## 3 Results and Discussion  
### THg in Mine Waste Calcines and Honda Bay Wharf  
From all the surface sediments collected in the vicinity of the abandoned mining site, there are two noticeable hotspots of very high Hg concentration relative to their surroundings (Figure 3). These are the mine waste calcines near the pit lake, and the calcine used in the construction of Honda Bay wharf.  
Mine waste calcines were found to be stocked northeast of the abandoned open pit lake (Figure 2). The mine waste calcines have poor sorting, angular grains, and can reach around 6 to 8 m in thickness. The calcine exhibits a reddish to orangey brown color due to the weathered iron bearing minerals and residual cinnabar. It mostly contains crushed bedrock material hosting the Hg deposit, along with few grains of silica from the opalite, which brought on the mineralization.  
In this study, the measured THg in mine waste calcines have concentrations ranging from 52.7-924.2 mg kg\({}^{-1}\). These calcines were stocked at the shore of the lake and scattered up to 500 m northeast of the lake. Total Hg concentrations found in the mine waste calcines are largely similar to the concentrations measured in the same study area in 2002-2003, but this time, a higher concentration (924.2 mg kg\({}^{-1}\)) was measured at one sampling point. A possible cause of the high THg concentration in mine waste calcines, is the inefficient and incomplete calcination or roasting of cinnabar ones. The range of THg concentrations in mine waste calcines measured in this study were generally within the range of THg concentrations on calcines from China, New Zealand, and the USA, as presented in Table 1.  
Total Hg concentrations measured in soil of Honda Bay wharf and stockpiled mine wastes exhibit similar ranges of concentration. Samples collected in Honda Bay wharf display the same physical characteristics as the calcines stockpiled near the pit lake. This confirms that the soil materials used in the construction of the wharf were the mine waste calcines from PQMI mine site. High THg concentration (731.6 mg kg\({}^{-1}\)) was also measured in the calcines stocked near the wharf. It was higher than the estimated THg concentration (570 mg kg\({}^{-1}\)) of all the calcine materials used in Honda Bay wharf in 1996 [24]. Sediment samples collected 10 m north of the wharf shore have Hg concentrations  
Figure 3: Map showing the total Hg concentration in soils and sediments in the study area.  
of \(>\)100 mg kg\({}^{-1}\), which is in agreement with the concentration reported by [PERSON] and co-workers [24] in 1996. As stated in previous studies [20,21,24], Honda Bay wharf is considered one of the possible sources of Hg contamination in Honda Bay. The removal of Honda Bay wharf as well as the dredging of contaminated tailings and sediments in Honda Bay, were suggested in the study of [PERSON] and co-workers in 1996 [21], but these recommendations were not followed. Today, the inhabitants of the villages located in the vicinity of the abandoned mine area including Honda Bay, which is home to around 10,000 inhabitants, are exposed to potentially serious health issues due to Hg contamination.