SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
IN-PLACE INACTIVATION AND NATURAL ECOLOGICAL
RESTORATION TECHNOLOGIES SOIL-METALS ACTION TEAM MEETING
JOPLIN SITE COMMITTEE
Kansas City, Missouri
October 7, 1998
WELCOME
Dr. Bill Berti, DuPont Central Research and Development
Dr. James Ryan, U.S. Environmental Protection Agency (EPA)
Dr. Bill Berti and Dr. James Ryan, the meeting co-chairs, welcomed participants (see Attachment A) and reviewed the agenda for the In-Place Inactivation and Natural Ecological Restoration Technologies (IINERT) Soil-Metals Action Team(1) meeting. The Joplin Site Committee was gathered, Dr. Berti explained, to review ongoing research efforts at the Joplin, Missouri, site and share collected data among participating agencies. (The Joplin site is a residential area, approximately one-half acre in size, that was contaminated as a result of lead smelting and mining. The site is contaminated with lead at concentrations ranging from 400 to 5,000 parts per million [ppm]). Dr. Berti said the meeting participants would:
· Examine and compare the results of in vivo swine and rat studies.
· Examine the results of the in vitro studies.
· Compare the in vivo and in vitro results.
· Decide upon additional studies and sampling needed for the Joplin site.
SUMMARY OF KANSAS STATE UNIVERSITY ACTIVITIES
Dr. Gary Pierzynski, Kansas State University
In Vitro Study Results
Dr. Gary Pierzynski presented selected chemical properties of soil materials from five sites that he is working on (Time Critical Repository, Active Repository, Joplin plots, Chat plot, and Dearing plot) that have elevated lead concentrations.
Dr. Pierzynski outlined the protocol used in the preliminary stabilization study: it consisted of preacidifing the soil samples to pH 5 before adding phosphate solution, allowing the samples to sit for 24 hours before adding the phosphates, and then neutralizing the samples with calcium oxide 24 hours after that. He said his team tried to assess bioavailability using the 0.4 M glycine method, but found the tests to be insensitive to treatment effects at pH 1.5, 2.0, and 2.5. Dr. Pierzynski noted that data generated by the sequential extraction procedure demonstrated some treatment effects as did the use of the intestinal phase of the old PBET procedure. Dr. Pierzynski said that since the combination of the "old intestinal phase" method and the new glycine method remains untested, he directed his research group to switch to the Ruby et al. (1996) PBET procedure.
Dr. Pierzynski noted that one of his graduate students has begun another incubation study using acetic acid preacidification, which is a one-step procedure. This procedure, he continued, has been useful for all the sites except the Dearing site, which required treatment with phosphoric acid due to the more acidic conditions present there. Phosphoric rock was not found to be very effective at the Dearing site, but after 4 weeks of incubation, phosphoric acid treatment was found to be the most effective treatment. A participant commented that the “percent of lead bioavailable” after the incubation period is not related to in vivo bioavailability and the term used should, therefore, be “soluble” rather than “bioavailable.”
Dr. Pierzynski said that treatment effects varied depending on the sample. The phosphoric acid treatment is most effective in samples that have a high pH and chat content. Dr. Pierzynski's group has conducted the studies over 3 days and 4 weeks, and the procedure will continue to be monitored over time. Dr. Pierzynski discussed the use of sodium bicarbonate with the dialysis tubing to adjust pH in the intestinal phase of the test, saying it was a useful method because it does not require a lot of monitoring; this allows multiple samples to be run. Mr. Mike Ruby stated that the addition of sodium carbonate directly to the solution creates micro-environments of high pH and the lead precipitates out of the solution.
Dr. Pierzynski stated that using the in vitro test with the glycine buffer, his group had found no difference in relative bioavailability between samples that had been incubated for one month and those that had been incubated for one year. He also indicated that lead was observed to precipitate out in the intestinal phase rather than the stomach phase in the controls, causing him to wonder if bile salts, which also contain phosphorus, were affecting the results. Dr. Sally Brown asked Dr. Pierzynski if water-soluble extractions had been conducted and Dr. Pierzynski replied that they had not yet been undertaken. Dr. Pierzynski stated that the rate and source effects were clearly different for different types of samples.
