Supplementary Material

Occurrence and Distribution of Pesticides in Precipitation as Revealed by Targeted

Screening through GC-MS/MS

Hui Zhang a, Simon Watts a, b, Martin C. Philix a, Shane A. Snyder a, c, Choon Nam Ong a, d *

a NUS Environmental Research Institute, National University of Singapore, Singapore, 117411, Singapore

b Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore

c Department of Chemical and Environmental Engineering, University of Arizona, Tucson 85721, AZ, USA

d Saw Swee Hock School of Public Health, National University of Singapore, Singapore, 117549, Singapore

Correspondence: Choon Nam Ong, PhD, NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, T-Lab Building #02-01, Singapore, 117411. Tel. 65-6516 4982. Email: eridir@nus.edu.sg.

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Table Captions:

Table S1. List of OCPs, n-alkanes and internal standard.

Table S2. Pesticides in Shimadzu Smart Pesticides Database.

Table S3. Retention indies and MRM transitions of pesticides and internal standards added into Smart Pesticides Database.

Table S4. Detection frequencies (DFs) of pesticides in 101 precipitation samples.

Table S5. Spearman correlation of detected pesticides in precipitation.

Figure Caption:

Figure S1. Occurrence of pesticides in precipitation collected between October 2015 and March 2017.

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Table S1. List of OCPs, n-alkanes and internal standard.

Compound CAS Compound CAS

OCPs n-alkanesα-HCH 319-84-6 n-Pentadecane (C15) 629-62-9β-HCH 319-85-7 n-Hexadecane (C16) 544-76-3γ-HCH 58-89-9 n-Heptadecane (C17) 629-78-7δ-HCH 319-86-8 n-Octadecane (C18) 593-45-3Heptachlor 76-44-8 n-Nonadecane (C19) 629-92-5Heptachlor epoxide 1024-57-3 n-Eicosane (C20) 112-95-8trans-Chlordane 5103-74-2 n-Heneicosane (C21) 629-94-7cis-Chlordane 5103-71-9 n-Docosane (C22) 629-97-0α-Endosulfan 959-98-8 n-Tricosane (C23) 638-67-5β-Endosulfan 33213-65-9 n-Tetracosane (C24) 646-31-1Endosulfan sulfate 1031-07-8 n-Pentacosane (C25) 629-99-2trans-Nonachlor 39765-80-5 n-Hexacosane (C26) 630-01-3cis-Nonachlor 5103-73-1 n-Heptacosane (C27) 593-49-7Aldrin 309-00-2 n-Octacosane (C28) 630-02-4Dieldrin 60-57-1 n-Nonacosane (C29) 630-03-5Endrin 72-20-8 n-Triacontane (C30) 638-68-6p,p'-DDE 72-55-9 n-Hentriacontane (C31) 630-04-6p,p'-DDD 72-54-8 n-Dotriacontane (C32) 544-85-4p,p'-DDT 50-29-3 n-Tritriacontane (C33) 630-05-7Endrin aldehyde 7421-93-4 n-Tetratriacontane (C34) 14167-59-0Endrin ketone 53494-70-5 n-Pentatriacontane (C35) 630-07-9Methoxychlor 72-43-5 n-Hexatriacontane (C36) 630-06-8

n-Heptatriacontane (C37) 7194-84-5n-alkanes n-Octatriacontane (C38) 7194-85-6n-Octane (C8) 111-65-9 n-Nonatriacontane (C39) 7194-86-7n-Nonane (C9) 111-84-2 n-Tetracontane (C40) 4181-95-7n-Decane (C10) 124-18-5 Pristane (C19)* 1921-70-6n-Undecane (C11) 1120-21-4 Phytane (C20)* 638-36-8n-Dodecane (C12) 112-40-3n-Tridecane (C13) 629-50-5 Internal Standardn-Tetradecane (C14) 629-59-4 Phenanthrene-d10

Note: * Pristane and phytane were not used for estimation of retention time.

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Table S2. Pesticides in Shimadzu Smart Pesticides Database.

