We are the paradoxical ape.
Bipedal. Naked. Large-brained. Long the master of fire,
tools, and language.
But still trying to understand ourselves.
Aware that death is inevitable,
yet filled with optimism.
We grow up slowly.
We hand down knowledge.
We empathize and deceive.
We shape the future from
our shared understanding of the past.
CARTA brings together experts from
diverse disciplines to exchange insights on who we are,
and how we got here.
An exploration made possible by
the generosity of humans like you.
Good afternoon. I'm Asher Rosinger
from Penn State University.
Today I'm going to discuss one of
humanity's most pressing problems,
that is, anthropogenic global water insecurity.
Throughout human evolution, water needs have played
an important selective pressure affecting survival.
We've developed several genetic
adaptations to water scarcity,
including changes to our body proportions
to more efficiently used water.
Yet these biological adaptations
are costly in the last resort.
Humans first use behavioral adaptations
to meet their immediate water needs,
which have increased our ability to
survive in extreme environments.
Yet globally, 2.1 billion people lack
access to safely managed
drinking water within 30 minutes of their house.
Water insecurity can manifest in three primary ways.
First, water scarcity or living in places
without enough water and
lack infrastructure to deliver that water.
Second, living in places with
too much dirty water where
reliance on surface water is common.
Finally, places dealing with
water contamination or aging and failing infrastructure.
Water insecurity is defined as
the inability to access and benefit from sufficient,
reliable, and acceptable
water for well-being and a healthy life.
The majority of research has
assessed how water insecurity
is associated with
psycho-social stress and mental well-being.
Discussed is suffering for
water and suffering from water.
While newer research indicates that
it's also associated with physical health.
We care about water insecurity because this has
critical implications for health and
human biology throughout the life course,
and how these problems can compound over one's life.
During infancy, water insecurity can increase
risk of dehydration, diarrhea, and stunting.
In childhood, there's evidence it affects dehydration,
altered gut microbiome, and cognitive performance.
During pregnancy and lactation,
water restriction may lead to higher stress,
and affect fetal homeostatic thirst set points
as well as lead to smaller fetal body size,
which may point to intergenerational effects
of water insecurity.
In adulthood and late adulthood,
proxies of water insecurity
are associated with kidney function,
blood pressure, and food insecurity,
which are some of the leading causes of
morbidity and mortality worldwide.
How individuals and households cope
with water insecurity is critical to understand.
Water is one of humanity's greatest limiting factors.
Therefore, humans and water insecure environments
must use behavioral adaptations
to meet their water needs.
For example, in water scarce environments,
people often rely on
multiple water sources and
may spend hours fetching water.
Yet the very interventions
often from external actors aimed
at addressing water insecurity
may have unintentional consequences.
Today I'm going to focus on three case studies of
these different types of water problems and how
human or anthropogenic changes can
unintentionally further
disrupt water insecurity and health.
First, I want to turn to Northern Kenya to
discuss an emerging water
insecurity issue around the globe,
which is increasing salinity content of groundwater.
The Daasanach, are a
pastoralist population that live near
the banks of the saline Lake Turkana
and are highly marginalized.
One of the biggest concerns for
Daasanach that they expressed to me was
that the salinity of their water was increasing
and that the water salinity can
make them and their livestock sick.
In fact, one of their wells in
a dry riverbed is named El Chuchumbi,
which literally means the salty riverbed
so they have a history of knowing it's salty.
We found that 93% of households are water
insecure and that water salinity is associated with that.
Development projects in the area have
worked to increase water access for Daasanach,
particularly in the main town,
through the construction of deep wells,
stand pipes, and pumps.
But often, these tap into
deeper groundwater which are more saline
or they're built in vulnerable regions
like dry riverbeds and during the rainy season,
they can flood, and break within a matter of months.
We've been tracking the water salinity in this region
along with blood pressure
and kidney function of Daasanach,
to understand how the salinity of water sources are
changing and are associated
with their blood pressure and kidney function.
The guidelines for dietary salt intake
have been established by the World Health Organization,
suggesting that humans shouldn't consume
more than five grams per day.
But there are no similar guidelines released
for safe salinity levels in drinking water,
except that sodium levels above
200 milligrams per liter are unacceptable to taste.
While water with greater than 500 milligrams per
liter is no longer considered freshwater.
Our water quality results indicate
that nearly all of the water sources for
Daasanach are above 200 milligrams per
liter at which you can taste the salinity,
and we found that the hand dug wells range
from 200 to 500 milligrams per liter.
However, the stand pipes in the region had
levels as high as 2,000 milligrams per liter,
which people reported drinking
if there were no other options present.
They also told us that they use this water for cooking,
so they're ingesting it in that way.
When we examine how water salinity is
associated with high blood pressure or hypertension,
we found that each additional 100 milligrams
per liter of salt concentration in
their drinking water was associated with
45 percent higher odds of hypertension.
We also found that
the overall probability of hypertension was quite high in
this population when you take into account
their low BMIs and active lifestyles.
Similarly, we examine the odds of hyper-dilute urine,
which is an indicator of kidney dysfunction.
We've found that each 100 milligrams per liter of salt in
water was associated with
33 percent higher odds of dilute urine,
which was significant in most models.
But we need additional biomarkers
to confirm this finding.
