Using a combination of the assigned readings and researched outside sources, respond to each of the following with one or more fully developed paragraphs. Cite all sources. Type out your responses in a Word document and submit as an attachment. This assignment is automatically submitted to Turnitin with your submission.

Part I

1. When assessing risk, it is necessary to establish exposure-response relationships. Discuss seven important issues related to exposure-response that need to be considered when assessing ecological risk.

2. Define screening benchmark. Explain how screening benchmarks are used in risk assessment.

3. Define hazard quotient (HQ), and explain what it is used for. A manipulation of the HQ equation gives us a measure of margin of safety. Explain. Define hazard index (HI), and explain what it is used for.

4. When screening for chemicals is performed at sites, what five criteria should be applied to each medium tested to determine whether a chemical is a COPEC, or chemical of potential ecological concern? Explain some considerations for screening against background.

Part II

Read the Xu and Liu (2009) article in Resources. Briefly summarize the article. Include the purpose of the study, a description of the region being studied, a description of the methodology used, any issues, and the authors� conclusions.

This course uses automatic plagiarism checking software (Turnitin). You may submit your work up to 3 times prior to the deadline to check your similarity scores (aim for 10% similarity or less). It takes roughly 15 minutes for the system to process your submission and show the score.

I have attach the test book. please use it more then outside sources