% 0% 0% 0%

In the case of chlorpyrifos (64 kilos), the PAF values for acute toxicity at all location, with the exception of Lith, were above 5% in all scenarios. This represented the case of PAF values calculated on the basis of the peak concentration as well as on the basis of 96 hour average concentrations. The highest PAF observed at Linne were between 17 and 19%.

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The differences in the PAF values based on peak concentrations resulted when decay was considered were relative important. In the case of chlorpyrifos, when decay was included (half-life values 58 days, scenario 1), the PAF values decreased in about 3% than when no decay was considered (scenario 0).

The relative difference in PAF values for the fish community by comparing the results obtained with peak concentrations and average concentrations of chlorpyrifos were for acute toxicity on average 6% (range 1 to 11%).

Table 4.3 Risk quantification: Acute risk of chlorpyrifos on the basis of peak concentrations and 96 h

concentrations. Green: less than or equal to 5%. yellow: between 5% and 20%. red: greater than or equal to 20%

PEAK CONC. AVERAGE CONC. 96H SCENARIO Location

PAF Fish PAF Fish Weir Borgharen 18% 7% Weir Linne 20% 10% Weir Roermond 14% 7% Belfeld 12% 8% Scenario 0 (k=0) Lith 6% 4% Weir Borgharen 17% 6% Weir Linne 17% 8% Weir Roermond 12% 6% Belfeld 10% 6% Scenario 1 (k=0.058) Lith 3% 2% Weir Borgharen 17% 7% Weir Linne 19% 9% Weir Roermond 13% 6% Belfeld 11% 7% Scenario 2 (k=0.028) Lith 4% 3% Weir Borgharen 18% 7% Weir Linne 19% 9% Weir Roermond 14% 7% Belfeld 12% 7% Scenario 3 (k=0.012) Lith 5% 3% Weir Borgharen 16% 6% Weir Linne 16% 7% Weir Roermond 10% 5% Belfeld 8% 4% Scenario 4 (k=0.099) Lith 2% 1% 4.1.2 Chronic toxicity

Following chronic toxicity, we calculated the PAF of Atlantic salmon, brown trout and fish community for the 96x10 hour (40 days) average concentration of cypermethrin in the different scenarios. In the case of chlorpyrifos the results only correspond to the PAF of the fish community. We compared the chronic PAF values calculated with the 96x10 hour average concentrations and with the 96 hour average concentrations in order to standardize effects for chronic toxicity and to give insight in the uncertainty of the prediction. The results of the PAF calculations for chronic toxicity are given in Table 4.4 for cypermethrin and in Table 4.5 for chlorpyrifos.

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Chronic toxicity gives a different picture of the potentially affected fraction than acute toxicity. In the case of cypermethrin, Atlantic salmon was seriously affected (PAF values between 38 and 59%). This was also been observed in the PAF values obtained with the 96 hour average concentrations, in which case a maximum value of 87% was calculated (around a factor 2 larger). Brown trout was on the basis of 96x10 hour average concentrations not affected at any location in all scenarios. However, on the basis of 96 hour average concentrations PAF values for brown trout were estimated between 75 and 95%, with the exception of Weir Roermond (PAF below 11%). However, it is important to remember that in the case of brown trout no NOEC values were found and therefore a extrapolation was done. The assumption was that effect level for chronic exposure in average is a factor 10 lower than the acute exposure. The fish community also appeared to be affected by cypermethrin under both concentrations. The 96x10 hour average concentrations resulted in PAF values between 4 and 8%, while the 96 hour average concentrations were factor up to 5 larger. Only at the location Lith, we found PAF values lower than 13% for all scenarios. The rest of the values at the other locations are above 17%. Moreover, we observe chronically a much higher potentially fraction. The PAF values for brown trout are the highest reaching 100% of the species potentially affected at for example weir Linne. The Atlantic salmon has lower PAF values, and the fish community even lower.

