Natural Background Level and Contamination of Shallow Groundwater Salinity in Various Aquifers in a Coastal Urbanized Area, South China

Table 3

Groundwater salinity contamination in various cities in the Pearl River Delta.

Contamination levels	Guangzhou	Shenzhen	Foshan	Dongguan	Huizhou	Zhaoqing	Jiangmen	Zhuhai	Zhongshan
Uncontaminated (%)	79.3	86.7	75.8	65	84.4	96.2	80.9	92.3	52.7
Low (%)	16.5	13.3	21	20	12.5	3.8	15.9	7.7	36.8
Moderate (%)	2.1	0	3.2	12.5	3.1	0	3.2	0	10.5
High (%)	2.1	0	0	2.5	0	0	0	0	0