Table 2. Risk Screening of Organic Compounds Detected in FPW.
| compound | CAS no. | CMAX, μg/L | predicted CMAX river, μg/L | PNEC, μg/L | assessment factor | RQ | end point |
|---|---|---|---|---|---|---|---|
| Volatile Organic Compounds, μg/L | |||||||
| 1,2,4-trimethylbenzene | 95–63–6 | 400015 | 9.2 | 445 | 100 | 2.3 | reproduction of Daphnia magna, NOEC (21 d) |
| 1,3,5-Trimethylbenzenea | 108–67–8 | 190015 | 4.4 | 445 | 100 | 1.1 | reproduction of Daphnia magna, NOEC (21 d) |
| 2-butanone | 78–93–3 | 24037 | 0.6 | 55 80044 | 1 (SSD) | 0.00001 | |
| acetone | 67–64–1 | 1600037 | 36.7 | 10 60044 | 50 | 0.003 | growth of Microcystis aeruginosa, NOEC (8 d) |
| benzene | 71–43–2 | 530015 | 12.2 | 190044 | 1 (SSD) | 0.006 | |
| benzothiazole | 95–16–9 | <2530 | <0.1 | 1545 | 100 | <0.007 | reproduction of Daphnia magna, NOEC (21 d) |
| bromoform | 75–25–2 | 9.315 | 0.0 | 2947 | 1000 | 0.001 | Lepomis macrochirus, LC50 |
| carbon disulfide | 75–15–0 | 730015 | 16.8 | 1044 | 100 | 1.7 | number of hatched eggs of Danio rerio, NOEC (8 d) |
| chloromethane (methyl chloride) | 74–87–3 | 15015 | 0.3 | 20044 | 1000 | 0.002 | mobility of Daphnia magna, EC50 (48h) |
| ethylbenzene | 100–41–4 | 67036 | 1.5 | 10044 | 10 | 0.02 | reproduction of Ceriodaphnia dubia, NOEC (7 d) |
| isopropylbenzene | 98–82–8 | 16015 | 0.4 | 3544 | 10 | 0.01 | reproduction of Daphnia magna, NOEC (21 d) |
| Methylene Chloride | |||||||
| (dichloromethane) | 75–09–2 | 5.515 | 0.0 | 31044 | 20 (QSAR) | 0.00004 | QSAR case study: prediction of long-term NOEC for Daphnia magna (21 d) |
| n-isopropyltoluene | 99–87–6 | 5415 | 0.1 | 6.546 | 1000 | 0.02 | Daphnia magna, LC50 (48h) |
| toluene | 108–88–3 | 810036 | 18.6 | 68044 | 1 (SSD) | 0.03 | |
| xylene | 1330–20–7 | 650015 | 14.9 | 32744 | 1 (SSD) | 0.05 | |
| Semivolatile Organic Compounds, μg/L | |||||||
| 1,4-dioxane | 123–91–1 | 6037 | 0.1 | 10 00044 | 10 | 0.00001 | mortality of Pimephales promelas, NOEC (32 d) |
| 2-butoxyethanol (EGBE)b | 111–76–2 | 6600051 | 151.5 | 88044 | 100 | 0.2 | growth of Pseudokirchneriella subcapitata, NOEC (72 h) |
| 2,4-dimethylphenol | 105–67–9 | 79037 | 1.8 | 2.1246 | 1000 | 0.9 | Daphnia magna, LC50 (48 h) |
| 2-methylnaphthalene | 91–57–6 | 2000036 | 45.9 | 2.345 | 100 | 20 | reproduction of Daphnia magna, NOEC (21 d) |
| 2-methylphenol (o-cresol) | 95–48–7 | 15037 | 0.3 | 10044 | 10 | 0.003 | mortality of Daphnia magna, NOEC (21 d) |
| 3- and 4-methylphenol (m-cresol and p-cresol) | 17037 | 0.4 | 10044 | 10 | 0.004 | mortality of Daphnia magna, NOEC (21 d) | |
