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 2

Distribution area of As at different concentration ranges in different years.

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	286.28	38.91	23.41	2.28	1.02
1	229.15	41.12	24.43	2.47	1.00
2	210.34	42.04	25.46	2.66	0.96
3	187.49	42.27	26.29	6.10	0.95
5	177.79	42.46	26.52	10.44	0.74
10	119.30	36.13	24.23	13.60	2.28