@article {275, title = {Emerging investigator series: nontargeted screening of aryl hydrocarbon receptor agonists in endangered beluga whales from the St. Lawrence Estuary: beyond legacy contaminants.}, journal = {Environ Sci Process Impacts}, volume = {26}, year = {2024}, month = {2024 Sep 18}, pages = {1451-1464}, abstract = {

The elevated concentrations of organohalogen contaminants in the endangered St. Lawrence Estuary (SLE) belugas have prompted the hypothesis that aryl hydrocarbon receptor (AhR) activity may be a contributor towards their potential adverse effects. While indirect associations between AhR and contaminant levels have been reported in SLE beluga tissues, AhR activity was never directly measured. Using bioassays and nontargeted analysis, this study contrasted AhR activity and agonist profiles between pooled tissue extracts of endangered SLE and non-threatened Arctic belugas. Tissue extracts of SLE belugas exhibited significantly higher overall AhR activity than that of Arctic belugas, with a 2000s SLE beluga liver extract exerting significantly higher activity than blubber extracts of SLE and Arctic belugas from the same time period. Contrary to our expectations, well-known AhR agonists detected by nontargeted analysis, including polychlorinated biphenyls (PCBs), were only minor contributors to the observed AhR activity. Instead, Tox21 suspect screening identified more polar chemicals, such as dyes and natural indoles, as potential contributors. Notably, the natural product bromoindole was selectively detected in SLE beluga liver at high abundance and was further confirmed as an AhR agonist. These findings highlighted the significance of the AhR-mediated toxicity pathway in belugas and underscored the importance of novel AhR agonists, particularly polar compounds, in its induction.

}, keywords = {Animals, Beluga Whale, Endangered Species, Environmental Monitoring, Estuaries, Liver, Polychlorinated Biphenyls, Receptors, Aryl Hydrocarbon, Water Pollutants, Chemical}, issn = {2050-7895}, doi = {10.1039/d4em00243a}, author = {Barrett, Holly and Sun, Jianxian and Chen, Yuhao and Yang, Diwen and Verreault, Jonathan and Houde, Magali and Wania, Frank and Peng, Hui} } @article {93, title = {Identification of Chemicals that Cause Oxidative Stress in Oil Sands Process-Affected Water.}, journal = {Environ Sci Technol}, volume = {51}, year = {2017}, month = {2017 Aug 01}, pages = {8773-8781}, abstract = {

Oil sands process-affected water (OSPW) has been reported to cause oxidative stress in organisms, yet the causative agents remain unknown. In this study, a high-throughput in vitro Nrf2 reporter system was used, to determine chemicals in OSPW that cause oxidative stress. Five fractions, with increasing polarity, of the dissolved organic phase of OSPW were generated by use of solid phase extraction cartridges. The greatest response of Nrf2 was elicited by F2 (2.7 {\textpm} 0.1-fold), consistent with greater hydroperoxidation of lipids in embryos of Japanese medaka (Oryzias latipes) exposed to F2. Classic naphthenic acids were mainly eluted in F1, and should not be causative chemicals. When F2 was fractionated into 60 subfractions by use of HPLC, significant activation of Nrf2 was observed in three grouped fractions: F2.8 (1.30 {\textpm} 0.01-fold), F2.16 (1.34 {\textpm} 0.05-fold), and F2.25 (1.28 {\textpm} 0.15-fold). 54 compounds were predicted to be potential chemicals causing Nrf2 response, predominated by SO and O species. By use of high-resolution MS spectra, these SO and O species were identified as hydroxylated aldehydes. This study demonstrated that polyoxygenated chemicals, rather than classic NAs, were the major chemicals responsible for oxidative stress in the aqueous phase of OSPW.

