IVL Swedish Environmental Research Institute has carried out a two-year research project to determine whether the sewage sludge applied to agricultural land contains pharmaceutical residues that spread into the environment. The sludge was found to contain a number of drugs. However, none of the ground water samples taken on agricultural land showed any detectable levels of pharmaceuticals.
– The drugs that we've looked at seem to bind to the soil but over time appear to break down on site, as we only found traces of a few pharmaceutical compounds in soil that had been treated with sludge, says Jörgen Magner, researcher at IVL Swedish Environmental Research Institute.
Sewage sludge from wastewater treatment facilities is often employed as farmland fertilizer. However, because many drugs are not destroyed in these plants, there is a risk that the sludge contains residues of these substances. It is important to raise awareness on this issue and see to what extent pharmaceuticals from sewage sludge applied to agricultural land contribute to the spread of drugs in the environment.
The focus of the present study was to investigate the extent to which some of our most common pharmaceuticals are eliminated as wastewater passes through treatment plants, as well as what happens to these compounds when they are dispersed in the environment. To this end, studies were carried out on agricultural land fertilized with wastewater effluent. Soil and sludge samples were analyzed and the soil water examined to detect the presence of drug residues. Additionally, tests were conducted in the laboratory to establish whether, and to what extent, different pharmaceutical compounds bind to soil.
Sludge from the treatment plant was found to contain 15 of the 24 investigated pharmaceuticals. In contrast, ground water samples showed no detectable levels of drug residues. Land treated with sludge showed only traces of 4 of the 24 drugs and in low concentration (0.4 - 4.9 nanogram/g dry weight). Laboratory tests revealed that pharmaceuticals with basic or neutral properties bind to soil to a greater extent than those with acidic properties.
– According to these results, the use of sludge on agricultural land constitutes only a small part of the overall dispersion of pharmaceuticals in waterways and the groundwater system in relation to the amount of these compounds that pass through the treatment plant via wastewater, says Jörgen Magner.
At the same he stresses that more research is needed in this area, both about how pharmaceuticals are broken down in the wastewater treatment plant itself and in the environment. There is also a need for more research into how the removal efficiency of pharmaceuticals in wastewater treatment plants can be improved to meet future emission standards.
For more information, please contact: Jörgen Magnér, firstname.lastname@example.org, +46 (0)10-788 66 24
This research study was conducted in collaboration with Hushållningssällskapet Malmöhus and co-financed by the IVL Foundation and LIF – the trade association for the research-based pharmaceutical industry in Sweden.