The EPA engaged Access Macquarie Limited (Macquarie University), Department of Environment and Geography, to conduct independent mercury ambient air monitoring at Orica’s Matraville premises in July 2014.
This was undertaken immediately prior to and during the initial stages of removing the Temporary Emissions Control Enclosure to verify the low level results that Orica has recorded during its monitoring, which is required under the company’s Environment Protection Licence.
Macquarie University carried out monitoring for one 24-hour period and one 48-hour period over
15-18 July near the enclosure, which is located on the site of Orica’s former chlor alkali plant at Botany Industrial Park (BIP).
Summary of results
The results show very small concentrations of mercury, which are significantly below the World Health Organisation (WHO) recommendation of an estimated tolerable concentration of 0.2µg/m3 (micrograms per cubic metre) for long-term inhalation exposure to elemental mercury vapour. Macquarie University’s results were measured in nanograms per cubic metre (ng/m3, that is one thousand times smaller), with the highest recording over the 3 days being 59.473ng/m3, or 0.059µg/m3. This is significantly less than the WHO level. The results were comparable to the levels recorded by Orica’s equipment at the boundary of BIP (see NSW Health website for Mercury and Health information).
Table 1 shows the mercury ambient air levels recorded for the 24-hour period from 10am 15 July to 10am 16 July, during which time the enclosure remained intact and the emission control systems were operational.
Table 1 Mercury ambient air levels recorded for the 24-hour period 15-16 July 2014 (values are measured as nanograms per cubic metre, ng/m3)
| Overall site average during sampling period | 4.100 ng/m3 |
| Maximum recorded value | 30.960 ng/m3 |
| Minimum recorded value | 0.795 ng/m3 |
| WHO recommendation | 200 ng/m3 |
Table 2 shows the mercury ambient air levels recorded for the 48-hour period from 10am 16 July to 10am 18 July, during which time the enclosure was progressively dismantled and the emission control systems were switched off (11:15am on 16 July).
Table 2 Mercury ambient air levels recorded for the 48-hour period 16-18 July 2014 (values are measured as nanograms per cubic metre, ng/m3)
| Overall site average during sampling period | 12.587 ng/m3 |
| Maximum recorded value | 59.473 ng/m3 |
| Minimum recorded value | 0.843 ng/m3 |
| WHO recommendation | 200 ng/m3 |
For a copy of the full report, please email your request to info.botany@epa.nsw.gov.au