Compound CAS Compound CAS

Aldicarb deg. 0 - 00 - 0 Ethoprophos 13194 - 48 - 4DCIP 108 - 60 - 1 Ethalfluralin 55283 - 68 - 6Aldoxycarb deg. 0 - 00 - 0 Phenmedipham deg. 0 - 00 - 0Chlofentezine deg. 0 - 00 - 0 Naled 300 - 76 - 5Hymexazol 10004 - 44 - 1 Chlorpropham 101 - 21 - 3Methamidophos 10265 - 92 - 6 Dichlofluanid metabolite 0 - 00 - 0Dichlorvos 62 - 73 - 7 Trifluralin 1582 - 09 - 8Nereistoxin 1631 - 58 - 9 Dicrotophos 141 - 66 - 2Allidochlor 93 - 71 - 0 Flusilazole metabolite 0 - 00 - 0Dichlobenil 1194 - 65 - 6 2,6-Dichlorobenzamide 2008 - 58 - 4EPTC 759 - 94 - 4 Benfluralin 1861 - 40 - 1Biphenyl 92 - 52 - 4 Dioxabenzofos (Salithion) 3811 - 49 - 2Propamocarb 24579 - 73 - 5 Bendiocarb 22781 - 23 - 3Mevinphos-1 7786 - 34 - 7 Sulfotep 3689 - 24 - 5Mevinphos-2 7786 - 34 - 7 Monocrotophos 6923 - 22 - 4Butylate 2008 - 41 - 5 Cadusafos 95465 - 99 - 9Chlormephos 24934 - 91 - 6 Di-allate-1 2303 - 16 - 4Acephate 30560 - 19 - 1 Phorate 298 - 02 - 2Nitrapyrin 1929 - 82 - 4 α-HCH 319 - 84 - 6Etridiazole 2593 - 15 - 9 Hexachlorobenzene 118 - 74 - 1Metolcarb 1129 - 41 - 5 Di-allate-2 2303 - 16 - 43-Hydroxycarbofuran 16655 - 82 - 6 Thiometon 640 - 15 - 3Methacrifos 62610 - 77 - 9 Dicloran 99 - 30 - 9Clothianidin 210880 - 92 - 5 Dimethoate 60 - 51 - 5Thiocyclam 31895 - 21 - 3 Desmedipham deg. 0 - 00 - 0Chloroneb 2675 - 77 - 6 Furilazole 121776 - 33 - 8Crimidine 535 - 89 - 7 Carbofuran 1563 - 66 - 22-Phenylphenol 90 - 43 - 7 Simazine 122 - 34 - 9Tebuthiuron 34014 - 18 - 1 Atrazine 1912 - 24 - 9Isoprocarb 2631 - 40 - 5 Dimethipin 55290 - 64 - 7Molinate 2212 - 67 - 1 Swep 1918 - 18 - 9XMC 2655 - 14 - 3 β-HCH 319 - 85 - 7Tecnazene 117 - 18 - 0 Chlorbufam 1967 - 16 - 4Omethoate 1113 - 02 - 6 Clomazone 81777 - 89 - 1Xylylcarb 2425 - 10 - 7 Quintozene 82 - 68 - 8Fenobucarb 3766 - 81 - 2 Propazine 139 - 40 - 2Propoxur 114 - 26 - 1 Dioxathion deg. 0 - 00 - 0Propachlor 1918 - 16 - 7 Tolylfluanid metabolite 0 - 00 - 0Chlorethoxyfos 54593 - 83 - 8 γ-HCH (Lindane) 58 - 89 - 9Demeton-S-methyl (Methyl demeton) 919 - 86 - 8 Propentamphos 31218 - 83 - 4

Diphenylamine 122 - 39 - 4 Terbufos 13071 - 79 - 9

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Table S2. Continued.

