ambient water quality criteria for the protection of human health rita schoeny science environmental justice may 26 2004 2 clean act framework protecting restoring u s waters technology based approach effluent limitation guidelines point sources available affordable epa develops guidance states develop enforceable standards using npdes permits nonpoint source program polluted tmdls funding & technical assistance wetlands watershed approaches set implement programs 3 criterion equation generalized a noncarcinogen awqc rfd x rsc bw di j 4 i fi xbaf revised methodology published 2000 incorporated newer methods as described in 99 revisions to cancer non linear low dose extrapolation consumption estimates bioaccumulation factors replaced bioconcentration emphasis on use specific data vs defaults 5 risk new 304 carcinogens will be at 10 6 level recommend state tribes or most highly exposed populations should not exceed approval wide is unlikely fish default
