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. Author manuscript; available in PMC: 2019 Aug 22.
Published in final edited form as: Chemosphere. 2018 Feb 19;200:133–142. doi: 10.1016/j.chemosphere.2018.02.106

Table 1.

Summary of the selected analytes that were most frequently detected in water samples collected in 2014 and 2015 in the Denver area; n = number of samples; MRL = method reporting limit (ng/L); Med = median concentration (ng/L); Max = maximum concentration (ng/L); LC50 = lowest 50% lethal concentration (μg/L) on indicator fish species (U.S. ECOTOX Knowledgebase); ND = not detected; NA = not applicable; d = day.

Pesticides (Method 1)
2014 (n = 144) 2015 (n = 167)
Analyte Typical use CAS MRL Med Max Frequency Med Max Frequency LC50
Atenolol Beta blocker 29122-68-7 10 104 1850 77.1% 46.8 1150 73.7% 755000a
Caffeine Stimulant 58-08-2 25 111 3760 71.5% 68.2 1390 57.5% 40000b
Carbamazepine Anticonvulsant 298-46-4 10 40.1 390 77.8% 38.5 229 77.2% 16800b
Cotinine Nicotine metabolite 486-56-6 10 22.5 639 61.1% 18.1 120 59.3% NA
DEET Insect repellent 134-62-3 10 56.8 639 91.7% 59.4 3970 92.8% 110000b
Desmethyl-venlafaxine Antidepressant 93413-62-8 10 159 1100 87.5% 148 1280 83.8% NA
Diclofenac Anti-inflammatory 15307-86-5 10 50.3 444 45.1% 26.1 4830 40.1% 70980c
Gabapentin Antiepileptic 60142-96-3 10 682 11 200 97.9% 440 4730 99.4% 8550000d
Gemfibrozil Antihyperlipidemic 25812-30-0 10 50.9 677 49.3% 32.3 409 42.5% 851d
Hydrochlorothiazide Antihypertensive 58-93-5 10 112 819 77.8% 112 1470 82.6% 29774e
Hydroxybupropion Antidepressant 92264-81-8 10 79.8 526 83.3% 67 549 80.8% NA
Hydroxycarbamazepine Anticonvulsant 29331-92-8 10 91.6 652 86.1% 132 993 79.6% NA
Lamotrigine Antiepileptic 84057-84-1 10 258 2390 93.8% 318 2200 93.4% NA
Levorphanol Pain reliever 77-07-6 10 76.2 668 70.1% 41.3 269 54.5% NA
Lidocaine Antiarrhythmic 137-58-6 10 52.1 395 74.3% 58.9 382 73.1% NA
Meprobamate Antianxiety 57-53-4 10 43.8 202 70.1% 36.1 203 68.9% NA
Metformin Antidiabetic 657-24-9 10 343 5450 95.1% 366 7130 100.0% NA
Metoprolol Beta blocker 37350-58-6 10 57.2 499 68.1% 42.4 336 67.1% NA
Oxcarbazepine Anticonvulsant 28721-07-5 10 34.2 267 45.8% 32.5 273 55.7% NA
Oxycodone Pain reliever 76-42-6 10 29.5 126 54.2% 26.6 113 53.3% NA
Phenytoin Antiepileptic 57-41-0 10 27.5 145 51.4% 22.2 130 45.5% 63075d
Pregabalin Antiepileptic 148553-50-8 10 42.0 252 58.3% 42.2 196 53.3% NA
Sotalol Beta blocker 959-24-0 10 32.8 111 59.7% 27.8 122 58.7% NA
Sulfamethoxazole Antibiotic 723-46-6 10 119 727 87.5% 90 772 87.4% 562500a
Temazepam Antianxiety 846-50-4 10 24.4 212 56.3% 29.5 231 42.5% NA
Tramadol Pain reliever 27203-92-5 10 91.1 854 84.0% 81 635 86.2% NA
Triamterene Antihypertensive 396-01-0 10 35.5 1440 52.1% 26.6 1880 50.9% NA
Trimethoprim Antibiotic 738-70-5 10 40.8 633 68.8% 32.9 274 60.5% 3000f
Valsartan Antihypertensive 137862-53-4 10 46.7 483 43.8% 23 292 50.3% NA
Venlafaxine Antidepressant 93413-44-6 10 59.4 481 75.0% 51.1 434 74.3% NA