Compound CAS Compound CAS

Cyanophos 2636 - 26 - 2 Parathion-methyl 298 - 00 - 0Fonofos 944 - 22 - 9 Tolclofos-methyl 57018 - 04 - 9Propyzamide 23950 - 58 - 5 Simeconazole 149508 - 90 - 7Pyroquilon 57369 - 32 - 1 Alachlor 15972 - 60 - 8Diazinon 333 - 41 - 5 Tridemorph 81412 - 43 - 3Phosphamidon-1 13171 - 21 - 6 Simetryn 1014 - 70 - 6Pyrimethanil 53112 - 28 - 0 Heptachlor 76 - 44 - 8Chlorothalonil 1897 - 45 - 6 Carbaryl 63 - 25 - 2Disulfoton 298 - 04 - 4 Ametryn 834 - 12 - 8Prohydrojasmon-1 158474 - 72 - 7 Metalaxyl (Mefenoxam) 57837 - 19 - 1Isazofos 42509 - 80 - 8 Fenchlorphos 299 - 84 - 3Tefluthrin 79538 - 32 - 2 Cinmethylin 87818 - 31 - 3Terbacil 5902 - 51 - 2 Prometryn 7287 - 19 - 6Etrimfos 38260 - 54 - 7 Dithiopyr 97886 - 45 - 8δ-HCH 319 - 86 - 8 Pirimiphos-methyl 29232 - 93 - 7Tri-allate 2303 - 17 - 5 2-(1-Naphthyl)acetamide 86 - 86 - 2MCPA-thioethyl 25319 - 90 - 8 Terbutryn 886 - 50 - 0Tebupirimfos 96182 - 53 - 5 Spiroxamine-2 118134 - 30 - 8Pirimicarb 23103 - 98 - 2 Fenitrothion 122 - 14 - 5Iprobenfos 26087 - 47 - 8 Methiocarb 2032 - 65 - 7Prohydrojasmon-2 158474 - 72 - 7 Ethofumesate 26225 - 79 - 6Oxabetrinil 74782 - 23 - 3 Probenazole 27605 - 76 - 1Benoxacor 98730 - 04 - 2 (E)-Dimethylvinphos 2274 - 67 - 1Formothion 2540 - 82 - 1 Linuron 330 - 55 - 2MCPB-ethyl 10443 - 70 - 6 Bromacil 314 - 40 - 9Ethiofencarb 29973 - 13 - 5 Dichlofluanid 1085 - 98 - 9Phosphamidon-2 13171 - 21 - 6 Esprocarb 85785 - 20 - 2Benfuresate 68505 - 69 - 1 Malathion 121 - 75 - 5Dichlofenthion 97 - 17 - 6 Quinoclamine 2797 - 51 - 5Dimethenamid (Dimethenamid-P) 87674 - 68 - 8 Metolachlor (S-

Metolachlor) 51218 - 45 - 2

Terbucarb 1918 - 11 - 2 Chlorpyrifos 2921 - 88 - 2Propanil 709 - 98 - 8 Thiobencarb 28249 - 77 - 6Acetochlor 34256 - 82 - 1 Aldrin 309 - 00 - 2Bromobutide 74712 - 19 - 9 (Z)-Dimethylvinphos 2274 - 67 - 1Chlorpyrifos-methyl 5598 - 13 - 0 Diethofencarb 87130 - 20 - 9Metribuzin 21087 - 64 - 9 Fenthion 55 - 38 - 9Oxpoconazole-formyl deg. 0 - 00 - 0 Chlorthal-dimethyl 1861 - 32 - 1

Vinclozolin 50471 - 44 - 8 Cyanazine 21725 - 46 - 2Spiroxamine-1 118134 - 30 - 8 Fenpropimorph 67564 - 91 - 4

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Table S2. Continued.

Compound CAS Compound CAS

Parathion 56 - 38 - 2 Diclocymet-1 139920 - 32 - 4Flufenacet 142459 - 58 - 3 Quinalphos 13593 - 03 - 8Isofenphos oxon 31120 - 85 - 1 Thiabendazole 148 - 79 - 8Triadimefon 43121 - 43 - 3 Captan 133 - 06 - 2Tetraconazole 112281 - 77 - 3 Dimepiperate 61432 - 55 - 1Isocarbophos 24353 - 61 - 5 Procymidone 32809 - 16 - 8Dimethachlon 24096 - 53 - 5 Triadimenol-1 55219 - 65 - 3Carbetamide 16118 - 49 - 3 Zoxamide deg. 0 - 00 - 0Dicofol deg. (DCBP) 0 - 00 - 0 Triflumizole 99387 - 89 - 0Nitrothal-isopropyl 10552 - 74 - 6 Folpet 133 - 07 - 3Butralin 33629 - 47 - 9 Methoprene 40596 - 69 - 8Phthalide 27355 - 22 - 2 Ferimzone 89269 - 64 - 7Bromophos 2104 - 96 - 3 Triadimenol-2 55219 - 65 - 3Diphenamid 957 - 51 - 7 Bromophos-ethyl 4824 - 78 - 6Fosthiazate-1 98886 - 44 - 3 Methidathion 950 - 37 - 8Fosthiazate-2 98886 - 44 - 3 trans-Chlordane 5103 - 74 - 2Isofenphos-methyl 99675 - 03 - 3 Chlorbenside 103 - 17 - 3Thiamethoxam deg. 0 - 00 - 0 Diclocymet-2 139920 - 32 - 4Pendimethalin 40487 - 42 - 1 Propaphos 7292 - 16 - 2(E)-Chlorfenvinphos 470 - 90 - 6 Chinomethionat 2439 - 01 - 2Cyprodinil 121552 - 61 - 2 o,p'-DDE 3424 - 82 - 6Fipronil 120068 - 37 - 3 (E)-Pyrifenox 88283 - 41 - 4Anirazine 101 - 05 - 3 Tetrachlorvinphos 22248 - 79 - 9Dimethametryn 22936 - 75 - 0 Trichlamide 70193 - 21 - 4Penconazole 66246 - 88 - 6 Paclobutrazol 76738 - 62 - 0Heptachlor-exo-epoxide 1024 - 57 - 3 Butachlor 23184 - 66 - 9oxy-Chlordane 27304 - 13 - 8 Disulfoton sulfone 2497 - 06 - 5Chlozolinate 84332 - 86 - 5 Fenothiocarb 62850 - 32 - 2Phosfolan 947 - 02 - 4 cis-Chlordane 5103 - 71 - 9Tolylfluanid 731 - 27 - 1 alpha-Endosulfan 959 - 98 - 8Isofenphos 25311 - 71 - 1 Mepanipyrim 110235 - 47 - 7(Z)-Pyrifenox 88283 - 41 - 4 Ditalimfos 5131 - 24 - 8Allethrin-1,2 584 - 79 - 2 trans-Nonachlor 39765 - 80 - 5(Z)-Chlorfenvinphos 470 - 90 - 6 Butamifos 36335 - 67 - 8

