Issues (Issue 35)

By on October 5, 2007

Silica Exposure

The CMPA recently located two studies on silicosis.

Quantitative Relations between Exposure to Respirable Quartz and Risk of Silicosis

The purpose of this study was to analyse exposure response data from to gain a more detailed knowledge of the relations between exposure to quartz and the risk of silicosis in miners.

Key messages from this article include:

  • In the epidemiology of mineral dusts, examine whether cumulative exposure is the best exposure matrix
  • Many alternative exposure matrix can be constructed with sufficient data. These can then be used to predict the risk of disease as variables (such as exposure levels, years exposed) change.
  • In data from coal miners who had unusual exposure to silica, exposure to higher concentrations was proportionally more risky than lower concentrations
  • Even quite short exposures to high concentrations can increase risk dramatically
  • Where possible, sites may wish to collect as much data about those exposed as possible in order for future statistical comparisons to be made. In this instance data relating to hours worked, exposures, and illness dated back to 1954 creating a good data set to work from.

An Old Threat in a New Setting: High Prevalence of Silicosis among Jewellery Workers

The purpose of this study was to investigate the risk of silicosis amongst workers in the jewellery trade, specifically those in central Italy who use chalk moulds in casting.

This was undertaken as a cross-sectional study involving 100 goldsmiths and consisted of a questionnaire and clinical examination. This job has a high exposure to silica in that the casting consisted of 70% quartz and cristobalite in the form of crystalline free silica which is then broken up into very small pieces.

Key messages from this article include:

  • Employers and employees need to have an understanding and appreciation of the risk and take appropriate measures (both in terms of hygiene and respiratory protection)
  • The high-resolution CT scan provided a more accurate diagnostic measure, however is not commonly used as the World Health Organisation indicated it is not a suitable tool because of its low availability, high costs and high exposure to radiation.
  • The very small silica particle size and the uncommonly high prevalence of free crystalline silica could play a crucial role in this instance
  • The duration of exposure was playing a crucial role in this instance

These articles demonstrate the need over time to collect data and maintain a regular monitoring schedule and also highlight the need to document when changes occur in exposure patterns (i.e. new equipment, changed systems of work etc.).

Work Plan Expectations by Community – Part 2 (cont. from Issue 34)

Lights

No external lighting other than that shown on the endorsed Work Plan without written consent.

Noise

  • Noise levels must comply to the State Environmental Protection Policy or noise levels published by the EPA
  • No external sound amplification equipment, loud speakers or sirens without further consent from the responsible authority
  • Variable levels for reversing horns, and located 1m from ground
  • Need to have acoustic evidence of impact upon surrounding community

Federal Environmental Issues

Federal Environment Protection and Biodiversity Conservation Act 1999 – Impact upon listed endangered species (in this instance Macquarie Perch, Trout Cod, Murray Cod, Growling Grass Frog in Seven Creek identified by Chris Blorik of Biosis).

Geological Evidence

  • Need for accurate information regarding resource life and quality
  • Method of reducing that life against the annual returns supplied to the DPI

Sustainable Land Management Practices

Demonstrate.

Future Buffers

Confi rm all existing overlays such as:

  • Erosion management overlay
  • Flood overlay

Traffic

  • Develop a Traffic Management Plan which meets the responsible authorities satisfaction
  • Copy must be on display at all times and be complied to
  • Suitable signage must be in place
  • Access must be of a standard to suit heavy haulage
  • Upgrade roads incorporating earth works, pavements, sealing, drainage, line marking and environmental treatment
  • Construct and seal road at all entry/ingress/egress points include the development and implementation of an environmental management plan
  • Identification of parking areas for customers and employees to be constructed to an engineer’s requirements
  • Measures to ensure no mud or other materials can migrate onto public roads
  • Provide evidence that the applicant/applicant’s contractor has Public Liability insurance of at least $110 million for duration of proposed road works
  • Comply to ‘Code of Practice for Work Site Safety – Traffic Management’, Road Safety Act, Road Management Act etc
  • Before commencing any road works develop an Environmental Management Plan
    • This must be approved by DSE as compliant to the native vegetation framework
    • This must also address matters such as weed, pathogens, stockpile sites, erosion and sediment control

Natural Landscape Protection

  • Protect areas of environmental and visual significance
  • Limit development on prominent ridges and hill tops
  • Encourage the protection and re-vegetation of landscape features as an enhancement
  • To contribute to the protection of the environmental equilibrium of hilltops and ridgelines
  • Ensure structures blend in with the surrounding environment
  • Ensure aesthetic amenity of the area is presented and/or enhanced

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