Risk Assessment and Prediction of Heavy Metal Pollution in Groundwater and River Sediment: A Case Study of a Typical Agricultural Irrigation Area in Northeast China

Table 3

Distribution area of As at different concentration ranges in different years with addition of a pollution source.

Time (year)	Distribution area (km^2)
	> 1.0 μg/L	> 1.5 μg/L	> 2.25 μg/L	> 3.5 μg/L	> 4.25 μg/L
0	295.09	42.04	24.88	4.63	3.83
1	242.75	43.21	25.69	4.67	3.84
2	220.01	44.06	26.53	4.76	3.89
3	212.73	45.01	27.52	3.51	3.99
5	228.14	50.28	30.65	13.38	4.77
10	135.80	35.95	27.31	14.24	3.23