Secondary Contaminants

The U.S. Environmental Protection Agency, under the Safe Drinking Water Act, set the secondary contaminant level for silver ia drinking water at 0.1 mg/L (20). Secondary contaminants are not considered to be hazardous to health and thus the limits are not federally enforceable. 

The analytical procedure is checked by analyses of method blanlcs to assure that secondary contamination by the analytes to be determined is avoided or minimized. Because the water content of the CRM matrix to be analyzed may vary from one laboratory to another (dependent on the local humidity and temperature), the water content has to be determined. Accordingly, at least three independent samples are kept at I05°C for 2 h, then allowed to cool to ambient temperature in a desiccator and the water loss is determined. The certified values are generally reported on a dry mass basis. 

Assessing secondary contamination in creating U-series disequilibria... 

Cl and Ba consistently argue that the U-series disequilibria in MORB do not reflect secondary contamination. One important check that all U-series studies of MORB routinely perform is analysis of ( " U)/( U). Since of seawater is well... 

Consumption/intake of a secondary contaminant, for example, by eating contaminated crops or livestocks fed in the contaminated area... 

About one third of the overall production was applied in buildings used as additives to dyes and joint sealers. Normally, the use of PCBs in the materials is not (more) known to the inhabitants or users of the houses. Only in the case of secondary contamination of ambient air or food detected by chance or by systematic search, those buildings were decontaminated. Spreading of PCBs into the environment was accelerated by mixing of used hydraulic or heat exchanger fluids... 

Interaction of POCs with oil products and synthetic surfactants in water <- Factors increasing the ecological risk of contamination of river waters entering into the Caspian Sea by POCs Secondary contamination of river waters by POCs from bottom sediments... 

In the Rybinsk reservoir constructed in the upper Volga (Yaroslavl, Vologda and Tver regions), the ratio of PCBs in water and silts, in some places, was less than 1, which would suggest probable secondary contamination of water (Figure 7, Table 4)... 

Rates of POCs secondary contamination of fresh and salt waters from bottom sediments ... 

Regarding isolation and decontamination, Standard Precautions are recommended for healthcare personnel. Person-to-person transmission is rare. Victims exposed to Q fever by aerosol do not present a risk for secondary contamination or re-aerosolization of the organism. Decontamination can be done with soap and water, or a 0.5 percent chlorine solution on personnel. 

Hospital staff working in an enclosed area can be secondarily contaminated by cyanide vapor off-gassing from heavily soaked clothing or skin, or from toxic vomit. Avoid dermal contact with cyanide-contaminated victims or with gastric contents of persons who may have ingested cyanide-containing materials (patients do not usually pose secondary contamination risks after contaminated clothing is removed and the skin is washed. 

Secondary Contamination Contamination that occurs due to contact with a contaminated person or object rather than direct contact with agent aerosols cross contamination. 

The degree of contamination governs the performance and product quality and affects the utility value of the end product. Secondary contaminants such as additive agglomerates are included in the term contamination . Particularly in case of film polymers, such particles diminish the quality of audio or video tapes due to the vulnerability of films to this drop-out phenomenon. 

There are many variables associated with estimating the cost of perchlorate contamination. For many commercially available systems, cost data is estimated based on pilot- or bench-scale tests. These estimates may not include secondary contaminant disposal costs or other costs of operation. Costs are also likely to vary considerably based on site-specific conditions such as contaminant concentrations, additional contamination, treatment volumes, and treatment rates. 

Membranes are semipermeable barriers that permit the separation of two compartments of different composition or even condition, with the transport of components from one compartment to another being controlled by the membrane barrier. Ideally, this barrier is designed to let pass selectively only certain target compounds, while retaining all others—hence the denotation semipermeable . Membrane separations are particularly suitable for food applications because (1) they do not require any extraction aids such as solvents, which avoids secondary contamination and, hence, the necessity for subsequent purification (2) transfer of components from one matrix to another is possible without direct contact and the risk of cross-contamination (3) membrane processes can, in general, be operated under smooth conditions and therefore maintaining in principle the properties and quality of delicate foodstuff. 

Saturated Hydraulic Conductivity, 393 Diffuse double layer, 367-369 Na-Ioad, 379, 410-416 ESP 379, 410-416 SAR, 197, 412 Dispersion, 414 Swelling, 103-115 Osmotic pressure, 377 Secondary Contaminants, 478, 479 Copper, 479, 488 Iron, 479, 488 Zinc, 479, 488 Foaming Agents, 488 Chloride, 488 Color, 489 Corrosivity, 489 Hardness, 489 Manganese, 489 Odor, 490 pH, 490 Sodium, 490 Sulfate, 490 Taste, 490... 

The disposal of low-level radioactive waste generated by the U.S. Department of Energy (DOE) during the Cold War era has historically involved shallow land burial in unconfined pits and trenches. The lack of physical or chemical barriers to impede waste migration has resulted in the formation of secondary contaminant sources where... 

The results of the multiple nonreactive tracer study showed that secondary contaminant sources may form within the bedrock matrix, and that the importance of this source increases with continued contaminant discharge through the bedrock fracture network. This may be particularly important for reactive contaminants such as radionuclides, where matrix diffusion can enhance solute retardation by many orders of magnitude. 

A rapid decision must be made to protect the hospital from secondary contamination. Storage of appropriate inventories of chemical antidotes, or guick access to such stores, is critical to the successful treatment of many chemical weapon victims. 

Protect the emergency department from secondary contamination. 

Horton, D.K., Burgess, P., Rossiter, S., Kaye, W. (2005). Secondary contamination of emergency department personnel from o-chlorobenzylidene malononitrile exposure, 2002. Ann. Emerg. Med. 45 655-8. 

Chlorine does not leave an environmental residue, so animals may be returned to affected pastures within hours to days (more quickly in warm environments) (Munro et al, 1999). When entering the area contaminated with chlorine gas, rescuers should wear self-contained breathing apparatus (SCBA) and protective clothing (gloves, gowns, masks) until the gas dissipates. The risk for secondary contamination of rescuers is low. Chlorine gas does not bind to leather or fabrics. 

Phosgene is nonpersistent in the envhonment. Moisture reduces air concentrations (Borak and Diller, 2001). The potential for secondary contamination of rescue personnel is low, but rescuers should wear proper protective clothing. Phosgene gas does not persist in fabric or leather. 

Rescue personnel must wear protective clothing, eye protection, and a respirator as the potential for secondary contamination is high (HSDB, 2008). Mustard gas will penetrate wood, leather, rubber, and paints. 

Lewisite remains in the environment for about 24 h and it can react with water to form a solid arsenoxide that also has vesicant properties. Affected areas can be treated with strong alkalis to form less harmful substances. Rescue personnel need to wear protective clothing and masks as the risk for secondary contamination is high. Carcasses should be disposed of properly, either buried deeply (away from... 

Phosgene oxime is nonpersistent in the environment and it hydrolyzes rapidly in aqueous alkaline solutions. Veterinary personnel and rescuers should wear aprons, mbber gloves, and masks when treating patients to avoid secondary contamination. 

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