Petroleum residues as water-repellent substances in weathered nonwettable oil-contaminated soils

1999 ◽  
Vol 79 (2) ◽  
pp. 367-380 ◽  
Author(s):  
Julie L. Roy ◽  
William B. McGill ◽  
Marvin D. Rawluk
Keyword(s):  
Soil Water ◽  
Contaminated Soils ◽  
Impact Ionization ◽  
Water Repellency ◽  
Solvent Mixture ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Petroleum Origin ◽  
Soil Hydrophobicity ◽  
Gas Chromatography Mass Spectroscopy

Some soils develop severe water repellency several years or decades following oil contamination. We previously reported on the characteristics of three such soils. Here we report on the characteristics of putative water-repellent substances in them. We examined the effectiveness of various polar, nonpolar and amphiphilic solvents for removal of water-repellent substances in three nonwettable soils. Only the amphiphilic solvent mixture isopropanol/14.8 M ammonia (7:3, vol/vol) (IPA/NH4OH) completely eliminated soil water repellency in all three soils. We thus define putative water-repellent substances as those substances whose removal from soil by IPA/NH4OH removes water repellency. High-resolution CPMAS 13C-NMR spectroscopy and thermal desorption followed by conventional gas chromatography/mass spectroscopy with electron impact ionization (GC/EI/MS) and GC/MS with chemical ionization (GC/CI/MS) were used to characterize extracted putative water-repellent substances. We conclude that: (i) the identified representatives of these substances consist mostly of homologous series of long-chain and polycyclic aliphatic organic compounds; namely, n-fatty acids, n-alkanes, and cycloalkanes, and that (ii) they are of petroleum origin rather than plant or microbial origin. Key words: Soil hydrophobicity, petroleum hydrocarbons, soil water repellency, amphiphilic solvents, crude oil, nonwettable soil

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

Induced uneven spatial distribution of agrochemicals due to preferential flow in water repellent soils and its remediation by surfactant

2020 ◽  
Author(s):  
Felix Abayomi Ogunmokun ◽  
Rony Wallach
Keyword(s):  
Spatial Distribution ◽  
Soil Water ◽  
Soil Profile ◽  
Preferential Flow ◽  
Sandy Soils ◽  
Water Repellency ◽  
Treated Wastewater ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Mediterranean Countries

&lt;p&gt;Soil water repellency is a common feature of dry soils under permanent vegetation and drought conditions. Soil-water hydrology is markedly affected by soil-water repellency as it hinders infiltration, leading to enhanced surface runoff and soil erosion. Although this phenomenon was primarily ascribed to sandy soils, it has been observed in loam, clay, and peat soils in dry and humid regions. One detrimental effect of soil water repellency on plants is the reduction of soil water availability that stems from the non-uniform water retention and flow in preferential pathways (gravity-induced fingers) with relatively dry soil volume among these paths. It was recently discovered that prolonged irrigation with treated wastewater, a widely used alternative in Israel and other Mediterranean countries due to the limited freshwater, triggers soil water repellency which invariably resulted in preferential flow development in the field. Due to climate change events, the use of treated wastewater for irrigation as a means of freshwater conservation is expected to widen, including in countries that are not considered dry.&lt;/p&gt;&lt;p&gt;While a vast amount of research has been devoted to characterizing the preferential flow in water repellent soils, the effect of this flow regime on the spatial distribution of salt and fertilizers in the root zone was barely investigated. Results from a commercial citrus orchard irrigated with treated wastewater that includes the spatial and temporal distribution of preferential flow in the soil profile measured by ERT will be demonstrated. The associated spatial distribution of salinity, nitrate, phosphate, and SAR in the soil profile will be shown as well.&amp;#160; We investigated the efficacy of two nonionic surfactants application to remediate hydrophobic sandy soils both in the laboratory and field. The effect of the surfactant application to the water repellent soils in the orchards on the spatial distribution of soil moisture and the associated agrochemicals will be presented and discussed.&lt;/p&gt;

scholarly journals Eucalyptus reforestation induces soil water repellency

Soil Research ◽  
2015 ◽  
Vol 53 (2) ◽  
pp. 168 ◽  
Author(s):  
L. L. Walden ◽  
R. J. Harper ◽  
D. S. Mendham ◽  
D. J. Henry ◽  
J. B. Fontaine
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Water Movement ◽  
Computer Modelling ◽  
Clay Content ◽  
Water Repellency ◽  
Water Repellent ◽  
Organic Carbon Content ◽  
Soil Water Repellency ◽  
Hydrophobic Compounds

