1
Supporting Information
Spatial Distribution of Hexachlorocyclohexanes in Agricultural Soils in Zhejiang
Province, China and Correlations with Elevation and Temperature
ANPING ZHANG,† WEIPING LIU,†,‡*HEJIN YUAN,† SHANSHAN ZHOU,† YUSHAN SU,§ AND YI-FAN LI§,†,＃*
†
International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), Zhejiang University of Technology, Hangzhou 310032, China
‡
MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
§
Science and Technology Branch, Environment Canada, Toronto, Ontario M3H5T4, Canada
＃ IJRC-PTS, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of
Technology, Harbin 150090, China
*
Corresponding author:
Weiping Liu and Yi-fan Li
Tel.: +86-571-8832-0666. Fax: +86-571-8832-0884. E-mail address: [email protected] and
†
Zhejiang University of Technology
‡
Zhejiang University
§
Environment Canada
Contents
TEXT SI-1. Materials and Methods 3
TEXT SI-2. Determination of soil properties 9
TABLE SI-1. Selected physicochemical and microbial parameters of 58 soils 11 TABLE SI-2. Residues of HCH isomers (ng/g) and isomeric ratio in soils 14 TABLE SI-3. Concentration of HCHs (ng/g) in soils from different areas of China 17 TABLE SI-4. Vertical distribution of HCH isomers (ng/g) in soils at selected sites 18 TABLE SI-5. Enantiomeric fractions (EFs) of α-HCH in soils 20 TABLE SI-6. Correlation between soil properties and enantiomeric characteristic
of α-HCH
21
FIGURE SI-1. Gridded total usage of technical HCH from 1952 to 1984 with 1/6
latitude by 1/4 longitude resolution (around 24 by 24 km). The total usage was approximately 100 kt.
22
FIGURE SI-2. Locations of 58 sampling sites. 23
FIGURE SI-3. Gridded elevation with 1/6 latitude by 1/4 longitude resolution
(around 24 by 24 km).
24
FIGURE SI-4. Temperature in Zhejiang province for 2007 25 FIGURE SI-5. Gridded Temperature in Zhejiang province for 2007 with 1/6º
latitude by 1/4º longitude resolution (around 24 by 24 km).
26
FIGURE SI-6. Vertical profiles of total HCHs residues in different layers for the 5
sampling sites.
27
FIGURE SI-7. The chromatograms of CD and ORD of resolved enantiomers
27
3
TEXT SI-1. Materials and Methods
Materials
All racemic OCPs analytical standards were purchased from Dr. Ehrenstorfer GmbH, Augsburg, Germany. All solvents used were of HPLC or glass-distilled grade. Anhydrous granular sodium sulfate was obtained from Hangzhou Huipu Co. Ltd. China, and baked at 400°C overnight before use. Other reagents were of analytical grade.
Sample Collection
Fifty eight soil samples were collected in agricultural soils in eleven prefecture-level divisions of Zhejiang province in 2006 and 2007(Table SI-1). At each site, overlying vegetation and other plant were removed prior to collection of the sample, and then composite bulk soil samples (0-20 cm) were collected from 8 cores using a hand-held coring device and pooled to obtain a representative sample for each field. Samples were placed in precleaned aluminum foil, sealed in plastic bags. After
transportation to the laboratory, soil samples were kept 4°C in a refrigerator till analysis. A portion of soil sample (~20g) at each sampling site was accurately measured, and was air-dried at room
temperature and ground to pass through a 60-mesh sieve were used to determine physicochemical characteristics, including the soil moisture contents by using a oven-frying method.
