MadSci Network: Agricultural Sciences
Query:

Re: How can one find out the amount of pesticides, herbicides, etc in soil?

Date: Tue Jun 13 15:43:16 2000
Posted By: Sally Benjamin, Faculty, Environmental litigation, Risk Writers, Ltd.
Area of science: Agricultural Sciences
ID: 957322411.Ag
Message:

It is very difficult to determine the amount of pesticides in soil, especially if you lack sophisticated equipment. Check out some of the technical requirements for measuring pesticides at EPA's website.

http://www.epa.gov/unix0008/toxics_poisons/region08/toxics/pests/2prod.html

http://www.epa.gov/epaoswer/hazwaste/test/main.htm#Chapter

However, before the commonly-used testing equipment and protocols were available, scientists used bioassays to test environmental toxins. You might use the same techniques. Basically, you expose an appropriate test organism (a pest, a plant, etc.) to several known levels of the material you are concerned about. This can be done in many ways, but the simplest is by serial dilution. Mix a known quantity of the toxic material with a known quantity of "clean" soil and then dilute the mixture. For example, you might start with a mix ten times the recommended application rate (read the label to find out the proper rate of application) and then dilute this down to 1/10th the recommended application rate, 1/100th. 1/1000th. 1/1,000,000th. You will also need a control, i.e. a group of organisms you handle in the same way, except they are not exposed to any toxin in the soil. You then expose test organisms to the contaminated soils, observe the reaction, note the reaction (how they react, how quickly they react, how many react, the level where there is no observable reaction, etc.) and compare the reactions observed to how the test organisms react to soil with an unknown quantity of the toxin and to the behavior of the controls. From the organism's reaction you can estimate the amount of contaminant in the soil. There are, of course, many complicating factors, such as the possibility that other toxic materials might be present in the soil, the fact that some organisms will react more quickly than others, for example. Scientists address these problems by use of controls, special test organisms, and use of large numbers of test organisms.

Be very careful if you conduct experiments with toxic materials like pesticides!!!

Have your science teacher work with you. Choose a toxic material that works on plants, rather than animals (& humans!). Decide what you will do to conduct your test safely, before you begin and how you will make your test soils safe after your experiment is done. Remember that it is illegal to apply pesticides in ways that do that do not follow the label! So, it is very important to read and understand the label. If there is anything you don't understand, talk to your teacher. I suggest you contact your local office of the University Extenstion Service for advice on what organisms to test and what pesticides will be relatively safe to use. Good luck.


Current Queue | Current Queue for Agricultural Sciences | Agricultural Sciences archives

Try the links in the MadSci Library for more information on Agricultural Sciences.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@www.madsci.org
© 1995-2000. All rights reserved.