Clarke Lecture: How Safe Is Safe in the Treatment of Drinking Water for the Public? - Dr. Trussell
Summary
TLDREl guion del video ofrece una perspectiva histórica y actual sobre la seguridad del agua potable, desde la conexión entre agua contaminada y enfermedades en el siglo XIX hasta los desafíos de las sustancias químicas y orgánicas trazas en la era moderna. Se discuten avances en tratamientos de agua, la importancia de la regulación y la necesidad de un nuevo paradigma para abordar los riesgos emergentes, enfatizando la importancia de la ciencia y la colaboración para garantizar el agua potable seguro.
Takeaways
- 😐 La relación entre el agua potable y las enfermedades se estableció en 1854 por John Snow, quien demostró que un brote de cólera en Londres estaba vinculado al agua de un pozo específico.
- 🔬 Durante el siglo XIX y gran parte del siglo XX, el enfoque en el agua potable se centró en el tratamiento para prevenir enfermedades transmitidas por el agua, como la caries y la fiebre tifoidea.
- 🏭 El desarrollo de la industria química en el siglo XX trajo consigo avances significativos pero también problemas, como la creación de compuestos químicos que persisten en el medio ambiente y en el agua potable.
- 🌐 La publicación de 'Cierto silencio' por Rachel Carson en 1962 marcó un punto de inflexión en la discusión nacional sobre los impactos negativos de ciertos compuestos químicos, especialmente el DDT.
- 🔬 A finales de los 1960, las técnicas analíticas mejoraron significativamente, permitiendo la detección de contaminantes químicos en el agua, incluyendo los productos químicos porosos (BTEX) y los compuestos orgánicos volátiles (VOC).
- 🚰 A lo largo del siglo XX, se implementaron cambios en el tratamiento del agua para prevenir los productos químicos secundarios y se establecieron programas para limpiar las aguas subterráneas contaminadas.
- 📉 La regulación del agua potable se vio influenciada por la Ley de Delany, que buscaba erradicar cualquier cantidad de carcinógenos en los alimentos, lo que llevó a la EPA a establecer límites de calidad del agua (MCL) basados en límites de cuantificación prácticas.
- 🌿 La detección de nuevos grupos de compuestos químicos en las aguas, incluyendo medicamentos, productos de cuidado personal y hormonas, ha elevado preocupaciones sobre la seguridad del agua potable.
- 📉 La tecnología de análisis del agua ha avanzado rápidamente, lo que permite detectar trazas de compuestos químicos a niveles cada vez más bajos, planteando desafíos para determinar cuándo el agua es considerada segura.
- ⚖️ Se sugiere que se necesite una nueva discusión sobre el riesgo y la seguridad del agua potable, considerando la detección de compuestos químicos a niveles cada vez más bajos y la necesidad de un enfoque precautorio.
- 🛡️ Se propusieron cuatro directrices para abordar la nueva era de contaminantes en el agua, incluyendo la preferencia por no tener compuestos químicos人造 en el ambiente, el reconocimiento de que este principio no siempre es factible, la búsqueda de mejoras continuas en el tratamiento del agua y la búsqueda de sustitutos para compuestos persistentes.
Q & A
¿Cuál es la conexión entre el agua potable y las enfermedades?
-La conexión entre el agua potable y las enfermedades se estableció en 1854 por John Snow, quien demostró que un brote de cólera en Londres estaba conectado con el agua tomado de un pozo específico.
¿Qué cambios se produjeron en el tratamiento del agua potable durante el siglo XIX y principios del siglo XX?
-Durante el siglo XIX y principios del siglo XX, el enfoque fue en el tratamiento del agua para prevenir enfermedades transmitidas por el agua, como la fiebre tifoidea y el cólera, mediante la presión continua, la filtración rápida y la clorazione.
¿Qué símbolo se asoció con el agua potable segura en el siglo XX?
