2.7 avery environmental case fracking final - acmt in the hydraulic fracturing process. ... the...

$: 2.7 Avery Environmental Case Fracking final - ACMT in the hydraulic fracturing process. ... the House Comm. on Energy and Commerce published a list of 750 chemicals used in fracking—650$
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Presented by: A Nelson Avery, MD, FACMT, FACOEM

Board Certified in Toxicology, Occupational Medicine, and Internal Medicine

Associate Dean, Texas A&M Health Science Center College of Medicine Professor and Director Preventive Medicine Residency Program

[email protected] 1

Environmental Toxic Tort Case:

A Nelson Avery, MD 2

Disclaimer Slide

I do not have any actual or potential conflicts of affiliation or financial interest in relation to this program.

This presentation will not use or mention any off-label, unlabeled, or investigational use of products or devices.

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Ques8ons to Ask When You Get a Request to Provide Expert

Tes8mony for an Environmental Toxic Tort Case •  WHO: How many people involved? Will I be seeing all

of them, or just a subset? What other experts? •  WHAT: Was the exposure agent(s) known? Single

agent or mixture? Known agent or novel? •  WHERE / WHEN / HOW MUCH

•  Where was the exposure? What was the pathway? How long had the person(s) lived there?

•  How long were they exposed? One exposure or repeated—acute vs. chronic?

•  Was the exposure level known? If not, will someone be doing modeling?

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Discussion on Fracking

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Fracking in Unconven8onal Reservoirs •  Hydraulic fracturing (AKA, fracking) is a

well stimulation technique used to maximize production of oil and natural gas in unconventional reservoirs: –  Shale rock formation are found in many locations

across the US. Shale gas was 14% of the total US supply in 2009, and is projected to be 45% by 2035.

–  Coalbed methane makes up only 8% of the total natural gas production.

–  Tight sands (gas-bearing, fine-grained sandstones or carbonates) accounted for 28% of production in 2009.


Shale Sites in US

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Gas Shale in Appalachian Basin

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San Antonio Houston

Austin

Laredo Corpus Christi

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Drilling •  To drill into shale, often at great

depths (1-3 miles), the rock must be fractured with high pressure water (2000 to 20,000 m3), with fine sand and chemicals to prevent the fractures from closing, to unlock the trapped gas and oil.

•  To access these formations, drillers use a combination of horizontal drilling and higher volume fracturing. The “toe” may be up to 2 miles away from the horizontal leg.

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EPA

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Well Construc8on •  A drilling string is composed of a

drill bit, drill collars, and a drill pipe. •  A drilling fluid such as a water- or

oil-based liquid (“mud”) is circulated down the drilling string. The liquid typically contains water, barite, clay, and chemical additives.

•  Casings are steel pipes that line the borehole. They prevent the hole from caving in and confined the fluids to the wellbore.

•  Once the casing is inserted in the borehole, it is cemented in place.

EPA


Fracking •  After the well is constructed, the targeted

formation is hydraulically fractured to stimulate natural gas production.

•  This requires large volumes of water (with-drawn from a source and transported to the well site).

•  The water is mixed with chemicals and a proppant (a granular substance, most commonly sand, that is carried in suspension by the fracturing fluid and serves to keep the cracks open when the fracturing fluid is withdrawn).

•  Production casing is perforated by explosive charges.


Resulting fractures create pathways in otherwise imperm-eable gas-containing formations resulting in gas flow to the well for production.

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Fracking Water Cycle: 5 Stages

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EPA


•  Large volumes of water are withdrawn from ground water and surface water resources to be used in the hydraulic fracturing process.

•  For shale wells, 2-4M gallons of water are typically needed per horizontal well.

•  Source water is typically stored in 20,000-gallon portable steel tanks.

•  Potential Impacts on Drinking Water Resources

• Change in the quantity of water available for drinking

• Change in drinking water quality

Stage 1: Water Acquisi8on


•  Once delivered to the well site, the acquired water is combined with chemical additives and proppant to make the hydraulic fracturing fluid.

•  Total volume of fracturing fluid is 15,000 to 60,000 gallons for a shale gas well.

•  Potential Impacts on Drinking Water Resources

• Release to surface and ground water through on-site spills and/or leaks

Stage 2: Chemical Mixing

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Chemical Mixing

EPA


Types of Addi8ves In 2011, the House Comm. on Energy and

Commerce published a list of 750 chemicals used in fracking—650 listed as potentially harmful and 22 as carcinogens.

