<p> 1 The occurrence and fate of tetracyclines in two pharmaceutical 2 wastewater treatment plants of northern China</p><p>3 4 This supporting information contains the following sections:</p><p>5 6 Text S1 Pretreatment and solid phase extraction for sludge samples</p><p>7 Table S1 Target compounds and their information</p><p>8 Table S2 Analytical method validation </p><p>9 Table S3 Data for Fig.2</p><p>10 Table S4 Data for Fig.3 11 Text S1. Pretreatment and solid phase extraction for sludge samples</p><p>12 A mass of 0.5 g lyophilized and sieved sludge sample was spiked with a mixture of</p><p>13 four surrogates (25 ng SD-13C6 for SAs, 25 ng LOM for FQs, 25 ng MECL for TCs, and</p><p>14 25 ng CAF-13C3 for other compounds). The mixture was extracted by 10 mL methanol-</p><p>15 EDTA-citrate buffer (V/V/V=3:1:2), vortexed for 1 min at 2500 rpm, ultrasonicated for</p><p>16 15 min (50 kHz, 300 W), and then centrifuged at 6140 g for 10 min. In additions, The</p><p>17 concentration of the EDTA is 0.1 mol/L. And the citrate buffer solution is</p><p>18 made by mixing the citric acid (0.1 mol/L) and sodium citrate (0.1 mol/L) with</p><p>19 the volume proportion of 41:59. The resulting supernatant was collected into brown glass</p><p>20 bottle and stored at 4ºC. The procedure was repeated three times and then the resulting</p><p>21 supernatant was combined together diluted with Milli-Q water to 500 mL, filtered</p><p>22 through 0.45 μm glass fiber filters, and adjusted to pH 4. Subsequently, the resulting</p><p>23 solution was purified and enriched by SPE using Oasis HLB cartridges (6 mL, 500 mg,</p><p>24 Waters, Watford, UK) and Strata strong anion exchanger (SAX) (3 mL/200 mg,</p><p>25 Thermo ， USA) cartridge connected in tandem (HLB was placed before SAX). The</p><p>26 cartridges were preconditioned sequentially with 5.0 mL of methanol and 5.0 mL of</p><p>27 Milli-Q water. Each sample passed through the cartridge at a flow rate of approximately</p><p>28 3-5 mL min-1. Afterwards, the SAX cartridges were removed and HLB cartridges were</p><p>29 rinsed with 5ml deionized sterile water, air dried for 10 minutes, and eluted with 1.5 ml</p><p>30 acetone and 3.5 ml of methanol. The eluate was collected and dried under a gentle stream</p><p>-1 31 of N2, resulting in approximately 100 μL sample, then spiked with 10 μL of 10 mg L</p><p>32 simatone as an internal standard, and reconstituted to approximately 1 mL with the initial</p><p>33 mobile phase and the supernatant was filtered through 0.22 μm PES filters (PALL, USA),</p><p>2 34 which was stored at -18 ºC until UPLC–MS/MS analysis.