## 2 Materials and Methods
### Chemicals and Analytical Methods  
The AMA-254 apparatus was used to measure the mercury content in soils and absorbed on gold-platinum sensors. The device operates within a temperature range of 0 to 35 \({}^{\circ}\)C and a maximum relative humidity of 80%. The carrier gas is oxygen at an input pressure of 200-250 kPa. The mercury measurements are taken at a wavelength of 253.65 nm. The instrument has two measurement ranges: Range I covers concentrations from 0.05 to 40 ng of Hg/sample, while Range II measures from 50 to 600 ng of Hg/sample. To ensure measurement quality, certified reference materials (CRM BCR(r)-320R produced by IRMM and Mercury Standard Solution 1000 mg Hg/L (Certipur CRM Merck)) were used in atomic absorption spectroscopy (AAS) with the AMA-254. The operating conditions of the device during the mercury measurements in soil and absorbed on gold sensors are summarized in Table 3[40]. Soil samples taken from hydrocarbon exploration and exploitation sites were analyzed in a laboratory to determine both the total mercury content in the soil and the mercury content that could be emitted. Measurements of the total mercury content in soil were carried out with the use of the mercury analyzer AMA-254, a method that utilizes atomic absorption. The measurements were conducted with an accredited method, as recommended by Polish law for determining the total mercury content in soil. Measurements of the content of metallic mercury (Hg\({}^{0}\)), which can be emitted from the soil, were carried out using a proprietary method based on the correlation between mercury emissions to the air and the content of metallic mercury in soil. This method involves measuring the mercury emissions from a given amount of soil under strictly defined and controlled conditions (temperature, sorption time, volume of the measuring vessel, and size of the gold element), as determined during the validation of the method. A summary of the key parameters for measuring emissions-capable mercury using the author's method with a gold sensor in a flask is presented in Table 4.  
The assessment of the distribution of mercury contamination was also conducted in the field based on the results of the emissions measurements from the studied area. Emissions measurements were performed using diffusion chambers and passive sensors of our own design, where the emitted mercury was sorbed onto gold elements. The mercury content was then measured in a laboratory using the mercury analyzer AMA-254. The results of the mercury emissions were evaluated using a proprietary algorithm, which was based on the emissions levels determined for areas free of metallic mercury contamination and the values determined for areas contaminated with metallic mercury. The emissions rate E (in ng/h/m\({}^{2}\)) was calculated by dividing the mass of absorbed mercury m (in ng) by the area of soil covered by the chamber (A) or passive sensor and the measurement duration (t--time in hours). \[\mathrm{E}=\frac{\mathrm{m}}{\mathrm{A}\ast\mathrm{t}}\]  
where  
E--determined the mercury emission rate, [ng/m\({}^{2}\)/h]. m--is the mass of the mercury adsorbed on the sensor during measurement, [ng]. A--is the area of soil covered by the diffusion chamber and or passive sampler (in the case of chambers during the present work, A = 0.1963 m\({}^{2}\)), [m\({}^{2}\)]. t--is the time of the conducted measurement of Hg emissions expressed in hours, [h]. An evaluation of the emissions rate (the obtained results of the mercury content sorbed on the gold sensor) was converted to an emissions rate value [ng Hg/h/m\({}^{2}\)] and compared with the experimentally determined limit value for the areas not contaminated with mercury. The determined limit value for the emissions rate of mercury for the areas not contaminated with metallic mercury is 100 ng Hg/h/m\({}^{2}\). If the determined emissions value for mercury is greater than the limit value, the area under investigation should be considered as potentially contaminated with metallic mercury capable of being emitted.