Comparative Developmental Toxicity of New Aromatic Halogenated DBPs in a Chlorinated Saline Sewage Effluent to the Marine Polychaete Platynereis dumerilii

Abstract

Using seawater for toilet flushing may introduce high levels of bromide and iodide into a city's sewage treatment works, and result in the formation of brominated and iodinated disinfection byproducts (DBPs) during chlorination to disinfect sewage effluents. In a previous study, the authors' group has detected the presence of many brominated DBPs and identified five new aromatic brominated DBPs in chlorinated saline sewage effluents. The presence of brominated DBPs in chlorinated saline effluents may pose adverse implications for marine ecology. In this study, besides the detection and identification of another seven new aromatic halogenated DBPs in a chlorinated saline sewage effluent, their developmental toxicity was evaluated using the marine polychaete Platynereis dumerilii. For comparison, the developmental toxicity of some commonly known halogenated DBPs was also examined. The rank order of the developmental toxicity of 20 halogenated DBPs was 2,5-dibromohydroquinone > 2,6-diiodo-4-nitrophenol ≥ 2,4,6-triiodophenol > 4-bromo-2-chlorophenol ≥ 4-bromophenol > 2,4-dibromophenol ≥ 2,6-dibromo-4-nitrophenol > 2-bromo-4-chlorophenol > 2,6-dichloro-4-nitrophenol > 2,4-dichlorophenol > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde > bromoform ≥ 2,4,6-trichlorophenol > 2,6-dibromophenol > 2,6-dichlorophenol > iodoacetic acid ≥ tribromoacetic acid > bromoacetic acid > chloroacetic acid. On the basis of developmental toxicity data, a quantitative structure-activity relationship (QSAR) was established. The QSAR involved two physical-chemical property descriptors (log P and pKa) and two electronic descriptors (the lowest unoccupied molecular orbital energy and the highest occupied molecular orbital energy) to indicate the transport, biouptake, and biointeraction of these DBPs. It can well predict the developmental toxicity of most of the DBPs tested.

Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry

“…Mammalian cell assay has shown that iodoacetic acid is 3 and 288 times more cytotoxic, and 2 and 47 times more genotoxic than bromoacetic acid and chloroacetic acid, respectively (Plewa et al, 2004). Most recently, it has been reported that I-DBPs present significantly higher developmental toxicity and growth inhibition than their brominated or chlorinated DBP analogues (Yang and Zhang, 2013;Liu and Zhang, 2014). Yang et al (2014) investigated toxic impact of bromide and iodide on drinking water disinfection and found that both cytotoxicity and genotoxicity were correlated with total organic iodine (TOI), but not to total organic chlorine (TOCl).…”

Does KMnO4 preoxidation reduce the genotoxicity of disinfection by-products?

“…There may be two reasons for this. One is that after reactions with more chlorine, these intermediate chlorinated aromatic DBPs might decompose to more aliphatic ones, leading to lower toxicity (Li et al, 2015;Liu and Zhang, 2014;Yang and Zhang, 2013). The second reason is that more chlorine promotes the transformation from N-DBPs to C-DBPs.…”

Identification of disinfection by-products (DBPs) halo phenols in drinking water

“…In case of bromate according to both the US and EU, the permissible level is 10 μg/L, and for chlorate and chlorite is 700 μg/L (USEPA 2006). Yang and Zhang (2013) reported the occurrence of brominated haloacetic acids, four new brominated DBPs such as 2,6-dibromo-4-nitrophenol, 2,4,6-tribromophenol, 3,5-dibromo-4-hydroxybenzaldehyde, and 3,5-dibromo-4-hydroxybenzoic acid and 5-bromosalicylic acid in chlorinated saline secondary and primary sewage effluents. Evidences have shown that brominated/iodinated DBPs generally are highly cytotoxic and genotoxic than their chlorinated analogs.…”