Soil exposure

Hydrogen selenide in a concentration of 1.5 ppm is intolerable to man. Selenium occurs in some solid in amounts sufficient to produce serious effects on animals feeding on plants, such as locoweed, grown in such soils. Exposure to selenium compounds (as Se) in air should not exceed 0.2 mg/m3 (8-hour time-weighted average - 40-hour week). 

Simcox NJ, Fenske RA, Wolz SA, et al. 1995. Pesticides in household dust and soil Exposure pathways for children of agricultural families. Environ Health Perspect 103 1126-1134. 

Role of Humidity in Soil Exposure Pathway Formation in Steppe and Desert Ecosystems... 

The content of heavy metals in Steppe soils is tightly connected with their contents in geological rocks. In formation of soil exposure pathways in Desert ecosystems, water-soluble forms of these metals play the most important role. We can see an analogy between the increasing content of elements in soil dead organic matter as a function of decreasing water excess in Forest ecosystems and the increasing content of water-soluble species of chemical elements in the soils of Dry Steppe and Desert ecosystems as a function of enhanced aridity. The accumulation of water-soluble species occurs in the upper horizon for almost all elements, with exception of strontium. The main factor responsible for the accumulation of water-soluble forms is connected with evapotranspiration. 

Near a hazardous waste site, heptachlor and heptachlor epoxide can enter your body if you breathe contaminated air, drink contaminated water, or touch contaminated soil. Exposure around hazardous waste sites can also occur by eating plants or animals that have been contaminated with heptachlor or heptachlor epoxide. Sometimes small children eat soil. If the soil is contaminated with heptachlor or heptachlor epoxide, they will be exposed in this way. Heptachlor epoxide can enter an infant s body in mother s milk after the mother has been exposed to heptachlor or heptachlor epoxide. Heptachlor can enter the bodies of people who make it in factories if they breathe it in or get it on their skin. 

Children might be exposed to 3,3 -dichlorobenzidine if they eat small amounts of soil contaminated with 3,3 -dichlorobenzidine. However, studies suggest that it is very difficult to release 3,3 -dichlorobenzidine once it becomes attached to soil. Exposure via contaminated soil may occur if they live in an area near a source of the chemical (such as a hazardous waste site that contains 3,3 -dichlorobenzidine). Children can also be exposed if the parents work at chemical facilities where 3,3 -dichlorobenzidine is handled and bring home contaminated clothing or tools or if they do not shower before coming home. There are no known unique exposure pathways for children. 

It should be noted that a source in one medium may lead to additional intake from other routes, e.g., for drinking water, dermal and inhalation exposure may occur during a shower, and for soil, exposure would often be both via ingestion and dermal contact when possible, such intake should also be considered in the derivation of guidance values. 

In the field, parathion is converted to varying degrees to paraoxon, which may persist on foliage and in soil. Exposure to paraoxon from weathered parathion residues by the dermal route on reentry by field-workers has resulted in anticholinesterase poisonings. ... 

Earthworms, three species 40-238 mg/kg soil exposure duration unknown Earthworm, Eisenia andrei juveniles exposure for 12 weeks 18 mg/kg DW soil 56 mg/kg DW soil 100 mg/kg DW soil... 

The HRS system is based on risk to health and the environment. The criteria examined include the groundwater migration pathway, surface water migration pathway, soil exposure pathway, and air migration pathway (Hen-drichs, 1991). The ranking attempts to quantify the risk each site poses on a relative scale. Only those sites placed on the NPL will receive CERCLA funds however, regulations in the CERCLA can still be applied to non-NPL sites. 

If the soil is not conducive to sampling with airtight coring devices or cut-off syringes and low VOC concentrations are a matter of concern, we may revise the procedures and collect the needed 5 g of soil with a spatula followed by placing it into a vial. The key is to do it fast in order to minimize the soil exposure to air. 

