Chlordane Still Present In Tecolote Canyon After Thirty Years Of Its Restricted Use

Tecolote Canyon is a Nature Park located on the northern side of the University of San Diego campus, it extends quite a ways up north past mesa college and it exists between homes, colleges, and golf courses. Back in the 1950's, a pesticide commonly known as Chlordane was used to fumigate fire ants, pests, and other small insects that were infesting the area. It took about thirty years after its extensive use for scientists to realize that this pesticide was more harmful than originally thought. Not only was it toxic to the environment and animals in contact with it, but it's persistence in the soil and sediment was high. This means that even after thirty years of its restricted use, Chlordane concentrations could still be present in high amounts in the soil.

Our goal for this project was to access the locations and concentrations of Chlordane throughout the canyon and to speculate as to where the possible sources for contamination were coming from (or still are coming from). Our class was split up among various parts of the length of the canyon and soil samples were taken from numerous locations near a creek that runs through the park. At each sampling site, coordinates were taken from a GPS system that allowed us to later plug these sites into Google Earth to get a better perspective of where each sample was coming from.


From Google Earth, were were able to pin-point each concentration value for Chlordane with its respective location within the sampling area. This was a very helpful method because from the aerial view, we were able to locate possible drainage sources that might contribute to a specific concentration at a site. The samples were taken into the lab and treated with a Chlordane Kit called ELISA that was able to help us measure absorbency values from each sample. From the absorbency values compared to a standard set of absorbency values for the chemical Chlordane, the concentration for each site was able to be calculated.

Most of the calculations led to fairly low concentrations respectively, however there were a few sites that huge concentrations in comparison to the other sites. One of these sites was located at the major drainage site of the golf course, which in fact made the most sense to us. Sadly, golf courses use many chemicals to treat their grasses without paying much attention to the environment surrounding them. The other high level that was found was located near the highway where a confluence of water was located. All surrounding drainage pathways led to this one small location where the water was just stagnated. Also, when discussing this site with the local park rangers, they had mentioned that the location for that was was where a large condo-complex had been built across the street within the past twenty years and they definitely would have been using lots of pesticides to create the garden area and pest control.

Our results were higher than we would have thought, but it really hits home to know that these chemicals really do exist many years after their use. On out part, only measurements about the soil were taken into consideration, but the immense wildlife in the area definitely plays a big role into the contamination as well. It is important to think about the long term effects when using toxic chemicals and how exactly the product is getting disposed of before using them. Lastly, I would just like to point out that our tests were only run for one pesticide that was banned in the 1980's, yet still today pesticides are being used worldwide to a greater extent and it is our responsibility to make sure that we are monitoring their detrimental effects and using them minimally.