projects.nytimes.com/toxic‐waters

That Tap Water Is Legal but May Be Unhealthy, CHARLES DUHIGG,  December 16, 2009 

“The 35‐year‐old federal law regulating tap water is so out of date that the water Americans drink can pose what scientists say are serious health risks — and still be legal. Only 91 contaminants are regulated by the Safe Drinking Water Act, yet more than 60,000 chemicals are used within the United States.”

HOW CAN WE TELL IF WATER HAS BEEN TREATED PROPERLY?

Indicator Bacteria

Source: Stefan Walston and Kelley Riley, UA SWES

TYPES OF WATERBORNE PATHOGENS

Viruses Bacteria ParasitesWhat is the definition of a pathogen?

A pathogen is something that causes a disease

Source: Stefan Walston and Kelley Riley, UA SWES

MICROORGANISMS

• Three types:

• Bacteria – E. coli, Salmonella, Vibrio cholera

• Viruses – rhinovirus, norovirus, rotavirus

• Parasites – Cryptosporidium, Naegleria

• Pathogens cause disease. These microorganisms can also be shed in the feces of humans and animals.

Source: Stefan Walston and Kelley Riley, UA SWES

KEEP IN MIND…

• Not all bacteria present a health risk

• Most will not make you sick, but some may

• Low infectivity rates

Source: Stefan Walston and Kelley Riley, UA SWES

ENTERIC PATHOGENS• Exposure is via ingestion

• Primary site of infection is gastrointestinal tract

• Gastroenteritis symptoms• nausea• vomiting• diarrhea• fever

• May spread to other sites (blood, liver, nervous system)

• Shed in fecal material

• “Fecal-oral” route of transmission

Source: Stefan Walston and Kelley Riley, UA SWES

INDICATOR MICROORGANISMS

• Total coliforms – ferment lactose and produce gas at 37°C:• Citrobacter• Klebsiella• Enterobacter• Escherichia

• Fecal coliforms – ferment lactose and produce gas at 44.5°C (body temp.):• Escherichia • Klebsiella

• Indicates fecal contamination if fecal coliforms are present; could also indicate pathogens are present; used as a water quality indicator. E. coli is used as a national standard by water utilities for drinking water and wastewater quality.

Source: Stefan Walston and Kelley Riley, UA SWES

Total Coliforms

Fecal Coliforms

E.coli

Pathogens

Escherichia coli (E.coli) is a bacterium naturally found in the intestines and the feces of warm-blooded animals.

Commonly used as an indicator of fecal pollution of water.

Many different types of E. coli, most harmless, but some may cause illness

(e.g. foodborne outbreaks caused by E. coli O157:H7)

WHAT IS E. COLI ?

WHAT DOES E.COLI LOOK LIKE?

Water Reuse• Many potential uses• “Toilet to tap” do little to 

reassure public qualms• Essentially done already, 

indirectly• Requires greater 

vigilance• May not treat all sources 

of contamination

Wu, UCR, 2009

Chlorination

* 403k from Milwaukee, 1993

http://www.cfour.org/wp-content/uploads/2012/03/Disinfection-Practices.pdf

The danger of abandoning chlorination

A stark example of the continuing public health threat from waterborne disease outbreaks occurred in Peru in 1991, where a major causative factor was inadequate drinking water disinfection. The result: a five‐year epidemic of cholera, the disease’s first appearance in the Americas in the 20th century. The epidemic spread to 19 Latin American countries, causing more than one million illnesses and 12,000 deaths.

EPA: the acute health risk due to enteric disease agents is fouror five orders of magnitude greater than the chronic exposure risk from THMs.

Norovirus Outbreaks – mostly food‐related

http://www.cdc.gov/norovirus/trends-outbreaks.html

Disinfection Byproducts – DBP’s

Cancer on Tap, Fleckenstein, 2001• The risks of drinking chlorinated water …• …regulations reflect an accommodating view toward organochlorines.• …industry officials and regulators operate with an innocent until proven 

guilty prejudice.• …the Morris study found disinfection by‐products in chlorinated water to 

be responsible for 9% of all bladder cancers and 15% of rectal cancers in the U.S. This translates into 10,000 deaths.

• …pregnant women with high exposure to chlorinated drinking water nearly doubled their risk of miscarriage, from a rate of 9.5% to 16%

• The effect of all the factors (genetic, diet, exposure to other pollutants) in addition to the one under study, such as chlorinated drinking water, tends to obscure causal relationships. 

• …it is important to recognize that the EPA did not set the standard for disinfection by‐products in drinking water based only on their health effects.

Is 10,000 deaths accurate?