-En el siglo XX, el olor a cloro en el agua potable se convirtió en un símbolo de que el agua estaba libre de enfermedades microbianas, representando que una civilización había entrado en la Edad Moderna.
¿Cuál fue el impacto de la industria química en el agua potable?
-El desarrollo de la industria química en el siglo XX llevó a la creación de muchos compuestos que mejoraron la vida cotidiana, pero también introdujo sustancias químicas en el agua, lo que generó preocupaciones sobre la seguridad del agua potable.
¿Qué fue el punto de inflexión en la discusión nacional sobre los efectos de los pesticidas y otros compuestos químicos?
-El punto de inflexión fue en 1962 con la publicación del libro 'Silent Spring' de Rachel Carson, que demostró las consecuencias no anticipadas de ciertos compuestos químicos, en particular el DDT.
¿Cómo se detectaron por primera vez los contaminantes orgánicos en el agua potable?
-Los contaminantes orgánicos en el agua potable se detectaron por primera vez en la década de 1960 gracias a las mejoras en las técnicas analíticas, especialmente el Cromatografo de gases y el Espectrómetro de masas.
¿Qué son los compuestos disinfección por desinfección (DBP) y por qué son importantes?
-Los compuestos disinfección por desinfección (DBP) son sustancias químicas que se forman cuando se utiliza cloro para desinfectar el agua, y son importantes porque pueden representar un riesgo para la salud, a pesar de que se encuentren en niveles muy bajos.
¿Cuál es la relación entre la regulación del agua potable y la 'Ley de la dosis práctica' (PQL)?
-La 'Ley de la dosis práctica' (PQL) es el nivel más bajo que se puede medir de forma confiable, y ha sido utilizado para establecer el nivel máximo contable (MCL) para los carcinógenos en el agua potable, con el objetivo de ser lo más cercano a cero que sea factible.
¿Qué son los compuestos orgánicos emergentes y cómo afectan el agua potable?
-Los compuestos orgánicos emergentes son una nueva clase de sustancias químicas, incluyendo medicamentos, productos de cuidado personal, y hormonas, que se encuentran en niveles muy bajos en el agua potable y que representan un desafío para su tratamiento y regulación.
¿Qué sugiere el discurso para abordar los riesgos asociados con los compuestos orgánicos en el agua potable?
-El discurso sugiere la necesidad de un nuevo enfoque para determinar qué niveles de compuestos orgánicos son aceptables en el agua potable, lo que podría incluir la adopción de un enfoque de precaución, la mejora continua en el tratamiento del agua, y la búsqueda de sustitutos para compuestos persistentes.
Outlines
🧪 La Seguridad del Agua Potable a lo largo del Tiempo
El primer párrafo aborda la perspectiva histórica y tecnológica de la seguridad del agua potable, desde la conexión establecida en 1854 entre el agua potable y las enfermedades, hasta los avances en tratamiento del agua en el siglo XX. Se mencionan figuras clave como Tom Hawkley, George Fuller, John Leal y la lucha contra enfermedades transmitidas por el agua. La introducción del cloro como desinfectante y la reducción en tasas de mortalidad son destacadas como logros significativos, con el olor al cloro considerado un símbolo de agua segura y un paso hacia la Edad Moderna.
🚗 El Desarrollo de la Industria Química y sus Consecuencias
El segundo párrafo explora el desarrollo de la industria química en el siglo XX y su impacto en la vida cotidiana, desde el caucho sintético hasta el DDT y otros compuestos químicos. Sin embargo, también se destaca el cambio en la percepción pública hacia estos compuestos químicos, especialmente después de la publicación de 'Silent Spring' por Rachel Carson en 1962, que resaltó los efectos no intencionados de ciertos compuestos, como el DDT, en el medio ambiente. La aparición de contaminantes en el agua, incluyendo los byproducts químicos causados por el cloro, y la respuesta de la EPA y la sociedad a estos hallazgos se discuten.
