| Reference | [1]. Sci Total Environ. 2021 May 15;769:144960. doi: 10.1016/j.scitotenv.2021.144960. Epub 2021 Jan 14.<br />
Ecotoxicity and biodegradation of the bacteriostatic 3,3',4',5-tetrachlorosalicylanilide (TSCA) compared to the structurally similar bactericide triclosan.<br />
Gatidou G(1), Chatzopoulos P(2), Chhetri RK(3), Kokkoli A(3), Giannakopoulos A(2), Andersen HR(3), Stasinakis AS(2).<br />
Author information: (1)Water and Air Quality Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, Greece. Electronic address: [email protected]. (2)Water and Air Quality Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, Greece. (3)Department of Environmental Engineering, Technical University of Denmark, Miljøvej 115, Kgs. Lyngby 2800, Denmark.<br />
This article studies the ecotoxicity of 3,3',4',5-tetrachlorosalicylanilide (TCSA) using different bioassays and examines its fate in activated sludge batch experiments. Despite of the common use of TCSA as chemical uncoupler in wastewater treatment systems and as preservative in several products, limited data has been published for its ecotoxicity, while no information is available for its biodegradation. Among different bioassays, the highest toxicity of TSCA was noticed for Daphna magna (48-h LC50: 0.054 mg L-1), followed by Vibrio fischeri (15-min EC50: 0.392 mg L-1), Lemna minor, (7-d EC50: 5.74 mg L-1) and activated sludge respiration rate (3-h EC50: 31.1 mg L-1). The half-life of TSCA was equal to 7.3 h in biodegradation experiments with activated sludge, while use of mass balances showed that 90% of this compound is expected to be removed in an aerobic activated sludge system, mainly due to biodegradation. A preliminary risk assessment of TSCA using the Risk Quotient methodology showed possible ecological threat in rivers where wastewater is diluted up to 100-fold. Comparison with the structurally similar 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan, TCS) showed that both compounds have similar biodegradation potential and seem to cause analogous toxicity to Vibrio fischeri and activated sludge. Specifically, TCS was biodegraded quite rapidly by activated sludge (half-life: 6.2 h), while EC50 values equal to 0.134 mg L-1 and 39.9 mg L-1 were calculated for Vibrio fischeri, and activated sludge respiration rate. Future research should focus on monitoring of TSCA concentrations in the environment and study its effects in long-term toxicity and bioaccumulation tests.<br />
DOI: 10.1016/j.scitotenv.2021.144960 PMID: 33477039 [Indexed for MEDLINE]<br />
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[2]. Int J Environ Res Public Health. 2019 May 14;16(10):1686. doi: 10.3390/ijerph16101686.<br />
Assessment of the Sludge Reduction of the Metabolic Uncoupler 3,3',4',5-tetrachlorosalicylanilide (TCS) in Activated Sludge Culture.<br />
Yang X(1), Xu X(2), Wei X(3), Li J(4), Wan J(5).<br />
Author information: (1)College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 24100, China. [email protected]. (2)College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 24100, China. [email protected]. (3)College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 24100, China. [email protected]. (4)College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 24100, China. [email protected]. (5)College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu 24100, China. [email protected].<br />
Batch experiments were completed to assess the sludge reduction of the metabolic uncoupler 3,3',4',5-tetrachlorosalicylanilide (TCS). The effects of various TCS concentrations on sludge yield were evaluated and the mechanisms associated with sludge reduction were assessed. We discovered that TCS addition resulted in a reduction in sludge. Furthermore, a low dose of TCS (≤3 mg/L) resulted in a slight reduction in the efficiency of the wastewater treatment system, while >3 mg/L TCS reduced matrix removal efficiency, with an especially remarkable inhibition effect on ammonia removal. An increase in TCS addition was associated with a gradual decrease in both the electron transport system (ETS) activity and the specific cellular ATP (SATP) in the TCS system. It was demonstrated that TCS plays an important role in metabolic uncoupling. However, with the addition of TCS, both contents and compositions were increased, and the protein content increased more than polysaccharide production in extracellular polymeric substances (EPS). At TCS concentrations of ≤3 mg/L, DNA content was stable, but it increased rapidly from 4.97 mg/L to 15.34 mg/L as the TCS concentration was elevated from 6 mg/L to 12 mg/L. This implied that the mechanisms of sludge reduction were different for different TCS concentrations, including uncoupling metabolism, maintenance metabolism and lysis-cryptic growth.<br />
DOI: 10.3390/ijerph16101686 PMCID: PMC6571806 PMID: 31091739 [Indexed for MEDLINE]<br />
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[3]. Sci Total Environ. 2019 Dec 1;694:133726. doi: 10.1016/j.scitotenv.2019.133726. Epub 2019 Aug 1.<br />
Changes in the process performance and microbial community by addition of the metabolic uncoupler 3,3',4',5-tetrachlorosalicylanilide in sequencing batch reactors.<br />
Ferrer-Polonio E(1), Fernández-Navarro J(2), Alonso-Molina JL(2), Bes-Piá A(3), Amorós I(2), Mendoza-Roca JA(3).<br />