Ethychlozate 27512 - 72 - 7 Imazamethabenz-methyl-1 81405 - 85 - 8

Heptachlor-endo-epoxide 28044 - 83 - 9 Imazamethabenz-methyl-2 81405 - 85 - 8

Mecarbam 2595 - 54 - 2 Flutriafol 76674 - 21 - 0Allethrin-3,4 (Bioallethrin) 584 - 79 - 2 Fenamiphos 22224 - 92 - 6

Phenthoate 2597 - 03 - 7 Napropamide 15299 - 99 - 7

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Table S2. Continued.

Compound CAS Compound CAS

TCMTB 21564 - 17 - 0 Aramite-4 143 - 57 - 8Flutolanil 66332 - 96 - 5 Cyproconazole-2 94361 - 06 - 5Chlorfenson 80 - 33 - 1 Chlorthiophos-1 60238 - 56 - 4Hexaconazole 79983 - 71 - 4 Fenoxanil 115852 - 48 - 7Imazalil 35554 - 44 - 0 Nitrofen 1836 - 75 - 5(E)-Metominostrobin 133408 - 50 - 1 Endrin 72 - 20 - 8

Prothiofos 34643 - 46 - 4 1,1-Dichloro-2,2-bis(4-ethylphenyl)ethane 72 - 56 - 0

Fludioxonil 131341 - 86 - 1 Flufenpyr-ethyl 188489 - 07 - 8Isoprothiolane 50512 - 35 - 1 Chlorthiophos-2 60238 - 56 - 4Pretilachlor 51218 - 49 - 6 (Z)-Pyriminobac-methyl 136191 - 64 - 5Isoxathion oxon 32306 - 29 - 9 Chlorobenzilate 510 - 15 - 6Profenofos 41198 - 08 - 7 Chloropropylate 5836 - 10 - 2Tricyclazole 41814 - 78 - 2 Fensulfothion 115 - 90 - 2p,p'-DDE 72 - 55 - 9 beta-Endosulfan 33213 - 65 - 9Uniconazole (Uniconazole-P) 83657 - 17 - 4 Diniconazole 83657 - 24 - 3

