What is the best option for individual water consumption if we take into
account both health and environmental impacts? The answer to that question,
according to a new study led by the Barcelona Institute for Global Health
(ISGlobal), a center supported by the "la Caixa" Foundation, is that, at
least in the city of Barcelona, tap water is the option that offers more
overall benefits.
The consumption of bottled water has been increasing sharply in recent years
on a global scale. According to previous research, this trend can be partly
explained by subjective factors like risk perception, taste, odor, lack of
trust in public tap water quality and marketing by bottled water companies.
This new study, published in Science of the Total Environment, was aimed at
providing objective data about three different water consumption choices:
bottled water, tap water and filtered tap water. This scientific work has
been carried out in collaboration with the Group of Environmental
Engineering and Microbiology (GEMMA) of the Universitat Politècnica de
Catalunya BarcelonaTech (UPC).
Environmental and health impacts are usually assessed separately due to the
different methodologies applied and resulting outcomes. Environmental
impacts can be estimated with a methodology called Life Cycle Assessment
(LCA), while the consequences in human health are estimated with an approach
called Health Impact Assessment (HIA). This study has tried to overcome this
methodological barrier for the first time by combining LCA and HIA in the
same analysis.
Since tap water quality might differ between cities or countries, the
research team focused in the city of Barcelona, due to the robustness of
available data. The Life Cycle Assessment was conducted using a specific
software and a method called ReCiPe, which allowed researchers to estimate
the damage to ecosystems and to resource availability as well as indirect
impacts in human health derived from the production process of bottled and
tap water. The Health Impact Assessment used data on water consumption
patterns and on levels of chemical compounds in water supply from the
Barcelona Public Health Agency.
Results showed that if the whole population of Barcelona decided to shift to
bottled water, the production required would take a toll of1.43 species lost
per year and cost of 83.9 million USD per year due to extraction of raw
materials. This is approximately1,400 times more impact in ecosystems and
3,500 times higher cost of resource extraction compared to the scenario
where the whole population would shift to tap water.
"Tap water quality has increased substantially in Barcelona since the
incorporation of advanced treatments over the last years. However, this
considerable improvement has not been mirrored by an increase in tap water
consumption, which suggests that water consumption could be motivated by
subjective factors other than quality," says Cristina Villanueva, ISGlobal
researcher and first author of the study.
"One of this subjective factors is the perceived presence of chemical
compounds in tap water. While it is true that tap water may contain
trihalomethanes (THM) derived from the disinfection process and that THMs
are associated with bladder cancer, our study shows that due to the high
quality of the tap water in Barcelona, the risk for health is small,
especially when we take into account the overall impacts of bottled water,"
adds Cristina Villanueva.
In this sense, the results estimate that a complete shift to tap water would
increase the overall number of years of life lost in the city of Barcelona
to 309 (which equals approximately on average two hours of lost life
expectancy if borne equally by all residents of Barcelona). Adding domestic
filtration to tap water would reduce that risk considerably, lowering the
total number of years of life lost to 36.
"Our results show that considering both the environmental and the health
effects, tap water is a better option than bottled water, because bottled
water generates a wider range of impacts," says Cathryn Tonne, ISGlobal
researcher and last author of the study. "The use of domestic filters, in
addition to improving the taste and odor of tap water, can reduce
substantially THMs levels in some cases. For this reason, filtered tap water
is a good alternative. Even though we didn't have enough data to measure its
environmental impact fully, we know it is much lower than that of bottled
water," she adds. However, the authors acknowledge that domestic filtering
devices require an adequate maintenance for a proper performance and to
avoid microbial proliferation.
Reference:
Cristina M. Villanueva et al, Health and environmental impacts of drinking
water choices in Barcelona, Spain: A modelling study, Science of The Total
Environment (2021).
DOI: 10.1016/j.scitotenv.2021.148884
Tags:
Planet and Environment