ocean blue project logo

Are Wildfires Contaminating Our Water Supply?


Are Wildfires Contaminating Our Water Supply?

By Kim DeGracia – Estimated reading time: 8 minutes

Brief Summary: Wildfires are affecting different parts of our world every year. What’s causing these wildfires? Why are they happening? What are firefighters doing to protect humans and animals from wildfires? Are our water supplies and aquatic animals affected by the wildfires? We’ll explore the answers to these questions in this blog post!

Wildfires are affecting different parts of our world every year. What’s causing these wildfires? Why are they happening? What are firefighters doing to protect humans and animals from wildfires? Are our water supplies and aquatic animals affected by the wildfires? We’ll explore the answers to these questions in this blog post!

If you’ve consumed news in the past months, you’re aware that wildfires are impacting many areas of our world. Some of these places include:

  • California and Oregon in the United States
  • British Columbia in Canada
  • Khanty-Mansi region of western Siberia
  • Kalimantan province in Indonesia
  • Pantanal wetlands in Brazil
  • New South Wales in Australia 

The United States National Interagency Fire Center reported that over 3.5 million acres have burned due to wildfires so far in 2020. Last year, 195,898 acres of land burned in the United States. The number of acres of wildland fires that have burned in 2020 has increased by 1709% since last year! Wildfire season is still not over, and each year wildfire season is starting earlier and ending later. 

Are wildfires normal? If so, why do they occur? Where do they occur? Can our water supplies be impacted from wildfires? Let’s learn more about the impact of wildfires on our waters!

The Why, Where and What of Wildfires

A fire needs 3 components in order to occur (also called the “fire triangle”): fuel, heat and oxygen. In wildfires, fuel includes biomass such as grass, leaves, twigs, branches, logs, and even homes and personal property. An ignition source such as a candle is needed to maintain a fire and causes it to spread. Lastly, oxygen is needed to sustain a fire. 
Fuel, heat and oxygen are present when wildfires occur, but why do wildfires start in the first place? Where are wildfires most prevalent? What are firefighters doing about these fires?  We’ll answer these questions in the following sections.

Why Do Wildfires Occur?

Wildfires are uncontrolled fires that burn in wildland vegetation including forests, savannas and grasslands. They have historically been a natural part of ecosystems. Nature uses wildfires to clear away dead plant debris; this allows for nutrients to return to the soil and enables vibrant and healthy new plants to grow. Unfortunately, this cycle cannot occur if wildfires burn for too long or the ground stays dry and can’t provide water to future vegetation. 
A new cycle is beginning where climate change leads to longer droughts, more wildfires for longer periods of time, and more carbon in the air. While newly grown trees could have removed this excess carbon in the air, the carbon remains and perpetuates climate change.
In addition to climate change, the United States National Park Service reports that about 85% of wildland fires are caused by humans. Some human activities that cause fires include burning debris, cigarettes, intentional arson, campfires or barbeque grills left unattended, or equipment malfunctions such as power lines or flat tires. Lightning can also contribute to fires. 
While some may think that suppressing fires is beneficial, fire suppression in the past has made today’s wildfires worse. When humans extinguished fires in the past, plants and trees that rely on fires for rejuvenation did not burn. Hundreds of years later, we’re left with an accumulation of plants that can be used as an ignition source for today’s wildfires. This is why the United States Fire Service is trying to fix this problem through controlled burns.

Where Do Wildfires Occur?

In states such as California, many homes, commercial buildings and small towns have been built in or near wildland vegetation. This area is called the wildland-urban interface – WUI. While the WUI has seen an increase of over 40% of homes since the 1990s, it’s the fastest growing land use type in the contiguous United States. 

Since there have been an increase in the number of homes in the WUI, there is an increase in the number of people living in these areas where houses and wildland vegetation meet or intermingle. We know that humans are the number one cause of fires, and with a densely populated area this risk increases in the WUI.

What Are Firefighters Doing to Fight Wildfires?

The combination of climate change, human behavior with ignition sources, trees and wildland debris and oxygen all contribute to a wildfire occurring. If firefighters want to put out the fire, one of the 3 components of the fire triangle must be removed. For example, using water to extinguish the fire can remove oxygen from the fuel. In order to prevent fires, firefighters can remove dead tree debris and other biomass that may be used as fuel to intensify a fire. 

One common method to help fight wildfires is to use a tanker aircraft to drop streams of red flame retardant on vegetation called Phos-Chek®. Phos-Chek® was first commercialized in 1963 by Monsanto and subsequently approved by the United States Forest Service. Its active ingredient is ammonium phosphate, and it’s dropped on vegetation surrounding a fire and not on the actual fire. The firefighters hope that the vegetation that has flame retardant will not catch on fire so the fire will not spread further. We will speak further about flame retardants in the next section of this article.