There is an increasing interest in eucalypt reforestation for a range of purposes in Australia, including pulp-wood production, carbon mitigation and catchment water management. The impacts of this reforestation on soil water repellency have not been examined despite eucalypts often being associated with water repellency and water repellency having impacts on water movement across and within soils. To investigate the role of eucalypt reforestation on water repellency, and interactions with soil properties, we examined 31 sites across the south-west of Western Australia with paired plots differing only in present land use (pasture v. plantation). The incidence and severity of water repellency increased in the 5–8 years following reforestation with Eucalyptus globulus. Despite this difference in water repellency, there were no differences in soil characteristics, including soil organic carbon content or composition, between pasture and plantation soils, suggesting induction by small amounts of hydrophobic compounds from the trees. The incidence of soil water repellency was generally greater on sandy-surfaced (<10% clay content) soils; however, for these soils 72% of the pasture sites and 31% of the plantation were not water repellent, and this was independent of measured soil properties. Computer modelling revealed marked differences in the layering and packing of waxes on kaolinite and quartz surfaces, indicating the importance of interfacial interactions in the development of soil water repellency. The implications of increased water repellency for the management of eucalyptus plantations are considered.

scholarly journals Effects of a Canary pine forest wildfire (Tenerife, Canary Islands, summer 2007) on selected soil properties and their relationship with short- to medium-term soil water repellency .

2014 ◽  
Vol 2 ◽  
Author(s):  
Alexis Hernández ◽  
Natalia Rodríguez ◽  
Marcelino del Arco ◽  
Carmen Dolores Arbelo ◽  
Jesús Notario del Pino ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Forest Fires ◽  
Sampling Site ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Pine Forest ◽  
Soil Water Repellency ◽  
Soil Hydrophobicity ◽  
The Impact

Forest fires modify the soil environment, often triggering severe soil degradation. In this paper, we studied the impact of a large northern Tenerife Canariy pine forest wildfire on a set of relevant soil properties, focusing on their evolution in time and relationship with soil water repellency. To do this, soils were sampled at four sites (burned and non-burned) and several soil physical and chemical parameters were measured. The results show significant variations for soil pH, electric conductivity (CE<sub>1:5</sub>), and NH<sub>4</sub><sup>+</sup>-N between burned and non-burned samples, whereas non-significant increases were found in burned soils for oxidizable carbon (C<sub>ox</sub>), total nitrogen (N<sub>tot</sub>) , Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup>, and soil hydrophobicity. The differences caused by the fire were no longer evident one year later. Furthermore, in one sampling site (Vitric Leptosols under low pine forest with a mixed heath/beech tree understory) a wide variation in the content of C<sub>ox</sub> and N<sub>tot</sub> and high water repellency was observed relative to the other sites. These differences can be attributed to the composition of the understory vegetation. Significant correlations between soil hydrophobicity with CE<sub>1:5</sub>, aggregate stability and the contents of C<sub>ox</sub>, N<sub>tot</sub>, NH<sub>4</sub><sup>+</sup>-N, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup> were found.

Influence of crop residues and nitrogen fertilizer on soil water repellency and soil hydrophobicity under long-term no-till

2019 ◽  
Vol 99 (3) ◽  
pp. 334-344 ◽  
Author(s):  
J.J. Miller ◽  
M.L. Owen ◽  
B.H. Ellert ◽  
X.M. Yang ◽  
C.F. Drury ◽  
...  
Keyword(s):  
Soil Water ◽  
Crop Residues ◽  
Water Repellency ◽  
N Fertilizer ◽  
Soil Water Repellency ◽  
Index Method ◽  
Organic C ◽  
No Till ◽  
Soil Hydrophobicity

