KSPCB puzzled by preliminary data on lake pollution

All the publicity given tof Eco- Ganesha seems to have become futile this year again. The reports of pollution levels in water bodies project the reality. But the KSPCB, which released the report on Friday, seems skeptical of the findings and wants a re-study.

This year seems to have been a slightly eco-friendly Ganapati festival, claimed various press releases from BBMP and Karnataka State Pollution Control Board (KSPCB). But the statistics tells a different tale.

The drive of the KSPCB and the BBMP to influence people to celebrate an eco-friendly festival seems to have done little in curtailing the pollution levels in the lakes. KSPCB and BBMP had publicised the importance of eco-Ganesha in a large scale this year, through various media including Facebook, advertisements and campaigns.

This year around 1.2 lakh Gahesha idols were sold in Bangalore city – this is 40% of the total idols sold. In Mysore, the sale of eco-friendly idols was around 75%. Now the KSPCB has released the result of a survey done in four lakes, which indicates the level of pollution.

The list covers merely Ulsoor lake, Lalbagh lake, Yediyur lake and Yelemallappa lake. Major lakes like Sankey Tank, Byrasandra lake, Shivapura lake, Karihobanahalli lake, Mallathalli lake, Madavara lake and Hebbal lake are not included in this list. However, this is the first set of data released by the KSPCB. There are more such reports expected.

Explaining the sampling process, KSPCB scientific officer  B Nagappa says that samples are collected from one part of the lake and the report is attributed to the whole lake. Kalyanis get filled up in a short time and the water overflows into the lakes. So this makes the whole lake polluted.

‘Ward committees should superwise the sale’
Noted environmentalist AN Yellappa Reddy, who has worked extensively on lakes, points that the departments should have made the manufacturers of Plaster of Paris Ganesha responsible for collecting the sold ones back and dispose them scientifically. The KSPCB should have also publicised the exchange programme (return your old idols and take new ones) among people.

He suggests the following steps:

  • KSPCB and BBMP should empower the ward committees to oversee the activities of sale of idols and ensure more Eco-Ganeshas are sold.
  • They should be given the powers to take action against the sellers of chemical idols.
  • Stringent rules and campaigning needs to be done at public and private institutions- offices and educational centres
  • Strict action should be taken under the Water and Environmental Protection Act- which includes penalty and imprisonment.

Iron level much above the preferred level

The report shows that the level of iron has increased in the lakes. While the permissible limit is said to be 5000 micrograms per kilogram (mg/kg) in the lake sediment samples collected, it was reported be 6888.6 mg/kg before the festival in Lalbagh lake and after the festival the levels recorded were 7801 mg/kg. In case of Yelemallappa lake, the levels before and after the festival were recorded to be 22464 mg/kg and 22586 mg/kg. At Ulsoor Lake the levels before and after the immersions were 31000 mg/kg and 34000 mg/kg.

According to B Nagappa, iron in water bodies is not as dangerous as other chemicals like cadmium, chromium, lead and Plaster of Paris. Even clay has iron. Probably this explains the already high ratio of iron present in some of the lakes.

Water experts have a different view. According to water management consultant S S Ranganathan, such large quantity of iron has entered into the lakes primarily because of the paints used on the idols. The sewage entering the lake is another cause of pollution.

Kalyanis not of much use

Raghunathan also points that the kalyanis which are constructed, serve only half the purpose. Water does not stay stagnant, it flows. Kalyanis are basically a part of the lake, and there is a wall which separates them. So when water overflows, due to varied reasons (splashing, overflow, people moving and so on), chemicals also flow out. Thus the lakes get polluted. In Bangalore, no lakes are free from pollution. All lakes are contaminated. The KSPCB has failed in their duty of managing the lakes.

pH balance for water

The standard pH level for water is between 6.5 and 8.5. If the pH level is more the water is alkaline and if it less it is acidic in nature.

The KSPCB observes that the pH levels in some lakes have increased by 20% after the festival. This is because of the dissolution of clay, Plaster of Paris, adhesive materials and paints on the idol which were released into the waterbody during idol immersion.

However the survey throws in a surprise. In case of Lalbagh lake the level before the immersions was 6.6, which became 8.1 later. In case of Yelemallappa Lale the levels before and after the festival were reported to be 7.4 and 7.5, with no major change. But in the case of Ulsoor and Yediyur lakes which were alkaline in nature before immersion, with pH levels of 9.45  and 8.7 respectively, the alkalinity came down to 7.13 and 7.4.

