Public health risk assessment of sludge landspreading

In Europe, most of the municipal and some industrial sludge are spread on land. The fertilising properties of these sludge have been recognized for many years and their application on agricultural lands for more than 30 years is considered as an environmental and economical sustainable practice. Because of the presence of chemical substances and pathogens in sludge, precaution measures have to be taken to guarantee food safety and the preservation of soils and other environmental compartments. The landspreading activity has to respect the 86/278 directive and specific member states regulation. Most of these texts include limits values for trace elements (heavy metals, organic compounds) concentration in the sludge.
The objective of this document is to propose a quantitative risk assessment methodology devoted to the specific case of sludge landspreading.
The basic assumption in this work is that sludge landspreading is done in accordance with the regulatory aspects. The quantitative risk assessment is conducted with respect to a conservative approach. For example, all the considered concentrations of chemicals in the sludge correspond to the limit values we suggested.
Calculations using these assumptions show that the global risk levels are acceptable. It means that the suggested limit values are compatible with health regulations. 
Public health risk assessment appears as an effective method to evaluate the relevance of the limit values that have to be regulated in the context of sludge landspreading.