Formation potential of disinfection byproducts during chlorination of petroleum hydrocarbon-contaminated drinking water.

Recent leaks of underground fuel storage tanks in the Pearl Harbor region have led to direct release of un-weathered petroleum hydrocarbons (PHCs) into drinking water sources, which then directly underwent chlorination disinfection treatment. Since the control of disinfection byproducts (DBPs) traditionally focuses natural organic matters (NOM) from source water and little is known about the interactions between free chlorine and un-weathered PHCs, laboratory chlorination experiments in batch reactors were conducted to determine the formation potential of DBPs during chlorination of PHC-contaminated drinking water. Quantitative analysis of regulated DBPs showed that significant quantities of THM4 (average 3,498 µg/L) and HAA5 (average 355.4 µg/L) compounds were formed as the result of chlorination of un-weathered PHCs. Amongst the regulated DBPs, THM4, which were comprised primarily of chloroform and bromodichloromethane, were more abundant than HAA5. Numerous unregulated DBPs and a large diversity of unidentified potentially halogenated organic compounds were also produced, with the most abundant being 1,1-dichloroacetone, 1,2-dibromo-3-chloropropane, chloropicrin, dichloroacetonitrile, and trichloracetonitrile. Together, the results demonstrated the DBP formation potential when PHC-contaminated water undergoes chlorination treatment. Further studies are needed to confirm the regulated DBP production and health risks under field relevant conditions.

Qualitative analyses on the classification model of bystander behavior in cyberbullying.

Introduction: Bystanders account for the largest proportion of those involve in cyberbullying and play an important role in the development of cyberbullying incidents. Regarding the classification of bystander behavior in cyberbullying, there exist some limitations in the previous research, such as not considering the complexity of the online environment. Therefore, this study constructed a new classification model of bystander behavior in cyberbullying. Methods: By separately utilizing questionnaires and experimental methods, the study collected participants' behavioral intentions and actual behavioral responses to deal with cyberbullying incidents. Results: Based on two qualitative studies, this study summarized a new classification model, which included three first-level factors and six second-level factors. Specifically, the classification model included positive bystander behavior (i.e., pointing at the victim, bully, and others), neutral bystander behavior (i.e., inaction), and negative bystander behavior (i.e., supporting and excessively confronting the bully). Discussion: The classification model has important contributions to the research on bystander behavior in cyberbullying. This model helps researchers to develop more effective intervention approaches on cyberbullying from the perspective of each category of bystander behavior.

Anaerobic-aerobic biofilm-based digestion of chemical contaminants of emerging concern (CEC) and pathogen indicator organisms in synthetic wastewater.

The efficacy of biofilm based anaerobic-aerobic treatment to reduce caffeine, carbamazepine, and three estrogens (Estrone (E1), 17ß-estradiol (E2), and 17α-ethynylestradiol (EE2)), as well as E. coli (CN-13) and F+ specific coliphage (MS2), from synthetic wastewater was investigated. Results showed no observable reduction of carbamazepine by either anaerobic or aerobic biofilms over a dosing period of 51-days followed by an additional 23 days of observation. Caffeine, by contrast, was reduced by 11.09% in the upflow anaerobic packed bed biofilm reactor (UAnPBBR) and by 91.90% in the aerobic trickling filter biofilm reactor (TF). Estrone (E1) and 17ß-estradiol (E2) showed minimal reduction in the UAnPBBR but 99.67% reduction in the TF, while EE2 was reduced 1.62% in the AnPBBR and 20.36% in the TF. On average, a 3-log reduction of E. coli (CN-13) and a 1-log reduction of F+ specific coliphage (MS2) concentration was observed across the overall reactor system.