Table 2. Established Relationships between DBP Species and PARAFAC Components per Disinfection Method and DBP Classa.
| DBP formation potentialb | PARAFAC component(s)c | correlation coefficients (R2)d | ref |
|---|---|---|---|
| Chlorine – Trihalomethanes (THMs) | |||
| trichloromethane (TCM) | hum/ful/m-hum/tyr/tryp/multi | ≥0.71**(5), ≥0.52**(3)/≥0.70** (2)/0.70*, ≥0.61*(2)/0.61*/0.82*, 0.57**/≥0.77*(2) | (16, 18, 68, 69, 73, 84, 85) |
| dibromochloromethane (DBCM) | tyr/tryp | 0.54**/0.50** | (86) |
| TCM, bromodichloromethane (BDCM), DBCM | hum/ful | 0.96*/0.92* | (87) |
| TCM, BDCM, DBCM, tribromomethane | hum/ful/m-hum/tyr/tryp/multi | ≥0.71**(15), ≥0.52*(9)/≥0.70*(4)/0.82*, 0.66*/0.95, 0.67**/0.84**, ≥0.52 (5)/0.95, 0.69** | (51, 63, 67, 69, 84, 88−95) |
| Chlorine Dioxide – THMs | |||
| TCM | hum | ≥0.92 (4) | (96) |
| Ozone – THMs | |||
| TCM | multi | 0.91** | (97) |
| BDCM | multi | 0.90** | (97) |
| Chlorine – Haloacetic Acids (HAAs) | |||
| dichloroacetic acid (DCAA) | hum/ful/multi | 0.58**/≥0.53**(2)/0.61** | (18, 98) |
| trichloroacetic acid (TCAA) | hum/ful/multi | 0.73**, 0.52**/0.68**(2)/0.70** | (18, 98) |
| monochloroacetic acid (MCAA), DCAA, TCAA | hum/m-hum/tyr/tryp/multi | ≥0.73*(4), ≥0.51 (2)/0.64*/0.71*/0.87*/0.91* | (73, 93) |
| DCAA, TCAA, bromochloroacetic acid (BCAA) | hum/ful | 0.93*/0.89* | (87) |
| DCAA, TCAA, dibromoacetic acid (DBAA) | hum/multi | 0.72**, 0.67**/≥0.69**(2) | (78) |
| MCAA, DCAA, TCAA, monobromoacetic acid (MBAA), DBAA | hum/tyr/tryp/multi | ≥0.81**(4), ≥0.55 (2)/≥0.82(2)/0.74/≥0.83 (2) | (17, 76, 88, 92, 94) |
| MCAA, DCAA, TCAA, BCAA, MBAA, DBAA | hum/m-hum/tryp | ≥0.71**(2), 0.65*/≥0.56*(2)/0.54* | (91, 99) |
| MCAA, DCAA, TCAA, MBAA, DBAA, tribromoacetic acid, BCAA, bromodichloroacetic acid, dibromochloroacetic acid | hum | 0.71 | (92) |
| Ozone – HAAs | |||
| DCAA | multi | 0.90** | (97) |
| UV + Chlorine – HAAs | |||
| DCAA | tyr | 0.57** | (100) |
| TCAA | tyr | 0.64** | (100) |
| Chlorine – Haloketones (HKs) | |||
| 1,1-dichloro-2-propanone (DCP) | hum/tyr/tryp | ≥0.86**(2), ≥0.52**/0.54**/0.60** | (101, 102) |
| 1,1,1-trichloro-2-propanone (TCP) | hum/ful/tryp | ≥0.71*(5), ≥0.56 (3)/0.81*/0.72** | (87, 93, 102) |
| DCP, TCP | hum/m-hum/tyr/tryp/multi | ≥0.72*(2)/0.71*/0.71*/0.76*/0.86* | (63, 73) |
| Chlorine – Haloacetaldehydes (HALs) | |||
| 2,2,2-trichloroethane-1,1-diol (chloral hydrate) | hum/ful/tyr/multi | ≥0.72*(6), ≥0.50**(2)/0.52**/0.77**/0.78** | (51, 93, 94, 98) |
| UV + Chlorine – HALs | |||
| chloral hydrate | hum/tryp | ≥0.96 (4)/≥0.95 (4) | (22) |
| Chlorine – Halogenated Furanones (X-Furanones) | |||
| 4-chloro-3-dichloromethyl-2H-furan-5-one | hum | ≥0.70*(3) | (103) |
| Monochloramine – Iodinated DBPs (I-DBPs) | |||
| dichloroiodomethane, bromochloroiodomethane, dibromoiodomethane, chlorodiiodomethane, bromodiiodomethane, triodomethane | index | ≥0.96 (2) | (62) |
