Brief Summary of Minutes of Annual Meeting

Objective 1: Evaluate the risk-based effects of residual application to uncontaminated (e.g. baseline) soils on chemistry, bioavailability, and toxicity of nutrients and contaminants. Many of the participants actively performed research relevant to this objective. In Michigan, a seven-year field study evaluated amendments of alum water treatment residuals (WTR) to soils having high to very high soil test P levels. Bray P1soil test levels in surface soils have declined with time at all sites, and alum WTR contributed to this decrease at most sites. Alum WTR amendments also significantly decreased CaCl2-extractable soil P levels in surface soils (0 to 20 cm) and in 0 to 30 cm depth samples compared to unamended control soils. In Washington, a multi-laboratory (10 labs) extraction study was implemented to quantify error associated with WEP protocols on 20 manures and biosolids. A supplemental runoff study was conducted with 15 of the manures and biosolids to assess whether protocol changes affect the prediction of dissolved P in runoff. A 10:1 extraction ratio had the highest variability when extract P was determined by colorimetry and was too low to obtain uniform suspensions and sufficient extract volumes for some dairy manures and biosolids. Results of the runoff study showed WEP to be correlated with dissolved P in runoff for all methods, whether derived from a single laboratory (r = 0.79 to 0.93) or multiple laboratories (r = 0.56 to 0.83). As the strongest correlations with dissolved P in runoff were associated with a 100:1 extraction ratio and the fewest laboratory complaints were associated with this ratio, this study points to a single recommended protocol for measuring WEP in manures and biosolids. The effects on soil quality attributes of long term (since 2000) annual applications of various organic residuals to a Virginia highly weathered, Piedmont soil has continued to be investigated. The effects of various compost types (yardwaste-poultry litter, biosolids-woodchips) and rates (0.3x and 1x agronomic N rate), poultry litter (1x annual agronomic N rate), and commercial fertilizer (annually applied according to soil testing laboratory recommendations) on soil C and humic substances, bulk density, and water-holding capacity and soybean physiological function (as an indicator of environmental stress amelioration) were measured. Total soil C, humic substances, and water-holding capacity was higher and bulk density was lower in the soils that received composts than poultry litter at estimated agronomic N rates, but yields were similar for fertilizer, poultry litter, and composts when applied at rates estimated to supply recommended N rates. A Virginia Piedmont soil that received five rates (up to 210 Mg/ha) of a high metal-containing biosolid in 1984 began exhibiting Al and/or Zn toxicity and/or Fe deficiency and yield depression in corn as soil pH declined to <5 ten years after biosolids application. Following liming of the soil to pH >6 in 1999, no effect of biosolid rate on Cd, Cu, Ni, and Zn phytotoxicity using radish and lettuce as bioassay crops were evident, even as soil pH dropped to between 5.2 and 5.4 in 2005. Lime stabilized biosolids were employed in a large (16 plots, 0.5 ha/plot) mine soil reconstruction project in central Virginia designed to evaluate soil reconstruction strategies for prime farmlands disturbed by mineral sands mining. First-year yields (Zea mays) from 2005 indicated that 78 Mg/ha biosolids combined with deep tillage treatments were superior to topsoil (15 cm) return. Rainfall simulations in Florida, with soil samples from field studies begun in 1998 (Jacobs and Tippen  MI cooperators) will address WTR impacts on P mobility and the long-term stability of WTR-immobilized P. Soil samples from the Michigan plots were subjected to various measures of P-lability, including extraction with various common soil extractants and a 32P-based technique. All data collected to date suggest that WTR-immobilized P is a stable, long-term product. Thus, the lab data suggest that WTRs can serve as permanent immobilizers of P in high P soils, and that the immobilized-P remains stable unless the soil pH falls below 4. Laboratory studies, including small column leaching studies, also demonstrate the usefulness of WTRs (an Al-WTR) in controlling P leaching from a Spodosol surface horizon highly impacted with P from years of manure application. The studies clearly show, however, that the WTR must be placed in close proximity to the soluble-P source to be effective. The Colorado State University members examined the effects of gypsum, acidic gypsum, sulfuric acid, and elemental S with and without 90 Mg woodchips ha-1 on the removal of excess Na and pH depression in a bauxite residue (Al-processing waste; pH = 10.0). Materials were placed in 32-L PVC containers and then leached with 8 separate pore volumes of water. The acidic gypsum and acidic gypsum plus woodchips significantly lowered the pH, resulted in the greatest Na, Ca, and Mg leaching, and had a lower sodium adsorption ratio (SAR) compared to all other treatments. Greenhouse experiments at Penn State with manufactured topsoil blends containing three types of spent