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PubMed2005

Considerations for the use of soil ecological classification and assessment concepts in soil protection.

In comparison with other environmental compartments, the protection of soil was identified relatively late as an important issue. Even later, policy makers and the general public considered the ecological functions of the soil. However, recently, the central role of these functions, as well as the importance of the soil organism community, has become obvious in several countries in Europe and in the European Union itself. In this contribution, basic considerations referring to use of ecological endpoints for the classification and assessment of soils are discussed. The article begins with two goals of protection: to protect soil so that it can function and to protect soil as a habitat for organisms necessary for these functions. Afterward, the quality of soil from is discussed from a biological point of view. Finally, on the basis of experience from limnology and botany, recommendations are made for monitoring programs. In other articles of this series, details of the entire approach to ecological classification and assessment are outlined.

Animals↗

PubMed2005

The use of predatory soil mites in ecological soil classification and assessment concepts, with perspectives for oribatid mites.

Gamasina are the main predators among the soil mesofauna and, therefore, have a crucial position in the soil food web and contribute significantly to energy and matter turnover. Ecological concepts including predatory mites in soil assessment have not yet been established, while standardized sampling, extraction, and conservation methods are available. There are reliable keys for Europe that cover most families. Few species in low dominance ranks correlate well with soil properties like soil texture and pH. Meaningful endpoints for soil assessment are community parameters that are based on the life history of the species (e.g., Maturity Index). It has been shown that the predatory mites, as well as the oribatids as a second common and widespread group of mites, fit well into a soil assessment concept comparable to RIVPACS, which was established for aquatic systems. Perspectives for future research are the development of a computer-aided identification key and the creation of a database with information on the ecology and biogeography of important species.

Animals↗

PubMed2005

Effects of polycyclic aromatic hydrocarbons on germination and subsequent growth of grasses and legumes in freshly contaminated soil and soil with aged PAHs residues.

The relevance of germination trials for screening plants that may have potential for use in the phytoremediation of PAH contaminated land was evaluated. The germination and subsequent growth of 7 grass and legume species were evaluated in soil spiked with a pure PAH mixture or coal tar and soil from a former coking plant heavily contaminated with aged PAHs. None of these treatments adversely affected germination of the plants. However, apart from Lolium perenne all species exhibited reduced growth in the coking plant soil after 12 weeks growth when compared to the untreated soil. In the coal tar spiked soil 4 out of the 7 species showed reduced growth, as did 3 out of the 7 in the soil spiked with a mixture of 7 PAHs. Therefore, germination studies alone would not predict the success of subsequent growth of the species tested in the ranges of soil PAH levels studied.

Biodegradation, Environmental↗

PubMed2004

Cryptosporidium parvum oocyst inactivation in field soil and its relation to soil characteristics: analyses using the geographic information systems.

The need exists to understand the environmental parameters that affect inactivation of Cryptosporidium parvum oocysts in soil under field conditions. The inactivation of C. parvum oocysts placed in the natural environment was studied at a dairy farm in western New York State, USA. Seventy sampling points were arranged in a grid with points 150 m apart using the Geographic Information System. The sampling points were distributed among three distinct areas: woodland, corn field and pasture. Purified oocysts were inoculated into chambers filled with soil from each sampling point, and buried in the surface of each respective sampling point. To compare C. parvum oocyst survival with another organism known to survive environmental stresses, Ascaris suum eggs were also placed in soil contained in chambers and buried at the same sampling points as the oocysts. As controls oocysts and eggs in distilled water were also placed at each sampling point. Oocyst and egg viability, soil pH and percent gravimetric water content were measured at all sampling points at 0, 60 and 120 day sampling periods. Soil organic content was determined for each sampling point. At 120 days after placement, mean viability of C. parvum oocysts was 10% although at a few sampling points, 30% of oocysts were still potentially infective; whereas 90% of A. suum eggs were viable at all sampling points. Statistically significant differences were not observed among the three different sampling areas, and no statistically significant predictors were found by regression analysis. Results exemplified the heterogeneity of soil parameters and oocyst viability across a landscape; such results make predictive models for C. parvum inactivation problematical. The long-term survival of C. parvum oocysts in soil under field conditions, as this study demonstrated, emphasizes their potential as a risk to contaminate surface waters.

Agriculture↗

PubMed1999

Laboratory treatability testing of soils contaminated with lead and PCBs using particle-size separation and soil washing.

