Rivers clean themselves quickly when pollution is not too great, so long as the water is moving and in contact with plants, soil and rock.
在污染不太严重时，河水只要是流动的而且能接触植物、土壤、岩石，自身很快就会变清洁。
2
The place is so serious pollution of skin contact with people the most "intimate", so will focus on cleaning, every day or two application dilute household disinfection is wiped.