Biotransformation of Tris(2-chloroethyl) Phosphate (TCEP) in Sediment Microcosms and the Adaptation of Microbial Communities to TCEP

Abstract

Tris­(2-chloroethyl) phosphate (TCEP), a typical chlorinated organophosphate ester (OPE), is an emerging contaminant of global concern because of its frequent occurrence, potential toxic effects, and persistence in the environment. In this study, we investigated the microbial TCEP biotransformation and the development of microbial communities in sediment microcosms with repeated TCEP amendments. The TCEP degradation fitted pseudo-zero-order kinetics, with reaction rates of 0.068 mg/(L h) after the first spike of 5 mg/L and 1.85 mg/(L h) after the second spike of 50 mg/L. TCEP was mainly degraded via phosphoester bond hydrolysis, evidenced by the production of bis­(2-chloroethyl) phosphate (BCEP) and mono-chloroethyl phosphate (MCEP). Bis­(2-chloroethyl) 2-hydroxyethyl phosphate (TCEP-OH), phosphoric bis­(2-chloroethyl) (2-oxoethyl) ester (TCEP-CHO), phosphoric acid bis­(2-chloroethyl)­(carboxymethyl) ester (TCEP-COOH), and 2-chloroethyl 2-hydroxyethyl hydrogen phosphate (BCEP-OH) were also identified as microbial TCEP transformation products, indicating that TCEP degradation may follow hydrolytic dechlorination and oxidation pathways. Microbial community compositions in TCEP-amended microcosms shifted away from control microcosms after the second TCEP spike. Burkholderiales and Rhizobiales were two prevalent bacterial guilds enriched in TCEP-amended microcosms and were linked to the higher abundances of alkaline and acid phosphatase genes and genes involved in the metabolism of 2-chloroethanol, a side product of TCEP hydrolysis, indicating their importance in degrading TCEP and its metabolites.

Phosphorus Deficiency Promoted Hydrolysis of Organophosphate Esters in Plants: Mechanisms and Transformation Pathways

“…These results revealed that ACP played a key role in the hydrolysis of OPEs in plant hydroponic systems. It was reported that the AKP and ACP genes were significantly upregulated as a response to tris­(2-chloroethyl) phosphate (TCEP) exposure in the microbial communities of sediments, implying that these two enzymes might participate in the hydrolysis of TCEP . Under P-deficient conditions, prokaryotes, such as algae and microorganisms, could hydrolyze OPEs into inorganic P and used OPEs as the sole P source. , Therefore, with the extension of exposure time, we speculated that the plant could utilize OPEs as the source of P by hydrolyzing them into inorganic P under the pressure of P deficiency.…”

“…12,13 Accumulation of OPEs in humans would cause a threat to human health. 14 Several studies have found that OPEs are likely to transform into other compounds in organisms, such as microorganisms, 15 fish, 16 and humans. 17 Phosphodiesters, the hydrolysis products of OPEs, have been frequently detected in fish 18 and humans, 19 and this evidence indicated that phosphodiester might be the main transformation product of OPEs in organisms.…”

Organophosphate Diesters in Urban River Sediment from South China: Call for More Research on Their Occurrence and Fate in Field Environment

“…The environmental occurrence of di-OPEs is likely related to the fate of tri-OPEs, and therefore, the mechanism of migration and transformation of tri-OPEs to di-OPEs in different environmental matrices, especially under environmental conditions, needs to be fully addressed. Hydrolytic, thermal, photo, and microbial degradation of selected tri-OPE compounds have been investigated, mostly in spiked samples under laboratory controlled conditions. ,− A recent study comprehensively investigated the microbial biotransformation of TCEP and found that microbial TCEP degradation fitted well with pseudo-zero-order kinetics . In addition to BCEP, several other degradation products were identified, including monochloroethyl phosphate, bis (2-chloroethyl) 2-hydroxyethyl phosphate, phosphoric bis (2-chloroethyl) (2-oxoethyl) ester, phosphoric acid bis (2-chloroethyl)­(carboxymethyl) ester, and 2-chloroethyl 2-hydroxyethyl hydrogen phosphate .…”

“…Hydrolytic, thermal, photo, and microbial degradation of selected tri-OPE compounds have been investigated, mostly in spiked samples under laboratory controlled conditions. ,− A recent study comprehensively investigated the microbial biotransformation of TCEP and found that microbial TCEP degradation fitted well with pseudo-zero-order kinetics . In addition to BCEP, several other degradation products were identified, including monochloroethyl phosphate, bis (2-chloroethyl) 2-hydroxyethyl phosphate, phosphoric bis (2-chloroethyl) (2-oxoethyl) ester, phosphoric acid bis (2-chloroethyl)­(carboxymethyl) ester, and 2-chloroethyl 2-hydroxyethyl hydrogen phosphate . It is desirable to illuminate the degradation kinetics and pathways of tri-OPEs with different functional groups under environmental or environment-relevant conditions and to identify degradation products besides di-OPEs.…”

Bioaccumulation, Biotransformation, and Multicompartmental Toxicokinetic Model of Antibiotics in Sea Cucumber (Apostichopus japonicus)

“…For the four BTPs, the errors between theoretical and measured mass were within 3.1 ppm, which is lower than mass accuracy tolerance of 5 ppm. 74 The other three BTPs (ciprofloxacin, N-acetyl-sulfadiazine, and Nacetyl-sulfamethoxazole) were identified with reference standards using the UPLC−MS/MS based on retention time, precursor, and product ions (Table S13). This is the first study to report BTPs of antibiotics in sea cucumber tissues, which is of importance to understand the toxicological effects and conduct risk assessment associated with sea cucumbers.…”