Naphthalene-2-sulphonic acid

Endpoint summary

Description of key information

oral
28 d rat, drinking water; TS: naphthalenesulfonic acids, sodium salt: NOAEL systemic toxicity >= 1835 mg/kg bw/ day due to not observed adverse effects (OECD 407, GLP; BASF AG 1995)
15 w rat, diet; TS: naphthalenesulfonic acids, potassium salt: NOAEL systemic toxicity >= 1000 mg/kg bw/ day due to not observed adverse effects (OECD 415/416, GLP; BASF AG 2003)
dermal
no data available
inhalation
no data available

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The toxicity of naphthalene-2 -sulfonic acid after repeated oral dosing can be assessed by reliable studies which were performed with the respective sodium and potassium salts.

 

oral

In a GLP conform subchronic study according to OECD test guideline 407, naphthalenesulfonic acids, sodium salt (purity 82%) was administered to groups of 5 male and 5 female Wistar rats in drinking water at concentrations of 0 ppm; 600 ppm 3,000 ppm and 15,000 ppm for 4 weeks (BASF AG, 1995).

Food consumption and body weight were determined each week. The animals were examined for evident signs of toxicity or mortality at least once a day. During the weekly weighing the animals were subjected to an additional comprehensive clinical examination. Urinalyses, clinicochemical and hematological examinations were carried out at the end of the administration period. All animals were subjected to gross-pathological assessment, followed by histopathological examinations.

The mean daily test substance intake was about 62; 331; and 1835 mg/kg bw, respectively.

No substance-related findings were obtained. There was also no indication for neurotoxic effects. The no observed adverse effect level (NOAEL) under the conditions of this study was therefore >= 1835 mg/kg body weight.

 

In a reproductive study according to GLP requirements, naphthalene sulfonic acids, potassium salts (purity 99.9%) were administered to groups of 25 male and 25 female healthy young Wistar rats (FO parental generation) as a homogeneous addition to the food in different dietary concentrations, which were adjusted regularly to obtain a constant test substance intake of 0, 100, 300 and 1000 mg/kg bw/day (BASF AG 2003). The study followed OECD test guideline 415 with observation of additional reproductive parameters (extended one-generation study). The F0 animals were treated for ca. 15 weeks.

The study was terminated with the sacrifice and gross necropsy of all F0 animals. The state of health of the F0 rats was checked each day. Water consumption of the F0 parents was determined regularly during the first 10 weeks after the start of the respective study period (once weekly generally over a period of 3 days each), and additionally during gestation for days 0-1, 6-7, 13-14, and 19-20 p .c. (post coitum) and during lactation periods for days 1-2, 4-5, 7-8, and 14-15 p .p . (p.p. = post partum) of the F0 females. Food consumption of the F0 parents was determined regularly during premating (once weekly over a period of 6 days each), and during gestation (days 0-7, 7-14, 14-20) and lactation periods (days 1-4, 4-7, 7-14). In general, body weights of F0 parent animals were determined once weekly (each time for a period of 7 days). However, F0 females were weighed on days 0, 7, 14 and 20 of gestation and on days 1, 4, 7, 14 and 21 of lactation. Blood and urine samples were taken from 12 F0 parental animals per sex and per group shortly before terminal sacrifice. In the F0 animals of both genders organ weights were determined and histopathological examinations were performed in selected organs. Particular attention was focused to the reproductive organs. The measured intakes of NSA potassium salts by the different test groups correlated well with the desired target concentrations.

The following test substance-related findings were observed:

Decreased total bilirubin was observed in both sexes in the high dose group (-24% males; - 33% females) and in the mid dose group (-13% males; - 22% females), but not in the low dose group. The clinical, gross and histopathological examinations as well as organ weight determinations of the F0 parental rats for general signs of toxicity failed to reveal substance-induced effects up to and including the dose of 1,000 mg/kg body weight/day. The isolated findings on bilirubin concentrations are probably associated with the test compound administered. In the absence of any other sign of systemic toxicity, in particular of clinical pathological and pathological alterations, however, the observed decrease in serum bilirubin concentration has no pathognomonic or toxicological relevance.

Thus, under the conditions of the present extended one-generation study the NOAEL (no observed adverse effect level) of 1,000 mg/kg body weight/day could be fixed for the systemic toxicity of the test substance. In addition, there was no indication for neurotoxic effects of the test substance.

 

dermal

no data available

 

inhalation

no data available

Read across justification:

The registration item contains ca. 78.89% of naphthalene-2-sulphonic acid (CAS # 120-18-3) and ca. 6.5 % of naphthalene-1-sulphonic acid (CAS # 85-47-2). These two substances have the same molecular weight and are structurally almost identical. Therefore naphthalene-2-sulphonic acid and naphthalene-1-sulphonic acid and their respective salts are suitable for read across in order to fulfill the data requirements.

Justification for classification or non-classification

Regarding the results of the reliable studies with the respective sodium and potassium salts, the subchronic NOAEL of naphthalenesulfonic acids is considered to be >= 1000 mg/kg bw. due to the missing of adverse effects in the tested doses.

 

There are no indications given to classify naphthalenesulfonic acids for its repeated toxicity.