US EPA

1333447 

Technical Report 

Reproductive toxicology - China 

Li, S 

1993 

DART/TER/95003428 

M 

ED. 

WEINHEIM 

English 

Reproductive toxicology is vital for considering the development and function of the male and female reproductive systems, including fertilization, implantation, embryonic and fetal development, parturition and postnatal adaptation. This broad aspect--encompassing reproductive and developmental biology, toxicology, teratology, and pharmacology, in addition to epidemiology, occupational and environmental health and medicine--may be seen overwhelming to hygienists and to toxicologists interested in reviewing and learning about (or participating in) this fascinating science. In general, the survival of any species depends on the integrity of its reproductive system. Genes located in the chromosomes of the germ cells transmit genetic information from previous generations and control cell differentiation and organogenesis. Under normal situations germ cells ensure the maintenance of structures and functions in the organism in its own lifetime and from generation to generation. But human beings now live in an environment in which at least 10,000 chemicals are prevalent and to which approximately 1000 new compounds are added each year. It is the potential toxicity of such chemicals to human beings during their most vulnerable stages of development--conception to birth--that is among the least understood toxicological phenomena. The adverse effects of environmental chemicals on the human reproductive system have become a major issue; incidence of chemically induced germ cell damage and sterility appear to be on the increase. At present, in China in battery factories, the male factory workers occupationally exposed to lead, their rate of abnormal sperm and prevalence of congenital epilepsy and heart disease of children is higher than that of the unexposed controls. The development of children's intelligence were hindered significantly when one or both of their parents were exposed to carbon disulfide at levels greater than 10 mg m(-3); this was in addition to birth defects in their children and their wives experiencing spontaneous abortion. Such effects were all significantly higher than those of the control. Another study indicated that the carbon disulfide may cause sexual dysfunctions and impairment of spermatogenesis among male workers so exposed. A survey of male-sterility in workers exposed to dibromochloro-propane (DBCP) showed that incidence of spermacrasia and sterility of the male workers in a DBCP factory reached the high level of 7.8%. The effects of caprolactam on the maternal function of female workers in a synthetic fibre factory were investigated, results from this study indicated that even at caprolactam concentrations less than 10 mg m(-3) effects were inflicted on the menstrual functions of the exposed female workers. In addition to the foregoing the influence of benzene and toluene on the reproductive function of female workers in the leather shoe making industry were carried out, the result showed that the incidence rate of menstrual disorders in the exposed group was 48.88%, significantly higher than that observed in the control group (16.21%); the incidence rate of menstrual blood anomaly and dysmenorrhoea had a tendency to increase with the length of employment. The incidence rates of spontaneous abortion and gestosis in the exposed group were 4.7% and 22.6% were distinctly higher than those in the control group (2.4% and 10.5%). The adverse effects of toxic chemicals on the reproductive function of human beings and the risk assessment from exposure are difficult to assess due to the complexities of the reproductive process and the long period required for reproductive maturation. Some research work on reproductive toxicology undertaken and published in Chinese journals during the past 5 years are detailed. Finally, some recommendations for investigation on reproductive toxicology in the future are provided. 

Biochemical Studies-General; Biochemical Studies-Minerals; Reproductive System-Pathology; Toxicology-Environmental and Industrial Toxicology; Developmental Biology-Embryology-Descriptive Teratology and Teratogenesis; Developmental Biology-Embryology-Experimental Teratology and Teratogenesis; Public Health: Environmental Health-Air; Hominidae; Muridae