Contamination in environment

Haag, W.R. and Yao, C.C.D., Rate constants for reaction of hydroxyl radicals with several drinking water contaminants, in Environ. Sci. Technol., 26(5), 1005-1013, 1992. 

Pyoungtak City, 2003. Investigation on Residents health and PCDDs/DFs contamination in environments near a waste incinerator, KeumHo Environment Incoporation. Research report (in Korean), Pyoungtak, Korea. 

These systems have been operated in extremely low quality (and radioactivity contaminated) industrial environments for the past several years without any major equipment or component failures. Utilizing specialized operating/warm-up procedures, they have operated in low grade, out-of-doors, dust ridden, rain-soaked, industrial environments at temperature ranges which greatly exceed the original equipment manufacturers (OEM) specified limits. The systems have been successfully operated at ambient temperatures of minus 10 to plus 103 degrees Fahrenheit without any pre-mature or un-anticipated equipment failures. 

Three approaches have been identified that reduce susceptibility of CA resists to airborne contamination. In the first, process engineering changes such as the addition of special activated carbon filters to the environmental chambers surrounding the exposure tools (76,79), overcoating the resist with a soluble protective film to isolate the resist from the environment (77,80,81), or modifications of the process flow to minimize the time interval between exposure and post-exposure bake have been shown to improve CA resist processibibty. 

Control of metalloid content in natural objects, foodstuff and pharmaceuticals is an important task for modern analytical chemistry. Determination of elements such as Arsenic is necessary for evaluation of object toxicity, since their content in environment may exceed MCL (maximum contaminant level), posing hazard to human health. Elements such as Selenium in definite doses are healthy, but in greater quantities they produce toxic effect. 

A characteristic of the air contamination in most occupational environments is that there is most always a continual change in concentration with respect to time and... 

The solids that result from wastewater treatment may contain concentrated levels of contaminants that were originally contained in the wastewater. A great deal of concern must be directed to the proper disposal of these solids to protect environmental considerations. Failure to do this may result in a mere shifting of the original pollutants in the waste stream to the fmal disposal site where they may again become free to contaminate the environment and possibly place the public at risk. A more reasonable approach to ultimate solids disposal is to view the sludge... 

The target level procedure was applied to 16 common air contaminants (Table 6.19). These are common contaminants in the industrial environment, and in many cases are the most critical compounds from the viewpoint of need for control measures. The prevailing concentration data as well as the benchmark levels were taken from Nordic databases, mainly the Finnish sources, and described elsewhere.In addition, a general model for assessing target values for other contaminants is presented in the table. 

The purpose of open unidirectional airflow benches is to protect products from particulate contaminants by creating a controlled environment. These benches are used, for example, in electronic, biological, pharmaceutical, and food industries. It should be mentioned that within pharmaceutical production, aseptic sterile processes must be carried out in a Class 100 environment (U.S. Federal Standard 209 E, Airborne Particulate Cleanliness Classes in Cleanrooms and Clean Zones). To avoid particle contamination in the bench, horizontal or vertical airflow with high-efficiency particulate air (HEPA)-filtered air is used. The air velocity is normally 0.4-0.5 ra s". Some examples of typical arrangements of open unidirectional airflow benches are shown in Fig. 10.51. 

Stainless steels are used in a wide variety of applications and are most often selected because steel or cast iron would corrode at an unacceptably high rate or produce high levels of iron contamination in the proposed service environment. The main limitations on their uses are ... 

Polychloroprene and acrylonitrile-butadiene rubber compounds have satisfactory chemical resistance but, except for phosphoric acid, are not suitable for mineral acids at higher concentrations. However, they have good resistance to oils, acrylonitrile-butadiene rubber being the better, and so are often used in oil-contaminated aqueous environments. Generally, abrasion resistance is only fair. Normal maximum working temperature is about 100°C. Acrylonitrile-butadiene rubber ebonites are sometimes used especially where solvent contamination occurs, but are normally very brittle and so should be used with care. 

As reviewed designers in the plastics and other industry have the responsibility to ensure that all products produced will be safe and not contaminate the environment, etc. Recognize that when you encounter a potential problem, you are guilty until proven innocent (or is it supposed to be the reverse). So keep the records you need to survive the legal actions that can develop. 

Kolpin DW, Furlong ET, Meyer MT, Thurman EM, Zaugg SD, Barber LB, Buxton HT (2002) Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000 a national reconnaissance. Environ Sci Technol 36 1202-1211... 

Terzic S, Senta I, Ahel M, Gros M, Petrovic M, Barcelo D, Muller J, Knepper T, Marti I, Ventura F, Jovancic P, Jabucar D (2008) Occurrence and fate of emerging wastewater contaminants in Western Balkan Region. Sci Total Environ 399 66-77... 

Ceron JJ, Panizo CG, Montes A. 1995. Toxicological effects in rabbits induced by endosulfan, lindane, and methyl parathion representing agricultural byproducts contamination. Bull Environ Contam Toxicol 54 258-265. 

Coullard CM, Nellis P. 1999. Organochlorine contaminants in mummichog (flindulus heteroclitus) living downstream form a bleache-kraft pulp mill in the Miramichi estuary. New Brunswick, Canada. Environ Toxicol Chem 18(ll) 2545-2556. 

McConnell R, Pacheco F, Wahlberg K, et al. 1999. Subclinical health effects of environmental pesticide contamination in a developing country Cholinesterase depression in children. Environ Res A81 87-91. 

De Vault DS. 1985. Contaminants in fish from Great Lakes harbors and tributary mouths. Arch Environ Contam Toxicol 14 587-594. 

International Atomic Energy Agency (1972). Mercury Contamination in Man and His Environment, Technical Report Series 137—Contains some useful accounts of work done in Sweden on ecotoxicology of organomercury compounds that is difficult to find in the general literature. 

The main danger in the operation of a nuclear power plant is potential loss of control over the nuclear reaction. If the core overheats, it may either explode or melt down. In either event, radioactive materials escape Irom the reactor to contaminate the environment. Designers attempt to make nuclear reactors fail-safe by providing mechanisms that automatically shut the core down on overheating. One way this has been done is to design the control rods to fall into the core if their control mechanism fails. 

Surprisingly little is known about the resistance of yeasts, fungi and fungal spores to disinfeetants and preservatives. They are a major source of potential contamination in pharmaceutical product preparation and aseptic processing since they abound in the environment. It is, however, possible to make some general observations ... 

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