Spatial and temporal changes of polychlorinated biphenyls (PCBs) in the Bursa soils

Endüstriyel bir şehir olan Bursa'dan Haziran 2008 ile Haziran 2009 arasında yüzey toprak örnekleri (0-5 cm) 43 numune noktasından toplanmış ve 82 poliklorlu bifenil (PCB) türü için analiz edilmiştir. Dört bölge için tüm örnekleme noktalarındaki ortalama toplam PCB (Σ82PCBs) konsantrasyonu 2122±1188 pg/g kuru maddedir (KM) [Aralık 208-5462 pg/g KM]. Genelde, düşük klorlu PCB'ler baskın olarak belirlenmişlerdir (%79 seviyesinde ≤5 Cl gruplar). Bursa topraklarında baskın homolog grup olarak 5-CB'ler (%29) ve onu 4-CB'ler (%26) ve 3-CB'ler (%18) takip etmiştir. Dioksin-benzeri 7 PCB türü (PCB 77, 81, 105, 114, 118, 123, 126) her örnekleme noktasında bulunmuştur ve bunlar 7 ile 1580 pg/g KM arasında değişmiş olup ortalama 259±305 pg/g KM değerini almıştır. Dioksin-benzeri PCB ile ortalama toplam PCB'ler arasında önemli bir ilişki (r = 0.77, p < 0.01) bulunmuştur. Hafif türlerSurface soil (0-5 cm) samples from 43 sampling sites between June 2008 and April 2009 in Bursa, an industrialized city, were collected in each season and analyzed for 82 polychlorinated biphenyls (PCBs). The mean concentration of total PCBs (Σ82PCBs) among all sites over the four seasons was 2122±1188 pg/g dry weight (dw), with a range of 207.61 to 5,461.95 pg/g dw. In general, PCB patterns were dominated by low-chlorinated homologue groups (≤5 Cl groups at a 79% level). The predominant homologue group found in Bursa city soils was the penta-CBs (29%) followed by the tetra-CBs (26%) and tri-CBs (18%). A total of seven dioxin-like PCB congeners (CB-77, 81, 105, 114, 118, 123, and 126) were found in every sampling location and their mean total concentration for all locations and seasons was 259±305 pg/g dw, with a range of 7 to 1,580 pg/g dw. A significant relationship (r = 0.77, p < 0.01) was found between the concentrations of dioxin-like PCBs and the average sum of PCB concentrations. A correlation between light congeners (< penta-CB) and total organic carbon (TOC) was not observed, whereas a significant correlation (r = 0.36, p < 0.05) for heavy congeners (≤penta-CB) and TOC was found. The pollution potential was assessed based on the values found in soils in different regions in relation to current guideline values. Overall, it was found that PCB levels in the soils of Bursa were much lower than both the target values and the values found in most European soils and other regions.Recent studies have indicated that sewer systems and landfills contain PCBs. Eighteen surface soil samples were collected from five areas near wastewater treatment plants and landfills to investigate the PCB levels. The results show that the soils near treatment plants were not highly contaminated by PCBs.Forty soil samples were collected from 10 different sites to determine the levels of PCBs caused by traffic in the soil. Average PCBs ranged between 800 and 3350 pg/g dw in each site. Average PCB concentration for the sampling areas was found as 1800±1150 pg/g ds. A reasonable correlation between PCB levels and traffic was not determined