}, keywords = {Animals, Carboxylic Acids, Oil and Gas Fields, Oryzias, Oxidative Stress, Water, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.7b01987}, author = {Sun, Jianxian and Peng, Hui* and Alharbi, Hattan A and Jones, Paul D and Giesy, John P and Wiseman, Steve B} } @article {100, title = {Combined Transcriptomic and Proteomic Approach to Identify Toxicity Pathways in Early Life Stages of Japanese Medaka (Oryzias latipes) Exposed to 1,2,5,6-Tetrabromocyclooctane (TBCO).}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 07 19}, pages = {7781-90}, abstract = {

Currently, the novel brominated flame retardant 1,2,5,6-tetrabromocyclooctane (TBCO) is considered a potential replacement for hexabromocyclododecane (HBCD). Therefore, use of TBCO could increase in the near future. To assess potential toxicological risks to aquatic organisms, embryos of Japanese medaka (Oryzias latipes) were exposed to 10, 100, or 1000 μg/L TBCO from 2 h postfertilization until 1 day post-hatch. TBCO accumulated in embryos in the order of 0.43-1.3 {\texttimes} 10(4)-fold, and the rate constant of accumulation was 1.7-1.8 per day. The number of days to hatch and the hatching success of embryos exposed to the medium and the greatest concentrations of TBCO were impaired. Responses of the transcriptome (RNA-seq) and proteome were characterized in embryos exposed to 100 μg/L TBCO because this was the least concentration of TBCO that caused an effect on hatching. Consistent with effects on hatching, proteins whose abundances were reduced by exposure to TBCO were enriched in embryo development and hatching pathways. Also, on the basis of the responses of transcriptome and proteome, it was predicted that TBCO might impair vision and contraction of cardiac muscle, respectively, and these effects were confirmed by targeted bioassays. This study provided a comprehensive understanding of effects of TBCO on medaka at early life stages and illustrated the power of "omics" to explain and predict phenotypic responses to chemicals.

}, keywords = {Animals, Oryzias, Proteomics, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.6b01249}, author = {Sun, Jianxian and Tang, Song and Peng, Hui* and Saunders, David M V and Doering, Jon A and Hecker, Markus and Jones, Paul D and Giesy, John P and Wiseman, Steve} } @article {104, title = {p,p{\textquoteright}-DDE Induces Gonadal Intersex in Japanese Medaka (Oryzias latipes) at Environmentally Relevant Concentrations: Comparison with o,p{\textquoteright}-DDT.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 Jan 05}, pages = {462-9}, abstract = {

Previous studies have reported high body burdens of dichlorodiphenyltrichloroethane (DDT) and its metabolites in wild fishes worldwide. This study evaluated the adverse effects of 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p{\textquoteright}-DDE) and o,p{\textquoteright}-DDT on gonadal development and reproduction by exposing transgenic Japanese medaka (Oryzias latipes) from hatch for 100 days. While both p,p{\textquoteright}-DDE and o,p{\textquoteright}-DDT induced intersex in male medaka, the lowest observable effective concentration (LOEC) of o,p{\textquoteright}-DDT was 57.7 ng/g ww, about 5-fold lower than that (272 ng/g ww) of p,p{\textquoteright}-DDE. Since LOECs of both chemicals were comparable to the body concentrations in wild fish, DDT contamination would likely contribute to the occurrence of intersex observed in wild fish. Exposure to o,p{\textquoteright}-DDT resulted in much higher expression of vitellogenin in liver of males than p,p{\textquoteright}-DDE, accordant with the higher potency of o,p{\textquoteright}-DDT than p,p{\textquoteright}-DDE to induce intersex. This phenomenon could be partly explained by the significantly elevated levels of 17β-estradiol in plasma of males exposed to o,p{\textquoteright}-DDT, in addition to its estrogenic activity via the estrogen receptor. Significantly lower fertilization (p = 0.006) and hatchability (p = 0.019) were observed in the 13 intersex males. This study for the first time demonstrated the induction of intersex and reproductive effects of p,p{\textquoteright}-DDE and o,p{\textquoteright}-DDT at environmentally relevant concentrations.

