RESEARCH ROUNDUP – POWERED POLLUTION

Delhi’s polluted air has been in the headlines for months now, often lead ing to comparisons with Beijing, one of the most polluted areas in the world. Now, a team of researchers from the University of Michigan has found that illegal battery recycling business in the capital city is adding to its polluted air increasing the airborne lead levels two to eight times higher in those neighbourhoods, well above recommended health guidelines.While pinpointing the location of some recycling facilities sources is challenging as they can be moved, the findings show higher lead levels in the western and northwestern portion of the city. If you have one of these illegal battery recycling operations in your neighbourhood, you are likely breathing a lot more lead in than someone a few miles away,“ says senior author Andrew Ault, assistant professor of environmental health sciences in the U-M School of Public Health.

“It means getting exposed to in a few days what might take a roughly year or more in the US,“ adds first author Hongru Shen, a doctoral student in environmental health sciences at the school.

The original study, led by Naresh Kumar, at University of Miami, was focused on air quality in Delhi and Kanpur and trying to understand how the concentrations of air pollution changes across those major metropolitan areas, especially after CNG regulations in Delhi. Kanpur was chosen as a reference site, as it did not enforce any CNG regulations. “We weren’t even looking for lead particles, they jumped out of our analysis and caught our eyes. But we needed to figure it out since it is so harmful to both environment and people’s health,“ Shen says. The other authors of the study were Thomas Peters, University of Iowa; Naresh Kumar, University of Miami, Gary Casuccio, Traci Lersch and Roger West, RJ Lee Group, Inc Pennsylvania; and Amit Kumar, Society for Environmental Health, Delhi, India.

Using sophisticated microscopic equipment and a lot of detective work, the re searchers were able to pinpoint the likely source of lead particles in the air at sites in Delhi because of much higher concentrations that didn’t match with the usual sources of lead.

More typical lead particles in Delhi air are distinguishable as having originated from coal-fired power plants, incinerators, leaded fuel, re-suspended road dust and aviation fuel, the researchers said. The backyard operators who illegally recycle 89% of lead batteries in Delhi use wood-like fuels to heat the lead over a flame. Because they are illegal, these recycling activities are operated intermittently and can move from neighbourhood to neighbourhood, creating lead hot spots as also making them more dangerous. The collaborative team of researchers took samples across Delhi from August to December of 2008 and then analysed them using computer controlled scanning electron microscopy coupled with an energy dispersive X-ray analyser that provides elemental information.

The researchers chose 50 sites for particle collection.Of these, 25 were analysed and found to have particle concentrations ranging from 0.0 to 6.2 micrograms per cubic meter (the U.S. standard is 0.15 micrograms per cubic meter). Four had levels high enough to be considered “lead events,“ with mass concentrations greater than 1.4 micrograms per cubic meter. Most research checking lead levels in the air weighs the amount of an element, whereas this team looked at thousands of individual particles to gain a better understanding of how they were formed. Elaborates Ault, “We used an automated electron microscope that lets us essentially take pictures of individual particles and see what elements are in them. Based on the size, shape, and composition we were able to see some other emitted elements, which pointed to how the particles were made.“

Other clues about where the particles were coming from had to do with the weather and wind direction.

Normally, high lead levels are found in winter, not the monsoon season. So when the researchers found elevated levels during all seasons sampled, and at higher than normal levels during specific seasons, it was further evidence that the extreme concentrations were from local sources. Wind patterns ruled out the source as power plants or other industries.

Though many researchers say there is no safe level of lead, excessive lead in the air, water and other sources has been found to cause health issues from high blood pressure to gastrointestinal issues, impairment of the nervous system in people of all ages, and neurological problems in children.