Table 4.4 Risk quantification: Chronic risk of cypermethrin on the basis of average concentrations in 96

hours and in 96x10 hours. Green: less than or equal to 5%. yellow: between 5% and 20%. red: greater than or equal to 20%

AVERAGE CONCENTRATION 96H AVERAGE CONCENTRATION 96x10H SCENARIO Location PAF Atlantic

Salmon

PAF Brown

Trout PAF Fish

PAF Atlantic Salmon

PAF Brown

Trout PAF Fish Weir Borgharen 87% 95% 22% 52% 0% 6% Weir Linne 83% 82% 19% 59% 0% 8% Weir Roermond 72% 11% 13% 52% 0% 7% Belfeld 86% 93% 21% 54% 0% 7% Scenario 0 (k=0) Lith 87% 96% 22% 41% 0% 4% Weir Borgharen 86% 94% 22% 51% 0% 6% Weir Linne 82% 75% 19% 57% 0% 8% Weir Roermond 70% 5% 12% 50% 0% 6% Belfeld 86% 92% 21% 52% 0% 6% Scenario 1 (k=0,0139) Lith 86% 94% 22% 38% 0% 4% Weir Borgharen 86% 94% 22% 51% 0% 6% Weir Linne 83% 79% 19% 58% 0% 8% Weir Roermond 71% 8% 12% 51% 0% 6% Belfeld 86% 92% 21% 53% 0% 7% Scenario 2 (k=0,0069) Lith 87% 95% 22% 39% 0% 4%

In the case of chlorpyrifos the results only correspond to the potentially affected fraction of the fish community. The fish community was not affected on the basis of 96x10 hour average concentrations at any location in all scenarios. However, the PAF for chronic toxicity obtained with the 96 hour average concentration gave another picture. In scenarios 0 and 3, the locations weir Borghare, weir Linne, Weir Roermond and Belfeld

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presented PAF values above 20%, and in the other scenarios above 14%. With the exception of the PAF values at Lith in scenarios 5 and 6, all the PAF values for acute as well as for chronic toxicity at the other locations in all scenarios are above 5%. Lith is also the only location with PAF values for the chronic toxicity in all scenarios of chlorpyrifos below 20%.

Table 4.5 Risk quantification: Chronic risk of chlorpyrifos on the basis of average concentrations in 96

hours and in 96x10 hours. Green: less than or equal to 5%. yellow: between 5% and 20%. red: greater than or equal to 20%

AVERAGE CONC. 96H AVERAGE CONC. 96x10H SCENARIO Location _{PAF Fish} _{PAF Fish}

Weir Borgharen 21% 0% Weir Linne 32% 1% Weir Roermond 21% 1% Belfeld 23% 1% Scenario 0 k=0 Lith 7% 0% Weir Borgharen 18% 0% Weir Linne 25% 1% Weir Roermond 15% 0% Belfeld _14% _0% Scenario 1 k=0.058 1/day Lith 2% 0% Weir Borgharen 20% 0% Weir Linne 29% 1% Weir Roermond _18% _0% Belfeld 19% 0% Scenario 2 k=0.028 1/day Lith 4% 0% Weir Borgharen 20% 0% Weir Linne _30% _1% Weir Roermond 19% 0% Belfeld 21% 1% Scenario 3 k=0.012 1/day Lith 5% 0% Weir Borgharen 17% 0% Weir Linne 21% 0% Weir Roermond 11% 0% Belfeld 10% 0% Scenario 4 k=0.099 1/day Lith 1% 0%

4.2 Risk on drinking water production

Table 4.6 and Table 4.7 give an overview of the duration of the period when the concentration of cypermethrin and chlorpyrifos, respectively, exceeded the drinking water standard. The tables also include the start and the end date of these periods. The results are given for the different scenarios of cypermethrin and chlorpyrifos at the relevant locations for drinking water production.

For cypermethrin, at the location Eijsden and Heel the period duration is the same when the entire load is discharged with or without decay (scenario 0, 1 and 2). This is around 1 day and 17 hours for Eijsden and 2 days and 4 hours for Heel. Only at Keizersveer a relevant difference in the duration can be observed between the difference scenarios.

Insecticide contamination of the River Meuse in August 2007. Risk Assessment on the basis of MAM calculations

Insecticide contamination of the

River Meuse in August 2007

Insecticide contamination of the

River Meuse in August 2007

Contents

Acknowledgements

1 Introduction

2 Problem

Formulation

3 Analysis

phase

α

β

β

γ

γ

ln(2)

k

k

=

4 Risk

characterization