Crop residues and N fertilizer under no-till may increase soil water repellency (SWR) and soil hydrophobicity, but few studies have examined these two treatment factors and their interaction. A laboratory study was conducted using a long-term (since 1999) field experiment on a clay loam soil to determine the effect of three crop residues and two N fertilizer levels on SWR and soil hydrophobicity under no-till within the Dark Brown soil zone of the semi-arid Canadian prairies. The three residue treatments were residues removed from soil (Rx0), residues returned to soil (Rx1), and residues supplemented to soil (Rx2). The two fertilizer N treatments were 0 (N0) and 45 kg N ha−1 (N1). Surface (0–10 cm) soil samples were taken in the spring of 2017 after 17 yr. Laboratory measurements were conducted on air-dried and sieved (<2 mm) soil to determine SWR using the repellency index method (RI), soil organic C, hydrophobic CH and hydrophilic CO functional groups, and soil hydrophobicity (CH/CO ratio). Mean RI values ranged from 2.19 to 2.75, indicating subcritical (RI > 1.95) SWR. Similar (P > 0.05) RI values were found for the three residue and two N fertilizer treatments, but the trend was for greater RI with increased residue addition (by 12%–26%) and N fertilizer (by 8%). Soil hydrophobicity was significantly greater by 47%–82% for straw returned or supplemented than straw removed treatments, and by 33% for fertilized than unfertilized treatments. Overall, greater residues and N fertilizer had no effect on SWR, but significantly increased soil hydrophobicity.

Heating effects on water repellency in Australian eucalypt forest soils and their value in estimating wildfire soil temperatures

2004 ◽  
Vol 13 (2) ◽  
pp. 157 ◽  
Author(s):  
Stefan H. Doerr ◽  
William H. Blake ◽  
Richard A. Shakesby ◽  
Frank Stagnitti ◽  
Saskia H. Vuurens ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Soil Water ◽  
Water Repellency ◽  
Water Repellent ◽  
Laboratory Studies ◽  
Soil Water Repellency ◽  
Eucalypt Forest ◽  
Heating Effects ◽  
Soil Temperatures ◽  
Eucalypt Forests

Wildfires can induce or enhance soil water repellency under a range of vegetation communities. According to mainly USA-based laboratory studies, repellency is eliminated at a maximum soil temperature (T) of 280–400°C. Knowledge of T reached during a wildfire is important in evaluating post-fire soil physical properties, fertility and seedbed status. T is, however, notoriously difficult to ascertain retrospectively and often based on indicative observations with a large potential error. Soils under fire-prone Australian eucalypt forests tend to be water repellent when dry or moderately moist even if long unburnt. This study aims to quantify the temperature of water repellency destruction for Australian topsoil material sampled under three sites with contrasting eucalypt cover (Eucalyptus sieberi, E. ovata and E. baxteri). Soil water repellency was present prior to heating in all samples, increased during heating, but was abruptly eliminated at a specific T between 260 and 340°C. Elimination temperature varied somewhat between samples, but was found to be dependent on heating duration, with longest duration resulting in lowest elimination temperature. Results suggest that post-fire water repellency may be used as an aid in hindcasting soil temperature reached during the passage of a fire within repellency-prone environments.

scholarly journals Flexible conformation in organic matter coatings: An hypothesis about soil water repellency

2000 ◽  
Vol 80 (1) ◽  
pp. 143-152 ◽  
Author(s):  
J. L. Roy ◽  
W. B. McGill
Keyword(s):  
Soil Water ◽  
Conformational Changes ◽  
Contaminated Soils ◽  
Water Repellency ◽  
Supporting Evidence ◽  
Soil Water Repellency ◽  
Nonpolar Solvents ◽  
Causative Agents ◽  
Subsequent Exposure ◽  
Induced Changes

Some soils develop severe water repellency several years or decades following oil contamination. We previously reported that soil water repellency is completely eliminated by extraction with amphiphilic solvents, but barely reduced by extraction with nonpolar solvents. We report here on solvent-induced reversible soil water repellency. Our results indicate that: (i) water repellency is completely eliminated following extraction with amphiphilic solvent, but partially restored following subsequent exposure to nonpolar, non-H-bonding solvent; (ii) extraction with nonpolar, non-H-bonding solvent generates water repellency in readily wettable control wettable soils, but not in pristine wettable soils, and (iii) repeated sequential extractions alternating between amphiphilic and nonpolar, non-H-bonding solvent increase extractable material and reduce the magnitude of solvent-induced soil water repellency with time.We attribute reversible soil water repellency to solvent-induced changes in the conformation of causative agents of soil water repellency. Recent literature reports on the structural flexibility of "insoluble" organic macromolecules are discussed for supporting evidence. We propose that exposure to nonpolar, non-H-bonding solvents induces stretching of surface-exposed, nonpolar moieties (i.e. alkyl chains), whereas exposure to polar, H-bonding solvents induces their coiling. These solvent-induced conformational changes are retained upon solvent removal. Our results indicate that the wettability of oil-contaminated soils depends on both the interfacial conformation and the fractional coverage of their surface-exposed nonpolar moieties. Key words: Soil water repellency, crude oil, hydrophobic soil, conformational flexibility, swelling, solvents