Oxadiazon 19666 - 30 - 9 Oxadixyl 77732 - 09 - 3Thifluzamide 130000 - 40 - 7 cis-Nonachlor 5103 - 73 - 1Tribufos 78 - 48 - 8 p,p'-DDD 72 - 54 - 8Aramite-1 140 - 57 - 8 Ethion 563 - 12 - 2Flamprop-methyl 52756 - 25 - 9 o,p'-DDT 789 - 02 - 6Barban 101 - 27 - 9 Chlorthiophos-3 60238 - 56 - 4Dieldrin 60 - 57 - 1 Fluacrypyrim 229977 - 93 - 9Aramite-2 141 - 57 - 8 Mepronil 55814 - 41 - 0Myclobutanil 88671 - 89 - 0 Triazophos 24017 - 47 - 8o,p'-DDD 53 - 19 - 0 Sulprofos 35400 - 43 - 2Flusilazole 85509 - 19 - 9 Pyrethrin I 121 - 21 - 1Oxyfluorfen 42874 - 03 - 3 Famphur 52 - 85 - 7Bupirimate 41483 - 43 - 6 Isoxadifen-ethyl 163520 - 33 - 0Buprofezin 69327 - 76 - 0 Azamethiphos 35575 - 96 - 3Kresoxim-methyl 143390 - 89 - 0 Carfentrazone-ethyl 128639 - 02 - 1Carboxin 5234 - 68 - 4 Benalaxyl 71626 - 11 - 4Imibenconazole-debenzyl 154221 - 27 - 9 Chlornitrofen 1836 - 77 - 7Diclobutrazol 75736 - 33 - 3 Carbophenothion 786 - 19 - 6Aramite-3 142 - 57 - 8 Cyanofenphos 13067 - 93 - 1(Z)-Metominostrobin 133408 - 51 -2 Trifloxystrobin 141517 - 21 - 7Azaconazole 60207 - 31 - 0 Edifenphos 17109 - 49 - 8Cyflufenamid 180409 - 60 - 3 Norflurazon 27314 - 13 - 2Chlorfenapyr 122453 - 73 - 0 Propiconazole-1 60207 - 90 - 1Isoxathion 18854 - 01 - 8 Quinoxyfen 124495 - 18 - 7Cyproconazole-1 94361 - 06 - 5 (E)-Pyriminobac-methyl 136191 - 64 - 5

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Table S2. Continued.

Compound CAS Compound CAS

Endosulfan sulfate 1031 - 07 - 8 Chlorantraniliprole 500008 - 45 - 7Lenacil 2164 - 08 - 1 Etoxazole 153233 - 91 - 1Propiconazole-2 60207 - 90 - 1 Fenpropathrin 39515 - 41 - 8Pyraflufen-ethyl 129630 - 17 - 7 Fenamidone 161326 - 34 - 7p,p'-DDT 50 - 29 - 3 Tebufenpyrad 119168 - 77 - 3Chloridazon 1698 - 60 - 8 Indanofan 133220 - 30 - 1Hexazinone 51235 - 04 - 2 Anilofos 64249 - 01 - 0Thenylchlor 96491 - 05 - 3 Bifenox 42576 - 02 - 3Tebuconazole 107534 - 96 - 3 Etoxazole metabolite 0 - 00 - 0Diclofop-methyl 51338 - 27 - 3 Bromuconazole-2 116255 - 48 - 2Propargite-1 2312 - 35 - 8 Fenazaquin 120928 - 09 - 8Propargite-2 2312 - 35 - 8 Clomeprop 84496 - 56 - 0Diflufenican 83164 - 33 - 4 Furametpyr 123572 - 88 - 3Resmethrin-1 10453 - 86 - 8 Phenothrin-1 26002 - 80 - 2Piperonyl butoxide 51 - 03 - 6 Furathiocarb 56907 - 30 - 4Captafol 2425 - 06 - 1 Iprodione metabolite 63637 - 89 - 8Nitralin 4726 - 14 - 1 Tetradifon 116 - 29 - 0Resmethrin-2 (Bioresmethrin) 10453 - 86 - 8 Phenothrin-2 26002 - 80 - 2

Epoxiconazole 106325 - 08 - 0 Pentoxazone 110956 - 75 - 7Zoxamide 156052 - 68 - 5 Triticonazole 131983 - 72 - 7Mefenpyr-diethyl 135590 - 91 - 9 Phosalone 2310 - 17 - 0Pyributicarb 88678 - 67 - 5 Leptophos 21609 - 90 - 5Chlomethoxyfen (Chlormethoxynil) 32861 - 85 - 1 Azinphos-methyl 86 - 50 - 0

