7U. S. EPA. Risk assessment guidance for superfund volume i human health evaluation manual (Part A)[ R ]. EPA/541/1 - 89/002, December 1989 : 193 - 198.
8U. S. EPA. Integrated risk information system [ EB/OL]. http:// www. epa. gov/iris/index. html.
9OAK RIDGE National Laboratory. Risk assessment information system [ EB/OL]. http://rais. ornl. gov/tox/tox_ values. shtml.
10OAK RIDGE National Laboratory. Toxicity summary for cadmium in risk assessment information system[EB/OL], http:// rais. ornl. gov/tox/profiles/cadmium.shtml# t41.