</p><p>S3 35 Table S1. Target compounds and their information</p><p>Log MWb Antibiotic Group Compound Molecular formula pK a a Kow (g mol-1) Sulfonamides Sulfamethoxazole C H N O S 1.74/5.7 NA 253.28 (SMX) 10 11 3 3 Sulfadiazine C H N O S 2.49/6.4 -0.09 250.28 (SD) 10 10 4 2 Sulfamethazin e C12H14N4O2S 2.07/7.5 0.89 278.33 (SM2) Sulfadimethox ine C12H14N4O4S NA NA 310.3 (SDM) Sulfachlorpyri dazine C10H9ClN4O2S 5.1/7.4 0.28 284.72 (SCP) Trimethoprim C H N O 7.12 0.91 290.32 (TMP) 14 18 4 3 Tetracyclines Tetracycline 3.7/7.8/9. C H N O 0.09 444.43 (TC) 22 24 2 8 6 Oxytetracycli ne C22H24N2O9 3.2/7.8/9.6 0.08 460.43 (OTC) Chlortetracycl ine C22H28ClN2O8 3.3/7.5/8.9 NA 483.91 (CTC) Doxycycline C H N O 3.5/7.7/9.5 NA 444.45 (DOXY) 22 24 2 8 Fluoroquinolone Enrofloxacin s (ENR) C19H22FN3O3 6.27/8.3 2.53 359.39 Ciprofloxacin C H FN O 6.09/8.62 0.25 331.34 (CIP) 17 18 3 3 Ofloxacin C H FN O 5.97/7.65 NA 361.38 (OFL) 18 20 3 4 Macrolides Roxithromycin (ROX) C41H76N2O15 9.2 2.75 837.05 Erythromycin C H NO 8.8 3.06 733.93 (ERY) 37 67 13 Tylosin C H NO 7.37/13 NA 916.11 (TYL) 46 77 17 β-lactams Ampicillin (AMP) C16H19N3O4S 2.7/7.3 NA 349.4 Cefalexin C H N O S 2.56/6.88 NA 347.39 (CLX) 16 17 3 4</p><p>4 Surrogates Meclocycline C H C N O S NA NA 695.05 (MECL) 29 27 l 2 14 Lomefloxacin C H F N O NA NA 351.35 (LOME) 17 19 2 3 3 13 13 caffeine-trimethyl- C3  C3C5H10  1 13 (CAF- C3) N4O2 NA NA 97.17</p><p> sulfadiazine-phenyl- 13 13  C4 C6H10  2 C6 NA NA 13 N4O2S 56.23 (SD- C6) Internal Standard Simetone  C H N  1 8 15 5 NA NA O 97.28 36</p><p>37 pKa = acidity constant; Log Kow = octanol–water partition coefficient; MW = molecular weight. 38 NA : data is unavailable 39</p><p>S5 40 Table S2-1Analytical method validation</p><p>Spiked/ Recovery/% RSDa % (μg/kg) LODb LOQc sludge sludge sludge Sludge Sludge Compounds (μg/kg) (μg/kg) SD 50.0 74.3 4.5 0.6 2.6 100.0 82.1 3.4 500.0 83.6 3.7 SMX 50.0 69.5 4.6 0.3 1.0 100.0 62.7 1.3 500.0 75.4 2.5 SM2 50.0 87.1 3.2 0.5 2.6 100.0 90.6 2.4 500.0 92.7 1.3 SDM 50.0 75.3 3.9 0.5 1.7 100.0 85.2 4.7 500.0 79.4 2.4 SCP 50.0 75.0 2.6 0.1 0.3 100.0 73.4 4.0 500.0 78.1 2.4 TMP 50.0 81.5 3.1 0.5 1.7 100.0 76.2 2.5 500.0 83.7 3.2 TC 50.0 70.3 1.3 1.0 2.6 100.0 73.4 4.1 500.0 67.2 3.2 OTC 50.0 69.1 4.4 0.5 2.6 100.0 83.7 2.8 500.0 72.3 4.2 CTC 50.0 67.9 3.8 0.8 1.7 100.0 68.6 2.3 500.0 73.2 2.6 DOXY 50.0 60.1 3.0 0.8 3.3 100.0 67.9 1.4 500.0 69.2 2.6 CIP 50.0 65.3 4.1 1.2 3.3 100.0 74.6 2.3 500.0 75.3 1.4 ENR 50.0 72.6 3.3 0.8 1.7 100.0 79.8 2.0 500.0 70.4 3.4 </p><p>6 OFL 50.0 73.6 2.7 1.0 2.4 100.0 75.9 3.1 500.0 78.3 2.5 ERY 50.0 67.1 3.5 0.5 2.0 100.0 71.3 2.6 500.0 73.9 0.8 ROX 50.0 77.2 3.1 0.8 2.6 100.0 83.3 2.7 500.0 71.5 4.6 TYL 50.0 62.5 2.2 0.5 1.7 100.0 64.8 3.4 500.0 68.3 2.6 AMP 50.0 72.3 0.5 1.0 2.6 100.0 76.9 2.7 500.0 71.0 2.1 CLX 50.0 86.3 3.4 1.2 2.3 100.0 88.9 2.6 500.0 83.7 4.2 sulfadiazin 50.0 65.4 3.2 1.9 2.7 13 e- C6 100.0 69.5 2.9 500.0 72.3 2.1 meclocycli 50.0 69.2 3.2 2.1 2.5 ne 100.0 68.3 2.1 500.0 69.5 1.9 50.0 70.1 2.5 1.8 3.1 lomefloxac 100.0 72.3 2.8 in 500.0 73.5 2.9 50.0 64.7 3.1 2.5 3.2 100.0 70.2 2.8 caffeine- 500.0 75.2 2.6 13 C3 41 42</p><p>43 Table S2-2Analytical method validation </p><p>LODb LOQc Spiked/( ng/L) Recovery/% RSDa % Water