The United States EPA has released a new web-based tool, the Causal Analysis/Diagnosis Decision Information System (CADDIS), which simplifies determining 
the cause of contamination in impaired rivers, streams and estuaries.  An impaired body of water does not meet the state or federal water quality standards for 
one or more pollutants.   
  
There are many possible sources of pollution such as industrial waste, municipal sewage, agricultural runoff, naturally occurring minerals in rock and 
sand, and biological materials.Identifying the key sources of pollution is obviously a key stage in remediation action and this system aims to assist in this 
process.  
    
CADDIS provides a standardized and easily accessible system to help scientists find, use and share information to determine the causes of aquatic impairment. 
 Causal analyses look at stressor-response relationships, meaning the effect of a specific substance or activity on the environment.  Examples would include 
excess fine sediments, nutrients, or toxic substances.   
  
The version of CADDIS released today is the first of three.  Future versions will include modules to quantify stressor-response relationships, and databases 
and syntheses of relevant literature on sediments and toxic metals.  
  
CADDIS is available on EPA's Web pages at:  http://www.epa.gov/caddis