(TWN briefing paper, 3rd meeting of the BSWG, 13-17 October 1997, Montreal)
Working Group on Biodiversity
Forum Environment and Development, Germany
For more than ten years it has been known that low concentrations of pesticides in the environment and food can have negative effects on male fertility (Eliason 1985). The complex regulation of male fertility is known to be very susceptible to externals factors. Alterations of fertility parameters by e.g. pesticides are often the first signs of further adverse effects on human and animal health. In addition, recent scientific reports have stressed that numerous chemicals acting as endocrinal substances are potential threats to children?s development (Herman-Giddens et al. 1997).
Recently, scientists from Egypt and Norway demonstrated that glyphosate, the active ingredient of Monsanto?s widely used herbicide Roundup, exhibits negative effects on the fertility of male white rabbits (Yousef et al. 1995). The animals were treated with glyphosate in sublethal doses of 1/10 and 1/100 of the LD50 dose (380 and 38 mg kg-1 body weight, Smith & Oehme 1992). After a six-week experimental period the animals were allowed to recover from the treatment for a further six weeks. Seven fertility parameters were measured weekly during the whole experiment. As an overall parameter of the physical status of the animals, the body weight was measured.
In contrast to former findings with dogs and rats, glyphosate fed at sublethal levels significantly lowered the body weight of the treated rabbits. All seven observed parameters of semen quality were influenced negatively by glyphosate. Four of these parameters did not return to the levels of the control group during the six-week recovery period:
- semen volume
- sperm concentration
- percentage of abnormal sperms
- methyl blue reduction time (activity of spermatozoa).
The two definitive texts dealing with environmental and toxicological effects of glyphosate (Grossbard & Atkinson 1985; WHO 1994) report no earlier research in this area. Adverse effects of glyphosate on male fertility have up to now not been a matter of concern. This situation clearly changed with the findings of Yousef et al. (1995). The development and market introduction of genetically engineered herbicide resistant Roundup Ready crop plants together with the herbicide by Monsanto will lead to a significant increase of Roundup applied on agricultural land throughout the world. It is established that glyphosate residues in food derived from Roundup treated crops will lead to increased human and animal consumption of the chemical (Grossbard & Atkinson 1985; WHO 1994). Another previously unexpected pathway for ingestion of glyphosate was discovered with recent evidence from Germany that glyphosate and its metabolite AMPA showed up in surface water after application in the surrounding region (Skark et al. 1997). It seems likely that glyphosate may appear in the drinking water sooner or later. This situation is of special importance for regions where water supplies rely largely on surface water itself, as in much of the developing world.
Thus this case of application of modern biotechnology in agriculture shows that adverse effects on human and animal health may occur. The possible reduction of fertility of wild animals might have negative effects on the conservation of biodiversity. Following the precautionary principle as incorporated in the Convention of Biological Diversity export and registration of Roundup Ready crops should only take place after further investigations of the above discussed critical issues.
Eliason, R. 1985. Clinical effects of chemicals on male reproduction. Reproductive Toxicology, R. L. Dixon (ed.). New York: Raven Press, 1985, pp. 161-172.
Grossbard, E.; D. Atkinson. 1985. The Herbicide Glyphosate. London: Butterworths, 1985, 490 p..
Herman-Giddens, M. A.; et al.. 1997. Secondary sexual characteristics and menses in young girls seen in office practice: A study from the pedriatic research in office settings network. Pedriatrics 99: 505-512.
Skark, C.; N. Zullei-Seibert; U. Schottler; C. Schlett. 1997. The occurence of glyphosate in surface water. Research Results Sheet, Institute of Water Research, Dortmund, Germany.
Smith, E. A.; F. W. Oehme. 1992. The biological activity of glyphosate in plants and animals: A literature review. Veterinary and Human Toxicology 34: 531-543.
WHO. 1994. Glyphosate. Environmental Health Criteria 159. Geneva: WHO. 1994, 161 p..
Yousef, M. I.; M. H. Salem; H. Z. Ibrahim; S. Helmi; M. A. Seehy; K. Bertheussen. 1995. Toxic effects of carbofuran and glyphosate on semen characteristics in rabbits. Journal of Environmental Science and Health B30: 513-534.