}, keywords = {Animals, DDT, Dichlorodiphenyl Dichloroethylene, Disorders of Sex Development, Estradiol, Gonads, Male, Oryzias, Vitellogenins, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.5b05042}, author = {Sun, Jianxian and Wang, Chen and Peng, Hui and Zheng, Guomao and Zhang, Shiyi and Hu, Jianying} } @article {103, title = {Untargeted Screening and Distribution of Organo-Bromine Compounds in Sediments of Lake Michigan.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 Jan 05}, pages = {321-30}, abstract = {

Previously unreported natural and synthetic organo-bromine compounds (NSOBCs) have been found to contribute more than 99\% of total organic bromine (TOB) in environmental matrices. We recently developed a novel untargeted method (data-independent precursor isolation and characteristic fragment, DIPIC-Frag) and identified \~{}2000 NSOBCs in two sediments from Lake Michigan. In this study, this method was used to investigate the distributions of these NSOBCs in 23 surficial samples and 24 segments of a sediment core from Lake Michigan. NSOBCs were detected in all 23 surficial samples and exhibited 10- to 100-fold variations in peak abundance among locations. The pattern of distributions of NSOBCs was correlated with depth of the water column (r(2) = 0.61, p \< 0.001). Hierarchical cluster analysis showed that sediments in close proximity exhibited similar profiles of NSOBCs. Distributions of NSOBCs in 24 segments of a sediment core dated from 1766 to 2008 were investigated, and samples from similar depths exhibited similar profiles of NSOBCs. NSOBCs were grouped into four clusters (soft-cluster analysis) with different temporal trends of abundances. 515 and 768 of the NSOBCs were grouped into cluster 1 and cluster 3 with increasing temporal trends, especially since 1950, indicating that abundances of these compounds might have been affected by human activities.

}, keywords = {Bromine Compounds, Environmental Monitoring, Geologic Sediments, Halogenated Diphenyl Ethers, Hydrocarbons, Brominated, Lakes, Michigan, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.5b04709}, author = {Peng, Hui and Chen, Chunli and Cantin, Jenna and Saunders, David M V and Sun, Jianxian and Tang, Song and Codling, Garry and Hecker, Markus and Wiseman, Steve and Jones, Paul D and Li, An and Rockne, Karl J and Sturchio, Neil C and Giesy, John P} } @article {98, title = {Untargeted Screening and Distribution of Organo-Iodine Compounds in Sediments from Lake Michigan and the Arctic Ocean.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 09 20}, pages = {10097-105}, abstract = {

The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan. Precursor ions and formulas were determined for 2,991 (71\%) of the NSOIC peaks. These compounds exhibited variations in abundances (\<10(3) to \~{}10(7)), m/z values (206.9304-996.9474), retention times (1.0-29.7 min), and number of iodine atoms (1-4). Hierarchical cluster analysis showed that sediments in closer proximity exhibited similar profiles of NSOICs. NSOICs were screened in 10 samples of sediment from the Arctic Ocean to compare the profiles of NSOICs between freshwater and marine sediments. A total of 3,168 NSOIC peaks were detected, and profiles of NSOICs in marine sediments were clearly distinct from Lake Michigan. The coexistence of brominated and iodinated analogues indicated that some NSOICs are of natural origin. Different ratios of abundances of iodinated compounds to brominated analogues were observed and proposed as a marker to distinguish sources of NSOICs.

}, keywords = {Geologic Sediments, Iodine Compounds, Lakes, Michigan, Oceans and Seas, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.6b03221}, author = {Peng, Hui and Chen, Chunli and Cantin, Jenna and Saunders, David M V and Sun, Jianxian and Tang, Song and Codling, Garry and Hecker, Markus and Wiseman, Steve and Jones, Paul D and Li, An and Rockne, Karl J and Sturchio, Neil C and Cai, Minghong and Giesy, John P} } @article {111, title = {Trophic transfer of dechloranes in the marine food web of Liaodong Bay, north China.}, journal = {Environ Sci Technol}, volume = {48}, year = {2014}, month = {2014 May 20}, pages = {5458-66}, abstract = {

