By: Henning-de-Jong,I (Department of Environmental
Science, Radboud University Nijmegen, Nijmegen, The Netherlands.
i.henning@science.ru.nl) ； van-Zelm,R Huijbregts,MA de-Zwart,D van-der-Linden,TM
Wintersen,A Posthuma,L van-de-Meent,D
Although risk assessments on a per-chemical basis are required during the
registration procedure of pesticides, cumulative risks from the use of all
pesticides on the variety of crops in a catchment area of a river are not
assessed. The present study aimed to rank pesticides used in outdoor
agricultural practice within the catchment of the rivers Rhine, Meuse, and
Scheldt according to their potential toxic impact on the North Sea coastal
ecosystem. Toxic pressure calculations (based on steady-state concentrations
calculated with a multimedia fate model) and species-sensitivity
distribution-based risk estimations were performed for pesticide emissions in
the years 1998 (189 pesticides) and 2004 (133 pesticides). A ranking was
established according to the relative contribution of single pesticides and crop
types to the overall toxic pressure. Calculations were performed
probabilistically to deal with parameter uncertainties. Only a few pesticides
and crop types dominate overall toxic pressure because of emissions in both
years, and the uncertainty appears to be caused largely by uncertainties in
interspecies variances of aquatic toxicities. For 1998, these pesticides were
fentin-acetate, with a median relative contribution (RCx) to the toxic pressure
of multiple chemicals on an ecosystem of 0.43. For 2004, the pesticides that
contributed most were pencycuron and paraquat-dichloride, with a median
RCx, of 4.4 x 10(-2) and 3.9 x 10(-2), respectively. Pesticides applied to
potato cropland and fruit trees contributed most to the overall toxic
pressure.
没有评论:
发表评论