Effect of Textile and Dye Industrial Pollution on Surface Water Quality and Soil Properties in Noyyal River Basin, Tamil Nadu

Contamination of the water resources has increasingly become a serious problem in many of the States including Tamil Nadu due the domestic and industrial waste waters. Only limited studies are available to comprehend the water quality of Noyyal river basin. Hence, this study was undertaken to characterise the quality of surface waters in Noyyal river and its adjoining tanks. The Noyyal river is continuously polluted due to many industries situated on its banks of the river. Textile and dye industries are the major industries that pollute the river. Twenty water samples were collected from various points of rivers and tanks during pre and post monsoon seasons of 2006 to 2007 and analysed for chemical parameters. The E.C. and pH values varied from 0.17 to 8.70 dSm -1 and 5.39 to 8.63 in river water. Cations were in the order of Na>Mg>Ca>K. Around 61.5 per cent of samples found to show RSC values of >2.5 m.e L -1 . SAR/SCAR values indicates that most of the samples (46 %) come under medium sodium class (S 2 ). The EC and pH values of tank water samples varied from 0.41 to 3.13 dSm -1 and 8.0 to 8.5 respectively. Majority of the samples (57 per cent) found to show RSC values of <1.25 m.e L -1 .SAR values indicates that most of the tank water samples (71.4 %) come under Low Sodium Class (S 1 ). Seasonal variations in water quality parameters were also observed in river and tanks.

The Noyyal river has a long and illustrious history as influenced by man, which is indicated by many tanks and canals.Several civilizations have flourished around its banks throughout history (The Hindu, 2003).There are 30 system tanks, 20 channels and two reservoirs in the Noyyal river basin (MSE, 2002).Contamination of the river has increasingly become a serious problem in many of the river basins of the State.River basins like Palar, Tamirabarani, Cauvery, Noyyal, Bhavani and Amaravathy face serious pollution problems due to industrial effluents.(Ministry of Textiles, 2004).In 1989, the Tamil Nadu government issued an order that banned the location of any industrial unit that discharges untreated effluent within one km of the embankment of rivers and reservoirs.The Government has also passed orders imposing total ban of setting up of any of highly polluting new industries within 5 km from the rivers.However, a great many dyeing units lie well within this distance and continue to pollute the river (Sridhar, 2005).
Noyyal river originates from the Vellingiri hills in Western Ghats and passes through the Coimbatore, Erode, Tirupur and Karur districts in Tamil Nadu and confluences with Cauvery at Kodumudi.The flow in the river is seasonal and is contributed by the North East and South West monsoon with an average annual rainfall of about 670 mm.Open wells, dug cum bore wells and bore wells are the groundwater extraction structure in the area.
The textile industry is one of the major industries in India, contributing four per cent to the gross domestic product (GDP), accounting for 20 per cent of the industrial production and 17 per cent of export earning and more than 40 million people are directly or indirectly employed in the textile and clothing sector next to the agriculture sector (Teli, 2008).The major industry in Coimbatore, Erode, Tiruppur and Karur districts of Tamil Nadu are the textile industries.Coimbatore region has been the home of knitwear production since 1925.A regional and agrarian reorganizational process have played vital role in the development of textile industry in this area where majority of the farmers and agricultural workers turned into owners and work force of textile industries (Chari, 2000).
Due to the liberalization of the Indian economy during 1990's, export opportunities were encouraged by the government and within 10 years, Tiruppur became one of the India's major total exporter of hosiery garments (Blomqvist, 1996).Up to 1997, all effluents were diverted into the Noyyal or its tributaries without any treatment (MSE, 2002).Reports show that there were 729 bleaching and dyeing units in Tirupur leaving the effluents of 86 million litres per day (Dorai Kannan and Santhi Kanna, 2008).Other than dyeing and bleaching industries, municipal waste water, soap factories, electroplating industries, foundry units also let down their wastes into the Noyyal river.The pollutant loading will be still higher at present.Common Effluent Treatment Plants (CETPs) were set up during 1997.Individual Effluent Treatment Plants (IETPs) were started after CETP's but there are major problems with their functioning.The industries discharge about 100 million litres per day of effluents, which affect the surface and groundwater quality in the region (MSE, 2002).Most of the studies centered around Orathupalayam dam and Tirupur (Senthilnathan and Azeez, 1999;Kristina Furn. 2004;Nelliayat, 2005, Ramesh Mathan, 2006).Hence, this study focuses on surface water quality of representative areas of Noyyal river basin during pre and post monsoon seasons of 2006 and 2007.

