I need help in my assignment

Chemical, Biological and Environmental Engineering

ENGR221:

The Science, Engineering and Social Impact of Nanotechnology

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Risk Management

Decision-making process to address & prioritize hazards identified through risk assessment Evaluation & selection of alternatives for mitigation -no further action -engineering controls -environmental mitigation -remedial/financial actions

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Name of the Risk Assessment Company - optional Your Name Report date Parts of the risk management report: I. Background and applications of the nanotechnology Uses of the nanomaterials Boundaries of the risk assessment (type of assessment?, who

is at risk?) II. Hazard and exposure identification Dose response and toxicity evaluation – you must justify using

a surrogate material (absorption?, distribution? metabolism? excretion? toxicity?)

Exposure assessment (who?, how?, how long?, routes? III. Risk characterization Risk management strategy (think about all of the influences on

risk management) Evaluation and selection of alternatives for mitigation

Risk Management Report

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HOW TO DEAL WITH THE LACK OF DATA: Macro-state materials

Much toxicological knowledge of bulk materials Extrapolates to nano-scale?

Natural UFPs Volcanic smoke Forest fires Desert dust

Anthropogenic UFPs Diesel exhaust Welding fumes Fly ash silica from coal plants

Engineered nanomaterials CNTs QDs Semiconductor particles

Risk Management Report – Final Project

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Risk Management • Hierarchy of controls

– elimination – substitution – engineering controls – administrative controls – personal protective equipment

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Hierarchy of Controls Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

Engineering controls

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Task Duration

Quantity

milligrams

kilograms

15 minutes

8 hours

slurry/suspension highly dispersed

agglomerated

Engineered Local Exhaust Ventilation

Closed Systems

Occupational Health Hazard mild / reversible

severe / irreversible

We need to consider these factors

Courtesy NIOSH

Chemical, Biological and Environmental Engineering

Elimination Why would we eliminate nanoparticles? Why is this the least practical control approach?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

Fullerine nanogears, photo courtesy NASA and Wikimedia

Chemical, Biological and Environmental Engineering

Substitution Is substitution more likely than elimination? What are possible difficulties with substitution?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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Substitution isn’t as easy as it sounds

Each of the solvents above was replaced by another chemical that later proved to pose risks

Courtesy Michael Wilson

Chemical, Biological and Environmental Engineering

Engineering Controls: Modification

What modification could we make to a process to reduce airborne nanoparticles?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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Nanoparticles are often provided and worked in a wet state to reduce

the risks of exposures

Would this crumbling carbon nanofiber paper present less risk if the material were kept wet?

Chemical, Biological and Environmental Engineering

Engineering Controls: Containment

What are some examples of containment for nanoparticles?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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CNTs can be produced in these enclosed furnaces

Photo courtesy NIOSH and Nanocomp Technologies, Inc.

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Broader view of manufacturing containment

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Gloveboxes are a type of containment being used for handling nanoparticles

Air sample

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Glove box at ORNL Nanophase Materials Research facility

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Gloveboxes inside a “Nanoparticle

Containment Room”

Photos courtesy Jitendra S. Tate, Ph.D., Professor, Texas State

University-San Marcos

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Work practices and PPE will still be needed when enclosures are opened

Harvesting SWCNTs from a Carbon Arc Reactor

Chemical, Biological and Environmental Engineering

Engineering Controls: Ventilation

There are two main divisions

1) dilution ventilation 2) local exhaust ventilation

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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Dilution ventilation is okay for nonhazardous exposures, but isn’t

acceptable for nanoparticles

Standard supply diffuser in an office

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Dilution ventilation supplies some outdoor air, but mostly recycles room air. What about the lab?

Graphic courtesy EPA

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Local exhaust ventilation (LEV) controls for more hazardous exposures

New laboratory hoods in U. Puerto Rico

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Lab hoods need to be tested for face velocity and the sash height marked

Any safety issues with this nano research hood?

