to Environmental Engineering and Science Readings for This Class O hio N orthern U niversity Introduction Chemistry Microbiology amp Material Balance Water amp Air Pollution ID: 759590
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Slide1
CE 3231 -
Introduction to Environmental Engineering and Science
Readings for This Class:
Ohio Northern University
Introduction
Chemistry, Microbiology & Material Balance
Water & Air Pollution
Env
Risk Management
Partition Coefficients and Modeling
Real data characterizing risk is difficult and expensive to come across. As thousands of chemicals enter the market place each year, models help estimate the risk based upon compound structure and physical-chemical properties. Here, we examine how partition coefficients are used to make decisions.
Slide2Exposure Assessment
p
athways of exposure
c
alculating CDI
Slide3Lecture
32
Partition
Coefficents
and Modeling Risk
(Risk
III)
Slide4Risk & Risk Assessment
Topics Covered Include:New Chemicals ReviewRisk ModelsPartitioning CoefficientsOctanol waterVapor pressure
Slide5New Chemicals Review Program
New Chemicals Review
Program –
Premanufacture Notice
US Environmental Protection AgencyOffice of Pollution Prevention and ToxicsToxic Substance Control Act – Section 5
Program GoalServe as a “gatekeeper to help manage the potential risk from chemicals new to the marketplace.”
Slide6New Chemicals Review Program
Risk Evaluations
Risk Based
- potential health risks - toxicological investigations
Exposure Based
- potential exposure risks - chemical property investigations - fate modeling: ranks outcomes I to IV
Slide7New Chemicals Review Program
Physical/Chemical Properties
Estimate Concentration in Water
Estimate Absorption through skin, lungs and GI
Estimate Bioconcentration
Estimate Risk to Human Health and the Environment
Estimate Migration through Soil to Groundwater
Estimate Toxicity
Boiling Point
Vapor Pressure
Estimate Concentration in Air
Estimate Inhalation Exposure
Estimate Henry
’
s Law Constant
Estimate Volatilization from water
Water Solubility (estimate)
Octanol/Water Partition Coefficient (Kow, P)
Melting Point
Estimate Removal in Wastewater Treatment
Soil/Sorption Coefficent (Koc) (estimate)
Slide8CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -10 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow (logP): Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
N-boulanger is used to formulate air fresheners.
Illustrating Example
Slide9New Chemicals Review Program
Octanol/Water Partitioning
Reported as log
Kow
or log P
Used to estimate water solubility, soil sediment adsorption, biological absorption (dermal, oral, GI, inhalation), bioaccumulation, and toxicity model for partitioning within body
Slide10New Chemicals Review Program
Octanol/Water Partitioning
80% of PMN process is determined through use of log
Kow
- fuels QSARs (Quantitative Structural Activity Relationships) or EPA
’s ECOSAR (Ecological Structural Activity Relationship) used during the evaluation
Experimental Determination
Shake Flask Method
Slow Stir
Generator Column via HPLC
Slide11New Chemicals Review Program
Octanol/Water Partitioning
Non-experimental Estimation Methods
Fragment/segment summation
Correlations with molecular descriptors (shape, volume,…) with known chemistries
Correlations with Reversed Phase HPLC Retention Times of known chemistries
3 dimensional structure
Slide12New Chemicals Review Program
The Agency
prefers experimentally derived
Kow values. Whenever non-experimental methods will be estimated, the
most conservative value will be used!
Log Kow drives partitioning between the substance and biological tissues
Slide13New Chemicals Review Program
Vapor Pressure
rate of vapor condensation = vaporization rate of liquid
determined experimentally through automated instruments, an isoteniscope, or gas saturation procedure
strongly hints at air fraction
can be correlated for most compounds
Slide14New Chemicals Review Program
Vapor Pressure drives partitioning of compound between atmosphere.
Slide15CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -10 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
N-boulanger is used to formulate air fresheners.
Putting Values into Context
Slide16Putting Numbers into Context
logP
considered a problem when
logKow > 5 (will bioaccumulate)logP from 2 to 5 considered likely to bioaccumulatelogP from 0 to 2 potential to bioaccumulate
Slide17CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -60 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
Putting Values into Context
Slide18CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -60 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
Putting Values into Context
logKow considered a problem when logKow > 5 (will bioaccumulate)logKow from 2 to 5 considered likely to bioaccumulatelogKow from 0 to 2 potential to bioaccumulate
Slide19CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -60 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
Putting Values into Context
Slide20CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -60 deg CBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 Type : EXPVapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST
Putting Values into Context
Slide21CAS Number : 000105-55-5Chem Name : n-boulangerMol Formula: StRuCtUrEMol Weight : 186Melting Pt : -60 deg C LIQUIDBoiling Pt : 128 deg CWater Solubility: Value : 0.01 mg/L LOW SOLUBILITY Temp : 37 deg C Type : EXPLog Kow: Value : 3.57 LIKELY TO BIOACCUMULATE Type : EXPVapor Pressure: Value : 210 mm Hg VERY HIGHLY VOLATILE Temp : 25 deg C Type : EXPHenry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C MODERATELY VOLATILE Type : EST
Putting Values into Context
Slide22Fate considers reactions too!
Biologically mediated degradationHydrolysisPhotolysis (direct or indirect)
New Chemicals Review Program
All the models EPA uses to determine reactions are based upon the physical/chemical parameters reported in the PMN
Slide23Putting Numbers into Context
logP
considered a problem when
logKow > 5 (will bioaccumulate)logP from 2 to 5 considered likely to bioaccumulatelogP from 0 to 2 potential to bioaccumulate
Slide24New Chemicals Process
Gatekeeper for new chemicalsDependent upon partitioningPhysical/chemical properties keyModeling approach
New Chemicals Review Program
“
…we
’
re busy alright. I can send you home with about 500 submissions right now. Do you have a U-Haul?...
”