The key takeaways from
this first case study are that it's critical to take
stock of water quality and
the local hydrology prior to interventions,
as the easier water to access in
this region like the tap water was highly saline.
What happens when you increase
access to saline water is that it can have
unintended consequences by increasing
blood pressure and having
implications for kidney function.
Shifting to a second case study of
a situation of too much dirty water.
I want to now focus on lowland Bolivia and the Tsimane,
a group of about 17,000 forager
horticulturalists who I've been working with since 2009,
and who traditionally have used
surface water sources to meet their water needs.
The Amazon is a water-rich environment,
but frequent flooding, intermittent droughts,
fires, and mining all jeopardize
water security and can reduce trust in water sources.
Development and engineering projects have
worked to reduce reliance on surface waters.
Yet 30-60 percent of
these new water sources are inoperable at a given time,
causing frustration and continued
reliance on surface waters,
leading to water insecurity.
The joint monitoring programs,
drinking water services ladder,
classifies water sources along a gradient
to indicate the relative safety and access.
At the bottom is surface water or
water directly from rivers, ponds, and streams.
All the pictures I'm showing are
from Tsimane water sources.
Next on the drinking water ladder
is unimproved water sources,
which is water from unprotected wells or springs.
Next we have what we classify improved water sources,
which have the potential to deliver safe water,
like taps and protected wells.
The further classification then depends on
their distance from a person's home
and their availability.
I wanted to understand what happens to
chronic stress when new water sources are introduced.
We tested how differences in
water source access as
defined by the drinking water ladder,
relate to an objective biomarker of chronic stress.
We hypothesized that chronic stress would
decrease as you moved up the drinking water ladder.
We classified household's access to
water sources and we collected hair samples,
which we analyze for
hair cortisol concentration as
a biomarker of chronic stress.
In contrast with our hypothesis
of an inverse relationship,
the drinking water services ladder showed
a distinct pattern with hair cortisol concentration.
Compared to surface water,
men using unimproved services had
55 percent higher hair cortisol concentration,
while improved water services were
not different from surface water.
Women showed the exact same
distinct pattern where women using
unimproved services had
46 percent higher hair cortisol concentration.
Why are unimproved sources
associated with higher stress than surface water,
which is ranked as lower and less clean water source
on the drinking water ladder?
Well, unimproved sources for Tsimane like open wells,
often lead to frustration because they
can get contaminated and need cleaning.
Here, a man is shown inside
a well getting black gunk out of the well.
He told me that this process of
cleaning the well took three full days.
Yet community members have been told repeatedly by
NGOs that wells are
a cleaner source of water than river water.
This may generate confusion that could exacerbate stress.
Women often complained that
kids in the villages would throw trash
and batteries into the open wells
and that debris would fall into them.
Others said that when they would reach a well,
they'd be unable to extract water
because the water drawing bucket was missing,
further leading to stress.
The key takeaways from
the second case study is that half measures to address
water insecurity can have
unintended consequences like
increasing frustration and stress.
Second, that equity is critical in
development projects in provision of clean water.
Households living farther away from
the construction of improved water sources,
may experience increased stress
and perceptions of disadvantage,
especially if they no longer believe the river is clean.
Finally, turning to the last case study
in the United States,
the issue of whether people can trust
their water is increasingly important,
where access to water that meets
water quality standards often falls along race,
ethnicity, and socioeconomic boundaries.
High visibility events like boil water advisories and
shocks like national attention
to the Flint Michigan water crisis,
may create long lasting distrust of tap water.
I've been examining how did
the Flint water crisis
affect tap water avoidance in the US?
What are the unintended consequences of this event?
When we examine national representative trends
in tap water avoidance among
US children and adults from
the National Health and Nutrition
Examination Survey data,
we see two things.
First, we see huge disparities
in who avoids tap water with
Hispanic and black children and adults
not drinking tap water more
than white individuals over time,
often because of structural inequalities,
systemic racism, and growing distrust.
Second, after the Flint water crisis in 2013,
'14, there was a large uptake in
tap water avoidance following this event.
Overall, this translates into 20 percent or
61 million people in
the US who don't drink their tap water.
Why this matters is that
when people don't trust their water,
they're more likely to avoid it.
Concurrently, we see large shifts to
exclusive reliance on bottled water
in the US since the Flint water crisis.
This has substantial environmental costs
through single-use plastics,
as well as being orders of magnitude more expensive,
leading to higher socioeconomic stress.
Further, we found that those who don't drink plain water
consumed twice as many calories
from sugary drinks as water drinkers.
This is bad because
sugary drink consumption is associated with weight gain,
diabetes, obesity, and dental cavities.
Taking all three of these case studies into account,
it's important to remember that
as we modify our environment,
we change our water supplies.
This results in changes to our exposures.
When individuals respond to water insecurity,
it's critical to be mindful to provide
solutions that understand local hydrology,
cultural customs, and address distrust.
Otherwise, the very solutions we're trying to
implement may have unintentional consequences,
like shifting consumption toward less healthy options,
more saline water or even sugary beverages.
All of these factors can make
water problems worse in the long term.
I'd like to thank my collaborators and
co-authors on the studies I discussed,
the funding agencies, the
participants and the great research teams,
and the organizers.
Thank you.