What is the best option for individual water consumption if we take into account both health and environmental impacts?

15th August 2021

In a study published on 5 July 2021 by Barcelona Institute for Global Health (ISGlobal), the Spanish research group applied data from Barcelona, Spain to answer this question. They evaluated health and environmental impacts of drinking water choices using life cycle assessment (LCA) and health impact (HIA) methodologies.

The evaluation included the next options of drinking water consumption: 1) current drinking water source split; 2) tap water; 3) bottled water; or 4) filtered tap water.

LCA1life cycle assessment

By using LCA they were able to estimate the environmental impacts (like species lost/year and resources use) from raw material extraction and processing, waste generation and disposal, use of electricity, chemicals, and plastic to produce tap or bottled drinking water.

As most of us know, plastic production processes are responsible for non-renewable resource depletion and for the increase of plastic debris worldwide, including microplastics. Growing use of bottled water also contributes to emissions of harmful pollutants for example greenhouse gases into the environment.

Furthermore even in the case of high-energy consuming technologies for drinking water treatments, tap water always shows better environmental performance in terms of global warming potential, compared to bottled water according to Valentina Fantin, researcher of Italian National Agency for New Technologies.

These are the reasons why the scenario where the entire population consumed tap water yielded the lowest environmental impact on ecosystems and resources, while the scenario where the entire population drank bottled water yielded the highest impacts led to approximately 1400 times more species lost/year and 3500 times more resource use (in $).

THM− trihalomethanes

They also estimated the local bladder cancer incidence attributable to trihalomethane (THM) exposure, based on survey data on drinking water sources, THM levels, published exposure-response functions, and disability-adjusted life years (DALYs) from the Global Burden of Disease 2017.

Among the long list of health-relevant chemicals that can be present in drinking water, THMs are an attractive focus for health impact assessment because of widespread exposure in the population through multiple exposure routes.

Virtually the entire population is exposed through inhalation and dermal contact while showering and bathing, in addition to ingestion, and long-term exposure has been consistently associated with increased bladder cancer risk.

Current knowledge indicates that concentrations of trihalomethanes (THMs) are usually higher in municipal than mineral bottled water, although concentrations of THMs were drastically reduced after technological improvements in the drinking water treatment plants in 2009. Annual average concentrations of THMs were above 100 μg/L in some areas prior 2009, decreasing to ≈50 μg/L after 2009.

Meeting drinking water needs using bottled or filtered tap water led to the lowest bladder cancer DALYs (respectively, 140 and 9 times lower than using tap water) in the Barcelona population.

Despite bottled water consumption involves much higher environmental impacts compared to public drinking water supply, global trend shows the popularity of bottled water has sharply increased in the last years worldwide.

Drinking water consumption patterns in the Barcelona population were ascertained from the Barcelona Health Survey (BHS) conducted in 2016–2017 by the Barcelona Public Health Agency (ASPB).

Already in 2006 bottled water was the primary source of drinking water and increased from that year approximately from 54% to 58% until 2016 in spite of the improvements in the quality of the public drinking water supply. This can be explained by factors like risk perception, and the strong marketing behind the bottled water industry.

These findings shows that bottled water consumption could be influenced by the lower trust in public suppliers and the subjective factors due to bad taste, odor, or lime presence- explains Hug March, researcher of Universitat Oberta de Catalunya in his article and continue- that the main reason for bottled water consumption is perception of water chemicals, past health problems.

An alternative in-house water treatment system can replace bottled water when tap water is unattractive because of organoleptic reason.

As conclusion of the study they write−

"Our findings suggest that the sustainability gain from consuming water from public supply relative to bottled water far exceeds the human health gain from consuming bottled water in Barcelona."

The research focused on Barcelona, Spain which is home to around 1.35 million people, but the findings are likely to have relevance for comparable cities in Europe.

As my own stand, the best option is the in-house filtrated water.

1thorough inventory of the energy and materials that are required across the industry value chain of the product, process or service, and calculates the corresponding emissions to the environment.

Szilvia Kullai