Soil–air partitioning of volatile organic compounds into soils with high water content

2020 ◽  
Vol 17 (8) ◽  
pp. 545
Author(s):  
Jeonghyeon Ahn ◽  
Guiying Rao ◽  
Mustafa Mamun ◽  
Eric P. Vejerano

Environmental contextAssessing environmental and human health impacts of chemical spills relies on information about how chemicals move across multiple environments. We measured volatile contaminants in the air above soil saturated with water to provide estimates of air concentrations of selected chemicals released to soil from an oil refinery in Texas during Hurricane Harvey. Estimated concentrations were below recommended exposure limits, even in a worst-case scenario. AbstractThe emission of volatile organic compounds (VOCs) from soil into air is affected by soil moisture dynamics, soil temperature, solar irradiance and carbon availability. The high amount of water in soil can modify its properties, which changes how VOCs interact. We conducted a comprehensive measurement of the soil–air partition coefficient (KSA) of VOCs into water-saturated soil with both low and high water contents for polar, weakly polar and nonpolar VOCs into a mineral soil (S-clay) and soil containing a high amount of organic matter (S-om) under a water-saturated condition. Partitioning of non-polar substituted aromatics (1,2-dichlorobenzene and toluene) was sensitive to the organic matter content in water-saturated soil. 1,2-Dichlorobenzene and toluene had higher affinities to S-om than to S-clay at all investigated water contents because of their strong interaction with the organic matter in soil. KSA decreased with elevated water content only for non-polar substituted aromatic VOCs. Less hydrophobic VOCs (benzene and trichloroethylene) exhibited similar partitioning into both soils by sorbing onto the air-water interface and dissolving in soil water, while the organic matter did not affect partitioning. The weakly polar and polar VOCs (methyl tert-butyl ether and 1-butanol) showed similar partitioning into both soils by dissolving in soil water while sorption to the organic matter was significant only at high soil water contents. KSA of VOCs on soil with high organic matter content correlated strongly with psat and Koa, but not on mineral soil. Estimates of the air concentrations for a subset of VOCs released from one refinery during Hurricane Harvey in 2017 in Harris County, Texas were lower than the recommended exposure limits, even under a worst-case scenario.

2021 ◽  
Vol 17 (14) ◽  
Author(s):  
Bazoma Bayili ◽  
Richard Ouedraogo ◽  
Hassane Sidibe ◽  
Sylvain Ilboudo ◽  
Georges Anicet Ouedraogo

Pesticides residues are frequently found in the environment far from the original point of their application. Besides the desired effects of pest control, non-target organisms, soil and water are contaminated by the pesticides. This paper presents results on the impact of these xenobiotics used in cotton cultivation on River "Wolo" environment in Burkina Faso by using the Pesticide Impact Rating Index (PIRI) software package. The assessment was based on the assumption of three scenarios taking into account the organic matter content of the soil and the presence of a buffer zone. Pesticides properties and use data, and data on the physical environment, were also used. Considering the worst case (scenario 2), diuron, haloxyfop-R-methyl, glyphosate and nicosulfuron were the most mobile. Diuron was classified as the most toxic pesticide to Scenedesmus quadricauda. Toxicity to Daphnia magna was extremely high with chlorpyrifos ethyl, very high with betacyfluthrin, deltamethrin, lamda-cyalothrin and high with flubendiamide. For Oncorhynchus mykiss, it was beta-cyfluthrin, deltamethrin and lamdacyhalothrin that caused a very high risk and chlorpyrifos ethyl and indoxacarb a high risk. For all pesticides, the risks are reduced overall depending on the width of the buffer zone and the organic matter content of the soil. The use of a pesticide in a given location must take into account its ecotoxicological impact on the surrounding ecosystem. Tools such as PIRI, could be used for the selection of pesticides to be used. Also, environmental parameters such as buffer zone and organic matter content should be used by farmers to limit the mobility of pesticides to water.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3441
Author(s):  
Jingyu Ji ◽  
Junzeng Xu ◽  
Yixin Xiao ◽  
Yajun Luan

The accurate monitoring of soil water content during the growth of crops is of great importance to improve agricultural water use efficiency. The Campbell model is one of the most widely used models for monitoring soil moisture content from soil thermal conductivities in farmland, which always needs to be calibrated due to the lack of adequate original data and the limitation of measurement methods. To precisely predict the water content of complex soils using the Campbell model, this model was evaluated by investigating several factors, including soil texture, bulk density and organic matter. The comparison of the R2 and the reduced Chi-Sqr values, which were calculated by Origin, was conducted to calibrate the Campbell model calculated. In addition, combining factors of parameters, a new parameter named m related to soil texture and the organic matter was firstly introduced and the original fitting parameter, E, was improved to an expression related to clay fraction and the organic matter content in the improved model. The soil data collected from both the laboratory and the previous literature were used to assess the revised model. The results show that most of the R2 values of the improved model are >0.95, and the reduced Chi-Sqr values are <0.01, which presents a better matching performance compared to the original. It is concluded that the improved model provides more accurate monitoring of soil water content for water irrigation management.


