N˚ of variables

Correlation

p-value

(0.05)

Selections

1

0.574

0.004183

Total phosphorus (mg/L)

2

0.609

0.002041

BOD₅ (mg/L), Total phosphorus (mg/L)

3

0.611

0.001954

COD (mg/L), BOD₅ (mg/L), Total phosphorus (mg/L)

4

0.614

0.00183

COD (mg/L), BOD₅ (mg/L), Total phosphorus (mg/L), Total copper (mg/L)

5

0.614

0.00183

COD (mg/L), BOD₅ (mg/L), Total phosphorus (mg/L), Total copper (mg/L), Total lead (mg/L)