**2.9 Estimation of atmospheric discharge of gaseous pollutants from the Kraft paper mill**

Previous studies have indicated that atmospheric deposition is a major source of most PTEs entering agricultural land [44, 45]. Thus, emission (E) estimates of selected gases, particulates, ash and chemical elements were calculated using emission factors (Ef) from literature [31, 46]. The equation used was E ¼ AixEf, where Ai = Activity or industrial production of the paper mill. The maximum production was 300 metric tonnes per day or 105,000 metric tonnes per year air-dried unbleached pulp. The study assumed that Kraft pulping was the only system at the mill and that the emissions came solely from the recovery boiler at the factory. In addition, we assumed that only an electrostatic precipitator was used to treat flue gases from the mill.

#### **2.10 Data analysis**

Statistical analyses were performed using STATISTICA 6.0 [47]. Data collected were first tested for homoscedasticity [48] before subjecting them to statistical analysis. Data on PTEs in water, soils and sediments were calculated as means (� S.D) for each site. Spatial differences in metal concentrations were analyzed using One-way ANOVA. Duncan's Multiple Range Tests (DMRT) were used for Post-hoc discrimination between the means that differed significantly. The data for all the sites were subjected to Principal Component Analysis (PCA) to determine the correlation between the PTEs concentration in soil, water and sediments and their proximity to the Kraft mill [49].