THERdbASE contains two major modules, namely a Database Module and a Model Base Module. The Database Module relates information from exposure, dose and risk-related data files, and contains information about the following population distributions, location/activity patterns, food-consumption patterns, agent properties, agent sources (use patterns), environmental agent concentrations, food contamination, physiological parameters, risk parameters and miscellaneous data files. The Model Base Module provides access to exposure dose and risk-related models. The specific models included with the software are as follows Model 101, subsetting activity pattern data Model 102, location patterns (simulated) Model 103, source (time application) Model 104, source (instantaneous application) Model 105, indoor air (two zones) Model 106, indoor air (n zones) Model 107, inhalation exposure (BEAM) Model 108, inhalation exposure (multiple chemicals) Model 109, dermal dose (film thickness) Model 110, dose scenario (inhalation/dermal) Model 201, soil exposure (dose assessment). 

Choose an area that is uniform in terms of vegetation, soil, exposure, and disturbances such as human or pet traffic. Trap in one homogeneous wooded area and another open one such as a clearing in the woods. Each test area should be at least 30 X 30 m large. 

Benchmark Screening Concentration Corresponding to lO" Individual Cancer Risk tor Inhalation Exposure, Oral Exposure, Food Chain Soil Exposure... 

Cancer, or neoplasia, which occurs in one of every four individuals and results in the death of one of every five individuals in the United States, is a complex disease with multiple causes. Many intrinsic and extrinsic factors influence the development of cancer. Intrinsic or host factors include age, sex, genetic constitution, immune system function, metabolism, hormone levels, and nutritional status. Extrinsic factors include substances eaten, drunk, or smoked workplace and environmental (air, water, and soil) exposures natural and medical radiation exposure ... 

Cancer risk assessment for exposure to chemicals in soil involves several unique exposure issues. Volatile chemicals in soil may evaporate off soil particles and thus may result in a potential inhalation hazard, but little or no hazard from dermal or oral exposure. Semi-volatile and nonvolatile chemicals may bind tightly to soil, and thus be less available for absorption. Unlike air, water, and food, soil is not directly consumed (in most cases), but is contacted incidentally while carrying out other activities. Thus exposure scenarios and soil exposure factors are more variable and important for chemicals in soil than in other media. The EPA Exposure Factors Handbook (EPA 1997a) has summarized these principles especially relevant in the handbook are Chapter 4 on soil ingestion. Chapter 6 on dermal exposures, and Chapter 17 on residential exposures. Recently, this has been supplemented with child-specihc exposure guidance (EPA 2008b). 

Characterisation of exposure. This process intends to estimate how much of a harmful chemical substance is for how long in contact with a specified organism. Exposure characterisation is usually a complex process that should consider physico-chemical properties of pollutants and the site (e.g. to estimate influencing factors such as the availability of contaminants), as well as naturally occurring pollutant degradation. For contaminated soils, exposure is usually estimated with measurement of toxicant concentrations by chemical analysis... 

The degree to which carbamothioate herbicides cause microbial adaptation depends on specific herbicide structure (lj), 21 22). Vernolate and EPTC have similar structures and soil exposure to either herbicide fully affected the degradation of the other. 

Butylate has a structure somewhat different than vernolate and EPTC and its degradation pattern was only moderately affected by prior use of EPTC and vernolate. Cycloate has a cyclohexane moiety that makes it unique from butylate, EPTC, and vernolate. The degradation rate of cycloate was not influenced by previous soil exposure to either EPTC, vernolate, or butylate (22), nor has prior cycloate treatment increased the degradation rate of the latter carbamothioates (19,... 

Table VII. Effects of previous soil exposure to butylate or vernolate on the populations of butylate- or...

Johnson MS et al., Toxicological responses of red-backed salamanders Plethodon cinereus) to subchronic soil exposures of 2,4-dinitrotoluene. Environ. Pollut. 147, 604, 2007. 

Johnson MS et al., Toxicologic and histologic response of the terrestrial salamander Plethodon cinereus to soil exposures of l,3,5-trinitrohexahydro-l,3,5-triazine, Arch. Environ. Contam. Toxicol., 47, 496, 2004. 

Affected Soils Exposure pathways and associated screening limits designated under applicable rules. Review applicable environmental regulations. 

The first step of the exposure assessment is to quantify the amount of chemical received as a dose following exposure to contaminated site soils. Exposure must... 

A method of protecting personnel from sidewall cave-in by forming sides of an excavation that are inclined away from the excavation. The safe angle of slope required varies with different types of soil, exposure to the elements, and snperimposed loads. Slow-Moving Vehicle Emblem... 

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