Chemistry Reference
In-Depth Information
threatened releases of hazardous substances that may endanger public health or the
environment. The releases of hazardous substances are controlled through the use
of Reportable Quantities or RQs. The US EPA has adopted the five RQs of 1, 10,
100, 1,000, and 5,000 pounds for hazardous substances and RQs for radionuclides of
0.001, 0.01, 0.1, 1, 10, 100, and 1,000 Ci. There are RQs for 44 metals, 27 of which
7.2 REGULATORY APPLICATIONS
QSARs have been used by Australian, Canadian, Danish, European, German,
Japanese, Netherlands, and United States government organizations to predict
physical and chemical properties, environmental fate, ecological effects, and
health effects of organic chemicals (Walker et al. 2002). The Organization for
Economic Cooperation and Development (OECD), through the European Economic
Commission's Technical Guidance Documents, provides guidance on applications
of QSARs to predict the aquatic toxicity, logarithm of the octanol-water partition
coefficient (log K
ow
), soil or sediment organic carbon partition coefficient (Koc),
atmospheric oxidation, bioconcentration factors (BCFs), and biodegradation of
organic chemicals. In the United States, the Toxic Substances Control Act (TSCA)
Interagency Testing Committee (ITC), the Agency for Toxic Substances and Disease
Registry (ATSDR), the US Environmental Protection Agency (US EPA), and the
Food and Drug Administration (FDA) use QSARs to predict aquatic toxicity,
chemical or physical properties, environmental fate parameters, and health effects
of organic chemicals (Walker 2003). While these organizations have used QSARs
for organic chemicals, only Environment Canada, the US EPA, and the ITC have
used SAR- or QSAR-related algorithms to predict the toxicity of metal ions. The
European Chemicals Agency is considering using QSARs to predict the toxicity of
metal ions.
7.2.1 e
nvironment
c
AnAdA
Environment Canada has used a QSAR-related technique, linear solvation energy
relationships (LSERs), during their regulatory activities for inorganic chemicals.
LSERs are described in Chapters 3 and 5, while Environment Canada's activities
are described here. Under Sections 73 and 74 of the 1999 Canadian Environmental
Protection Act, Environment Canada and Health Canada had to
categorize
and
screen
about 23,000 substances on the Domestic Substances List (DSL) for persis-
tence (P), bioaccumulation (B), and inherently toxic (iT) properties (MacDonald
et al. 2002). The DSL was created for the purpose of defining a new substance.
The original list was from January 1, 1984 to December 31, 1986 for all substances
manufactured or imported in Canada, in Canadian commerce, or used for commer-
cial manufacturing. About 5-10% of the DSL substances are inorganic chemicals.
To categorize the inorganic chemicals, Environment Canada formed the Inorganic
Working Group (IWG). The mandate of the IWG was to make recommendations
as to the best possible means to categorize inorganic substances against P and B
and iT criteria, and to screen inorganic substances. The first task was an approach