| benzyl alcohol | 100–51–6 | 75015 | 1.7 | 100044 | 50 | 0.002 | reproduction of Daphnia magna, NOEC (21 d) |
| bis(2-ethylhexyl) phthalate (DEHP) | 117–81–7 | 87015 | 2.0 | 0.249 | 1 (SSD) | 10 | |
| butyl benzyl phthalate | 85–68–7 | 11036 | 0.3 | 6.544 | 10 | 0.04 | Pimephales promelas, NOEC (42 d) |
| dimethyl phthalate | 131–11–3 | 1537 | 0.03 | 22044 | 50 | 0.0002 | mortality of Oncorhynchus mykiss, NOEC (102 d) |
| di-n-butyl phthalate | 84–74–2 | 13015 | 0.3 | 1044 | 10 | 0.03 | length of Oncorhynchus mykiss, NOEC (99 d) |
| di-n-octyl phthalate | 117–84–0 | 560030 | 12.9 | 6.446 | 50 | 19 | Daphnia magna, LC50 (48 h) |
| ethylene glycol | 107–21–1 | 5815 | 0.1 | 1000044 | 10 | 0.00001 | growth of Pseudokirchneriella subcapitata, NOEC (72 h) |
| fluorene | 86–73–3 | 40.715 | 0.1 | 0.2546 | 100 | 0.22 | Ictalurus punctatus, LC50 (48 h) |
| naphthalene | 91–20–3 | 140015 | 3.2 | 2.444 | 50 | 1.3 | growth of Oncorhynchus gorbuscha NOEC (40 d) |
| phenanthrene | 85–01–8 | 140036 | 3.2 | 2.5746 | 100 | 65.6 | changes in general physiology of Lepomis macrochirus, EC50 (96 h) |
| phenol | 108–95–2 | 83037 | 1.9 | 844 | 10 | 0.2 | growth of Cirrhina mrigala, NOEC (60 d) |
| propylene glycol | 57–55–6 | 16015 | 0.4 | 260 00044 | 50 | 0.000001 | growth of Ceriodaphnia dubia, NOEC (7 d) |
| pyrene | 129–00–0 | 1315 | 0.03 | 0.62646 | 100 | 0.41 | growth of Daphnia magna, EC50 (24 h) |
| pyridine | 110–86–1 | 260015 | 6.0 | 30044 | 1000 | 0.02 | mobility of Daphnia magna, EC50 (48 h) |
| Nonvolatile Organic Compounds, μg/L | |||||||
| alkyl dimethyl benzyl ammonium chloride (ADBAC)c | 68424–85–1 | >1038 | >0.02 | 0.41548 | 10 | >0.05 | reproduction of Daphnia magna, NOEC (21 d) |
| hexahydro-1,3,5-Trimethyl-1,3,5-triazinane-2-thioned | 59887–80–8 | 150030 | 3.4 | 0.11446 | 1000 | 11.1 | immobilization of Daphnia magna, EC50 (48 h) |
| 2,2,4-trimethyl-1,3-pentanediole | 144–19–4 | 47030 | 1.1 | 10944 | 1000 | 0.01 | growth of Pseudokirchneriella subcapitata, EC50 (72 h) |
a
Compounds with PEC < 1 are highlighted in bold.
b
The maximal concentration of 2-butoxyethanol in the effluent of wastewater treatment plant treating unconventional oil and gas wastewater by combination of settling and chemical precipitation is used as CMAX42
c
ADBAC was detected in 54% of FPW samples at concentrations above the LOD = 10 μg/L38
d
EC50 data for 3,5-dimethyl-1,3,5-thiadiazinane-2-thione (dazomet) were used for PNEC calculation
e
EC50 data for 2,2,4-Trimethyl-1,3-pentanediol diisobutyrate were used for PNEC calculation