Soil binding

The percent pesticide volatilized in one day from wet soil correlated positively with the factor [vapor pressure/(water solubility X binding constant)]. This factor has been reported to be linearly related to the volatilization rate of chemicals from soil surfaces (27). For pesticides with Henry s law constants and soil binding constants within the range studied, the factor is also approximately proportional to the fraction of chemical in soil air at equilibrium (28). In the present study, it was found that four of the pesticides had low factors, and less than 1% volatilized in 1 day (Table III). Diazinon, on the other hand, had a higher factor, and 2% of it volatilized. The use of this factor therefore does seem to have some merit for qualitative prediction. 

The major factors affecting the fate and transport of TNT in soils are transformation, sorption, and irreversible soil binding and immobilization. TNT, RDX and HMX transformations are significantly enhanced under anaerobic conditions. The addition of Fe ions to soils is considered as the resource of transport and fate of NACs explosives where TNT transformation in soils can occur both biologically and abiotically. The transformation of TNT in soils is significantly dependent on pH in the presence of Fe ions. 

Some animals, such as monkeys, parrots, or geese, ingest soil. For geese (185) it was shown that the ingested soil binds dietary allelochemicals, especially alkaloids (185). This procedure would reduce the allelo-chemical content available for resorption. 

Lindane has been shown to have a low soil binding affinity. Therefore, it may be mobile in soils with especially low organic matter content or subject to high rainfall and pose a risk of groundwater contamination. Lindane is highly persistent in most soils, with a field half-life of 15 months. 

Pendimethalin is moderately persistent, with a field half-life of 40 days. It does not undergo rapid microbial degradation. Pendimethalin is strongly adsorbed by most soils. Increasing soil organic matter and clay is associated with increased soil binding capacity. 

BIOLOGICAL PROPERTIES conversion to dieldrin 80% after 8 weeks in river water kept in a sealed jar under sunlight and fluorescent light, initial concentration was 10 pg/L 75-100% disappearance from soils in 1-6 yrs half-life in water 25°C and 1 m depth 185 hr aerobic half-life 3 weeks-1.6 yrs anaerobic half-life 1-7 days ground water half-life 1 day-3.2 yrs surface water half-life 3 weeks-1.6 yrs soil half-life 20-100 days moderately persistent in soil bind tightly to soil and slowly evaporate to the air can be detected in water by EPA Method 608 gas chromatography, or Method 625 gas chromatography plus mass spectrometry... 

Chemicals may attach to soil, vegetation, or other surfaces once they are in the environment. Some portions of chemicals are not recovered by conventional extraction procedures because these bound or unextractable chemical residues are tightly bound to the soil or other sohd particles. It is very difficult to differentiate between bound residues of a parent compound and its transformation products. Concerns about bound pesticide residues in soil have been investigated since the late 1960s [33]. The exact mechanism of soil-binding and the ultimate fate of bound residues and their biological significance are not well understood for most chemicals. 

The phytotoxicity of glyphosate in soil is very low and may be due either to rapid degradation to aminomethylphosphonic acid or to a high degree of soil binding [41]. 

Lead-acid batteries, after consumer use, do not typically release aU of their lead contents into environmental dispersion channels. Instead, the lead content of much lead-acid battery production is recycled. This is not to say that the cmder forms of battery recycling are or have not been associated with waste streams, particularly at the breaking phase where lead components are first recovered for eventual secondary smelting. Unsecured disposal on land of battery acid containing lead provides not only plumes of the metal in toxic bioavailable forms but also mobility for it as the acid retards soil binding of lead. That recycling, often classified as part of scrap lead inventories, is a significant contributor to secondary lead production. As seen in various tables in Chapter 3, secondary lead production over recent decades has become a major part of total production. 

The polymers are effective through two mechanisms, soil binding and flocculation. The polymer can bind to soil crumbs, giving structural stability. This reduces crumb breakdown on irrigation and maintains an open structure, which facilitates infiltration. This mechanism... 

Lastly, in combination, these compounds compete for soil binding sites quite differently, each changing the availability to plants of the others [151]. 

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