This is a pre-solicitation notice for a future contract to support the EPA in assessing ecological and human health risks from contaminants in water, fish, and sediments, and from microbial pathogens in surface waters. The contract is an ID/IQ with a 5-year ordering period and a total potential performance length of up to 78 months, including options and a completion period. The minimum guaranteed contract value is $100,000, with a total maximum ceiling value of $21.7 million. The solicitation will be issued on an unrestricted, full-and-open competitive basis and contains significant organizational conflict of interest restrictions and a "Limitation of Future Contracting" clause that restricts future work with many entities in the regulated industry.