Dr. Pierzynski said that the Dearing sample showed high Olsen phosphate values initially and the addition of phosphate rock did not increase phosphate levels, while the addition of other forms of phosphate caused phosphate levels to increase. Dr. Pierzynski indicated that his research group was monitoring mineralogy in the Dearing soil samples that had been aged for 4 weeks. He felt that by monitoring phosphate levels in the soil samples, he could be more confident that the phosphate pyromorphite was being converted into lead phosphate. Dr. Pierzynski described the particle size procedure (dry) used to concentrate lead phosphate, which involved sieving the soil samples with a traditional 50 micron sieve, followed by sedimentation to less than 2 microns in size. The other method of separation is the ultrasonic method, which involves dry sieving of the soil samples with a 40 micron sieve and then the separation of particles smaller than 10 microns by ultrasonic techniques. It is hoped that the ultrasonic method will indicate the true treatment effects. The control samples indicate that little pyromorphite is present before treatment. Pre-acidification with acetic acid has not been found to be a very effective treatment. Triple super phosphate solution at 5,000 ppm was found to be more effective than triple super phosphate solution at 2,500 ppm. Dr. Pierzynski indicated that an inert reference material should be used as an internal standard for possible semi-quantification of pyromorphite by X-ray diffraction (XRD).
Dr. Pierzynski indicated that treatment of the soil samples with phosphate rock causes some increase in the pyromorphite peak as well as some apatite peaks, but that phosphate rock is not as effective as phosphoric acid. He indicated that his group is attempting to do some further concentration of the samples.
PBET (Ruby et al, 1996) Method
Dr. Pierzynski asked for comments on how to determine the effectiveness of the PBET method. Dr. Ryan replied that it was necessary to monitor pH and solubility as related to animal feeding. Dr. Ryan stated that the pH should be monitored on a routine basis, and that this was much simpler if organic matter was not added to the soil. Another participant stated that the PBET method can be used without the buffering agent and can be based entirely on pH. This participant stated that the Environmental Protection Agency (EPA) conducted the glycine test in closed bottles and that the results correlated well with the EPA Region 8 swine studies. The participant thought that the glycine method correlated well with the traditional method at pH 1.5 and 2.5.
Dr. Pierzynski indicated that using the extraction method, more of a treatment effect is observed in the intestine phase of the test in comparison with the stomach phase using glycine. Dr. Pierzynski also observed effects at both high and low pH in the stomach and the intestine with the extraction method. Dr. Brown indicated that similar effects had been observed at the Joplin site, where Dr. John Drexler had conducted the glycine test at pH 1.5, but treatment effects had not been observed in the U.S. Department of Agriculture (USDA) plots on the site. Dr. John Yang reported that the bench study for 1% phosphate solution showed a reduction of bioavailable lead of 60 to 68%, which correlated with the swine data. Another participant stated that the treatment effect of the glycine method is unknown, due to the observed inconsistencies.
Questions/Comments for Dr. Pierzynski
Dr. Ryan commented that he felt the TSP500 solution, which is an 8.5 M solution of phosphate, is quite a high concentration of phosphate from a thermodynamic perspective.
Dr. Rufus Chaney asked if the control for the Dearing soil had a low Olsen phosphate content. Dr. Pierzynski replied that it had an Olsen phosphate concentration of 16 ppm.
Dr. Berti asked if the treatment affects particle size. He also asked if there were any differences in the amount of lead being collected in the less than 10 micron fraction than in the other fractions. Dr. Yang replied that, based on his experience, total lead increased from sand to clay. Dr. Pierzynski indicated that while he has not yet examined treatment affects on particle size, it is something that he will study. Dr. Berti asked if any other treatment studies had been conducted. Dr. Pierzynski replied that his group will conduct some further incubation studies and that a medical school student will be conducting some in vivo feeding studies; the results from the plant studies conducted by Dr. Brown will be compared with the results from the incubation studies.
