How Does Rainwater Get Dirty And Impure In Monsoon?

Sources of Contamination

Dust in the air, dissolved gases, and acids are the primary factors that affect the purity and quality of rainwater.

• Dust particles, smoke, germs, parasites, and bacteria naturally get added to rainwater as it falls from the skies.

• Dissolved gases (for example, carbon dioxide) already present in the air get mixed with rainwater to make it impure.

• Acids (like sulphuric acid and nitric oxide) emitted due to air pollution mix with rainwater and affect its purity.

If you are using rainwater collected in containers (as part of your rainwater harvesting methods), you must be wary of these facts:

• Dry leaves and soil particles already present in the roof may contaminate the rainwater you have collected in your container.

• If your roof has a covering made of dangerous metals like asbestos, residues of such metals and paints may affect rainwater purity.

• The water collected on your roofs may actually be dirty rainwater because it may contain small elements of bird, animal, or insect droppings.

Some common germs that contaminate rainwater are Rotavirus, E. coli, Enterovirus, Norovirus, Salmonella, Cryptosporidium, and Hepatitis A virus. The common chemical residues found in dirty water are copper, lead, nitrate, arsenic, and radon.

Associated Health-Risks

It can not be said with full conviction that rainwater is 100% safe. Studies have proved the presence of bacteria, viruses, harmful chemicals, and other residues in rainwater. Hence, you should never use rainwater for drinking, cooking, or washing. It is better not to use untreated rainwater, even for watering edible plants.

Dirty water that is not treated or purified can lead to several health risks, such as:

• Cholera –

Extreme diarrhoea, dehydration, nausea, digestive issues, etc.

• Diarrhoea/Dysentery –

Severe loose motions, vomiting, nausea, etc.

• Typhoid –

Fever, body pain, constipation, pain in the muscles and joints, etc.

• Hepatitis A –

Vomiting, decreased appetite, jaundice, skin rashes, high fever, etc.

• Giardia –

Gastrointestinal issues, irritation & pain in the abdomen, bloating, etc.

Purification Methods

When these health risks are not diagnosed and treated properly, they can lead to severe complications and even death in some cases. Hence, you must never consume dirty rainwater, even if it has been sourced from fresh rains. Remember to purify it before you use if your regular needs. The purification methods that can be used includes:

• Boiling –

Always boil dirty rainwater for at least 10-15 minutes to get rid of the germs and bacteria. However, boiling alone is not enough if the water in your area has a lot of chemical residues.

• First Flush Diverter –

This removes some contaminants from the water collected on your roofs before it gets stored in the containers for further use.

• Filtration and Chemical Disinfectants –

Using appropriate water filtration systems and chlorine/iodine to treat dirty rainwater can prepare it for use.

• Screens –

Use screens to cover the tank’s inlet pipes to prevent insect, bird, and animal droppings from polluting water.

• Gutter Screens –

Install gutter screens to prevent debris from entering rainwater sources.

• Instal Covers –

Cover the tanks tightly at all times.

• UV Rays –

Use ultraviolet rays for treating rainwater.

FAQs

1. What are the best purification methods for dirty rainwater?

According to experts, some of the best methods for treating/purifying dirty rainwater are reverse osmosis, filtration, and mechanical filtration.

2. Why waterborne diseases due to dirty rainwater are more common during the monsoon?

During the monsoon, factors such as contaminated drinking water, open drainage systems, untreated sewage water, and water stagnation are quite prominent. Hence, waterborne diseases like cholera, typhoid, hepatitis A, and diarrhoea are common during this season.