Physical, chemical and biological characteristics defined as suitable for a certain use of a water resource

Domestic use (human consumption and hygienic purposes)

Recreational use (bathing, boating, aesthetic aspects of landscape, …)

Aquatic life

Water quality : definition

Canals and canalized riversReference systemsystem were human influence is minimal (historic data)

sustainable and self regulated systems

Agricultural use

Fishing

Aquaculture

Industrial use

Energetic uses

Transport

Main surface water uses:

Most demanding uses in terms of water quality.

Compliance of a water body to criteria defined for these uses allow all other uses

Types of water pollution

Nutrients - Temperature - Acidification - Radioactivity

Organic pollutants (carbohydrates, fat, proteins,…)

Factors present in natural ecosystemsPollution = excess

Toxic pollutants

Metals - Organic compounds (organochlorinated and organometallic compounds, phenols, formaldehydes,

solvents,…) - Anions (cyanides, fluorides, sulfides,…) ...

Risk characterisation of toxic pollutants

Notification of new substances produced/imported in EU

Base set data collected and validated

Selection of potentially dangerous substances (tonnage, persistance, accumulation properties, toxicity) out of the 100 000 substances of EINECS (European Inventory

of Existing Chemical Substances)

Lists issued by EEC

Effect assessment

Algae

Invertebrates (planktonic, benthic and sediment dwelling organisms)

Fish

Micro-organisms (STP)

Secondary poisoning

Exposure assessment

PNEC

PEC

Risk characterisation of toxic pollutants

Risk characterisation of toxic pollutants : effect assessment

NOEC : highest test concentration showing no effect (concentration-effect relationship)

Example:

EC50 fish: 500 mg/l

EC50 daphnid: 732 mg/l EC50 algae: 314 mg/l

PNEC aqua: 314 = 314 µg/l1000

Assessment factors to derive a PNEC

= concentration below which unacceptable effects on organisms will most likely not occur.

Use of ecotoxicological data and safety factors

Determination of Predicted No Effect Concentration (PNEC) of the substance

most likely not occur.

Determination of Predicted Environmental Concentration (PEC) of the substance

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s Emissions are estimated for each life cycle stage of the substance:production, formulation, processing (industrial or domestic use), disposal.Emission can be provided by industry or calculated by models on the basis of physico-chemical properties and use categories of the substance.

A Standard environment is defined on local, regional and continental scales.

PECs

When valid monitoring data are available, they are also used; otherways default values are used (worst case scenario)

Risk characterisation of toxic pollutants : exposure assessment

Risk characterisation ratio: PEC / PNEC

If PEC/PNEC <1 No hazard for the environmentIf PEC/PNEC 1 Hazard for the environment

Conclusions:

There is need for further information and/or testing

There is at present no need for further information and/or testing or for risk reduction measures beyond those which are being applied already

There is a need for limiting the risks

Risk characterisation of toxic pollutants

Chemical indicesProvide, through measurements, situation at one moment in time

Risk characterisation of toxic pollutants

Chemical-to-chemical processExtrapolations based on laboratory tests, performed with very few speciesEcotoxicological data available for only very few existing chemicals despite QSARs.Monitoring of only 10-20 substances in important aquatic ecosystems (expensive)Do not consider synergistic, antagonistic and additive effectsDo not consider interactions among communities

Biological monitoringIntegration of perturbations based on monitoring of effects

Bioassessments : analysis of biological communities (observational approach)

Bioassays : early warning systems based on ecotoxicological tests

Bioassessment

Based on changes of community structure Biological indices saprobic indices :

diversity indices :

biotic indices :

Bioindicators

planktonic or pelagic (bacteria, protozoans, rotifers, fish)

linked to substrata (diatoms, macroinvertebrates, macrophytes)

identification to species level organic pollution

stressed environment reduced diversity due to particular sensitivity of some species and some species favoured

qualitative data (presence/absence of species)quantitative data (relative abundance or absolute density)

> 60% of biotic indices based on macroinvertebratesubiquitous, abundant, easy to collecteasy to identifylong life spans (record of environmental quality)sedentary (representative of local conditions)comprise representatives of several phyla with different sensitivitiesto pollution

Some states have included such indices into their legislation (Germany, Belgium,…)

Canals and canalized riversMethods directly applicable

planktonic and pelagic specieschironomid pupal exuviae system

Use of artificial subtrata has been validatedmacroinvertebratesdiatoms

Biotic indices

« Xenobiotically-induced variation in cellular or biochemical components or processes, structures, or functions that is measurable in a biological system or sample » (NRC, 1987).

Main type of biomarkers:

biomarkers of the nervous system

biomarkers of the reproductive system

biomarkers of the immunity system

biomarkers relative to genetic material

Suitable organisms for routine bioassays:

must be sensitive to factors under consideration

must be widely distributed and readily available in good numbers

throughout the year

should have economic, recreational or ecological importance

should be easily cultured in the laboratoryfish, invertebrates and planktonic organisms

Biomarkers

mixed function oxidases

regulatory enzymes

behavioural effects

Validation still needed (response-curve relationship; extrapolation of laboratory data to the situation prevailing in situ; development of tests carried out in situ) before implementation in legislation.

Biomarkers

Some biomarkers provide information on the type of pollution detected

High sensitivity Early warning systemsPrevention of damages to

ecosystems

Phytoplankton0.5 - 20 µm

20 - ~50 µm

Food webs in aquatic ecosystems

Bacteria0.5 - 10 µm

Protozooplanktonciliates 20 - 200 µmflagellates 2 - 20 µm

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