Study area
In Tamil Nadu, there are about 34 river basins, which are grouped into 17 major river basins (ENVIS, 2007).The major and minor rivers flowing in Tamil Nadu are the major source for surface and ground water.The Noyyal river basin is located between latitude of 10º56' and 11º19' N and longitude of 76º41' and 77º56' E. The Noyyal river originates at the Vellingiri hills in Western Ghats and passes through the Coimbatore, Erode, Tirupur and Karur district in Tamil Nadu and confluences with river Cauvery at Kodumudi.It flows over a distance of 170 kilometers with the catchment area of the river is 3510 km 2 (Sankararaaj et al., 2002).
Twenty water samples were collected from various points of rivers and tanks in during pre and post monsoon seasons of 2006 and 2007 and analysed for various chemical parameters.Out of 20 samples 13 points were of rivers and seven were tanks.
The water samples were analysed for quality parameters as per the standard procedure given by Richards (1969).Water quality parameters were classified for the purpose of irrigation as per standard procedures.Residual Sodium Carbonate (RSC) was classified as per Eaton (1950) and Wilcox, et al. (1954).Residual Sodium Bicarbonate was computed and classified based on Gupta and Gupta (1987).Salinity and sodicity classes were assessed as per Richards (1969).The results were also interpreted as per Ayers and Westcot (1994) where the quality of irrigation water interpreted based on the degree of salinity and SAR to judge infiltration problems on soils and toxicity of ions.

EC and Sodium Adsorption Ratio (SAR)
and sodicity classes as per Richards (1969) as follows.

Sodium to calcium activity ratio (SCAR)
Classification of SAR for waters with EC >5 dSm -1 and Mg/Ca >1 is questionable and for higher EC waters, SAR is calculated as Na / Ca 2+ and expressed as sodium to calcium activity ratio would perhaps better correlated with ESP of irrigated soils (Gupta and Gupta, 1987).Critical limits for SAR and SCAR remains the same.

Residual Sodium Carbonate
Residual Sodium Carbonate was calculated as per Eaton (1950) as follows.

Permeability index (PI)
Permeability index or Doneen's Permeability Index was calculated as per Doneen, (1966) as follows.
The index varies with soils having different initial permeability.

Magnesium hazard
Magnesium hazard was calculated by Mg 2+ to Ca 2+ ratio (Richards, 1969).If the value is <1.0, it is classified under non hazardous and the value exceeds 1.0 will cause Mg hazard.

Puri's Salt Index (PSI)
EC and SAR were classified based on salinity Puri (1949) established an index to interpret quality of irrigation water.The value varies from -24.5 to 0 for good waters and 0 to + ve for poor quality waters.PSI = (Total Na + -24.5) -((Total Ca-calcium in CaCO3 ) x 4.85)

Water quality of river water
The E.C. values varied between 0.17 and 8.70 dSm -1 among the river waters (Table 1).The highest EC value was noticed in Anaiplayam near Orathupalayam dam.Majority of the samples (69 %) are coming under very high salinity categories which will pose accumulation of salts in soils on irrigation.The pH values varied from 5.39 to 8.63 in river water.In most of the places the pH was more than 8.0 except in Mathuvarayapuram where acidic pH was noticed.
CO3 2-, HCO3 -, Cl -and SO4 2-were analysed in river water.CO3 2-content in river water ranged from trace to 6.24 m.e L -1 and HCO3 -content ranged from 0.28 to 13.93 m.e L -1 .The highest value of CO3 2-and HCO3 -were noticed at Anaipalayam few kilometers before Orathupalayam.Cl-values ranged from 1.5 to 53.6 m.e L -1 in river waters and the highest Cl -content was noticed at Orathupalayam Dam.SO4 2-content varied from 0.43 to 17.52 m.e L -1 in river waters and the highest was observed at Anaipalayam.Cations were in the order of Na + > Mg 2+ >Ca 2+ >K + .Na concentration varied from 0.94 to 73.48 m.e L -1 in river waters.K + content varied from 0.06 to 2.21 m.e L -1 in river waters.Ca 2+ and Mg 2+ concentration varied from 0.7 to 5.25 m.e L -1 and 0.51 to 8.4 m.e L -1 , respectively.The highest value of Na + , Ca 2+ , Mg 2+ were noticed at Anaipalayam, Tiruppur and Orathupalayam dam, respectively.

Classification of river waters for irrigation purpose
The results indicated that the values of RSC varies from -2.3 to 8.4 m.e L -1 and RSBC varies from -0.4 to 8.9 m.e L -1 .Majority of the samples (61.5 per cent) found to show RSC values of >2.5 m.e L -1 which suggest that these waters will pose considerable influence on soil properties on irrigation and 54 per cent of samples exhibit moderate problem on soil with respect to RSBC values (5-10 m.e L -1 ).
Presence of Na + salts and their concentration in water decide the quality of irrigation water.The classification of irrigation water with respect to SAR is based on the abundance of exchangeable Na + particularly on the physical condition of the soils.Waters with EC >5 dSm -1 and Mg/Ca >1 are classified based on sodium to calcium activity ratio (SCAR) as per Gupta and Gupta, (1987)  Seasonal change was clearly noticed in river samples (Fig. 2).In most of the samples, the EC was high during August followed by April.Normally instead of SAR.The limits are same, for both SAR and SCAR.SAR or SCAR values indicates that most of the samples (46 %) come under Medium sodium class (S2) followed by Low sodium class (S1) with 38.5 per cent and 15.0 per cent come under High sodium class (S3).High sodium class water will exhibit sodicity in soils on irrigation.

Fig. 2 .
Fig. 2. Seasonal change in EC, RSC and SAR/SCAR in Noyyal river and tank water