Dr. Berti indicated that in the Joplin plots that the 3.2% phosphorus USDA treatment showed a greater than 76% reduction in lead uptake into plant shoots compared to the untreated plots. He indicated that the best treatment (1% phosphate, surface aeration Missouri treatment) showed an average reduction of bioavailable lead (as measured with the in vitro test, pH 1.5, 0.4M glycine) of 40%. Dr. Yang conducted several analyses on these soil plots to determine how homogenous the soil within each plot is, with regard to pH, after surface injection of the treatments. Dr. Berti stated that this data had been sent to the Joplin Site subcommittee members. Dr. Pierzynski pointed out that all the low total lead concentrations are found in the plots treated with 1% phosphorous and aeration, while all the high lead levels are found in the control plots. Dr. Pierzynski wondered if the reduction in total bioavailability is not related to total lead and asked how these effects could be separated. Dr. Brown suggested that the data be analyzed to show the difference between extractable and total lead. Dr. Berti suggested that someone be appointed to conduct such an analysis and Mr. Dave Mosby agreed to take on the task.
The plots at Joplin consist of a randomized block design and Dr. Berti asked if there was a spatial description of the plots.
Dr. Berti asked Dr. Yang what percentage of reduction of bioavailable lead was found in the swine studies. Dr. Yang replied that the soils containing 1% phosphate that had been rototilled showed 30 % bioavailability compared to 19% in the control sample. Mr. Mosby indicated that the 30 % reduction had taken place in a field sample and that a 36% reduction had been observed in the laboratory, compared to a 1% reduction in the control sample.
METHODOLOGICAL DISCUSSIONS
Percent Bioavailability Calculations
Dr. Berti indicated that the group should discuss how to calculate percent reduction, so that they are all consistent in their calculations. Dr. Berti suggested that changes in bioavailability be calculated by the following formulas:
Percent change from the control=[control - treatment /(control)] * 100%
or
Reduction due to treatment=[treatment/control] * 100%
Dr. Yang said he thought Dr. Stan Casteel used the first formula to calculate changes in bioavailability in his most recent report. Dr. Chaney suggested that Dr. Casteel’s calculation assumptions should be clarified, so that the data generated by Dr. Casteel’s feeding study can be compared with Dr. Yang’s data.
Validation Study of In Vitro Method
Mr. Mark Doolan reported that the EPA validation study of an in vitro method, which is hoped to be a less costly alternative to in vivo swine studies, was in progress and that Dr. Chris Weis had found that the method was well reproduced on test samples sent to three different labs. Dr. Weis is now in the process of selecting soils (that were used in the swine studies) for analysis. Mr. Doolan said EPA estimates that the method validation will be complete by March 1999. Mr. Ruby stated that an initial set of 20 samples has been sent to the participating labs. An additional group of samples is currently being selected (including the Joplin site, Oklahoma samples taken by Dr. Nick Basta, and samples used for early industry rat feeding studies). Mr. Doolan indicated that he would like to see the completion of the validation study so that he could use the in vitro method. Mr. Ruby cautioned that there was still a fair amount of contradiction between the in vivo and in vitro methods and that it had not yet been demonstrated that the in vitro method could be used for amended soils.
COMPILATION OF DATA COLLECTED AT THE JOPLIN SITE
Dr. Brown suggested compiling the Joplin data collected by the various participating agencies, so that it would be easier to compare the data. Dr. Brown indicated that plant lead data shows some seasonal variability: lead levels in plants tend to be higher in the fall than in the spring. One participant commented that the data are all comparable except in the PBET extraction procedure used. Dr. Chaney commented on the value for the field control in the PBET study, asking if this value would not be equivalent to almost all the lead in the soil. Dr. Ryan replied that this high lead concentration is the result of the use of pH 2 solution in the extraction procedure.
The group discussed the treatment effectiveness of the swine studies conducted by Dr. Casteel, noting that the study did not use a lead acetate control in the study and instead relied on older lead acetate data. Dr. Yang thought that Dr. Casteel had run a lead acetate control in his latest study, but that he had not provided Dr. Yang with the data. Dr. Berti thought that the field control value was 0.68 or 0.69 as a Relative Bioavailability (RBA) value, relative to lead acetate.
Dr. Yang stated that the soil samples used in the swine feeding studies are composites from four plots which are mixed and sieved prior to being fed to the swine. Dr. Yang said that he also had soil data for the individual plots from which the composite samples were compiled. In response to a question from a workshop participant, Dr. Yang said the soil samples were extracted with a 2-inch probe to a depth of 15 centimeters (cm). Dr. Brown indicated that these probes are difficult to get into the plots.
