1. W. Tyler Mehler PhD Student Research Summit 18.8.2016
Development of freshwater whole-sediment toxicity identification evaluation (TIE) techniques for use in aquatic systems in Australia
W. Tyler Mehler
PhD Student
Research Summit

2. Clean Water Act and WET Testing
1984: “Whole Effluent Toxicity” test and Chemistry of “Priority Pollutants” Required
Limitation in defining causality of toxicity:
All Chemicals Cannot be Accounted for
Potential for Complex Mixtures
“Toxicity” Approach

3. Late 80s to early 90s – TRE/TIE guidance developed in Duluth, MN
Development of TIE
Late 80s to early 90s – TRE/TIE guidance developed in Duluth, MN

4. What is a TIE? Toxicity Identification Evaluation = TIE 10% Mortality
Conduct Toxicity Test
Adjust water for organics
70% Mortality
Organic Contaminated Water
No Change
Adjust water for ammonia
Conduct Toxicity Test
The same Organic Contaminated Water
Adjust water for metals
Conduct Toxicity Test
No Change

5. Matrix Choice Problems: Overlying Water & Pore Water
Issues with surface water TIEs:
Many contaminants are hydrophobic, contaminants are not in surface water
Pore water
Sediment grain
Issues with pore water TIEs:
Bioavailability
Ingestion
Water quality parameters
Environmental Realistic?
usgs.gov

6. Add organics amendment
Sediment TIEs
10% Mortality
Conduct Toxicity Test
Add organics amendment
Organic Contaminant
70% Mortality
No Change
Add ammonia amendment
Conduct Toxicity Test
Organic Contaminant
Organic Contaminant
Add metals amendment
Conduct Toxicity Test
No Change
Organic Contaminant

7. TIE Method ?? Test Species: Chironomus tepperi
Austrochiltonia subtenuis
Spiked Contaminants:
Ammonia
Copper
Permethrin
Endpoints:
Mortality
Growth (via dry weight) ??

8. 1.54 NA 3.92 TIE Method for Ammonia ?? Test Species:
Chironomus tepperi
Austrochiltonia subtenuis
Spiked Contaminants:
Ammonia
Copper
Permethrin
Endpoints:
Mortality
Growth (via dry weight) NA
3.92 ??

9. TIE Method for Cationic Metals
1.70
Test Species:
Chironomus tepperi
Austrochiltonia subtenuis
Spiked Contaminants:
Ammonia
Copper
Permethrin
Endpoints:
Mortality
Growth (via dry weight)
3.15
5.23 ??

10. TIE Method for Permethrin
4.52
Test Species:
Chironomus tepperi
Austrochiltonia subtenuis
Spiked Contaminants:
Ammonia
Copper
Permethrin
Endpoints:
Mortality
3.02
Growth (via dry weight)
In Progress ??

11. TIE Method for Permethrin
Test Species:
Chironomus tepperi
“When this technique was explored with freshwater organisms in 10-day tests (measuring survival and growth), some problems with reduced growth and/or survival occurred at higher levels of charcoal addition.” – US EPA TIE guidance (2007)
Austrochiltonia subtenuis
Spiked Contaminants:
Ammonia
Copper
Permethrin
Endpoints:
Mortality
Growth (via dry weight) ??

12. Aim #2: Understanding the limitations of charcoal-based amendments for TIE purposes.
“…we have tended to emphasize the growth endpoint in TIE work with C. dilutus and would recommend using it even if the sediment causes mortality of C. dilutus at higher concentrations. In selecting the sediment dilution to be used in a TIE based on C. dilutus growth, we generally select a dilution that exerts a strong growth effect (e.g. 75% inhibition of growth) without causing substantial mortality.” – US EPA TIE guidance (2007)
Maul et al. 2008

13. Resolving the Activated Carbon Issue
Emergence
Survival B a a a
Growth (as a function of weight) is sediment-specific.
Activated carbon at higher concentrations affected both weight and mean development.
Emergence (and survival) not affected by additions of activated carbon.
Is emergence more sensitive than growth for midges? 1 a 1 1
1,2 b b
1,2 2 C 1
1,2
1,2
1,2 a 2
a,b a a a 2 b
Males
Females

14. Next Steps on improving TIEs:
Specific TIEs for novel chemicals that may not be removed by traditional means (i.e. Spinosad).
Rapid TIE techniques (i.e. fish embryos).
Application in field.

15. Folks at FilChem and Castle Mountain Zeolite
Questions?
Acknowledgements:
CAPIM and Biosciences
You Jing and Li Huizhen
Michael Zammit
Folks at FilChem and Castle Mountain Zeolite