Proppants: crystalline silica, ceramic balls Strong acids: HCl Friction reducing agents: polyacrylamide, mineral oils Surfactants: 2-butoxyethanol, isopropanol Clay stabilizers: KCl, tetramethylammonium chloride Gelling agents: Bentonite, guar gum, hydroxy-

ethylcellulose


Types of Addi8ves Scale inhibitors: ethylene glycol, propylene glycol pH control agents: sodium carbonate, potassium

carbonate, ammonium chloride Holding gels: hemicellulase, ammonium persulfate,

quebracho Crosslinker (maintenance of fluidity with increased

temperature): sodium perborate, borates, acetic anhydride

Iron control: citric acid, EDTA Corrosion inhibitors: quinoline derivatives,

dimethylformamide, propargyl alcohol Biocides: dibromoacetonitrile, glutaraldehyde

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•  Pressurized hydraulic fracturing fluid is injected into the well, creating cracks in the geological formation that allow oil or gas to escape through the well to be collected at the surface.

•  Important to consider the proximity of drinking water wells, production wells, abandoned wells, injection wells, and under-ground mines.

•  The chemical identity of the injected chemicals may change because of chemical reactions in the fluid under high pressure and heat.

•  Potential Impacts on Drinking Water Resources •  Release of hydraulic fracturing fluids to ground water due to

inadequate well construction or operation •  Movement of hydraulic fracturing fluids from the target formation to

drinking water aquifers through local man-made or natural features (e.g., abandoned wells and existing faults)

•  Movement into drinking water aquifers of natural substances found underground, such as metals or radioactive materials, which are mobilized during hydraulic fracturing activities

Stage 3: Well Injec8on

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Fractures and Well Damage •  During the fracturing

process, fractures can be produced, which can spread unpredictably underground, have broken into adjacent wells, and can travel up to 2500 feet horizontally.

•  This can allow migration of native brine, fracturing fluids and hydrocarbons from the new wells, which can potentially infiltrate older bores and rise back up to the level of drinking water aquifers closer to the surface.

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EPA

Pipe failure

New fractures


•  When pressure in the well is released, hydraulic fracturing fluid, formation water, and natural gas begin to flow back up the well. This combination of fluids, containing hydraulic fracturing chemical additives and naturally occurring substances, must be stored on-site—typically in tanks or pits—before treatment, recycling, or disposal.

•  Estimates of fracturing fluid recovered vary from 25 to 75%.

•  Flowback can have high concentrations of several ions (barium, bromide, calcium, iron, magnesium, sodium, strontium) and radionuclides.

•  Potential Impacts on Drinking Water Resources • Release to surface or ground water through spills or

leakage from on-site storage

Stage 4: Flowback and Produced Water (Hydraulic Fracturing Wastewaters)

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Fracturing Wastewater •  The fluid that returns to the surface can be

referred to as either flowback or produced water, or collectively as “hydraulic fracturing wastewaters.” –  EPA considers “flowback” to be the fluid

returned to the surface after hydraulic fracturing has occurred, but before the well is placed into production.

–  “Produced water” is the fluid returned to the surface after the well has been placed into production.


•  Wastewater is dealt with in one of several ways: –  disposal by underground injection (primary method in all

major shale areas except Marcellus Shale), –  treatment at POTWs followed by disposal to surface water

bodies, or –  recycling (with or without treatment) for use in future fracking

operations.

•  Potential Impacts on Drinking Water Resources •  Contaminants reaching drinking water due to surface

water discharge and inadequate treatment of wastewater—POTWs may not be able to handle increased dissolved solids and radionuclides

•  Byproducts formed at drinking water treatment facilities by reaction of hydraulic fracturing contaminants with disinfectants (chlorinated and brominated DBPs)

Stage 5: Wastewater Treatment & Waste Disposal

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Case Study

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Case Study •  WHO: 1 family •  WHAT:

–  Alleged exposure to fracking chemicals. –  They were unable to get information on

chemicals used in fracking other than MSDSs—so the exact composition could only be assumed.

•  WHERE / WHEN / HOW MUCH –  Exposure occurred at their home. –  Route of exposure was through groundwater

contamination à inhalation, dermal and GI absorption.

–  Exposed for 9 months. –  No sampling done during the height of their

illness. A Nelson Avery, MD

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Case History •  In 200X and 200Y, a company drilled and

hydraulically fractured (“fracked”) 3 natural gas wells on the case family’s private property.

•  Within 2300 feet of the newer wells, there were 2 preexisting gas wells (from 1940 and 200X).

•  By spring 200Y, the case family noted their home water (from a well) turning brown and they experienced health changes.

