aggeol 121

aggeol 121 - Chapter 1- The extent of global pollution...

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Chapter 1- The extent of global pollution Pollution - is ubiquitous and takes many forms and shapes. The accumulation and adverse affects of contaminants or pollutants on human health and welfare and/or the environment -can be solids, liquid or gases -poor waste management or disposal can lead to the presence of pathogenic microorganisms in water Xenobiotic waste -compounds that are foreign to natural ecosystems and that are less subject to degradation Lag period - low growth phase Exponential phase -number or organisms increases exponentially for a finite period of time Stationary phase -which the total number of organisms remains constant as new organisms are contantly being produced while other organisms are dying Death phase -total number of organisms deceases Two mechanisms prevent the number of organisms from increasing ad infinitum: 1. Organisms begin to run out of nutrients 2. Waste products build up within the growth medium and become toxic to the organisms CAFO -concentrated animal feedlot operations, where a large number of animals are kept in close proximity, require special attention to minimize the potential pollution Urbanized areas consume more natural resources and produce more waste per capita than rural areas. Augers -useful in that they allow samples to be taken at exactly the same depth on every occasion. Water at a given site tends to be more homogeneous that soils, with less site to site variability between two samples collected within the same vicinity. Bioaerosols -aerosolized biological particles including microorganisms Impingement device -trapping of airborne particles in a liquid matrix Impaction Device -forced deposition of airborne particles on a solid surface Two of the most commonly used devices for microbial air sampling: 1. SKC biosamplers 2. Andersen Six Stage Impaction Sampler Atomic Absorbtion- gave measurements at the level of milligrams per liter Flameless AA -using a graphite furnace improved detection limits to the level of micrograms per liter Inductively Coupled Plasma (ICP )-which has detection limits of nanograms per liter Such advances like synchrotron x-ray micro tomography, have allowed us to begin to directly measure the pore scale distribution of fluids in porous media. -this will provide a better understanding of how water and organic liquids move through subsurface The use of molecular technology in particular has revolutionized biological detection capabilities Polymerase Chain Reaction -allows for detection of an organisms DNA at a nanogram level. Sequence analysis using PCR and computer searches allows for enhanced identification of new microbes Risk assessment -integral part of pollution science. Its importance lies in the fact that it provides a quantifiable answer to the question “is this polluted site safe?” It consists of four basic steps:
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1. Hazard Identification -defining the hazard and nature of the harm; identifying a chemical contaminant such as lead or carbon tetrachloride, and documenting its toxic
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This note was uploaded on 02/22/2012 for the course AG 2373 taught by Professor Staff during the Fall '10 term at Texas State.

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aggeol 121 - Chapter 1- The extent of global pollution...

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