Heavy toxic metals killing sparrow

Gurvinder Singh

Tribune News Service

Ludhiana, June 15

No longer restricted to industry, pollution is affecting the crops too, as is evident from heavy metals found in the house sparrow, according to a study conducted by Punjab Agricultural University here.

  While the levels of lead and boron in sparrows were found above the ‘toxic’ range, those of metals like arsenic, nickel, chromium, cadmium and zinc were higher than normal.

“These conclusions were drawn after analysing the constituents of the excreta of birds, which is an effective way to study heavy metal traces without causing any harm to the birds,” Dr Tejdeep Kaur Kler, senior ornithologist with the university, told The Tribune.

“The presence of heavy metals in the excreta of the house sparrow indicates contamination of the bird’s agricultural habitat and subsequently the contamination of the bird’s food chain, further raising fears that not just birds but heavy metals might have entered the human food chain too,” explained Dr Kler.

Heavy metals have deleterious effects on the population of birds because these affect the functioning of organs and, hence, the longevity of birds. The metals trigger reproductive dysfunction, hatching failure and thinning of egg shell. The chronic degenerative changes is one of the primary reasons for the decline in the population of birds.

In Punjab, Dr Kler said, untreated effluents from the industry comprising heavy metals were being discharged into the river waters used for irrigation purposes. “That is how these are reaching the fields and entering the food chain. The cattle egret in villages alongside the Buddha Nullah is the worst-hit.” 

No traces of pesticides, often blamed for polluting agricultural produce, were detected in the bird excreta, “as these break into harmless compounds over a period of time,” she said.

The university’s Zoology Department had in an earlier study found traces of heavy metals in the common myna, blue rock pigeon, ring dove, cattle egret and the house crow. The excreta for the study was collected from farms across Ludhiana district.