Water quality standards related to human exposure in the Water Framework Directive : Considerations on fish consumption and swimming
Waterkwaliteitsnormen voor humane blootstelling binnen de Kaderrichtlijn Water
19 February 2013, PDF |
44 pages |
Smit CE, Moermond CTA, Ocke M, te Biesebeek JD
RIVM Report 601357011
Water quality standards for human exposure Chemical substances may affect water quality and which may be harmful for humans and ecosystem health. The Water Framework Directive (WFD) requires derivation of water quality standards for substances. For this, guidance has been developed at the European level. Three routes are considered: direct effects on water organisms, effects on predatory birds and mammals that feed on water organisms, and effects on humans via consumption of fish. The most critical route determines the final standard. The Dutch Ministry of Infrastructure and Environment has commissioned RIVM to investigate whether the input for calculation of the human intake via fish is relevant for the Netherlands.
Fish consumption: do we use the right figures? A default value for fish consumption of 115 gram per day is used for calculations. This is a reasonable estimate for several European countries, but a recent food consumption survey shows that the average Dutch person eats far less. Furthermore, fish is not on the menu every day. Consequently, the estimates for intake of substances might be too high and resulting quality standards too strict. It should be noted, however, that there are people that typically like fish and eat a lot more than the average person. It is a policy decision to define the protection goal for setting water quality standards. RIVM therefore does not propose an alternative for the default consumption value, but offers several possibilities for further refinement of quality standards. An option is to include in the assessment of water quality whether or not a water body is actually used for fishing.
Exposure via swimming The potential relevance of swimming as an additional exposure route was investigated. For this, the oral and dermal intake resulting from swimming was estimated by model calculations for a series of compounds, including industrial chemicals and pesticides. Under the current assumptions, the model indicates that risks from swimming are not to be expected. There is no need to include swimming as an additional route for standard setting.