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

Table 7

Correlation coefficient (𝑟) for different water quality parameters—premonsoon.

Parameter	pH	EC	TDS	BOD	COD	Na	Pb
2009 premonsoon
pH	1
EC	0.251	1
TDS	0.331	0.96	1
BOD	0.217	0.831	0.785	1
COD	0.226	0.867	0.884	0.668	1
Na	0.449	0.926	0.895	0.878	0.768	1
Pb	0.103	0.761	0.819	0.829	0.709	0.821	1
2010 premonsoon
pH	1
EC	0.437	1
TDS	0.447	0.896	1
BOD	0.192	0.782	0.900	1
COD	0.442	0.911	0.863	0.762	1
Na	0.238	0.811	0.941	0.932	0.731	1
Pb	0.420	0.846	0.816	0.758	0.835	0.750	1
2011 premonsoon
pH	1
EC	0.191	1
TDS	0.352	0.950	1
BOD	0.185	0.876	0.859	1
COD	0.229	0.896	0.873	0.764	1
Na	0.370	0.896	0.947	0.888	0.767	1
Pb	0.186	0.856	0.855	0.694	0.874	0.766	1