🔬 Avances en la Tecnología de Análisis de Agua y Nuevos Desafíos
El tercer párrafo narra el progreso en la tecnología de análisis de agua, especialmente la introducción del gas chromatograph mass spectrometer, y cómo esto ha permitido la detección de contaminantes químicos en niveles cada vez más bajos. Se mencionan los desafíos que representan los nuevos compuestos orgánicos trazables (POCIs) y los compuestos orgánicos volátiles (VOCs), y cómo la ciencia y la regulación han tratado de abordar estos problemas. También se discute la evolución de las políticas de regulación del agua, incluyendo el concepto de nivel máximo de contaminación (MCL) y el límite de quantificación práctico (PQL).
🌐 La Nueva Era de Contaminantes Orgánicos y el Desafío de la Seguridad del Agua
El cuarto párrafo enfatiza la llegada de una nueva era caracterizada por la rápida expansión de la población mundial y el comercio, y cómo esto está impactando el medio ambiente y la presencia de contaminantes orgánicos en el agua. Se discuten los desafíos de evaluar y manejar estos contaminantes en ausencia de una comprensión científica completa de sus efectos, y se sugieren posibles enfoques para abordar estos problemas, como la mejora continua en el tratamiento del agua y la búsqueda de alternativas a compuestos persistentes.
🛡️ La Búsqueda de un Nuevo Paradigma para la Seguridad del Agua
El quinto párrafo aborda la necesidad de un nuevo paradigma para definir la seguridad del agua en la era de los contaminantes orgánicos trazables. Se sugieren cuatro directrices para abordar esta nueva realidad, incluyendo la preferencia por el agua libre de compuestos antropogénicos, la necesidad de un filtro para tomar decisiones antes de que la ciencia esté disponible, la mejora continua en el tratamiento del agua y la búsqueda de sustitutos para compuestos persistentes. Se discute la importancia de un enfoque precautorio y la utilización de criterios de riesgo mínimo para guiar inversiones y regulaciones.
🤒 Los Contaminantes Microbiológicos y su Relevancia en la Seguridad del Agua
El sexto párrafo compara los riesgos de los contaminantes orgánicos trazables con los de los contaminantes microbiológicos, destacando que, a pesar de la baja concentración de los primeros, los segundos, aunque en concentraciones más bajas, pueden tener consecuencias más inmediatas y graves para la salud humana. Se argumenta que, aunque los avances en la detección y tratamiento de contaminantes químicos son importantes, los patógenos siguen siendo una amenaza significativa para la seguridad del agua y merecen una inversión continua en la ciencia y el control.
🏆 Agradecimientos y Reconocimiento de la Trayectoria del Orador
El último párrafo no es parte del discurso principal, sino que es un agradecimiento del moderador por la presentación y un reconocimiento a los premios y a las personas involucradas en el evento, incluyendo a los receptores previos del Premio Clark, a la familia y amigos del orador, y a los patrocinadores y voluntarios que hicieron posible la celebración.
Mindmap
Keywords
💡Tratamiento del agua potable
💡Desinfección
💡Industria química
💡Plomo de cloro
💡Rachel Carson
💡Cromatografía de gases y espectrometría de masas
💡Compuestos orgánicos por desecho
💡Regulaciones del agua potable
💡Riesgo
💡Precaución
Highlights
No man does his work alone, emphasizing the importance of collaboration in achieving success.
The connection between drinking water and disease was established in 1854 by John Snow using maps and interviews.
19th and 20th centuries' focus on water treatment to prevent waterborne diseases like cholera and typhoid fever.
Introduction of key figures in water treatment advancements: Tom Hawkley, George Fuller, John Le, and the role of chlorine.
The rapid decline in death rates due to effective water treatment in the US during the first half of the 20th century.
The Modern Age brought challenges such as the development of the chemical industry and its impact on safe drinking water.
Rachel Carson's 'Silent Spring' highlighted the significant consequences of chemicals like DDT, changing the national dialogue.