Extraction and Cleanup
A 20-g soil sample was extracted in a Soxhlet apparatus with dichloromethane (DCM) for 16h. The extract was concentrated into 100 mL by rotary evaporation, and initially cleaned up and
& Evaporation Processes System with a column (2.5 cm (i.d.)×40 cm) packed with Bio-Beads S-X3 of 200-400 mesh (GPC Ultra 10836, LCTech GmbH, Munich, Germany). The parameters used for the GPC purification were as follows,flow rate, 5.0 mL/min; column pre-clean time, 10 Sec; forerun, 1020 Sec; fraction, 1000 Sec; Tailing, 300 Sec; solvent exchange, 3 times. The solution from GPC was further reduced and solvent-exchanged to isooctane under a gentle stream of high-purity nitrogen to a final volume 1-2 mL. Samples were subsequently cleaned up using an aluminum/silica column containing 4 g of 3% deactivated silica gel topped with 2 g 6% deactivated aluminum. The column was subsequently eluted with 15 mL hexane, and 70 mL of hexane containing 30% (V/V) DCM. The first fraction of hexane effluent (about 10 mL) was discarded to minimize the amount of PCB
congeners and non-polar compounds in the extract. The rest of effluents containing the interested analytes were collected and the solvent was exchanged into isooctane under a gentle stream of high pure nitrogen, given further cleanup by shaking with 0.5 mL of 18M sulfuric acid, and adjusted to a suitable volume for analysis. A known quantity of pentachloronitrobenzene (PCNB) was added as an internal standard prior to gas chromatography electron capture detector (GC-ECD) analysis.
Analysis
Samples were quantitatively analyzed using an Agilent gas chromatograph 6890 equipped with a Nickel 63 electron capture detector (µECD) and a Zebron MultiResidue-1 column(30m, 0.25 mm i.d., 0.25µm film thickness; Phenomenex, USA). The samples were injected by 7683B autosampling in splitless mode (split opened after 1.0 min). The chromatographic conditions used for the column
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carrier gas, He at 3.4mL/min; makeup gas, N2 at 60 mL/min. Samples were quantified against 7
standards that spanned concentration range of the samples. Chromatographic data was collected and processed using Chemstation software of version A. 10. 02. The results were confirmed on the
secondary column HP-5 (30 m, 0.25 mm i.d., 0.25µm film thickness; Agilent Technologies Inc.). The temperature program was: temperature program, initial temperature of 80 °C, hold 1min, 10 °C/min to 200 °C, 1 °C /min to 225 °C, hold 1min, 15 °C /min to 260 °C, hold 5 min. Injector and detector temperatures were 250 and 300 °C, respectively. Judgements concerning residues in soil were based on whether the retention time (RT) of resides fell within or outside the mean RT ± 3 standard deviation (SD) for standards. Random samples with sufficient amount were injected into Agilent 7890 GC-5973 C Mass spectrometer with negative ion mass spectrometry and HP-5MS (30 m, 0.25 mm i.d., 0.25 µm film thickness; Agilent Technologies Inc.) for confirmation of the analysis accuracy of the above method.
The following equation was used to calculate the concentration (in ng/g dw (dry weight)) of HCHs in soil. %) 1 /( MC W V C C s f solvent solvent soil + × = where
Csoilis concentration of HCHs in soil,
Csolvent is concentration of HCHs in the final solvent and directly determined by GC,
Vsolvent is volume of the final solvent,
MC% is percentage of moisture content in soil.
The unit of Csolvent , Vsolvent, and Wfs are ng/mL, mL and g, respectively. So, it can be deduced that the
unit of Csoilis ng/g dw.
Enantiomer analysis was done by the above gas chromatographic instrument with chiral capillary column, and confirmed on an Agilent 7890 GC-5973 inert Mass spectrometer (negative ion mass spectrometry, NIMS) operated in the selected ion monitoring mode. Samples (2 µL) were injected splitless, and split was opened after 1.0 min. Chiral columns, BGB-172 column (20%
tert-butyldimethylsilylated-β-cyclodextrin in OV-1701, 30 m, 0.25 mm i.d., 0.25 µm film thickness; BGB Analytik AG), was used for emantiomer separation. The initial oven-temperature was set at 90 °C. After a 1-min hold, oven-temperature programs were used as follows: 15 °C /min to 160 °C, 1 °C/min to 190 °C, hold 35 min, 20 °C/min to 230 °C, hold 20 min. Helium was used as carrier gas at flow rate of 50 cm/s; injector and transfer line temperatures were set at 250 °C. The temperature of ion source and quadrupole was 150 °C. Methane pressure was 1.0 Torr. The ions, m/z 254.8 and 256.8, were monitored for target as follows.
