The University of Tennessee's Center for Clean Products and Clean
Technologies has developed a hazard evaluation system for TRI chemicals that produces separate rankings for ecological effects and human health
effects, as well as a total hazard score that integrates information
about a chemical's toxicity to humans and ecosystems with information
about chemical characteristics that influence the likelihood of exposure
to a substance.
WHAT DO THE SCORES MEAN?
UTN total hazard scores indicate how a chemical compares with others in terms of its capacity to harm human health, ecosystems, or environmental health generally. The graphic shows where a compound's hazard score falls relative to all chemicals that have been ranked using this system,
indicating whether it is more or less hazardous than most chemicals.
Chemicals that score at the far right end of the scale are significantly
more hazardous (in the worst 10% of all chemicals according to this
scoring system).
All chemicals scored by a system have been placed in "bins" defined by
percentiles (e.g., a chemical's score is in the least toxic 25% of
chemicals scored by a system). The graphic illustrates
which bin a chemical falls in according to each scoring system in
Scorecard. Looking across these different systems, it is possible to
identify chemicals that consistently score as high or low hazards, as
well as chemicals that score high on some measures (such as human health
hazards) but low on others (such as ecological hazards).
STRENGTHS AND WEAKNESSES OF THIS TYPE OF SCORING SYSTEM?
UTN total hazard value scores are based on
toxicity and persistence considerations. Since persistence can be
a useful surrogate for exposure potential, UTN total scores provide an
improved indicator of the potential environmental health impacts of
environmental releases. Moreover, UTN total scores integrate concerns about ecological and human health impacts into a
combined score . This ensures that
chemicals that pose low human health hazards, for example, remain
priorities if they pose high ecological hazards.
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