Lesson 3 – Airborne Pollutants

TERMS AND DEFINITIONS

“Airborne Pollutant” means any substance in the air that is harmful to health, including dust, fumes, aerosols, fibres, vapours or mists;
“Analysis methodology” means analysis techniques used to quantify a pollutant collected on or in sampling media (e.g. gas chromatography/mass spectrometry);
“BEI” means Biological Exposure Index;
“BML” means Barberton Mines (Pty) Limited;
“COP” means Code of Practice;
“DMR” means the Department of Mineral Resources;
“Dose” means the amount of a pollutant to which a person is exposed;
“Exposure” means the subjection of a person to an airborne pollutant in the course of employment through any route of entry (e.g. inhalation, ingestion, skin contact, or absorption.)
“HEG” means a homogenous exposure group;
“Homogenous exposure group” means a group of employees who experience pollutant exposures similar enough that monitoring exposures of any representative sub group of employees in the group provides data useful for predicting exposures of the remaining employees;
“ICP” means Inductively Coupled Plasma;
“MOHAC” means Mining Occupational Health Advisory Committee;
“Monitoring,” means the repetitive and continued observation, measurement, and evaluation of health and/or environmental or technical data, according to prearranged schedules, using nationally or internationally acceptable methodologies;
“MHSA” means Mine Health and Safety Act, 1996 (Act 29 of 1996);
“MSDS” means Mines Safety Data Sheet;
“NIOSH” means the United States National Institute for Occupational Safety and Health;
“OEL” means Occupational Exposure Limit;
“OESSM” means Occupational Exposure Sampling Strategies Manual;
“PPE” means Personal Protective Equipment;
“PTO” means Planned Task Observations;
“SAMOHP” means South African Mines Occupational Hygiene Programme Code Book;
“SANS” means South African National Standards;
“Significant airborne pollutant” means any airborne pollutant to which any employee is exposed in concentrations equal to or exceeding the hazard limits contemplated in regulation 9.2.1;
“SOP” means Standard Operating Procedure;
“TMM’S” means trackless mobile machines;
“90th Percentile” means the value, which must be used to determine when HEG’s need to be re-classified. This value can be calculated by:

a) Using Microsoft Excel Programme (percentile function); or
b) First placing all sample results in order from the lowest concentration to the highest concentration (i.e. concentration of specific contaminants). Next, assign each sample result a number, starting with the number 1 for the lowest concentration result up to the highest concentration being given the number equal to the total number of samples collected in that HEG. Multiply the total number of samples collected by 0.9. The sample result with the number corresponding to this calculated value is the 90th percentile.

– BP: Barometric Pressure in kPa.
– DPM: Diesel Particulate Mater
– HCS: Hazardous Chemical Substances.
– HEG: Homogenous Exposure Group.
– Mg/m3: Milligram per cubic metre.
– MSDS: Material Safety Data Sheets.
– MSV: Milli Sivert.
– OEL: Occupational Exposure Limit.
– PAH’s: Poly-nuclear Aromatic Hydrocarbons.
– PI: Pollutant Index.
– PPE: Personal Protective Equipment.
– PPM: Parts Per Million.
– TWA: Time weighted average. The average level accumulated during a study, but calculated with an eight-hour integration time.
– TWA-Con: Time weighted average concentration of the pollutant.
– VOC’s: Volatile Organic Hydrocarbons

RISK ASSESSMENT MANAGEMENT

This Code of Practice is based on Risk Assessment Principals in accordance with the MHSA.

Three types of risk assessment have been integrated, viz:
– Baseline risk assessment;
– Issue based risk assessment;
– Continuous risk assessment

Criteria for a significant hazard:
– Airborne pollutants` ≥10% of the applicable OEL;
– Gases/Vapours ≥50%

Risk assessment information.
Relevant information from historical gravimetric sampling results was considered and compared with the latest information available.
All historical Occupation Hygiene incidents were considered during the assessment process.
Relevant processes and activities were assessed during the risk assessment process.

In addition to the continuous risk assessment process the COP will be reviewed and updated after any serious incident relating to airborne exposure to employees.

OCCUPATIONAL HEALTH PROGRAMME –
KEY ELEMENTS FOR THE COP
Risk Management Quality Control

OCCUPATIONAL HYGIENE PROGRAMME

RISK ASSESSMENT AND CONTROL

DESCRIPTION OF RISK ASSESSMENT PROCESS
Management is committed to the safety and health to all employees and this Occupational Health programme will improve the system of monitoring occupational hazards, which was identified in the Occupational Health Risk Assessment. See updated risk assessment report for Occupational Health October 2010.