The Connection Between Water and Wildfires

Forests make up about 31% of our earth’s landmass. They provide high quality water for agricultural, domestic, ecological and industrial purposes. Forests’ water supplies are healthy because the water comes from areas with high annual precipitation, high runoff and low contaminant concentrations. Forests provide almost ⅔ of towns in the United States and ⅓ of large cities such as Rio de Janeiro, Tokyo and Melbourne with drinking water

Forests provide a large amount of drinking water to our world’s populations, but when wildfires occur in these forests the water is impacted. We’ll explore if chemicals from wildfires are leaching into our drinking water and how land-based animals are impacted by these fires.

Are There Chemicals Contaminating My Drinking Water?

When a wildfire occurs, the soil heats up to 1,000°F (550°C) and releases a high amount of organic material contaminants from the soil. Water from rain will carry the contaminants to watersheds, and the amount of contaminants increases up to 700%. Drinking water can be contaminated with chemicals and microorganisms. Hundreds of thousands of dollars are spent trying to remove these contaminants so the water is safe for consumers. 

Professor Ben Livneh of the Department of Civil, Environmental and Architectural Engineering at the University of Colorado Boulder studies the impacts of land and climate change on water resources. Livneh and his group have created a wildfire and rain simulator that measures the amount of organic contaminants present in the waters. They are hopeful that their findings will inform the public about their water supplies and also help water utilities plan ahead of wildfires to treat the water.

Another scientist who is making an impact with their research on wildfires and water quality is Dr. Newsha Ajami, a hydrologist and director of Urban Water Policy with Stanford University’s Water in the West initiative. Since more homes and infrastructure are being built in the WUI, they are at a high risk for catching on fire. 

Many of the materials commonly found in homes, buildings and cities in the WUI include electronics, appliances, batteries, paint and flame retardants. The combustible products of these materials after a fire include possible carcinogens such as polyaromatic hydrocarbons, heavy metals and flame retardants. Ajami mentions that fire debris from these materials can be transported to bodies of water through rain. The contaminated water then has to be purified to be safe for drinking. The water can also affect crops, posing a safety risk for consumers and financial risk for farmers.

Dr. Mussie Beyene, scientist and postdoctoral researcher with the United States Environmental Protection Agency (US EPA), states that water supply managers are concerned with changes in the magnitude, frequency and timing of water discharge and sediment. Water supply managers need to ensure that water treatment plants and water storage systems can handle this strong water discharge. Drinking water utilities also need to ensure polluted water is treated, floods are managed and residents are supplied with clean water during or after a wildfire.

How Are Aquatic Animals Impacted By Wildfires?

We know that humans are impacted by wildfires, but aquatic animals are also affected by wildfires. When a wildfire occurs, the heat from the fire can increase the water temperature. The increase in water temperature is detrimental to some fish species such as salmon that can’t survive in warm waters. Wildfires also impact fish by increasing the pH of water due to alkaline wood ash and removing oxygen from water due to algal blooms dying and decomposing. 

Wildfires cause plants to create a gas that condenses to a waxy coating on the soil. This waxy coating will repel water, so the soil is not able to soak any water in. Instead, the runoff water collects into streams that begin to flow faster and stronger. The increased water runoff causes erosion that block water or change the courses of rivers. 

Lastly, while wildfires may help a variety of plants to rejuvenate, the toxic gases and fire debris are hazardous to aquatic life. For example, the black ash from fires can clog fish gills and coat the bodies of fish. Fire retardants such as polybrominated diphenyl ethers (PBDEs) are carcinogenic to humans and are found inside organs of fish. Some researchers have found that flame retardants cause structural deformities in fish, impair their cerebrospinal fluid flow and cardiovascular function, and may even cause death.

What Can We Do to Help?

We know that wildfires are contaminating our water supply and affecting humans and aquatic animals, but what can we do to help? Ocean Blue Project collaborates with local communities and governments to ensure wildlife and humans can coexist. Local governments play a foundational role in ensuring the water you consume is safe.

Sign up for our OBP email newsletter and follow us on our social media platforms to stay informed with what we are doing in our local communities and governments.

While wildfire debris can contaminate water supplies, plastics can also leach chemicals into runoff. Contact OBP for support in organizing your own ocean and river cleanups to ensure chemicals and microplastics are not adding to the contamination of runoff. Lastly, you can donate to OBP and join our commitment to removing 1 pound of plastic per $1 donated.

While wildfires may seem like a big problem that our world is facing, you can make a difference through partnering with OBP!

Author Bio: Kim DeGracia is a scientific writer and clean-water advocate based in the Washington D.C.-Maryland area. She is a postdoctoral researcher at a firefighter research institute studying how fires impact our environment.