Unit 1
Compare industrial hygiene and occupational hygiene
The terms refer to the same concept; nonetheless, their use may be dependent on a person’s geography. In Australia and UK, occupational hygiene is preferred while in Latin America and The US the term industrial hygiene is more common. However, a minor difference exists between occupational and industrial hygiene. Occupational hygiene covers a wide range of work places; conversely, industrial hygiene is limited to industrial settings.
Name the professional associations for occupational/ Industrial hygiene
The associations are: IOHA which stands for International Occupational Hygiene Association, AIHA-American Industrial Hygiene Association, ACGIH-American Conference of Governmental Industrial Hygienists, BOHS-British Occupational Hygiene Society and ultimately AIOH – Australian Institute of Occupational Hygienists.
Describe the qualifications required for an occupational hygienist in Australia
Occupational hygienists must be capable of handling challenges adequately in their profession. One must have worked for five years or more. The occupational hygienist needs to have the proper academic qualifications.
Outline the ethical obligations of the occupational hygiene profession
All occupational hygienists are obligated to practice in accordance with their fields of competence. No one should give information freely; only legal and health reasons can impose an exception. Professionals should follow the code of conduct. They need to offer help concerning probable risks in occupations. Workers may sometimes put themselves at risk; occupational hygienists need to warn them about taking precautions. Members of this profession are expected to act with integrity. They need to abide by scientific principles within the profession; these govern workers’ safety and well being.
You have prepared a report on a hazardous exposure that includes high monitoring results. Your client or manager asks you to retain the results but delete any other comments. Outline your response.
In response to the situation, I would first try talking to the manager in order to sensitise him about the importance of the recorded comments. I would let him know that very serious dangers could emanate from hazardous exposure of the workers. It would probably be a good idea to have proof that such a conversation existed between the client or manager and me. This would ensure legal protection. If the client insists on deletion, I would stop working for him. (Bluff, 2004)
Summarise the development of occupational hygiene since 1901
Occupational hygiene started in South Africa specifically because dust exposure was found to be a health concern. Consequently, the profession established a level of dust that would not put people at risk by analysing the air around those areas. In subsequent years, it was established that people’s exposure to dust could be monitored medically through the use of x-rays. In the next decade; up to and including the First World War, a lot of industries started emerging. Industrial hygiene became a major concern. It was at that time that Industrial Hygiene and Sanitation (Changed to Division of Industrial hygiene of the Nation in 1937) was created within the United States; this occurred in 1914. Later on, the Air Hygiene Foundation (Changed to Industrial hygiene foundation in 1941) was established in 1935 after the public voiced concerns about a tunnel project in West Virginia. In 1937, an association for industrial hygiene practices was created. In 1960, the American Board of Industrial Hygiene was formed to certify hygienists all around the country.
What lessons does the historical silica experience have for contemporary occupational hygiene?
The silica issue revealed that this profession still needs to work on evaluative techniques for prevention of such occurrences in the future. Nonetheless, some lessons have been learnt from it. The silica issue was a platform against which certain specialities could emerge in the profession. A number of new entities were formed in order to respond to these respective issues. It also led members of the profession to become aware of the importance of reproducibility of results. Measurement methods have improved dramatically in this profession owing to the experience. These can be carried forward in the detection of other substances. Manufacturers need to realise they can minimise risks that their staff are exposed to by utilising medical findings on prevalence of a certain substance. They need to ensure that these are synchronised with engineering controls that operate within the institution. Additionally, industrial operating procedures should be aligned with scientific findings so as to protect workers.
How does the occupational hygiene approach of anticipation, recognition, evaluation and control compare with the risk management approach of identify, assess and control?
The anticipation, recognition, evaluation and control approach differ from the-identify-assess-and-control approach because in the latter strategy, major focus is on prevention rather than mitigation. Here, risks are usually detected before they take place and suitable measures are put in place in order to tackle them. A lot of speciality is involved in such a process because some hazards maybe obvious while others maybe hidden, but just as risky. Conversely, the identify-assess-and-control plan dwells on the quantifiable risks that exist in a certain workplace. Once assessments have been made, then actions are taken in order to mitigate those risks. It should be noted that comparisons to prevailing industry standards are normally done in the first strategy compared to the second. In addition, the second approach dwells on physical information while the first approach depends upon experience and data or information. Lastly, the second method puts an organisation at a greater risk than the first approach because it will only focus on those extreme situations that maybe out of control already.