Dechloranes are of particular concern because of their ubiquity in environmental matrices, but little is known about their trophic transfer in aquatic food web. This study investigated the trophic transfer of seven dechloranes in a marine food web from Liaodong Bay, China. Dechloranes were determined in sediments and 15 marine species including benthic invertebrates, fish and gulls collected from Liaodong Bay. Biomagnification factors (BMFTL) of dechloranes in black-headed gulls were calculated to be 6.4, 1.7, 0.45, 0.36, 0.14, and 0.11 for mirex, Dechlorane 602 (Dec 602), Dechlorane 603 (Dec 603), antiundecachloropentacyclooctadecadiene (anti-Cl11DP), syn-dechlorane plus (syn-DP), and anti-DP. Significantly positive relationships were found between lipid equivalent concentrations of mirex, Dec 602, and anti-Cl11DP and trophic levels, and the trophic magnification factors (TMFs) were 13, 3.7, and 5.6, respectively, indicating that these compounds undergo trophic magnification in the aquatic food web. Lipid equivalent concentrations of Dec 603 and DP isomers did not exhibit a statistically significant correlation with trophic levels. The relatively low trophic magnification potentials of Dec 603 and DP isomers were possibly due to their extreme hydrophobicity (logKOW: 11.2-11.3) and subsequent low bioavailabilities compared with mirex (7.0), Dec 602 (8.1) and anti-Cl11DP. The results provided important information for understanding the ecological risk of dechloranes.

}, keywords = {Animals, Aquatic Organisms, Bays, Charadriiformes, China, Environmental Monitoring, Fishes, Food Chain, Geologic Sediments, Hydrocarbons, Chlorinated, Invertebrates, Ontario, Regression Analysis, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/es500229y}, author = {Peng, Hui and Wan, Yi and Zhang, Kun and Sun, Jianxian and Hu, Jianying} } @article {121, title = {Molecular and physiological characterization of fluoroquinolone resistance in relation to uropathogenicity among Escherichia coli isolates isolated from Wenyu River, China.}, journal = {Chemosphere}, volume = {87}, year = {2012}, month = {2012 Mar}, pages = {37-42}, abstract = {

Increasing antibacterial resistance and pathogenicity in the environment is of growing concern due to its potential human risk. In the present study, 236 Escherichia coli isolates were collected from Wenyu River in China on drugless (48 isolates) and quinolone-containing plates (189 isolates). Their minimum inhibitory concentrations (MICs) were determined ranging from 0.125 μg mL(-1) to 128 μg mL(-1). Mutation points related to fluoroquinolone resistance were observed at S83 to L and D87 to N or Y in the GyrA subunit and S80 to R or I and E84 to G in the ParC subunit. Generally, MICs of LEV and GAT are dependent on the patterns of these mutation points. The profile with three mutation points was related to LEV-resistant E. coli isolates, and the (S83L, D87N+S80I) mutation profile was most prevalent (65.7\%) in LEV-resistant isolates, while a large proportion of isolates, even those with three mutation points, were susceptive to GAT. The incidence of virulence factors in LEV-resistant isolates (44.7\%, 59/132) was much higher than in nonresistant isolates (23.1\%, 24/104) (χ(2)=11.925, 1{\textdegree} of freedom, p\<0.001) indicating that fluoroquinolone-resistant E. coli would pose a potential risk. A similar distribution was also found in isolates resistant to GAT (χ(2)=7.843, 1{\textdegree} of freedom, p=0.0079).

}, keywords = {Anti-Bacterial Agents, China, Drug Resistance, Bacterial, Escherichia coli, Fluoroquinolones, Rivers, Water Pollutants, Chemical}, issn = {1879-1298}, doi = {10.1016/j.chemosphere.2011.11.050}, author = {Sun, Jianxian and Hu, Jianying and Peng, Hui and Shi, Jiachen and Dong, Zhaomin} }