当前世界环境

Introduction

水是最重要的大宗商品的测量员ial of life. Earth is regarded as a water planet having about 71% of its suface area covered by water 97.3 percent of worlds water is found in oceans and is salty that cannot be used for agriculture, domestics and industrial purpose. Out of 2.7% fresh water 2.1 percent freshwater is trapped in the polar ice while in the forms of streams, lakes and underground water it is only 0.6 percent. The ground water which occurs upt the depth of 80 meters below the ground surface is predicted to be 8.5 × 10¹⁵m³(Bolenback, 1983; Kataria 1994) According to Shiklomanov (2000) only 0.26 percent of total amount of freshwater on the earth is concentrated in lakes, reservoirs and rivers. In india only 4% of worlds freshwater reserves are available but its population is 16 percent to that of world (Ranjit Kumaret al.,2003).

Bhusawal town is located inKhandeshregion of Maharashtra having the population about 2.5 lakh and the main source of drinking water is Municipal supply and underground water. As a main Railwary junction and improper open drainage system, sewage water accumulates at different areas. As this water can percolate and contaiminate the underground water, we for the first time have carried out the work to study the potability of underground water from different areas of Bhusawal city.

Material and Methods

File liters each of underground borewell water samples form 12 different sampling stations was collected in polyethylene cans and were analysed for total hardness, chlorides, calcium and magnesium, dissolved CO₂解散了啊₂conductivity, TDS contents and COD by the methods as given by APHA (1992).The P^Hand temperature ofthe water was measured at the side of collection and at the same time oxygen was fixed in BOD bottles.

Table - 1: Physico-chemical parameters of borewell water from different locations of Bhusawal city

Except pH, temperature and conductivity all the parameters are expressed in mg/lit

Results and Discussion

The values of different parameters with respect to sampling stations are given in Table -1. The temperature of water was between 23.4 °C to 28.3 °C. The WHO (1992) didnhot recommend any definite temperature for drinking water. P^Hvalue varied between 7.5 to 8.2 as compared to the values of ISI standard. At all sampling stations P^Hwas alkaline while at Sahakar nagar and New RMS colony it was near the highest level. Except V.M. Ward. P^Hvalues at all other stations were above WHO (1992) standards and thus water is slightly alkaline.

的合计al dissolved solids were with in the range of 560 to 2000mg/lit. Except the TDS at V.M. Ward (560), in all samples TDS values were high which is an indication of leading of soluable solids from soil and weathing or rocks (Jhingran, 1988) or due to percolation of water having dissolved solid contents.

的合计al hardness of water a different sampling stations was with in the range of 106 to 192 mg/lit. The levels of hardness are much below the levels (300mg/lit) as laid down by Indian standards and thus the water is soft. The hardness is mainly due to dissolved salts of calcium and magnesium. The comparative values of calcium wre between 48.89 mg/lit to 91.38 mg/lit which were slightly higher than the standard values laid down to WHO (1992) and Indian standards. While the magnesium values ranged between 9.8 to 45mg/lit and at most place values are much lower than the WHO and Indian standards. This range of hardness normally do not have adverse effect on human health. The hardness values above 200mg/lit may cause scale deposition in water distribution system more soap consumption (Trivedi and Goel,1986). The present resluts are comparable to those of Balkrishan and Karuppusmu (2005).

The chloride contents of water was beyond the ISI limit at kazi plot but at all other places are within the prescribed limit (250mg/lit). However, at many places, the chloride contents were near the higher limit. The findings are comparable to the results of Satyanarayan (1992) and Subhadraet al.,(2003).

The conductivity of water at various sampling stations ranged between 600to 1071µ mho/cm and all the stations it was higher than the prescribed limit of WHO (600µ mho/cm) and ISI (750µ mho/cm). It indicates the higher amount of ions in the water that can be due to percolation of sewage water (Thomaset al.,2000) or solubility of salts from rocks.

The DO values of water varied between 0.8 to 4.8 mg/lit. The values were quite low which indicates the possibility of persence of microorgansims in the water. It contrast CO₂values which lies between 11.9 to 28.82 mg/lit are very high. Both aspects indicates that the organisms in water are more. The DO and CO₂values may not play important role in drinking water however, higher CO₂levels makes the water acidic (Jha and Verma 2000). However, though the CO₂levels are high. the P^Hof water was alkaline. The COD values of water were in the range of 3.3 to 20.4 at different locations. The values of COD were very high at New RMS colony and Timber market indicates the percolaton of sewage waterin the underground water.

Acknowledgements

Authors are thankful to Dr. S.P. Zambare, Reader, Department of Zoology. Dr. Babasaheb Ambedkar, Marathwada University, Aurangabad for kind cooperation and valuable guidance during investigation of water analysis.

References