Journal or Publishing Institution: Journal of Pesticide Reform
Author(s): Cox, C.
Article Type: Report
Record ID: 409
Introduction: Residues of the commonly-used herbicide glyphosate have been found in a variety of fruits and vegetables. Residues can be detected long after glyphosate treatments have been made. Lettuce, carrots, and barley planted a year after glyphosate treatment contained residues at harvest. In California, where reporting of pesticide-caused illnesses is more comprehensive than in other states, glyphosate exposure was the third most commonly-reported cause of pesticide illness among agricultural workers. For landscape maintenance workers, glyphosate ranked highest. Glyphosate can drift away from the site of its application. Maximum drift distance of 400 to 800 meters (1300-2600 feet) have been measured. Glyphosate residues in soil have persisted over a year. Although not expected for an herbicide, glyphosate exposure damages or reduces the population of many animals, including beneficial insects, fish, birds, and earthworms. In some cases glyphosate is directly toxic; for example, concentrations as low as 10 parts per million can kill fish and 1/20 of typical application rates caused delayed development in earthworms. In other cases, (small mammals and birds, for example) glyphosate reduces populations by damaging the vegetation that provides food and shelter for the animals. Glyphosate reduces the activity of nitrogen-fixing bacteria. These bacteria transform nitrogen, an essential plant nutrient, into a form that plants can use. Glyphosate reduces the growth of mycorrhizal fungi, beneficial fungi that help plants absorb water and nutrients. Glyphosate also increases the susceptibility of plants to diseases, including Rhizoctonia root rot, take-all disease, and anthracnose.
Glyphosate is a widely-used, broad-spectrum herbicide that is used to kill unwanted plants in a wide variety of agricultural, lawn and garden, aquatic, and forestry situations. It ranks among the top ten herbicides used in the U.S., both in agricultural and nonagricultural situations. Common brand names are Roundup, Rodeo, Accord, and Vision. This is the second part of a summary of glyphosate’s hazards. Part 1 (JPR 15(3):14-20) discussed the toxicology of glyphosate, its breakdown products, and the other ingredients in glyphosate-containing products. This part discusses human exposure to glyphosate and its ecological effects.
Keywords: glyphosate, glyphosate residues, pesticide illness, glyphosate drift, toxicity, nitrogen-fixing bacteria, mycorrhizal fungi, plant disease
Citation: Cox, C., 1995. Glyphosate, Pt. 2: Human Exposure and Ecological Effects. Journal of Pesticide Reform, 15(4): 14-19.