Identify all possible hazards by making use of:
a) International standard measuring methods, NIOSH.
b) Analyses by an accredited Laboratory.
c) ICP scanning.
d) Material safety data sheets (MSDS) for hazardous chemicals.
e) Identify all possible sources of airborne pollutants by making use of occupational hygiene techniques and professional judgement.

Quantify personal exposure to pollutants by:
a) Acceptable monitoring methods. (OESSM)
b) Making use of historical data available on measurements and analysis where applicable.
c) Determine what levels are people exposed to and the duration of exposure.

Recognise the risk by:
a) Consider all routes of entry. (The more routes of entry the higher the risk)
b) Consider synergistic health effects by different pollutants.
c) Making use of latest research information on health effects and OEL’s.
d) Making use of historical data available on health incidents reported at the occupational clinic.
e) Compare occupational exposure measurements with biological (BEI) monitoring results especially when more than one route of entry is involved.

• To monitor risks that persons may be exposed to and to eliminate, control or mitigate, and so far as the risk remains provide persons with correct protective equipment until the problem could be resolved;
• This assessment must be reviewed when processes change or new systems or chemicals are introduced;
• Periodically review the hazards identified and risks assessed, including the results of occupational hygiene measurements and medical surveillance, to determine whether further elimination, control and minimization of risk are necessary.

DETERMINATION OF HEGs (HOMOGENOUS EXPOSURE GROUPS)

IDENTIFICATION OF HEGs.

The mine has been sub divided into 3 sampling areas, viz:
– Sampling Area 1 Underground
– Sampling Area 2 Metallurgical Plant
– Sampling Area 3 Surface

a) Sampling Area 1 Activity areas are as follows: -8: 9: 13: 15; 17 and 18
b) Sampling Area 2 Activity areas are as follows:- 20; 21; 22; 24; 27; 26;30; 31; 33; 34
c) Sampling Area 3 Activity areas : 33; 31:34
d) Non Risk: Admin, stores, security, medical staff, surface training, change house, lamprooms, compressor attendants.< 10%
e) HEG classifications are based on the most significant risk, which are Alpha quartz (OEL 0.1mg/m3) & DPM OEL 0.35 mg/m3

Arsenic (As) OEL 0.1mg/m3 (D) Category.

These Results are updated on a running average of the latest 3 analysis and the alpha quartz concentration will change as per these results.
Other Pollutants analysed and assessed.

All other pollutants identified as insignificant will be monitored as PNOC as described in the OH risk assessment.

NIOSH method No 7300 is used to prepare filters for metals. The following pollutants will be measured and assessed at a regular basis.
1. Cadmium (Cd) Below detection limit
2. Cobalt (Co) Below detection limit
3. Cyanide Below 50% of OEL (CIL and Elusion Plant)
4. Inorganic Acid Below 50% of OEL (Elusion Plant, Electro winning process, biox plant,)
5. Welding Fumes 10-50% of OEL
6. VOC’s Plant floatation reagents below 50% of the OEL
7. PAH’s <50% OEL (Diesel exhaust fumes)
8. Diesel particulate matter. (DPM)
9. SO2, CO, NO2 NH3 <50% OEL (Smelter, Electro winning cell, Underground Blasting and diesel exhaust, welding)
10. Radiation Below detection levels.

Classification bands.
Airborne Pollutants.

Sketch indicating HEGs.
Mine plans.

90th Percentile.
The 90th percentile will be used for reclassification of HEGs once sufficient sampling data has been obtained.

Reassessment of HEGs.
The following criteria will be used to reassess HEGs: –
a) Exposure levels change due to control measures being initiated or when deteriorated;
b) Employee complaints received;
c) Changes in processes;
d) Medical Surveillance and Occupational illnesses indicate the need;
e) Changes in exposure categories;
f) New technologies or legislation requirements.

PERSONAL EXPOSURE MONITORING

Representative sampling of full working shifts.
a) The sampling schedule must be compiled allowing for random sampling to cover all shifts, different employees and different days over the monitoring period.
b) Sampling results of individual employees in a HEG will be allocated to all employees in that HEG by the medical staff on employee medical records.

Additional Sampling
a) Additional sampling will be carried out on a regular basis to ascertain the effectiveness of engineering controls; to identify sources, and to verify pollutant concentrations.
b) Sampling of welding fumes of welders.
c) Additional sampling will be carried out for any risk assessment or analyses required to increase confidence levels.
d) Wood dust at the carpenter workshop.
e) Arsenic at the arsenic store.