A soil treatability study was conducted using particle-size separation and soil washing to reduce the volume of material contaminated with polychlorinated biphenyls (PCBs) and lead at a Superfund site. Soil washing using surfactant was effective at removing 95% of PCBs into fine material and residual wash water. Results indicate that almost 80% of the material contaminated with up to 140 mg/kg PCBs could be treated to concentrations below 10 mg/kg using soil washing with surfactant. There did not appear to be a difference in lead removal using either particle size separation or soil washing, although the lead data have high uncertainty because of soil heterogeneity. Lead concentrations in soil were reduced from as high as 1700 to < or =150 mg/kg and from 560 to < or =220 mg/kg in about half of the material using particle size separation.

Decontamination↗

PubMed2001

Effect of pedological characteristics on aqueous soil extraction recovery and tert-butyldimethylsilylation yield for gas chromatography-mass spectrometry of nerve gas hydrolysis products from soils.

Detection and identification of alkyl methylphosphonate (RMPA) and methylphosphonate (MPA) are performed to verify the existence of nerve gases by gas chromatography-mass spectrometry (GC-MS) after tert-butyldimethylsilylation (TBDMS). However, it is sometimes difficult to detect RMPA and MPA in soils. This study examines the relationship between the pedological characteristics and the aqueous extraction recoveries and TBDMS derivatization yields of ethyl-, isopropyl- and pinacolyl methylphosphonate and MPA for 21 soil samples. The aqueous extraction recoveries were measured directly by capillary electrophoresis. Andosols showed low extraction recoveries, while Regosols and Fluvisols showed high recoveries. RMPA were extracted with higher recoveries than MPA from all soils. MPA could not be extracted from Andosols. Within the pedological characteristics, phosphate absorption coefficients showed a strong negative correlation with the extraction recoveries of all phosphonates. The levels of RMPA and MPA in aqueous soil extracts were also determined for eight soils by GC-MS after TBDMS. Compared to the aqueous extraction recoveries, the yields of TBDMS derivatives were low. Strong anion exchange led to a significant improvement in derivatization yields. The efficiencies of TBDMS derivatization were inversely correlated with the levels of alkaline earth metals extractable from soils when the three soils that possessed high total carbon were excluded.

Chemical Warfare Agents↗

PubMed2003

Chemical-specific representation of air--soil exchange and soil penetration in regional multimedia models.

In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil layers with different properties but a fixed boundary condition at the air-soil surface. The soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, groundwater, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo[a]pyrene, MTBE, TCDD, and tritium.

Air Pollutants↗

PubMed2006

Freely dissolved concentrations of PAHs in soil pore water: measurements via solid-phase extraction and consequences for soil tests.

Freely dissolved pore water concentrations are difficult to assess in complex matrixes such as soils or sediments. In this study, a negligible-depletion partitioning-based sampling technique was applied to measure freely dissolved pore water concentrations. A poly(dimethylsiloxane) (PDMS)-coated glass fiber was exposed to a slurry of a soil spiked with several PAHs at concentrations ranging from 2 to 2000 mg/kg. PAH-concentrations in the PDMS coating increased linearly with the total soil concentration until a certain maximum was reached. Freely dissolved pore water concentrations were calculated using PDMS-water partition coefficients, and the calculated maximum pore water concentrations corresponded with the aqueous solubility of the tested compounds. Furthermore, the sampling technique is very sensitive because it can detect freely dissolved pore water concentrations in the ng/L range for the tested PAHs. Freely dissolved pore water concentrations are an important parameter for the exposure of organisms in soil. Saturation of the pore water with increasing soil concentrations should therefore be considered in soil toxicity testing. Sorption coefficients that were calculated from freely dissolved concentrations were slightly higher than estimates based on octanol-water partition coefficients. These differences are discussed in relation to the effects of dissolved organic matter in soil pore water on the determination of sorption coefficients.

Adsorption↗

PubMed2003

Fungi are the predominant micro-organisms responsible for degradation of soil-buried polyester polyurethane over a range of soil water holding capacities.

AIMS: To investigate the relationship between soil water holding capacity (WHC) and biodegradation of polyester polyurethane (PU) and to quantify and identify the predominant degrading micro-organisms in the biofilms on plastic buried in soil. METHODS AND RESULTS: High numbers of both fungi and bacteria were recovered from biofilms on soil-buried dumb-bell-shaped pieces of polyester PU after 44 days at 15-100% WHC. The tensile strength of the polyester PU was reduced by up to 60% over 20-80% soil WHC, but no reduction occurred at 15, 90 or 100% soil WHC. A PU agar clearance assay indicated that fungi, but not bacteria were, the major degrading organisms in the biofilms on polyester PU and 10-30% of all the isolated fungi were able to degrade polyester PU in this assay. A 5.8S rDNA sequencing identified 13 strains of fungi representing the three major colony morphology types responsible for PU degradation. Sequence homology matches identified these strains as Nectria gliocladioides (five strains), Penicillium ochrochloron (one strain) and Geomyces pannorum (seven strains). Geomyces pannorum was the predominant organism in the biofilms comprising 22-100% of the viable polyester PU degrading fungi. CONCLUSIONS: Polyester PU degradation was optimum under a wide range of soil WHC and the predominant degrading organisms were fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: By identifying the predominant degrading fungi in soil and studying the optimum WHC conditions for degradation of PU it allows us to better understand how plastics are broken down in the environment such as in landfill sites.

