Grantee Research Project Results
2002 Progress Report: Tracking Persistent Organic Pollutants (POPs) Through Biotic and Abiotic Processes in the Environment
EPA Grant Number: R828174Title: Tracking Persistent Organic Pollutants (POPs) Through Biotic and Abiotic Processes in the Environment
Investigators: Mattina, MaryJane Incorvia , Eitzer, Brian , Simon, Ted
Institution: Connecticut Agricultural Experiment Station
EPA Project Officer: Hahn, Intaek
Project Period: July 1, 2000 through June 30, 2002
Project Period Covered by this Report: July 1, 2002 through June 30, 2003
Project Amount: $194,622
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text | Recipients Lists
Research Category: Water , Air , Safer Chemicals , Land and Waste Management
Objective:
Over time, organic soil contaminants bind to soil particles and resist extraction, microbial degradation, and volatilization. This phenomenon results in the formation of weathered residues; the behavior of which is markedly different from that of freshly applied residues. This proposal will examine the cycling of weathered soil residues between the soil, air, and plant compartments by testing the following five hypotheses: (1) volatilization flux of weathered persistent organic pollutants (POPs) from soil makes a small but measurable contribution to atmospheric levels of POPs (soil-to-air translocation); (2) very low soil concentrations of POPs reflect atmospheric deposition to the site more than they reflect the direct application of an agrochemical (air-to-soil translocation); (3) POPs dose/uptake curves for soil-to-root and air-to-leaf pathways can be established (soil-to-root and air-to-leaf translocation); (4) transpiration flux of POPs from plants makes a small but measurable contribution to atmospheric concentrations (leaf-to-air translocation); and (5) municipal and commercial compost sources, as well as commercial topsoil and potting soil, contain significant amounts of POPs available for anthropogenic translocation. The cycling of weathered POPs through the biosphere must be clarified before the full impact of POPs on human health can be assessed comprehensively.
Progress Summary:
Analytical Procedures. The analytical methodologies developed in our laboratories to accomplish the grant objectives will continue to evolve during the course of these investigations. Numerous Standard Operating Procedures (SOPs) have been written, based on chiral gas chromatography (GC) with ion trap mass spectrometry (MS), and are adhered to for all determinations. Salient features of the analytical techniques developed as part of this project include the following:
- · Internal Standards. The analysis of all samples-polyurethane
foam plugs (PUFs) from air analysis, vegetation, soil, compost-is initiated
with the spiking of two internal standards (13C10 trans-chlordane and
13C10 trans-nonachlor) into the matrix at the start of extraction and
cleanup. All quantitations then are performed by the internal standard calibration
method. This method compensates for the loss of native analyte through the extraction
and clean-up steps, providing an accurate value of the native chlordane components
initially present in the sample.
· GC/IonTrap MS. For the resolution of enantiomers of trans-chlordane
(TC), cis-chlordane (CC), MC5, exo-heptachlorepoxide (HEPX), we
use a 30 m x 0.25-mm I.D., 0.25-µm Df -DEX chiral
column. The enantiomers of oxychlordane (OXY), heptachlor (HEPT), and endo-heptachlorepoxide
are not resolved on this column. We have examined a bonded chiral GC column,
the Chiralsil-DEX CB bonded column from Varian. It was hoped that the bonded
nature of this column would reduce column bleed and background noise, and increase
column lifetimes. The resolution of the OXY, TC, and CC enantiomers was exceptionally
good on this column, but unfortunately this column could not achieve baseline
resolution of -CC and +TC. Therefore, we will continue analyses on the nonbonded
-DEX chiral column from Supelco.
The chiral GC columns are rapidly fouled by consecutive injections of compost samples. To prolong chiral GC column lifetimes, a 0.5-m guard column (uncoated fused silica capillary tubing) has been inserted at the head of the chiral column. Because the chiral GC columns are nonbonded, column bleed into the ion trap tends to elevate background noise levels. To reduce background noise levels, a 0.5-m length of uncoated fused silica capillary tubing is inserted in the interface between the end of the chiral GC column and the MS source. The interface temperature can then be raised without thermally dislodging chiral phase into the source. To prolong chiral GC column lifetimes, we also have found it necessary to inject iso-octane between all injections of compost samples, a procedure that is not required for other matrices.
· Analysis for Oxychlordane. This GC/iron trap detection (ITD) analysis uses a 15-m x 0.25-mm I.D. x 0.25 Df Cyclosil B chiral column (J&W Scientific) to separate OXY enantiomers. Temperature and ramp programs have been developed, which are specific for this analysis.
· Raw Data Enhancement With PeakFit and Data Acceptance Criteria. Raw ITD data files are smoothed and integrated using PeakFit software. This permits the detection level to be considerably lowered below levels possible from the ion trap manufacturer's software. For each chlordane component, two ions within an isotope cluster are monitored and processed. The isotope ratio is assessed from two sets of authentic standards injected along with a sample set. The isotope ratios for the samples injected must be within two standard deviations of the isotope ratios from the corresponding standard sets for the sample data to be acceptable.