SAMPLING, ANALYSIS METHODOLOGY AND QUALITY CONTROL

SAMPLING STRATEGY FOR SILICA DUST.

Sampling Strategy for DPM

SAMPLING METHODOLOGY

Personal Gravimetric Sampling Strategy.
Employees to be sampled will be selected statistically from each HEG.
All relevant detail of all employees sampled wi

Personal gravimetric dust samples will be taken with the sampling trains running continuously for the full working shift.
Samples will be taken as per the sampling schedule, regardless of the prevailing weather conditions.

The volume flow of the sampling pump must be calibrated with a Gilibrator or calibrated Rotameter before the sampling train is put onto the employee to be sampled.

At the end of each sampling shift the volume flow of each sampling train will be checked, using the same method as for setting the flow rate prior to sampling. Only samples from sampling trains, which have a volume flow rate within the acceptable margin of ± 5 % of the calibrated, flow rate, will be accepted.
Intrinsically safe self-compensating gravimetric sampling pumps will be used.
The sampling pumps will be calibrated, with the sampling heads in line, at 2.2 litres per minute.

37/25mm Diameter G-X sampling cassettes (sampling heads) with G-X cyclones, and for total dust and fumes, without cyclones loaded with 25/37mm diameter, 0.8 micrometer pore size pre – weighted cellulose ester filters will complete the sampling trains.
Inhalable particulate. Total samples in identified HEGs (samples heads without cyclones)

Records of all relevant sampling and analyses information must be kept for a period of at least 2 (two) years.

ANALYSES METHODOLOGY
Weighing of filters will be done on a five-decimal point (g) analytical microbalance.
Filters required for sampling must be marked according to the HEG and Area to be sampled and recorded in a register for quality control purposes. These filters must be acclimatised for at least 24-hours before pre-weighing.

In all cases filters must be pre and post weighed against reference filters from the same batch of filters.
After sampling, filters will be acclimatised again for at least 24-hours before post weighing. The mass of the airborne particulate collected will be ascertained. The filters will be sent to an Accredited Laboratory for chemical analyses to determine the pollutant concentration in the sample.

Weighing of filters will take place under controlled conditions in a dedicated weighing facility.
Samples to and from the weighing facility will be transported “right-side up”, in a vertical position, in a suitably marked sample box fitted with a handle and lined with high density foam to minimise any particulate loss resulting from bumping or vibration. The sample box will be equipped with a suitable locking mechanism to prevent inadvertent opening of the sampling box.

Fumes
Fumes are micro particulate matter and are sampled in the same way as other particulates with a total particulate sampling head.

Vapours
Certain HCS are generally in the liquid state at ambient temperatures. At increased temperatures HCS could convert into a gaseous state and will be sampled as gases.

Gases
Spot sampling of the working environment will be carried out by means of direct reading instruments where toxic gases may accumulate. Personal sampling of these gases will be conducted using VOC-badges, Dosi-tubes, depending on the gas to be monitored.Analysis must be done by a laboratory using national or inter national accepted standards.

E.g. NIOSH methods. Test House (SANS) and Gas Chrom Analytical Services and CSIR are being used.

REPORTING AND RECORDING
Activity area assessment records and reports.
Records of all relevant sampling and analyses information must be kept for a period of at least five years.

Deviations of sampling results must be recorded indicating reasons for the deviation e.g. failure of controls, high winds, rain, wearer not employed at correct working activity etc. (App 2. f/sheet)
Partial supervisors must ensure that the sampling effort is carried out efficiently and that all relevant information is recorded.

The partial supervisor must visit the wearer at least twice during the sampling shift to ensure that the sampling train is functioning effectively.
During this visit the partial supervisor must ensure that relevant PPE is worn and record his findings on the field sheet at the end of the sampling shift.

Monthly reports to the relevant managers must include results of sampling during the month with relevant information and recommendations where applicable.

OCCUPATIONAL MEDICAL SURVEILLANCE

Health Care Information:
– All risk related tasks have standard working procedures;
– These standard working procedures are reviewed regularly;
– All Employees are issued with relevant approved PPE for the task they have to perform.
– Employees are trained in the correct use, maintenance and limitations of PPE during training and periodically thereafter.
– Employees are provided with PPE.
– Health and safety committees have been established;
– The Drafting Committees are actively involved in their legally prescribed functions.
– Employees who are holders of First Aid Certificates are responsible for first aid treatment in the working place using the allocated first aid boxes.
– A qualified Occupational Health Nurse and assistants are employed full time.
– The mine has an equipped occupational Health centre.
– An Occupational Medical Practitioner is employed part time
– The surveillance for occupational health is risk based and is detailed in the Mines medical surveillance programme.

