Yamuna dirtier in May, pollution load in major drains increases too

NEW DELHI: The pollution in the Yamuna spiked in May with a substantial rise in fecal levels, phosphates and ammonia. Delhi Pollution Control Committee 's monthly analysis shows that while the river was more polluted at its exit from the city at Asgarpur, it also entered the city at Palla with substantial pollution levels. The samples of the river were collected on May 1, a day before the city recorded heavy rains. The pollution load in major drains like Maharani Bagh, Shahdara and Najafgarh also increased in May.

According to DPCC, while fecal coliform has increased since last month, the river also recorded a spike in ammonia, with the ammoniacal nitrogen levels doubling to 5.7mg/litre from 2.3mg/l last month. The fecal coliform level reading was 23 lakh MPN/100ml in May, much higher than the 15 lakh MPN/100ml in April.

Experts, however, were concerned about the various test readings published by DPCC. Pankaj Kumar, environmentalist and founder of Earth Warrior, said, "If fecal coliform is high, then biochemical oxygen demand (BOD) must also increase. However, we see that BOD at Nizamuddin Bridge is 37mg/l and fecal level is 2.4 lakh MPN/100ml. At the next station at Okhla barrage, BOD drops to 23 and fecal coliform increases to 3.3 lakh. DPCC must recheck this rather big anomaly. At Palla, the dissolved oxygen (DO) level is 9.8mg/l and BOD is 4, which seems a bit unlikely because for DO as high as 9.8, BOD must be 1-2mg/l."

Another expert pointed out that high DO levels upstream of Wazirabad could depict algal growth. "If there is algal growth, then DO increases during the day and drops at night due to respiration. A DO of 9.8 mg/l appears out of proportion. Or it means there are nutrients like phosphate and nitrogen in the water. It is necessary, therefore, to carry out more testing," the expert said.

A Delhi govt official added, "Also, at Wazirabad BOD in Feb was 9mg/l, 7mg/l in March and 6mg/l in April and May; these are not even standards for bathing water. Is Delhi Jal Board also monitoring this?" The permissible BOD for the Yamuna is 3mg/l.