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Effects of idol immersion on the water quality parameters of Indian water bodies: Environmental health perspectives

India is a rich cultural country in which diverse cultural and religious festivals are organized. Idol is an image of a god which is used as an object of worship. After worshipped, these idols are immersed into water bodies. Idols are constructed by plaster of paris, clay, cloths, small iron rods, bamboo and decorated with different paints such as varnish, water colors etc. which can lead to significant alteration in the water quality after immersion. Paints which are used to colour these idols contains various heavy metals such as Mercury, Cadmium, Arsenic, Zinc, Chromium and Lead. Particularly, red, blue, orange and green colours contain mercury, zinc oxide, chromium and lead, which are potent carcinogens. Two heavy metals such as Lead and Chromium also add in the water bodies through Sindoor (a traditional red colored cosmetic powder, usually worn by married women and often used in the festivals). The floating materials released through idol in the river and lake after decomposition result in eutrophication, increase in acidity and heavy metal concentration. Heavy metal pollution caused by idol immersion can damage the ecosystem as it kills fishes, damages plants, blocks the natural flow of the water, causing stagnation. The effects of idol immersion on various water bodies of India like Bhoj wetland, Budhabalanga river, Ganges river, Hussainsagar lake, Kolar river, Sarayu river, Tapi river, Chhatri lake, north and west lakes of Bangalore and Yamuna river have been observed so far. Investigations were carried out to find out the effects of immersion of idols on water quality by collecting and analyzing the water samples from the immersion sites of the rivers. The samplings were done before the immersion, on the day of immersion and after the event and several parameters like Temperature, pH, Dissolved Oxygen, BOD, Dissolved CO2, Conductivity, Salinity, Alkalinity, TDS, Total Hardness, Chlorides etc. are estimated. Most of the studies found significant changes in the water quality parameters during and after immersions. Central Pollution Control Board has formulated guidelines on the practice of idol immersion in water bodies, which should be followed for controlling pollution.


INTRODUCTION
India is a rich cultural country in which diverse cultural and religious festivals are organized. Idol is an image or other material object representing a deity to which religious

EFFECTS OF IDOL IMMERSION ON THE WATER QUALITY OF INDIAN RIVERS AND LAKES
Water pollution occurs due to the discharge of municipal sewage both domestic and industrial without any treatment which brings considerable changes in the river water quality in addition to many religious activities now became a threat to the ecosystem [20,21].
Traditionally, idol immersion activities are going on in our country. After idol immersion, materials which are used in idol making that do not dissolve easily in water, thereby reducing the oxygen level and psychochemical characters are become changed in the water bodies. The changes in the water quality parameters in the major water bodies in India due to idol immersion are discussed below:

1. Saryu River
The Saryu River flows through the Indian states of Uttarakhand and Uttar Pradesh. The Sarayu forms at the confluence of the Karnali (or Ghaghara) and Mahakali (or Sharda) in Bahraich District [22]. The immersion of idols of Lord Ganesh and Durga during Ganesh Ustav and Navratris festivals is a major source of contamination and sedimentation to the river. The festivals of Ganesha Chaturthi and Durga Puja witness a massive community involvement. To match the contemporary ethos, new materials are being used for modernising the representation of these idols without much thought being given to the issue of toxicity and its impact on the environment [23].
Most of freshwater bodies all over the world are becoming polluted, thus decreasing the portability of the water. An investigation was carried out to find out the effects of immersion of idols on water quality of the river by collecting and analysing the water samples from the immersion site of the river. The sampling was done one week before the immersion, on the day of immersion and after ten days of the event [26]. After analysing the river water samples, it was found that before the immersion of idols the dissolved oxygen level was 15 mg/l which decreased during immersion (10 mg/l) and after the immersion activity, D.O was 11 mg/l. BOD was observed (9 mg/l) before immersion, maximum during (14 mg/l) immersion and after (11 mg/l) the immersion activity.
The average values of DO and BOD indicate the presence of organic pollution sources [23]. Earlier studies reported the high values between 23.0-56.4 mg/l and indicated the high organic pollution in river [28]. The hardness of water is not a pollution parameter but indicates water quality. The BIS recommend the limit of total hardness for drinking water purpose to be 300 mg/l and WHO has set 100 mg/l. Hardness was reported between 94.0 and 167.3 mg/l in Hanuman Taal, Jabalpur [29]. The results of total hardness were 35 mg/l (before immersion), 41 mg/l (during immersion) and 50 mg/l (after immersion). Turbidity was recorded 30 NTU, 60 NTU and 55 NTU during the three stages of the activity respectively [23]. The water column is disturbed completely during idol immersion causing higher turbidity [3].
Though magnesium is non-poisonous, it increases the hardness of water. The concentration of Calcium, Magnesium, and Cadmium in the river water was 38.14 mg/l, 8.78 mg/l, 0.003 mg/l before the immersion which increased to 51.57mg/l, 11.58 mg/l, 0.012 mg/l during the immersion and was 60.93 mg/l, 15.75 mg/l, 0.03 after the immersion respectively. Manganese, Lead, Iron, Mercury were found 0.091 mg/l , 0.192 mg/l,0.123 mg/l, 0.575 mg/l before the immersion and 0.182 mg/l, 0.219 mg/l, 0.311 mg/l, 0.617 during immersion and 0.299 mg/l, 0.411 mg/l, 0.521 mg/l, 0.811 after the immersion [23].
So, the findings of the study revealed that the water quality degraded after the immersion of idols as some of the parameters were above the permissible limit and also reveals a clear picture of the status of water quality at different stages which shows in Figure  5. The higher concentration of some parameters is probably due to heavy pollution load due to the immersions, resulting in the deterioration of the natural water body. Therefore, it is suggested that the authorities should conduct environmental awareness programmes, particularly before the festival to educate the public of the city and make them aware of the harmful environmental effects of immersion of idols. By doing that pollution can be reduce [23].
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2. Kolar River
The Kolar River (Kolhar River) is a river of Nagpur district, Maharashtra, India, flowing southeast from above the town of Saoner to its juncture with the Kanhan River. It is in the Godavari river basin [32]. In Kolar River, after Ganesh and Durga puja thousands of idols were immersed. An investigation was carried out to find the changes of some water quality parameters, after idol immersion in Kolar river. For this investigation two sampling stations have been selected. Station 1 was near Shiv Temple, Pahlepar and station 2 was near Borujwada, Saoner.

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Samples were collected and preserved from both the stations as per standard methods. Samples were collected during idol immersion successive three days of immersion activities from both the stations. pH of river at two stations were found to be 8.6 and 8.3 respectively.
In present study, water temperature, T.D.S, Total alkalinity, Total hardness, D.O, BOD, COD, Nitrates, Phosphates, Oil and Grease, Total calcium were found to be 30 and 29, 324 mg/l and 31 6mg/l, 176 mg/l and 168 mg/l, 177 mg/l and 159 mg/l, 2.4 mg/l and 2.6 mg/l, 4.1 mg/l and 4.4 mg/l, 59.14 and 54.12, 0.025 mg/l and 0.019 mg/l, 0.043 mg/l and 0.040 mg/l, 0.54 and 0.49, 132 mg/l and 129 mg/l station wise respectively ( Figure 6). The present study on assessment of idol immersion on water quality of Kolar river shows that the idol immersion has negative impact on physical and chemical properties of water.