Results were expressed as the enantiomer fraction (EF), EF is defined as the ratio of peak area of the (+)-enantiomer to sum peak area of the (+) and (-) enantiomer eluting from the chiral column. EF is considered to be a better descriptor than the enantiomer ratio in describing chiral analysis of
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collected from the outlet of chiral JASCO LC-2000 series high performance liquid chromatography (HPLC) system (JASCO, Tokyo, Japan). The elution orders which were confirmed for α-HCH
enantiomers on BGB-172 with resolved enantiomer were (-) prior to (+).The results are agreement well with the elution orders reported for α-HCH.
Quality Control/Quality Assurance
All analytical procedures were carried out under the strict quality assurance and control measures to ensure data quality. Method blanks (solvent) were processed by extracting and analyzing 15 g of sodium sulfate using the same procedure as for samples. The “limit of quantification” (LOQ) was calculated by multiplying the final extract volume by the concentration of target compounds that could produce a chromatographic peak with signal/noise ratio of 10 and dividing by the dry weight of an average soil sample. Eight spike recovery experiments were done with soil where residues were close to or below the detection limit. Approximately 20 g of soil was spiked with the components of interest, analyzed as the same manner as for samples. After correcting for the native amounts in the soil, recoveries ranged from 80 to 94%. Surrogate standards of 2, 4, 5, 6-tetrachloro-m-xylene (TCmX) were added to all samples prior to extraction to check the procedural performance. The mean recoveries were 77 ± 11 % for TCmX. Reported residues of HCHs were not corrected by the recoveries of surrogate. A known quantity of pentachloronitrobenzene (PCNB) was added as an internal standard prior to gas chromatography electron capture detector (GC-ECD) analysis. A procedural blank was run with every set of 15 samples to check for the contamination from solvents and glassware. All samples were extracted and analyzed in triplicate. Random samples were
extraction. No target analytes were found in the second extraction.
The preparation of single-enantiomer of α-HCH
The chromatographic system consists of a PU-2089 quaternary gradient pump, a mobile phase vacuum degasser, an AS-2055 autosampler with a 100 µL loop, a CO-2060 column temperature control compartment, a variable-wavelength CD-2095 circular dichroism detector, an OR-2090 optical rotation detector (ORD), and an LC-Net II/ADC data collector. The conditions for chiral separation was as follows: column, Chiralcel OJ (0.46 cm (i.d.)×15 cm, Chiralcel, Daicel Chemical Industry. Ltd.), mobile phase, n-hexane/isopropanol (91/9, V/V), flow rate, 0.5 mL/min. The rotation sign (“+” or “-”) of enantiomer was indicated by a positive or negative peak on the chromatogram (Fig. SI-7). The enantiomer peaks can also be identified by the elution order determined in the previous work which found that (+)-enantiomer eluted firstly on Chiralcel OJ (1). The results were