Biodegradation, Environmental↗

PubMed1983

[Effect of application of a herbicide propyzamide into the soil by study of mineralization of glucose 14C(U) and distribution of radioactivity in various fractions of the soil (laboratory and open field tests)].

The effects of the herbicide PROPYZAMIDE are studied in laboratory and field conditions. The modifications involved are characterized by measurement of 14C-glucose mineralization and radioactivity incorporation into the soil fractions. In laboratory conditions, temperature and moisture are kept stable and the experiment is performed during less than 24 hours. In these conditions, Kerb 50 (commercial formulation of propyzamide) and the emulsifier (material used in propyzamide formulation) exert little effect on 14CO2 evolution. In field conditions, propyzamide andKerb 50 are applied once at two different doses: at field rate (1,5 kg/ha) and twentyfold this rate. Essays are duplicated. The herbicide (propyzamide in Celanol and Kerb 50) and the emulsifiers alone (Celanol and the material used in propyzamide formulation) are applied on the soil surface (application date: 3.02.81). Two weeks later and then every month during four months, samples are taken to the depth of about 5 cm (Propyzamide migrates very slowly in the first centimeters of the soil). The characterization experiment is performed on 10 g soil samples by 14C-glucose incubation at 28 degrees C during two hours. 14CO2 evolved is measured after incubation and acidification with HCl. Then radioactivity distribution in the soil is counted after chemical fractionation of soil. This distribution is about 10-16.5% as 14CO2, 22-37% in the acid-soluble fraction, 10-25% in the alkali-soluble fraction and 15-45% in the human fraction (measured as 14CO2 evolved after combustion). This distribution is little modified by the herbicides or the emulsifiers but its evolution is significantly related to environmental conditions (temperature). Nevertheless a few modifications are observed. They can be due to the herbicide propyzamide itself but the emulsifiers and the degradation products of propyzamide can also influence the measurement (After forty days in the soil, 70-95% of the starting active ingredient have disappeared). They can also be a result of the initial effects of the products (modification of the microflora and of the environment).

Benzamides↗

PubMed2003

Tree species of the Central Amazon and soil moisture alter stable isotope composition of nitrogen and oxygen in nitrous oxide evolved from soil.

The use of stable isotopes of N and O in N2O has been proposed as a way to better constrain the global budget of atmospheric N2O and to better understand the relative contributions of the main microbial processes (nitrification and denitrification) responsible for N2O formation in soil. This study compared the isotopic composition of N2O emitted from soils under different tree species in the Brazilian Amazon. We also compared the effect of tree species with that of soil moisture, as we expected the latter to be the main factor regulating the proportion of nitrifier- and denitrifier-derived N2O and, consequently, isotopic signatures of N2O. Tree species significantly affected delta15N in nitrous oxide. However, there was no evidence that the observed variation in delta15N in N2O was determined by varying proportions of nitrifier- vs. denitrifier-derived N2O. We submit that the large variation in delta15N-N2O is the result of competition between denitrifying and immobilizing microorganisms for NO3(-). In addition to altering delta15N-N2O, tree species affected net rates of N2O emission from soil in laboratory incubations. These results suggest that tree species contribute to the large isotopic variation in N2O observed in a range tropical forest soils. We found that soil water affects both 15N and 18O in N2O, with wetter soils leading to more depleted N2O in both 15N and 18O. This is likely caused by a shift in biological processes for 15N and possible direct exchange of 18O between H2O and N2O.

Brazil↗

PubMed1997

Identification of an accurate soil suspension/dispersion modeling method for use in estimating health-based soil cleanup levels of hexavalent chromium in chromite ore processing residues.

