Road salts are crucial for decreasing automobile accidents, but they can have unintended consequences on the environment, as freshwater salinity increases and impacts drinking water quality. 

Analies Dyjak, M.A. & Christina Liu, B.S., M.B.A.   

Globally, we have lost one-third of the world’s forests, or 2 billion hectares (an area twice the size of the United States). More often than not, humans are responsible for deforestation. The land that surrounds a body of water plays a critical role in water quality and availability. Forested land not only acts as a “natural filter” for incoming water, but also reduces the risk of flooding.

What Is Deforestation?

Forested areas are cleared to make way for agriculture, commercial buildings, homes, and other large scale construction projects. Deforestation results in significant changes to the surrounding and global ecosystems, and habitat loss can lead to species extinction. The most extreme examples of this include the Amazon Rainforest, which has shrunk 18% in the last 40 years. Illegal mining, illegal logging, agricultural expansion, lack of government control, and climate change have all contributed to deforestation in the Amazon.

Deforestation has lesser-known secondary consequences that are becoming a focal point for scientists. Trees absorb carbon dioxide and release oxygen back into the environment. Without trees, the carbon accumulates in the atmosphere which contributes to rising global temperatures. 

How Does Deforestation Impact Drinking Water Supplies?

Reduction in Rainfall and Global Implications:
Forests help control the water cycle by regulating rainfall and evaporation. The layers of the forest canopy, branches, and roots store and release water vapor, which helps to control rainfall. Forests also help reduce the impacts from flooding by blocking and slowing down the flow of runoff from storms. Deforestation, however, weakens this process, leading to irregular rainfall, including drought and flooding.

Also, while deforestation may occur locally, its effects are global. For example, in a 2005 study, deforestation of Central Africa caused a decrease in precipitation of about 5%–15% in the Great Lakes region, mostly centered in Illinois, with a peak decrease of about 35% in February. In addition, a 25% decrease in rainfall in Texas was attributed to Amazon deforestation. While the three major forest basins do not respond the same, deforestation in other areas have also been observed to cause changes in rainfall and the water cycle elsewhere in the world. The decrease in rainfall combined with the increase in water usage across the United States are contributing to severe drought and aridification throughout many states.

Increased Erosion and Runoff:
Forested land does a lot of the “heavy lifting” in terms of filtration. Soil absorbs pollutants and helps to slow the rate of flowing water. The tree roots also anchor soil against erosion, which reduces runoff, and lowers downstream water treatment costs. When forests are disturbed and degraded, (from deforestation or wildfires or a combination of the two), sediment flows into streams and pollutes water.

Reduced Water Quality/Access to Drinkable Water:
Scientists conducted a study in Malawi on deforestation and water quality. They found that when deforestation increased 1%, it was equivalent to a nearly 1% decrease in access to clean water, which was equivalent to a decrease in rainfall of nearly 10%. They also observed that access to source water did not mean people had more drinkable water. Deforestation increases soil erosion, resulting in higher soil, sediment, and turbidity levels in the water, increasing the need for drinking water treatment.

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Emily Driehaus  |  Science Communication Intern
**Updated 6/30/2022 to include latest updates

The ongoing drought in the western United States has severely depleted water supplies and left many states with water shortages. It's been going on for so long that it's now being called "aridification" in certain areas. Water restrictions have been implemented in parts of California and other western states. The lack of water can have an impact on both drinking water quality and water infrastructure. 

Droughts and Water Supplies

The most apparent impact of a drought is the loss of water resources due to the lack of precipitation. An increase in temperature can also speed up the rate of evaporation of water from water supplies. This combination of factors can lead to drought conditions like what is currently being seen in the western U.S. Both natural bodies of water and human-made reservoirs are being depleted at alarming rates, leading to water shortages and restrictions. 

How Can Droughts Impact Water Quality?

A U.S. Geological Survey study found that droughts may lead to elevated levels of naturally occurring arsenic in private wells and groundwater, and that the longer a drought lasts, the higher the probability of arsenic concentrations that exceed EPA’s standard for drinking water. Arsenic is naturally occuring in bedrock and sediments around the world and is commonly reported in private wells. Continued exposure to arsenic from drinking water is associated with an increased risk of several types of cancers and other adverse health effects.

A lack of rainfall can lead to reduced flow of rivers and streams, causing stagnation. Rainfall and other precipitation helps to keep rivers and streams flowing, but this stagnation from a reduced flow can lead to a buildup of pollutants. Microorganisms and viruses can contaminate stagnant water and can be transmitted through both drinking water and water used for watering crops. People who use private wells for drinking water are also more susceptible to these contaminants, as there is little flow during a drought. Additional water quality impacts during a drought include; turbidity, taste and odor, pathogen concerns, and challenges in managing disinfection byproducts (DBPs).