foundry sand, three types of composted organic materials, and high clay subsoil showed growth of ryegrass (Lolium multiflorum Lam.) was better on manufactured soils than natural topsoil. Trace elements in ryegrass tissue from manufactured soils were less than or not different from those grown in natural soil. Composts had much greater effects than foundry sands on leaching loss of nutrients and trace elements. Acidic coal refuse was mixed with composted manure (3 rates) and fresh manure plus paper mill sludge to adjust C:N ratio from 7:1 (manure only) to 40:1. Switchgrass (Panicum virgatum) did not survive on un-amended refuse, and growth was very poor with limestone and fertilizer. Growth increased with compost application and increased even more with paper mill sludge amendment. Almost no nitrate was lost in leachates from compost treatments and large amounts of nitrate (>180 mg per column) were lost from manure only treatments. Paper mill sludge reduced nitrate loss with a C:N ratio of 30:1 giving the least loss (25 mg per column). Leaching of P was largest from manure only and was greatly reduced by composting or addition of paper mill sludge. When applied at a common total P rate, P losses generally decreased in the order: poultry and swine manures > dairy manure and BPR biosolids > non-BPR biosolids. The P concentrations in runoff from biosolids-amended soils depend on the types of wastewater and solids processing methods used to generate the biosolids. Some biosolids types (e.g., BPR products) resulted in higher runoff P concentrations than dairy manure applied at the same plant available N rate. Other biosolids, because of additions of Al and/or Fe during wastewater treatment, or through solids processes like heat drying, produced runoff P losses indistinguishable from un-amended soil treatments. Objective 2: Evaluate the ability of in situ treatment of contaminated soil with residuals to reduce chemical contaminant bioavailability and reduce toxicity. At Ohio State University, arsenate or lead sorbed to ferrihydrite, corundum, and birnessite model soil oxide minerals were used to simulate possible effects of ingestion of soil contaminated with As(V) or Pb(II) sorbed to oxide mineral surfaces. Arsenate or lead sorbed to ferrihydrite, corundum, or birnessite were placed in a simulated gastrointestinal tract (in vitro) to ascertain the bioaccessibility of As(V) or Pb(II) and changes in As(V) or Pb(II) surface speciation caused by the gastrointestinal system. The speciation of As or Pb was determined using Extended X-ray Absorption Fine Structure (EXAFS) analysis and X-ray Absorption Near Edge Spectroscopy (XANES). Results for As(V) sorbed to ferrihydrite and corundum suggest that the bioaccessibility of As(V) is related to the As(V) concentration, and the As(V) adsorption maximum. The results for As(V) sorbed birnessite suggest that birnessite can reduce the bioaccessibility of As(V) in contaminated soil and the desorption of the As(V) from the birnessite surface is the mode of bioaccessibility. Sorption of Pb(II) was significant for all the model oxides used. Caution should be used before using these materials to remediate a soil where incidental ingestion is an important exposure pathway. The Virginia contingent has continued to work at a large (200 ha) acid sulfate soil remediation site in northern Virginia, where one-time applications of lime stabilized biosolids at rates ranging from 100 to 225 Mg/ha have maintained soil pH > 6.0 for three full years following application to soils of pH 3.0. Water quality monitoring indicates that N losses to surface waters were negligible beyond the application year (2002). Biosolids increased the percent seedling survival in Arkansas soil contaminated with 5% crude oil for pearl millet and sudangrass. Compared to the Milorganite® treatment and the unamended control, biosolid addition increased shoot and root biomass. Root length, surface area, volume, and diameter were also increased when crude oil contaminated soil was amended with biosolids. Evaluation of the influence of crude oil and organic amendments on soil chemical properties is currently underway. Greenhouse studies are underway in Florida to evaluate the phytoavailability of biosolids-P to a representative pasture grass. The studies are similar to previously completed studies with multiple biosolids representing national biosolids-processing methods. The current studies focus on biosolids produced and/or marketed in FL, and emphasize those materials with high values of water-extractable P (WEP), especially biological nutrient removal (BPR) materials. Biosolids-P phytoavailability is being compared to fertilizer-P phytoavailability. In a related study in Ohio, large amounts of amorphous aluminum or iron oxide in drinking water treatment residuals (WTR) can result in a large phosphorus (P) sorption capacity (Pmax). The strong relationship between amorphous Al (Alox) and Langmuir P sorption capacity (Pmax) in WTR was shown to be a useful tool for determining Pmax without the onus of the multipoint batch equilibrations necessary for the Langmuir model. A new method was developed that accurately determines WTR Pmax from Alox. A cooperative study among members at University of