Contaminant Directive

BEOs consisting of open tube or duct ends can be connected directly to a source. In principle, these could be called closed systems, since their main function is to exhaust contaminants directly from the source, which is enclosed in the duct. However, they are usually regarded as basic exhausts since they function as such when not connected to the source. 

Booths are partially enclosed workplaces with one or more open facefs) for access by workers. These openings at one or more sides of the enclosure function not only to capture air contaminants directly through their short-distance capture capability but also to cause an airflow in a certain direction (normally away from the worker/work process and into the enclosure). The capture efficiency could be increased by using an existing main flow direction (e.g., thermal flows caused by heat sources) to support the capture process. 

Local extract is used to remove contaminants directly from a process to the exterior without passing through personnel breathing zones. It thus provides a high degree of safety and because small volumes of air are extracted relative to a dilution ventilation system it is energy efficient. 

Low concentrations of proteins found in ES products are further complicated by high concentrations of salts. Salt contamination directly interferes with the electrophoresis process. The movement of salt through the first dimension to the extremities of the pH gradient will prolong the time needed to separate... 

Hauser, B., P. Popp, and E. Kleine-Benne (2002). Membrane-assisted solvent extraction of triazines and other semi-volatile contaminants directly coupled to large-volume injection-gas chromatography-mass spectrometric detection. J. Chromatogr. A, 963 27-36. 

This chapter deals with the derivation of aquatic environmental quality standards (EQSs), including standards for the protection of water dwellers, predators of water dwellers, and human water users. However, the main focus is on standards for the protection of organisms that live in water or aquatic sediment and are able to absorb contaminants directly via their gills, skin, and/or cell surfaces. In other words, the chapter primarily covers the derivation of standards for the protection of aquatic ecosystems. 

The mode of fluid flow in the aerated zone may be changed by the hydraulic aspects of fluid waste disposal. Constant release of large amounts of fluids may cause a local rise in the hydraulic head. Coupled with chemical fluid-rock interactions, this may form new high-conducting conduits that can lead the contaminants directly into the saturated zone. In other cases, fine particles that come with the contaminating fluids can clog pores in the aerated zone and reduce through-flow. 

Agent Contaminant Direct Measurement (Extraction)0 (ppb) VSL (Vapor Screening Level)6 Process Decontamination History0... 

Direct Removal Using SCCO2- This is the least expensive option. This system uses liquid carbon dioxide or supercritical carbon dioxide to remove contaminants directly from the parts or to remove residual solvent from a separate, non-carbon-dioxide cleaning process. 

Ozone gas can oxidize contaminants directly or through the formation of hydroxyl radicals. Like peroxide, ozone reactions are most effective in systems with acidic pH. The oxidation reaction proceeds with extremely fast, pseudo-first-order kinetics. Owing to ozone s... 

A local exhaust is generally preferred over a dilution ventilation system for health hazard control because a local exhaust system removes the contaminants directly fi om the source, whereas dilution ventilation merely mixes the contaminant with uncontaminated air to reduce the contaminant concentration. Dilution ventilation may be acceptable when the contaminant concentration has a low toxicity or a threshold limit value (TLV) > 100 ppm, and the rate of contaminant emission is constant and low enough that the quantity of required dilution air is not prohibitively large. However, dilution ventilation generally is not acceptable when the TLV is less than 100 ppm. 

Note Data compilations that do not include He and Ne concentrations have been excluded as it is not possible to assess atmospheric contamination. Direct samples of volcanic gases have been excluded... 

Besides, the pesticide runoff is the main process that can contaminate the surface watet It occurs if the rainfall events prevail on the soil absorpdon. The acdve surface soil depth that interacts with runoff is about 2-10 mm. Surface water also can be contaminated directly by pesdcides by the ddft caused by pesticide application. 

Consistently, the floral samples contained the lowest levels of all contaminants. The levels were all significantly lower than those observed in either the lagoon or the bees. These results are to be expected because the majority of plants in the study site were not taking up the contaminants directly from the lagoon water and therefore, the redistribution of contaminants to the plants in the area was somewhat limited. 

Currently, the Lasagna process is a commercially viable soil remediation process that has been proven especially effective in treating chlorinated solvent contamination in low-permeabiUty soils. The use of DC electrical current to heat the soil and to mobilize pore water and contaminants directionally into degradative treatment zones makes in situ remediation possible. The process is a truly treatment in-place method since no contamination is brought aboveground. Transport and destruction take place within the soil mass. 

Analytical measurements can be direct, i.e., the water samples are measured directly by the instrumentation, for example, UVF and immunoassay techniques can measure oil contamination directly in water samples. However, most methods measure the contaminated sample indirectly and therefore require sample treatment. The methods employed in sample treatment are common to all the indirect measurements. 

The damage caused by the atmospheric dispersion of radioactive material may be the result of ln<]iury of people or the contamination of property. The Injury type of damage may be further categorized as those Injuries which result from direct exposure to the cloud of contaminants (direct effects) and those which result from material deposited on the ground (Indirect or residual effects). 

One issue that has demanded considerable attention over recent years has been the contribution of vehicle-generated lead aerosol to human uptake of lead and hence blood lead levels. There are three principal pathways of human exposure to this source of lead direct inhalation, ingestion of deposited dust (street dust, household dust, soil) and ingestion of foods contaminated directly or indirectly by deposited lead. 

Gas chromatography, coupled with flame-ionisation, electron capture (for halogenated species) and mass spectrometric detectors, is the most popular tool for determination of SVOCs in melted snow samples [44]. A prerequisite is the efficient separation of the analytes from the aqueous matrix, which can be accomplished using filtration onto quartz fibre filters and sohd phase extraction [88]. Solid phase micro-extraction, which utilises equihbrium-based adsorption of analytes onto a polymer fibre bundle, has also been proposed and tested in laboratory studies [13, 89]. Both methods allow for an efficient transfer into the injection port of a gas chromatograph without water contamination. Directly coupled inlet sampler with GC-EID instrumentation has also been used [90]. The air sample was pre-concentrated using adsorbents (Carbotrap B, Carbosieve), followed by heating and collection on a cryofocuser (a fused silica capillary tube packed with... 

All the sampling systems that are mentioned previously are based on the principle of extracting the contaminants from the water samples after collection, or direct identifica-tion/quantification of determinants. Systems are also available for concentrating and/or extracting contaminants directly in the field. These systems take advantage of the tendency of determinants with low water solubility to bind to specific solid materials (solid-phase extraction [SPE]) or the fact that a determinant is more soluble in specific solvents (liquid-liquid extraction) than in the water phase. 

---