· Extraction and Clean-up Methods for Variety of Matrices. For soil, a homogenous soil sample is placed in the microwave-assisted extraction (MAE) vessel, spiked with internal standards, and extracted with 2:3 hexane:acetone. The extraction solution is solvent exchanged to iso-octane prior to injection into the GC/ITD.
Compost samples are thoroughly mixed. Twigs and pebbles are removed and two 10-g subsamples then are collected for extraction. After the transfer of a subsample to the blender jar, the extraction and clean-up procedures for vegetation are used as described in the following section.
For vegetation, plant tissue is rinsed thoroughly of soil, chopped, placed in a blender jar, spiked with internal standards, and extracted with 1:2 iso-propanol/petroleum ether. The petroleum ether layer is cleaned up over Florisil and solvent exchanged to iso-octane. The iso-octane extract is injected into the GC/ITD.
For air, high-volume air samplers are equipped with glass fiber filters (GFFs) to collect particulates, and PUFs to collect vapor-phase compounds. The PUFs are spiked with internal standards and soxhlet extracted with petroleum ether. The extraction solution is cleaned up over Florisil, solvent exchanged to iso-octane, and analyzed by chiral GC/ITD. The GFFs are extracted with the MAE procedure described for soils. The extract then is solvent exchanged to petroleum ether and then cleaned up on a Florisil column.
Assessment of Anthropogenic Translocation. Most previous investigations of POPs have focused on nonpoint sources as contributors to POPs cycling through the environment; for example, soil-to-air and water-to-air routes. In contrast to these previous studies, one aspect of the current project is the investigation of a point source, compost, and its anthropogenic translocation as a contributor to POPs cycling through the environment. Thirteen commercial compost samples (comm) were purchased and 39 samples of municipal composts (muni) were collected from facilities across the state. The total chlordane concentration (expressed as TC+CC+TN on a dry-weight basis) for six compositional categories of compost is shown in Figure 1. From extensive analysis of the data associated with the compost samples, we justify the conclusion that soil as a compost feedstock is not the sole contribution to the chlordane concentration in the final product; leaves, on the other hand, appear to be a major source of chlordane.
Figure 1. Distribution of Chlordane in Compost Samples. C, containing organic and manure compost; TS (comm), containing topsoil and/or sand; C + TS, containing a mixture of compost and topsoil; L, leaf and/or wood chip compost; TS (muni), primarily topsoil; L + TS, a mixture of leaf compost and topsoil-sand.
Our investigations into the cycling of POPs through the biosphere has drawn international attention. We have been contacted by a laboratory in Tunisia to collaborate with them to determine POP concentration in municipal compost samples. Accordingly, we arranged the appropriate permits through the U.S. Department of Agriculture (USDA) to receive from Tunisia four compost samples. These samples currently are being analyzed. We hope to extend this work into a long-term collaboration.
Soil-to-Air Flux. Collection of atmospheric samples for determination of chlordane concentration has been extensive throughout the grant period. From June 2000 through September 2002, ambient air samples were collected periodically at three heights (0.5 m, 1.5 m, and 2.5 m) above the experimental plot on the Connecticut Agricultural Experiment Station (CAES) campus. This plot is well documented with regard to chlordane treatment and subsequent history. In addition, air samples were collected throughout this period at a single height at a background site, approximately 25 m distant from the treated plot on the CAES campus. From May 2001 through September 2002, a suburban site, Lockwood Farm in Hamden, CT, the experimental farm belonging to CAES, was monitored. Two additional background sites were monitored from March to September 2002; the first, an urban site in downtown Waterbury, CT; and the second, a rural site at a fish hatchery in Burlington, CT. The data we have collected represent the first long-term study of the ambient air above contaminated soil. The duration of the study allows additional insight into the volatilization process previously unavailable. The data also permit the comparison with chlordane concentrations in ambient air at alternate sites. A small portion of the data is summarized in Figures 2 and 3.
Figure 2. Average Ambient Air Profiles at Each Height Above the Plot (Each Component as a Fraction of the Total) and Total Concentration from March-September 2002, Along With Average Soil Profile and Concentration
Figure 3. Average Ambient Air Profiles (Each Component as a Fraction of the Total) and Total Concentration From March-September 2002 for Each of the Four Ambient Background Sites
Soil-to-Root Uptake and Translocation Within Aerial Plant Tissues. Several food crops were grown in the field, and the chlordane component concentrations were measured in the soil contiguous to these crops, as well as in various plant tissues. The concentration of each chlordane component in the roots normalized to its value in the soil for these crops is shown in Figure 4. It is apparent that different crops accumulate chlordane components differently. Data not shown also indicate that enantiomers translocate differently through plant tissue.
Figure 4. Chlordane Component Concentration in Roots Normalized to Concentration in Soil
Soil-to-Plant Dose/Uptake. Zucchini was grown in soil containing four different concentrations of chlordane in bins, which were positioned in the field without contacting the field soil itself. The chlordane component concentrations were determined in the soil before and after planting, and in the individual zucchini tissues of roots, stems, leaves, and fruit at destructive harvest. The data permit a dose/uptake response to be estimated, as shown in Figure 5. From the nonlinear relationship between total chlordane in plant tissues and total chlordane in the bin soil as displayed in the graph, we hypothesize that plant roots uptake chlordane only within a very small region distant from the physical location of the root itself. An experiment to test this hypothesis has been completed in a growth chamber in triplicate and the data fit the hypothesis.