Dr. Ryan asked if the soil being fed to the swine was composed of particles less than 200 microns in size. Dr. Yang replied that he used a 60 mesh sieve which filters out particles larger than 250 microns. Dr. Ryan then asked if Dr. Yang had conducted analyses on the bulk samples and compared them to the analyses conducted on the fraction of soil that is smaller than 250 microns.
Mr. Ruby stated that he thought the percentage reductions were so large in the Yang method due to the fact that the pH of the soil solution starts out at 2 and increases to 2.5 during the course of the treatment. The pH of the other solutions starts at 1.5 and the addition of hydrochloric acid keeps the pH at this level throughout the treatment reaction. Dr. Brown disagreed with Mr. Ruby’s opinion that the large percentage reductions in the Yang method were entirely attributable to a pH difference. She said that she had done some studies with compost at a similar pH and she felt the pH did not change much during the course of the experiment. Mr. Ruby felt that the Yang data was anomalous compared to the rest of the data presented because of the large percentage reductions in bioaccessibility and indicated that he was trying to think of causes for the large reduction observed. Mr. Ruby suggested that a critical precipitation reaction may be occurring between pH 1.5 and 2.5. Dr. Chaney indicated that in controlled soils, precipitation may be occurring with the 1% phosphate solution over the duration of the extraction (1 hour). Mr. Ruby indicated that he would prefer to see the extraction conducted at pH 1.5, with the pH maintained at this level throughout the treatment.
Another participant stated that no treatment effects, as determined by changes in bioavailability measured with pigs and rats, had been observed with the use of the PBET at pH 1.5 with glycine. This test also was underpredictive for plant availability. Dr. Chaney indicated that PBET using glycine at pH 1.5 has not yet been shown to be more conservative than animal feeding studies.
Dr. Brown provided data from a recent swine feeding study that showed that field soil treated with phosphate and iron and incubated for 1 year had a higher RBA than the untreated control. Mr. Mosby suggested that more robust data are needed. He said feeding studies were done with composite soils, while the chemical characteristics for the soils were determined only for individual plots, not the composite samples. Dr. Pierzynski asked if data confirmed that phosphate was still in the soil plots. Dr. Brown indicated that Dr. Berti has these data and that they had also placed barriers around the plot to prevent leaching of the phosphate. Dr. Brown indicated that it was possible that iron causes the precipitation of phosphate.
Dr. Berti pointed out that the use of different analytical methods for phosphate brought quite different numbers (i.e., 300 to 600 ppm in a field control measured by a colorimetric method and 1,000 to 6,800 ppm by ICP). A participant asked if such significant differences could have arisen from mislabeling of a plot and suggested that aluminum signs be used to label the plots. Dr. Chaney suggested that phosphate be analyzed on a more regular basis prior to compositing the samples. Dr. Yang indicated that the composites are composed equally from four plots and that he has total lead data for the soil in the individual plots. Dr. Yang suggested that there is a lot of spatial variability of pH, phosphate, and lead in each plot. Mr. Mosby indicated that he had observed considerable variability in total lead laterally within a plot. Dr. Yang’s study indicates that mixing of the treatment into the soil is well accomplished in the horizontal direction, but not vertically. Dr. Yang added that column leaching experiments show that 25% of the phosphate migrates to 70 cm below the soil surface. Mr. Doolan asked Dr. Yang where the greatest variability in pH occurred; Dr. Yang replied that the first breakpoint occurs at 5 cm and the second at 10 to 15 cm.
Mr. Ruby said in vivo tests are too expensive to use routinely and that an adequate in vitro test needs to be developed. He then asked the group how closely such an in vitro test would need to approximate the results of an in vivo test. Dr. Brown indicated that the rat and swine studies have shown good agreement, while Mr. Mosby pointed out that the rat study does not show as great a reduction in RBA as the swine study. Mr. Mosby stated he was unsure about the field control value that was used to calculate the RBA. Several scientists stated that they had tried to “back calculate” the field control value from the RBA.
