Groundwater quality in Chennai city along the Cooum river, during the premonsoon (June–July) and postmonsoon (Dec–Jan) for three years, from 2009 to 2011, was analyzed. Groundwater samples were collected from 20 bore wells on either side of the river. The analysis focused on the determination of seven specific water quality parameters, namely, pH, EC, TDS, BOD, COD, Na and Pb, using standard procedures. The statistical analysis, like the mean and standard deviation, coefficient of variance, and correlation, and multilinear regression analysis of the obtained data were carried out. The analysis of the collected samples reveals that the stated water quality parameters have not complied with the WHO standards, and the water is not fit for drinking and domestic purposes. The correlation and multilinear regression analyses suggest that the conductivity has a significant correlation with the other six considered water quality parameters.
Groundwater is a natural precious resource that sustains the basic needs of all living creatures. It cannot be created or supplemented electronically or hydrologically or by any other means [
The Cooum river is 80% more polluted than the treated sewage [
A map showing sampling locations along the Cooum river.
The study area, along the Cooum river in Chennai district of Tamil Nadu, India, lies between latitude 13°4′5.18′′ north and longitude 80°17′9.06′′ east. The Cooum river is the starting point where the municipalities and town Panchayats that lie on either side of the river discharge both treated and untreated industrial effluents and domestic sewage in addition to the bathing of animals, human activities, washing of vehicles directly or by feeder drains into the 16 km length of the Cooum river [
Detail of sample sites along the left side (SL) of the Cooum river.
Site no. | Area | Latitude/longitude | Depth of bore well (m) | Apparent water quality |
---|---|---|---|---|
SL1 | Arumbakkam | 13°4′30.8′′N 80°12′29.43′′E | 33 | Odorless, colorless |
SL2 | Nungambakkam | 13°3′57.27′′N 80°13′56.37′′E | 34 | Odorless, colorless |
SL3 | Chintadripet | 13°80°14′55N 42′′3′59.60′′E | 34 | Odorless, colorless |
SL4 | Chintadripet | 13°4′20.64′′N 80°16′11.27′′E | 35 | Odorless, colorless |
SL5 | Nungambakkam, | 13°3′32.72′′N 80°14′15.82′′E | 33 | Odorless, colorless |
SL6 | MMDA Colony | 13°3′59.42′′N 80°12′49.54′′E | 35 | Odorless, colorless |
SL7 | Choolaimedu | 13°3′34.67′′N 80°13′32.62′′E | 33 | Odorless, colorless |
SL8 | Chinmaya Nagar | 13°3′42.89′′N 80°11′44.15′′E | 34 | Odorless, colorless |
SL9 | Vadapalani | 13°3′23.42′′N 80°12′20.09′′E | 33 | Odorless, colorless |
SL10 | Gopalapuram | 13°3′2.11′′N 80°15′22.76′′E | 32 | Turns yellowish |
Detail of sample sites along the right side (SR) of the Cooum river.
Site no. | Area | Latitude/longitude | Depth of bore well (m) | Apparent water quality |
---|---|---|---|---|
SR1 | Aayiram Vilakku | 13°3′59.72′′N 80°15′28.38′′E | 34 | Odorless, colorless |
SR2 | Anna Salai | 13°4′27.13′′N 80°16′51.48′′E | 33 | Odorless, colorless |
SR3 | Anna Nagar | 13°4′49.15′′N 80°12′16.12′′E | 33 | Odorless, colorless |
SR4 | Anna Nagar East | 13°5′9.70′′N 80°13′13.17′′E | 33 | Odorless, colorless |
SR5 | Periamet | 13°4′55.95′′N 80°16′8.52′′E | 34 | Odorless, colorless |
SR6 | Anna Nagar | 13°5′13.13′′N 80°12′12.63′′E | 33 | Odorless, colorless |
SR7 | Kilpauk | 13°4′53.24′′N 80°14′3.17′′E | 33 | Odorless, colorless |
SR8 | Egmore | 13°4′30.59′′N 80°15′1.62′′E | 32 | Odorless, colorless |
SR9 | Periamet | 13°4′52.49′′N 80°15′33.47′′E | 33 | Odorless, colorless |
SR10 | Purasavakkam | 13°5′15.12′′N 80°14′50.71′′E | 32 | Odorless, colorless |
Water samples were collected from the bore wells at a depth of 32–35 m below the ground level at 20 locations along the Cooum river. Two water samples were collected per year per sampling station covering both pre- and postmonsoon seasons. A total of 120 samples were tested and analyzed for a period of three years (2009–2011). The collected samples were stored in cleaned and well-dried brown polythene glass bottles (2.5 L), with necessary precautions (APHA, 1995) [
The collected samples were analyzed for specific water quality parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), sodium (Na), and lead (Pb) using standard methods as tabulated in Table
Methods used for analysis of quality parameters for the water samples.
