After Hurricanes Harvey and Irma. Natural Disasters and The Pollution Risk — A Pure Earth Q&A

“Dhaka” Photo by Sumaiya Ahmed, Creative Commons

The recent Hurricanes (Harvey in Texas, Irma in Florida and the Caribbean) with their extensive floods have raised questions of pollution and other chemical contamination. This is an important public health issue that many times gets lost in the early days of a disaster when rescue and recovery are underway. Afterwards residents realize that the water surrounding them is far from clean. The New York Times reported that tests of floodwaters in some Houston neighborhoods revealed the presence of toxins at levels above what was considered safe.

At around the same time, thousands of miles away, monsoon rains wrecked havoc in India, Nepal, and Bangladesh. Similar pictures of people wading through floods were seen. The risks for anyone caught in such a situation is dire, but the threats are more likely to persist and be more severe in low- and middle-income countries (LMICs), with far less infrastructure and resources to deal with residential and industrial waste, even before the advent of a natural disaster.

Pollution and natural disasters know no boundaries. So what are the actual risks and what can be done? We talked to Pure Earth’s director of research Dr. Jack Caravanos, who is also a professor at NYU’s College of Global Health.

What are the hazards? Isn’t it just massive amounts of rain or storm surge?

You are right, there’s a lot of rain. It’s relatively pure, but water and flooding causes many chemicals to be re-mobilized. For example, the sewers and sewage treatment plants get flooded and spill over into neighborhoods, so we have human excrement dissolved in the water as well as detergents and cleaning chemicals. Even though this is very much diluted, pathogenic bacteria and viruses are now distributed everywhere. The most notable waterborne threat being cholera.

But people don’t drink this water, so where’s the risk?

No one intentionally drinks this water, but inadvertent hand-to-mouth activity occurs all the time and puts rescue workers and residents at risk. Then when the floodwaters subside, you have microbially contaminated furniture, clothing, automobiles and much more. Even canned food is at risk, since dried floodwaters leave a microbial residue. People don’t often disinfect cans, plates or flatware before using them.

Is this why cholera seems to always be of concern after disasters in LMICs?

Yes, cholera is a bacterial pathogen excreted in human feces. You don’t need many people with this disease to contaminate floodwaters. And since it is transmitted via the fecal-oral route, just ingesting a tiny amount of contaminated water can infect a person. In LMICs, cholera still infects many people and mostly after a flood disaster.

And what about chemicals, do they also get mobilized during disasters?

Absolutely and the source can be residential or industrial. Consider that people apply pesticides or fertilizers on their lawns or gardens. After a flooding event, these agents move into the aqueous phase (the water) and move about like bacteria and viruses. And your automobile is also a source of many contaminants. Gasoline will leak out, so will transmission fluid, lubricating oils and even air conditioning coolants. Do the math, and you’ll quickly appreciate, that’s a lot of contamination. Luckily it gets quickly diluted, but even small amounts can present some risk.

You mentioned industrial sources, I thought all toxic chemicals were highly regulated and in secure containers. Do they leak out?

You are correct that in the USA, very hazardous chemicals including toxic and flammable chemicals are heavily regulated and unlikely to leak out during a flood. But during a hurricane or tornado, such precautions may be breached. And if there’s an electrical failure, it’s possible that a preventative cooling system may fail and the chemical container ruptured. Something akin to this already happened at a chemical plant in Texas during Hurricane Harvey. But the most infamous example was the tsunami-induced failures at the Fukushima Nuclear Power Plant in Japan.

So chemicals can leak into the floodwaters from gasoline stations, dry cleaners, laundromats, hardware stores, and so on. Anything else?

What concerns me the most are active environmental remediation sites. Whether it’s an asbestos removal going on in a school, or an underground petroleum storage tank, contaminated soil being removed, or a Superfund site being worked on; all these sites are very vulnerable during a disaster and present serious high level chemical risks should flooding occur. Fortunately, a hurricane’s relatively slow movement gives authorities ample time to institute some preventative measures. But tornados, fires and other natural disasters, do not give emergency workers ample time to prepare for the worse.

You do a lot of work in LMICs. How is the problem similar or different in those countries?

Everything in LMICs is exacerbated, and sometimes by orders of magnitude. Two common features of high-income countries are “response” and “resiliency.” How quickly can resources be mobilized to minimize harm and how flexible or recoverable is the society and economy. Regrettably, both of these are often absent in LMICs. Environmental regulations are often lacking so containers are not properly sealed and stored; fail-safe systems are either absent or inoperative; and of course, contamination is more rampant.

I remember investigating one battery recycler in Bihar, India, who collected used lead-acid car batteries to brake them apart and re-processes the lead for resale. Hundreds of batteries were stored outside and workers often dismantled the batteries in the open. It was a cloudy day and all of a sudden the sky opened up and it rained.

I’m used to heavy thundershowers and this was memorable. But what caught my eye was the grayish runoff flowing everywhere. Essentially, the rain had washed all the surface lead oxide into rivulets and into the local streets and streams. Rarely have I seen sewers in these villages so the neighborhood contamination was pervasive. So if this was one factory during a summer rainstorm, can you imagine the environmental contamination following a cyclone? In fact I hear Bihar was hit by the recent monsoon rains that happened at about the same time as Hurricane Harvey in the US, and I fear toxins have been spread throughout the community.

So what’s the answer for these communities? What’s the intervention?

The solution lies in being prepared. These storms, tornados, tsunamis, fires will come. We don’t know the precise moment but it is possible to be prepared for the arrival and be ready to respond. Emergency preparedness following hazardous chemical releases or mobilization is commonplace in high-income countries; though not always perfectly applied.

In LMICs emergency preparedness is usually absent or just a “paper” program. This has to change. Pure Earth is helping LIMCs build capacity for pollution control, and raising awareness about low-cost solutions to pollution, which exist. We are also supporting cleanup of the world’s worst polluted places, which is key. If a polluted community is decontaminated, that reduces the overall exposure and spread of contaminates during a disaster.

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