Atmospheric mercury in the Latrobe Valley, Australia: Case study June 2013

摘要

Gaseous elemental mercury observations were conducted at Churchill,Victoria, in Australia from April to July,2013, using a Tekran 2537 analyzer. A strong diurnal variation with daytime average values of 1.2–1.3 ng m–3and nighttime average values of 1.6–1.8 ng m–3 was observed. These values are significantly higher than theSouthern Hemisphere average of 0.85–1.05 ng m–3. Churchill is in the Latrobe Valley, approximately 150 kmEast of Melbourne, where approximately 80% of Victoria’s electricity is generated from low-rank brown coalfrom four major power stations: Loy Yang A, Loy Yang B, Hazelwood, and Yallourn. These aging generators donot have any sulfur, nitrogen oxide, or mercury air pollution controls. Mercury emitted in the 2015–2016 yearin the Latrobe Valley is estimated to have had an externalized health cost of $AUD88 million. Air pollutionmercury simulations were conducted using the Weather Research and Forecast model with Chemistry at 3 3km resolution. Electrical power generation emissions were added using mercury emissions created from theNational Energy Market’s 5-min energy distribution data.The strong diurnal cycle in the observed mercury waswell simulated (R2 ? .49 and P value ? 0.00) when soil mercury emissions arising from several years of wet anddry deposition in a radius around the power generators was included in the model, as has been observed aroundaging lignite coal power generators elsewhere. These results indicate that long-term air and soil sampling inpower generation regions, even after the closure of coal fired power stations, will have importantimplications to understanding the airborne mercury emissions sources.