Geographical distribution of sampling stations assessed in the study. Red dots indicated a compost sampling, which is currently being finalised© EU, 2013
JRC study calls for the need to monitor novel pollutants in sewage sludge
The JRC has conducted a screening of typical European situations of sewage sludge in order to support the identification and prioritisation of chemical pollutants in biodegradable waste. In collaboration with European wastewater treatment plants, JRC scientists have evaluated the concentration of 114 chemical substances in 63 samples originating from 15 countries. The compounds included for instance pesticides, personal care products, sweeteners, pharmaceuticals and minor and trace elements. Many of the studied compounds had never been assessed before on such abroad geographic scale. Obtained results were assessed statistically and where possible compared to other findings.
The report presents the result of the screening, concluding that the monitored concentrations did not justify the introduction of new limit values for the considered parameters in the present Directive, as no measurable risk has been identified from the organic compounds in sewage sludge. Comparison to national limit values, where existing, confirmed this. The dataset available and the case study carried out on polychlorinated compounds revealed no scientific evidences to introduce a regulation for classical persistent organic pollutants (POP). However, it reminded the need and usefulness to monitor the situation for emerging pollutants, because the available data base is poor. The authors suggest that a repetition of the exercise should be carried out including more countries, rather than imposing more stringent regulations to monitor single compounds at this time. In addition, they call for a similar exercise on biowaste.
Sewage sludge contains nutrients and organic matter, but also contaminants such as heavy metals, persistent organic pollutants and pathogens. An EU Directive regulates its use in agriculture, aiming to prevent harmful effects on the environment and living beings. However, it only sets limit values for 7 heavy metals: cadmium, copper, nickel, lead, zinc, mercury and chromium in soil as well as in sludge itself. It does not consider persistent organic pollutants (POPs) such as dioxins nor potentially pathogenic organisms like endocrine disruptors, or less investigated compounds, such as engineered nanomaterials, that have been dispersed into the environment.