Polychlorinated naphthalene (PCN) emissions from scrap processing steel plants with electric-arc furnaces

Abstract Polychlorinated naphthalene (PCN) emissions of scrap iron processing steel plants were explored by measuring concentrations in stack gases of five plants, in the atmosphere (n = 11) at a site close to those plants, and in soil at several sites in the region (n = 40) in Aliaga, Izmir, Turkey. Observed stack-gas Σ 32 PCN levels from the plants without scrap preheating (189 ± 157 ng Nm − 3 , average ± SD, n = 4) showed that they are substantial PCN emitting sources. Stack-gas Σ 32 PCN level for the plant with scrap preheating was considerably higher (1262 ng Nm − 3 ). Similarly, Σ 32 PCN emission factor for this plant was substantially higher (11.9 mg ton − 1 ) compared to those without scrap preheating (1.30 ± 0.98 mg ton − 1 ). Results have also suggested that the investigated steel plants emit large quantities of fugitive particle-phase PCNs. Measured soil Σ 32 PCN concentrations that are considered to be representative of the atmospheric levels were greatly variable in the region, ranging between 0.003 and 10.02 μg kg − 1 (dry wt). Their spatial distribution showed that main PCN sources in the region were the iron-steel plants. Ambient air levels (1620 ± 800 pg m − 3 ) were substantially higher than ones observed around the world and in the study area verifying that the steel plants with electric arc furnaces (EAFs) are important PCN sources. Investigation of possible mechanisms suggested that the combustion processes also contribute to emissions from EAFs in addition to evaporation of PCNs present in the scrap iron.