evaluating the potential risk of dusts generated from
TRANSCRIPT
![Page 1: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/1.jpg)
Chongyang (Oliver) Li and Sanjai J. Parikh
Department of Land, Air and Water Resources, UC Davis
June 6 2018
Evaluating the potential risk of dusts generated from biochar-amended
agricultural soils under simulated tillage
![Page 2: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/2.jpg)
Tillage (Mechanical disturbance)Natural wind erosion
(Fugitive dust)
VS.
High potential for dust generation from agricultural fields!
![Page 3: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/3.jpg)
Biosolid
Manure
Compost
Fertilizer
Biochar
Mauri et al., 2016
• Biochars can have low bulk densities
• Biochars are often very porous and have high surface areas
Byrne and Nagle, 1997
![Page 4: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/4.jpg)
Rombolà et al., 2016
Sigmund et al., 2017
• Biochar particles may lower the cell viability
• Carcinogenic or endocrine-disrupting suspects may be
generated during the biochar production procedure
![Page 5: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/5.jpg)
Research Questions
1: More dust produced?Non amended soils Biochar amended soils
2: Dust containing more toxic compounds?
![Page 6: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/6.jpg)
Field Sampling
Laboratory Simulation
Domingo and Southard, 2006
Southard et al., 2006
Lab approach selected…..
• Minimize logistical challenges:-Weather conditions-Agronomic practices-Tillage operation
conditions
• A controlled approach is better for comparing effects from selected variables
Field Sampling vs Laboratory Simulations
![Page 7: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/7.jpg)
Soils
Biochars
Ponderosa pine wood or PW at 500, 700 and 900 ˚C
Silt Loam (SiL) Sandy Loam (SL)
Walnut shell or WS at 900 ˚C
Materials
![Page 8: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/8.jpg)
Optimized Operation Conditions:
Soil Mass: 300g;
Rotation Rate: 16 rpm;
Blower: ¼ open;
Sampling Time: 3 min;
Vacuum pump flow rate: 4L/min.
Madden et al., 2010
PM10
or
PM100
Dust collection
![Page 9: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/9.jpg)
BC marker method: BPCA
+ 65% HNO3 at 170˚C for 8 hours
Biochar content determination
Detected on liquid chromatography
![Page 10: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/10.jpg)
CALUX Bioassay
Denison et al., 2004
If any aryl hydrocarbons (dioxins, poly aromatic hydrocarbons, etc.) are present, the cell fluoresces.
![Page 11: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/11.jpg)
Evaluating impact of biochar type (constant application rate)
Airborne particle concentration Biochar content in dust
Li et al. Sci. Total Environ. 2018
![Page 12: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/12.jpg)
Walnut shell biochar (WS900) at varied application rate
Airborne particle concentration Biochar content in dust
Li et al. Sci. Total Environ. 2018
![Page 13: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/13.jpg)
Why does WS 900 biochar result in more dust emissions?
WS 900 biochar contains a considerable amount of potassium (>5% by mass)
Potassium ions disperse aggregates and form finer particles
![Page 14: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/14.jpg)
Airborne particle concentration Biochar content in dust
Permanent wilting point
Field capacity
Walnut shell biochar (WS900) at varied moisture levels
Li et al. Sci. Total Environ. 2018
![Page 15: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/15.jpg)
Bioassays to probe potential toxicity
Using different biochars Using WS 900 with different dose
Li et al. Sci. In prep.
![Page 16: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/16.jpg)
Impact of biochar type Impact of application rate (WS900)
Bioassays to probe potential toxicity
![Page 17: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/17.jpg)
Different feedstock have different chemical composition
Need further exploration
Char with more dioxin-like compounds
Char with less dioxin-like compounds
Production procedures are different:O2 contents?Metal catalyzation?
What might be there in WS 900 and what are the possible causes?
![Page 18: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/18.jpg)
• Not all biochars are problematic for dust emissions (e.g. PW biochars).
• To reduce dust, biochar can be incorporated in bands directly above the drip tape at low and high rates, and buried;
• Apply only when wind levels are low and with water added to biochar if possible;
• Appropriate personal protection equipment is required, this include respirators that are verified to fit the user;
• Test biochars in advance
• WS 900 biochar amended soils emitted more dusts than soil alone, and with higher contents of dioxin-like compounds in dusts;
Summary
![Page 19: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/19.jpg)
AcknowledgementsFunding:•Western Center for Agricultural Health and Safety Grant
•Henry A. Jastro Graduate Research Award
•USDA National Institute of Food and Agriculture (NIFA) for Hatch Formula Funding
Technical support:• Randal Southard for access to
the dust generator and Peter Narby for instructions on its usage
• Dr. Bryan Jenkins and Adina Boyce (UC Davis Biomass Laboratory) for producing and providing pine wood biochars
![Page 20: Evaluating the Potential Risk of Dusts Generated from](https://reader033.vdocument.in/reader033/viewer/2022042721/6267911dce402330cd13dd49/html5/thumbnails/20.jpg)