Nagappa says that the pH levels keep increasing and decreasing because of the presence of Algae and because of photosynthesis. Ranganathan adds that pH levels do not affect humans to a large extent. However aquatic life gets affected by pH levels.

Click on the image to see details

Dissolved Oxygen level goes down

The levels of dissolved oxygen (DO) had reduced by 70%. This was because the pooja articles were not collected in advance at the Kalyanis, before the idols were immersed in water. The standard minimum level of DO in water should be four micrograms per litre, which is essential for the healthy survival of aquatic life. Reduced DO poses a serious risk for the survival of aquatic life.

Meanwhile the board also observes that the levels of bio-chemical oxygen demand in water has increased. The presence of impurities has a direct effect on the levels of DO and BoD in water. Ranganathan explains that if there are more impurities, Oxygen levels drop and then aquatic life dies. So it should be at a standard level (3 mg/ litre by KSPCB).

Pollution by metals within ‘permissible limits’

The level of metals in the lakes were within permissible limits. The list includes Copper, Lead, Mercury, Nickel, Chromium and Cadmium.

Lead: Surprisingly, no lead was reported in any of the three lakes this year and last year.  As per KSPCB norms, 0.1 mg/ litre can be present in the water body. Excessive lead can cause irreversible neurological damage, renal diseases, cardiovascular effects and reproductive problems.

Click on the image to see details

Mercury: Mercury, which is not permissible, was reported in Lalbagh lake measuring 0.003 mg/litre before immersion and 0.007 mg/ litre after immersion. Mercury leads to numbness of hands and feet, weakness the muscles, affects vision, causes speech and hearing impairment, leads to paralysis and even insanity. As per KSPCB norms Mercury should not be present in water at all.

Nickel: Nickel, which is not permissible as per KSPCB norms, was found in Yediyur lake. Before and after the festival the levels were recorded as 0.16 mg/litre and 0.42 mg/ litre respectively, while last year it was 0.24 mg/ litre and 0.39 mg/litre, before and after the festival respectively. Presence of Nickel leads to leads to skin allergies and dermatitis.

Chromium: Chromium which is not permissible as per KSPCB norms was reported in Yediyur lake. Before and after the festival it was recorded to be 0.001 mg/ litre and 0.002 mg/ litre respectively. this can lead to damage of kidney, liver and blood cells. This can also cause skin allergies and lesions.

Cadmium: Cadmium, which is not permissible as per KSPCB norms, was reported in Yediyur lake, measuring 0.02 mg/ litre and 0.04 mg/ litre, before and after the festival. Last year it was reported to be 0.02 before and after the festival in the same lake. Its presence in human bodies can lead to Osteoporosis, kidney failure and carcinogenic.

Ranganathan says that all chemicals like lead, iron, Nickel, Cadmium, Chromium and Mercury come into the lakes with sewage. Many paints contain them and should not be allowed in water because they are toxic. Many garage industries use lead, iron, Nickel, Cadmium and Chromium for car and bike painting. After their work is done, all the waste is thrown into the sewer lines untreated, which enters the water bodies. Mercury is found in residential and medical waste, which is not disposed properly and is entering the water. So people who fish in the lakes, are fishing the ones which contain these toxic chemicals. People who happen to eat such fish will ultimately consume these toxic chemicals, which could affect their health in the long run.

Report puzzles KSPCB

The report has many contradictions, like reduced alkalinity in some lakes, and no lead at all. Speaking to Citizen Matters, Chief Environmental Officer of KSPCB, Nandakumar says, “Even we are unable to understand the findings. This time we had outsourced the work of sampling to other agencies as many lakes were to be surveyed. This is however the first part of the report. Report on the rest of the lakes is awaited. In the meantime we are also planning to redo the survey of all the lakes by ourselves again, to arrive at a proper conclusion.”

He adds that the levels of Mercury, Nickel, Chromium and Cadmium are only traces. So it is not a matter of worry. “The report is only an indication. We need to still understand the cause and effect of the whole situation,” he explains.

However, there have been  Ganesha immersions last weekend too, which means that there is more to see in the next round of lake water sample survey.

Related Articles

Pollution in Bangalore less during monsoons, says KSPCB data
Pollution watchdog to support apartments for better STPs
Immersion sans pollution
Eco-Ganesha : Where to find him, and why?


  1. Vaidya R says:

    Appealing and educating people can get you only that far. Make a strict rule and clamp down on plaster of paris ganeshas and level of chemicals that an idol that can be immersed needs to be within. If they are harmful, why are they allowed to be sold? We are not doing a ‘favor’ to the lakes by using eco-friendly ganeshas. It is for our own sake!

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