Unit 2
How are TWA exposure standards used in the working environment?
Time weight average exposure standards are a method of assessing the level of exposure of airborne contaminants. TWA exposure standards are used in the work environment through an assessment of exposure levels during a specified period of time. Usually, this occurs over a period of 5 days in the week and eight hours of exposure per day. TWAs are compared with exposure standards and if the former are found to be higher than the latter than the health of the respective worker is said to be at risk. However, exceptions can be made if workers do not remain inside the work premises (under exposure) all day long; precautions should be taken. (Mayhew & Peterson, 1999)
What is the difference between STEL value and peak/ ceiling values?
STEL encompasses only short term exposure levels. The term refers to the amount of airborne concentration that is permissible within a period of 15 minutes in a normal working day (normal refers to an eight hour working day). No one should exceed the STEL concentration for more than 15 minutes, 4 times in a day. The interval between exposure times ought to be 1 hour. STEL values are more appropriate when substances under consideration are likely to lead to adverse health effects if short term exposures occur. Conversely, peak values do not involve concentration averages. They are appropriate for substances (Like irritants) that can cause certain health effects even at the slightest exposure times. However, their concentration is what peak values are used to measure. Although both measures can be used as guidelines that determine how much of a particular substance one can be exposed to, one of the values –STEL- is time bound while the other –peak value- is defined by concentration levels.
What proportion of workers should “nearly all workers” cover?
“Nearly all workers” should encompass close to all the workers who do not show any intense health effects after continuous and increased exposure to threshold values of the substances in their workplace. Minor exceptions are permissible for workers who react to lower concentrations of the concerned substances by illustrating slight uneasiness. Exceptions also exist for those workers who are regarded as extremely sensitive to the exposure of the substances as they may get sick.
TWA exposure standards normally cover eight hour shifts. What should be done about variable length shifts?
Workers that are exposed to longer durations of work shifts may be at a greater risk, so the TWA exposure standards ought to be adjusted. Specific emphasis should be given to the half life of the substance. If substances have half lives of less than three hours then the TWA values should remain as they are. This is because workers are not exposed to the substances long enough for them to have an adverse effect on their health or safety. However, if half life lies between three to four hundred hours, then the substance can stay in the atmosphere long enough to cause damage to workers. The TWA exposure standards need to be reduced using the following formula:
Exposure standard reduction = (8/h)*(24-h)/(16)
H=duration of work shift
For substances with half lives that exceed four hundred hours, daily limits of exposure should be found through average values found from the forty hour week specification.
Workers whose shift is less than 8 hours should use the standard as it is.
What are the limitations of exposure standards?
Exposure standards are limited by the nature of a worker’s health and biology. Some workers are more sensitive than others and may be affected at concentrations that fall below the exposure standards or even at levels above them. The standards are based on certain time assumptions such as eight-hour working days. Unless calculations are done in order to adjust these standards, then workers may not be safe. The standards are valuable for products that have no carcinogenic effects. It is also problematic to apply these exposure standards to workplaces that contain a mixture of substances. The combination of all of substances increases the health risks involved because they create a synergistic effect. Exposure standards are based on substances that are inhaled into the body. If a substance can seep in through the skin, this exposes workers to greater concentrations of the substance in their bodies. The values are often absolute and make it difficult to compare them with other substances in double exposure.
How do exposure standards for eight hour shifts apply when a worker works for longer than eight hour shifts?
The formula for exposure standard reduction will be useful in such instances. The value obtained from that calculation should be subtracted from the stated exposure standards so as to protect workers from these excessive dangers. The reason is that most workers are exposed to such situations even without having knowledge about them. It may sometimes be necessary to look at whether the exposures standards cover long term and short-term effects. The latter situation does not warrant any changes but the former does. Intensity of the workload also has an effect on the exposure levels so it should be considered. Industries / workplaces should use expert advice in order to modify their exposure values.
How do you assess acceptable exposures for materials that do not have exposure standards?
Exposure standards come in handy because they allow industries to monitor exposure levels. If they do not exist, then this function should not be carried out. Managers and other administrators need to try and determine exposure levels through mechanisms available to them. One method is the chemical abstract service registry number. Another approach would be name association. The establishment can look for certain chemicals that have exposure standards and are synonymous to the ones being used. However, if all strategies fall short and the company fails to find clues, then exposure levels should be kept at a minimum. (Perkins, 1996)
Are exposure standards useful in the control of biological hazards?