Mr. Ruby asked what bioavailability reduction would be considered successful to consider using this technology for residential soils. Mr. Doolan felt that if a treatment could cause a 30% reduction in lead bioavailability it could be considered successful because this RBA would move the threshold of concern (trigger level for action) from 500 ppm to 650 ppm. Mr. Doolan indicated that EPA is currently treating private yards within the Joplin site that are contaminated with more than 1,000 ppm lead. (The 1,000 ppm value was derived using the IEUBK model, with a trigger level of 800 ppm and 19% reduction in bioavailability.) Mr. Doolan felt that it was best to avoid digging up yards that had lead contamination at levels between 500 and 700 ppm. Treatment and revegetation, he said, are a much more cost-effective option and thereby allows a larger number of properties to be treated, rather than only those properties that are contaminated with 800 to 1,000 ppm lead. Other health agencies might disagree: the Agency for Toxic Substances and Disease Registry and the state health department would like to see a threshold for treatment set at 440 ppm. Dr. Pierzynski stated that although one may consider the health effects from exposure to 500 ppm and 1,000 ppm lead the same, these effects may still pose an unacceptable risk to human health. Mr. Doolan felt that unacceptable health risks would not occur as long as the soil contained less than 1,000 ppm lead and was vegetated.
The group further discussed the compatibility of the data compiled so far. Dr. Berti felt that it was necessary for someone to analyze the data, document the experimental methods used and determine how comparable the data are. The group decided that Mr. Mosby should do this task because it is related to his Master’s thesis. Dr. Brown questioned whether data collected from the same plots at different times can be considered the same for the Committee’s purposes. She indicated that the swine and rat data are normalized and that in vitro studies can be normalized for total lead. She said that there are several areas where rat and swine data (1% phosphate) were collected from the same plots and that Mr. Mosby could use these for his analysis. Another participant added that there is other information that cannot be used because it does not fall within the data set (i.e., different treatment procedures were used). Mr. Ruby said he could assist Mr. Mosby by providing him with background information about how the different studies were run. Dr. Berti stated that another outstanding question was the interpretation of the swine field data because of the lack of lead acetate controls.
The group focused their discussions on how best to compare the rat and swine data. One participant felt that it was necessary to compare bone data when looking at different species. Another participant reviewed the method used by Dr. Casteel for the other participants. The participants decided that the following formula best represented the average RBA to be compared among species:
Average RBA=[(Blood RBA) + (kidney+bone+liver)/3]/2
Mr. Ruby stated that he thought that data should be compared in a way that would yield the smallest error bars. He indicated that bone measurements in swine are “noisy” (i.e., there can be a large variability in the measurements) but that rat bone measurements are quite reproducible. Dr. Chaney stated that he would like Dr. Casteel to indicate how comparable the animal species are. (Dr. Casteel was unable to attend the meeting).
Mr. Doolan indicated that he was interested in the plant data for the Joplin site. Dr. Brown stated that she had not yet plotted the data collected in September 1997 with that collected in May 1998 to determine if there is any interaction between the two data sets. Mr. Mosby indicated that while there seems to be very little correlation between cadmium and zinc levels in the untreated and treated plots at the Joplin site, a correlation does seem to exist for the lead data. Dr. Brown indicated that the addition of triple super phosphate did not reduce the lead levels in the plants.
ELEVATED BLOOD LEAD LEVELS DUE TO LEAD PAINT AT THE JOPLIN SITE
Mr. Doolan indicated that about 13% of the children within the Joplin community have blood levels that exceed 10 µg/dl. He stated that a study had taken place to determine whether paint in the homes at Joplin was contributing to the increased blood lead levels. A study of 171 children found that a correlation could only be found between the elevated blood lead levels and soil lead levels; there was no correlation with lead levels in paint or water. Dr. Chaney cited the case of a study that had used the wrong type of x-ray to measure lead paint in homes. Mr. Ruby commented that paint may be the source of the contamination if a correlation can not be demonstrated between the elevated blood lead levels and household dust. Mr. Doolan stated that he had tried to do a correlation study between soil and indoor dust, but that no correlation would be found unless the lead content in the house dust were higher than that in the soil.
