Arsenic in Water
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Transcript of Arsenic in Water
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Arsenic in Drinking Water
Huei-An Chu (Ann)
ET450 Environmental Regulation
11/09/2006
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Sinister Uses for Arsenic King of poisons
Victorian ladies of fashionused arsenic for cosmeticpurposes, as well as forkilling husbands.
In the 15th and 16th
century, the Borgias usedarsenic as their favoritepoison for politicalassassinations.
In WWII, arsenic used as awar gas Contact with the skin
produced huge blistersSource for this slide and the following some:
www.epa.gov/safewater/arsenic/pdfs/arsenic_training_2002/train1-background.pdf
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Arsenic poisoning isthought to beresponsible for thedeaths of some wellknown historicalfigures such as:
Claudius Pope Pius III and
Clemente XIV
Charles FrancisHall
Napoleon
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Was Napoleon Poisoned?
A toxicological study ofNapoleon's hair showedmajor exposure, and Istress 'major', to
arsenic." Natural upper limit of
arsenic concentration inhair is one nanogram
per milligram of hair. In one of the samples
tested, the concentrationwas 38 nanograms.June 1, 2001
CNN.com/world
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Arsenic (As)
Semi-metallic element
The metallic form (0 valence): no adversehealth effects
Toxic level: inorganic (As3+ > As5+) > organicform
Focus: inorganic arsenic
Mobile in the environment
The primary medium: water
Pharmaceutical usage for acute promyelocyticleukemia (APL): arsenic trioxide (As
2
O3
)
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Acute Health Effects
typically > 1,200 microgram per liter in water
abdominal pain
vomiting
diarrhea
muscular weakness and cramping
pain to the extremities
erythematous skin eruptions
swelling of the eyelids, feet, and hands
shock
death
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Chronic Health Effects (Arsenicosis)
Non-Cancer
Vascular effects, such as Blackfoot
Disease
Skin lesions, such as skin pigment,hyperkeratosis, and ulcreations
Others: cardiovascular, pulmonary,
immunological, and neurological and
endocrine (i.e. diabetes) effects
Cancer Skin cancer
Internal Cancers (bladder, liver, lung, kidney, colon, uterus,prostate, stomach, nasal passages, )
Mechanism: Arsenic may be a potent endocrine disruptor,
altering hormone-mediated cell signaling at extremely lowconcentration.
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Arsenic Occurrence
Natural source: erosion, dissolution or weathering from rocks or
soils volcanic eruption and forest fires
the dissolved arsenic enters groundwater orsurface water
primarily found in ground waters
Anthropogenic sources: industrial processes, such as mining, smelting,
wood preserving, pesticide spraying, agriculture,
pulp and paper production, coal burning
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Exposure Routes
Ingestion through DrinkingWater
higher in groundwater thanin surface water
from wells drilled througharsenic-bearing sediments
Primarily inorganic form
Inhalation of Air
mostly from occupational exposure
Food Intake
seafood, meat and poultry, grain and grain products,fruits and vegetables
primarily organic form
Primarily inorganic form
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Global Arsenic Concentration in Ground Water
Country Potential ExposedPopulation
Concentration (ppb)
Bangladesh 30,000,000 5,000
Taiwan 100,000 to 200,000 10 to 1,820
Inner Mongolia 100,000 to 600,000 1 to 9,900
Chile 400,000 100 to 1,000
USA and Canada - 100,000
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Arsenic Mass Poisoning in
Bangladesh and West Bengal Epidemics of cholera,
dysentery, and other
waterborne infectious diseasesb/c of bacteria.
Too many children were dying.
In the 1970s, the UnitedNations Childrens Fund(UNICEF), spearheaded aneffort to switch the regionspopulation from drinkingsurface waters to groundwater.
10 Millions tubewells weredrilled into arsenic-rich
sediments
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Arsenic Mass Poisoning in
Bangladesh and West Bengal (Cont.)
As a result, in many of these
wells arsenic levels reach5001,000 g/L and evenhigher.
More than 500 million people
(80% of Bangladeshis) at riskof chronic arsenic poisoning
The World HealthOrganization (WHO) has
labeled this the worst masspoisoning in history.
The need for alternative watersource.
Film trailer: http://www.ifilm.com/ifilmdetail/2745238
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Table Sources: Allan H. Smith et al (2002), Arsenic Epidemiology andDrinking Water Standards, Science, Vol. 296, pp 2145-2146.
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Arsenic Rulemaking
The US EPA made the new arsenic rule in 2001.
Lowers maximum contaminant level(MCL) from 50 to 10 g/L
Establishes maximum contaminant level goal(MCLG) at 0
Applies to Community water systems (CWSs)
Non-transient non-community water systems (NTNCWSs)
Not applied to Transient Non-Community Water System (TNCWS) Becomes enforceable on January 23, 2006
Base on arsenic cancer risk assessment,
considering technological feasibility (economicanalysis)
1
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USEP
A2001
USEP
A2001
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Regulating with Sound Science
EPA promotes sound science research and itsappropriate integration into regulatory policymaking.
Internal Science Advisory Board
Science Policy Council
peer review policy
specially trained staff
External oversight from committees in both congressional chambers
scrutiny from a multitude of scientific and technical
organizations Arsenic case: more scientific review
new evidence and data
expert panels review
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Arsenic Cancer Risk Assessment
Animal evidences and models are absent.
Based on epidemiological data from Taiwan
Skin cancer Internal cancers (bladder, lung, kidney, and lever)
Incidence per 10,000 People
Controversial because of uncertainty and variability
issues
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Uncertainty Issues in Arsenic
Case Limitations of Data from Taiwan
Study design Differences between Taiwan and U.S.
populations, e.g. genetics, lifestyles,
nutrition, diets
Dose-response models
Inconsistent epidemiological data
Low-dose extrapolation incomplete knowledge of the uptake,
bio-transformation, and distribution of
arsenic in the body
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Variability Issues
The risks to sensitive and susceptible
subpopulations may not be fully quantified
people with poor nutritional status
infants or children
pregnant and lactating women
Considering variability and uncertaintyissues in risk assessment, policy has to
apply a Margin of Safety.
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Arsenic Cost-Benefic Analysis
Economic analysis does not support EPAs new arsenicrule.
Table source: Burnett and Hahn (2001), A Costly Benefit, Regulation,
Fall, pp.44-49.
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What are the benefits of this rule?
protect approximately 13 million Americans served byCWSs and NTNCWSs
Prevent
~ 19-31 cases of bladder cancer ~ 5-8 deaths due to bladder cancer per year
~ 19-25 cases of lung cancer
~ 16-22 deaths due to lung cancer per year
substantial non-quantified
benefits of this rule, including
reducing the incidences ofnon-cancerous effects.
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How many people and how many systems
will be affected by this rule?
Table source: http://www.epa.gov/safewater/arsenic/regulations_techfactsheet.html
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How much will this rule cost?
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A Case for Decentralized Standard Setting?
The dilemma in setting anational standard whenthere are striking variations
in costs across waterdistricts.
exemptions provisionunder the Safe Drinking
Water Act Because the differences in
costs and preferencesacross various
communities, the best wayto accommodate suchvariation is to allow districtsto determine their ownstandards. Do you agree?