scholarly journals Certain Soil Surfactants Could Become a Source of Soil Water Repellency after Repeated Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2577
Author(s):  
Enzhan Song ◽  
Keith W. Goyne ◽  
Robert J. Kremer ◽  
Stephen H. Anderson ◽  
Xi Xiong
Keyword(s):  
Organic Carbon ◽  
Soil Water ◽  
Water Repellency ◽  
Soil Particle ◽  
Wetting Agent ◽  
Repeated Treatment ◽  
Repeated Application ◽  
Soil Water Repellency ◽  
Soil Hydrophobicity ◽  
Wetting Agents

Repeated application of soil surfactants, or wetting agents, is a common practice for alleviating soil water repellency associated with soil organic coatings. However, wetting agents are organic compounds that may also coat soil particle surfaces and reduce wettability. For this experiment, hydrophobic sands from the field and fresh, wettable sands were collected and treated with either a polyoxyalkylene polymer (PoAP) or alkyl block polymer (ABP) wetting agent, or water only treatments served as a control. Following repeated treatment application and sequential washings, dissolved and particulate organic carbon (OC) were detected in the leachates of both sand systems. The total amount of OC recovered in leachates was 88% or less than the OC introduced by the wetting agents, indicating sorption of wetting agent monomers to soil particle surfaces regardless of soil hydrophobicity status. While ABP treatment did not alter solid phase organic carbon (SOC) in the sands studied, PoAP application increased SOC by 16% and 45% which was visible in scanning electronic microscopy images, for hydrophobic and wettable sands, respectively. PoAP application also increased the hydrophobicity of both sands that were studied. In contrast, ABP treatment increased the wettability of hydrophobic sand. Our results provide strong evidence that certain wetting agents may increase soil hydrophobicity and exacerbate wettability challenges if used repeatedly over time.

A quick fix for modeling infiltration in water-repellent soils

2021 ◽  
Author(s):  
Ryan Stewart ◽  
Majdi R. Abou Najm ◽  
Simone Di Prima ◽  
Laurent Lassabatere
Keyword(s):  
Soil Water ◽  
Wide Spectrum ◽  
Correction Term ◽  
Water Repellency ◽  
Infiltration Rate ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Simple Method ◽  
Wide Range ◽  
Infiltration Models

&lt;p&gt;Water repellency occurs in soils under a wide spectrum of conditions. Soil water repellency can originate from the deposition of resinous materials and exudates from vegetation, vaporization and condensation of organic compounds during fires, or the presence of anthropogenic-derived chemicals like petroleum products, wastewater or other urban contaminants. Its effects on soils range from mild to severe, and it often leads to hydrophobic conditions that can significantly impact the infiltration response with effects extending to the watershed-scale. Those effects are often time-dependent, making it a challenge to simulate infiltration behaviors of water-repellent soils using standard infiltration models. Here, we introduce a single rate-constant parameter (&amp;#945;&lt;sub&gt;WR&lt;/sub&gt;) and propose a simple correction term (1-e&lt;sup&gt;-&amp;#945;WRt&lt;/sup&gt;) to modify models for infiltration rate. This term starts with a value of zero at the beginning of the infiltration experiment (t = 0) and asymptotically approaches 1 as time increases, thus simulating a decreasing effect of soil water repellency through time. The correction term can be added to any infiltration model (one- two- or three-dimensional) and will account for the water repellency effect. Results from 165 infiltration experiments from different ecosystems and wide range of water repellency effects validated the effectiveness of this simple method to characterize water repellency in infiltration models. Tested with the simple two-term infiltration equation developed by Philip, we obtained consistent and substantial error reductions, particularly for more repellent soils. Furthermore, results revealed that soils that were burned during a wildfire had smaller &amp;#945;&lt;sub&gt;WR&lt;/sub&gt;&amp;#160;values compared to unburned controls, thus indicating that the magnitude of &amp;#945;&lt;sub&gt;WR&lt;/sub&gt;&amp;#160;may have a physical basis.&lt;/p&gt;

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