International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 3)

For definition of Groups, see Preamble Evaluation.

VOL.: 53 (1991) (p. 515)

CAS No.: 1582-09-8
Chem. Abstr. Name: 2,6-Dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Trifluralin is a selective pre-emergence herbicide used for the control of annual grasses and certain broadleaf weeds. It was first registered for use in 1963.

Trifluralin has been formulated as emulsifiable concentrates, granules and liquids.

Exposure to trifluralin may occur during its production and application and, at much lower levels, from consumption of residues in food and water.

N-Nitrosodi-n-propylamine has been detected in technical trifluralin, and levels of nitrosamines in trifluralin have been restricted in some countries.

5.2 Carcinogenicity in humans

Use of trifluralin was associated with an increased risk for non-Hodgkin's lymphoma in a study in the USA. A study of ovarian cancer in Italy did not suggest an association with exposure to trifluralin. Both results were based on small numbers of exposed subjects. A larger US study showed no association with the occurrence of leukaemia.

5.3 Carcinogenicity in experimental animals

One technical grade of trifluralin (possibly contaminated with N-nitrosodi-n-propylamine) was tested for carcinogenicity in mice and rats by administration in the diet. In female mice, it induced an increased incidence of hepatocellular carcinomas; in the same study, an increase in the incidence of lung adenomas or carcinomas was observed in females. An increased incidence of squamous-cell carcinomas of the forestomach was noted in female mice at the lower but not at the higher dose. In rats, an increase in the combined incidence of follicular-cell adenomas and carcinomas of the thyroid was noted at the lower but not at the higher dose in females.

Another preparation of trifluralin was tested for carcinogenicity in mice by administration in the diet. No increase in tumour incidence was observed.

5.4 Other relevant data

In a single study, trifluralin was embryolethal and increased the incidence of skeletal variants in mice at doses that caused some maternal toxicity.

No data were available on the genetic and related effects of trifluralin in humans.

A commercial trifluralin formulation induced chromosomal aberrations in bone marrow, embryonal cells and the male germ line in mice. Chromosomal aberrations were also induced in plants. Aneuploidy was induced in several lower eukaryotes. There was little evidence for the induction of gene mutation in any test system.

5.5. Evaluation

There is inadequate evidence in humans for the carcinogenicity of trifluralin.

There is limited evidence in experimental animals for the carcinogenicity of technical-grade trifluralin.

Overall evaluation

Trifluralin is not classifiable as to its carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.


Last updated: 21 November 1997

    See Also:
       Toxicological Abbreviations
       Trifluralin (ICSC)
       Trifluralin (IARC Summary & Evaluation, Volume 54, 1992)