Table 2 Study sites’ water quality

Makuhari Town

Hanamigawa Ward in Chiba City

Shallow well

2.0–3.5

–

–

–

Before 1954^a

Kemigawa Town

Inage Ward in Chiba City

Shallow well

2.0–5.5

–

–

–

Before 1954^a

Shiina Village

Midori Ward in Chiba City

–

–

–

–

–

–

Goi Town

Ichihara City

Shallow well

3.6

230.3

–

92.0

Before 1966^b

Kaneda Village

Kisarazu City

Shallow well

5–10

75.0

7.0

18.4

May 1953^c

Iwane Village

–

–

–

–

–

–

Kisarazu Town

Shallow well

< 10

267.8

12.4

87.0

May 1953^c

Funagata Town

Tateyama City

–

–

–

–

–

–

Nako Town

Shallow well

3.0

196.0

15.8

52.0

September 1953^c

Hojo Town

Shallow well

4.0

156.0

18.9

32.4

September 1965^c

Tateyama Town

Shallow well

5.0

106.8

14.7

19.2

September 1963^d