Mr. Doolan cited a study conducted by a consultant that indicated that blood lead levels increased by 22% within 0.5 miles of the smelter at Joplin. The study sampled equal numbers of children in the area near the smelter whose yards had been cleaned up, children in the area of the smelter whose yards had not been cleaned up, and children in other areas of the county. The children who resided near the smelter and had their yards cleaned up showed a 10 % exceedance of normal blood lead levels, while those children residing around the smelter whose yards had not been cleaned up showed a 12% exceedance of normal blood lead levels. The children in other parts of the county showed a 14% exceedance of normal blood levels. Mr. Doolan explained these discrepancies in part by stating that the Joplin school district has a very strong lead poisoning awareness and education program. Such programs are not in effect in other areas of the county. Dr. Chaney stated that it is important to distinguish between the reduction in blood lead levels caused by cleanup of the area and those caused by awareness or education. The fact that children can still have high blood lead levels even after their yards are cleaned up is another reason why Mr. Doolan believes lead paint contributes to elevated blood lead levels.
PHOSPHATE AND METALS LEACHING AT THE JOPLIN SITE
Mr. Dave Mosby, Missouri Department of Natural Resources
Mr. Mosby stated that 50 acres of the Joplin site were reclaimed as a demonstration project. He stated that different sources of organic matter such as poultry/hog manure composted with recycled newspaper, raw turkey litter, composted municipal sewage sludge or biosolids, wastewater treatment sludge from the city of Springfield, and spent mushroom compost (a composite of hog and cow waste that is used to grow mushrooms) were used. Mr. Mosby described the study design and indicated that phosphorus from diammonium phosphate treated plots leached into the shallow ground water to a much greater extent than the phosphoric acid treated plots. Mr. Mosby said the phosphate from phosphoric acid treated plots did not leach very deeply in comparison to the diammonium phosphate treatment. Two days after phosphoric acid treatment, Mr. Mosby added hydrated lime to the treatment plots and then sampled for metals. The results of the metals analysis showed very high levels of dissolved metals. Mr. Mosby stated that the metals and phosphoric acid are well bound in the top six inches of the soil. Mr. Mosby stated that contrary to what was expected, the mine waste was not dominated by CaCO3, but was mostly silica. That is why there was a problem with the leaching of metals in both phosphate treated plots. Dr. Berti suggested that the use of rock phosphate may not create migration problems.
Dr. Ryan added that he was curious about the fact that phosphate migration was observed with the diammonium phosphate treatment but not to the same extent in the triple super phosphate treatment. Dr. Brown stated that the phosphate is still there, but that it may be present in a different form. Dr. Yang proposed an experiment using XRD analysis to determine how available the phosphorus is in the soil. The group also discussed the conversion of lead to pyromorphite and how best to determine if this conversion is taking place. The group decided that XRD analysis would not be sensitive enough and proposed Scanning Electron Microscope (SEM) analysis or XRD in combination with techniques that concentrate heavy metals.
Dr. Pierzynski suggested that metals are solubilized by a decrease in pH. Mr. Doolan stated that Mr. Mosby’s findings, coupled with the difficulty in finding a contractor that would work with large quantities of phosphoric acid, caused the cancellation of the massive phosphate treatment planned for the Joplin site. Dr. Brown suggested that they look at other treatments, such as biosolids, because phosphate treatment will not restore the vegetative cover needed for ecosystem health. Dr. Chaney stated that acid treatment will destroy legumes that are vital in the nitrification process. Dr. Brown advocated the use of biosolids over compost because compost is more of a low-grade fertilizer and a soil conditioner. Biosolids are more chemically reactive and potentially more cost effective than a soil conditioner. She indicated that when using a compost, one must often add essential nutrients such as nitrogen, potassium and phosphorus. Dr. Brown stated that biosolids can be transformed into soil by time and soil process and that this may be a more cost-effective solution, even though one will not see growth immediately.