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Map of Case Study

A Nelson Avery, MD

Case House

Neighbor’s House

New Wells 200X-200Y

Breakout into aquifer

Hydraulic fractures

Hydraulic fractures

Cracked or absent cement casing

1940 old well

200X prior well

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Case History •  After the drilling company tested their water,

the family was told in fall 200Y to cease using the water in the house.

•  They had used their well water for drinking, bathing, washing clothes, and cooking. They started using bottled water for drinking, but they continued to use the water for all other purposes.

•  In late winter-early spring 200Z the drilling company paid for them to move into a motel, and their health improved.

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Next Steps •  Take a complete history and physical

•  Standard medical hx (including family, social, military, extensive ROS)

•  Occupational / environmental hx

•  Review all available medical records, expert reports, depositions

•  Go through risk assessment process: 1. Hazard identification 2. Dose-response assessment 3. Human exposure assessment 4. Risk characterization

A Nelson Avery, MD


Hazard Iden8fica8on

First step is hazard identification §  Review and analyze toxicity data §  Weigh the evidence that a substance causes

various toxic effects §  Evaluate whether toxic effects in one setting

will occur in other settings

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Hazard Iden8fica8on Factors to take into account on hazard: §  physical and chemical properties §  patterns of use §  source and route of exposure §  control measures §  magnitude, duration and frequency of

exposure §  physical nature of exposure conditions §  populations exposed §  information derived from human exposures


Minimal Risk Levels •  An MRL is defined as an estimate of daily human

exposure to a substance that is likely to be without an appreciable risk of adverse effects (noncarcinogenic only) over a specified duration of exposure.

•  MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration within a given route of exposure.

•  MRLs can be derived for acute, intermediate, and chronic duration exposures for inhalation and oral routes. Appropriate methodology does not exist to develop MRLs for dermal exposure.


Maximal Contaminant Levels •  MCLs are standards that are set by the US EPA for

drinking water quality. An MCL is the legal threshold limit on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act. The limit is usually expressed as a concentration in milligrams or micrograms per liter of water.

•  To set a Maximum Contaminant Level for a contaminant, EPA first determines how much of the contaminant may be present with no adverse health effects. This level is called the Maximum Contaminant Level Goal (MCLG). MCLGs are non-enforceable public health goals. The legally enforced MCL is then set as close as possible to the MCLG.

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List of MSDSs •  Cl-14: methanol (<68%), propargyl alcohol (<5%) •  Clay Treat-3C: tetramethyl ammonium chloride

(40-60%) •  GBW-12 CD: hemicellulase enzyme •  FAW-5: butoxyethanol (<10%), methanol (<20%),

ethyl alcohol (<15%), aqueous ammonia (<10%) •  Ferrotrol 300L: citric acid (40-70%) •  Flo-Back 30: surfactant

•  GW-3LDF: petroleum distillate blend (60-70%), guar gum (30-40%)

•  Hydrochloric acid (3-36%)


MSDSs •  Inflow-102: methanol (20-22%), 2-butoxyethanol

(12-16%), isopropanol (1%) •  LT-32: isopropyl alcohol (<20%), oxyalkylated

alcohol (<20%), methanol (<5%) •  Magnacide 575: tetrakis(hydroxymethyl)-

phosphonium sulfate (60-100%) •  S-8C, sand, 100 mesh: silica (100%) •  BRABUF: magnesium oxide (60-100%)

•  BARAZAN D Plus: xanthan gum (60-100%)

•  CLAYFIX-II Material: alkylated quaternary chloride (30-60%)


MSDSs •  CLAYSEAL Plus: hydrochloric acid (1-5%),

propylene glycol (10-30%), polyalkeneamine (10-30%)

•  DEXTRID LT: 5-chloro-2-methyl-4-isothizolin-3-one (<0.1%), complex carbohydrate (60-100%)

•  GasPerm 1000: isopropanol (10-30%)

•  Graphite (60-100%) •  LUBRA-BEADS Coarse: polymer

•  Potassium Chloride (60-100%)

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Dose-‐Response Assessment Second step is dose-response assessment §  Involves extensive review of toxicological and

epidemiologic literature to ascertain if can construct dose-response curves for end-points.

§  Where on the continuum of the dose-response curve an adverse human health effect is likely to occur.

§  It is a quantitative relationship. §  Need a mathematical model.


Human Exposure Assessment Third step is human exposure assessment §  Evaluate sources, pathways, magnitude

(measured or estimated concentrations), duration of exposures, and doses.

§  Examine monitoring data from air, soil, water, and biota.

