Characteristics, Distribution, and Source Analysis of the Main Persistent Toxic Substances in Karst Groundwater at Jinan in North China

Table 3

Quality evaluation of toxic heavy metals in fractured karst water.

Evaluating compounds	I		II		III		IV		V
	Groundwater quality standard (mg/L)	Fraction of samples meeting the standard (%)	Groundwater quality standard (mg/L)	Fraction of samples meeting the standard (%)	Groundwater quality standard (mg/L)	Fraction of samples meeting the standard (%)	Groundwater quality standard (mg/L)	Fraction of samples meeting the standard (%)	Groundwater quality standard (mg/L)	Fraction of samples meeting the standard (%)
As	≤0.001	99.48	≤0.001	0	≤0.01	0	≤0.05	0.52	>0.05	0
Cd	≤0.0001	56.19	≤0.001	41.75	≤0.005	2.06	≤0.01	0	>0.01	0
Cr^6+	≤0.005	89.18	≤0.01	4.64	≤0.05	3.61	≤0.10	1.55	>0.10	1.03
Pb	≤0.005	99.48	≤0.005	0	≤0.01	0.52	≤0.10	0	>0.10	0
Hg	≤0.0001	100	≤0.0001	0	≤0.001	0	≤0.002	0	>0.002	0