1. CE 3231 - Introduction to Environmental Engineering and Science Readings for This Class: O hio N orthern U niversity 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.

2. Exposure Assessment  pathways of exposure  calculating CDI

3. Lecture 32 Partition Coefficents and Modeling Risk (Risk III)

4. Risk & Risk Assessment  Topics Covered Include:  New Chemicals Review  Risk Models  Partitioning Coefficients  Octanol water  Vapor pressure

5. New Chemicals Review Program New Chemicals Review Program – Premanufacture Notice US Environmental Protection Agency Office of Pollution Prevention and Toxics Toxic Substance Control Act – Section 5 Program Goal Serve as a “gatekeeper to help manage the potential risk from chemicals new to the marketplace.”

6. New 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

7. New 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)

8. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -10 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow (logP): Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry'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

9. New 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

10. New 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 1.Shake Flask Method 2.Slow Stir 3.Generator Column via HPLC

11. New Chemicals Review Program Octanol/Water Partitioning Non-experimental Estimation Methods 1.Fragment/segment summation 2.Correlations with molecular descriptors (shape, volume,…) with known chemistries 3.Correlations with Reversed Phase HPLC Retention Times of known chemistries 4.3 dimensional structure

12. New 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

13. New 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

14. New Chemicals Review Program Vapor Pressure drives partitioning of compound between atmosphere.

15. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -10 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry'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

16. Putting Numbers into Context logP considered a problem when logKow > 5 (will bioaccumulate) logP from 2 to 5 considered likely to bioaccumulate logP from 0 to 2 potential to bioaccumulate

17. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -60 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST Putting Values into Context

18. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -60 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry'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 bioaccumulate logKow from 0 to 2 potential to bioaccumulate

19. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -60 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST Putting Values into Context

20. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -60 deg C Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 Type : EXP Vapor Pressure: Value : 210 mm Hg Temp : 25 deg C Type : EXP Henry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C Type : EST Putting Values into Context

21. CAS Number : 000105-55-5 Chem Name : n-boulanger Mol Formula: StRuCtUrE Mol Weight : 186 Melting Pt : -60 deg C LIQUID Boiling Pt : 128 deg C Water Solubility: Value : 0.01 mg/L LOW SOLUBILITY Temp : 37 deg C Type : EXP Log Kow: Value : 3.57 LIKELY TO BIOACCUMULATE Type : EXP Vapor Pressure: Value : 210 mm Hg VERY HIGHLY VOLATILE Temp : 25 deg C Type : EXP Henry's Law Constant: Value : 6.85E-004 atm-m3/mole Temp : 25 deg C MODERATELY VOLATILE Type : EST Putting Values into Context

22. Fate considers reactions too! 1.Biologically mediated degradation 2.Hydrolysis 3.Photolysis (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

23. Putting Numbers into Context logP considered a problem when logKow > 5 (will bioaccumulate) logP from 2 to 5 considered likely to bioaccumulate logP from 0 to 2 potential to bioaccumulate

24. New Chemicals Process 1.Gatekeeper for new chemicals 2.Dependent upon partitioning 3.Physical/chemical properties key 4.Modeling 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?...”