3. Budhabalanga river
Budhabalanga River is a river of Eastern India and North east Odisha with a length around 175 km. This river plays important and major role in economic and social growth and development in Balasore. The people of Balasore are always excided for celebration of festivals. The immersion of idol of Lord Ganesh (Figure 7), Lord Viswakarma and Goddess Durga during month of August to October is a major source of contamination and sedimentation to the River Budhabalanga. About 500 or more Ganesh idols and about 150 Durga idols were immersed during 2011 in Balighat immersion point. Balighat point was selected as sampling station [37]. Water samples were collected at morning hours a week before of immersion, during immersion and ten days after immersion. After analysing the river water samples, it was found that Calcium, Magnesium, Cadmium, Chromium, Mercury, Manganese, Lead, Iron and Arsenic were 24.05 mg/l, 17.56 mg/l, 0.019 mg/l,0.018 mg/l, 0.058 mg/l, 0.2 mg/l, 0.13 mg/l, 0.87 mg/l, 0.124 mg/l respectively before the immersion and during immersion 56.11 mg/l, 21.70 mg/l, 0.024 mg/l, 0.020 mg/l, 0.0592 mg/l, 0.44 mg/l, 0.25 mg/l, 1.35 mg/l, 0.169 mg/l respectively. After 10 days of idol immersion Ca, Mg, Cd, Cr, Hg, Mn, Pb, Fe, As were found 68.16 mg/l, 35.18 International Letters of Chemistry, Physics and Astronomy Vol. 39 mg/l, 0.036 mg/l, 0.029 mg/l, 0.067 mg/l, 0.65 mg/l, 0.291 mg/l, 1.75 mg/l, 0.173 respectively and 45 days of idol immersion 35.27 mg/l, 19.71 mg/l, 0.022 mg/l, 0.019 mg/l, 0.059 mg/l, 0.23 mg/l, 0.205 mg/l, 0.94 mg/l, 0.134 mg/l respectively. These data revealed that the water of River Budhabalanga is deteriorated due to the immersion of different idols [37]. The study also made a clear picture of the status of water quality at different stages in Budhabalanga River, which shows in Figure 8.

Ganga river
The Ganges or Ganga is a 2525 km. long trans-boundary river of Asia which flows through India and Bangladesh that empties into the Bay of Bengal and it is the third largest river by discharge [38]. The Ganges was ranked as the fifth most polluted river of the world in 2007. Pollution threatens not only humans, but also more than 140 fish species, 90 amphibian species and the endangered Ganges river dolphin [39]. The Ganga Action Plan, an environmental initiative to clean up the river and for the proper management of water pollution [40,41].
After worshipped, a huge number of Jagadhatri idols are immersed every year in the holy river Ganga at Ranighat, Chandernagore, West Bengal. A study highlighted the water quality status in Ganga river during Jagadhatri festival. The study mainly emphasized on the changes of water quality parameters during pre-immersion, immersion and post-immersion periods of idols into the river Ganga. After idol immersion the temperature of river water was 33.0 °C recorded during pre-immersion period, 30.4 during immersion and 31.2 °C in postimmersion periods. After idol immersion, pH ranges between 7.26 (pre-immersion) to 7.91(during immersion) and after immersion pH was 7.65 [42]. From the study, Transparency and Conductivity was found 32.90cm and 210.30 μS/cm respectively before immersion. During immersion and after immersion Transparency and Conductivity was 14.57cm, 283.96 μS/cm and 21.30cm, 265.48 μS/cm respectively. DO, BOD, COD, Total alkalinity, Chloride, Total hardness, Phosphate were found 5.67 mg/l, 2.25 mg/l, 11.10 mg/l, 95.67 mg/l, 14.77 mg/l, 116.33 mg/l, 0.38 mg/l respectively before the immersion and 8.29 mg/l, 3.41 mg/l,

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ILCPA Volume 39 21.77 mg/l, 167.24 mg/l, 47.77 mg/l, 136.74 mg/l, 0.94 mg/l respectively found during immersion and 6.17 mg/l, 3.18 mg/l, 17.91 mg/l, 133.01 mg/l, 25.06 mg/l, 123.27 mg/l, 0.78 mg/l respectively found after immersion of idols. From the investigation it was cleared that in Ganga river, there was marked variations in different parameters which shows in Figure 9.
And also it was found that the values of these parameters significantly increased during the period of immersion and declined in the post-immersion period [42].