Washington and US EPA examined changes in As and Pb bioavailability after the addition of high-iron compost. Following a lab study, field plots were established on orchard soils at the Washington State University Experiment station in Wenatchee, WA. Iron, in the form of Fe grit and ferric chloride were added to biosolids prior to composting. The study was set up in May, 2005. No changes were seen in Pb availability, however, there was a reduction in As availability with the addition of high Fe compost at higher application rates. The failure of the amendments to reduce Pb availability in the field study contrasted with the reductions in availability observed in the lab incubation. In the lab incubation, addition of 10% high Fe biosolids compost from Philadelphia reduced Pb availability for all soils tested. In an attempt to determine why field composts were less effective than those used in a lab study, an additional lab incubation was conducted using a Philadelphia compost along side high Fe composts from the field study. Soils from the control plots of the field study were used. Again, a significant reduction in Pb availability with the addition of Philadelphia compost was observed. We hypothesized that the different reactivates of the materials was related to the form of iron in the composts. A soil extract to assess the reactive or amorphous Fe oxides showed that a significantly higher fraction of the total Fe in the Philadelphia compost fell into this fraction. As part of the lab incubation, compost samples were analyzed using Mossbauer spectroscopy by Kirk Scheckel at US EPA NMRML. Here the Fe in both the Philadelphia compost and a low Fe biosolids compost were found to consist at least in part of amorphous oxides, potentially associated with organic matter. This, in combination with our field results suggest that the alternating aerobic and anaerobic stages of wastewater treatment produces a highly reactive adsorptive surface. This type of surface was not reproducible in field tested composts. In Indiana, a team of researchers has been evaluating the addition of various amendments to soils to reduce bioavailability of metals in highly contaminated soils. Included in these amendments are manganese oxides, phosphates, and biosolids. Bioavailability is being evaluated using indicator species including earthworms, plant seedlings, and microbes (respiration). Bioaccessibility is being determined by water solubility, in vitro gastrointestinal (IVG) test, and physiologically based extraction test (PBET). Sites being evaluated include military bases and former industrial locations. Objective 3: Predict the long-term bioavailability and toxicity of nutrients, trace elements, and organic constituents in residual-amended agricultural and contaminated soils. A field study established in Michigan investigating the environmental fate of various pollutants (primarily 503 pollutants) contained in two N-Viro alkaline-stabilized products made from East Lansing biosolids cake (N-Viro Soil) and swine manure (NureSoil) was completed in spring, 2005, with final sampling of soils with depth. Yields of soybeans decreased significantly 2002 and 2003 at the highest N-Viro Soil application rate compared to the control and other treatments, but corn yields were not significantly different between treatments. The decreased soybean yields were attributed to toxic levels of B added by the very high, non-agronomic rate of N-Viro Soil, based on high B test levels found in surface soils. A new Florida project was funded by EPA to evaluate the Fate of Triclocarban (TCC) in Sludge-Amended Soils. The project is joint effort between UF personnel and researchers at Proctor and Gamble (Cinn. Lab). Triclocarban is anti-microbial (similar to triclorsan, TCS), and is a common ingredient in various bar soaps. About 300,000 to 500,000 kg of the compound is used each year in the US, and limited data suggest that TCC concentrations in some activated sludges can reach ~40 mg/kg. Environmentally-relevant concentrations are expected to persist in sludge-amended soils even after dilutions associated with soil application at agronomic rates. The study will examine a variety of fates and potential pathways for human, environmental, and soil microbial impacts of TCC. Researchers in Colorado studied the long-term effects of biosolids land application to a dryland winter wheat agroecosystem on barium accumulation and vertical movement. Littleton/Englewood, CO biosolids were applied every other year from 1982 through 2002 at rates from 0 to 26.8 dry Mg ha-1. Extractions with 4M HNO3 and AB-DTPA were used from 1988 through 2003; on 2003 soils, a sequential extraction procedure was employed to determine identify labile through resistant Ba fractions and utilized scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) to identify Ba mineral phases. The 4 M HNO3 extractable Ba increased while AB-DTPA extractable Ba decreased in the soil surface, but biosolids did not affect the subsurface. The SEM-EDS results verified soil surface Ba-S associations, most likely BaSO4. Sequential extraction results suggested increasing BaCO3 precipitation in the subsoil, indicating that biosolids-borne or natural Ba may be transported vertically.