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Processes have HEPA filters on

exhaust systems

Courtesy Oak Ridge’s Nanophase Materials Research

facility

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With nanoparticles between 20 - 400 nm, 40 nm is the most penetrating size

N-95 P-100

Particle Diameter

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Larger scale controls can work for nanoparticles

Mixing of CNFs inside ventilated enclosure. Air is

drawn underneath plastic strips and

up to ceiling exhaust vents.

Photo courtesy of Mark Methner, PhD, CIH, NIOSH

Chemical, Biological and Environmental Engineering

Administrative Controls: Work Practices

What practices could make a difference?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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NIOSH found that work practices during cleanout made a real difference

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Work practices for cleanup at end of the shift:

• Clean work areas using either a HEPA-filtered vacuum or wet wiping • Clean in a manner that prevents contact with wastes • Comply with all federal, state and local regulations when disposing of

wastes • Wash hands frequently, particular before eating or leaving the

worksite • Wear assigned PPE and keep it maintained properly • Use sticky mats and gowning procedures

Source: NIOSH and Oak Ridge National Laboratory Sticky pads in lab

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Special flooring includes tacky covering and sticky mats

Photos courtesy Jitendra S. Tate Texas State University San Marcos

Sticky mat

Chemical, Biological and Environmental Engineering

Personal Protective Equipment

Why is PPE at the bottom?

Elimination

Substitution

Modification

Containment

Ventilation

Work Practices

Personal Protection

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Personal Protective Equipment Overview

• Body • Hand • Eye • Foot • Respiratory

Level A Level B Level C Level D

Which level do you think we may need for handling nanoparticles?

Courtesy Kirkwood Community College

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Tyvec is the most widely used body covering for nano operations

Photo courtesy EPI Services

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Are protective clothes only worn for worker protection?

Center for Nanophase

Materials Science

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NIOSH recommends wearing hand protection when working with

nanoparticles • Nitrile (most generally used) • Neoprene • Polyvinyl chloride (PVC) • Latex

Nitrile gloves

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Eye protection may also be necessary

Must meet ANSI Z-87.1

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Respirators may be required for some nano operations.

If so, OSHA’s standard (1910.134) would apply

• Written program • Training • Medical evaluation • Fit testing • Respirator

maintenance program

Photo courtesy IUOE Hazmat Program

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NIOSH found no evidence of nanoparticles passing through respirator filters at a higher

rate

U. of MN tested respirator filter media to 3 nm Flat plate tester

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Filtration performance of an example NIOSH approved N95 filtering facepiece respirator

n = 5; error bars represent standard deviations TSI 3160; Flow rate 85 L/min

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EPA requires full-face N-100 cartridge respirators for CNT manufacturers

under consent order, unless they prove no exposure

North Full-face Respirator Courtesy North Corporation

MSA Full-face Respirator Courtesy MSA

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OSHA requires that workers pass a fit test before wearing a respirator

PortaCount Quantitative Fit Testing System Courtesy TSI, Inc.

Quantitative Qualitative

Allegro Complete Smoke Fit Test Kit Photo Courtesy Gempler’s

Both are acceptable. Which is better?

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Air purifying respirators filter out dust and vapors

• Must have the correct color-coded cartridge

• Must be NIOSH- approved

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What type of filter may be needed for nanoparticles?

Color Type

Magenta, purple

High Efficiency Particulate Air (HEPA)

Black

Organic vapors only

Yellow

Acid gases and organic vapors

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Particulate filters are classified based on resistance to oil

• Not resistant to oil N • Resistant to oil • Good for one shift in oil mist R • Oil Proof • Good for prolonged use in mist P

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Particulate filters are further classified based on efficiency

95 percent  designated 95 99 percent  designated 99 99.97 percent  designated 100

(HEPA filter)

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Acceptable for nanomaterial work, unless oil is present

This gives 9 categories of particulate respirators

N R P 100 100 100 99 99 99 95 95 95

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NIOSH has developed a selection logic that can be applied to nanoparticles

http://www.cdc.gov/niosh/docs/2005-100

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For your nano-product: What type of controls will need to be implemented to reduce occupational risk?