Pyridaphenthion 119 - 12 - 0 Pyriproxyfen 95737 - 68 - 1Carbosulfan 55285 - 14 - 8 Cyhalothrin-1 68085 - 85 - 8Iprodione 36734 - 19 - 7 Cyhalofop-butyl 122008 - 85 - 9Acetamiprid 135410 - 20 - 7 Mefenacet 73250 - 68 - 7Tetramethrin-1 7696 - 12 - 0 Furametpyr metabolite 0 - 00 - 0Bromuconazole-1 116255 - 48 - 2 Acrinathrin-1 101007 - 06 - 1Phosmet 732 - 11 - 6 Amitraz 33089 - 61 - 1Bifenthrin 82657 - 04 - 3 lambda-Cyhalothrin 91465 - 08 - 6EPN 2104 - 64 - 5 Cyhalothrin-2 68085 - 85 - 8Bromopropylate 18181 - 80 - 1 Mirex 2385 - 85 - 5Piperophos 24151 - 93 - 7 Acrinathrin-2 101007 - 06 - 1Picolinafen 137641 - 05 - 5 Pyrazophos 13457 - 18 - 6Tetramethrin-2 7696 - 12 - 0 Fenarimol 60168 - 88 - 9Fenoxycarb 79127 - 80 - 3 Benfuracarb 82560 - 54 - 1Bifenazate 149877 - 41 - 8 Azinphos-ethyl 2642 - 71 - 9Methoxychlor 72 - 43 - 5 Dialifos 10311 - 84 - 9

8

Table S2. Continued.

Compound CAS Compound CAS

Pyraclofos 77458 - 01 - 6 Pyrimidifen 105779 - 78 - 0Fenoxaprop-ethyl (Fenoxaprop-P-ethyl) 66441 - 23 - 4 Flumioxazin 103361 - 09 - 7

Oryzalin 19044 - 88 - 3 Fenvalerate-1 51630 - 58 - 1Spirodiclofen 148477 - 71 - 8 Pyraclostrobin 175013 - 18 - 0Bitertanol-1 55179 - 31 - 2 tau-Fluvalinate-1 102851 - 06 - 9Permethrin-1 52645 - 53 - 1 Fluvalinate-1 69409 - 94 - 5Bitertanol-2 55179 - 31 - 2 tau-Fluvalinate-2 102851 - 06 - 9Coumaphos 56 - 72 - 4 Fluvalinate-2 69409 - 94 - 5

Permethrin-2 52645 - 53 - 1 Fenvalerate-2 (Esfenvalerate) 51630 - 58 - 1

Fluquinconazole 136426 - 54 - 5 Difenoconazole-1 119446 - 68 - 3Pyridaben 96489 - 71 - 3 Difenoconazole-2 119446 - 68 - 3Dioxathion 78 - 34 - 2 Pyrazoxyfen 71561 - 11 - 0

Prochloraz 67747 - 09 - 5 Deltamethrin-1 (Tralomethrin deg.-1) 52918 - 63 - 5

Oxpoconazole 134074 - 64 - 9 Indoxacarb 144171 - 61 - 9

Butafenacil 134605 - 64 - 4 Deltamethrin-2 (Tralomethrin deg.-2) 52918 - 63 - 5

Etobenzanid 79540 - 50 - 4 Flumiclorac-pentyl 87546 - 18 - 7Cafenstrole 125306 - 83 - 4 Azoxystrobin 131860 - 33 - 8Fenbuconazole 114369 - 43 - 6 Dimethomorph-1 110488 - 70 - 5Cyfluthrin-1 68359 - 37 - 5 Famoxadone 131807 - 57 - 3Cyfluthrin-2 68359 - 37 - 5 Tolfenpyrad 129558 - 76 - 5Cyfluthrin-3 68359 - 37 - 5 Dimethomorph-2 110488 - 70 - 5Cyfluthrin-4 68359 - 37 - 5 Imibenconazole 86598 - 92 - 7Cypermethrin-1 52315 - 07 - 8 Cinidon-ethyl 142891 - 20 - 1Halfenprox 111872 - 58 - 3 Fluthiacet-methyl 117337 - 16 - 6Boscalid 188425 - 85 - 6 Propaquizafop 111479 - 05 - 1Cypermethrin-2 52315 - 07 - 8Cypermethrin-3 52315 - 07 - 8Flucythrinate-1 70124 - 77 - 5Quizalofop-ethyl (Quizalofop-P-ethyl) 76578 - 14 - 8

Cypermethrin-4 52315 - 07 - 8Etofenprox 80844 - 07 - 1Pyridalyl 179101 - 81 - 6Flucythrinate-2 70124 - 77 - 5Silafluofen 105024 - 66 - 6Fluridone 59756 - 60 - 4Thiacloprid 111988 - 49 - 9

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Table S3. Retention indies and MRM transitions of pesticides and internal standards added into Smart Pesticides Database.

