Browsing by Subject "soil"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Case studies and evidence-based approaches to addressing urban soil lead contamination
    (Elsevier, 2017-08) Laidlaw, Mark A. S.; Filippelli, Gabriel M.; Brown, Sally; Paz-Ferreiro, Jorge; Reichman, Suzie M.; Netherway, Pacian; Truskewycz, Adam; Ball, Andrew S.; Mielke, Howard W.; Earth Science, School of Science
    Urban soils in many communities in the United States and internationally have been contaminated by lead (Pb) from past use of lead additives in gasoline, deterioration of exterior paint, emissions from Pb smelters and battery recycling and other industries. Exposure to Pb in soil and related dust is widespread in many inner city areas. Up to 20–40% of urban children in some neighborhoods have blood lead levels (BLLs) equal to or above 5 μg per decilitre, the reference level of health concern by the U.S. Centers for Disease Control. Given the widespread nature of Pb contamination in urban soils it has proven a challenge to reduce exposure. In order to prevent this exposure, an evidence-based approach is required to isolate or remediate the soils and prevent children and adult's ongoing exposure. To date, the majority of community soil Pb remediation efforts have been focused in mining towns or in discrete neighborhoods where Pb smelters have impacted communities. These efforts have usually entailed very expensive dig and dump soil Pb remediation techniques, funded by the point source polluters. Remediating widespread non-point source urban soil contamination using this approach is neither economical nor feasible from a practical standpoint. Despite the need to remediate/isolate urban soils in inner city areas, no deliberate, large scale, cost effective Pb remediation schemes have been implemented to isolate inner city soils impacted from sources other than mines and smelters. However, a city-wide natural experiment of flooding in New Orleans by Hurricane Katrina demonstrated that declines in soil Pb resulted in major BLL reductions. Also a growing body of literature of smaller scale pilot studies and programs does exist regarding low cost efforts to isolate Pb contaminated urban soils. This paper reviews the literature regarding the effectiveness of soil Pb remediation for reducing Pb exposure and BLL in children, and suggests best practices for addressing the epidemics of low-level Pb poisoning occurring in many inner city areas.
  • Thumbnail Image
    Item
    Convolutional neural network model for soil moisture prediction and its transferability analysis based on laboratory Vis-NIR spectral data
    (Elsevier, 2021-12) Chen, Yu; Li, Lin; Whiting, Michael; Chen, Fang; Sun, Zhongchang; Song, Kaishan; Wang, Qinjun; Earth Sciences, School of Science
    Laboratory visible near infrared reflectance (Vis-NIR, 400–2500 nm) spectroscopy has the advantages of simplicity, fast and non-destructive which was used for SM prediction. However, many previously proposed models are difficult to transfer to unknown target areas without recalibration. In this study, we first developed a suitable Convolutional Neutral Network (CNN) model and transferred the model to other target areas for two situations using different soil sample backgrounds under 1) the same measurement conditions (DSSM), and 2) under different measurement conditions (DSDM). We also developed the CNN models for the target areas based on their own datasets and traditional PLS models was developed to compare their performances. The results show that one dimensional model (1D-CNN) performed strongly for SM prediction with average R2 up to 0.989 and RPIQ up to 19.59 in the laboratory environment (DSSM). Applying the knowledge-based transfer learning method to an unknown target area improved the R2 from 0.845 to 0.983 under the DSSM and from 0.298 to 0.620 under the DSDM, which performed better than data-based spiking calibration method for traditional PLS models. The results show that knowledge-based transfer learning was suitable for SM prediction under different soil background and measurement conditions and can be a promising approach for remotely estimating SM with the increasing amount of soil dataset in the future.
