Think before you swim: What you need to know about coliform in seawater

Rose Carmelle Lacuata, ABS-CBN News

Posted at Apr 17 2018 11:51 PM

MANILA - If you think the only danger in swimming in the open seas is drowning, then you have to think again.

The government has started cleaning up popular beaches and tourist destinations as Filipinos gear up for summer. 

The most recent casualty is top tourist destination Boracay, which President Rodrigo Duterte dubbed a "cesspool."

In 2008, the government also prohibited swimming and diving in Manila Bay due to pollution.

One of the most common problems in beaches? Water that may be unsafe for swimming.

The Environmental Management Bureau (EMB) of the Department of Environment and Natural Resources (DENR) classifies different bodies of water according to use. 

Recreational Water Class 1 covers those intended for primacy contact recreation, which includes bathing and swimming, while bodies of water intended for fishing and irrigation, among others, falls under a different category.

Bodies of water intended for recreation are deemed safe if they fall within 100 MPN (most probable number) per 100 mililiters of fecal coliform.

Bodies of water used for fishing or irrigation, on the other hand, are safe if they have less than 200 MPN/100 ml of fecal coliform.

In a report released by EMB in 2016, only two recreational bodies of water, Puerto Princesa Bay and Boracay, has "good" water quality in terms of fecal coliform.

Four bodies of water failed to meet the 200 MPN/100 ml fecal coliform. These are Manila Bay, Nasugbu Bay, Coron Bay and Iloilo City coastline.


According to the World Health Organization, recreational waters, or the ones used for swimming and bathing, generally contain a mixture of pathogenic and non-pathogenic microorganism.

These microorganisms come from different sources, such as the population using the water, sewage effluents, livestock, farming activities, wildlife and domestic animals, among others.

The most common form of microorganisms found in recreational water is coliform. The presence of coliform in water means its has come in contact with plant or animal life.

Although some coliforms are harmless, there are some that can cause illnesses.

Fecal coliforms, are coliforms that come from human or animal feces. 

Once ingested, these microorganisms can cause gastrointestinal infections. They can also cause infections on the ears, eyes, nasal cavity or the skin.

One of the most common symptoms of gastrointestinal infections is diarrhea, which is the second leading cause of death in children under five years old, according to data from WHO.

Diarrhea is defined as the passage of three or more loose or liquid stools per day (or more frequent passage than is normal for the individual). 

"Diarrhea is usually a symptom of an infection in the intestinal tract, which can be caused by a variety of bacterial, viral and parasitic organisms. Infection is spread through contaminated food or drinking-water, or from person-to-person as a result of poor hygiene," WHO said in its website.

There are different types of diarrhea, which includes acute watery diarrhea (lasts for several hours or days), acute bloody diarrhea (also called dysentery) and persistent diarrhea (which lasts for 14 days or longer).

If left untreated, diarrhea can cause severe dehydration and fluid loss, which causes death.


It is important for swimmers to be responsible and avoid spreading diseases as much as possible.

It is better not to swim if you are suffering from any illness or any contagious disease.

Practice proper hygiene. Take a quick shower before and after swimming to prevent the spread of microorganisms.

To prevent diarrhea or other gastrointestinal illness, it is important not to swallow the water from the pool or the beach.

"Kaunting-kaunti na malulon mo lang 'yan, 'pag natiyempuhan na mababa ang immune system natin, lalo na 'yung mga bata, matanda, may sakit, at nakainom nito, maaring magkaroon ng diarrhea o sakit sa tiyan," Dr. Lia Nebrida-Idea told DZMM in a 2017 interview.

To prevent swimmer's itch, it is also important to rinse with soap and water immediately after getting out of the water.

"Pag-ahon natin sa swimming pool o sa beach, parang mga butlig butlig na pimples na makati, mapula. It's like an allergic reaction doon sa mga parasites na nakikita sa tubig. Ang nangyayari, dumidikit siya sa balat natin. Ang only way para hindi magkaroon ng pangangati is to rinse off with soap and water," Idea added.

To keep the cleanliness of beaches and pools, it is important to remind everyone, especially children, not to urinate in the pool or beach.

It is also not advisable to spit or blow your nose in the water so as not to endanger other swimmers.