1990 ◽  
Vol 20 (9) ◽  
pp. 1332-1342 ◽  
Author(s):  
I. K. Morrison

Two sites, both supporting old-growth Acersaccharum Marsh, dominated forest on rugged topography in central northern Ontario, were compared in terms of organic matter and N, P, K, Ca, Mg, S, Fe, Mn, Zn, and Cu content in the tree- and field-layer phytomass, the forest floor, and the mineral soil. One site was on a shallow, low-base, Precambrian-derived till, and the other was on a till of somewhat higher base status. Gross and net growth of the overstory tree layer were also determined. Total phytomass values for the two stands at the beginning of the study period were 245 000 and 210 000 kg•ha−1, respectively. Gross growth was largely offset by mortality in both stands, producing a rough equilibrium with regard to net increment. Growth before mortality was on the order of 2.4–2.5 m3•ha−1•year−1 in terms of gross total wood volume or 3700–3900 kg•ha−1•year−1 in terms of phytomass, and it was slightly greater in percent terms on the higher base site. In addition to that in the phytomass, organic matter in the forest floor and mineral soil to a depth of 1 m also contributed to the total organic matter content of 638 000–642 000 kg•ha−1 (equivalent to 34 8000–353 000 kg•ha−1 of C) on both sites and was distributed as follows: 29–34% in phytomass, 5% in the forest floor, and 61–66% in mineral soil. The order of abundance of elements in the phytomass was similar on both sites: Ca > N > K > Mg > S > Mn > P > Fe > Zn > Cu, with accumulation in the phytomass in rough proportion to occurrence in the soil. A more base-rich parent material would appear to be the origin of 1452 kg•ha−1 of Ca estimated to be in the phytomass and forest floor on the higher base soil, compared with 1250 kg•ha−1 in the phytomass and forest floor on the lower base soil.


Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 797 ◽  
Author(s):  
Sergio A. Belmonte ◽  
Luisella Celi ◽  
Silvia Stanchi ◽  
Daniel Said-Pullicino ◽  
Ermanno Zanini ◽  
...  

Vineyard soils are typically characterised by poor development, low organic matter content and steep slopes. Consequently, they have a limited capacity for conservation of organic matter that is weakly bound to the mineral soil phase. Under such conditions, establishment of permanent grass may improve soil quality conservation. The aim of this study was to evaluate the effects of permanent grass v. single autumn tillage on soil structure and organic matter dynamics in a hilly vineyard. During the periods 1994–1996 and 2010–2012, soil samples were collected three times per year, in different seasons. Aggregate stability analyses and organic matter fractionation were performed. The effects of grass cover on soil recovery capacity after tillage disturbance were slow to become apparent. Slight increases in aggregate resistance and organic matter contents were visible after 3 years, and the two plots (permanent grass/previously tilled) showed a large decrease of aggregate losses and increase of organic matter only after long-lasting permanent grass. However, even a single tillage produced an immediate decrease in aggregate resistance, while the organic matter content remained unaffected. Organic matter, however, showed marked seasonal dynamics, which involved not only recently added organic matter fractions but also the mineral-associated pool. Tillage altered organic matter dynamics by preventing the addition of new material into the mineral-associated organic fractions and limiting the stabilisation of aggregates.


1964 ◽  
Vol 44 (1) ◽  
pp. 137-144 ◽  
Author(s):  
R. L. Halstead

In laboratory incubation experiments liming with Ca(OH)2, CaCO3, or MgCO3 inhibited the phosphatase enzyme activity as measured by determination of phenol or phosphorus released from disodium phenyl phosphate. Chloride and sulphate salts of calcium and magnesium had no appreciable effect on the measured activity. Incubation for 9 months reduced the activity in a group of acid soils but not in a group of nearly neutral soils. Addition of phosphate prior to incubation had no effect on activity in either group.In buffer systems with the pH controlled over the range pH 2.0 to 11.0, activity in samples of an acid mineral soil increased gradually from pH 2.0 to a maximum at about pH 7.0, and then declined rapidly. The occurrence of peaks of optimum activity at pH 5.0 and 9.5 indicated the presence of both acid and alkaline phosphatases in an organic soil.Although there was no significant relationship between phosphatase activity and pH, clay content, nitrogen, and total carbon content of 10 mineral soils, there was a higher activity associated with higher organic matter content in three groups of soils with 3.2, 24.8, and 80.2% organic matter. Initial phosphatase activity of a group of mineral soils was not related to the degree of mineralization of organic soil phosphorus found to occur during an incubation period.


Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 573-578 ◽  
Author(s):  
David R. Shaw ◽  
Glen P. Murphy

Laboratory studies were conducted to evaluate flumetsulam adsorption and mobility in seven Mississippi soils of different organic matter content, pH, and texture. Adsorption isotherms were determined for all soils using a 1:1 (soil: water) technique. In six of seven soils, Freundlichnconstants were close to unity, suggesting a partitioning-like adsorption mechanism for flumetsulam. Mobility was examined using packed soil columns.14C-flumetsulam recoveries in leachate ranged from 1 to 70% and were influenced by both organic matter content and soil pH. However, the effects of organic matter content and soil pH were not independent. Consequently, clear relationships between flumetsulam mobility and either organic matter content or soil pH were not established across all soils. However, among soils of similar pH (7.5 ± 0.3), mobility decreased linearly (R2= 0.75) as organic matter content increased from 0.7 to 3.6%. Across soils with similar organic matter content (3.9 ± 0.3%), mobility increased linearly (R2= 0.98) as soil pH increased from 5.3 to 7.2. Net adsorption constants (Kd) provided a more accurate assessment of flumetsulam mobility across all soils thanKoc.


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