Among the water quality indicators , cfu - 100ml means the number of colony forming units in 100 ml water ; ntu means nephelometric turbidity unit , and for drinking water , 1 mg l 1 ppm one part per million 水質(zhì)指標(biāo)單位中, cfu 100ml表示每100毫升水樣中菌落形成單位數(shù)colony forming unit : ntu為濁度表示單位nephelometric turbidity unit 。對(duì)飲用水而言, 1mg l毫克每公升1ppm百萬(wàn)分之一含量。