identical with our observations. The resolved enantiomers were manually collected at the HPLC outlet, and injected into an Agilent 6890 GC equipped with an Agilent 5975 C mass spectrometer for structural identification.
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TEXT SI-2. Determination of Soil Properties
The following physicochemical characteristics of samples were measured: soil pH values
(pH(KCl)), total organic carbon (TOC), clay (<0.002 mm), silt (0.002-0.05 mm), microbial biomass content (Cbio). Soil pH values were determined by the following procedure (2). Weighed 10 g of
air-dried and sieved (< 2 mm) soil was transferred into a plastic beaker, and then 25 ml of 1 mol/L KCl solution was added and stirred for 1 minute. The pH is measured by pH meter with appropriate electrode in the supernatant after 1 h of standing and a second short stirring. The method for
analyzing organic carbon content was as follow: air-dried and sieved soil was acidified by 10% HCl to remove carbonates, and then washed by distilled water to neutral. The organic carbon content was determined using an Elementar MAX CNS Analyzer (Elementar Analysensysteme GmbH.). A standard method was used to determine percentage of silt and clay in soil samples (3). In brief, soil-particle suspension was prepared by adding suitable dispersant, standing for 2h after shaking up, and boiling for 1 h. Soil slurry was sieved through nested standard 0.053-mm mesh sieves to separate sand particles after cooling. The solution, particles (silt and clay) passing the sieve and water used to wash sand were collected in a sedimentation cylinder. This solution was stirred thoroughly to achieve suspension of all soil particles and kept at constant temperature. The data of thermometer and soil densimeter in suspension were recorded at different time. The percentage of particles with different diameter was calculated according to reference (4). Microbial biomass content (Cbio) was measured
by chloroform-fumigation extraction methods as described by Wu (5). Water-saturated soil
equivalent to 35 g on an oven-dry basis was fumigated in desiccators under vacuum by ethanol-free chloroform. After incubation for 24 h in the dark at 25°C, the chloroform was absolutely removed by
repeated evacuation before soils were extracted with 140 ml of 0.5 mol/L K2SO4 solution. Control
soils were treated as the procedural for fumigated soils, except being free from chloroform. Soil extracts were stored in a freezer at –2 °C for several days. The suitable volume of sodium
hexametaphosphate solution was added into extracts prior to analyzing with a TOC-VCPH analyzer