Compounds CAS RI a RT b, min MRM-1 (CE) c

QuantifierMRM-2 (CE) c

Qualifier Ratio d, %

PesticidesDEET 134-62-3 1573 9.195 119.1 > 91.1 (10) 119.1>65.1 (25) 45.8Endrin aldehyde 7421-93-4 2300 16.318 249.9 > 214.9 (25) 344.9 > 245 (20) 62.6Endrin ketone 53494-70-5 2461 17.644 316.9 > 101.1 (20) 316.9 > 280.9 (10) 95.8

Internal StandardPhenanthrene-d10 - 1790 11.501 188.2 > 160.1 (25) 188.2 > 158.1 (30) 52.9

Note: a, retention index; b, retention time; c, multiple reaction monitoring (collision energy); d, abundance ratio as MRM-2/MRM-1.

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Table S4. Detection frequencies (DFs) of 123 pesticides in 101 precipitation samples.

Compound DF Compound DF Compound DF

DEET 100% Methoprene 6% Pretilachlor 2%Malathion 96% Fipronil 5% p,p'-DDT 2%Carbaryl 67% Cypermethrin-2 5% Methoxychlor 2%Piperonyl butoxide 63% Xylylcarb 5% Iprodione metabolite 2%Metolachlor 57% Propyzamide 5% Mirex 2%Alachlor 57% Ametryn 5% Thiabendazole 1%Terbacil 48% Isoxathion oxon 5% Bendiocarb 1%Parathion-methyl 46% Pyrethrin I 5% Etridiazole 1%Allidochlor 44% Permethrin-2 5% Methiocarb 1%Bifenthrin 42% XMC 5% Acephate 1%2-Phenylphenol 39% Thiamethoxam deg. 5% Clothianidin 1%Metalaxyl 38% Difenoconazole-1 5% Isoprocarb 1%Diphenylamine 35% Difenoconazole-2 5% α-HCH 1%Clomazone 34% Cypermethrin-3 4% Dimethoate 1%2,6-Dichlorobenzamide 34% Cypermethrin-4 4% Prohydrojasmon-1 1%Chlorothalonil 33% Allethrin-3,4 4% Prohydrojasmon-2 1%Carbetamide 32% Oxadiazon 4% Ethiofencarb 1%Terbutryn 30% Dicloran 4% Propanil 1%Pirimiphos-methyl 25% Propentamphos 4% Spiroxamine-2 1%Diazinon 22% Imazalil 4% Dichlofluanid 1%TCMTB 22% Profenofos 4% Dicofol deg. (DCBP) 1%Chlorpropham 19% Chloridazon 4% Triadimenol-1 1%Metribuzin 18% Propargite-1 4% Butachlor 1%Dimethachlon 17% Boscalid 3% Flutriafol 1%Fenitrothion 17% Methamidophos 3% Chlorfenson 1%Dichlorvos 15% 3-Hydroxycarbofuran 3% Hexaconazole 1%Carbofuran 14% Flutolanil 3% Fludioxonil 1%Propoxur 13% DCIP 3% Tricyclazole 1%Metolcarb 11% EPTC 3% Diclobutrazol 1%Propiconazole-1 10% Tebuthiuron 3% (Z)-Metominostrobin 1%Propiconazole-2 10% Simetryn 3% p,p'-DDD 1%Atrazine 9% Dimethametryn 3% o,p'-DDT 1%Chlorpyrifos 8% Captan 3% Triazophos 1%Fenobucarb 8% Iprodione 3% Benalaxyl 1%Thiometon 8% Dimethomorph-1 3% Endosulfan sulfate 1%Probenazole 7% Etofenprox 2% Nitralin 1%Naled 7% Iprobenfos 2% Resmethrin-2 1%Methidathion 6% Cinmethylin 2% Quizalofop-ethyl 1%Cypermethrin-1 6% Quinalphos 2% Flumioxazin 1%Permethrin-1 6% Mepanipyrim 2% Dimethomorph-2 1%Fenthion 6% Procymidone 2% Imibenconazole 1%

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Table S5. Spearman correlation of detected pesticides in precipitation.

