EarthTalk / E - The Environmental Magazine
Published 11:15 am, Thursday, July 28, 2011
Dear EarthTalk: I've been hearing more and more references to the need to clean up our agricultural practices for reasons pertaining to health, food quality, even global warming. What are the major environmental issues today associated with agriculture?
-- Tony Grayson, Newark, N.J.
What amazes many environmental advocates to this day is how the widespread adoption of synthetic chemical pesticides, herbicides and fertilizers for use in agriculture was dubbed the "Green Revolution," when in fact this post-World War II paradigm shift in the way we produce food has wreaked untold havoc on the environment, food quality and human health.
Agricultural output has certainly increased as a result of these changes, but with the vast majority of the world's farms now relying on petroleum-derived synthetic chemicals to grow crops and petroleum-derived fuels to drive the engines of production -- modern agriculture has become overwhelmingly toxic to the atmosphere and is hastening global warming. The Intergovernmental Panel on Climate Change (IPCC) reports that agricultural land use contributes 12 percent of global greenhouse gas emissions; here in the U.S. almost 20 percent of our carbon dioxide emissions come from agricultural sources.
Intensive use of chemicals isn't good for our nutrition intake, either. Overworked, depleted agricultural soils generate fruits and vegetables with fewer nutrients and minerals than those produced by farmers decades ago. And much of the food we eat is laced with chemicals that end up in our bloodstreams.
Beyond its effect on the food we put in our bodies, modern agriculture generates large amounts of nitrogen, phosphorous and other fertilizers running off into our streams, rivers and oceans, compromising not only the quality of our drinking water and the health of riparian ecosystems, but also causing those huge oxygen-depleted ocean dead zones we hear about in coastal areas such as the Gulf of Mexico.
Yet another issue with modern farming is the amount of animal waste generated and concentrated in small areas, which creates unsanitary and potentially dangerous conditions for the animals and humans alike. And the widespread use of antibiotics on farm animals to keep disease in check results in the development of stronger strains of bacteria that resist the antibiotics used by humans to ward off infection and sickness.
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Also, many worry about the potential impacts of the widespread use of genetic engineering, whereby genes in plants, animals and microorganisms are manipulated to select for specific traits. These genetically modified organisms, reports Greenpeace, "can spread through nature and interbreed with natural organisms," thus contaminating the natural environment in unforeseeable and uncontrollable ways.
The good news is that rapidly increasing consumer demand for healthier food is forcing agribusiness to see the wisdom of moving away from business-as-usual. Organic farming, which eschews chemical fertilizers and pesticides in favor of more natural choices, holds considerable promise for greening up our agricultural systems.
Dear EarthTalk: Why can't plastics of all types, instead of being initially sorted, simply be melted together to be separated later? It must be a monumental and error-prone task to separate truckloads of plastics. -- L. Schand, via email
The reason plastics aren't typically melted together and then separated later is a matter of both physics and economics. When any of the seven common types of plastic resins are melted together, they tend to separate and then set in layers. The resulting blended plastic is structurally weak and difficult to manipulate.
While the layered plastic could in theory be melted again and separated into its constituent resins, the energy inputs required to do so would make such a process cost prohibitive. As a result, recycling facilities sort their plastics first and then melt them down only with other items made of the same type of resin. While this process is labor-intensive, the recycling numbers on the bottom of many plastic items make for quicker sorting.
Many recycling operations are not only reducing sizable amounts of waste from going into landfills but are also profitable if managed correctly.
Manufacturers of plastic items choose specific resins for different applications. Recycling like items together means the reclaimed polymer can be used to create new items just like their virgin plastic forebears. The seven common types of plastic are: No. 1 Polyethylene terephthalate (PET or PETE); No. 2 High-density polyethylene (HDPE); No. 3 Polyvinyl chloride (PVC); No. 4 Low-density polyethylene (LDPE); No. 5 Polypropylene (PP); No. 6 Polystyrene (PS); and No. 7 Other/Mixed (O). One complicating factor is trying to recycle unmarked plastics and those embossed with a No. 7 (representing mixed resins, also known as polycarbonate). According to Earth911, a leading online source for finding recyclers for specific types of items across the United States, in some cases No. 7 plastics can be "down-cycled" into non-renewable resin; in other cases recycling operations just send their unmarked and No. 7 plastics into local landfills.
But even though recycling operations have developed relatively efficient systems for generating reclaimed resins, many environmentalists recommend that consumers still avoid plastics as much as possible.
"Simply recycling these products does not negate the environmental damage done when the resource is extracted or when the product is manufactured," reports EcoCycle, a Colorado-based nonprofit recycler with an international reputation as an innovator in resource conservation. The group adds that over the past half century, the use of disposable packaging -- especially plastic -- has increased by more than 10,000 percent.
Along these lines, products (or packaging) made out of reusable metal, glass or even wood are preferable to equivalent items made from plastic. For starters, an item of metal, glass or wood can be re-used by someone else or recycled much more efficiently than plastic when it does reach the end of its useful life to you.
Wood products and other items crafted out of plant material -- even so-called "polylactic acid (PLA) plastic" made from plant-based agricultural wastes--can be composted along with your yard waste and food scraps, either in your backyard or, if your town or city offers it, through your municipal collection system. Happy reducing, reusing and recycling.
EarthTalk® is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E - The Environmental Magazine (www.emagazine.com). Send questions to: email@example.com. Subscribe: www.emagazine.com/subscribe. Free Trial Issue: www.emagazine.com/trial.