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TABLE SI-1. Selected physicochemical and microbial parameters of 58 soil samples (15 mountain sites and 43 plain sites)
Sample Longitude Latitude Elevation (m) TOC (%) pH
Silt (0.05-0.002, %） Clay (＜0.002 %) Cbio (mg C/kg·dm) HUZ01 120°03´31.08˝ 30°46´05.01˝ 27.93 0.70 4.88 19 12 354.01 HUZ02 119°59´42.73˝ 30°39´08.16˝ 135.10 1.00 5.77 39 23 286.74 HUZ03 119°56´58.04˝ 30°59´28.01˝ 17.81 1.76 5.88 48 22 277.44 HUZ04 119°44´55.01˝ 31°08´02.05˝ 155.85 1.44 5.07 37 21 264.43 HUZ05 119°55´47.60˝ 30°23´03.13˝ 76.54 1.68 6.02 64 32 177.72 HUZ06 119°55´30.47˝ 30°22´28.77˝ 76.54 0.94 5.60 62 31 257.51 HUZ07 119°56´03.98˝ 30°26´57.56˝ 76.54 1.31 3.76 11 7 148.68 HZHZ01 120°13´25.49˝ 30°17´50.49˝ 46.19 1.40 4.87 75 24 419.43 HZHZ02 120°22´10.57˝ 30°09´29.96˝ 72.27 0.90 6.21 58 18 302.40 HZHZ03 120°12´10.02˝ 30°23´16.06˝ 46.19 0.70 5.64 19 13 220.53 HZ04 120°11´54.26˝ 30°23´54.34˝ 62.35 0.38 5.37 33 23 413.83
HZ05 120°13´19.19˝ 30°07´47.41˝ 72.27 1.23 5.31 23 15 51.28 HZ06 120°13´24.20˝ 30°17´48.06˝ 62.35 1.56 5.42 67 32 312.59 HZ07 120°22´59.80˝ 30°09´43.90˝ 371.73 2.47 5.71 21 13 184.29 HZ08 120°18´03 68˝ 30°06´31 06˝ 273.56 1.04 4.98 56 26 144.96 HZ09 120°19´34 88˝ 30°01´29 88˝ 46.19 3.01 5.68 29 14 400.81 HZ10 119°42´27 78˝ 29°39´09 84˝ 371.73 2.59 5.90 51 29 1210.58 HZ11 119°14´14.56˝ 29°20´32.87˝ 16.06 0.24 3.95 48 30 22.44 HZ12 120°09´29.50˝ 30°17´16.18˝ 16.06 2.64 6.81 18 8 709.36 JH01 119°35´22.59˝ 29°06´08.00˝ 64.50 1.30 5.69 36 24 173.80 JH02 119°48´14.10˝ 29°19´49.81˝ 70.25 1.29 5.64 44 20 403.96 JH03 120°27´27 60˝ 29°05´08.12˝ 352.25 2.33 6.38 43 18 849.02 JH04 120°20´11 00˝ 29°18´18.74˝ 230.53 1.21 5.42 11 6 967.52
13 JX01 120°57´40.60˝ 30°48´38.37˝ 7.83 1.39 6.00 67 32 389.97 JX02 120°41´58.61˝ 30°41´00.36˝ 5.69 0.69 5.15 71 20 38.13 JX03 120°55´18.19˝ 30°36´50.53˝ 7.19 1.00 5.60 65 29 226.67 JX04 120°51´42.62˝ 30°23´50.42˝ 7.19 1.62 5.10 21 10 282.09 JX05 120°51´42.46˝ 30°32´37.82˝ 5.21 0.76 6.25 33 14 263.15 JX06 120°47´05.09˝ 30°35´04.57˝ 5.21 2.03 5.17 69 27 333.22 JX07 120°37´32.02˝ 30°24´18.25˝ 8.46 1.08 5.04 66 28 225.91 JX08 120°37´27.11˝ 30°24´22.89˝ 7.07 1.01 5.06 27 17 423.25 JX09 120°45´56.24˝ 30°55´46.63˝ 1.70 1.19 6.91 63 21 153.88 JX10 120°22´50.77˝ 30°23´58.57˝ 8.47 1.29 5.43 70 27 225.61 JX11 121°08´45.76˝ 30°37´15.05˝ 7.19 1.07 4.12 28 17 131.52 LS01 119°02´15.78 28°03´58.53 460.14 1.34 6.30 77 22 484.58 LS02 119°00´32.02˝ 27°40´38.24˝ 966.30 0.24 4.91 32 20 19.44 NB01 121°30´58.98˝ 30°08´04.35˝ 40.06 1.35 7.07 69 1 242.21