OCCUPATIONAL MEDICAL SURVEILLANCE PROGRAM

– Chapter 11 of the MHSA Regulations and Section 13 of the MHSA requirements re Occupational Medical Surveillance
– Occupational medical surveillance will be done on site at the occupational health clinic. Staff conducting medical examination will be competent in terms of the requirements of the MHSA.
– Records will be kept in a medically confidential fashion at the mine and computerised records will have appropriate access controls. These may be made available only in accordance with the ethics of medical practice, or if required by law or court order, or if the employee has in writing consented to the release of the information (section 15 of the MHSA)
– Employees are entitled to copies of, or copies or copies of parts of, medical surveillance records or records of occupational hygiene measurements that relate to themselves (section 19 of the MHSA)
– All reasonable steps will be taken to ensure that records of medical surveillance will be stored safely and not be destroyed or disposed of for 40 years from the last date of medical surveillance of an employee, as prescribed by the MHSA (sections 15(2) and 13(8))
– Medical surveillance procedures will be transparent and open to discussion with all role-players. Endeavours will be made to conduct these professionally, scientifically based on best reasonable current medical practice.

Linkage between occupational hygiene and medical surveillance.
– Occupational Hygiene results are used by the Occupational Hygienist to categorise the exposure HEGs and the HEG averages are summarised in a risk Matrix annually from where the Medical Practitioner are able to do the medical surveillance.

– Employees’ exposure to pollutants will be linked to the medical record of employees by means of the electronic system. Data will be transferred manually into the system from where the Occupational Health Practitioner can be able to retrieve exposure profile and history.

Categories of medical examinations at which medical surveillance must be carried out.

A procedure describing how the following examinations will be conducted:
(a) Initial Examination.
Will be done pre-employment. The OMP will conduct initial examination and baseline tests, appropriate to the health hazards and pollutants of the envisaged occupation. The above examination will include clinical examination, X-ray, lung function, audiometric tests and relevant random biological monitoring if indicated by risk based health risk assessment.
(b) Periodic Examination.
The OMP will ensure that serving employees are examined at intervals appropriate to:

– The health hazards they are exposed to:
– The inherent requirements of their specific occupation
– The results of any relevant risk assessments
– The above examination will include X Ray and Lung Function Tests

(c) Exit examination.

– The examination must be held within 14 days of the termination of employment.
– The OMP who conducts the examination will produce an exit certificate indicating the results of all the medical surveillance that the employee has undergone and whether or not the employee has any occupational disease or health disorder. The copy of the exit certificate will be entered into the record of the employee’s surveillance. The OMP will supply the employee with a copy of the exit certificate.
– The above examination will include X Ray, Lung Function and Audiometric Tests.

METHODOLOGICAL STANDARDS FOR TEST TECHNIQUES FORMING PART OF MEDICAL SURVEILLANCE

The employer will ensure that large film chest x-rays will be of suitable quality for proper classification of Pneumoconiosis. (ILO 1980 should be consulted).
Show the date, name of individual and any unique form of personal identification.

Lung function testing – refer to the MOHAC Guidance Note for OMP on lung function testing.

FVC, FEV1, and the FEV1/FVC ratio should be indicated

MEDICAL SURVEILLANCE ACCORDING TO HEALTH HAZARD

Medical surveillance for each hazard will be done in parallel. The same examination or test will be used for medical surveillance of more than one hazard.
Risk based medical surveillance (RBMS) Risk Matrix.
The medical surveillance is based on a Risk Matrix.

All the Occupational Hygiene results are rated on a matrix according to the measurements and assessments made by the Appointed Occupational hygienist. This matrix is then forwarded to the Occupational Medical practitioner and he will then complete the matrix by determine the surveillance and pre-placement examination.

The Matrix Rating
Very High                                Category A                       Above OEL
High                                        Category B                      50% to 100%
Substantial Risk                      Category C                     10% to 50%
Tolerable Risk                         Category D                      < 10% and Short Term Exposures.
Potential Risk                          Very low exposure.

The following Table indicate the risk based medical surveillance programme. It will be updated on:
a) an annual base or
b) when there is a change in the process or
c) when there is any significant change in the hazard to which employees are exposed to.