Aims I 3
To thoroughly appraise and evaluate the legal, theoretical and practical aspects of
identifying, controlling and managing the risk presented by a range of workplace ‘ I.”
hazardous agents and to integrate the concepts of healthy workplaces and health and .-I”
well being into occupational health and safety practice
Learning Outcomes
At the end of the module the successful student will be able to:
1. Critically appraise the relevant statutory and regulatory requirements for hazardous
agents in the workplace. .. F i
2. Exhibit critical insight into the general principles of occupational hygiene and
occupational health, the role of various personnel and justify and argue the various
approaches and strategies available to prevent and control hazardous agents in the
working environment. it H . i
3. Integrate health and wellbeing and the healthy workplace into professional practice
4. Critically appraise and evaluate chemical, biological, and physical, agents in the
workplace and justify the use of various field and laboratory techniques used to
identify and measure hazardous agents.
5. Argue the use of toxicological data in relation to the identification of work related ill-
health and construct and formulate strategies by applying the principles of
epidemiology to health surveillance of the workplace.
Syllabus
0 General aspects of Occupational Health and Hygiene with regards to professional
practice, competence, objectives and its relationship to other subjects areas within
the context of occupational safety and health.
0 Legal and theoretical aspects of managing hazardous agents from the statutory and 1.
regulatory obligations, Approved codes of practice and HSE guidance to the
professional body (5) guidance on practice and research within the area of j-
workplace hazardous agents and their effects on health. L.
Page 56 Programme Handbook 2015/16
Sulphur dioxide, (SO2), inorganic compound, a heavy, colorless, poisonous gas. It is produced in huge quantities in intermediate steps of sulphuric acid manufacture.
Sulphur dioxide has a pungent, irritating odour, familiar as the smell of a just-struck match. Occurring in nature in volcanic gases and in solution in the waters of some warm springs, Sulphur dioxide usually is prepared industrially by the burning in air or oxygen of Sulphur or such compounds of Sulphur as iron pyrite or copper pyrite. Large quantities of sulfur dioxide are formed in the combustion of sulfur-containing fuels. In the atmosphere it can combine with water vapor to form sulfuric acid, a major component of acid rain; in the second half of the 20th century, measures to control acid rain were widely adopted. Sulphur dioxide is a precursor of the trioxide (SO3) used to make sulphuric acid. In the laboratory the gas may be prepared by reducing sulphuric acid (H2SO4) to sulfurous acid (H2SO3), which decomposes into water and sulphur dioxide, or by treating sulfites (salts of sulfurous acid) with strong acids, such as hydrochloric acid, again forming sulfurous acid.
Sulfur dioxide can be liquefied under moderate pressures at room temperatures; the liquid freezes at -73° C (-99.4° F) and boils at -10° C (14° F) under atmospheric pressure. Although its chief uses are in the preparation of sulfuric acid, sulfur trioxide, and sulfites, sulfur dioxide also is used as a disinfectant, a refrigerant, a reducing agent, a bleach, and a food preservative, especially in dried fruits.
• Persons exposed only to sulphur dioxide gas pose no risk of secondary contamination. Persons whose skin or clothing is contaminated with liquid sulphur dioxide can secondarily contaminate rescuers by direct contact or through off-gassing of vapour.
• At room temperature, sulphur dioxide is a non-flammable, colourless gas that is heavier than air. Its strong, pungent odour and irritating properties usually provide adequate warning of its presence.
• Sulphur dioxide is readily absorbed through the upper respiratory tract; no data were located regarding dermal absorption. Sulphur dioxide is present in some foods; therefore, oral ingestion, although insignificant, is possible.
General Information
At room temperature, sulphur dioxide is a non-flammable, colourless gas with a very strong, pungent odour. Most people can smell sulphur dioxide at levels of 0.3 to 1 ppm. It is handled and transported as a liquefied compressed gas. It easily dissolves in water. The liquid is heavier than water. Although sulphur dioxide does not burn in air, cylinders of compressed liquid can explode in the heat of a fire.
Inhalation is the major route of exposure to sulphur dioxide. The odour threshold is 5 times lower than the OSHA PEL (5 ppm). Most exposures are due to air pollution, and this has both short-term and chronic health consequences for people with lung disease. Inhaled sulphur dioxide readily reacts with the moisture of mucous membranes to form sulphurous acid (H2SO3), which is a severe irritant.