5. Hussainsagar Lake
Hussain Sagar, is a lake in Hyderabad, Andhra Pradesh, India, built by Hazrat Hussain Shah Wali in 1562, which spread across an area of 5.7 square kilometers and this lake was the main source of water supply to Hyderabad [44]. The lake is constructed across Kalvaleru stream, one of the tributaries of Musi River passing through Hyderabad city. It is 3.2 km long and 2.8 km wide and its depth ranging from 2.5 to 12.5 m with a surface area of 446 hectares. Thousands of Ganesh idols of various sizes reaching heights up to 45 to 50 feet and goddess Durga are also immersed in the Hussainsagar Lake [2]. In 2001, an investigation carried out to find out the effects of immersion of Ganesh idols on water quality of Hussainsagar lake, by collecting and analysing the water samples from the immersion sites of the lake before and after ten days of immersion activities, following the standard methods [45]. After analysing the river eater samples, it was found before the immersion of idols Calcium, Magnesium, Molybdenum and silicon were 6.590 mg/l, 0.149 mg/l and 2.954 mg/l respectively which increased after the immersion activity 68.4 mg/l, 10.02 mg/l, 0.354 mg/l and 3.826 mg/l respectively. Over the years, the average concentration of heavy metals, especially arsenic, lead and mercury has also increased considerably in the lake water. The concentration of arsenic which is a noxious trace element, has increased nine-fold, lead and mercury which are potentially obnoxious heavy metals, had increased many-fold in the lake water after the idol immersion. After the immersion of the idols, mercury concentration increased further, to more than seven-hundred fifty times in the water. So, the investigation reveals that a huge changes in water quality in Hussainsagar lake after idol immersion which shows in Figure 10  Lake water before and after the immersion of Ganesh idols. Figure 11. Shows Physicochemical analysis of water before and after Idol Immersion in Chhatri lake.

6. Chhatri Lake
Chhatri Lake located outskirt of Amravati city, Maharashtra. In every year, after Ganesh and Durga Utsav, 3000-5000 idols of Lord Ganesh of various shapes and sizes were immersed in Chhatri Lake. Due to these religious activities, the physiochemical characteristics of water quality of Chhatri lake was changed. The present investigation study was the basis of data collected before and after immersion of idols in August 2009 Ganesh festival.
Analysis of composite water sample of Chhatri Lake shows that the water quality parameters are Temperature, pH, Dissolved Oxygen, BOD, Dissolved CO 2 , Conductivity,

