Investigating Environmental Health Risks (Developed by SEPUP)

1. Identifying Risk

As students understand that different risks can be compared on a quantitative basis - a fundamental concept in risk management - they also realize that personal factors play an important role in decisions regarding environmental health risks. Students consider personal actions they might take to reduce their exposure to environmental health risks in their lives.

2. Sampling

Students review the concept of environmental health risks and investigate one environmental risk: contaminated fish due to industrial activities on a lake. The process of sampling to collect information about a larger population, group, or area is introduced. Students draw samples from a set of colored fish that represent a population of fish. Students investigate the effect of sample size on accuracy of, and confidence in, inferences about the population from which the sample was drawn. They consider the use of data obtained by sampling to make predictions about environmental health risks.

3. Environmental Health Risks

Students are formally introduced to the concept of environmental health risks as they read a case study of a Super Fund site. Students use evidence to support a decision about exposure to this risk. Assessment of the ability to identify evidence and trade-offs is introduced.

4. Parts per Million

Students perform a serial dilution of copper chloride to develop the concept of parts per million (ppm) as a way of expressing the concentration of a solution. Copper chloride is then reacted with ammonia to demonstrate how chemical tests can reveal concentrations less than those visible to the human eye.

5. Acute Toxicity

Students investigate toxicity testing in animals as one way in which environmental health risks are studied. They collect and investigate data from a simulation of acute toxicity testing of a potentially toxic substance (PTS) in rats. A reading on the toxicity of substances in humans is provided.

6. Chronic Toxicity

Students investigate chronic toxicity by examining data from tests of chronic toxicity of PTS. The idea that tests on animals can be used to predict health effects in humans is discussed. A reading on the use of animal testing to determine acute and chronic toxicity of substances in humans is provided.

7. Testing for Pesticide Residues

Students perform a simulated test for pesticide residues in foods. They develop an understanding that all testing procedures are destructive (foods are generally crushed or pureed) and rely on statistical methods (portions of the food are sampled and tested). Therefore, they realize that no one has tested the actual food they eat. Students discuss limitations in testing procedures and interpretation of results. They also discuss how results are used to conduct risk assessments and how a variety of factors might influence decisions to eat a food.

8. Evaluating Risk

The class discusses the types of data scientists use to evaluate environmental health risks. Students then read about two environmental health risks: lead and MTBE. Applying the knowledge and skills developed throughout the module, they evaluate the relative significance of these health risks.