Online supporting information for the following article published in Indoor Air
DOI: 10.1111/ina.12207
Chloroanisoles may explain mold odor and represent a major indoor
environment problem in Sweden
Johnny C LORENTZEN1,2*, Stephanie A JURAN1, Maria NILSSON2, Steven NORDIN3, and
Gunnar JOHANSON1
1
Institute of Environmental Medicine, Work Environment Toxicology, Karolinska Institutet,
Stockholm, Sweden.
2
Eurofins Pegasuslab AB, Uppsala, Sweden.
3
Department of Psychology, Umeå University, Umeå, Sweden
*
Corresponding email: johnny.lorentzen@ki.se
TOXICOLOGICAL EVALUATION
Toxicokinetics. Toxicokinetic studies of CAs were found only for PCA. PCA differs from PCP
by a single methyl substitution. The ortho-methylation of PCP by microorganisms is considered
a major source of environmental PCA. In contrast, in mammals, PCP is metabolized almost
entirely to glucuronide and sulfate conjugates, while minor parts are transformed to
tetrachlorohydroquinone (TCH, an oxidation product), and less substituted chlorophenols. PCA,
if produced at all, is only a minor metabolite (NTP, 1993).
On the other hand, PCA is readily demethylated to PCP by porcine hepatic microsomes and in
vivo by rainbow trout, mice and rats (Glickman et. al., 1977, Ikeda and Sapienza, 1995, Ikeda et.
al., 1994, NTP, 1993, Vodicnik et. al., 1980). The main studies are described in the following.
Radiolabelled PCP and PCA were rapidly taken up from ambient water by rainbow trout exposed
at 0.025 mg/L in water. The concentrations of PCA in liver, blood, fat, and muscle 24 h after
exposure to PCA were of the same order of magnitude as that found for PCP, except that fat
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contained tenfold more PCA, i.e. as much as 80 μg/g. PCA was far more persistent with organ
elimination half times of 6-7 days (23 days in fat) versus 6-10 h for PCP (23 h in fat). No signs
of methylation of PCP to PCA were found. However, PCP-glucuronide was detected in bile after
exposure to PCA suggesting demethylation (Glickman et. al., 1977).
Vodicnik et al. studied the disposition and metabolism of 14C-labelled PCA in female mice after
intraperitoneal administration of 20 mg/kg bodyweight in corn oil (Vodicnik et. al., 1980).
Elimination from the tissues was rapid, with half-times ranging from 5 to 10 hours. Excretion
was primarily via urine, where free PCP, PCP conjugate and TCH, were detected. Free PCP and
its conjugate were also present in feces. PCA was not found in urine or feces, suggesting that
PCA is demethylated prior to excretion (Vodicnik et. al., 1980). Disposition of 14C-labelled
PCA given by gavage as single doses of 25 mg/kg in corn oil has also been studied (Ikeda et. al.,
1994). The half times were 8-15 hours in rats and averaged 6 h in rabbits. In rats, 60% of the
urinary radioactivity was attributable to TCH, 3% to free PCP and 29% to conjugated PCP. A
similar pattern was seen in rabbits, although percentages differed (Ikeda et. al., 1994). Ikeda et
al. also studied PCA in beagle dogs and miniature pigs (Ikeda and Sapienza, 1995). PCA was
readily demethylated to PCP by both species, with a half time of 5-8 minutes. Free and
conjugated PCP, but no PCA or TCH, were found in urine from either species. However, traces
of PCA were detected in pig feces (Ikeda and Sapienza, 1995). PCA has been studied extensively
within the U.S. National Toxicology Program (NTP, 1993). In the toxicokinetic study, rats and
mice were administered PCA at doses of 10, 20, or 40 mg/kg by gavage or 10 mg/kg PCA
intravenously. A rapid elimination of PCA and a rapid formation of its main metabolite, PCP,
were seen in both species and for both exposure routes. The area under the concentration-versustime curve of PCA in plasma increased more than proportional to dose at the highest dose,
suggesting metabolic saturation (NTP, 1993).