7. Yamuna River
The Yamuna, sometimes called Jamuna, is the largest tributary river of the Ganges (Ganga) in northern India [47]. Total length of the River Yamuna from its origin near Yamunotri Glacier at a height of 6,387 metres to its confluence with Ganga River at Allahabad is 1376 kilometre [48]. The total basin area of the river is 366223 km 2 which covers part of geographical area in the states of Uttaranchal, Uttar Pradesh, Himachal Pradesh, Haryana, Rajasthan, Madhya Pradesh & NCT -Delhi [49]. The 22 km stretch in Delhi, once described as the life line of the city, today has become one of the dirtiest rivers in the country [50]. River Yamuna, the main source of water supply to national capital-Delhi, plays a crucial role in its growth [51]. Idol immersion is one cause of water pollution in the river Yamuna as it is widely worshipped by devotees in India. The immersion of idol of Lord Durga during Navratris festival is a major source of contamination and sedimentation to the lake water. During the immersion ceremony, puja articles such as polythene bags, foam cutouts, flowers, food offerings, decorations, metal polish, plastic sheets, cosmetic items, all of which are highly polluting, are also thrown into the water. A study was carried out for assessment of water quality of River Yamuna after idol immersion. The sampling was done in three phases; pre idol immersion sampling, during idol immersion and post immersion sampling. The samples were collected from 13 different locations such as Thokar No. 8, Thokar No. 12, Ram Ghat u/s of Wazirabad, Sonia Vihar U/S of Wazirabad, D/S of Wazirabad, Garhi Mandoo, Majnu Ka Tila, Khudesia Ghat, Geeta Colony, Haathi Ghat, Nizamuddin , Kalindi kunj and Okhla Barrage of the Yamuna along the Delhi stretch, primary sites for practicing idol immersion. The composed data was analyzed for the year 2011, to understand deterioration in the water quality of the river due to idol immersion practices. From the analysis, it was found that among from all sampling station, minimum concentration ( Figure 12) of some chemical parameters such as pH, BOD, COD, Total Suspended Solids (TSS) were 6.9, 1.4 mg/l, 16 mg/l, 294 mg/l respectively before the immersion and during immersion 7.3, 4.0 mg/l, 32 mg/l, 494 mg/l respectively and after immersion 7.3, 3.3 mg/l, 28 mg/l, 430 mg/l respectively. Also it was found that among from all sampling station, maximum concentration ( Figure 13) of some chemical parameters such as pH, BOD, COD, Total Suspended Solids (TSS) were 7.8, 35 mg/l, 124 mg/l, 1366 mg/l respectively before the immersion and during immersion 7.9, 55.0 mg/l, 188 mg/l, 1264 mg/l and after immersion of idols all chemical parameters were becomes 7.9, 38.0 mg/l, 136 mg/l, 1268 mg/l respectively.

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The low levels of DO and high BOD and Total solids levels at different sites indicate the poor water quality due to idol immersion [48].

8. Marine (Shivaji Park or Dadar Chowpatty beach) and fresh water bodies (Masunda lake)
Shivaji Park or Dadar Chowpatty beach is located in Mumbai, India. The beach is mainly used for walking and jogging purpose but is unfit for bathing as the faecal coliform concentration & BOD values are 6-8 times higher than the permissible levels. On designated days of immersion, devotees assemble to immersion spots at Shivaji Park and have to wait for 246 ILCPA Volume 39 long hours for immersion of Ganesha idols. Due to heavy immersions in its water, the condition of Dadar beach has further deteriorated. Masunda lake also called as Talao Pali is one of the prominent lakes in the heart of Thane city. The lake is mainly used for fishing & boating and also serves as a tourist spot. Every year thousands of Ganesha devotees gather on the lake to perform Visarjan ceremony on 2nd, 5 th & 11th day of Ganapati festival. Idol immersion activities have deteriorated the water quality and negatively affected the recreational activities in the lake.
Idol immersion activities during certain festive occasions are adding to the pollution load of the Marine and Fresh water-bodies. The present work is concern about the water quality assessment to evaluate the nature and the extent of pollution in marine and fresh water body. For this purpose, two prominent idol immersing sites in Mumbai: one marine-Sea at Shivaji Park or Dadar beach and other freshwater-Masunda lake, Thane were selected as sampling site. Water samples were collected a week before of immersion, during immersion and three weeks after the completion of immersion activities and analyzed for various water quality parameters. From the assessment it was found that in Fresh water samples pH, TSS were 7.8, 13mg/l in pre immersion, 7.