Waste Indicator Compounds (Method 3)
2014 (n = 144) 2015 (n = 167)
Analyte Typical use CAS MRL Med Max Frequency Med Max Frequency LC50
1,4-Dichlorobenzene Disinfectant 106-46-7 50 192 327 8.3% 104 151 4.2% 1100c
Acetophenone Precursor 98-86-2 50 81.0 520 25.7% 89.8 187 13.8% 155000b
Benzophenone UV blocker 119-61-9 50 91.9 574 21.5% 83.5 288 16.2% 10890b
Bisphenol A Plastic 80-05-7 50 150 923 31.3% 139 705 50.9% 3600b
Butylated hydroxyanisole Food additive 25013-16-5 100 ND ND 0.0% 475 482 44.9% 1000f
Galaxolide Musk 1222-05-5 50 275 3300 65.3% 270 2720 70.1% NA
Phenol Precursor to plastic 108-95-2 50 ND ND 0.0% 90.8 542 33.5% 4000c
Tonalide Musk 21145-77-7 50 125 201 6.9% 84.9 198 19.2% NA
Tri (2-butoxyethyl) Phosphate Flame retardant 78-51-3 50 564 6880 61.8% 978 10100 71.9% NA
Tri (2-chloroethyl) Phosphate Flame retardant 115-96-8 50 113 450 50.0% 113 274 50.9% NA
Tri (dichloroisopropyl) Phosphate Flame retardant 13674-87-8 50 216 956 88.2% 162 773 75.4% NA
Tributyl phosphate Plasticizer 126-73-8 50 178 1730 23.6% 109 602 13.8% 4200f
Triclosan Antibacterial 3380-34-5 50 165 872 18.8% 92.4 430 11.4% 180b
Triethyl citrate Food additive 77-93-0 50 194 1620 51.4% 185 1800 55.7% NA
Triphenyl phosphate Flame retardant 115-86-6 50 73.7 160 22.2% 66.2 120 13.2% 280c
Hormones (Method 3)
2014 (n = 144) 2015 (n = 167)
Analyte Typical use CAS MRL Med Max Frequency Med Max Frequency LC50
17β-Estradiol Estrogen 50-28-2 100 612 1960 5.6% 393 1670 11.4% 0.002a
Estrone Estrogen 53-16-7 100 164 165 0.7% 112 124 1.2% NA
17α-Ethinylestradiol Birth control 57-63-6 100 431 431 0.7% 228 358 9.6% 0.1g
Pesticides (Method 2)
2014 (n = 144) 2015 (n = 167)
Analyte Typical use CAS MRL Med Max Frequency Med Max Frequency LC50
2,4-D Herbicide 94-75-7 10 114 3790 97.9% 73.8 2730 97.6% 5100c
Atrazine Herbicide 1912-24-9 10 28.2 1250 41.0% 14.7 70.3 40.1% 15000b
Bromacil Herbicide 314-40-9 50 80.8 1190 13.2% 74.7 257 10.8% 185000b
Carbaryl Insecticide 63-25-2 10 19.2 154 11.1% 30.1 221 9.0% 5210b
Diuron Herbicide 330-54-1 20 52.4 1310 52.1% 40.6 581 45.5% 14200b
Pesticides (Method 1)
2014 (n = 144) 2015 (n = 167)
Analyte Typical use CAS MRL Med Max Frequency Med Max Frequency LC50
Imidacloprid Insecticide 138261-41-3 20 40.1 339 27.1% 30.2 298 12.6% 194000d
MCPP Herbicide 7085-19-0 20 58.6 976 58.3% 53.6 789 51.5% 10000f
Metolachlor Herbicide 51218-45-2 10 17.3 778 25.7% 22 233 21.6% 8400b
Metolachlor ESA Herbicide 947601-85-6 20 90.0 1040 37.5% 113 742 40.1% NA
Triclopyr Herbicide 55335-06-3 20 47.4 5210 25.0% 38.2 330 16.8% 7500h
a

Japanese medaka (Oryzias latipes) – 4 day exposure.

b

Fathead minnow (Pimephalespromelas) – 2 d exposure.

c

Common carp (Cyprinus carpio) – 4 d exposure.

d

Zebrafish (Danio rerio) – 4 d exposure.

e

Zebrafish (Danio rerio) – 5 d exposure, LC25.

f

Rainbow trout (Oncorhynchus mykiss) – 5 d exposure.

g

Zebrafish (Danio rerio) – 28 d exposure.

h

Rainbow trout (Oncorhynchus mykiss) – 4 d exposure.