Author information: (1)Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain. Electronic address: [email protected]. (2)Instituto Ingeniería del Agua y Medio Ambiente, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain. (3)Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.<br />
A complete study about the effects of 3,3',4',5-tetrachlorosalicylanilide (TCS) on organic matter elimination performance, sludge production and on the microbial community of a biological wastewater treatment process has been performed. For this purpose two sequencing batch reactors (SBR) worked in parallel for 43 days with 0.8 mg·L-1 of TCS (SBR-1) and without this metabolic uncoupler (SBR-2). Results indicated that 63.3% of sludge reduction was achieved in SBR-1. However, COD removal efficiency was maintained in similar values in both reactors (89.1% and 92.1% in SBR-1 and SBR-2, respectively). The exhaustive mixed liquor characterization led to know deeply the action mechanism of TCS. In this way, a 69% of adenosine triphosphate (ATP) reduction was observed in SBR-1 in comparison with values measured in SBR-2. On the contrary, an increase in soluble microbial products (SMP) and DNA concentrations occurred as a consequence of TCS addition. Thus, it could be concluded that sludge reduction due to TCS addition was due to both uncoupling effect and cellular lysis. Also, increase in all microbial hydrolytic enzymatic activities measured was observed, which explained the stable performance achieved in SBR-1 despite to the results explained above. It should be highlighted that this uncoupler should not be used in biological treatments that require nitrogen elimination because nitrifying bacteria were affected by its addition (Nitrosomonas and Nitrospira). Finally, the 16S rRNA gene amplicon sequencing informed that an important reduction of bacterial diversity resulted in SBR-1 due to TCS addition.<br />
DOI: 10.1016/j.scitotenv.2019.133726 PMID: 31400674 [Indexed for MEDLINE]<br />
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[4]. Sci Rep. 2015 Jan 23;5:7991. doi: 10.1038/srep07991.<br />
Roles of 3,3',4',5-tetrachlorosalicylanilide in regulating extracellular electron transfer of Shewanella oneidensis MR-1.<br />
Wang YP(1), Yu SS(2), Zhang HL(1), Li WW(3), Cheng YY(2), Yu HQ(2).<br />
Author information: (1)1] Department of Chemistry, University of Science &Technology of China, Hefei, 230026, China [2] China Academy of Engineering Physics, P. O. Box 919, Mianyang 621900, China. (2)Department of Chemistry, University of Science &Technology of China, Hefei, 230026, China. (3)1] Department of Chemistry, University of Science &Technology of China, Hefei, 230026, China [2] Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science &Technology of China, Hefei, 230026, China.<br />
Microbial extracellular electron transfer (EET) is critically involved in many pollutant conversion processes in both natural environment and engineered bioelectrochemical systems (BES), but typically with limited efficiency and poor controllability. In this study, we discover an important role of uncouplers in affecting the microbial energy metabolism and EET. Dose of lower-concentration 3,3',4',5-tetrachlorosalicylanilide (TCS) in the anolyte promoted the current generation and substrate degradation of an MFC inoculated with Shewanella oneidensis MR-1. However, higher TCS dosage caused obvious microbial inhibition. Our results suggest a previously unknown role of uncouplers in regulating the microbial EET. In addition, the underlying mechanisms of such processes are investigated. This work broadens our view about the EET behaviors of microorganisms in real water environment where uncouplers are usually present, and suggests a possible new approach to regulate microbial EET in BES.<br />
DOI: 10.1038/srep07991 PMCID: PMC4303895 PMID: 25612888 [Indexed for MEDLINE]<br />
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[5]. J Invest Dermatol. 1977 Mar;68(3):151-6. doi: 10.1111/1523-1747.ep12492475.<br />
Photoreactions of 3,3',4',5-tetrachlorosalicylanilide with proteins.<br />
Kochevar IE, Harber LC.<br />
The photoreactions of 3,3',4',5-tetrachlorosalicylanilide anion (TCSA-) with two serum proteins were studied. TCSA- and anions of two similar compounds, N-ethyl-3,5-dichlorosalicylamide and salicylanilide, bind noncovalently to human serum albumin (HSA) without irradiation in aqueous pH 7.4 buffered solutions. TCSA- noncovalently bound to HSA yields three types of photoproducts when irradiated with ultraviolet light (lambda greater than 360 nm). A covalently bonded photoadduct between TCSA- and HSA is formed and histidines in HSA are chemically modified. In addition to these two types of photoproducts which involve HSA, two of the four TCSA- photoproducts which form when HSA is absent are also formed when the TCSA-/HSA complex is irradiated. The results presented indicate that not all proteins in the skin are capable of being the carrier protein in photoallergy of TCSA- and that cross reactivity to other halogenated salicylanilides can be explained by further photochemical reactions of TCSA- photoproducts.<br />
DOI: 10.1111/1523-1747.ep12492475 PMID: 14216 [Indexed for MEDLINE]
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