Children exposed to the same levels of sulphur dioxide as adults may receive a larger dose because they have greater lung surface area: body weight ratios and increased minute volumes: weight ratios. In addition, they may be exposed to higher levels than adults in the same location because of their short stature and the higher levels of sulphur dioxide found nearer to the ground and because they are slow to leave the site of an exposure.
Ingestion of sulphur dioxide is unlikely because it is a gas at room temperature. Sulphur dioxide is used in small amounts as a food and wine preservative. Highly sensitive asthmatic individuals can develop bronchospasm after eating foods or drinking wine preserved with sulphur dioxide or other sulphur preservatives.
Sulphur dioxide gas is released primarily from the combustion of fossil fuels (75% to 85% of the industrial sources), the smelting of sulphide ores, volcanic emissions, and several other natural sources. It is a U.S. Environmental Protection Agency (EPA) priority air pollutant, but has many industrial and agricultural uses. It is sometimes added as a warning marker and fire retardant to liquid grain fumigants. Approximately 300,000 tons are used each year to manufacture hydrosulphites and other sulphur-containing chemicals (40%); to bleach wood pulp and paper (20%); to process, disinfect, and bleach food (16%); for waste and water treatment (10%); in metal and ore refining (6%); and in oil refining (4%). Toxic amounts of sulphur dioxide can be released from the preservative chemical metabisulfite in the presence of water and acid
Sulphur dioxide dissolves in water or steam to form sulphurous acid. Liquid sulphur dioxide corrodes iron, brass, copper, and some forms of plastic and rubber. Many metals, including zinc, aluminium, cesium, and iron, incandesce and/or ignite in unheated sulphur dioxide. Sulphur dioxide reacts explosively when it comes in contact with sodium hydride. Sulphur dioxide ignites when it is mixed with lithium acetylene carbide diamino or lithium acetyl ide ammonia.
Health Effects
• Sulphur dioxide is severely irritating to the eyes, mucous membranes, skin, and respiratory tract. Bronchospasm, pulmonary oedema, pneumonitis, and acute airway obstruction can occur.
• Inhalation exposure to very low concentrations of sulphur dioxide can aggravate chronic pulmonary diseases, such as asthma and emphysema. Certain highly sensitive asthmatics may develop bronchospasm when exposed to sulphur dioxide or sulphite-preserved foods.
• Sulphur dioxide reacts with water in the upper airway to form hydrogen, bisulfide, and sulphite, all of which induce irritation. As a result, reflex bronchoconstriction increases airway resistance.
Sulphur dioxide dissolves in the moisture on skin, eyes, and mucous membranes to form sulphurous acid, an irritant and inhibitor of mucociliary transport. Most of the inhaled sulphur dioxide is detoxified by the liver to sulphates and excreted in the urine. The bisulfide ion produced when sulphur dioxide reacts with water is likely to be the main initiator of sulphur dioxide-induced bronchoconstriction.
Sulphur dioxide respiratory irritation induces symptoms such as sneezing, sore throat, wheezing, shortness of breath, chest tightness, and a feeling of suffocation. Reflex laryngeal spasm and oedema can cause acute airway obstruction. Bronchospasm, pneumonitis, and pulmonary oedema can occur.
Some individuals are very susceptible to the presence of sulphur dioxide and overreact to concentrations which, in most people, elicit a much milder response. This hyper reactive response occurs the first time the individual is exposed and is therefore not an acquired immune or “hypersensitivity” response.
Acclimatization (a physiological adjustment of the individual to environmental changes) may also occur in up to 80% of exposed individuals. This is not necessarily beneficial although exposure may become less subjectively objectionable upon continuous or repeated exposure.
Asthmatics who are sensitive to sulphites in food can develop bronchospasm or an anaphylactic reaction. Sulphur dioxide, along with other components of air pollution, can exacerbate chronic cardiopulmonary disease.
Sulphur dioxide is a severe skin irritant causing stinging pain, redness, and blisters, especially on mucous membranes. Skin contact with escaping compressed gas or liquid sulphur dioxide can cause frostbite and irritation injury.
Because of their relatively larger surface area: body weight ratio, children are more vulnerable to toxicants that affect the skin.
Conjunctivitis and corneal burns can result from the irritant effect of sulphur dioxide vapour or escaping compressed gas, and from direct exposure to the liquid.
Reference List
sulfur dioxide, (2015) Available at: http://www.factmonster.com/ce6/sci/A0847158.html (Accessed: 25 October 2015).
vailable at: http://www.atsdr.cdc.gov/toxfaqs/tfacts116.pdf (Accessed: 25 October 2015).