Coefficient (r) DEET Malathion Carbaryl PaM Bifenthrin Alachlor Metolachlor Terbacil Allidochlor

DEET 1.00 0.57*** 0.48*** 0.48*** 0.32* 0.44*** 0.07 0.49*** 0.34*

Malathion 0.57*** 1.00 0.38** 0.33* 0.29 0.15 0.02 0.45** -0.04

Carbaryl 0.48*** 0.38** 1.00 0.79*** 0.09 0.87*** 0.13 0.32 0.35

PaM 0.48*** 0.33* 0.79*** 1.00 0.31 0.87*** 0.03 0.51* 0.04

Bifenthrin 0.32* 0.29 0.09 0.31 1.00 0.02 0.22 0.21 -0.03

Alachlor 0.44*** 0.15 0.87*** 0.87*** 0.02 1.00 0.24 0.17 0.33

Metolachlor 0.07 0.02 0.13 0.03 0.22 0.24 1.00 -0.16 -0.12

Terbacil 0.49*** 0.45** 0.32 0.51* 0.21 0.17 -0.16 1.00 0.52*

Allidochlor 0.34* -0.04 0.35 0.04 -0.03 0.33 -0.12 0.52* 1.00

Diphenylamine 0.53** 0.32 0.39* 0.40 0.16 0.41 -0.12 0.52* 0.83***

BAM 0.46** -0.03 0.47* 0.66** 0.28 0.77*** 0.56** 0.09 0.28

Clomazone 0.15 0.27 0.37 0.44 0.62** 0.08 0.33 0.16 0.20

Carbetamide 0.00 0.37* 0.77* 0.46 0.22 0.40 0.03 -0.02 -0.14

Terbutryn 0.37* -0.09 0.64** 0.74** -0.66** 0.47 -0.14 0.05 0.21

2-Phenylphenol 0.13 -0.01 0.69*** 0.64* -0.41 0.46 -0.15 0.15 0.09

Metalaxyl 0.37* 0.22 0.68*** 0.18 -0.03 0.48* 0.00 0.17 -0.10

Chlorothalonil 0.10 0.11 -0.50 -0.46 0.29 0.38 -0.25 0.12 0.28

PiB 0.41*** 0.36** 0.23 -0.01 0.25 0.00 0.26 0.52*** 0.48**

Note: Spearman correlation: *, p < 0.05; **, p < 0.01; ***, p < 0.001; PiB: piperonyl butoxide; BAM: 2,6-dichlorobenzamide; PaM: parathion methyl.

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Table S5. Continued.

Coefficient (r) Diphenyla-mine BAM Clomazone Carbetamide Terbutryn 2-Phenylphenol Metalaxyl Chlorothalonil PiB

DEET 0.53** 0.46** 0.15 0.00 0.37* 0.13 0.37* 0.10 0.41***

Malathion 0.32 -0.03 0.27 0.37* -0.09 -0.01 0.22 0.11 0.36**

Carbaryl 0.39* 0.47* 0.37 0.77* 0.64** 0.69*** 0.68*** -0.50 0.23

PaM 0.40 0.66** 0.44 0.46 0.74** 0.64* 0.18 -0.46 -0.01

Bifenthrin 0.16 0.28 0.62** 0.22 -0.66** -0.41 -0.03 0.29 0.25

Alachlor 0.41 0.77*** 0.08 0.40 0.47 0.46 0.48* 0.38 0.00

Metolachlor -0.12 0.56** 0.33 0.03 -0.14 -0.15 0.00 -0.25 0.26

Terbacil 0.52* 0.09 0.16 -0.02 0.05 0.15 0.17 0.12 0.52***

Allidochlor 0.83*** 0.28 0.20 -0.14 0.21 0.09 -0.10 0.28 0.48**

Diphenylamine 1.00 0.50 0.20 0.38 0.33 0.16 0.15 -0.54 0.27

BAM 0.50 1.00 0.13 -0.38 0.00 -0.50 1*** 0.45 0.64**

Clomazone 0.20 0.13 1.00 0.29 -0.10 -0.14 -0.22 0.15 0.04

Carbetamide 0.38 -0.38 0.29 1.00 0.04 -0.54 0.43 -0.44 -0.13

Terbutryn 0.33 0.00 -0.10 0.04 1.00 0.84*** 0.19 -0.42 -0.33

2-Phenylphenol 0.16 -0.50 -0.14 -0.54 0.84*** 1.00 0.44 -0.45 -0.13

Metalaxyl 0.15 1*** -0.22 0.43 0.19 0.44 1.00 -0.31 0.37

Chlorothalonil -0.54 0.45 0.15 -0.44 -0.42 -0.45 -0.31 1.00 -0.06

PiB 0.27 0.64** 0.04 -0.13 -0.33 -0.13 0.37 -0.06 1.00

Note: Spearman correlation: *, p < 0.05; **, p < 0.01; ***, p < 0.001; PiB: piperonyl butoxide; BAM: 2,6-dichlorobenzamide; PaM: parathion methyl.

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Figure S1. Occurrence of pesticides in precipitation collected between October 2015 and March 2017.

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