Our Project was an inquiry into the nature and amount of chemicals used on the Carleton College campus. We researched documents, and talked with those in charge of chemical application. Overall, we found that the College made real attempts to balance the desire for “an attractive and healthy campus” with a concern for the risks posed by exposure to the chemicals used to do so. While there are areas that can be improved on, the College has made several ecologically friendly changes to it’s chemical application regime, and continues to seek new, more environmentally friendly chemicals to use in grounds upkeep.

Current Chemical Usage

Other Chemicals Used

Information About the Chemicals Used

Chemical Application Policies

Summary

Resources

Current chemical usage at Carleton College:

In addition to these chemicals:

• The College contracts out every three years to have Iron Chelate applied to pin oaks in front of the library
• Chemlawn applies a selective, post emergent crabgrass treatment (Acclaim) and a broad leaf herbicide on some athletic fields
• Rainbow Tree Co. injects several elms on campus with Arbortec, a systemic Dutch Elm Disease Preventative
• Short term algae control is done in Lyman Lakes with an algaecide and alum
• Hornet / wasp / bee populations are controlled through use of insecticide spray
• 120 tons of a sand/salt mixture is applied to roads and walkways during a typical winter

About the chemicals used on campus:

• Miracid is used to raise acidity in flower beds and pots. It is not organic, but is not poisonous either (although it can irritate)
• Trimec is a broad leaf weed killer used at Nutting House. Although considered by the EPA to not pose a significant threat to health, it contains the chemicals MCPP and MCPA which have been shown to cause birth defects (teratogenicity) and chromosomal damage (mutagenicity) in large doses in laboratory animals.
• Preen is a pre-emergent weed treatment used extensively in shrub beds. It contains trifluralin, which is a suspect carcinogen, suspect mutagen, suspect teratogen, fetotoxin. In addition, it’s can have toxic effects on non-target species. Toxicity risks are as follows: very high for amphibians; high to very high for fish and crustaceans medium for aquatic insects; low to medium for bees; low for birds
• Orthene sees limited use in the Japanese Garden as an insect control. It is a suspect carcinogen, suspect mutagen, fetotoxin, and there is some evidence of hormonal effects
• Round-up is used
• Daconil is a fungicide used on evergreens in the Japanese Garden. Daconil is very toxic to fish and other aquatic mammals, yet it is not toxic to birds or bees. The EPA approves this fungicide and allows it to be applied at certain rates. In some states Daconil can only be purchased by people who have obtained a chemical supervisors license
• Casoron is a pre-emergent selective herbicide used in some evergreen beds. It is not considered to be particularly harmful
• Dynaweed is a pre-emergent herbicide made from corn gluten. It is totally organic and safe, and it’s use has lessened the use of other, more harmful pesticides to a large degree

Chemical Application Policies, and changes in policies:

The College attempts to apply chemicals at times when the campus is empty, such as summer, in order to minimize exposure to chemicals. In applying chemicals, the College attempts to balance the desires of the community, from those who wish to see no weeds on campus, to those who object to any usage of chemicals. There is no established majority opinion on how to balance the two. The College also actively seeks out new, more environmentally friendly ways to manage the campus that are still cost-effective. One of the most important initiatives in the past few years has been the use of Dynaweed to control crabgrass. Dynaweed has been proven to be cost-effective, and keeps the College from having to apply harmful herbicides to fields in the spring, during maximum usage. The college has also purchased a flamer, which is used to burn weeds in the cracks of sidewalks, reducing usage of Round-up. The College is also pursuing a more aggressive cultural practice on turf, promoting healthier turf, and reducing the amount of chemicals used.

Summary and Recommendations:

The College is to be commended for being aware of, and considering, the effects that the chemicals it uses have. The College has actively pursued safer methods of treating the grounds. Many of the more harmful chemicals are used only in limited amounts, in limited areas. However, there is still room for improvement. In particular, about 100 pounds of Preen are used on campus yearly. The College should search effective, cost effective alternative to Preen. Also, there is no recognized standard as to how many weeds the campus should have. An informal sampling indicated that most people would rather see more weeds, than heavy chemical usage. A full College survey should be conducted to clarify where that balance lies.

Resources:

• http://www.pbigordon.com/pdfs/TrimecEncore-SL.pdf
• http://members.aol.com/rccouncil/ourpage/samples.htm
• http://seattletimes.nwsource.com/news/health-science/html98/fert_051798.html
• Conversations with Dennis Easley, Superintendent of Grounds