Study on the Relationship between Manganese Concentrations in Rural Drinking Water and Incidence and Mortality Caused by Cancer in Huai’an City

Table 4

The Comparison of superscale ratio of Mn in drinking water in different periods.

Variable	Superscale		Qualified
		%		%
Sources
Surface water	22	78.57	6	21.43	19.24	0.00
Shallow groundwater	17	60.71	11	39.29
Deep groundwater	6	21.43	22	78.57
All	45	53.57	39	46.43