Assessing the discharge of pharmaceuticals along the Dutch coast of the North Sea.

This chapter assessed the annual median discharge of over 100 pharmaceuticals to the DCZ. Calculations were based on pharmaceutical concentrations in surface-, sewage-, and industrial water in the Netherlands. In 2002, riverine discharge to the DCZ for individual pharmaceuticals varied from 0 (concentration below LOD) to 27 t yr(-1). However, in 2002 the annual amount was less than 2 t for 75% of the studied pharmaceuticals. The highest loads were calculated for X-ray contrast media, that is, values of 18-27 t yr(-1) for iopromide. The top 20 pharmaceuticals discharged by rivers to the DCZ are dominated by X-ray contrast media (n = 7), followed by antibiotics (n = 6), analgesics/antipyretics/anti-inflammatory drugs (n = 2), beta blockers (n = 2), fibrates/lipid regulators (n = 1), veterinary antibiotics (n = 1), and others (n = 1). The direct discharge (sewage water and industrial water) of pharmaceuticals to the DCZ, in 2002, for individual pharmaceuticals varied from < 0.0009 to 0.27 t yr(-1) for sewage water, and from < 0.0009 to 0.33 t yr(-1) for industrial wastewater. The highest loads were calculated for sotalol (beta blocker) and diatrizoic acid (X-ray contrast medium) in sewage water and industrial wastewater, respectively. The direct discharge of pharmaceuticals to the DCZ is < 5% of that from riverine discharge. The discharge of these pharmaceuticals to the DCZ in 2002 is in the same order of magnitude as the discharge rates of the mandatory OSPAR substances Cd (8.8-10 t yr(-1)) and Hg (3.3 t yr(-1)), and are higher than the discharge rates of the mandatory substance lindane (0.041-0.055 t yr(-1)) and the recommended substance PCBs (0.217 t yr(-1)). Although some pharmaceuticals are discharged in significant amounts to the DCZ, the human and ecotoxicological risks of these highly biologically active compounds are largely unknown. To determine the environmental hazard and risk of discharged pharmaceuticals to the marine environment, future research should focus on a baseline study and a risk assessment of the discharged pharmaceuticals in the DCZ.