Soil, lead field measurements

Kinetics of chemical weathering are important to understand the rates of rock dissolution, sediment formation, and acid neutralization in the environment. In this chapter, there are three principal objectives (1) to describe the theoretical kinetics of chemical weathering for pure minerals, (2) to discuss the relative advantages and disadvantages of various experimental apparatus for measuring those kinetics in soils, and (3) to make comparisons between laboratory and field measurements of weathering rates and solute transport. A case study of laboratory and field measurements at Bear Brook Watershed, east of Orono, Maine, at Lead Mountain, will be used to illustrate the principles discussed in this chapter. 

SussELL A and Ashley K (2002) Field measurement of lead in workplace air and paint chip samples by ultrasonic extraction and portable anodic stripping voltammetry. J Environ Monit 4 156—161. SvENSSON BG, Sghutz a, Nilsson A and Skerfv-ING S (1992) Lead exposure in indoor firing ranges. Int Arch Occup Environ Health 64 219-221. Thornton 1, Davies DJA, Watt JM and Quinn MJ (1990) Lead exposure in young children from dust and soil in the United Kingdom. Environ Health Perspect 89 55-60. 

As mentioned before, soil is a physically, chemically, and biologically complex system. Factors that affect corrosion in soil, in addition to specific ions, are resistivity of soil, oxygen content, and acidity. Field measurements of soil resistivity are covered in ASTM G 57, Method for Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method, which is the most widely used test, and using the proper meter produces accurate and reproducible results. Conducting field measurements of soil pH is covered in ASTM G 51, Test Method for pH of SoU for Use in Corrosion Testing. The corrosion resistance of lead and its alloys depends mainly upon the presence of silicate, carbonate, and to a lesser extent sulfates, in contributing to the passive film formation. 

There are a variety of field and laboratory analytical methods for soil lead measurement, depending on the type of analysis and its purposes in a given evaluation. Bulk soil lead measurement refers to measurement of the total lead content of the soil sample. Chemical speciation and micromineralogical studies in the context of human lead exposure variability refer to amounts of specific chemical forms of lead and their geochemical states. These studies are sometimes done in tandem with relative bioavailability testings, i.e., amounts of lead being absorbed under in vivo or in vitro simulation of in vivo conditions (Casteel et al., 2006) with respect to Pb source attribution. Stable isotopic analysis studies deal with the quantitative stratification of lead s stable isotopic composition into the four main stable isotopes lead-204, lead-206, lead-207, and lead-208 (Gulson et al., 1995, 1997). 

Field measurement of bulk soil lead by XRF instruments will typically require confirmation analysis through some randomly selected subset of further testing by some reference technique in the laboratory A AS, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), or ICP-mass spectrometry (ICP-MS). Other methods are electrochemical in nature, such as ASV and differential pulse polarography. Many soil samples are processed and analyzed directly in the laboratory. 

It is also possible to make measurements in situ, for example portable gamma detection equipment can be used if the target radionuclides can be characterised by key-line gamma energy levels. Considerations of the specimen size leads to an important difference between in situ investigations of chemically contaminated land and radioactively contaminated land. It is possible to make field measurements in situ of the chemical concentration of metals in soil by using Portable X-Ray Fluorescence (PXRF) equipment. In PXRF, the specimen size is of the order of a few cubic millimetres. It is therefore much smaller than a typical specimen that would be extracted for laboratory analysis. ... 

Dinitroaniline herbicides have low soil mobility potential. Herbicide residues in the treated field are usually incorporated into the upper layers of the soil mainly as unextractable bound residue therefore, the movement of dinitroaniline herbicides from soil to the water compartment is minimal. Run-off is the principal route, which could lead to the contamination of surface waters. Residue methods were developed to measure the parent concentration in water samples. 

Pozzolanic S/S has many varied applications in the field. It has been found to be a fast, simple, and low-cost measure for the treatment of a variety of wastes. It has been used for treating solids, liquids, sediments, and sludges from several industries, particularly those that produce heavy-metal-contaminated waste streams, and especially at sites where the soil contains lead. 

In the field of toxic substances which pollute our environment, special importance must be attached to the heavy metal lead, which, until the late eighties arose primarily from automobile exhaust [EWERS and SCHLIPKOTER, 1984], For quantitative measurement of the impact of this lead, it is essential to establish the correlation between the lead content of the plants and soils, the traffic density, and the distance from the road. 

In medicine, researchers can measure lead levels in bone in vivo by taking the ratio of the Pb lines to the elastic scatter peak from the bone (as an internal standard). Levels of lead in the 3-30 ppm range have been measured. Trace elements in soil and sediment can be measured to collect geological, agricultural, and environmental data both in the lab and in the field, using portable XRF analyzers. 

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