AttachmentE_p-ToluicAcidCalculationWorksheet

4/5/2022
p-Toluic Acid (CAS # 99-94-5)
North Carolina Interim Maximum Allowable Concentration (IMAC) = 35 µg/L
Summary
GW IMAC based on noncancer endpoint
5.0E-03 mg/kg/day
70 kg
0.2 unitless value
WI = average daily human adult water intake4 2 L/day
1000 = conversion factor 1000 µg/mg
Calculated GW Standard using noncancer endpoint 35 µg/L
GW IMAC based on cancer endpoint
RL = risk level 1.0E-06
70 kg
q1* = carcinogenic potency factor (slope factor)5 NA (mg/kg /day) -1
WI = average daily human adult water intake4 2 L/day
1000 = conversion factor 1000 µg/mg
Calculated GW Standard using cancer endpoint NA µg/L
GW IMACs based on published values
NA µg/L
NA µg/L
NA µg/L
NA µg/L
Practical Quantitation Limit (PQL)10 NA µg/L
References
2 Average adult body weight from 15A NCAC 02L .0202 (effective date April 1, 2013).
5 p-Toluic Acid has not been classified by EPA for carcinogenic potential. A cancer potency factor has not been established.
NA = Not available
History
May 29, 2014 - Hercules Incorporated requested IMAC for p-toluic acid.
September 28, 2017 - EPA Superfund Health Risk Technical Support Center, published NC requested PPRTV (EPA/690/R-17/012)
3 RSC=0.1 for nonorganics, 0.2 for organics in accordance with 15A NCAC 02L .0202 (effective date April 1, 2013).
Taste Threshold6
WT = average adult human body weight2
7 Amoore, JE and Hautala E. 1983. Odor as an aid to chemical safety: Odor thresholds compared with threshold limit values and volatiles for 214 industrial chemicals in air and
water dilution. Journal of Applied Toxicology, Volume 3. No. 6.
6 Leffingwell JC and Leffingwell D., Leffingwell and Associates. 1991. Perfume and Flavorist- GRAS Flavor Chemicals- Detection Thresholds. Vol 16, No. 1, Jan/Feb 1991, P. 1-
The NC IMAC for p-toluic acid is based upon a provisional reference dose (p-RfD) developed by the US EPA, Superfund Health Risk
Technical Support Center, National Center for Environmental Assessment, Office of Research and Development. The critical effect in
female rats was a decreased implantation index in rats. (EPA/690/R-17/012)
GWQS = [(RL x WT) / (q1* x WI)] * 1000
GWQS = [(RfD x WT x RSC) / WI] * 1000
Maximum Contaminant Level (MCL)8
Odor Threshold7
RfD = reference dose1
RSC= relative source contribution3
WT = average adult human body weight2
10 PQL not identified
9 SMCL: https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals.
July 17, 2014 - EPA Superfund Technical Support Center letter acknowledging viability of benzoic acid as a surrogate chemical. Asks if DWR would like p-toluic acid pRfD
developed.
North Carolina Interim Maximum Allowable Concentration (IMAC)
1 EPA Provisional Peer-Reviewed Toxicity Value for p-Toluic Acid. 2017. (EPA/690/R-17/012). Shirota, M et al: Screening of toxicological properties of 4-methylbenzoic acid by
oral administration to rats. J Toxicol Sci 33:431.
Secondary Drinking Water Standard (SMCL)9
4 Average water consumption from 15A NCAC 02L .0202 (effective date April 1, 2013).
8 MCL: https://www.epa.gov/your-drinking-water/table-regulated-drinking-water-contaminants#Organic (accessed 10/2017).