N. Degraeve

Cytogenetic and genetic effects of subchronic treatments with organophosphorus insecticides

Male mice (Q strain) received 5 days a week for 7 weeks drinking water containing dichlorvos (2 ppm), dimethoate (0.6 ppm), malathion (8 ppm), methylparathion (0.15 ppm), or trichlorfon (0.5 ppm). At the end of the treatment, no chromosome damage was observed in bone marrow cells, spermatogonia, and primary spermatocytes. Dominant lethal mutation assays were performed to investigate the pre- and postimplantation foetal lethality. Only negative results were obtained.

Mutagenicity, Carcinogenicity, and Teratogenicity of Insecticides

The origin of insecticides is rooted in antiquity. Plinius the Elder recommended arsenic to kill insects as early as 70 A.D. Arsenic sulfide is reported to have been used by the Chinese in the 16th century, and salts of various metals were utilized as insecticides in the 19th century.

Genotoxicity of an organophosphorus insecticide, dimethoate, in the mouse

The effects of dimethoate were investigated in the mouse after acute (10 mg/kg i.p.) or chronic treatment (0.6 ppm, 5 days a week for 7 weeks). Dominant lethal mutations were scored for a 7-week period after the acute dose, and immediately after exposure for the chronic dose. Chromosome damage was also analysed in bone marrow and spermatogonial cells at the same dose levels (from 12 to 48 h after treatment). MMS (60 mg/kg i.p.) was chosen as the positive control. In no experiment did dimethoate show any genotoxicity.

Genetic effects in the mouse of formaldehyde in combination with adenosine and hydrogen peroxide.

Male mice of the Q strain were injected (i.p.) with a synthetic methylene dinucleotide (Ado-CH2-Ado) and with a mixture of formaldehyde and hydrogen peroxide. Neither injection induced any chromosome lesions in spermatogonia. In the dominant lethal mutation test, the mixture of formaldehyde and hydrogen peroxide had an effect throughout spermatogenesis, but only the rate of pre-implantation losses was increased. Injection of Ado-CH2-Ado increased both pre-and post-implantation deaths at the 1st week but only the frequency of pre-implantation losses at the 6th week.

Absence of genetic and cytogenetic effects in mice treated by the organophosphorus insecticide parathion, its methyl analogue, and paraoxon

Male mice (Q strain) received a single i.p. injection of 3 organophosphorus compounds: ethylparathion (10 mg/kg), its methyl analogue (methylparathion, 10 mg/kg), or its phosphate derivative (ethylparaoxon, 0.3 mg/kg). The number of chromosome aberrations observed in bone marrow cells and spermatogonia, and the frequency of pre- and postimplantation foetal lethality obtained in a dominant lethal mutation assay, did not conclusively prove that the tested compounds produced a mutagenic effect.

Cytogenetic effects induced by organophosphorus pesticides in mouse spermatocytes

Male mice (Q strain) received a single i.p. injection of 14 organophosphorus compounds, including 11 insecticides, administered on separate occasions. After a recovery period of 10 to 15 days, the cytogenic effects were analyzed in primary spermatocytes at diakinesis-metaphase I corresponding to the treatment of A4-B type spermatogonia. At the highest tolerated dose, trimethylphosphate (1000 mg/kg), triethylphosphate (300 mg/kg), dichlorvos (10 mg/kg), methylparathion (10 mg/kg), ethylparathion (10 mg/kg), ethylparaoxon (0.3 mg/kg), fenitrothion (1000 mg/kg), methylbromophos (1000 mg/kg), ethylbromophos (1000 mg/kg), dimethoate (10 mg/kg), malathion (300 mg/kg), methylazinphos (1 mg/kg), ethylazinphos (1 mg/kg) and trichlorfon (100 mg/kg) did not produce chromosome damage.

Evaluation of the mutagenic potential of four commercial mixtures of insecticides

Male mice (Q strain) were given a single ip injection at the maximum tolerated dose of one of four commercial mixtures of insecticides: Luxan Tue-Taons (150 g dimethoate and 150 g fenitrothion/litre), Metadipterex (210 g trichlorfon and 270 g methyldemeton/litre), Dynafos (155 g malathion, 60 g dichlorvos and 75 g carbaryl/litre) and Phosan Plus (95 g dimethoate, 100 g malathion and 100 g methoxychlor/litre). At the maximum tolerated doses, Luxan Tue-Taons (60 mg/kg), Metadipterex (15 mg/kg), Dynafos (50 mg/kg) and Phosan Plus (100 mg/kg) did not induce chromosome aberrations in bone-marrow cells, spermatogonia or primary spermatocytes of the mice. No evidence of potential genetic effects was obtained in a dominant lethal mutation assay.

Genetic and Cytogenetic Effects of Fenitrothion

Male mice (Q strain) were injected intraperitoneally with a high dose (i.e., 1 g/kg) of the organophosphorus insecticide Fenitrothion. No increase in the percentage of chromosome aberrations was observed in bone marrow cells and spermatogonia. A dominant lethal mutation assay did not show any enhancement of fetal mortality before or after implantation.