Biological evaluation of running waters in Korea, with special reference to bioassessment using the PFU system

A total of six stations in the Han River system were selected for establish ing polyurethane foam units (PFUs) to collect protozoans, including phytoma stigophorans, zoomastigophorans, amoebas and ciliates, in July 1993. In the bioassessment of microbial communities using the PFUs, the number of speci es decreased as pollution intensity increased. The diversity index values c alculated at the main stations generally agreed with the pollution status o f the stations. Anyang-Chon (Chon means stream) showed the lowest diversity value (1.89), and all stations, except Masok and Anyang-Chon, showed diver sity index values ranging from 3.15 to 3.93. The highest heterotrophic inde x (HI) value was detected in Anyang-Chon followed by Masok-Chon. The number of species at the main stations reached a maximum on day 11 of being expos ed to PFUs. The results of S-eq, G and T-90% all suggest that bioassessment s using the PFU system were well matched with pollution status of the water . All microbial variables were significantly correlated with comprehensive chemical pollution indices, P-a and P-b, with correlation coefficients rang ing from r=0.87 to r=0.96.