The Indiana Clean Manufacturing Technology and Safe Materials Institute at Purdue University has developed a hazard evaluation system for chemicals that produces separate rankings for ecological effects and occupational health effects, as well as a total hazard score that integrates both types of hazards. This system, the Indiana Relative Chemical Hazard Ranking System (formerly known as 3P2M), combines 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?
IRCH environmental hazard value scores indicate how a chemical compares with others in terms of its capacity to impact human health, ecosystems, or environmental health generally. The scores combine the UTN total hazard value scores with air, land, and global hazard values that are based on the presence of a chemical on several regulatory and target lists. 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?
The IRCH environmental hazard scores are based on
toxicity and persistence considerations. Since persistence can be
a useful surrogate for exposure potential, these scores provide an
improved indicator of the potential environmental health impacts of
environmental releases. Moreover, Because the IRCH environmental scores include the UTN total hazard value scores, not the UTN (aquatic) ecological efects scores, they also include measures of human health impacts. This makes them more like general environmental health indicators than purely ecological indicators.
ENVIRONMENTAL HAZARD VALUE SCORE (IRCH) FOR MERCURY
Environmental Hazard Value Score (IRCH) = 140
TECHNICAL DETAILS ON HOW SCORES ARE DERIVED
The IRCH system assigns hazard scores between 0 and 100 based on the
following algorithm:
Environmental Hazard = HVwater+ HVair + HVland + HVglobal
The IRCH system is an improvement over other ranking systems because it considers ecological impacts in water, air, and land. In contrast, the UTN system, for example, only considers aquatic ecosystem effects.
Several policy choices influence the rankings that result from use of
this algorithm. First, it is possible to give equal or different weights
to hazard values for the various endpoints within an effect category
(e.g., to give double weight to compounds that harm aquatic life).
Second, some method of assigning hazard values to parameters that lack
data is required (e.g., to treat the absence of data as indicating the
absence of hazard, or to penalize data gaps). IRCH uses several
alternative chemical rankings based on different versions of these
policy choices.
EDF was unable to extend the IRCH system to additional chemicals
because the Scorecard lacks some of data elements that are required by
this system.
REFERENCE
IRCH: IIndiana Relative Chemical Hazard Score. Indiana Clean Manufacturing Technology and Safe Materials Institute.
http://www.ecn.purdue.edu/CMTI/Pollution_Prevention_Progress_Measurement_Method/
Values from Indiana Relative Chemical Hazard Score - CAS Order (Updated 5/22/02)