Biological hazards are different from typical hazards because they are complex in nature. Sometimes they may spring from physical objects while in other instances they may actually come from people. Assessment of these probabilities is close to impossible. Biohazards are difficult to quantify because they tend to increase in the body through replication. In these cases, concentration levels are not useful in assessments since a worker’s health may be at risk even at the slightest exposure levels. Classification procedures for biohazards depend upon the type of risk imposed by that category; exposure standards have no place in this area and should be left out.
Unit 3
Why are occupational hygiene samples collected?
Workers can be put at risk when exposed to excessive contaminants. Sample collection allows firms to assess the level of hazards that their workers are exposed to in order to minimise it. Industries need to have evidence that they abided by occupational safety requirements. This is because the government requires them to comply and so do health insurance providers. The samples can also be quite applicable if a company faces compensation claims from a certain worker. These can be used as evidence that the firm is abiding by regulations. In other words, they are a form of record keeping. Quality system procedures can also be duly maintained through this procedure. Besides, companies with safety programs in place often require such data.
Which workers should be asked to participate in a sampling program?
The workers that can participate in a sampling program are those ones that represent the largest proportion of employees in the industry. Their exposure levels need to be sufficient enough to warrant consideration. Their jobs need to reflect the ones carried out by majority of employees in that place of work. Alternatively, it could be that their job takes place in a central area where most of the staff are also found. Companies should stick to the employees who possess the above mentioned traits (Erickson, 1996).
What is a homogenous exposure groups (exposure zone)
A homogenous exposure group is one that possesses similar exposure levels. This consists of workers who are stationed in the same working zone or area and are thus exposed to similar concentration levels. It can encompass those employees who have identical job types and hence similar risk levels. Industrialists should take caution when working with these groups. They need to be aware of other factors that may affect exposure groups as these dynamics may alter their level of homogeneity. For instance, if workers keep moving between work stations, then they may no longer belong to the same homogenous exposure group. Distant locations from highly concentrated substances are not safe because of movement of air.
Most occupational exposure data is log normally distributed. What does this mean in practice?
Log normally distributed data refer to those values that have a straight line when a graph of the log of cumulative values versus the log of the actual values is plotted. The graph is said to be normally distributed because when the absolute values are plotted, a normally distributed curve will emanate. The median of these values is greater than the mode, while the mean is the greatest of the three. In practice, occupational exposure data is utilised because it ensures that chemical and physical properties are assessed objectively. Absolute concentrations tend to vary from time to time so using log normally distributed data overcomes this challenge. Once the graph has been created, a straight line will emerge for the values. However, those values that fall away from this line can be easily detected and corrected. They can be used as warning signs that certain regions are not alright. Usually, this line indicates the permissible exposure limit for workers.
How many samples should be collected?
First, the total number of workers that carry out specific tasks should be established as this serves as a crucial starting point for the rest of the process. Thereafter, the square root of this number should be calculated. Samples collected should then respond to the latter value. For example, if the staff members working on a given task are 64, then number of samples to be collected from that work group should be eight.
Contrast personal and area samples
Personal samples differ from area samples because they focus on inhalation areas or breathing zones while area samples dwell on open areas. The exposure levels for area samples are normally collected through placement of a fixed device in a certain working station or a person may move with the instrument as he or she collects samples around a definite location. Exposure amounts for personal samples are collected by placement of a device on a worker’s collar; this is about 3cm from the nose and the mouth. Samples can then be used to estimate the inhalation levels of exposure to contaminants by the workers. Personal samples are more accurate than area samples when focusing on individual values. On the other hand, area samples are more appropriate if an organisation needs to establish the level of contamination at ambient levels. It is also more effective than personal samples when sources of the contaminants need to be traced during indoor investigation and for instatement of engineering controls. Area sampling can complement personal sampling. (Tillman, 2007)
Describe the uses and abuses of markers
Markers are used to minimise exposure to toxic mixtures that may be prevalent within a work area. In other words, they are used during regulations. They can also be applied in epidemiological analyses. Upon suspecting a toxic agent, markers can help in reducing analytical costs. The same benefits apply even to known agents. Abuses usually come in the form of using the marker for analyses of exposure levels to a myriad of mixtures. This usually results in qualitative inaccuracies. Markers can also be misused when dealing with complex mixtures that contain unknown agents. Eventually, this will lead to confusion as the marker may sometimes be assumed to be the active agent.