The discovery of disinfection byproducts like chloroform and the presence of VOCs in groundwater.
The challenge of determining safe levels of trace organic chemicals in drinking water with limited evidence of health risks.
The implementation of the Superfund program to clean up groundwater and the shift in disinfection methods.
The development of analytical techniques like gas chromatograph mass spectrometer for detecting trace chemicals in water.
The presence of residual drugs, personal care products, and hormones in waterways as a new concern for water safety.
The rapid expansion of detection capabilities for trace organics, suggesting a 'new law' similar to Moore's law for technology.
The need for a new paradigm for safe water due to the impact of population growth and commerce on the environment.
The proposal of four guidelines for managing trace organic chemicals in water, including seeking continuous improvement.
The importance of finding substitutes for manmade compounds that persist in the environment and prioritizing those with health effects.
The comparison between the risks of trace organic compounds and microbiological contaminants in drinking water.
The call for investment in understanding pathogens and their control in water, especially considering potential water reuse.
The summary emphasizing that while trace organic chemicals capture our attention, pathogens remain the most significant health risk in water.
Transcripts
no man does his work alone and I wrote a
little insert that you all have that you
can read at your leisure that talks
about some people that I collaborated
with while I done my work so I won't go
through that any any further here I'll
just if you don't mind I'll just jump
into my my
presentation so so in this talk I'll try
to provide a a long-term perspective on
the issues we face in making water safe
making drinking water safe I'll take us
back in the past to the middle of the
19th century David already did some of
that we'll talk about what happened
since then and then we'll talk about the
New Age The Next Generation must face
the title of the talk is how safe is
safe in the treatment of drinking
water so the connection between drinking
water and disease was established in
1854 by John Snow a noted physician in
Victorian England using maps and
interviews of the effective population
snow connected the collar outbreak in
London at the time through drinking
water taken from the Broad Street
well during 19th century and much of the
20th century that followed the focus in
drinking water then was on the treatment
of water to prevent waterborne disease
diseases like chera in typhoid fever
showing the little organisms that that
we all love that are responsible for
that here are some early Personalities
in that effort I've just picked a few
among many Tom hawkley a civil engineer
in Victorian England who is an advocate
of continuous pressurization of Water
Systems to prevent
contamination George Fuller who
developed rapid Sand Filtration to
purify the water John le the first to
introduce chlorination in the United
States to disinfect the water and able
woman who played a pivotal role in the
adoption of chlorination Nationwide as
as we mentioned
earlier data on the rapid decline of
death rates in the US in the first half
of the 20th century like this CDC data
shown here are often cited to
demonstrate that drinking water
treatment was one of the greatest
engineering achievements of the 20th
century by the 1960 when I graduated
from high school it might even be said
that our Public Health officials took
comfort in just a little bit of a
chlorine smell in the drinking water it
was a sign that their water was free
from microbial
disease that chlorine smell was a happy
moment in fact you could say Safe
Drinking Water became a symbol that a
civilization had made it into the Modern
Age but the Modern Age also brought
other problems with
it safe drinking water was only one of
the great achievements of Science and
Engineering in 20th century another
great achievement was the development of
our chemical industry we invented a lot
of chemicals to make our life easier
Dupont even coined the slogan Better
Living Through Chemistry let me give you
some examples of the important chemicals
that were invented in the first half of
the 20th
century when when rubber was in short
supply we invented synthetic rubber we
still make our tires with it
today I don't have to tell you how
important penan is it was discovered in
1928 but making large quantities was a
very difficult thing to achieve but by
1944 uh in the middle of World War II we
were making millions of doses for our
troops we invented nylon as since
synthetic fiber that replaced silk in
women's stockings Nyon is both tougher
and cheaper than silk I remember when I
was a kid my mother you know nylons were
cheaper than silk stockings but you can