Impacts on Water Infrastructure:

The low water supply caused by droughts can have an impact on water systems, especially smaller systems. Poor water quality can affect a treatment facility’s ability to meet acceptable drinking water standards. This loss in water pressure can lead to boil-water advisories, which can add to the heat that often accompanies drought. Older pipes can also exacerbate water loss during a drought due to leaks.  

Future Considerations

With climate change increasing the frequency and severity of droughts, the EPA is looking to help communities with drought resiliency. These efforts include installing water-efficient plumbing, such as low-flow toilets and showerheads that conserve water. Encouraging water reuse is also part of these efforts. For example, using water from a shower to water plants could be part of these efforts. In addition, many states have begun programs to encourage or require drought-tolerant plants and landscaping be installed in place of lawns. In fact, for each square foot of grass removed, homeowners save an average of 44 gallons of water a year. As climate change exacerbates the impacts of droughts, these water conservation efforts will become increasingly important.

How Do I Prepare for Water Shortages in a Drought?

According to the USGS, preparation before a drought should focus on water conservation. Replacing leaky plumbing and installing low-flow fixtures can conserve water in the long run, especially during a drought. During a drought, the Red Cross recommends not pouring water down the drain when it could be used for another purpose, such as watering plants. Conserving as much water as possible will allow for more water from faucets to be used for drinking during a drought.

Analies Dyjak, M.A. | Head of Policy   

Recent testing requirements in the State of Massachusetts have forced local governments to take a closer look at the safety of their drinking water. These new requirements have revealed that Easton, Massachusetts, has elevated levels of PFAS in their tap water. This article will address what PFAS compounds are, the levels in Easton drinking water, and water filtration brands that actually remove them. 

PFAS in Easton, Massachusetts

The City of Easton, Massachusetts recently reported that PFAS are present in the city’s drinking water supply. State-level regulations of PFAS chemicals are relatively new, particularly in Massachusetts. Municipal water supplies were not required to even test for PFAS compounds until January 2021, when the state implemented these requirements. Up until that point, people in Easton and many other municipalities in Massachusetts did not know they were being exposed to this potentially cancer-causing chemical. 

In October, 2020, the Massachusetts Department of Environmental Protection set an enforceable standard of 20 parts per trillion for the sum of six PFAS compounds in drinking water. The six compounds, called PFAS6, are: PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA. This regulation means that if a water sample exceeds 20 parts per trillion for all six compounds, that the municipal provider is in violation of the state law. The table below shows elevated levels of PFAS in Easton source water. A more detailed and thorough analysis of these results can be found on the Easton, MA, website dedicated to PFAS testing.   

What Are Per and Polyfluoroalkyl Substances?

Per and Polyfluoroalkyl Substances (PFAS) are a category of harmful compounds that can be found in drinking water sources across the country. PFAS can take hundreds of years to degrade in the environment which is why you may see them referred to as ‘forever chemicals.’ PFAS are not currently regulated at the federal level, but some states have created regulations or monitoring criteria, including Massachusetts. They are known to increase the risk of cancer, increase cholesterol, increase the risk of miscarriage by 80-120%, and several other negative health outcomes. According to the National Institute of Health, over 4,700 different PFAS variations have been used in some type of manufacturing since the 1950’s.

Is 20 ppt Safe?

There’s a bit of uncertainty around the “safe level” of exposure to PFAS compounds. There are only a handful of studies that assess associated health impacts, and most agree that more research is necessary to make a determination. In 2016, EPA set a non-enforceable Health Advisory Level of 70 parts per trillion for combined PFOA and PFOS. More recent data suggests that this level is far to high to provide meaningful protection against a range of negative health impacts. A recent study also found that a “safe level” or PFAS could be as low as 0.1 parts per trillion. Although the Massachusetts PFAS standard is on the lower end of state limits, our team would rather see even less PFAS allowed in municipal tap water. 

Not All Water Filters Remove PFAS

If you live in Easton and you’re looking for a solution, it’s important to understand that not all water filters are able to remove PFAS chemicals. Duke University completed a study in 2020 that tested various filtration brands and their ability to remove PFAS from drinking water. The results found that popular brands including Brita and Pur did not do a good job of removing PFAS compounds. Refrigerator filters tested by the Duke research team, including; Samsung, Whirlpool, and GE, also failed to remove PFAS. The full results of this study can be found here. Hydroviv filters are both NSF certified and third-party tested to remove PFAS chemicals. To request our full testing and removal data, please email hello@hydroviv.com.