§  Measure biological fluids for presence of metal/chemical if still consuming contaminated groundwater; check biomarkers of effect.

§  Use mathematical modeling for gaps in knowledge.


Human Exposure Assessment •  Determine dose—defined as the amount of

toxicant that reaches the target tissue over a defined time span (“dose” = exposure1 x time). Total dose = Contaminant concentration x Contact rate (frequency) x Exposure duration x Absorption fraction2

÷ Body weight (kg)

1: In occupational and environmental environments, exposure is often used as a surrogate for an internal dose.

2: Estimating systemic absorption should include consideration of absorption rates; but data on absorption are limited for most substances; so absorption is not always included in dose estimation (i.e., by default, it is usually considered complete).

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Human Exposure Assessment Human exposures are calculated using standard

intakes: §  average 70 kg human §  drinking 2 liters of water daily §  breathing 20 cubic meters of air daily §  ingesting 100 mg of soil daily §  life span of 70 years § work lifetime of 45 years


Causation §  The toxicologist should analyze whether the disease

can be related to chemical exposure by a biologically plausible theory (general causation).

§  Was the plaintiff exposed to the chemical in a manner that can lead to absorption? [direct measures vs. modeling]

§  A differential diagnosis is the method of considering all relevant potential causes of a plaintiff’s symptoms and eliminating alternative causes based upon physical examination, clinical tests, and a thorough case history. Look for alterative causes of health and exposure.

§  Was the dose to which the plaintiff was exposed sufficient to cause the disease (specific causation)?


Have to Consider Other Sources and Pathways of Groundwater Contamina8on

•  Natural •  Environmental •  Agricultural •  Storage and Handling of

Chemicals •  Waste Disposal Systems

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Natural Contamina8on •  Dissolved solids (500 mg/L) and chlorides

(250 mg/L) – Typically found at seaward end of coastal

aquifers. –  It is common in other aquifers that are

greater than several hundred feet. •  Iron (0.3 mg/L) and manganese (0.05 mg/L) •  Nitrate/ nitrogen (10 mg/L)…if find >3 mg/L

indicates human activity •  Radon


Environmental Contamina8on •  Urban runoff (spills, abandoned industrial sites)

•  Polluted stream infiltration •  Construction excavation (topsoil removed à

loss of natural filtra2on, closer to water table; spills of chemicals and fuel)

•  Cemeteries and animal burials •  Atmospheric (emissions from motor vehicles,

power plants, industries à elevated levels of sulfates, nitrates, heavy metals, asbestos, hydrocarbons)

•  Deicing salts (runoff from salt storage piles and highways à sodium chloride and some calcium chloride)


Storage & Handling of Materials and Wastes •  Leaking underground storage tanks (tanks

corrode; poorly maintained; no leak backup containment; deterioration of abandoned tanks)

•  Gasoline, acids, solvents, other chemicals (gasoline is less dense than water)

•  Transporting (leaking while coupling or from hose breaking and spills—tankard turns over on highway)

•  Pipelines (corrosion, defective welds, displacement by tree roots, vibration from vehicles)

•  Mining (shafts intersect with aquifers; coal + O2 in air à H2SO4; mine tailings ; rapid infiltration of contaminants due to loss of topsoil filtering capacity)

•  Oil well brines (>120,000 brine-disposal impoundments)

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Risk Characteriza8on Fourth step is risk characterization §  The target is a cancer risk value based on

low-dose extrapolation (>1 x 10-6 increase is level of concern)

§  Risk calculation for non cancer risk: Hazard Index (HI)= CDI or ED RfD ED = Superfund site specific exposure dose CDI = chronic daily intake, expressed as a mass of

substance per unit of body weight per unit of time RfD = reference dose (NOAEL ÷ uncertainty and modifying

factors)

If HI >1, risk is assumed to be significant


•  Inquire about the names of all plaintiffs, defendants, and experts to avoid conflict of interest.

•  Know as much as possible about the process that caused contamination and any unique terminology.

•  Consider additive effects: •  ACGIH, NIOSH and OSHA recommend additive

effect for 2 or more substances that affect the same organ/system.

•  Consider the inert ingredients present in a product.

Recommenda8ons


•  Review Social Security records to verify work history.

•  Don’t hesitate to ask a medical librarian to help in a literature search.

•  Write your final report with deposition and a scientific challenge in mind.

•  Be prepared to answer: 1) Did you calculate a dose?; 2) Did you do a differential diagnosis?

Recommenda8ons

2.7 avery environmental case fracking final - acmt in the hydraulic fracturing process. ... the...

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