Table 4 Descriptive statistical analysis of 11 heavy metals in sediment samples of lakes along a rural to urban gradient in central China (Mean±SD)

Cd (mg/kg)

0.50±0.16

0.32 ± 0.06

0.61 ± 0.16

0.76 ± 0.52

0.45 ± 0.11

4

1.904

0.162

As (mg/kg)

6.53±1.89a

10.04 ± 1.05b

10.69 ± 0.85b

10.66 ± 0.84b

11.15 ± 1.49b

4

6.651

0.003**

Co (mg/kg)

19.81±7.54

15.93 ± 1.40

14.12 ± 1.37

16.10 ± 0.95

16.63 ± 1.09

4

1.044

0.417

Ni (mg/kg)

32.10±9.24

43.67 ± 4.25

40.47 ± 3.30

45.38 ± 3.29

44.61 ± 3.50

4

2.867

0.06

Pb (mg/kg)

32.59±6.55

29.51 ± 2.15

62.87 ± 27.83

35.38 ± 4.16

39.06 ± 11.88

4

4.044

0.02

Cu (mg/kg)

105.45±113.98

37.37 ± 5.47

93.72 ± 74.94

46.60 ± 8.85

62.65 ± 35.21

4

0.754

0.571

Zn (mg/kg)

105.75±43.16

95.97 ± 13.15

166.71 ± 4.71

115.36 ± 20.40

134.41 ± 37.27

4

2.947

0.056

Cr (mg/kg)

111.35±43.93

95.50±4.89

111.29±36.18

94.42±6.45

99.78±8.47

4

0.219

0.923

Mn (g/kg)

0.97±0.64

0.42±0.14

0.59±0.10

0.63±0.20

0.71±0.16

4

1.637

0.217

Fe (g/kg)

37.57±12.66

38.64±3.11

38.26±3.01

39.75±3.60

39.90±3.08

4

0.232

0.916

Al (g/kg)

25.77±15.58

23.60±9.40

45.50±3.29

34.45±15.30

33.76±16.50

4

1.517

0.247