The assessment of heavy metals pollution in four study areas.

Table 5: The assessment of heavy metals pollution in four study areas.

Area	Single-factor pollution index								Comprehensive	Pollution
Area	Cd	Cu	Ni	Pb	Cr	Mn	Co	Se	Index	Degree
Pingdi	0.26	0.1	0.22	0.06	0.27	0.21	0.09	0.25	0.23	Safety
Puan	0.53	0.17	0.29	0.08	0.27	0.39	0.17	0.31	0.42	Safety
Xingwen	0.55	0.15	0.41	0.01	0.09	0.17	0.27	0.18	0.42	Safety
Gulin	1.43	0.44	0.51	0.1	0.68	0.77	0.3	0.69	1.1	Light pollution