College of Environment and Resource Jilin University Changchun 130023 P.R. China;
College of Environment and Resource Jilin University Changchun 130023 P.R. China;
College of Environment and Resource Jilin University Changchun 130023 P.R. China;
College of Environment and Resource Jilin University Changchun 130023 P.R. China;
fraction; sequential chemical extraction; quality control;