Describe the data required to be collected in a good occupational hygiene record?
One should collect data about worker exposure levels. Sometimes this can be done for statistical purposes, research purposes and epidemiological purposes. Data should also be collected on exposure related illnesses such that working conditions can be checked for safety. Recordings for the data collection and analysis methods need to be done. Here, calibrations and naming of the samples should be provided. In the analytical process, one should record information about evaluation and monitoring of exposure levels. Work schedules should also be provided. Additional employee data needs to be recorded as well; these include medical records. Pictures can also be used. It will be necessary for the respective hygienists to record any environmental audits that may have been done and these should be linked to individual staff records. Any other information that can affect exposure levels should be recorded in a comprehensive, detailed and well structured manner.
Unit 4
What do you understand by the term aerosol?
Aerosols are solids that cause adverse health effects when inhaled into the body via the respiratory system. The solids must be suspended in gases or liquids and should have stayed there for a long time. Their sizes should also be quite small. However, as a rule most aerosols have varied densities, chemical compositions, sizes and shapes. They may come from various industrial and mining processes. They can be found in smoke as a mixture of fumes, particulates, vapours and gases. Such smoke may be released during combustion of carbon based products. Aerosols can also come from smelting and welding processes; they can also be released from food industries in the form of bio aerosols and droplets. Dust, pesticide sprays, aerosol sprays and asbestos or fibrous particles are also other well known types of aerosols. (Quinlan & Bohle, 2000)
Describe the three main particle size fractions
Particles can be small, medium or large. The aerodynamic diameter of the middle sized particles is about 10-100μM. They are classified as dust that is inhalable in nature. subdivisions include coarse and thoracic particles. They can get into the respiratory system thus leading to mucous production, irritation and cancer too. Once these particles get into the body, they settle in the bronchi of the lungs or the bronchioles and other nasopharyngeal areas. Large particles have an aerodynamic diameter of 10-20μm; they do not pose substantial danger to workers because they cannot be inhaled. Lastly, particles can be small sized; they are quite hazardous because they settle in the lungs in specific tissues such as the alveoli. As a result, the particles can lead to cancerous cells, fibrosis of the lungs as well as alveolitis, which are all dangerous conditions that can be fatal. Sometimes the relative small sizes of the particles may cause them to come out of the body through exhalation, but others can still be retained.
There are several methods for sampling inspirable dusts. How do the methods differ?
Personal sampling is preferable for inspirable dusts. It can be done through 3 types of sampling devices, i.e., the single-hole sampler, 7-Hole sampler and the IOM sampler. The latter kind is the most superior because it meets inhalable deposition curves and all materials that have been collected are analysed through the use of an internal cassette. It functions by pump connection. Conversely, the single-hole sampler does not have much use as its performance is comparable to the total dust sampler. It is only appropriate for lead sampling. The 7Hole sampler lacks a cassette and does not allow weighing of samples through the filter. Wind easily affects it and the device also tends to undersample large particles.
What are the desirable features of an air sampling pump for occupational hygiene monitoring?
The pump needs to have a battery with prolonged life so as to accommodate full shift sampling. Furthermore, it should possess a timer and a setting for programming so as to increase handiness. The tool needs to be as light as possible in order to allow mobility during the sampling process; this is especially true for personal sampling. Lastly, when dust load increases, a sampling pump needs to regulate changes in filter back pressure or it should adjust flow.
What are some of the uses and limitations of instantaneous particulate monitors?
Instantaneous particulate monitors are greatly useful in the process of reading exposed hazardous substances directly. No time needs to be wasted in sending the sample for laboratory analysis. Control measures in commissioning, prior to and after monitoring and test controls can be tested through the machines. The monitors are very effective in identification of high exposure materials thus minimising possible health hazards. One of the limitations of this machine is that it requires calibration of its devices. Consequently, use of the monitors can become a very cumbersome and inconvenient experience. It is quite expensive to buy and maintain. Additionally, every category of dust needs to have its own calibration. As a result, one cannot use it for legally based compliance testing. The monitors lack a mechanism for differentiating fibres and dusts that may be prevalent at work.
How is dust sampling equipment calibrated?
