Progress 10/01/09 to 09/30/12
Outputs
Target Audience: Environmental scientists with interests in understanding the impacts of biochar on the availability of pollutants. Changes/Problems: We were unable to gain access to a pyrolysis unit to produce the biochar we had hoped to produce from compost and biosolids, so instead we chose to look at 2 pesticides (2,4-D and Triclosan). We also encountered difficulties associated with the relocation of the post-doc performing the 2,4-D and triclosan/biochar experiments, along with failure of the first two sequencing attempts due to instrumentation failure. Each sequencing run took 2 weeks and had a 2-3 month lead time. This resulted in a delay of 5 months in obtaining the data. Thus, by the time the sequencing was finally performed, the post-doc had relocated and I have only recently been able to find a person with the technical background necessary to process the data. We hope to finish the analysis of this data by 5/14 and submit a manuscript for publication by 7/14. A manuscript detailing the 2,4-D work requires one final revision and will be submitted for publication by 6/14. What opportunities for training and professional development has the project provided? The grant helped fund the work of a post-doc and provide opportunities for collaborative mentoring in a multidepartment setting. How have the results been disseminated to communities of interest? Via publication in the scientific literature. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
We were surprised by the lack of a toxic effect to soybeans exposed to 400mg of either zinc or copper in the Hudson soil we used since our collaborators had previously found these concentrations to have a deleterious effect on root and shoot development. One possible explanation is that the repeated wetting and drying cycles we subjected the soils to prior to either planting or biochar addition reduced toxicity compared to less actively "aged" soils. This aging process was meant to mimic seasonal processes that occur in the field and may have accounted for the lack of toxicity. The results from the 2,4-D experiments were modest and though statistically significant. Perhaps this was due to the more rapid than anticipated metabolism of 2,4-D even in the biochar treatment, which reduce the toxicity to the lettuce plants we were using as sentinels of toxicity. Below are specifics with respect to the 3 goals mentioned above. 1) One of our collaborators (Todd Walter) began investigating the effect of biochar on N and P transport shortly after this award was made so we focused instead on Heavy metals and organic pollutants, adding an additional pollutant (triclosan) 2) We demonstrated the impact of feedstock (corn vs hardwood) and pyrolysis conditions on the availability of zinc and copper, two potentially toxic heavy metals. We demonstrated that the herbicide 2,4-D was degraded more slowly in biochar amended soils, but was also less bioavailable that un-amended soil. We are in the process of analyzing the data collected regarding the effects of biochar on the impacts of the antimicrobial triclosan in soil. 3) Despite repeated efforts, we were unable to gain access to a pyrolysis unit and therefore were unable to generated biochar from either compost or biosolids so no comparative studies were possible. We did however compare two different bioenergy crop biochars as mentioned above in 2.
Publications
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: We are in the process of writing a manuscript describing the effect of biochar on the bioavailability of the herbicide 2,4-dichlorophenoxy acetic acid. It describes how we assessed the affect of 2 different biochars at different concentrations on the bioavailability of the herbicide 2,4-D using a plant germination study (with lettuce), an earthworm avoidance assay (using Eisenia fetida. Bioavailability was also measured via degradation using 14C labeled 2,4-D and measuring the release of 14C CO2. We found that biochar at concentrations above 1% in the soil enhanced germination initially, but later slightly decreased germination when the soil/biochar/2,4-D mixture was allowed to age 3 weeks. We also found that biochar decreased earthworm avoidance. Interestingly biochar decreased the degradation of 2,4-D which suggests that it was making it less bioavailable. These results may explain why plant germination was inhibited in the aged soils that had biochar additions since the biodegradation experiments suggest that more 2,4-D was still present in those soils, even though bioavailability was low. This year we performed 16S analyses on soil samples from an experiment we conducted last year, which was focused on understanding the effect of biochar addition on the microbial community in soil contaminated with the antimicrobial triclosan. Triclosan degradation has been followed by measuring the release of C14 CO2 from C14 triclosan amended soil. Colony forming units of soil microbes were counted on 1/10th R2A plates with and without triclosan to determine if any difference in antimicrobial resistance was being selected for in the presence or absence of biochar. Uncultured soil diversity is in the process of being assessed using 16S-based rRNA analyses for bacteria. DNA has been extracted from the soils and has been amplified via PCR and submitted for sequencing to the Sequencing center at Wiel Cornell Medical College in Qatar. We are currently awaiting the results. PARTICIPANTS: Individuals 1)AG Hay (PI), BK Richards, TS Steenhuis,and M. McBride (Co-PDs)participated in experimental design, data analysis, manuscript writing 2)X Chen, and J. Sanders conducted experiments, data analyses, manuscript writing. Collaborators J. Lehmann provided biochar, experimental advice and contributed to writing of the manuscript. X Chen was a visiting scientist from the Peoples Republic of China who conducted experiments, performed data analyses and contributed to manuscript writing. Sanders is a post-doc supported part time by this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The work outlined above has resulted in a change in knowledge by providing 1) more insight into the process of reduced herbicide bioavailability in soils amended with biochar, 2) a greater understanding of the variability in the effectiveness of different biochars to reduce the toxicity and bioavailability of copper.
Publications
- Zhang W., Niu J., Morales V.L. , Chen X., Hay A.G., Lehmann, J and T. S. Steenhuis. 2010. Transport and retention of biochar particles in porous media: effect of pH, ionic strength, and particle size. Ecohydrology. 3:497-408.
- Chen X., Chen G., Linggui Chen, Chen Y., Lehmann J., McBride M.B., and A. G. Hay. 2011. Adsorption of copper and zinc by biochars produced from pyrolysis of hardwood and corn straw in aqueous solution. Bioresource Technology. 102: 8877-8884.
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