Combination of a fast cleanup procedure and a DR-CALUX® bioassay for dioxin surveillance in Taiwanese soils

• Published in: International journal of environmental research and public health 2014-05, Vol.11 (5), p.4886-4904
• Main Authors: Lin, Ding-Yan, Lee, Yi-Pin, Li, Chiu-Ping, Chi, Kai-Hsien, Liang, Bo-Wei P, Liu, Wen-Yao, Wang, Chih-Cheng, Lin, Susana, Chen, Ting-Chien, Yeh, Kuei-Jyum C, Hsu, Ping-Chi, Hsu, Yi-Chyun, Chao, How-Ran, Tsou, Tsui-Chun
• Format: Article
• Language: English
• Subjects: Biological Assay; Dioxins - analysis; Environmental Monitoring - methods; Environmental Restoration and Remediation; Gas Chromatography-Mass Spectrometry; Multivariate Analysis; Soil - chemistry; Soil Pollutants - analysis; Taiwan
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph110504886

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R2 = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.