NB02 121°10´19.04˝ 30°12´30.23˝ 5.48 1.47 5.91 37 16 844.31 NB03 121°11´51.64˝ 29°51´45.42˝ 245.00 1.11 7.25 70 30 250.93 NB04 121°42´13 34˝ 29°17´14.80˝ 21.36 1.09 3.80 11 9 46.99 NB05 121°11´07.06˝ 30°07´13.26˝ 39.12 0.13 3.90 36 27 4.28 QZ01 118°52´02.86˝ 29°03´39.08˝ 201.48 0.51 7.63 79 21 1102.40 QZ02 119°10´24.17˝ 29°03´32.95˝ 55.67 0.82 4.38 30 18 304.64 SX01 120°46´33.53˝ 29°23´31.85˝ 273.58 1.67 4.60 43 21 152.02 SX02 120°50´01.19˝ 29°28´09.02˝ 270.32 2.01 5.62 59 39 907.14 SX03 120°36´41.62˝ 29°58´05.88˝ 39.13 1.19 4.85 52 29 982.14 SX04 120°46´46.93˝ 30°09´35.28˝ 22.80 2.25 5.45 74 24 387.30 SX05 120°28´22.60˝ 29°50´39.83˝ 74.98 0.55 3.91 35 25 41.44 TZ01 121°03´30.57˝ 28°32´30.91˝ 153.08 1.41 5.45 32 18 383.70 TZ02 121°20´20.59˝ 28°31´27.31˝ 14.12 1.77 6.20 67 30 281.99
15 WZ01 120°32´02.84˝ 28°18´43.39˝ 296.00 1.71 5.35 34 19 238.02 WZ02 120°25´32.73˝ 27°53´55 65˝ 375.52 1.39 5.23 59 32 308.09 WZ03 120°29´24.94˝ 27°37´19.26˝ 129.70 0.55 4.05 19 14 32.04 ZS01 122°08´47.34˝ 30°18´18.88 2.11 1.79 5.86 62 23 570.57 ZS02 122°14´43.39˝ ,30°01´40.14˝ 60.38 0.63 4.00 25 11 25.52
TABLE SI-2. Residues of HCH isomers (ng/g) and isomeric ratio in soils sample α-HCH γ-HCH β-HCH δ-HCH HCHs α-HCH/β-HCH α-HCH/γ-HCH HZ01 0.95±0.18 BDL 0.99±0.18 BDL 1.94 0.96 >7 HZ02 0.91±0.18 BDL 0.73±0.26 BDL 1.65 1.25 >7 HZ03 1.24±0.02 BDL BDL BDL 1.24 - >7 HZ04 1.21±0.50 BDL BDL BDL 1.21 - >7 HZ05 0.84±0.11 0.79±0.13 1.00±0.42 BDL 2.62 0.84 1.06 HZ06 BDL 1.28±0.73 BDL BDL 1.28 0.50 0 HZ07 BDL BDL 1.38±0.35 BDL 1.38 0.01 - HZ08 6.77±0.66 4.50±0.09 BDL BDL 11.28 - 1.50 HZ09 2.99±0.77 3.23±0.02 4.15±0.05 BDL 10.37 0.72 0.93 HZ10 24.88±2.61 8.45±0.61 15.23±0.77 1.99±0.60 50.56 1.63 2.94 HZ11 1.26±0.074 1.18±0.16 1.84±0.10 2.11±0.12 6.39 0.68 1.07 HZ12 7.38±0.78 1.25±0.51 0.73±0.13 2.74±0.03 12.10 10.11 5.90 JX01 BDL BDL BDL BDL BDL - - JX02 BDL 0.85±0.10 1.04±0.64 BDL 1.90 0.01 0 JX03 BDL BDL 1.15±0.28 BDL 1.16 0.01 0 JX04 BDL BDL BDL BDL BDL - - JX05 BDL BDL BDL BDL BDL - - JX06 1.48±0.45 1.21±0.30 1.94±0.21 BDL 4.63 0.76 1.22 JX07 1.03±0.13 0.88±0.01 1.43±0.82 BDL 3.34 0.72 1.17
17 JX10 1.04±0.61 1.05±0.41 1.27±0.76 BDL 3.37 0.82 0.99 JX11 1.20±0.04 1.44±0.14 1.54±0.05 2.35±0.003 6.53 0.78 0.83 HUZ01 1.00±0.10 0.95±0.03 BDL BDL 1.95 - 1.05 HUZ02 BDL BDL BDL BDL BDL - - HUZ03 BDL 1.22±0.15 1.47±0.04 1.42±0.21 4.11 0.01 0 HUZ04 1.32±0.01 0.91±0.04 1.05±0.07 BDL 3.27 1.26 1.45 HUZ05 0.97±0.01 0.94±0.23 0.85±0.24 BDL 2.76 1.14 1.03 HUZ06 BDL 0.78±0.04 0.69±0.19 BDL 1.48 0.01 0 HUZ07 1.01±0.19 1.80±0.25 2.29±0.59 1.48±0.13 6.58 0.44 0.56 JH01 3.62±0.54 1.02±0.18 4.28±0.65 BDL 8.93 0.85 3.54 JH02 2.27±0.33 4.65±1.02 0.86±1.03 BDL 7.78 2.64 0.49 JH03 0.55 2.58±0.33 3.28±0.64 BDL 6.41 0.17 0.19 JH04 1.14±0.13 0.86±0.04 0.97±0.01 BDL 2.96 1.18 1.32 JH05 1.31±0.15 1.20±0.15 3.58±0.36 1.74±0.06 7.83 0.36 1.09 SX01 2.14±0.47 2.10±0.61 5.40±0.68 0.73±0.26 10.37 0.40 1.02 SX02 3.61±0.56 3.45±0.75 5.29±7.04 0.17±0.07 12.52 0.68 1.05 SX03 10.25±0.31 6.55±0.09 26.41±1.22 BDL 43.21 0.39 1.56 SX04 BDL BDL BDL BDL BDL - - SX05 1.29±0.03 1.36±0.02 3.80±0.32 2.01±0.03 8.46 0.34 0.95 QZ01 1.19±0.07 1.35±0.03 2.31±0.03 1.27±0.05 6.12 0.52 0.88 QZ02 BDL 0.76±0.044 BDL BDL 0.76 - 0.01