Quality parameters studied | Methods used |
---|---|
pH | pH meter |
Electrical conductivity | Conductivity meter |
Total dissolved solids | Evaporation method |
Biochemical oxygen demand | Modified Winkler’s method |
Chemical oxygen demand | Titrated with an excess of K2Cr2O7 |
Sodium | Flame photometry |
Lead | Atomic absorption spectrometry |
Water quality parameters with respect to the WHO standards.
S. no | Parameter | WHO |
---|---|---|
1 | pH | 7.0–8.5 |
2 | Electrical conductivity (EC) ( |
1400 |
3 | Total dissolved solids (mg/L) | 1000 |
4 | Bio chemical oxygen demand (BOD) (mg/L) | 5 |
5 | Chemical oxygen demand (COD) (mg/L) | 10 |
6 | Sodium (mg/L) | 200 |
7 | Lead | 0.01 |
Statistics of three years (2009–2011) groundwater quality data—premonsoon.
Premonsoon | ||||||||
---|---|---|---|---|---|---|---|---|
Parameter | Year | pH | EC |
TDS |
BOD |
COD |
Na |
Pb |
2009 | 8.31 | 2173 | 2677 | 8.34 | 24.2 | 287 | 0.081 | |
Max | 2010 | 8.26 | 2296 | 2713 | 8.35 | 24.6 | 303 | 0.083 |
2011 | 8.3 | 2371 | 2892 | 8.56 | 24.8 | 313 | 0.087 | |
| ||||||||
2009 | 6.85 | 498 | 987 | 4.39 | 13.3 | 130 | 0.025 | |
Min | 2010 | 6.71 | 631 | 1048 | 4.24 | 11.1 | 137 | 0.03 |
2011 | 7.04 | 583 | 1010 | 4.64 | 11.8 | 150 | 0.036 | |
| ||||||||
2009 | 7.51 | 1355 | 1894.15 | 6.8135 | 18.73 | 219.75 | 0.0585 | |
Mean | 2010 | 7.4185 | 1515.95 | 2029 | 6.74 | 18.755 | 226.55 | 0.055 |
2011 | 7.548 | 1523.75 | 2073.5 | 6.8995 | 19.72 | 230 | 0.0642 | |
| ||||||||
2009 | 0.41391 | 570.724 | 575.614 | 1.27868 | 3.4278 | 53.18 | 0.01494 | |
Std. | 2010 | 0.44131 | 536.77 | 577.915 | 1.37405 | 4.0111 | 55.006 | 0.014567 |
2011 | 0.36026 | 559.887 | 585.852 | 1.34849 | 3.9107 | 57.544 | 0.014468 | |
| ||||||||
2009 | 5.51145 | 42.11985 | 30.38904 | 18.76686 | 18.30112 | 24.20023 | 25.53846 | |
CV% | 2010 | 5.9487 | 35.40816 | 28.48275 | 20.3865 | 21.38683 | 25.40013 | 26.48545 |
2011 | 4.7729 | 36.74402 | 28.25426 | 19.54475 | 19.83114 | 25.01913 | 22.53583 |
Statistics of three years (2009–2011) groundwater quality data—postmonsoon.
Postmonsoon | ||||||||
---|---|---|---|---|---|---|---|---|
Parameter | Year | pH | EC |
TDS |
BOD |
COD |
Na |
Pb |
2009 | 7.7 | 2004 | 2605 | 8.97 | 23.7 | 313 | 0.081 | |
Max | 2010 | 7.7 | 2073 | 2673 | 8.39 | 24.3 | 300 | 0.08 |
2011 | 7.75 | 2207 | 2716 | 8.25 | 24.6 | 310 | 0.083 | |
| ||||||||
2009 | 6.7 | 508 | 905 | 4.3 | 10.3 | 120 | 0.03 | |
Min | 2010 | 6.6 | 557 | 981 | 4.37 | 10.9 | 127 | 0.03 |
2011 | 6.7 | 567 | 993 | 4.46 | 11.3 | 133 | 0.03 | |
| ||||||||
2009 | 7.222 | 1358.1 | 1873.35 | 6.6555 | 17.365 | 207.45 | 0.0528 | |
Mean | 2010 | 7.187 | 1422.35 | 1944.08 | 6.644 | 18.072 | 207.7 | 0.055 |
2011 | 7.2545 | 1490.05 | 2007.3 | 6.755 | 18.645 | 216.3 | 0.0578 | |
| ||||||||
2009 | 0.2658 | 453.16 | 574.18 | 1.25741 | 3.9141 | 56.049 | 0.014152 | |
Std. | 2010 | 0.29113 | 455.259 | 570.488 | 1.28389 | 3.987 | 58.448 | 0.01407 |
2011 | 0.284225 | 465.6663 | 581.9234 | 1.268574 | 3.997562 | 58.22199 | 0.014413 | |
| ||||||||
2009 | 3.680421 | 33.3672 | 30.64991 | 18.8928 | 22.54017 | 27.01808 | 26.80303 | |
CV% | 2010 | 4.050786 | 32.00752 | 29.34488 | 19.32405 | 22.06175 | 28.14059 | 25.58182 |
2011 | 3.917913 | 31.25172 | 28.99036 | 18.77978 | 21.4404 | 26.91724 | 24.93599 |
Correlation coefficient (
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 |
Correlation coefficient (
Parameter | pH | EC | TDS | BOD | COD | Na | Pb |
---|---|---|---|---|---|---|---|
2009 postmonsoon | |||||||
| |||||||
pH | 1 | ||||||
EC | 0.3 | 1 | |||||
TDS | 0.412 | 0.975 | 1 | ||||
BOD | 0.348 | 0.88 | 0.899 | 1 | |||
COD | 0.182 | 0.935 | 0.89 | 0.811 | 1 | ||
Na | 0.399 | 0.915 | 0.948 | 0.909 | 0.808 | 1 | |
Pb | 0.084 | 0.832 | 0.78 | 0.676 | 0.827 | 0.748 | 1 |
| |||||||
2010 postmonsoon | |||||||
| |||||||
pH | 1 | ||||||
EC | 0.363 | 1 | |||||
TDS | 0.445 | 0.972 | 1 | ||||
BOD | 0.405 | 0.884 | 0.921 | 1 | |||
COD | 0.244 | 0.933 | 0.893 | 0.829 | 1 | ||
Na | 0.333 | 0.846 | 0.886 | 0.809 | 0.762 | 1 | |
Pb | 0.186 | 0.849 | 0.808 | 0.747 | 0.857 | 0.781 | 1 |
| |||||||
2011 postmonsoon | |||||||
| |||||||
pH | 1 | ||||||
EC | 0.392 | 1 | |||||
TDS | 0.325 | 0.974 | 1 | ||||
