May. 2, 2006
Cornell scientist works on recycling options for farm plastics
With no current infrastructure to recycle the plastics used in agriculture, thousands of tons are burned, buried and dumped each year. The result: Dioxins and other hazardous toxicants are getting into the food chain and air, and plastic debris is choking livestock and wildlife and clogging water channels.
To make "ag plastic" recycling as standard as recycling plastic supermarket bags, Lois Levitan, program leader of Cornell University's Environmental Risk Analysis Program in the Department of Communication, has been spearheading efforts to develop alternatives for New York farmers who now have few disposal options other than open burning. She is identifying potential markets for purchasing used plastic film sheeting from dairies and nurseries and putting together the pieces necessary for a recycling infrastructure.
"We are on the cusp of implementing a pilot collection and recycling program in one or more regions of rural New York," said Levitan, who estimates that at least 2.5 million pounds of plastic film are discarded on New York's dairy farms annually.
Because they are economical and efficient, plastics are being used on farms instead of glass, concrete, wood and natural materials in a variety of ways -- from dairy and silage bags, row and bunker silo covers and bale wraps to mulch films, greenhouse covers and chemical storage containers.
"This is an emerging and growing problem," Levitan said. "The use of dairy films, for example, has exploded just in the past decade."
About half of discarded ag plastic is burned on-farm in inefficient open fires that release high levels of polluting emissions and have become a leading source of dioxins and other hazardous air pollutants, Levitan said.
"Open burning releases much higher levels of dioxins than controlled incineration does, and its release of particulates has been associated with increasing rates of asthma, heart disease, stroke and lung damage," said Levitan. "Burning plastics on farms is one of the worst places, because the emissions deposit at the base of the human food chain, on animal feed, and end up going into milk, meat, fruits and vegetables."
On-farm and backyard burning of plastics is so hazardous that it is illegal in most states. In New York, however, it is only prohibited in urban areas.
Much of what doesn't get burned gets shoved into farm corners or plowed into the fields and becomes a breeding ground for diseases (such as those transmitted by mosquitoes) and an eyesore for tourists. Eventually it gets into waterways, entangling and poisoning birds, turtles and sea mammals, and breaks down into microscopic fragments that are ingested by fish with unknown consequences.
Farmers should be able to recycle plastics, which could be made into fence posts, plastic lumber and garbage bags, become a component in asphalt mix or be re-formed into new ag bags and silage covers, Levitan suggested. Alternatively, they could be burned in controlled incinerators at high enough temperatures to prevent dioxin production.
Levitan also is looking into options that recapture the energy value of plastics. "Plastic resins have very high energy content -- about the same as fuel oil, double the average heat value for coal and nearly three times the value of wood," she said. As fuel costs soar, "this energy factor will become increasingly important."
Levitan, who urges concerned farmers and citizens to cause "a ruckus" with their legislators and agricultural agencies to get ag plastics recycling off the ground, said that producers of the plastic products and packaging also need to take more "product life cycle responsibility."
"It's critical to sow lots of carrots to entice and enable people to do the right thing and, ultimately, to change the culture of open burning," concluded Levitan, who has issued several reports on options for recycling agricultural plastics that are available at http://environmentalrisk.cornell.edu/AgPlastics.