Correction to: Natural Resources Research https://doi.org/10.1007/s11053-018-9422-3

The original version of this article unfortunately contained a mistake in the second part of Table 3. The data in last four rows of Table 3, i.e., columns under “Random forests” section have been shifted inadvertently to the previous columns due to a production error. The corrected section of the table is given below.

Machine learning algorithm

Feature extraction

(de-noised)

Feature selection

Retained features

Training data (tenfold cross-validation)

Testing data

Accuracy

ROC

Accuracy

ROC

AN

BG

Overall

Area

AN

BG

Overall

Area

Random forests

No

None

All 21 original variables

76.1

69.8

73.1

0.79

71.0

77.8

72.4

0.78

Yes

None

All 21 original variables

78.9

68.3

73.9

0.8

71.0

81.5

75.9

0.78

Yes

Principal component analysis

First 12 PCs retained

78.9

77.8

78.4

0.81

64.5

85.2

74.1

0.79

Yes

Pearson’s correlation coefficient

First 16 features: Cd Hg Zn Sb Pb Ag Mg Ba Fe S Ca Sr Cu As Mn V

77.5

69.8

73.9

0.79

71.0

81.5

75.9

0.75

Yes

Correlation-based feature selection

11 features: Ag As Ba Ca Cu Hg Mg S Sb V Zn

73.2

69.8

71.6

0.77

64.5

81.5

72.4

0.77

Yes

Information gain ratio

First 12 features: As Zn Cd Ag Hg Mg Pb Sb S Cu Ba Ca

76.1

65.1

70.9

0.77

67.7

81.5

74.1

0.77

Yes

Wrapper–forward feature selection

4 features: S Sb Sr V

70.6

68.3

68.0

0.75

64.5

70.4

67.2

0.75

Yes

Wrapper–backward feature elimination

16 features: Ag Al As Ba Ca Co Cr Cu Fe Hg Mg P Pb S Sr V

73.2

69.8

71.6

0.78

71.0

74.1

72.4

0.79

The original article has been corrected.