Respirators and

Students should distinguish carefully between the animal charcoal used for decolorisation, and the wood charcoal which is used for absorbing easily liquefiable gases, and which is therefore used in gas respirators and also, when chilled in liquid air, for obtaining high vacua. 

Remove the patient to the fresh air, and loosen clothing at the neck. If breathing has stopped or is extremely w eak, gh e artificial respiration and continue until the patient is transferred to hospital or until a doctor arrives. 

Porphyrins and chlorophylls are the most widespread natural pigments. They are associated with the energy-converting processes of respiration and photosynthesis in living organisms, and the synthesis of specific porphyrin derivatives is often motivated by the desire to perform similar processes in the test tube. The structurally and biosynthetically related corrins (e.g. vitamin B,j) catalyze alkylations and rearrangements of carbon skeletons via organocobalt intermediates. The biosyntheses of these chromophores are also of topical interest. 

Reactions at the aromatic nucleus that are quite different from the usual mild condensations and rearrangements which apparendy generate the typical alkaloids already discussed must be iavolved. Securinine (137) is reported to stimulate respiration and increase cardiac output, as do many other alkaloids, but it also appears generally to be less toxic (98). 

Beneficiation faciUties require air and water pollution control systems, including efficient control of dust emissions, treatment of process water, and proper disposal of tailings (see AiRPOLLUTlON CONTROLMETHODS). In handling finished fluorspar, operators must avoid breathing fluorspar dust and contacting fluorspar with acids. Proper disposal of spills and the use of respirators and other personnel protective equipment must be observed. Contact with fluorspar may irritate the skin and eyes. 

Mg(OH)2 powder is classified by OSHA as a nuisance dust. ACGIH categorizes the powder form as particulates not otherwise classified. Exposure limits are as follows (108) ACGIH 10 mg/m , OSHA 5 mg/m (respirable), and 15 mg/m (total). Magnesium hydroxide is reported in the EPA TSCA inventory (109). 

Potassium [7440-09-7] K, is the third, element ia the aLkaU metal series. The name designation for the element is derived from potash, a potassium mineral the symbol from the German name kalium, which comes from the Arabic qili, a plant. The ashes of these plants al qili) were the historical source of potash for preparing fertilisers (qv) or gun powder. Potassium ions, essential to plants and animals, play a key role in carbohydrate metaboHsm in plants. In animals, potassium ions promote glycolysis, Hpolysis, tissue respiration, and the synthesis of proteins (qv) and acetylcholine. Potassium ions are also beheved to function in regulating blood pressure. 

The modes of action for niclosamide are interference with respiration and blockade of glucose uptake. It uncouples oxidative phosphorylation in both mammalian and taenioid mitochondria (22,23), inhibiting the anaerobic incorporation of inorganic phosphate into adenosine triphosphate (ATP). Tapeworms are very sensitive to niclosamide because they depend on the anaerobic metaboHsm of carbohydrates as their major source of energy. Niclosamide has selective toxicity for the parasites as compared with the host because Httle niclosamide is absorbed from the gastrointestinal tract. Adverse effects are uncommon, except for occasional gastrointestinal upset. 

For handling chi orohydrin s, chemical safety goggles, chemical-resistant gloves, OSHA/MSHA approved respirators, and other protective clothing are required. In case of contact, one should immediately flush eyes or skin with copious amounts of water for at least 15 minutes and remove contaminated clothing and shoes. If inhaled, the person should be moved to fresh air (72). 

The places from which pollutants emanate are called sources. There are natural as well as anthropogenic sources of the permanent gases considered to be pollutants. These include plant and animal respiration and the decay of what was once living matter. Volcanoes and naturally caused forest fires are other natural sources. The places to which pollutants disappear from the air are called sinks. Sinks include the soil, vegetation, structures, and water bodies, particularly the oceans. The mechanisms whereby pollutants... 

Because a filter sample includes particles both larger and smaller than those retained in the human respiratory system (see Chapter 7, Section III), other types of samplers are used which allow measurement of the size ranges of particles retained in the respiratory system. Some of these are called dichotomous samplers because they allow separate measurement of the respirable and nonrespirable fractions of the total. Size-selective samplers rely on impactors, miniature cyclones, and other means. The United States has selected the size fraction below an aerodynamic diameter of 10 /xm (PMiq) for compliance with the air quality standard for airborne particulate matter. 

An employer has speeifie obligations to ensure all eontrol measures are kept in an effieient state, effieient working order and good repair. Engineering eontrols should be examined and tested at suitable intervals, e.g. loeal exhaust ventilation equipment must be tested at least onee every fourteen months, and more often for proeesses speeified in Table 5.23, and a reeord kept. Respirators and breathing apparatus must also be examined frequently and the eheeks reeorded. 

If in doubt, provide air-fed respirators and follow the requirements for entry into confined spaces (Chapter 13). 

Use respirators and face protection etc. when changing regulators on cylinders of toxic gases. 

General methods for sampling and gravimetric analysis of respirable and inhalable dust... 

Table 13.9 Assigned Protection Factors for Respirators and Breathing Apparatus ...

Cadmium and inorganic compounds of cadmium in air (X-ray fluorescence spectroscopy) Chromium and inorganic compounds of chromium m air (atomic absorption spectrometry) Chromium and inorganic compounds of chromium m air (X-ray fluorescence spectroscopy) General methods for sampling and gravimetnc analysis of respirable and mhalable dust Carbon disulphide in air... 

Chemical. Where severe chemical contamination is suspected, specific precautions must be followed if OSH A action levels are approached. Such instances rarely occur in LAQ investigations. One possible exception might be a pesticide spill in a confined space. In this case, an appropriate respirator and disposable coveralls may be needed. 

---