9. Lakes of Bangalore
Bangalore city is located at Latitude of 12.58° North and Longitude of 77.36°. The mean annual temperature being 24 °C with extremes ranging from 15 °C in winter to 37 °C in summer. The average annual rainfall is 900 millimetres. Bangalore, the capital city of the southern Indian State of Karnataka is the third largest city in India. The biological wealth of a lake is mainly dependent on its water quality.
This study highlights the quality of water analysed with reference to various physicochemical parameters in selected lakes of Bengaluru North, of Karnataka state before and after the immersion of Ganesha idols. These selected lakes are Yelahanka lake, Dasarahalli lake, Machohalli lake, Gangodanahalli lake, Herohalli lake, Mallathali lake, Ullala lake and Komagatta lake.
Where, thousands of painted Ganesha idol were immersed in a day, estimated that more than a lakh idols were immersed in a week per lake. The major ions present in the lake water have been analysed. The lakes are found to be under the influence of parameters like turbidity, temperature, pH, chloride, Total dissolved solids (TDS), total hardness, alkalinity, potassium, sodium, calcium and magnesium [53].

10. Upper and lower lakes of Bhopal
Upper lake situated in Bhopal is arguably the oldest man-made lake in India, and was created by Raja Bhoj in the 10th century AD by constructing an earthen dam across the Kolans River. The Upper lake (Lat 23°16'N and Long 77°18' -77°23' E, with a catchment area of 361 sq. km. and presently having a water spread area of 31 sq.km.)has many direct and indirect uses [4]. The Lower lake (Lat 23°16' N and long 72 0 25' E) situated in Bhopal is an artificial lake created in 1794 AD. Lower lake situated towards the east end of the Upper lake and is an integral part of the latter. Lower lake has a small catchment area of 9.60 sq. km and water spread of 1.29 sq.km [54].
This upper lake of Bhoj wetland is a major source of potable water, a recreational hubwith boating, a cruise ship, walkways, restaurants, a tourist destination, a bird habitat and a Ramsar Site, a source of livelihood (fishing, boating, chestnut farming etc), a cultural landmark and a micro-climatic influence on the city. The upper lake is one of the most productive and resourceful, with a wide range of economic social and ecological benefits. Idol immersion is one of the pressures the wetland is facing during the festival seasons [4]. The quality of water in Lower Lake has far more deteriorated than that in the Upper Lake due io idol immersion activities [55].
The Lower Lake receives a large amount of raw sewage from its densely populated habitation. The water body is an urban eutrophic lake where the amount of nutrient is very high and O 2 depletion is very prominent [56].
In 2012, an investigation was carried out by Bhat et. al , to find the physico-chemical changes in water quality after idol immersion in upper lake Bhoj wetland. The physicochemical parameters of water quality were analysed. Prempura Ghat and Sheetal Das ki Bagiya are selected as sampling station because maximum immersions take place in this station.
BOD was found in the range of 5 -15 mg/l. in pre, while 8 -26 mg/l. and 12.2-39 mg/l. during and post samples respectively for both the Stations. During the study higher values that cross the permissible limits. COD was found in the range of 42 -65 mg/l. in pre, while 55-92 mg/l. and 62 -115mg/l during and post samples at both the station. Maximum limit for drinking water is 150 mg/l [58].Oil and grease was noticed comparatively higher in during and post period at the station S-1 [54].
In 2007, Vyas et. al. was done an another research work on heavy metal contamination cause of idol immersion activities in urban lake Bhopal, India. For this purpose, Samplings was done from three sites of Upper lake.
The water samples were collected from surface layer and the site of idol immersion at different intervals a week before of immersion, during immersion and 15 days after of post immersion. The samples were subjected to analysis heavy metals. It was observed that before the idol immersion the concentration of calcium, magnesium, cadmium and chromium were found 39.64 mg/l, 9.98 mg/l, 0.003 mg/l and 0.009 mg/l respectively.
During immersion activities and post immersion calcium, magnesium, cadmium and chromium were found 53.21 mg/l, 12.34 mg/l. 0.013 mg/l, 0.015 mg/l and 66.97 mg/l, 16.52 mg/l, 0.021 mg/l, 0.028 respectively. It was also found that before the immersion of idol, Manganese, Lead, Arsenic and Mercury were 0.084 mg/l, 0.243 mg/l, 0.132 mg/l and 0.689 mg/l respectively. During immersion Manganese, Lead, Arsenic , Mercury were found Manganese, Lead, Arsenic and Mercury were 0.146 mg/l, 0.364 mg/l, 0.125 mg/l, .552 mg/l respectively and after the immersion period 0.328 mg/l, 0.609 mg/l, 0.145 mg/l, 0.954 respectively ( Figure 26) [59]. From all the research, effect on upper and lower lake of Bhopal by different scientist which are mentioned above, revealed that idol immersion activities have negative effect on water quality of lakes. From the results of water samples study also it was found that the water quality of lake was not suitable for the drinking [4].