BOD | 0.310 | 0.914 | 0.892 | 1 | |||
COD | 0.164 | 0.895 | 0.935 | 0.812 | 1 | ||
Na | 0.363 | 0.879 | 0.843 | 0.818 | 0.730 | 1 | |
Pb | 0.167 | 0.821 | 0.846 | 0.723 | 0.853 | 0.734 | 1 |
(a) Observations of pH in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of pH in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of EC in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of EC in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of TDS in water from the sites SL1–SL10 for the pre- and postmonsoons of 2009–2011. (b) Observations of TDS in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of BOD in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of BOD in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of COD in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of COD in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of Na in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of Na in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011.
(a) Observations of Pb in water from the sites SL1–SL10 for the pre- and postmonsoon of 2009–2011. (b) Observations of Pb in water from the sites SR1–SR10 for the pre- and postmonsoon of 2009–2011.
pH is a measure of the concentration of hydrogen ions (H+) in water. Water with a pH value below 7 is said to be acidic, and water with a pH value above 7 is basic or alkaline in nature [
Electrical conductivity is a measure of concentration of ionized substances that convey electric current in water [
TDS is a measure of the combined concentration of cations and anions [
The BOD values indicate the amount of organic waste present in the water [
The COD level indicates the amount of toxicity in water [
The higher concentration of sodium in the Groundwater causes cardiovascular diseases and toxemia in pregnant women [
Lead (Pb) is a heavy metal gets into the environment through waste water or solid waste disposal. High concentration of lead causes kidney damage, bone damage, and nervous disorder [
The statistical relationship between the water quality parameters was examined, through the analysis of the linear correlation method [
A positive correlation exists when an increase in the value of one parameter is associated with a corresponding increase in the value of another parameter. The correlation matrices for all the samples of three years during pre- and postmonsoon seasons are listed in Tables
Multivariate methods like cluster analysis, factor analysis, principal component analysis, discriminate analysis, neuron net classification, and multiple regression analysis have been successfully used in water quality analysis without much loss of information to a reasonably manageable data set [
The multilinear regression analysis was carried out by using the IBM Statistical Package for Social Science (SPSS) software. The estimated
Regression equations based on analyzed parameters.
Year | Regression equation |
|
|
---|---|---|---|
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 |
The results of the study indicate that the bore wells in the adjoining areas of the Cooum river are highly polluted, and hence the groundwater of the study area is unfit for domestic use. The analysis in respect of seven parameters, namely, pH, EC, TDS, BOD, COD, Na, and Pb, reveals that more than 90% of the water samples have exceeded the drinking water permissible limit prescribed by the WHO, except the pH. The result of the correlation and multilinear regression analysis shows that the conductivity has high significant correlation with the other parameters. The concentrations of EC, TDS, COD, Na and Pb increased every consecutive year, compared to the first year of the study period. This indicates the increase in the pollution load due to the intrusion of domestic sewage and industrial effluents into the Groundwater. Hence, consistent monitoring measures are essential to assess the impact of the percolation of the wastewater, causing contamination of the groundwater in the study area, and a preventive mechanism coupled with remedial measures is necessary for the benefit of mankind.
The authors declare no conflict of interests or financial disclosures relevant to this paper.