| Chlorine – Carbonaceous Disinfection Byproducts (C-DBPs) | |||
| monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, TCM, DCP, TCP | hum/m-hum/tyr/tryp/multi | 0.78*/0.70**/0.72*/0.88*/0.92* | (73) |
| TCM, BDCM, DBCM, TBM, dichloroacetic acid, trichloroacetic acid, dibromoacetic acid | hum/multi | ≥0.62**(2)/≥0.62**(2) | (78) |
| Chlorine – Halonitromethanes (HNMs) | |||
| trichloronitromethane (chloropicrin) | hum/m-hum/tyr/tryp/multi | ≥0.73*(4)/0.75*/≥0.71*(2)/≥0.80*(2), 0.65**/0.85* | (51, 63, 73, 89) |
| Chlorine – Haloacetonitriles (HANs) | |||
| bromochloroacetonitrile | hum/m-hum/tyr/tryp | 0.76**/0.79**/0.59**/0.57** | (86) |
| dichloroacetonitrile | hum/tyr/tryp | ≥0.83*(3), 0.60/0.52**/0.66** | (93, 102) |
| dichloroacetonitrile, bromochloroacetonitrile | hum/ful | 0.90*/0.85* | (87) |
| dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, dibromoacetonitrile | hum/tyr/tryp/multi | 0.55/≥0.6 (2)/≥0.85**(3), 0.64/0.73** | (51, 63, 89, 94) |
| dichloroacetonitrile, trichloroacetonitrile | hum/m-hum/tyr/tryp/multi | 0.56*/0.64*/0.64*/0.78*/0.80* | (73) |
| Monochloramine – N-Nitrosamines (NAs) | |||
| N-nitrosodiphenylamine (NDPhA) | hum/index | 0.6/0.6 | (104) |
| N-nitrosomorpholine | index | 0.55 | (104) |
| UV + Monochloramine – Cyanide (CNX) | |||
| cyanogen chloride | hum/tryp | 0.91/0.79 | (22) |
| Chlorine – Nitrogenous Disinfection Byproducts (N-DBPs) | |||
| dichloroacetonitrile, bromochloroacetonitrile | hum/m-hum | 0.50**/0.62** | (86) |
| trichloronitromethane, trichloroacetonitrile, dichloroacetonitrile | hum/m-hum/tyr/tryp/multi | 0.77*/0.80*/0.78*/0.86*/0.94* | (73) |
This table is a summary of data extracted from the 45 selected articles (complete data fields are provided in SI, Extracted Data as a TXT file). Established (linear) relationships for similar DBP species and disinfection methods are separated by a forward slash.
Reported DBP and chemical disinfection method employed.
Identified PARAFAC components classified by excitation–emission wavelength pairs into common environmental fluorescence regions (reported in Table 1), where hum, ful, m-hum, tyr, and tryp refer to humic, fulvic, microbial-humic, tyrosine, and tryptophan-like fluorophores, respectively. In addition, “multi” and “index” refer to relationships derived using multiple linear regression models or sum of PARAFAC components and component indices, e.g., humic-like divide by tryptophan-like, respectively.
Strong linear relationships (R2 ≥ 0.7) and moderate linear relationships (R2 ≥ 0.5–0.7) between similar DBPs species and PARAFAC components are differentiated by a comma. Number of established relationships are expressed in parentheses; * and ** indicate p-values of ≤0.05 and ≤0.01, respectively. In the case of several significant relationships, only the highest p-value is reported.