The primary health concern associated with chromite ore processing residues (COPR) at sites in Hudson County, NJ, is the inhalation of Cr(VI) suspended from surface soils. Since health-based soil standards for Cr(VI) will be derived using the inhalation pathway, soil suspension modeling will be necessary to estimate site-specific, health-based soil cleanup levels (HBSCLs). The purpose of this study was to identify the most appropriate particulate emission and air dispersion models for estimating soil suspension at these sites based on their theoretical underpinnings, scientific acceptability, and past performance. The identified modeling approach, the AP-42 particulate emission model and the fugitive dust model (FDM), was used to calculate concentrations of airborne Cr(VI) and TSP at two COPR sites. These estimated concentrations were then compared to concentrations measured at each site. The TSP concentrations calculated using the AP-42/FDM soil suspension modeling approach were all within a factor of 3 of the measured concentrations. The majority of the estimated air concentrations were greater than the measured, indicating that the AP-42/FDM approach tends to overestimate on-site concentrations. The site-specific Cr(VI) HBSCLs for these two sites calculated using this conservative soil suspension modeling approach ranged from 190 to 420 mg/kg.

Chromium↗

PubMed2000

Heavy metals in urban soils of East St. Louis, IL, Part I: Total concentration of heavy metals in soils.

The city of East St. Louis, IL, has a history of abundant industrial activities including smelters of ferrous and non-ferrous metals, a coal-fired power plant, companies that produce organic and inorganic chemicals, and petroleum refineries. A protocol for soil analysis was developed to produce sufficient information on the extent of heavy metal contamination in East St. Louis soils. Soil cores representing every borough of East St. Louis were analyzed for heavy metals--As, Cd, Cu, Cr, Hg, Ni, Pb, Sb, Sn, and Zn. The topsoil contained heavy metal concentrations as high as 12.5 ppm Cd, 14,400 ppm Cu, ppm quantities of Hg, 1860 ppm Pb, 40 ppm Sb, 1130 ppm Sn, and 10,360 ppm Zn. Concentrations of Sb, Cu, and Cd were well correlated with Zn concentrations, suggesting a similar primary industrial source. In a sandy loam soil from a vacated rail depot near the bank of the Mississippi River, the metals were evenly distributed down to a 38-cm depth. The clay soils within a half-mile downwind of the Zn smelter and Cu products company contained elevated Cd (81 ppm), Cu (340 ppm), Pb (700 ppm), and Zn (6000 ppm) and displayed a systematic drop in concentration of these metals with depth. This study demonstrates the often high concentration of heavy metals heterogeneously distributed in the soil and provides baseline data for continuing studies of heavy metal soil leachability.

Hydrogen-Ion Concentration↗

PubMed2006

Root turnover and relocation in the soil profile in response to seasonal soil water variation in a natural stand of Utah juniper (Juniperus osteosperma).

Juniper species are noted for long-lived foliage, low and persistent gas exchange activity and drought tolerance. Because leaves and roots of the same species are thought to be similar in structure and life history, we hypothesized that Juniperus osteosperma (Torr.) Little (Utah juniper) fine roots would reflect the persistent aboveground foliage characteristic of this species. We monitored fine roots, less than 1 mm in diameter, by minirhizotron imaging to a depth of 150 cm over two growing seasons from April 2002 to December 2003. We measured fine root numbers, lengths and diameters, and noted the time of birth and death of root segments. We correlated our root data with soil water potential measured by thermocouple psychrometry and ecosystem evapotranspiration measured by ecosystem eddy flux. Median fine root lifespan, determined by the Kaplan-Meier product-limit method, was about one year, much less than foliage lifespan estimates of more than five years. Yet, roots of juniper live much longer than those of other Great Basin species. The median survivorship of shallow and deep roots was 144 and 448 days, respectively. Production of new roots was observed during periods of favorable soil water potential and there was a seasonal progression of increased new roots and root length during the warm season toward lower soil depths with root loss in the upper soil layers. This was also reflected in water extraction which progressed to greater soil depths later in the warm season. Aboveground, rates of ecosystem evapotranspiration decreased with decreasing soil water potentials in a similar manner in both 2002 and 2003, reflecting the relocation of roots to available water at depth. Juniper exhibited a flexible root depth distribution throughout the 20 months of this study, indicating the potential to respond to shifting soil water resources despite long fine root lifespans.

Climate↗

PubMed1994

Soil permeability as a function of vegetation type and soil water content.

Soil permeability is important for estimating the rate of mass transport of 222Rn through soils and into basements (Nazaroff 1992). We measured permeability and soil water content on a set of nine plots consisting of three plots vegetated with common barley (Hordeum vulgare), three plots vegetated with Russian thistle (Salsola kali), and three bare plots. Soil moisture was consistently highest on the bare plots and lowest on the Russian thistle plots. Plots with vegetation had lower soil water content during the growing season. Permeability was consistently higher on Russian thistle plots. ANOVA showed that both soil water content and presence of Russian thistle had a significant impact on permeability but that presence of barley did not. The effect of vegetation and moisture on permeability may have significant effects on 222Rn transport in soils.