In conclusion, the few disposition and metabolism studies available for PCA give a fairly
consistent picture across species, with a relatively rapid and complete biotransformation in vivo
to PCP, PCP conjugates and TCH, followed by mainly urinary excretion. As expected PCA tends
to accumulate in fat tissues, in agreement with the high lipophilicity (log Kow 5.5, Table 1). No
toxicokinetic data were found for the other CAs. All toxicokinetic studies in mammals were
carried out with oral administration. However, there are no indications that inhalation exposure
would result in significantly different toxicokinetics.
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Acute and subchronic toxicity. Renner et al. studied the acute toxicity of PCA and a number of
related substances in mice. The oral LD50 values were 318 mg/kg for males and 331 mg/kg for
females. The intraperitoneal LD50 values were similar, 281 mg/kg for males and 293 for females
(Renner et. al., 1986). In the 16-day NTP study, high early mortality, clinical toxicity, and
treatment-related gross observations were noted in rats and mice dosed with more than 100
mg/kg PCA (NTP, 1993). In the 13-week NTP study, most rats and male mice receiving doses of
80 mg/kg or more died before the end of the studies, whereas survival of female mice was
decreased only in the 180 mg/kg group. Clinical findings of toxicity, such as inactivity and
dyspnea, and chemical-related liver lesions were observed in rats and mice at 80 mg/kg/day and
higher doses.
Overall, the acute and subchronic toxicity of PCA can be considered as intermediate with singledose oral LD50 values in rodents of about 300 mg/kg and non-specific effect (body weight,
organ weights) levels at 20 mg/kg/d after repeat dosing.
Genotoxicity and cancer. Siekel et al. studied the potential mutagenic activity of
hexachlorobenzene (HCB) and PCA. No genotoxicity was observed in S. typhimurium (Ames
test), E. coli, or human peripheral blood lymphocytes (Siekel et. al., 1991). McGregor et al.
observed a positive response for PCA in a mouse lymphoma cell forward mutation assay, but
only after metabolic activation with a rat liver S9 mix (McGregor et. al., 1987). In contrast, NTP
reported that PCA was mutagenic in S. typhimurium strains TA98 and TA1537 in the absence
but not in the presence of S9. No clear mutagenic activity was observed with TA100 or TA1535.
An equivocal response was observed in TA100 with rat S9 mix. PCA was positive for induction
of trifluoro-thymidine resistance in mouse lymphoma cells with S9, whereas the response
without S9 was weak and inconsistent. PCA induced sister chromatid exchanges, but not
chromosomal aberrations in Chinese hamster ovary cells (NTP, 1993). NTP further conducted a
2-year carcinogenicity study of PCA. The substance (>99% pure, dissolved in corn oil) was
administered daily by gavage to groups of F344/N rats and B6C3F1 mice (70 animals per dose
group and sex) at doses of 0, 10 (male rats only), 20, and 40 mg/kg body weight. From these
studies NTP concluded that there was some evidence of carcinogenic activity of PCA in male
rats and equivocal evidence in female rats, based on marginally increased incidences of benign
pheochromocytomas of the adrenal medulla. There was some evidence of carcinogenic activity
in male B6C3Fl mice, based on increased incidences of benign pheochromocytomas of the
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adrenal medulla and hemangiosarcomas of the liver, but no evidence in female mice (NTP,
1993). The high PCA dose was also associated with increased incidences of adrenal medulla
hyperplasia and hypertrophy and hepatocellular mixed cell foci in male mice. Neoplastic liver
lesions were observed in both male and female mice. Hyperthermia-related lesions were found in
male rats in the two highest dose groups. These lesions were considered to be indirectly related
to PCA (NTP, 1993).
Reproductive toxicity. No studies on reproductive toxicity were found for any of the CAs.
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