Table 2 Relationship between of the C, N, P, Si retention values and chosen parameters of the studied reservoirs expressed as the Pearson’s correlation coefficient with its statistical significance

N_ret%

1

1

1

P_ret%

0.5195^b

–

0.6388^a

1

1

1

DSi_ret%

0.4829^b

–

0.7065^a

0.3661^c

–

0.6949^a

1

1

1

TOC_ret%

–

–

–

–

–

–

0.3659^c

–

0.5234^b

1

1

1

L_Input

–

0.4243^b

–

–

–

–

0.3470^c

–

0.3591^c

–

–

–

Q

–

0.4629^b

–

–

–

–

–

–

–

–

–

–

HRT

–

0.3871^c

0.3345^c

–

–

0.3292^c

0.4579^b

–

0.5740^a

–

–

–

W_ret

0.3299^c

0.5731^a

0.3770^c

–

–

0.3621^c

0.5389^a

–

0.6111^a

0.3387^c

–

0.3909^c