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HRS Rule, Section 2.5.2, page 51593

2.5.2:Comparison to benchmarks. Use the following media-specific benchmarks for making the comparisons for the indicated pathway(or threat):

  • Maximum Contaminant Level Goals (MCLGs)-ground water migration pathway and drinking water threat in surface water migration pathway. Use only MCLG values greater than 0.

  • Maximum Contaminant Levels (MCLs)-ground water migration pathway and drinking water threat in surface water migration pathway.

  • Food and Drug Administration Action Level (FDAAL) for fish or shellfish-human food chain threat in surface water migration pathway.

  • EPA Ambient Water Quality Criteria (AWQC) for protection of aquatic life-environmental threat in surface water migration pathway.

  • EPA Ambient Aquatic Life Advisory Concentrations(AALAC)-environmental threat in surface water migration pathway.

  • National Ambient Air Quality Standards (NAAQS)-air migration pathway.

  • National Emission Standards for Hazardous Air Pollutants(NESHAPs)-air migration pathway. Use only those NESHAPs promulgated in ambient concentration units.

  • Screening concentration for cancer corresponding to that concentration that corresponds to the 10-6 individual cancer risk for inhalation exposures (air migration pathway) or for oral exposures (ground water migration pathway; drinking water and human food chain threats in surface water migration pathway; and soil exposure pathway).

  • Screening concentration for non-cancer toxicological responses corresponding to the RfD for inhalation exposures (air migration pathway) or for oral exposures (ground water migration pathway; drinking water and human food chain threats in surface water migration pathway; and soil exposure pathway).

Select the benchmark(s) applicable to the pathway (or threat)being evaluated as specified in sections 3 through 6. Compare the concentration of each hazardous substance from the sampling location to its benchmark concentration(s) for that pathway(or threat). Use only those samples and only those hazardous substances in the sample that meet the criteria for an observed release (or observed contamination) for the pathway, except: tissue samples from aquatic human food chain organisms may be used as specified in sections 4.1.3.3 and 4.2.3.3. If the concentration of any applicable hazardous substance from any sample equalsor exceeds its benchmark concentration, consider the sampling location to be subject to Level I concentrations for that pathway(or threat). If more than one benchmark applies to the hazardous substance, assign Level I if the concentration of the hazardous substance equals or exceeds the lowest applicable benchmark concentration.

If no hazardous substance individually equals or exceeds its benchmark concentration, but more than one hazardous substance either meets the criteria for an observed release (or observed contamination) for the sample (or comparable samples) or is eligible to be evaluated for a tissue sample (see sections4.1.3.3and 4.2.3.3), calculate the indices I and J specified below based on these hazardous substances.

For those hazardous substances that are carcinogens (that is, those having a carcinogen weight-of-evidence classification of A, B, or C), calculate an index I for the sample location as follows:

n
Ci
I = ----
SCi
i=1

where:

Ci = Concentration of hazardous substance i in sample (or highest concentration of hazardous substance i from among comparable samples).

SCi = Screening concentration for cancer corresponding to that concentration that corresponds to its 10-6 individual cancer risk for applicable exposure (inhalation or oral) for hazardous substance i.

n = Number of applicable hazardous substances in sample (or comparable samples) that are carcinogens and for which an SCi is available.

For those hazardous substances for which an RfD is available, calculate an index J for the sample location as follows:

m
Cj
J = ----
CRj
j=1

where:

Cj = Concentration of hazardous substance j in sample (or highest concentration of hazardous substance j from among comparable samples).

CRj = Screening concentration for non-cancer toxicological responses corresponding to RfD for applicable exposure (inhalation or oral) for hazardous substance j.

m = Number of applicable hazardous substances in sample (or comparable samples) for which a CRj is available.

If either I or J equals or exceeds 1, consider the sampling location to be subject to Level I concentrations for that pathway(or threat). If both I and J are less than 1, consider the sampling location to be subject to Level II concentrations for that pathway(or threat). If, for the sampling location, there are sets of samples that are not comparable, calculate I and J separately for each such set, and use the highest calculated values of I and J to assign Level I and Level II.

See sections 7.3.1 and 7.3.2 for criteria for determining the level of contamination for radioactive substances.

 

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