• Bladder cancer kills 14,880 people annually• Colon/rectal cancer kills 51,690 people/yr

National Cancer Inst.(seer.cancer.gov/statistics)

• 14,880 * .09 = 1,339• 51,690 * .15 = 7,753 sum=9,092Other factors

– Smoking:  OR = 4.2– Coffee (>4 cups): OR = 3.3

Odds ratio: OR ~ ad/bc = 1880/80 = 23.5 (used in Case-controlled studies)

(used in Randomized-controlled studies)

EPA has taken a series of steps …Differences between the Rules

Stage 1• Establishes limits:• Chemical disinfectants:

– maximum residual disinfectant level goals (MRDLG) and

– maximum residual disinfectant levels (MRDLs) for Cl2, ClO2

• Disinfection byproducts:– maximum contaminant level 

goals (MCLGs) and – maximum contaminant levels 

(MCLs) for total trihalomethanes, haloaceticacids, chlorite and bromate

Stage 2• Tightens compliance 

monitoring• Evaluate distribution 

systems for high risk areas• Site specific – locational 

running annual average (LRAA)

• Who: – Comm. Water Services > 25 pers.– Nontransient CWS, >25, > 6 mo

Stage 1

EPA Stage 2 DBP Rule Compliance Deadlines

What are the Costs & Benefits?EPA estimates that implementation of the Stage 1 Disinfectants and Disinfection Byproducts Rule will resultin:1- As many as 140 million people receiving increased protection from DBPs.2- 24 percent national average reduction in TTHM levels.3- Reduction in exposure to the major DBPs from use of ozone (bromate) and chlorine dioxide (chlorite).

The total annual cost of the rule is about $700 million. EPA believes that the benefits exceed the costs of theStage 1 Disinfectants and Disinfection Byproducts Rule. An estimated 115 million households are affectedby the Stage 1 Disinfectants and Disinfection Byproducts Rule. EPA estimates that 95 percent of thehouseholds will incur additional costs of less than $1 per month on their water bills. An additional fourpercent will pay between $1 and $10 per month more, and one percent are expected to incur increasedwater bills of $10 to $33 per month, if they choose to install treatment. However, many of these systemsmay chose less costly non-treatment options, such as consolidation. The majority of households incurringthe highest costs are small systems serving less than 10,000 people that have never been regulated forDBPs.

Quantified benefits estimates for the Stage 2 DBPR are based on reductions in fatal and non-fatal bladder cancer cases. EPA has projected that the rule will prevent approximately 280 bladder cancer cases per year. Of these cases, 26% are estimated to be fatal. Based on bladder cancer alone, the rule is estimated to provide annualized monetized benefit of $763 million to $1.5 billion. The rule applies to approximately 75,000 systems; a small subset of these (about 4%) will be required to make treatment changes. The mean cost of the rule is $79 million annually. Annual household cost increases in the subset of plants adding treatment are estimated at an average of $5.53, with 95 percent paying less than $22.40.

Cost‐Benefit Process

Benefit• Based on Willingness‐to‐pay (WTP) for given risk reduction

• Value of Statistical Life (VSL) ~$7.4 M/SL/yr• Value of Mortality Risk (VMR) $/μrisk/pp/yr

Fracking: Chemicals, Cancer, and Relative Risks, Energy Policy 3/27/12

Consider benzene:• Abundant in nature, urban, oil/gas environ.• Risk threshold: 10 cancers/1,000,000 or .001%

– assumes lifetime exposure– most conservative value (3x higher might be OK)

• for drinking water, 10 ppb; MCl set to 5 ppb• Pavillion, WY case: 49x MCL or .02%, but from deep GW well; 

short‐lived, annual less than .005%• Consider geographic effects of air pollution: .005%(nation), 

.008% Denver, .002% WY so WY total might be ~ .007%

US Death Rates2009 Per 100,000

Heart disease 195 or 25% or 600k

All Cancers 185

Lung disease 45

Hypertension 42

Accidents 38

Alzheimer’s 26

Brest cancer 23

Auto 14

Poison 10

Homicide 5.5

Bladder cancer 4.4

EPA risk reduction target

1.0

Pyne, SWH, 2006(6)

Aquifer Storage – general reduction

Westerhoff, SWH 5(6), 2006

• Most THM form within the treatment plant

• All disinfectants oxidize NOM in water

• The rate and extent of DBP formation are higher as TOC, bromide, temperature, disinfectant dose, and contact time with the disinfectant increase.

• THM4 = 0.0412[TOC]1.098[Cl2]0.152[Br‐]0.068 [Temp]0.609[pH]1.601[Time]0.263

• Standards must be met at each sampling location on a running annual average basis.

TypicalDist. Sys.

SpringEvent

Singer, SWH, 2006(6)

Pharmaceuticals

Pharmaceuticals in our water

Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams, 1999−2000: A National Reconnaissance, Env. Sci & Tech, 2002, 36 (6), pp 1202–1211Dana W. Kolpin, Edward T. Furlong, Michael T. Meyer, E. Michael Thurman, Steven D. Zaugg, Larry B. Barber, Herbert T. Buxton

* “Previous research has shown that even low‐level exposure (<0.001 íg/L) to select hormones can illicit deleterious effects in aquatic species”

80%

*

“The results of this study document that detectable quantities of OWCs occur in U.S. streams at the national scale. This implies that many such compounds survive wastewater treatment and biodegradation”

Kolpin, et al, 2002

Desalination

utminers.utep.edu/omwilliamson/hueco_bolson.htm

wrri.nmsu.edu/publish/watcon/proc49/hutchison.pdf

Hydrofracking

Source: ProPublica, www.propublica.org/

Carbon Sequestration

Superfund Sites

projects.nytimes.com/toxic‐waters

Debating How Much Weed Killer Is Safe in Your Water Glass CHARLES DUHIGG, August 22, 2009 

Arsenic Concentrations

Pesticides ‐model