THE USE OF BIOSOLIDS TO RESTORE VEGETATION AT BUNKER HILL, WASHINGTON
Dr. Sally Brown, University of Washington
Dr. Brown presented slides of vegetative growth at Bunker Hill, a former smelter site, and provided information about the restoration which was conducted at the site. The Bunker Hill site has acidic surface soil (pH 1 to 4) which contains high levels of zinc (2,000 ppm). Dr. Brown said that biosolids mixed with wood ash were applied to the soil surface by truck. One year after application, Dr. Brown continued, the area is covered in lush growth, which has significantly reduced erosion in the area. Dr. Brown noted that the initial transient ammonia toxicity problems caused by the use of biosolids and wood ash (which has a high pH) were overcome, but she recommended using fly ash in subsequent projects because of its neutral pH. She also recommended a delayed seeding or the use of fly ash with a higher calcium carbonate content as opposed to calcium oxide. Dr. Brown said that replicated field plots were set up in a tailings area that contained 5,000 to 12,500 ppm zinc, and the areas treated with biosolids demonstrated lush growth. Dr. Brown stated biosolids are not washed away from the test plots because they form an adhesive mixture when mixed with wood ash. Dr. Brown said that there was also a series of small replicated test plots that were treated with composts and high-nitrogen containing biosolids; these yielded greater vegetation than those treated with more conventional methods such as organic fertilizers. Success at the site was measured primarily by vegetation growth and to a lesser extent by metals uptake and water quality. Dr. Brown said it is important to demonstrate persistence of growth.
Dr. Ryan asked if there were high lead and cadmium levels at the Bunker Hill site. Dr. Chaney replied that both zinc and lead smelters had been located on the site and that lead and zinc concentrations varied by location within the site. Dr. Chaney asked if small mammal studies will be conducted at the site. Dr. Brown replied that Harry Compton would contribute some resources to monitor this at the newly installed wetlands site project and that she would like to see the IINERT group act as host or clearinghouse for some of these types of related work. Dr. Yang asked what types of plant species were used at the site and Dr. Brown replied that there had been a lot of volunteer species in addition to the native seed mix used.
DATA SHARING
The workgroup felt that it was important to share information gathered at the Joplin site early in the process and once again after it had been published. The group discussed various ways to disseminate the available data among the active members of the IINERT group without making the information too public before it has been published. A participant suggested that each agency should publish its data and then all the data should be combined to form a final report. Dr. Chaney stated that if the individual data are not “cleaned up” properly, it will be impossible to combine them into one summary report. Another participant stated that better coordination is necessary to ensure that the final product is useful.
Dr. Brown suggested that a schedule be developed for analysis and publication of the data. Another participant added that the Joplin site will require validation in 2 or 3 years to ensure that the treatments worked and that resources will have to be found for this exercise. The group decided that Mr. Mosby will write a paper that compares the mammal, plant, and in vitro data for a peer-reviewed journal, preferably Environmental Science and Technology. Dr. Brown will use a subset of the data to write an article that compares the plant and in vitro data. Mr. Doolan suggested that Mr. Mosby also put together all the available data in spreadsheet form and provide it to the other active committee members. The group also felt that it was important to develop a standard format so that all the group members can access the information by E-mail, since not everyone can use the current format. The group discussed whether it would be necessary to record sampling protocols and analyses. Mr. Ruby also suggested that both the glycine and traditional in vitro tests be conducted on the next set of samples in order to provide a comparison of the methods.
COORDINATING SAMPLE COLLECTION
Dr. Brown suggested that the next sampling effort at Joplin be coordinated and structured, so that two sets of samples can be taken that can be split for a similar analysis schedule. She suggested that Dr. Drexler perform the PBET analysis so that the group will have more data points that are comparable, since Dr. Drexler conducted the last set of PBET analyses. Mr. Mosby indicated that the SEM in his lab has been out of order for a while and may remain that way for some time. Mr. Mosby indicated that they are still awaiting some analyses from their third sampling round.
Dr. Berti indicated that one of the Joplin treatments was not collected last May. The group suggested having Dr. Drexler perform in vitro analyses on the samples and recommended having Dr. Brown conduct the plant analyses. Mr. Ruby asked whether the group had sufficient funding to undertake the construction of a synthetic, lead-free soil to which lead can be added as needed, so that both types of soil can be used in the feeding studies. Mr. Mosby replied that he had already tried to do this but had been unsuccessful.