11. Tapi River
Surat is situated on the bank of Tapi River that plays important and crucial role in its economic growth and development. Tapi River is a river of western India. It is one of the major rivers of west coast river system of India with a length around 724 km. Tapi river originates from the Satpura range of hills, Betul district of Madhya Pradesh. The flow of Tapi River covers Maharashtra, Madhya Pradesh and Gujarat state and empty into the Arabian Sea. The people of Surat city are always excited for celebration of festivals. Ganesh Chaturathy is one of the important festivals of them [21]. In this festival number of Ganesh idols in different sizes are immersed in Tapi River after worship of 10 days. In Tapi river, about 2700 idols were immersed during 2010 [60].
In 2011,a study has been done by Ujjania and Multani, to found the impact of Ganesh idol immersion on water quality of Tapi River. For this purpose Ashwanikumar immersion point (Ovara) was selected as sampling station because large number of Ganesh idols immersed on this Ghat of Tapi River. Water samples were collected at morning hours during pre immersion, during immersion and post immersion periods of Ganesh idols. After analysis of samples, it was observed that after idol immersion, Temperature of the river water was 29.8-30.5 °C. But 29.0-31.0 °C, 28.0-31.0 °C recorded during immersion and pre-immersion respectively. The minimum pH (6.9) was observed at pre-immersion while acidic pH (7.6) was observed during immersion period of idols.
The free CO 2 released by microbial activity is important for algal growth, as it is required for the photosynthesis. Low free CO 2 (17.2 mg/L and 17.6 mg/L) was found during pre immersion and post immersion period while high free CO 2 (18.8 mg/L) was found during immersion period. Before immersion of idols D.O, BOD and COD of river water was observed 6.4-6.8 mg/L, 3. Before immersion of idol the oil and grease content found in the river water was 0.43-0.69 mg/L. But 0.9-1.3 mg/L and 0.7-0.8 mg/L was recorded during immersion and post immersion respectively [21]. In 2012, Ujjania and Mistry have done a research work to present the environmental impact of Ganesh idol immersion on water quality of Tapi River. For this purpose Pal idol immersion point (Ovara) was selected for sampling purpose because this is one of the important idol immersion point of Tapi River. Water samples were collected in morning at different intervals like pre-immersion, immersion and post-immersion. These samples were subjected to analyze the physico-chemical parameters. The environmental impact of Ganesh idol immersion activity on water quality of Tapi River was assessed and significant changes in physico-chemical properties of water were observed. In the present study pH, temperature, DO, free CO 2 , Total hardness, total alkalinity, BOD, COD, oil and grease and total calcium were varied from 6.9 -7.  [61].
In 2010, Desai and Tank was carried out a investigation to study deterioration of water quality of River Tapi at Surat. Sampling was done from two sites of river namely Navdi Ovara and Ramnath Ghela [62]. According to officials of civic body like Surat Municipal Corporation (SMC), nearly 20000 to 25000 idols of various sizes are immersed in the river [63]. The water samples were collected from the site of idol immersion at different intervals a day before immersion, during-immersion and a day after immersion. From the river water samples analysis, it was found that before idol immersion P H , Temperature, Total hardness, Conductivity, Alkalinity, DO, BOD, COD, TDS, Lead and zinc were 8.5, 28.5 °C, 188 mg/l, 514μmho/cm, 8mg/l, 405 mg/l, 600 mg/l, 2165.12 mg/l, 360 mg/l, 0.153 mg/l and 0.043 mg/l respectively for both sites.
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DISCUSSIONS AND CONCLUSIONS
In this paper, changes of physio-chemical characteristics after idol immersion on different water bodies are discussed. This discussion make a clear picture is that idol immersion activity has negative impact on water quality of all water bodies. The main reason of the deterioration of water quality in different water bodies is various religious activities such as idol immersion. Traditionally, year by year, this idol immersion activities going on. From the mythological point of view, the water bodies are related to religious sentiments but from the scientific point of view, these water bodies like ponds, lakes and rivers are not suitable for human uses [21]. After idol immersion, the water bodies were polluted especially with heavy metals. It is worrisome because due to deterioration of potable water, these water resources is harmful for domestic and drinking purpose. The cumulative effect of this usage can be disastrous because many of these metals are poisonous. During the Hindu festive season, hundreds of idols of God and Goddess are immersed in the different water bodies.

