Dangers of Mancozeb

Mancozeb is a widely used chemical in fungal disease management. It is used in turf management, agriculture and horticulture and it is extensively applied to fruit trees, vegetable crops and ornamental plants. Mancozeb protects against a range of fungal diseases including fusarium, blight, and mildew. There are concerns over its toxic effect on humans, wildlife and the environment and restrictions are placed on household use.

Effects on Humans

• Mancozeb inhibits cholinesterase, an important neural enzyme. As a result it is linked to effects on the nervous system. People exposed to mancozeb report symptoms such as nausea, fatigue and headaches. At high doses symptoms include a reduced heartbeat and convulsions. The U.S. Environmental Protection Agency lists mancozeb as a known carcinogenic. Its primary metabolite ethylenethiourea was also linked to thyroid and reproductive problems in animal studies, and concerns were raised over this occurrence in humans.

Effect on the Environment

• Although mancozeb is insoluble in water, in the presence of oxygen and moisture it degrades rapidly to its primary metabolite ethylenethiourea. Ethylenethiourea is both water-soluble and soil mobile, making it a potential groundwater contaminant. While mancozeb only lasts between one and seven days in soil, ethylenethiourea lasts between five and ten weeks. Due to its rapid degradation, regular application of mancozeb is required, which increases groundwater contamination risk with ethylenethiourea.

Effect on Wildlife

• Mancozeb is linked to toxicity in birds such as mallards and the bobwhite quail. It is also highly toxic to aquatic animals such as fishes, tadpoles and crustaceans. Greater toxicity is observed in warm water fishes than fishes living in colder water. The U.S. Environmental Protection Agency is conducting research into the effects of mancozeb on other forms of wildlife.

Precautions

• Mancozeb is used in a dust or spray form and protective clothing including gloves, headgear and boots must be worn during its application. Care should be taken to avoid contaminating animal feed and water supplies during its application and mancozeb should not be used near rivers, lakes or other bodies of water. Mancozeb is also highly flammable, including dust particles released in the air, and should be kept away from open flames.