only wear a Silk Stocking once because
they were ruined after
that and nowadays I don't think anybody
wears
some
DDT the miracle pesticide we use it for
everything for lice pests in the kitchen
elm disease mosquitoes I remember my dad
spraying it all over the
place for me personally one of the most
dramatic was the herbicide
daon dond came out in the mid1 1950s
when I was a kid and one of my chores
was to pull the crab grass out of our
dondra
lawn I spent a lot of long hot
summer afternoons in that lawn I grew up
in Southern
California for me
personally well
so then my uncle Amos who was a farmer
told my dad about
daon my dad sprayed daon on the lawn the
stuff killed the grab grass but it
didn't touch the dondra I was sold on
D
the chemical industry as you might
imagine was quite proud of these
achievements this ad from penwal in
1946 or maybe 47 is a good example the
text in the ad Begins the Great
Expectations held for DDT have been
realized during 1946 exhaustive
scientific Studies have shown that when
properly applied DDT kills a host of
destructive pests and is a benefactor to
all of
humanity
and it was
true with all these new chemicals being
as powerful as they
were and with human nature being such
that it is you won't be surprised that
not everyone saw it the same way
chemicals that can produce such
impressive results were naturally
suspect in 1962 a Tipping Point came in
our national dialogue about these issues
when Rachel Carson wrote the book Silent
Spring in that book she demonstrated
that some of the most miraculous of
these manade chemicals DDT in particular
had significant consequences that had
not been
anticipated Carson's book stood the test
of Science and captured the imagination
of the world
Community it was the analytical sciences
that brought the issue to drinking
water in the late 1960s analytical Tech
techniques vastly improved particularly
important was the gas chromatograph Mass
spectrometer using these instruments and
there's one shown here using these
instruments EPA conducted surveys of the
nation's Water Supplies they have found
evidence of chemical spills which they
were looking for but more important they
also found perhaps more important they
also found that when we use chlorine to
disinfect the water it caused chemical
byproducts like chloroform and later on
vol Al organic chemicals which we call
voc's were also found in groundwater
basins all over the
nation when we found these disaffection
btics of vo's we faced some important
decisions on the one hand these
compounds were found at very little
levels we hadn't found them until we had
these fancy
instruments also and this is important
the evidence that they represented a
health risk
was what I call second order science
there was no direct evidence or
certainly very little direct evidence of
Health consequences from Human exposure
rather there was evidence in studies
from animals exposed to much higher
levels of chemicals and that evidence
had to be extrapolated across one
species to another and across orders of
magnitude of concentration and across
Decades of exposure in order to figure
out what what its impact would be
it' be a long time before this issue was
settled
science also the risks imputed were
generally small when compared to the
risks that the population ordinarily
engages in during everyday life the
decisions we make all the
time there were also concerns on the
other side of the Ledger though even
though there was ambiguity about the
level of risk where the customer is
concerned the drinking water customer
the risk is
involuntary so it becomes a matter of
public trust we're making decisions on
behalf of the
public also there was evidence that the
public was concerned about the
issue and finally some important figures
in the industry began to Advocate that
these chemicals be removed Abel wman who
I mentioned before was the one of the
most visible of these figures Abel was
in the late 80s at the time but believe
me he was still very
persuasive so there was a lot of debate
but in the end the nation spent the rest
of the 20th century changing
disinfection to prevent disinfection
byproducts and implementing super uh
super fund program to clean up our
groundwaters
Nationwide so you might ask in light of
all this fuzzy information about the
risks of the chemicals how do we decide
what levels we would
achieve it's important to understand
these regulations written at a time you
can tell I practiced CU it's all
recorded it's important to understand
these regulations written at the time
when the official I look at Washington
DC was still reflected by the Delany
Amendment which was an FDA regulation
that banned any chemicals any chemical
added to food uh which could induce
cancer in
animals so or man man or animals so so
far
carcinogens any amount was unacceptable
no amount was
acceptable so in the operating this
