Assessment of Groundwater Quality along the Cooum River, Chennai, Tamil Nadu, India

Table 9

Regression equations based on analyzed parameters.

Year	Regression equation	𝑅^2 value	𝐹 value
	Premonsoon
2009	EC = 36.358 * pH + 0.807 * TDS + 107.888 * BOD + 24.851 * COD − 3.528 * Na + 6124.594 * Pb − 1231.212	0.958	49.555
2010	EC = 2.818 * pH + 0.211 * TDS − 94.336 * BOD + 71.715 * COD + 2.966 * Na + 6154.062 * Pb − 671.780	0.892	17.981
2011	EC = −184.985 * pH + 0.571 * TDS + 66.079 * BOD + 31.193 * COD + 0.332 * Na + 1575.589 * Pb + 487.066	0.945	37.07
	Postmonsoon
2009	EC = −86.422 * pH + 0.594 * TDS + 4.994 * BOD + 25.715 * COD − 0.229 * Na + 2456.061 * Pb + 306.783	0.977	91.861
2010	EC = −45.855 * pH + 0.683 * TDS − 30.021 * BOD + 25.132 * COD − 0.619 * Na + 3254.098 * Pb + 119.508	0.969	67.6
2011	EC = −17.058 * pH + 0.495 * TDS − 10.607 * BOD + 36.501 * COD − 0.134 * Na + 1181.900 * Pb − 476.028	0.969	68.523