The effects of Polycyclic Aromatic Compounds (PACs) on terrestrial and benthic invertebrates are used to estimate the risks of soil and sediment contamination. Effects are assessed exposing the organisms to PACs in life cycle tests. In seventy percent of cases this results in highly predictable effects on development of the exposed invertebrates. Len Paumen has now demonstrated that the effects of prolonged exposure can be very different and so risk assessments based on such measurements are more accurate.
Worms, springtails and chironomids
Len Paumen examined the effects of two 'standard' (regulated) and four 'new' (non-regulated) PACs on one or more generations of terrestrial and aquatic invertebrates. The animals; two species of worm, a springtail and a chironomid species were found to exhibit highly predictable arrested development in seventy percent of cases when subjected to the influence of artificially PAC contaminated soil and sediment. However, prolonged exposure also demonstrated that large and unpredictable effects on the life cycle frequently occur, mainly due to exposure to the 'new' PACs. Moreover, a multigenerational experiment revealed that the influence of these toxic substances over several generations is unpredictable. The usual concentration-response relationships changed into an all-or-nothing response with a clear threshold value. This analysis has therefore demonstrated that gradual effects cannot be assumed in risk assessments for soil and sediment contamination.
PACs are ubiquitous in the environment and have therefore been designated as priority toxic substances by the European Union. PACs often determine the need for soil and sediment remediation. Risk limits are determined by means of a risk calculation based on short-term effects of PACs on aquatic organisms. This method is, however, disputed. Len Paumens research has provided opportunities to improve the accuracy of risk a
|Contact: Dr. Miriam Len Paumen|
Netherlands Organization for Scientific Research