environment EPA proposed an interesting
strategy they proposed an maximum tment
level
goal and a maxent level the max level
was the enforceable level and for
carcinogens the goal would be zero but
the MCL will be set as close to the goal
as feasible but of course there were a
lot of debates about what level is
feasible so to help this resolve this
issue in the debate EPA offered that an
important consideration determining
what's feasible would be the Practical
quantification limit which would be the
lowest level that you could reliably
measure so the lowest feasible level for
an MCL would then be the
pql so from that time on all carcinogens
the M the MCL has been set at
pql in essence through the artifice of
this practical modification limit we set
a goal of Zero no contamination can be
measurable but as a nation struggle to
address Vault organic chemicals and dvps
as we went on in those decades to deal
with it the science of Water Analysis
continued to advance in 1997 just as we
approached the end of the 20th century
German
scientists uh reported the presence of a
new group of chemicals in um European
rivers and streams and then 2002 the um
us Geological Survey published a
national uh study showing these same
chemicals were widespread in US
waterways as
well some of these chemicals were
residual drugs we take to protect our
health and that we then pass on the
environment and our urine other these
residuals of personal care products like
perfume insect repellant or
sunscreen caffeine and coffee others
were natural hormones like estradiol
or e or synthetic hormones like ethanal
esile which we take for birth control
some are sweeteners we use to sweeten up
our sugar-free soft drinks like um
sucrose or Ace sulfane
K now we had a new thing to worry about
these emerging chemicals occur at the
part P trillion level a thousandfold
lower than the dpps and V's we found
four decades ago again the levels are
low enough it's hard know the best
course of
action as we work to meet this challenge
it's becoming clear that we're resolving
it will require resources more than just
our drinking water industry it may
require that we build a new consensus
about what it means to have safe
water these Trace organic chemicals I
would
argue in our environment are harbingers
of a new age that we're now entering
this new age has two characteristics
that are important to understand the
first is the rapid expansion of the
Earth human population which is having
impacts that um are Beyond those we've
experienced before and the second is
that even more rapid impact or expansion
of worldwide
Commerce as the level of our Commerce
continues to increase along with our
population indeed much faster than the
population increases the detrus of our
civilization uh will become increasingly
present in the environment around us
Trace organic chemicals and drinking
water are only one form this debris
takes we see evidence of in the smog in
Southern California that started to
appear in the late 40s early 50s we saw
evidence of acid rain in the
70s the ozone layer in the 80s and of
course the global warming we talked
about earlier
today but where drinking water is
concerned it is the accumulation of the
trans organic chemicals in water that
has become the big
issue for the moment our strategy
continues to be to treat them below the
levels of detection and we've got some
great Hardware to do
it but the Improvement of SC of the
science of Water Analysis is rapid and
inexorable so we're able to find this
chemical detrius our civilization at
lower and lower levels in increasingly
at places we've never been able to find
them before for since
1970 I would argue analytical technology
has been the fastest growing area of
water
science this chart shows a crude plot of
the history of detection from measuring
ter Organics and water during the course
of my career and well beyond the idea is
we can make our own equivalent of Mo's
law so you know Mor was the guy who said
that the number of transistors on a
microchip doubles every two years well
you know you could say say that our new
law will be the detection of Trace
Organics drops by half every 2 and A2
years and so if you plot that out we'll
be one picogram per liter by the
2035 one molecule per liter by the end
of the century I don't know where we'll
go after
that so what does it
mean well increasingly I think we know
something is there when we don't know
what it's being there at that level
means
so the question is when is the water
pure when is it
safe this leads us I think to an
essential question in this new age do we
need some kind of new discussion about
risk about when water is
safe but we have problems discussing
risk over the past four decades here in
the US we have developed them refined a
formal risk assessment process to help
us address these unknowns
scientific reviewers have weighed in
