Study of physicochemical quality of pond water in Bilaspur, Chhattisgarh

Physico-chemical quality of water samples form four major ponds, i

Torwa (S2); pond near Family Planning center, Sarkanda (S3); and pond near Devnandannagar (S4) on monthly basis over a period of one year i.e. 2007.These ponds are situated in populated areas of the city and water from these ponds is used for various human activities except drinking.Therefore it becomes very important to assess periodically the quality of water from these water bodies to ascertain their pollution load.

EXPERIMENTAL
For the present study, four major water pons of Bilaspur were selected.All these four ponds receive rain water and domestic waste water from nearby settlements.These domestic waste and rain water make these ponds highly polluted.There are a few water hand pumps set in close vicinity of these ponds and water from these hand pumps is being used by people residing in those areas even for drinking purpose and they are pond to water related ailments.Therefore it was interesting to assess the extent of pollution load on these ponds.For the same, water samples were collected in the first week of every month during the study period and the parameters like pH, Electrical Conductivity, Temperature, Dissolved Oxygen were determined on the collection site itself using Elico make PE-136 Water and Soil Analysis kit.Other parameters like BOD, COD, Total Solids, Total Dissolved Solids, Total Suspended Solid, Sulphate, Nitrate, Chloride, Fluoride and Phosphate were also determined using standard methods recommended by APHA 9 and NEERI 10 .All the chemicals used during present investigations were of analytical grade and double distilled water from all glass was used during present study.The results obtained from these analyses were statistically treated to calculate correlation between various parameters of study.

RESULTS AND DISCUSSION
Results of analyses of water from these ponds are recorded in tables 1 to 4 and correlation between various physico chemical parameters thus calculated area given in table 5 to 8. A persual of tables 1-4 indicates that the pH of the water from all the sampling stations ranged between 8.43 (at pond near family Planning Center in the month of July 2007) and 7.02 (at pond near Devnandan Nagar in the month of January-2007).This was well within the maximum permissible limit for pH, as recommended by WHO* (6.9-9.2).Electrical conductivity of water samples, which is a measure of presence of ionic constituents, was found maximum at Devnandan Nagar pond and at Depot Para pond in the month of March-07 (680µmhos/cm).This was much above the maximum permissible limit of 500 µmhos/cm as recommended by WHO.
Turbidity in water samples is due to suspended solids present in them and is a primary indication of the extent of pollution As per WHO recommendation 25 NTU is the maximum permissible limit for turbidity in drinking waters.All the water samples were found to contain this exceeding the maximum permissible limit.Solids, suspended and dissolved, if present in large amounts may affect water quality as it may induce unfavorable physiological reactions in the transient consumer.WHO has 500 mg/l as maximum tolerance limit for this¹¹.Among the collected water samples, the samples form Depot Para pond were found to contain maximum solid contents i.e.559 mg/l.Dissolved Oxygen in water samples is an important parameters as this is indicative of desirable conditions for favorable growth and reproduction of auqatic organisms.This condition requires the maintenance of dissolved oxygen levels that can support the desired auqatic life in healthy conditions.During study period maximum DO levels (6.9 mg/l) were found in the water from pond near Devnandan Nagar in the month of April-2007.BOD of water samples is essentially a bioassay method which is indicative of pollution load on the water body.USPHS (United States Public Health Service) and WHO¹¹.Both have proposed a maximum permissible limit of 5mg/l for BOD.During the present study BOD levels in most of the samples were much more beyond the permissible limit and at many places it was as high as>7.In the month of May 2007, in the samples from pond near Depot Para, BOD was recorded as high as 10mg/l.This clearly showed that these ponds are bearing appreciable high load of bio degradable organic pollutants.COD measurements give us an indication of total organic matter (both biologically oxidisable and inert) in the water.A threshold value of 4mg/l has been proposed by USPHS¹².A persual of all the tables revealed that COD levels in all the water samples and during entire study period was much above this limit.Maximum value of 144mg/l was recorded at Depot Para pond in the month of June 2007.On the other hand minimum value of 28mg/l was found at Family Planning center pond in the month of March-2007.Fluoride in water samples is the cause of fluorosis and dental caries.Safe limit for fluoride in drinking water is as per WHO recommendations is in between .1 and 1.5mg/l¹¹.In all the four ponds fluoride levels were below this 1.5 mg/l mark.Nitrate is a key issue in the drinking water as its level in ground water have shown alarming increase during past two/three decades due to extensive use of nitrogenous fertilizers.Due to increase in nitrate levels in water bodies, nutrient enrichment also occurs and this ultimately          During the study period correlation analysis was conducted and perusal of tables 5-8 shows that strong positive correlations existed between turbidity -TDS, TS-TDS, Chloride-Fluoride at pond near Depot Para.On the other hand strong negative correlations were recorded at the same pond between DO-TDS, DO-TS and nitrate-chloride.Strong positive correlations were observed in the water from pond near old power house between pH-turbidity, ph-TSS, and pH-Chloride, BODturbidity, TS-TDS, TH-Ca-H, TH-chloride.At pond near Family Planning Center pH was found to correlation existed between nitrate and COD.Strong positive correlations were existed in the water from pond near Devnandan Nagar between EC and COD, TS and TDS, DO and COD, Ca-H and TH.

CONCLUSION
The present study indicated that the waters from the four major ponds situated in Bilaspur were quite heavily polluted particularly with organic pollutants and the water from these ponds is very unsafe and must be used only after suitable treatment process.

Table 1 :
Physico chemical characteristics of water samples from pond near Depot Para, Bilaspur during Year