Permeability↗

PubMed1979

Superiority of a soil debris isolation method over a beet seed colonization method for assay of Rhizoctonia solani at high soil inoculum densities.

A quantitative soil debris isolation method (all debris from known weight of soil plated) and a garden beet seed saprophytic colonization method were compared over a 1-year period for assaying Rhizoctonia solani population. Four fields of different soil textures were selected. Within each field four areas of healthy and four areas of diseases (rhizoctonia root and crown rot) sugarbeets were sampled bimonthly from August 1976 until June 1977. The maximum numbers of R. solani colonies obtained by the debris method were 2 per gram of soil in areas of healthy beets, and 11 per gram of soil in areas of diseased sugarbeets. At such high inoculum densities the beet seed colonization method underestimated R. solani populations, because the inoculum per unit of soil exceeded the numbers of beet seeds per unit of soil available for colonization. Modifications of the beet seed method did not significantly alter results of colonization assays. Ranked correlation comparisons of assay methods yielded r = 0.81 for all data.

Mitosporic Fungi↗

PubMed2001

Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time.

The anionic surfactant linear alkylbenzene sulfonate (LAS) may inhibit soil microorganisms and may occur in agricultural soil through the application of sewage sludge. For five microbial parameters (microbial biomass C and the potentials of iron reduction, ammonium oxidation, dehydrogenase activity, and arylsulfatase activity), we compared the effects of aqueous LAS and LAS-spiked sewage sludge added to existing levels of 0, 3, 8, 22, 22, 62, 174, and 488 mg/kg soil (dry wt) in a Danish sandy agricultural soil that was incubated for 5 d to eight weeks. Arylsulfatase activity (measured after four weeks of incubation) was rather insensitive to LAS, with an EC 10 of 222 and more than 488 mg/kg in soil samples treated with aqueous LAS and LAS-spiked sewage sludge, respectively. For the other microbial parameters, the short-term effects (approximately one to two weeks) of aqueous LAS were characterized by an EC10 in the range of 3 to 39 mg/kg. Application of LAS via sewage sludge generally reduced the short-term effects for the microbial parameters, and the EC10 for LAS in sludge-amended soil after approximately one to two weeks of incubation ranged from less than 8 to 102 mg/kg. Recovery potential was seen for most microbial parameters as a result of prolonged incubation, both under conditions of LAS persistence (anaerobic conditions, the iron-reduction test) and LAS depletion (aerobic incubations, all other assays). In conclusion, the short-term inhibitory effects of LAS on soil microbiology were decreased in the presence of sewage sludge and by a prolonged (two to eight weeks) laboratory incubation period.

Alkanesulfonic Acids↗

PubMedDate not supplied

SOIL-SOILN simulations of water drainage and nitrate nitrogen transport from soil core lysimeters.

Water resources protection from nitrate nitrogen (NO3-N) contamination is an important public concern and a major national environmental issue. The abilities of the SOIL-SOILN model to simulate water drainage and nitrate N fluxes from orchardgrass (Dactylis glomerata L.) were evaluated using data from a 3-yr field experiment. The soil is classified as a Hagerstown silt loam soil (fine, mixed, semiactive, mesic Typic Hapludalf). Nitrate losses below the 1-m depth from N-fertilized grazed orchardgrass were measured with intact soil core lysimeters. Five N-fertilizer treatments consisted of a control, urine application in the spring, urine application in the summer, urine application in the fall, and feces application in the summer. The SOIL-SOILN models were evaluated using water drainage and nitrate flux data for 1993-1994, 1994-1995, and 1995-1996. The N rate constants from a similar experiment with inorganic fertilizer and manure treatments under corn (Zea mays L.) were used to evaluate the SOILN model under orchardgrass sod. Results indicated that the SOIL model accurately simulated water drainage for all three years. The SOILN model adequately predicted nitrate losses for three urine treatments in each year and a control treatment in 1994-1995. However, it failed to produce accurate simulations for two control treatments in 1993-1994 and 1995-1996, and feces treatments in all three years. The inaccuracy in the simulation results for the control and feces treatments seems to be related to an inadequate modeling of N transformation processes. In general, the results demonstrate the potential of the SOILN model to predict NO3-N fluxes under pasture conditions using N transformation rate constants determined through the calibration process from corn fields on similar soils.

Agriculture↗