weighed in many of them U much brighter
than I many times and a lot of formal
procedures have developed for testing
and extrapolating the test data from lab
animals to people from Days of exposure
decades exposure from exposure of GRS
per leader to exposure picr per leader
and so
on but our risk assessment process can't
keep up with the new chemicals being
generated by Commerce
the process is too low slow and it's too
expensive we're finding ourselves with
an increasingly longer list of
unregulated chemicals unknown
significance as a result inadequate
guidance is presently available to help
the public gain perspective on these
chemicals we operate from the
perspective of
fear to address this dilemma the
Europeans have adopted a precautionary
approach much like the approach we took
the dpps when amble woman weighed in
three decades
ago
necessarily essentially the principle
states that evidence of harm rather than
definitive proof of harm should prompt
policy but of course it's much more
complicated than that and too much
precaution would prevent uh progress and
we certainly don't want to PR progress
so the whole idea is pretty
controversial this cartoon I think does
a good job of capturing the
extremes some would say Europe has
carried precaution to an
extreme how might we achieve better
balance I'd propose four guidelines we
could consider in this new era one I
think we all have to agree we prefer
that we we not have these manmade
chemicals in our environment or in our
drinking water that's the place to start
second we should recognize that this
first principle is not universally
achievable therefore we need a screen to
help us make intelligent investment and
decisions before the subtle science is
available and third in the treatment of
drinking water and waste water we should
seek continuous
Improvement implementing affordable uh
broadspectrum treatment technology as
they become
available and fourth we should find
substitutes for manmade compounds that
persist through our treatment processes
when I say we I don't mean our industry
I mean our nation we need to find
substitutes like we did for detergents
like we did for C uh
cfc's but those things that persist on
water environment and we should give
priority to those that have demonstrated
health
effects I said we need some kind of
screen to help us guide us in our
investments I think perhaps the Minimus
risk would be
useful place to start with that screen
of course the problem is that while we
all agree on the principle of dious risk
or dominous things there's often strong
disagreement as to what level of risk is
in fact dominous so the specifics are
not something we just resolve with signs
it has to be decided by some excepted
Authority a regulator a court of law
perhaps the national
eies but there's Reason for Hope our
Regulators already use a variety of
diminish criteria in managing
risk and Regulators also in the world do
also as an example the FDA generally
a lifetime risk of one million as
the Minimus in their
regulations more than that over the past
five or six decades the developed world
has built a sophisticated
infrastructure of cons uh for the
consideration of Minimus risk where
chemicals are concerned and these are
reflected in guidelines advice
advisories regulations regarding human
exposure to chemicals medicines
agriculture food water in a number of
different
areas and they're used by recognized
authorities like the EPA FDA wh The
Institute of medicine and it it seems to
me that perhaps these could serve as a
launching point for a more comprehensive
set of the Minimus
criteria so what about those
microbiological contaminants we started
with when we began our efforts on water
treatment 160 years ago are they
important
anymore this chart shows the top eight
illnesses in the US this compiled by CDC
all but one are gastrointestinal
diseases that are that could be
transmitted by water today these
diseases are primarily spread in food
and person person
contact but it's pretty evident there
are still plenty of gastro in testal
diseases around in the population and
getting them in our drinking water would
be a great way to spread them around to
a lot more people and um this is what
seems like is going to happen in the
Philippines the next several
weeks I propose to take a moment to go
through the exercise of characterizing
these organisms as Trace organic
compounds torqus that were designed by
nature and and try to Prov a little bit
of of an engineer perspective on this by
comparing them with the the trace
Organics that nature has made with the
trace Organics we've made so this fellow
was refreshing himself with a nice glass
of water let's compare how the presence
of two chemicals might affect him first
let's look at ndma nitrosol De methyl
mean this is a man-made chemical EP has
on its contaminant canidate list
California's Public Health goal is 3