Calibration devices can either measure volume or flow. Flowmeters include critical orifices, rotameters, and velocity meters which are designed to measure the velocity of air. Volume measurement calibrators include wet test meters, bubble burettes, dry and wet gas test meters. In the calibration process, enough values ought to be represented in order to accommodate any scale variations. Furthermore, there should be ample room to include all the flow rates that will need to be measured. In the calibration process, one should start by selecting standards, which maybe primary or secondary, and then proceed with the calibration. Primary standards are selected because of minimal instances of error. Secondary standards are selected for backup purposes.
What are some of the factors that can cause errors in particulate monitoring?
Sampling equipment can be a serious source of error especially if the hose or the pump is faulty. Specific issues that can arise include battery failure, disconnection of the hose or incorrect connection, a mechanically damaged hose, hose kinks that lead to pump stoppage or minimal air pumping within the system and an underpowered pump. If flawed sampling strategies have been selected, then one is also likely to record an error in performance. Examples here include: choosing the right flow rates or the right size fractions. Filters can also lead to poor particulate monitoring. In such cases, the wrong type of filter may have been selected. The filter may also have one or more tears or sheds. Personal challenges such as employee or employer interference through lost pumps, addition of dust to the sample head, switching of the pump and altered work schedules can lead to monitoring errors. (Gardiner & Harrington, 2005)
Describe some of the problems of sampling and analysis of fibres
Fibre analysis is based on fibre numbers rather than masses of the fibres themselves. Because of this, it may be complicated to carry out the procedure. First the sample must be single layered, and in order to ascertain that this is so, its morphology must be scrutinised using moderate type of magnification. Any samples that have clumps cannot be used. A lot of attention also needs to be given to the size of the fibres for asbestos. Diameter and length of the fibre determines how respirable it is. As such, only fibres with a width of 3μm or less; length 5μm or more and length and width ratio of one to three can be analysed. Fibres are also challenging to analyse because they require only samples from graticule locations. Any other sources will be regarded as useless in the analysis. Lastly, handling of the fibres may also be another big challenge in the analysis. If transportation is done poorly such that some vibrations are created, then this could mess it all up. Mishandling of the sample also dislodges the fibre from the filter.
Unit 5
What is a gas, what is vapour?
A vapour is a type of gas that exists as a liquid when pressure and temperature of its surrounding is at room temperature. Vapours may include: organic vapours, which come from solvents, and water vapour. In industrial hygiene, focus is given to organic vapours mostly; they also come from volatile liquids. Examples of such substances include toluene and benzene. In a few of the cases, vapours may also emanate from inorganic substances like mercury.
Gases are substances which are fluids at room pressure and temperature, and will expand to fill up the volume they are occupying. One cannot condense gases at room temperature. Common examples include carbon monoxide, oxygen and nitrogen. Industrial hygiene often focuses on inorganic compounds and elements. Examples are hydrogen cyanide, chlorine and ammonia. (Confer & Confer, 1999)
How are gases and vapour samples collected?
Gases and vapour samples can be collected through passive or active sampling depending on whether area or personal sampling has been chosen. Passive sampling entails a gas detector that uses a passive bubbler in liquid sorbent or an electrochemical cell. The mechanism behind its operation is diffusion of the gases or vapours. In certain instances, one can get a direct reading while in others, it may be necessary to take the sample to the lab for analysis. If whole air methods are in use, gas bags, aerosol cans, glass tubes and passivated canisters may be of use. Some can offer direct readings while others require lab analysis. In personal active sampling, one needs to use a vacuum or a pump to bring the sample into a medium. Sometimes the detecting device may be the one that contains the pump and a battery. On the other hand, the pump can be connected manually. However, if other methods are not available for personal sampling, then the bag method can be used.
What are the constraints in passive sampling that are not relevant to active sampling?
No back up section exists for samplers in passive sampling, yet this exists in active sampling; users may refrain from using it. Passive sampling requires minimum air movement and this means that it is so restrictive. The method necessitates heavy recurring costs.
Discuss the criteria that should be used in the selection of a direct reading instrument
Direct reading instruments need to give instant results when in use. No radio frequency interference should affect the instrument. It should be able to yield results in a short period of time. When contaminants can lead to acute effects, then the instrument should be able to read high short term exposures. The instrument should be capable of estimating long term exposure using correct sampling procedures. Alarm functions should also be prevalent.
