Threats to safe drinking water

By: Andrew (Andy) Camphausen

What threat is posed by non-compliant plumbing practices, water-borne diseases and a disregard of environmental water practices?

When preparing and investigating this topic, I was amazed at the amount of micro biological diseases that are borne out of water. As I am not a microbiologist, the terms and scientific names are not mine, but I will try and explain this to the best of my ability.

This article aims to create awareness on non-compliant plumbing practices, water borne diseases, and the dangers of a total disregard of environmental water practices.

Water-borne infectious disease
From a public health point of view, the reliable supply of safe drinking water is a necessity for daily life. Unfortunately, the same water that sustains life can also be the bearer of dangerous contaminants in the form of bacteria, viruses and protozoans. These include bacteria such as Escherichia coli and Campylobacter, viruses like Norovirus and Hepatitis E, and protozoans like Giardia and Cryptosporidium. The risk of infection and disease and the public health burden is determined by the severity of illnesses that are caused by the pathogens, the extent of the exposure and the physical condition and susceptibility of the exposed population.

What is in water?
Natural bodies of water, such as rivers and ground waters, normally contain nutrients, but certain bacteria and viruses have evolved to take advantage of the environment. Most of these micro-organisms are not harmful to human beings.

However (and there normally is a challenge), it is common for sewage to be discharged into these waters without adequate treatment. Many micro-organisms in sewage pose a real threat to our health. Domestic and wild animal waste can also pose a danger. In Gauteng, the other danger would be from mine seepage into the ground water system which eventually ends up in our drinking water system which left untreated, will make our population very sick.

Humans may be infected by these pathogens by drinking contaminated water or by eating uncooked shellfish that have concentrated harmful organisms they have extracted from contaminated water. An example of this would be the periodic red tide that is experienced around our coastline. Also, leaking septic tanks and inadequate ‘long drop’ type toilet systems may be situated near to a drinking water source like a river or dam and the real danger of contamination could be realised.

A further cause of contamination of drinking water is through the improper storage of water in household storage tank and toilet cisterns. This is a common source of pathogens in developing countries like South Africa.

Which micro-organisms are important?
The most important micro-organisms that can make us humans sick due to contamination of water are:

  • Vibrio Cholera which can evolve into Cholera if not properly treated. E.coli lives in the digestive tracts of the human race and is mostly harmless but can cause diarrhoea and, in rare cases, can cause anaemia or kidney failure.
  • Hepatitis A is a self-limiting virus which, if not vaccinated, can cause liver failure.
  • Hepatitis E is much like A and also needs vaccination.
  • Norovirus is a very contagious virus that can infect anyone. You can get it from an infected person, contaminated water. The virus causes your stomach or intestines or both to get inflamed. This leads you to have stomach pain, nausea, and diarrhoea and to throw up. These symptoms can be serious for some people, especially young children and older adults.
  • Sapovirus is the Norovirus’ less known cousin and was only detected less than 10 years ago. It is especially vigorous in the aged society.
  • Rotavirus is the worst of the three and is contagious virus that can cause gastroenteritis (inflammation of the stomach and intestines). Symptoms include severe watery diarrhoea, often with vomiting, fever, and abdominal pain. Infants and young children are most likely to get rotavirus disease. They can become severely dehydrated and need to be hospitalised and can even die.

Legionella are among the exceptions to harmless growth organisms in distributed water. Legionella can grow to significant numbers in warm waters, geysers, spas, hot water lines and shower heads. Special precautions are required to prevent or control Legionella in health care facilities because aerosols or fine water droplets from showers and spas are a route of infection and those facilities contain high risk populations. Legionella grow well in water at temperatures in the range of about 25 to 50°C. Preventative and remedial controls are essential in hospitals and health care facilities. This is discussed at length in chapter 7 of SANS 10252:1, with regard to this often lethal disease.

Risks other than health issues

  • Hot water and scalding: Burns from hot tap/mixer water can result in severe injuries to young babies, children, elderly and disabled people. The SANS 10252:1:2012 (Part 7.1.2) is very clear on this issue. For example, water at 65°C can inflict a severe burn on a child in less than a second. While parents or nurses can help reduce the risk by checking bath water temperatures and supervising children, elderly or disabled people, the obvious answer to minimise the risk of scalding would be to lower the temperature of the hot water system. Caution is advised as hot water cannot be stored between 25 and 50°C without risking the potentially deadly Legionella disease. An alternative is to install thermostatically controlled mixing valves on applications like assisted showers, baby baths and baths.
  • Damage to buildings and land: Flowing water can exert significant force and under some circumstances this force can result in damage to buildings and to land. Plumbers should be aware of the potential damage to building structures that can be caused by water hammer. Proper pipe sizing will reduce this risk. Currently mechanical and wet services engineers are capable in fulfilling this role.