Diffuse sources contribute to hazardous substances in Danish water environment

Diffuse sources contribute significantly to observed levels of PFOS, lead, barium, mercury, nickel and other substances in areas where the environmental quality standards have been exceeded.

Environmentally hazardous substances (EHS) enter the aquatic environment via point sources, including wastewater discharges and polluted sites, or via diffuse sources. Diffuse sources include run-off from roads and areas without water collection systems, run-off from agricultural and non-agricultural fields, and deposition of airborne substances. Traditionally, focus has been on the contribution from point sources.

Significant contribution of EHS from diffuse sources
Based on Danish data for the years 2000-2017, DHI has carried out a study for the Danish Environmental Protection Agency on the quantification of the contribution of EHS from diffuse sources to the aquatic environment.

The estimates show that diffuse sources contribute considerably to the observed concentrations of EHS in the aquatic environment. As a result, diffuse sources cannot be overlooked when the environmental quality standards are exceeded. This was shown for substances such as PFOS, lead, barium, mercury, nickel, BDE, PAHs and nonylphenol.

Consequently, a strict regulation of point sources alone is not enough to ensure compliance with the environmental quality standards for EHS pollutants in the water environment.

To learn more about the project and environmentally hazardous substances, please contact ecotoxicologist:

Dorte Rasmussen
Tel +45 4516 9316

More information (in Danish):

Article in the periodical Vand & Jord (no. 3, September 2021, pages 110-114).

Report to the Danish Environmental Protection Agency: Kvantificering af tilførsel af miljøfarlige forurenende stoffer fra diffuse kilder til vandmiljøet