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Pentachlorophenol (PCP) - cadmium (Cd) complex pollution has been identified as a form of persistent soil pollution in south China, exerting detrimental impacts on the indigenous soil bacterial communities. Hence, it is worthwhile to investigate whether and how bacterial populations alter in response to these pollutants. In this study, Escherichia coli was used as a model bacterium. Results showed that PCP exposure caused bacterial cell membrane permeability changes, intracellular ROS elevation, and DNA fragmentation, and triggered apoptosis-like cell death at low exposure concentration and necrosis at high exposure concentration. Cd exposure caused severe oxidative damage and cell necrosis in the tested bacterial strain. The co-exposure to PCP and Cd elevated the ROS level, stimulated the bacterial caspase activity, and induced DNA fragmentation, thereby leading to an apoptosis-like cell death. In conclusion, PCP-Cd complex pollution can cause bacterial population to decrease through apoptosis-like cell death pathway. However, it is worth noting that the subpopulation survives under the complex pollution stress. [Display omitted] • PCP exposure triggered bacterial apoptosis-like cell death and necrosis. • Cd exposure caused severe bacterial oxidative damage and cell necrosis. • The co-exposure caused bacterial oxidative stress and apoptosis-like cell death. • Bacterial cell membrane depolarization can be a potential ultrasensitive indicator. [ABSTRACT FROM AUTHOR]

There is a potential risk to the environment from persistent estrogenic compounds in sewage sludge. In this study, eight bisphenols (BPs) were identified in sewage sludge collected from wastewater treatment plants in 15 cities in China. The estrogenic potencies of the eight BPs and the estrogenic activities of sludge samples were evaluated using a bioluminescence yeast estrogen screen (BLYES) assay. All sludge samples elicited considerable estrogenic activity at a range of 2.8–4.7 ng E2 g −1 dry weight (dw). All BPs exhibited estrogenic activity in the BLYES assay, but there were significant differences between the potency of individual chemicals. Bisphenol AF had the highest activity, followed by tetrachlorobisphenol A, bisphenol F, bisphenol A, bisphenol E, bisphenol S and 2,4-dihydroxybenzophenone. Tetrabromobisphenol A showed weak estrogenic activity at 1 × 10 4 nM, but significant cytotoxicity above this concentration. The total estradiol equivalency quantities (EEQs) of BPs were in the range of 2.16–49.13 pg E2 g −1 dw, accounting for 0.05–1.47% of the total EEQs in sewage sludge samples. The results indicate that BPs made a minor contribution to the estrogenic activity of the investigated sewage sludge. Nevertheless, our results suggest that considerable attention should be directed to the estrogenic potentials of emerging organic pollutants because of their widespread use and their potential to persist in the environment. [ABSTRACT FROM AUTHOR]