D. Schowanek, H. David et al.
Regulatory Toxicology and Pharmacology 2007;49:245–259
Deterministic and probabilistic risk assessments were developed for commercial LAS in agricultural soil amended with sewage sludge; the procedure done according to ILSI Europe’s Conceptual Framework (D. Schowanek, R. Carr et al. 2004. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture-conceptual framework [Regul. Toxicol. Pharmacol. 40 (3), 227-251)] consists of three main steps.
First, the most sensitive endpoint was determined. In the second step, a back-calculation was conducted from the Predicted No- Effect Concentration in soil (PNECsoil) to a safe level of LAS in sludge (here called ‘Sludge Quality Standard’; SQS). In the ﬁnal step, the resulting SQS values were evaluated for consistency and relevance versus available information from agricultural experience and ﬁeld tests.
No buildup, adverse impact on soil fertility, agronomic performance, or animal/human health have been reported for agricultural ﬁelds which have received sludge with high LAS levels for up to 30 years. Additionally, the current assessment, based on an updated dataset and a reﬁned assessment procedure, suggests that the need for a limit value for LAS in sewage sludge cannot be substantiated on a risk basis.
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