CDC/NIOSH visiting team submits findings to PAHO/WHO

Mercury exposure

Following a request made to the Pan American Health Organisation/World Health Organisation representative’s office in Guyana by the Natural Resources Minister for further technical support, the United States Department of Health and Human Services of the Centres for Disease Control and Prevention has submitted a preliminary summary of their findings and recommendations following a visit to Guyana from September 11-14, 2018.
The visit was facilitated through ongoing collaboration with the PAHO/WHO Guyana Country Office and the National Institute for Occupational Safety and Health (NIOSH) following reports of concerns raised earlier in the year about overexposure to mercury emissions.
The team consisted of two engineers: Duane R Hammond MS, PE; and Kevin H Dunn ScD; CIH from the Engineering and Physical Hazards Branch, Division of Field Studies and Engineering.
During the visit, the team met with Ministers Trotman, Lawrence, and Scott, as well as representatives from the Guyana Gold Board and local PAHO/WHO representatives. Dr Dunn and Captain Hammond observed gold burning and smelting operations at the Guyana Gold Board’s temporary location on Crown Street. They also spoke with employees and managers, as well as the contractor. The team used a top-of-the-line and highly recognised reading instrument to evaluate mercury vapour concentrations throughout the Guyana Geology and Mines complex, the Public Health Ministry’s complex, the Guyana Telephone and Telegraph Company and the Guyana Gold Board’s burning and smelting rooms, and in surrounding offices and outer areas.
The team said that almost all of the readings taken throughout the GGMC, MoPH and GTT compounds were below the analytical limit of detection. They confirmed also that while a few areas had detectable results, no area exceeded the lowest applicable eight-hour time weighted average occupational exposure limit of 0.025 mg/m3. In other words, what is considered safe and acceptable.
With specific respect to the GGB (Crown Street), the report stated, “We collected 80 direct reading measurements for mercury [vapour] in the burning room during and after burns (six burns total) at the GGB. We found none of the reading measurements were above the NIOSH ceiling limit of 0.1 mg/m3 [NIOSH 2018].” The team of experts defined a ceiling limit in the report as, “a level that should never be exceeded at any time during a shift.” Very specifically, the report noted that, “Measurement results ranged from 0.000-0.041 mg/m3.” Again, safe and healthy, which bring much comfort.
Among the team’s recommendations were that the GGB: 1) install an air velocity monitoring device; 2) monitor mercury vapour concentrations in the burn room and waiting areas during burning on a daily basis; 3) develop standard operating procedures to incorporate mercury monitoring as part of the daily systems evaluation; 4) ensure adherence to procedures; and 5) maintain the facilities following a strict regime of oversight.