WZ01 1.56±0.19 1.39±0.10 BDL 2.88±0.17 5.83 - 1.12 WZ02 BDL 0.86±0.02 1.09±0.27 BDL 1.96 0 0 WZ03 1.56±0.40 1.46±0.29 1.30±0.39 1.37±0.15 5.69 1.20 1.07 NB01 BDL 6.82±0.66 5.99±0.55 0.88±0.09 13.69 0 0 NB02 BDL 5.77±0.55 BDL BDL 5.78 - 0 NB03 0.62±0.04 0.55±0.06 BDL BDL 1.17 - 1.13 NB04 BDL 0.77±0.01 0.98±0.35 BDL 1.76 0 0 NB05 0.94±0.07 0.89±0.10 6.34±1.49 1.26±0.24 9.43 0.15 1.06 TZ01 BDL BDL BDL BDL BDL - - TZ02 BDL 2.50±0.26 6.21±0.66 BDL 8.71 0 0 TZ03 BDL BDL 1.52±1.30 BDL 1.52 0 - TZ04 1.32±0.15 1.39±0.02 1.44±0.09 1.58±0.13 5.73 0.92 0.95 ZS01 6.22±0.34 6.55±0.38 BDL BDL 12.78 - 0.95 ZS02 1.33±0.20 1.31±0.20 1.69±0.35 1.24±0.17 5.57 0.78 1.02 LS01 2.62±0.45 0.92±0.10 1.28±0.15 BDL 4.82 2.04 2.84 LS02 5.18±0.24 2.86±0.15 27.50±1.34 11.32±0.54 46.86 0.19 1.81
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TABLE SI-3. Concentration of HCHs (ng/g) in soils from different areas of China
Sample location α-HCH γ-HCH β-HCH δ-HCH HCHs
This study 1.86±3.69 1.61±1.93 2.67±5.24 0.67±1.63 6.81±10.17
Vegetable soils of Guangzhou 0.80±0.99 0.76±1.95 2.31±3.72 0.52±1.12 4.39±7.40
Greenhouse soils from Beijing suburbs 1.76±0.85 1.53±1.61 11.92±7.35 0.56±0.42 15.77±6.00
Soils in Haihe plain 0.31±2.01 1.22±18.4 2.25±15.9 0.11±0.53 3.90±26.0
TABLE SI-4. Vertical distribution of HCH isomers (ng/g) in soils at selected sites Sample (depth cm) α-HCH γ-HCH β-HCH δ-HCH HCHs (%)a HZ08 (0-20) 6.01±0.33 4.07±0.18 BDL BDL 10.11 (74.7) HZ08 (20-40) 2.09±0.09 0.55±0.04 0.11±0.01 BDL 2.75 (20.3) HZ08 (40-60) 0.39±0.03 0.23±0.01 BDL BDL 0.62 (4.6) HZ08 (60-100) BDL BDL BDL BDL 0.05 (0.4) HZ08 (total) 8.50 4.86 0.16 0.06 13.53 (100) HZ10 (0-20) 21.43±1.78 7.11±0.52 14.19±0.63 1.36±0.21 44.09 (75.0) HZ10 (20-40) 5.87±0.17 1.80±0.10 3.34±0.09 0.50±0.03 11.51 (19.6) HZ10 (40-60) 1.74±0.06 1.15±0.06 BDL 0.26±0.02 3.16 (5.4) HZ10 (60-100) BDL BDL BDL BDL 0.05 (0) HZ10 (total) 29.05 10.06 17.56 2.14 58.81 (100) HUZ01 (0-20) 1.00±0.10 0.95±0.03 BDL BDL 1.98 (63.9) HUZ01 (20-40) 0.39±0.02 BDL BDL BDL 0.43 (13.9) HUZ01 (40-60) 0.10±0.01 0.03±0.008 BDL BDL 0.16 (5.2) HUZ01 (60-100) 0.34±0.02 0.16±0.01 BDL BDL 0.53 (17.0) HUZ01 (total) 1.83 1.15 0.06 0.06 3.10 (100) HUZ05 (0-20) 0.91±0.04 0.86±0.06 0.77±0.05 BDL 2.56 (79.0) HUZ05 (20-40) 0.13±0.01 0.16±0.01 0.06±0.01 BDL 0.36 (11.1) HUZ05 (40-60) 0.04±0.006 0.09±0.008 0.03±0.005 BDL 0.18 (5.6) HUZ05 (60-100) 0.09±0.007 BDL 0.03±0.004 BDL 0.14 (4.3) HUZ05 (total) 1.17 1.12 0.89 0.06 3.24 (100)
21
HUZ07 (20-40) 0.22±0.02 0.45±0.03 0.40±0.04 0.40±0.03 1.47 (16.5)
HUZ07 (40-60) 0.23±0.02 0.33±0.03 0.44±0.03 0.31±0.02 1.31 (14.7)
HUZ07 (60-100) 0.08±0.01 BDL BDL BDL 0.12 (1.4)
HUZ07 (total) 1.48 2.45 2.96 2.00 8.89 (100)
BDL: Below detection limit, which was statistically analyzed as half of LOQ value. The LOQ values were 0.0200 ng/g for α-HCH and γ-HCH and 0.0300 ng/g for β-HCH and δ-HCH.