Dr. Berti asked if speciation methods or SEM analyses have been used to design better treatments. Another participant stated that a lot of samples had been collected, but that a limited amount of lab analysis had been conducted on the samples because the validity of the analyses still need to be confirmed. Dr. Ryan asked if there were sufficient amounts of field samples left over to be used for examining treatment effects. The group decided that there were probably sufficient amounts of samples left over in most cases to conduct experiments examining treatment effects. Dr. Ryan suggested that the scientists who would be taking samples at the Joplin site on October 8, 1998, should double the amount of soil that they normally take, in order to conduct some treatment effect studies. The group decided to take 2 kilograms of soil from each plot to be used in animal dosing studies. Mr. Ruby asked Dr. Yang about the “chain of custody” procedure used to handle the Joplin samples because he had received a request from Dr. Weis in EPA Region 8 for some of the Joplin samples for his own validation studies. Dr. Yang replied that all the Joplin samples are kept locked up and that he thought the samples would meet the “chain of custody” requirements. Another participant suggested that Dr. Weis should use samples remaining from Dr. Casteel’s in vivo feeding studies.
The workgroup participants made arrangements to meet at the Joplin site. Dr. Berti thanked everyone for attending and adjourned the meeting.
Attachment A
Final Attendee List
RTDF IINERT Soil-Metals
Action Team Meeting,
Joplin Site Committee
Park Place Hotel
Kansas City, MO
October 7, 1998
DuPont Central Research and Development
Glasgow Site 301
P.O. Box 6101
Newark, DE 19714-6101
302-451-9224
Fax: 302-451-9138
E-mail: bill.berti@usa.dupont.com
University of Washington
234 Bloedel Hall
College of Forest Resources
Box 352100
Seattle, WA 98195
206/616-1299
206/685-3091
slb@u.washington.edu
Research Agronomist
Environmental
Chemistry Laboratory
U.S. Department of Agriculture
BARC West - Building 007
Room 212
Beltsville, MD 20705
301-504-8324
Fax: 301-504-5048
E-mail: rchaney@asrr.arsusda.gov
Remedial Project Manager
Superfund Division
U.S. Environmental Protection Agency
726 Minnesota Avenue
Kansas City, KS 66101
913-551-7169
Fax: 913-551-7063
E-mail: doolan.mark@epamail.epa.gov
Environmental Specialist
Hazardous Waste Program
Missouri Department of Natural Resources
P.O. Box 176
Jefferson City, MO 65102
573-751-3176
Fax: 573-751-7869
E-mail: nmosbd@mail.dnr.state.mo.us
Associate Professor
Department of Agronomy
Kansas State University
2004 Throckmorton
Plant Sciences Center
Manhattan, KS 66506-5501
913-532-7209
Fax: 913-532-6094
E-mail: gmp@ksu.edu
Exponent Environmental Group
4940 Pearl East Circle
Boulder, CO 80301
303-444-7270
Fax: 303-444-7528
E-mail: rubym@pti-enviro.com
Soil Scientist
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
5995 Center Hill Avenue
Cincinnati, OH 45224
513-569-7653
Fax: 513-569-7879
E-mail: ryan.jim@epamail.epa.gov
Research Biologist
Human Nutrition Research Center
U.S. Department of Agriculture
BARC East - Building 307
Beltsville, MD 20705
301-504-8988
Fax: 301-504-9098
E-mail: xue@bhnrc.arsusda.gov
Soil Chemist
College of Arts and Sciences
University of Missouri - Columbia
101 Geology Building
Columbia, MO 65211
573-882-7341
Fax: 573-882-5458
E-mail: geoscjy@showme.missouri.edu
RTDF logistical and technical support provided by:
Environmental Chemist
Eastern Research Group, Inc.
Apt. 401
40 Park Road
Toronto, Ontario M4W2N4
416-413-9229
Conference Manager
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3134
781-674-7347
Fax: 781-674-2906
E-mail: sbmurphy@erg.com
Conference Coordinator
Eastern Research Group, Inc.
110 Hartwell Avenue
Lexington, MA 02421-3134
781-674-7320
Fax: 781-674-2906
E-mail: lstamata@erg.com
(1)1 The IINERT Soil-Metals Action Team was established in November 1995 as one
of seven action teams under EPA’s Remediation Technologies Development
Forum (RTDF). The team includes representatives from industry and government
who share an interest in developing and validating in situ techniques as
viable technologies for eliminating the hazards of metals in soils and other
surface materials.