  • Thumbnail Image
    Item
    EFFECT OF SOIL TYPE AND HYDROLOGY ON THE COMPOSITION OF NITROGEN GASES EMITTED FROM RIPARIAN BUFFERS
    (Office of the Vice Chancellor for Research, 2012-04-13) Bebinger, Lori; Jacinthe, Pierre-Andre
    The US Corn Belt States are the leading contributors to nitrate (NO3-) enrichment and the so-called dead-zone in the Gulf of Mexico. Located at the interface between agricultural fields and surface water bodies, riparian buffers have shown great capacity to remove NO3- from agricultural runoff, and thus reduce fertilizer N export to streams. Under the right conditions (organic carbon, moist to wet soils), riparian soil microbes can convert NO3- into nitrous oxide (N2O) and dinitrogen (N2).However, from an air quality standpoint, a low N2O production relative to N2 (mole fraction of N2O) would be preferred because N2O contributes to the greenhouse effect and depletion of the ozone layer, With the hypothesis that frequent water saturation is favorable to the reduction of N2O into N2 (thus a low N2O mole fraction), a study was conducted to identify controlling factors of N2O mole fraction across various riparian buffers, including well-drained (WR), artificially-drained (LWD), and poorly-drained (SF) sites. The relative production of N2O and N2 was measured in the laboratory using the acetylene (C2H2) block technique. In the absence of C2H2, there was no difference in N2O production rate among the sites. However, in the presence of C2H2, N2O production at SF (30 μg N2O kg-1 soil h-1) was much higher than at the other sites (3.31 at LWD and 8.42 at WR). Conversely, the N2O mole fraction at SF (0.11) was lower than at WR (0.28). These results are consistent with the greater soil moisture, and higher total soil organic C at SF compared to the other sites. The low N2O production at LWD is probably due to the presence of tile drains and infrequent soil saturation. Future studies will examine the impact of tile-drain on the composition of N gases from these types of buffers.
  • Thumbnail Image
    Item
    Microbial Degradation of Gasoline in Soil: Effect of Season of Sampling
    (Elsevier, 2015-06) Turner, Dee A.; Pichtel, J.; Rodenas, Y.; McKillip, John L.; Goodpaster, John V.; Department of Chemistry & Chemical Biology, IU School of Science
    In cases where fire debris contains soil, microorganisms can rapidly and irreversibly alter the chemical composition of any ignitable liquid residue that may be present. In this study, differences in microbial degradation due to the season in which the sample is collected was examined. Soil samples were collected from the same site during Fall, Winter, Spring and Summer and the degradation of gasoline was monitored over 30 days. Predominant viable bacterial populations enumerated using real-time PCR and reverse transcriptase polymerase chain reaction (RT-PCR) enumeration revealed the predominant viable bacterial genera to be Alcaligenes, Bacillus, and Flavobacterium. Overall, the compounds most vulnerable to microbial degradation are the n-alkanes, followed by the mono-substituted alkylbenzenes (e.g., toluene, ethylbenzene, propylbenzene and isopropylbenzene). Benzaldehyde (a degradation product of toluene) was also identified as a marker for the extent of biodegradation. Ultimately, it was determined that soil collected during an unusually hot and dry summer exhibited the least degradation with little to no change in gasoline for up to 4 days, readily detectable n-alkanes for up to 7 days and relatively high levels of resilient compounds such as o-xylene, p-xylene and 1,3,5-trimethylbenzene. These results demonstrate, however, that prompt preservation and/or analysis of soil evidence is required in order to properly classify an ignitable liquid residue.
  • Thumbnail Image
    Item
    The Spatial Relationship Between Septic System Failure and Environmental Factors in Washington Township, Marion County, Indiana
    (2019-04) Hanson, Brian L.; Johnson, Daniel P.; Lulla, Vijay; Bein, Frederick L.
    Underground septic systems thrive or fail based on the relationship with their local environment. This paper explores ways environmental variables such as soil type, tree roots, degree of slope, and impervious surfaces affect on-site wastewater treatment systems. It also discusses the effects each of these variables may have on a septic system, and the resulting impact a compromised system may have on the surrounding environment. This research focuses on an approximately 20 square mile area of central Washington Township in Marion County, Indiana. This area of central Indiana contains a large septic system owning population in a sampling of different environments such as wooded areas, hilly areas, and a variety of different soil types.