a
TABLE SI-5. Enantiomeric fractions (EFs) of αααα-HCH in soils
Sample α-HCH Sample α-HCH Sample α-HCH
HZ 1 0.559±0.013 JX 10 0.481±0.015 WZ 1 0.681±0.026 HZ 2 0.520±0.009 JX 11 0.505±0.010 WZ 2 NA HZ 3 0.542±0.031 HUZ 1 0.771±0.016 WZ 3 0.529±0.026 HZ 4 0.500±0.012 HUZ 2 NA NB 1 NA HZ 5 0.662±0.022 HUZ 3 NA NB 2 NA HZ 6 NA HUZ 4 0.531±0.007 NB 3 0.900±0.010 HZ 7 NA HUZ 5 0.399±0.015 NB 4 NA HZ 8 0.662±0.015 HUZ 6 NA NB 5 0.535±0.023 HZ 9 0.905±0.008 HUZ 7 0.545±0.005 TZ 1 NA HZ 10 0.274±0.020 JH 1 0.500±0.021 TZ 2 NA HZ 11 0.764±0.015 JH 2 0.591±0.014 TZ 3 NA HZ 12 0.685±0.012 JH 3 0.681±0.017 TZ 4 0.642±0.018 JX 1 NA JH 4 0.551±0.008 ZS 1 0.482±0.011 JX 2 NA JH 5 0.728±0.007 ZS 2 0.536±0.020 JX 3 NA SX 1 0.851±0.022 LS 1 0.524±0.012 JX 4 NA SX 2 0.511±0.012 LS 2 0.581±0.009 JX 5 NA SX 3 0.199±0.017 JX 6 0.524±0.017 SX 4 NA JX 7 0.611±0.007 SX 5 0.620±0.028 JX 8 NA QZ 1 0.639±0.012 JX 9 0.803±0.032 QZ 2 NA
23
TABLE SI-6. Correlations among EF of αααα-HCH and concentration, soil properties at all sites, plain, and mountain sites.
All sites(n=38) Equation R P Cbio Y=808.1-779.2x -0.34 0.03 TOC Y=1.16+0.12x 0.03 0.88 pH Y=4.86+0.69x 0.10 0.55 Silt Y=52.87-16.11x -0.12 0.48 Clay Y=28.26-12.46x -0.25 0.13
FIGURE SI-1. Gridded total usage of technical HCH from 1952 to 1984 with 1/6
latitude by 1/4 longitude resolution (around 24 by 24 km). The total usage was approximately 300 kt.
25 FIGURE SI-2. Locations of 58 sampling sites.
27
29 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
HZ08 HZ10 HUZ01 HUZ05 HUZ07
Sampling Sites F ra c ti o n
0-20 cm
20-40 cm
40-60 cm
60-100 cm
FIGURE SI-6. Vertical profiles of total HCHs residues in different layers for the 5 sampling sites.
CD ORD
CD ORD
Literature cited
(1) Champion, Jr. W. L.; Lee J.; Garrison, W. A.; DiMarco, J. C.; Matabea, A.; Prickett, K. B. Liquid chromatographic separation of the enantiomers of trans-chlordane, cis-chlordane, heptachlor, heptachlor epoxide and α-hexachlorocyclohexane with application to small-scale preparative separation.J.
Chromatogr. A 2004, 1024, 55-62.
(2) The China National Environmental Monitoring Center. Modern Analyzing Methods of Soil Quality; China Environmental Science Press: Beijing, 1992.
(3) NYT 1121.3-2006, Soil testing part 3: Method for determination of soil mechanical composition; Ministry of Agriculture of the People’s Republic of China: Beijing, 2006.
(4) Witt, C.; Gaunt, J. L.; Galicia, C. C.; Ottow, J. C. C.; Neue, H-U. A rapid chloroform-fumigation extraction method for measuring soil microbial biomass carbon and nitrogen in flooded rice soils. Biol.
Fertil. Soils 2000, 30, 510-519.
(5) Wu, J. S.; Lin, Q. M.; Huang, Q. Y.; Xiao, H. A. In soil microbial biomass — Methods and application; China Meteorological Press: Beijing, 2006.