nanog per L 3 *
10us uh G per
lader so let's compare ndma to the neuro
virus neuro virus is the most common
cause this top thing on that list I
showed you uh the elding 50 the the dose
that would cause half of us to get sick
is about 2700 genome copies so say 2700
molecules now let's put these an
equivalent basis first ndma 3 nanog is
about 2.4 * 10 1 1 molecules per
ler and then neur virus so um in
molecules that's about it's 2700
molecules per liter for the ld50 so that
comes
to 2.2 * 10-7 GS per
liter can might suggest we use moles per
liter now I ask you to note the
concentrations for ndma on the left are
about all about 8 to 10 orders of
magnitude lower
than the concentrations for for the nor
virus higher I'm sorry higher
than higher than the con for neuro virus
that's that means they're 100 million to
10 billion times
different now let's look at the
consequences first ndma estimates are if
you're exposed to three NR of ndma and
you're drinking water every day for 70
years you're chance of getting cancer
increases by 1 in a
million remember your chance of getting
cancer is about 1 in four
anyway if you happen to
be one of those one a million uh your
the Fate is yours alone the rest of your
family will be just fine their risks are
still just one
four for n of us if you drink this water
the con ation and with this conation
norovirus in it you have 50/50 chance of
48 Hours of acute gastroenteritis get a
bed we're talking the full circuit thing
intense vomiting explosive di you'll be
sitting on the L with your head in the
sink and in the following days unless
your hygiene is near
superhuman several members of your
family will have the same
experience so as I pointed out earlier
by all men measures of concentration
ld50 for neuro virus is 100 to 10
million times lower than the con the
Minimus concentration for neuro virus
yet the consequence exposure to the
neuro virus seem awfully
unpleasant I think this is special
caution for poal
reuse if if we believe poal reuse in our
future and I I believe it is we need to
continue to invest in our understanding
in the science of pathogens and their
measurement and control because it's
going to be the most important thing we
worry
about so let me summarize our old
Paradigm for Safe Water was to use
natural water sources unaffected by the
activity of
man TR organic compounds we're now
seeing in our water are har dangers of a
new age where the growth of population
and commerce and improvements in endal
chemistry make that natural water
Paradigm
unworkable where to organic compounds
are concerned we need a new paradigm for
Safe Water ultimately
conventional regulations need to be
expanded to address this sort of thing
but in the meantime benchmarks might
exist do exist which might be used to
develop the Minimus
guidelines finally it's the trace
organic chemicals that capture our
imagination but I think it's the
pathogens that are the most important
health risk thank
you
I I don't know if I take questions or
we're
done if someone has a question be if if
you do um I apologize won't be able to
see your hands all I can see is the
light in my
face
questions or
comments good J good job
w
rhs congratulations Clark Prize
recipient so I do want to uh turn your
attention to the the card that rhs had
written and it's in your program
and what I thought was in interesting
about the pro the uh the note was the
number of people that you acknowledged
uh Perry Perry mccardy Mike Kavanaugh
Larry Leong Isham n n who are here
previous Clark prize recipients Jim
Morgan Charlie Amilia George sabag gloss
John criten who's here Carrie how who is
here um but you mentioned your family
and Liz it's been great to get to know
you over the years and thank you for
coming and it's great to have you here
Shane and Brian thank you and your wives
Seline and Lindy who haven't met but
thanks it's good to have you here and um
I want to uh thank Jim Swindon uh as
always and Morton Smith it's good to
have you here representing the
foundation and your families it's good
to have you here uh the Joan Irvine
Smith and Nal Richard G Clark Foundation
has been a great suppor of NWI for over
20 years now and we truthfully honestly
appreciate that support I want to thank
again the trussle family for attending
all the previous Clark PR Clark priz
recipients it's great to have you come
back every year I don't know if people
tell you that but it is it's great to
see you and I want to mention endur
staff Brandy Gina and Roxanna we
couldn't do this without
you we had great support from our
volunteer students as always you're
always welcome
and I want to mention our nwri agencies
we had a number of board members come
and that's fantastic it was good to have
you here so thank you for a great
evening I appreciate all you coming and
we'll see you next year thank
you
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