Describe a method of gas or vapour calibration
In calibration, one has the option of using a primary standard (like a bubble tube or a soap film flowmeter) versus a secondary standard (such as an electronic flow rate meter or a rotameter). Direct reading of gas detectors can be done at standard atmospheres for aerosols, gases and vapours. However, most persons use a small cylinder of the sampled vapour or gas at a specific concentration as the method of calibration. Alternatively, a polymer bag may also be applicable. One should carry out a field check (or a bump test) prior to and after completion of monitoring. Full calibrations need to be taken to the lab.
What are some of the problems of using detector tubes?
If different contaminants are being assessed, then different detector tubes will need to be used, each detector will vary in terms of the time needed for colour development, strokes to be used, effects of atmospheric pressure, humidity requirements and temperature requirements. A lot of time will be wasted in trying to set up the valves in every tube so that they can all measure volume accurately. If contaminants are prevalent in low levels in the atmosphere, the detector tubes may not be the best since they are not sensitive enough. Some factors can mess up the possibility of getting accurate readings; for instance: the sampling rate, the actual air volume, the granular packing, airflow patterns and other interferences. Types of manufacturing, the age of the tube and storage will determine accuracy and reproducibility. (Australian Council of trade Unions, 2003)
Describe the methods for the identification of asbestos in buildings
In order to identify asbestos in a building, competent people should engage in this endeavour. They must consider almost every aspect of a building if suspicions of asbestos are prevalent. The product may be found in several types of locations within the building. Nonetheless, it is likely that most of the products will be found in materials that are friable or materials that have been proven to contain asbestos. Additionally, those materials that are susceptible to damage should also be considered. Examples of such building materials include: insulation pipes in furnaces or insulation for fire retardant products, cement products with asbestos, roofs, and acoustics especially in false ceilings.
How are asbestos hazards controlled in buildings?
Once identification of asbestos has been done then the best remedy should be to remove it from the building; this may prove to be quite costly. One could instate measures that would cut the amount of contact between the materials and workers, or materials and the environment. Companies can achieve this aim by placing a barrier on top of the material. One may find appropriate coatings that can cover it up. Employers can seal the asbestos based products as well. It is possible to find asbestos residues in the workplace. To avoid harmful effects, residues should be eradicated. Frequent inspections will assist greatly in the minimising exposure.
Unit 6
What is biological monitoring?
Biological monitoring is the process of assessing exposure to hazardous products through analysis of the body fluids and measurement of reversible biological changes. The procedure is done in order to quantify the level of exposure within a subject. Only occupational hygienists can carry this out; although they may get help from health-care experts. Sometimes, air sampling may not yield representative or accurate results. Consequently, businesses can use biological monitoring to get dependable results. Air sampling can fail because it focuses on inhalation, yet contaminants may get into the body through the skin or the mouth.
What media are used to make biological monitoring measurements? Which are the most common?
Body fluids are the main media that provide exposure information in biological monitoring. Some of them include urine, breadth, hair and blood. However, urine and blood are the most commonly used; with urine as the first then blood. Some subjects may consider blood samples as invasive because they must be drawn out of the body. In such circumstances, urine samples are preferred. (Tranter, 2004)
What are the advantages and disadvantages of biological monitoring?
The main advantages of biological monitoring include: ability to determine contaminant exposure using different pathways, ability to reconstruct past exposure, ability to detect exposures that may not be work related, ability to give extra information about individual risks and the ability to test control measure effectiveness.
Major disadvantages include the invasive nature of the method. If blood samples are being collected, then the method may be objectionable to some people because it is invasive. Personal factors like health status and diet can interfere with the results. Before anyone can participate in the procedure, he or she needs to give informed consent to the person carrying it out. When results have been found, result confidentiality needs to be maintained by the industrial hygienist, yet those same employers need to protect their workers from overexposure. Exposure standards for this method are not easily available.
How can wipe tests be used to produce improvements in workplace conditions?
Wipe tests complement other measures of exposure levels in the workplace because they focus on the dermatological aspect of the issue. It should be noted that workers can be exposed to hazardous products through ingestion, skin absorption and inhalation. Most methods facilitate monitoring through inhalation but wipe tests allow exposure detection through dermal exposure. Besides, it has been shown that wipe tests are directly related to the amount of surface contaminant concentration, air concentration and dermal potential of absorption. Wipe tests therefore assist in the workplace because they contribute towards finding the total level of exposure that a substance has caused in the concerned industry or company. By measuring skin exposure, employers may be able to reduce prevalence of the substance at work. Nonetheless, the method can be highly variable.
