AttachmentD_p-ToluicAcidSummaryDocument

3/22/2018
Groundwater Standard Summary Document
Division of Water Resources

p-Toluic Acid (4-methylbenzoic acid) (CAS # 99-94-5)

Health Effects Summary
Human health effects associated with oral environmental exposures to p-toluic acid are unknown. Chronic
studies consisting of repeated daily oral gavage exposures in rats have been shown to have reproductive
and developmental effects including reduced epididymal weight, reduced sperm production and motility,
decreased implantation index, and non-reproductive effects including temporal salivation, increased food
consumption, and a moderate increase in aspartate aminotransferase (AST) activity (Shirota et al., 2008).

Data used for Groundwater Standard
U.S. EPA’s Integrated Risk Information System (IRIS) has not established an oral reference dose (RfD)
for p-Toluic Acid.

A systemic threshold concentration can be calculated for p-Toluic Acid in accordance with 15A NCAC
02L .0202(d)(1) using a provisional-Reference Dose (p-RfD) derived from a no-observed-effect-level
(NOEL) of 100 mg/kd-day published in a peer reviewed scientific paper (Shirota et al., 2008). US
Environmental Protection Agency Superfund Health Risk Technical Support Center (EPA) developed the
Provisional Peer Reviewed Toxicity Value (PPRTV) in the form of a p-RfD in September 2017. It is a
preferred reference source per 15A NCAC 02L .0202 (e). See the note below for more information.

U.S. EPA has not evaluated p-Toluic Acid for carcinogenicity via oral exposures. A cancer potency factor
is not available. Therefore, a human exposure concentration associated with an incremental lifetime
cancer risk estimate of 1 x 10-6 cannot be calculated according to the requirements of 15A NCAC 02L
.0202(d)(2).

No odor threshold, taste threshold, federal maximum contaminant level or secondary drinking water
standard has been established for p-Toluic Acid.

Note: Benzoic Acid was originally identified as a structural surrogate for the derivation of an RfD by
RBR Consulting, Inc. on behalf of Hercules Incorporated. US EPA, upon request of the Division of Water
Resources, reviewed the surrogate proposal and acknowledged that benzoic acid appeared to be a viable
surrogate based on similarities in structure, metabolites formed, physiochemical properties, and mouse
oral LD50s. EPA also identified an oral study in rats (Shirota et al., 2008) that could serve as a principal
study for derivation of a pRfD for p-Toluic Acid. At the Division’s request, EPA proceeded with the
development of the p-RfD. The PPRTV was published in September 2017 (EPA/690/R-17/012).

Recommended IMAC

The recommended IMAC for p-Toluic Acid is 35 µg/L (ppb).

Groundwater standards are to be the “lesser of” the criteria in 15A NCAC 02L .0202(d)(1-6).

Use
p-toluic acid is an intermediate in some industrial processes for the oxidation of p-xylene to terephthalic
acid which is used in the manufacture of polyethylene terephthalate. It is also used in the manufacture of
dyes, colorants and paints, and in agrochemicals and anti-corrosive additives.

3/22/2018
Groundwater Standard Summary Document
Division of Water Resources

References
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.

U.S. EPA Drinking Water Standards and Health Advisories. 2012. Office of Water (EPA 822-S-12-001)
https://www.epa.gov/sites/production/files/2015-09/documents/dwstandards2012.pdf

U.S. EPA Office of Pollution Prevention and Toxics. 2005.

U.S. EPA Office of Research and Development (2017) Provisional Peer-Reviewed Toxicity Values for p-
Toluic Acid (EPA/690/R-17/012) https://hhpprtv.ornl.gov/issue_papers/ToluicAcidp.pdf

U.S. National Library of Science Toxicology Data Network (TOXNET) https://toxnet.nlm.nih.gov/.

Letter to NC DENR (now DWR) (July 2014): Re: ASSISTANCE REQUESTED: Toxicity information
for Acetic Acid (CASRN 64-19-7) and p-Toluic Acid (CASRN 99-9-5) and guidance for possible
surrogates. U.S. EPA Office of Research and Development/ Superfund Technical Support Center

Shirota, M; Seki, T; Tago, K; Katoh, H; Marumo, H; Furuya, M; Shindo, T; Ono, H. (2008). Screening of
toxicological properties of 4-methylbenzoic acid by oral administration to rats. J Toxicol Sci. 33(4):431-
45. DOI: 10.2131/jts.33.431

Young WF, Horth H, Crane R, Ogden T and Arnott M. 1996. Taste and odour threshold concentrations of
potential potable water contaminants. Water Research, 30:2, pp. 331-340.