Water Compounds water water water (ng/L) (ng/L) SD 50.0 82.1 4.3 1.8 3.8 100.0 81.1 3.2 500.0 79.8 4.1 SMX 50.0 77.6 4.0 1.0 1.6 100.0 84.3 1.7 500.0 76.4 2.8 </p><p>S7 SM2 50.0 83.2 3.5 1.2 3.0 100.0 91.2 3.4 500.0 89.3 3.3 SDM 50.0 78.4 1.9 1.3 2.0 100.0 87.6 3.7 500.0 73.7 2.1 SCP 50.0 78.0 2.2 0.3 1.2 100.0 76.5 3.0 500.0 78.4 3.4 TMP 50.0 80.0 3.5 1.5 2.0 100.0 77.3 1.5 500.0 81.2 3.2 TC 50.0 72.1 1.6 3.0 4.2 100.0 75.6 4.3 500.0 69.8 2.2 OTC 50.0 70.3 4.3 1.5 2.0 100.0 84.3 1.8 500.0 77.2 2.2 CTC 50.0 72.5 3.3 2.8 3.2 100.0 69.8 2.4 500.0 73.2 2.5 DOXY 50.0 62.3 2.0 2.0 2.6 100.0 69.3 1.5 500.0 68.5 1.6 CIP 50.0 70.2 2.5 3.2 4.8 100.0 72.4 1.3 500.0 79.7 2.4 ENR 50.0 76.4 2.3 2.5 4.0 100.0 81.2 2.4 500.0 82.1 2.7 OFL 50.0 72.1 1.7 3.0 4.2 100.0 78.4 2.1 500.0 80.2 3.5 ERY 50.0 77.1 3.6 1.5 2.6 100.0 67.4 2.7 500.0 72.5 1.3 ROX 50.0 78.3 2.1 2.4 3.0 100.0 80.2 2.8 500.0 77.5 3.6 TYL 50.0 67.5 2.5 1.5 2.0 100.0 68.9 3.2 500.0 66.4 1.6 AMP 50.0 78.4 0.9 2.0 3.2 </p><p>8 100.0 73.2 2.3 500.0 75.6 2.5 CLX 50.0 86.4 2.4 3.6 4.2 100.0 85.3 2.6 500.0 82.5 3.2 sulfadiazine- 50.0 65.7 3.0 3.2 3.6 13 C6 100.0 68.5 2.8 500.0 70.1 2.7 meclocycline 50.0 75.4 3.4 2.6 3.1 100.0 71.8 2.3 500.0 69.8 2.1 lomefloxacin 50.0 72.1 3.2 2.8 3.0 100.0 73.4 3.1 500.0 69.8 2.9 13 caffeine- C3 50.0 75.3 3.4 2.5 3.3 100.0 70.2 3.2 500.0 69.8 2.7 44 45 a Relative standard deviations (RSD) were calculated from triplicate samples spiked at the same concentration. 46 b Limit of detection (LOD) was calculated from the concentration that yielded a signal-to-noise (S/N) ratio of higher 47 than or equal to 3. 48 c Limit of quantification (LOQ) was defined as the lowest concentration level corresponding to a signal-to-noise (S/N) 49 ratio of 10. 50 51 Table S3 Data for Fig.2 PWWTP1 OTC TC CTC W1(mg/L) 334.31±43 11.92±2 1.78±0.4 W2(mg/L) 65.67±12 2.27±0.3 0.38±0.09 W3(mg/L) 63.69±11 2.25±0.4 0.35±0.08 W4(mg/L) 50.88±8 1.31±0.2 0.39±0.12 W5(mg/L) 31.95±6 0.44±0.1 0.31±0.1 S1(mg/kg) 5481.15±123 299.26±34 25.42±3 PWWTP2 OTC TC CTC W1'(mg/L) 2.36±0.6 60.97±12 0.75±0.12 W2'(mg/L) 0.44±0.1 11.45±3.3 0.14±0.04 W3'(mg/L) 0.43±0.09 10.85±3 0.138±0.05 W4'(mg/L) 0.28±0.11 6.62±1.7 0.086±0.01 W5'(mg/L) 0.13±0.07 2.6±0.8 0.031±0.006 S1'(mg/kg) 48.41±9.5 1950.12±74 22.08±3.9 52 53 PWWTP1: W1: Influent; W2: Dilution wastewater from the influent; W3: Effluent of regulating tank; W4: Effluent of 54 EGSB; W5: Effluent of MBR. 55 PWWTP2: W1’: Influent; W2’: Dilution wastewater from the influent; W3’:Effluent of regulating tank; W4’: Effluent 56 of SBR; W5’: Effluent of B-COT. 57 58 59 60</p><p>S9 61 62 63 Table S4 Data for Fig.3 PWWTP1 Effluent Sludge adsorption Degradation OTC（%） 37.6±3.2 12.6±2.2 49.8±4.2 TC（%） 26.3±4.1 20±3.1 53.7±6.1 CTC（%） 38.0±5.4 17.2±2.9 44.8±1.3 PWWTP2 Effluent Sludge adsorption Degradation OTC（%） 32.2±2.5 21.9±5.2 45.9±6.3 TC（%） 26.4±6.1 33.5±2.9 40.1±3.8 CTC（%） 21.7±4.3 18.7±1.4 59.6±2.2 64</p><p>10</p>