Describe some of the sources of variability in biological monitoring
Variability in biological monitoring can be caused by worker’s personal habits such as their hobbies or the kind of drugs they take. Employees with preference for fishing may be exposed to lead, which is used to make sinkers. Secondly, diets can also lead to variability. Workers who take plenty of alcohol tend to report greater toxication. It may be the food that workers consume; those who take a lot of fish may expose themselves to arsen and this may change results. Chemicals found outside the workplace can also lead to variability. Fourth, it could be personal medication; as the person excretes, remains from that medicine can be found in the urine and this changes results. Fifth, the personal characteristics affect results since one’s hygiene practices, gender, body metabolism, age and body build are unique. Sixth, work related factors may be another source. Those who have a higher work rate will usually breathe at a faster rate and alter results. Workers may be exposed to different contaminants. (Benson & Benson, 1996)
How do biological monitoring results compare with air sampling results?
Biological monitoring tends to be more accurate than air sampling since it identifies exposure from all possible routes of entry. Air sampling on the other hand is restricted to the kind of exposure that only gets in through inhalation; hence such a method focuses on what could get into the body rather than what is already in the body. On the other hand, since biological monitoring measures exposure in the body, it may be possible to measure exposure that occurred outside the workplace. In other words, it is not limited to exposure at the job only. Biological monitoring reveals significantly high amounts of substances than air sampling so it should be considered for this purpose.
Describe the main dermal exposure assessment techniques
The chemical removal technique removes the product from the through the use of solvents like water-alcohol or water-surfactant mixers. Generally, washing applies to hands only. For the rest of the skin, one may want to consider wiping. Significant amount of hazards can be lost during the washing process, so only what is removed from the skin is measured and not the actual exposure level. One’s wiping or washing efficiency can alter the results. In the surrogate skin technique, a chemical collection medium is placed on the skin using a garment sampler or a patch. It is assumed that the collector will contain the same composition of chemicals as the worker’s skin then the collector is taken for analysis although overestimation of chemical exposure can occur. Sampling media have different absorption properties, so results differ. In the fluorescent tracer technique, video imaging is used in order to detect the presence of fluorescent materials on the skin. The method is non invasive, but one needs to use chemical tracers. Quality assurance is needed and protective clothing can interfere with the work.
What is the role of the occupational hygienist in biological monitoring?
In biological monitoring, the occupational hygienist is only interested in analysis of exposure levels i.e. assessment of reversible processes in the workers. Non reversible changes should be directed to a medical practitioner for analysis. In the biological monitoring process, one should be aware of sample collection procedures. One should also know about all the chemicals that can be identified through biological monitoring and the ones that cannot. The industrial hygienist needs to know how to carry out certain procedures that are done in biological monitoring; one example is venipuncture.
References
Benson, E. & Benson, S. (1996). Health and hygiene. London: ARISE foundation.
Bluff, E. (2004). OHS regulation for a changing world of work. Melbourne: Federation press.
Confer, R. & Confer, T. (1999). Occupational health and safety: terms, definitions and abbreviations. Sydney: Lewis publishers.
Erickson, P. (1996). Practical guide to occupational health and safety. Melbourne: Elsevier.
Gardiner, K. & Harrington, J. (2005). Occupational hygiene. NY: Wiley-Blackwell.
Mayhew, C. & Peterson, C. (1999). Occupational health and safety in Australia: industry, public sector and small business. NSW: Allen and Unwin.
Mayhew. C. & Peterson, C. (2005). Occupational health and safety: international influences and the new epidemics. Sydney: Baywood publishers.
Perkins, J. (1996). Modern industrial hygiene: Recognition and evaluation of chemical agents. NY: Van Nostrand Reinhold.
Quinlan, M. & Bohle, P. (2000). Managing occupational health and safety: a multidisciplinary approach. Melbourne: Palgrave McMillan.
Tillman, C. (2007). Principles of occupational health and hygiene. St. Leonards, NSW: Allen and Unwin.
Tranter, M. (2004). Occupational hygiene and risk management. NSW: Allen and Unwin.
Australian Council of trade Unions. (2003). ACTU occupational health and safety priorities. ACTU report, 32437269.