Environmental quality standards for barium in surface water: Proposal for an update according to the methodology of the Water Framework Directive

Abstract - RIVM is proposing new water quality standards for barium in surface water. These standards represent a safe concentration in water for aquatic organisms, for fish consumption by humans and for animals feeding on fish. The update is necessary because new information has become available on the effects of barium on humans, animals and plants. The health based risk limit has become less stringent. This risk limit indicates the intake level without harmful effects on human health.

Barium is a natural compound and humans may be exposed to it via food and drinking water. The amount of barium that humans can ingest daily without health risk is a known factor. This value was used to calculate the maximum allowable concentration in fish for daily lifetime consumption by humans.

Data from the scientific literature show that barium concentrations in fish and shellfish do not exceed this safe concentration for humans. Birds and mammals can be exposed to barium via consumption of aquatic vegetation, but negative effects are not expected for concentrations up to 93 microgram per litre water. This also applies to fish, water fleas and other aquatic organisms. Concentrations in Dutch surface water are generally below this value.

To determine the new standard, RIVM used recent literature on the environmental behaviour and effects of barium and the uptake of barium by plants and animals. The natural presence of barium in the environment was taken into account in calculating the new standard.

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