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After a disastrous flood, more hazards: what is in floodwater?

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Cristina Novo
Technical Editor at Smart Water Magazine.

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  • After disastrous flood, more hazards: what is in floodwater?

Besides the obvious damage caused by water, floods can also prove dangerous even after the water starts to retreat. Floodwater can be polluted with sewage and chemicals. Moreover, standing water can hide other dangers: sharp objects, animal carcasses, open manholes and electrical hazards.

A BBC article points out some of the infectious diseases and other hazards people are exposed to through floodwater. Water can bring everything in the drains and sewers back into the street and into homes, so people in flooded areas are warned to keep as far away from the water as they can. ‘Don’t splash about in flood water’ cautions Sanjay Jahal, of the National Flood Forum, a UK non-profit.

Sewage contaminated water can be a source of many diseases caused by bacteria and viruses. These hazards do not go away after the water recedes. Clean up efforts will need to get rid of contaminated items and disinfection. Things like sandbags that have come in contact with chemicals or sewage may need disposal as hazardous waste, according to UK government advice.

Also, household, medical and industrial chemicals can be released into the environment during floods. The US Centres for Disease Control and Prevention (CDC) have issued some guidelines for the public on floodwater safety. Chemicals may have moved from where they are usually stored. It is dangerous to move propane tanks, and extreme caution should be used when handling car batteries, which could still have an electric charge, and may spill acid.

Some things we cannot see when covered with flood water can also pose a hazard. For example, glass or metal fragments can cause injuries. Infection of open, new or existing wounds is also possible when in contact with dirty flood water, so it’s important to protect them, keep them clean, and seek medical attention if concerned. Animal carcasses carried by flood water can also transmit certain pathogens. It’s important to check with any existing regulations regarding disposal of dead animals. Electrical hazards deserve special mention, either inside or outside the home: it’s important to never touch fallen power lines and to shut off domestic power to avoid electrocution.

Furthermore, in the aftermath of disasters, surviving animals like rodents and snakes may relocate looking for food and shelter, ending up in homes. Insects may proliferate in water logged areas so it’s important to take it into account in terms of avoiding mosquito-borne diseases.

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