Environmental Engineering Reference
In-Depth Information
6
Ecotoxicity and Physical-Chemical Data
At the core of all criteria derivation methodologies lies ecotoxicological effects
data. Good criteria must be based on good quality data of adequate taxonomic
diversity. Physical-chemical data are important for proper interpretation of toxicity
test data, for estimation of bioavailability, and for estimation of toxicity for some
classes of chemicals. Thus, criteria derivation methodologies must include clear
guidance regarding how much of what kinds of data are required for calculation of
criteria. A big challenge is finding ways to derive criteria from very small data sets.
Ideally, it would be possible to derive scientifically sound criteria, from the minimum
data sets typically required for pesticide registration procedures. The focus of this
section is to review and address the quality and quantity of data required by existing
methodologies.
6.1
Data Sources and Literature Search
Whatever the derivation methodology, the most reliable and most certain criteria
are derived from the largest and best quality data sets. It is very helpful for a
criteria derivation methodology to include some guidance on where and how to find
data. To avoid perceptions, for example, that a regulator has selected only data from
very sensitive species, or that a chemical producer has selected only data from very
tolerant species, there should be explicit guidance regarding what constitutes a
minimal literature search.
Of reviewed methodologies, the Dutch methodology provides the most detailed
information regarding sources of ecotoxicological and physical-chemical data
(RIVM 2001). For plant protection products and biocides, data from registration
application packets are used, as well as other relevant data. For other substances, data
are drawn from the public literature. A list of data sources is given, which includes
on-line databases (e.g., Current Contents, Biosis, Chemical Abstracts, and Toxline),
internal databases, handbooks (Mackay et al. 1992, 1993, 1995, 1997, 1999), librar-
ies, and even confidential data (note that USEPA (1985), expressly excludes the use
of confidential or privileged data). Data used to derive MPCs must be from original
sources (as opposed to review articles, for example). The scope of the literature
search must be described, and should reach back to at least 1970. If four or more
acceptable chronic studies are available, just a short overview of acute toxicity is
acceptable. However, if data from fewer than four chronic studies exist, then all acute
toxicity data are evaluated. Both freshwater and marine data are collected, if statisti-
cal comparison indicates that they are not different, these data are combined.
In the Danish methodology (Samsoe-Petersen and Pedersen 1995), data are col-
lected from handbooks, databases, and searches of the open literature. Handbooks
include ECETOC (European Centre for Ecotoxicology and Toxicology of
Chemicals 1993), GESAMP (Group of Experts on the Scientific Aspects of Marine
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