n  Supplementary material

Title: Influences of artificial root exudate components on the behaviors of BDE-28 and BDE-47 in soils: desorption, availability and biodegradation

Journal name: Environmental Science and Pollution Research

Authors: Honglin Huang 1 · Sen Wang 1, 2 · Jitao Lv1 · Xuehui Xu 1 · Shuzhen Zhang 1

1 State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China[(]

2 Department of Environmental Sciences, College of Urban and Environmental Sciences, Northwest University, Xi’an 710027, China

*Shuzhen Zhang, .


Methods S1. Details on materials and methods used.

Extraction and analysis of PBDEs. Before extraction, 10 ng BDE-77 was added as surrogate standard to the samples. The final extracts containing PBDEs were concentrated to 200 µL under a stream of N2, and a known amount of internal standard (13C-PCB-141) was added. All steps were performed in opaque containers and samples were covered or refrigerated between steps to minimize exposure to light. An Agilent 7890 GC−EI−MS (5975 inert) (Agilent, Palo Alto, CA, USA) with a DB-5MS column (30 m × 0.32 mm × 0.25 µm) was used for PBDE analysis. All PBDE congeners were identified on the basis of their retention times. The carrier gas was helium at a flow rate of 1.5 mL/min. A 1 μL amount of the extracted sample was injected to the GC column. The temperature program was as follows: oven temperature held at 110 °C for 2 min, increased at 15 °C/min to 310 °C, and held for 15 min. Injector and detector temperatures were 300 °C and 320 °C, respectively. The two most intense ions of the [M-2Br]+ and the molecular ion fragments were monitored.

Quality assurance/quality control. Quality control was done by regular analyses of procedural blanks, blind duplicate samples, and random injection of solvent blanks and standards. The method detection limits (MDLs), defined as a signal of 3 times the noise level (n = 6), ranged from 6 to 20 pg/g for all the PBDE congeners. Recoveries of the surrogates of BDE-77 and 13C-PCB-141 were 80.3 ± 15 % and 90.6 ± 10 %. Recoveries of the 19 congeners ranged from 80.8 to 114.2 % with relative standard deviations < 10 % in three spiked blank samples (PBDE congeners spiked into anhydrous sodium sulfate) and from 73.4 to 121.3 % with relative standard deviations < 15 % in nine matrix spiked samples (PBDE congeners spiked into black and red soil samples, ultrapure water, which were free of PBDE contamination).

Table S1

The first order kinetics biodegradation rate constants and coefficients (R2) for BDE-28 and BDE-47 as affected by the application of root exudate components a.

Red soil / Black soil
BDE-28 / BDE-47 / BDE-28 / BDE-47
K (d-1) / R2 / K (d-1) / R2 / K (d-1) / R2 / K (d-1) / R2
Control / 0.018 ± 0.003 d / 0.95 / 0.036±0.008 b / 0.97 / 0.022±0.005 d / 0.98 / 0.051±0.008 b / 0.92
Glycine / 0.11±0.02 c / 0.95 / 0.10±0.02 a / 0.93 / 0.053±0.009 bc / 0.97 / 0.095±0.02 a / 0.94
Fructose / 0.30± 0.04 b / 0.97 / 0. 11±0.03 a / 0.91 / 0.076 ± 0.007 ab / 0.97 / 0.099±0.02 a / 0.97
Oxalic acid / 0.42± 0.07 a / 0.96 / 0.12±0.03 a / 0.87 / 0.087±0.01 a / 0.99 / 0.11±0.03 a / 0.97

a Means with the same letter are not significantly different at the 5 % level.

Fig. S1 PCR amplification of microbial DNA extracted from soils. (1) control, (2) oxalic acid, (3) glycine, (4) fructose (in BDE-28 spiked soils); (5) control, (6) oxalic acid, (7) glycine, (8) fructose (in BDE-47 spiked soils)


Fig. S2 Shannon index (A) and Cluster analysis (B) of microbial community in red soils and black soils from different treatments. Data represent mean ± SE, n = 3. Values with different letters are significantly different (p0.05)


Fig. S3 Debromination products of BDE-28 (A) and BDE-47 (B) in red soils and black soils after application of root exudate components and incubation for 60 d


Fig. S4 Effects of root exudates components (0—60 g/Kg) on soil−water partitioning coefficients (Kd=Csoil/Cwater, L/Kg) of BDE-28 and BDE-47


Fig. S5 Concentration of DOC in the soils when 20 g/Kg root exudate components were added with aging time of 60 d. Error bars represented standard errors. Means with the same letter are not significantly different at the 5 % level

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