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The possible ways of dealing with this grave problem is by creating awareness among the masses. The lack of awareness among our people is the main reason behind such an environmental pollution. Environmental awareness campaigns and meetings should be organized to make public aware of environmental damage caused due to immersion of idols into the river system. Different communication media may serve as a useful tool for such a campaign. A Co-ordinated Committee comprising Police, Non-Government Organization, Local Authorities, State Pollution Control Boards, representatives of puja committees and stakeholders should be set up for guiding the public in carrying out the immersion with minimal impact on water bodies [48]. Central Pollution Control Board has formulated a comprehensive set of guidelines on the practice of idol immersion in lakes, rivers and seas [64]. According to CPCB, general guideline for idol immersion mentioned below.
 Idols should be made from natural materials as described in the holy scripts. Use of traditional clay for idol making rather than baked clay, plaster of paris, etc. may be encouraged, allowed and promoted.  Painting of Idols should be discouraged. In case idols are to be painted, water soluble and nontoxic natural dyes should be used. Use of toxic and nonbiodegradable chemical dyes for painting idols should be strictly prohibited.  Worship material like flowers, vastras (clothes), decorating material (made of paper and plastic) etc. should be removed before immersion of idols. Biodegradable materials should be collected separately for recycling or composting. Nonbiodegradable materials should be collected separately for disposal in sanitary landfills. Clothes may be sent to local orphan house(s).  Public should be educated on ill effects of immersion in the holy water bodies through mass awareness programme.  The 'Idol Immersion Points' shall be cordoned and barricaded. Synthetic liner may be placed in the bottom, well in advance. The said liner shall be removed on completion of immersion ceremony so that remains of idols would be brought to the bank. Bamboo and wooden logs, if any would be reused. Clay, etc may be taken to sanitary land fill for disposal [64].
These guidelines if followed and acted upon can help in bringing tremendous change in the water quality of water bodies post idol immersion. Debris flowing through in water bodies can be collected and treated with technical measures that can prevent the further deterioration of the river during immersion period [48]. Some other alternatives should be taken for reducing the water pollution. These alternatives are mentioned below.
 Immersing the idols in a water tank or in a bucket of water at home.  Avoid the use of different decorative material (Thermocol sheets, polythene bags, etc.)  Selective plantation may do at the immersion site because some has an ability to absorb heavy metals.  Use of a permanent icons made of stones and brass, used every year [46].
Even though some cities have now provided water tanks for Ganesh immersion, they still need to ensure that the water in these tanks is properly treated before it is put back into rivers or the sea. Plaster of Paris idols with chemical paints that get immersed into such tanks are collected and have to be disposed off in an eco-sensitive manner. Companies who specialize in water treatment should be invited to provide solutions to ensure that the water in these tanks does not pose a hazard [11].
Actually no one can change the problem. Only awareness among the masses can reduce the pollution gradually.