Emerging contaminants in wastewater, stormwater runoff, and surface water: Application as chemical markers for diffuse sources.

Diffuse sources of pollution such as sewer leakages, sewer overflows, illicit discharges and stormwater runoff affect the urban surface water quality but often remain unknown. Therefore, the development of chemical markers for identifying and characterizing the origin of diffuse sources of pollution in urban surface waters is a requisite for protecting and managing urban water resources. In this study, the occurrence of 31 emerging contaminants (ECs) in untreated wastewater, treated wastewater, urban stormwater runoff, agricultural stormwater runoff, and freshwater bodies was investigated. Artificial sweeteners (ASs), pharmaceuticals and personal care products (PPCPs) were more frequently detected in the collected water samples. In raw wastewater, 21 target ECs were detected 100% in the collected samples with median concentrations ranging from 49.6 to 77,721 ng/L, while in freshwater bodies, only 13 compounds were found with detection frequency >50%. The median concentration of the majority of detected ECs in freshwater samples was below 100 ng/L. The suitability of ECs as chemical markers of diffuse sources in an urban watershed was assessed using a suite of criteria, including the detection frequency (DF), detection ratio (DR) (i.e. the ratio between median concentration and method quantification limit of a compound) and attenuation rates (i.e., biodegradation, sorption and abiotic degradation) in wastewater treatment processes. In addition, we propose a new key criterion, the concentration ratio (CR) of labile to conservative compounds, to evaluate the applicability of suitable chemical markers for source tracking. Using this new set of criteria (i.e. CR, DF, DR and attenuation rates), our analysis showed that among the investigated ECs, only acesulfame (ACE), acetaminophen (ACT), cyclamate (CYC), saccharin (SAC) were suitable as chemical markers of diffuse sources in surface waters. For caffeine (CF), N,N-diethyl-meta-toluamide (DEET), crotamiton (CTMT), triclocarban (TCC) and triclosan (TCS), their median concentration ratio to sucralose (SUC) in water bodies was consistently higher than that in raw wastewater, suggesting that these compounds might be unsuitable as chemical markers of sewage leakage in surface waters for this study area.

Comments on "Antibiotic pollution in surface fresh waters: Occurrence and effects", Science of the Total Environment, 664, 793-804 (2019).

This article found mistakes and misunderstandings regarding the collection of occurrence data of antibiotics in surface freshwater from the previous literature. These mistakes and misunderstandings were corrected to avoid the propagation of inaccurate information in the scientific literature.

Non-smokers seeking help for smokers: a preliminary study.

OBJECTIVES: To examine the phenomenon of non-smokers spontaneously taking action to seek help for smokers; to provide profiles of non-smoking helpers by language and ethnic groups. SETTING: A large, statewide tobacco quitline (California Smokers' Helpline) in operation since 1992 in California, providing free cessation services in English, Spanish, Mandarin, Cantonese, Korean, and Vietnamese. SUBJECTS: Callers between August 1992 and September 2005 who identified themselves as either white, black, Hispanic, American Indian, or Asian (n = 349,110). A subset of these were "proxies": callers seeking help for someone else. For more detailed analysis, n = 2143 non-smoking proxies calling from October 2004 through September 2005. MAIN OUTCOME MEASURES: Proportions of proxies among all callers in each of seven language/ethnic groups; demographics of proxies; and proxies' relationships to smokers on whose behalf they called. RESULTS: Over 22 000 non-smoking proxies called. Proportions differed dramatically across language/ethnic groups, from mean (+/-95% confidence interval) 2.7 (0.3)% among English-speaking American Indians through 9.3 (0.3)% among English-speaking Hispanics to 35.3 (0.7)% among Asian-speaking Asians. Beyond the differences in proportion, however, remarkable similarities emerged across all groups. Proxies were primarily women (79.2 (1.7)%), living in the same household as the smokers (65.0 (2.1)%), and having either explicit or implicit understandings with the smokers that calling on their behalf was acceptable (90.0 (1.3)%). CONCLUSIONS: The willingness of non-smokers to seek help for smokers holds promise for tobacco cessation and may help address ethnic and language disparities. Non-smoking women in smokers' households may be the first group to target.

Evidence for a new human CYP1A1 regulation pathway involving PPAR-alpha and 2 PPRE sites.

BACKGROUND AND AIMS: Cytochrome P450 1A1 catalyzes the degradation of endobiotics (estradiol, fatty acids, and so on) and the bioactivation of numerous environmental procarcinogens, such as arylamines and polycyclic aromatic hydrocarbons, that are found in food. Several peroxisome proliferators and arachidonic acid derivatives enhance cytochrome P450 1A1 activity, but the mechanisms involved remain unknown. The aim of this work was to study the role of peroxisome proliferator-activated receptors in cytochrome P450 1A1 gene induction. METHODS: The role of peroxisome proliferator-activated receptor transcription factors in cytochrome P450 1A1 induction was assessed by means of enzymatic activities, quantitative real-time polymerase chain reaction, gene reporter assays, mutagenesis, and electrophoretic mobility shift assay. RESULTS: We show that peroxisome proliferator-activated receptor-alpha agonists (WY-14643, bezafibrate, clofibrate, and phthalate) induce human cytochrome P450 1A1 gene expression, whereas 2,4-thiazolidinedione, a specific peroxisome proliferator-activated receptor-gamma agonist, represses it. The induction of cytochrome P450 1A1 transcripts by WY-14643 was associated with a marked increase of ethoxyresorufin O -deethylase activity (10-fold at 200 mumol/L). Transfection of peroxisome proliferator-activated receptor-alpha complementary DNA enhanced cytochrome P450 1A1 messenger RNA induction by WY-14643, although WY-14643 failed to activate xenobiotic responsive element sequences. Two peroxisome proliferator response element sites were located at positions -931/-919 and -531/-519 of the cytochrome P450 1A1 promoter. Their inactivation by directed mutagenesis suppressed the inductive effect of WY-14643 on cytochrome P450 1A1 promoter activation. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay experiments showed that the 2 cytochrome P450 1A1 peroxisome proliferator response element sites bind the peroxisome proliferator-activated receptor-alpha/retinoid X receptor-alpha heterodimer. CONCLUSIONS: We describe here a new cytochrome P450 1A1 induction pathway involving peroxisome proliferator-activated receptor-alpha and 2 peroxisome proliferator response element sites, indicating that peroxisome proliferator-activated receptor-alpha ligands, which are common environmental compounds, may be involved in carcinogenesis.

Serum induces a transcriptional activation of CYP1A1 gene in HepG2 independently of the AhR pathway.

CYP1A1 is largely implicated in carcinogenesis. To date, it is known that this gene is induced by xenobiotics such as polycyclic aromatic hydrocarbons. In this study, we evaluated the effect of serum in the regulation of CYP1A1 gene expression. CYP1A1 mRNA level is induced 1) in HepG2 and HT29-D4 cells by 3-methylcholanthrene 2) only in HepG2 after treatment by serum. The CYP1A1 mRNA induction in HepG2 is the consequence at least in part of a transcriptional activation as was demonstrated by evaluation of the hnRNA level. HepG2 cells were transfected by a plasmid containing the 7.5 Kb of the CYP1A1 promoter and the CAT reporter gene. No CAT stimulation was observed after serum treatment. These results demonstrated that CYP1A1 is induced at a transcriptional level by a physiological compound contained in serum independently of the Ah receptor and the 7.5 Kb promoter region.