Figure 5. Dose/Uptake for Zucchini
We also have begun to examine another plant species, Lupinus albus, with root exudates, which may play a significant role in elucidating the soil-to-plant uptake mechanisms.
Air-to-Plant Dose/Uptake. Experiments have been completed to assess an alternate plant uptake route for zucchini. Zucchini plants were grown in clean soil in bins in two separate greenhouses containing significantly different chlordane ambient air concentrations. The experimental setup is shown in Figure 6. One of the most surprising results of these trials is the confirmation of translocation of the chlordane taken up through the leaves through the phloem throughout plant tissues, including accumulation in the roots.
Figure 6. Greenhouse Trial for Investigation of Chlordane in Air/Uptake by Zucchini
Comparison of the Air-to-Plant Uptake with the Soil-to-Plant Uptake Routes. Our data demonstrate for the first time that Cucurbita pepo L. uptakes and translocates chlordane residues through two distinct uptake routes. The two uptake pathways can be distinguished from each other through several different manipulations of the data. One such data presentation is shown in Figures 7 and 8. Both the compositional profile and the enantiomeric profile of the chlordane residues, which translocate from the source compartment (soil or air) through the plant tissues, differ markedly for the two routes, as the color coding in Figures 7 and 8 depict.
Figure 7. Changes in Chlordane Residue Profiles for the Air-to-Plant Uptake Route
Figure 8. Changes in Chlordane Residue Profiles for the Soil-to-Plant Uptake Route
Broader Implications of the Data from the Soil-to-Plant and Air-to-Plant Dose Uptake Routes. The POPs uptake capability of C. pepo L. is exceptional. As a result of our studies completed through the funding from this grant, we have begun to investigate the uptake mechanisms that produce these observations. Our laboratory has received a grant for these phytoremediation studies. In addition, several additional grants to extend the phytoremediation investigations begun under U.S. Environmental Protection Agency (EPA) Star Grant No. R828174 are pending.
Future Activities:
We will continue the design and implementation of growth chamber experiments and the assessment of data from air and vegetation for its impact on human health.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
| Other project views: | All 17 publications | 7 publications in selected types | All 7 journal articles |
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Eitzer BD, Mattina MI, Iannucci-Berger W. Compositional and chiral profiles of weathered chlordane residues in soil. Environmental Toxicology and Chemistry 2001;20(10):2198-2204. |
R828174 (2000) R828174 (2002) R828174 (Final) |
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Lee WY, Iannucci-Berger W, Eitzer BD, White JC, Mattina MI. Persistent organic pollutants in the environment: chlordane residues in compost. Journal of Environmental Quality 2003;32(1):224-231. |
R828174 (2002) R828174 (Final) |
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Lee WY, Iannucci-Berger W, Eitzer BD, White JC, Mattina WI. Plant uptake and translocation of air-borne chlordane and comparison with the soil-to-plant route. Chemosphere 2003;53(2):111-121. |
R828174 (2002) R828174 (Final) R829405 (Final) |
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Mattina MI, White J, Eitzer B, Iannucci-Berger W. Cycling of weathered chlordane residues in the environment: compositional and chiral profiles in contiguous soil, vegetation, and air compartments. Environmental Toxicology and Chemistry 2002;21(2):281-288. |
R828174 (2000) R828174 (2002) R828174 (Final) |
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White JC, Mattina MJI, Eitzer BD, Iannucci-Berger W. Tracking chlordane compositional and chiral profiles in soil and vegetation. Chemosphere 2002;47(6):639-646. |
R828174 (2002) R828174 (Final) |
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Supplemental Keywords:
atmosphere, soil, chemical transport, health effects, dose-response, measurement methods, environmental chemistry., RFA, Health, Air, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Waste, Water, Toxics, Susceptibility/Sensitive Population/Genetic Susceptibility, Fate & Transport, pesticides, chemical mixtures, genetic susceptability, Environmental Chemistry, Engineering, Chemistry, & Physics, Contaminated Sediments, tropospheric ozone, Bioavailability, air toxics, Environmental Monitoring, biotic processes, Chlordane (technical mixture and metabolites), contaminant transport, dietary exposure, environmental hazard exposures, sensitive populations, health effects, mass spectrometry, microbial degradation, soil contaminants, weathering, stratospheric ozone, contaminated sediment, human exposure, climate variations, organic soil contaminants, pollutants, atmospheric deposition, insecticides, abiotic processes, chemical contaminants, degradation of organic pollutants, agricultural community, pesticide residues, persistent organic pollutants, exposure, fate and transport, Chlordane, biodegradation, pesticide runoff, sediment transport, chemical transport, agriculture, agrichemicals, persistant organic pollutants, DDT, atmospheric processes, exposure and effectsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.