Toxicological effects and biotransformation mechanism of 6:2fluorotelomer carboxylic acid (6:2FTCA) in earthworms (Eisenia fetida)
ZONGYu-lu1, YANG Li-ping2, ZHAO Shu-yan1
1. Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, China; 2. School of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
Abstract：Earthworms (Eisenia fetida) were exposed to the soil spiked with 6:2 fluorotelomeric carboxylic acid (6:2 FTCA) to investigate the toxicological effects and biotransformation mechanisms of 6:2 FTCA in earthworms after in vivo and in vitro exposure. Compared to the controls, no significant effects were observed in malondialdehyde (MDA) contents and peroxidase (POD) activities, while catalase (CAT) activities were increased, and superoxide dismutase (SOD) and glutathione-s-transferase (GST) activities were significantly induced in 6:2 FTCA treatments. This suggested that 6:2 FTCA induced oxidative stress in the earthworm cells. Biodegradation of 6:2 FTCA in the earthworm cytolchrome P450 (CYP450) enzyme extracts and GST enzyme extracts fitted well with the first order kinetics. The biodegradation rate in CYP450 extracts (0.014/h) was much higher than that in GST extracts (0.006/h), indicating CYP450 and GST were involved in the enzymatic transformation and CYP450 contributed more than GST to 6:2 FTCA biotrans formation in earthworms. Three terminal perfluorocarboxylic acid (PFCA) metabolites, including perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA) and perfluorobutanoic acid (PFBA) were observed in the enzyme extracts. The results of gut microbial degradation test showed that aerobic microorganisms contributed to 6:2 FTCA biodegradation in earthworms significantly, and the terminal PFCA metabolites were PFHxA and PFPeA, but anaerobic microorganisms didn't contribute to 6:2 FTCA biotransformation in earthworms.
吴思寒,吴雨濛,王双杰,等.全氟辛烷磺酰胺在小麦和蚯蚓中的富集与转化[J].中国环境科学, 2021,41(5):2434-2440.Wu S H, Wu Y M, Wang S J, et al. Bioaccumulation and biotransformation of perfluorooctane sulfonamide in wheat and earthworms[J]. China Environmental Science, 2021,41(5):2434-2440.
[2]
Wang Z, Cousins I T, Scheringer M, et al. Hazard assessment of fluorinated alternatives to long-chain perfluoroalkyl acids (PFAAs) and their precursors:Status quo, ongoing challenges and possible solutions[J]. Environment International, 2015,75:172-179.
[3]
Sheng N, Zhou X, Zheng F, et al. Comparative hepatotoxicity of 6:2fluorotelomer carboxylic acid and 6:2fluorotelomer sulfonic acid, two fluorinated alternatives to long-chain perfluoroalkyl acids, on adult male mice[J]. Archives of Toxicology, 2017,91(8):2909-2919.
[4]
张宏娜,温蓓,张淑贞.全氟烷基羧酸前体物氟调醇的污染水平与生物转化研究进展[J].环境化学, 2021,40(1):65-82.Zhang H N, Wen B, Zhang S Z. Environmental occurrence and biotransformation of perfluoroalkyl carboxylic acid precursors:Fluorotelomer alcohols[J]. Environmental Chemistry, 2021,40(1):65-82.
[5]
Ellis, David A, Martin, et al. Degradation of fluorotelomer alcohols:A likely atmospheric source of perfluorinated carboxylic acids[J]. Environmental Science& Technology, 2004,38(12):3316-3321.
[6]
Loewen M, Halldorson T, Wang F Y, et al. Fluorotelomer carboxylic acids and PFOS in rainwater from an urban center in Canada[J]. Environmental Science& Technology, 2005,39(9):2944-2951.
[7]
Scott B, Spencer C, Mabury S, et al. Poly and Perfluorinated carboxylates in North American precipitation[J]. Environmental Science& Technology, 2006,40(23):7167-7174.
[8]
Zhao L, Folsom P W, Wolstenholme B W, et al. 6:2 Fluorotelomer alcohol biotransformation in an aerobic river sediment system[J]. Chemosphere, 2013,90(2):203-209.
[9]
Shi G, Cui Q, Pan Y, et al. 6:2fluorotelomer carboxylic acid (6:2FTCA) exposure induces developmental toxicity and inhibits the formation of erythrocytes during zebrafish embryogenesis[J]. Aquatic Toxicology, 2017,190:53-61.
[10]
Zhang, H N, Wen, et al. Determination of fluorotelomer alcohols and their degradation products in biosolids-amended soils and plants using ultra-high performance liquid chromatography tandem mass spectrometry[J]. J CHROMATOGR A, 2015,1404:72-80.
[11]
李琦路,程相会,赵祯,等.黄河中游(渭南-郑州段)全/多氟烷基化合物的分布及通量[J].环境科学, 2019,40(1):228-238.Li Q L, Cheng X H, Zhao Z, et al. Distribution and fluxes of perfluoroalkyl and polyfluoroalkyl substances in the middle reaches of the Yellow River (Weinan-Zhengzhou Section)[J]. Environmental Chemistry, 2019,40(1):228-238.
[12]
Phillips M M M, Dinglasan-Panlilio M J A, Mabury S A, et al. Fluorotelomer acids are more toxic than perfluorinated acids[J]. Environmental Science& Technology, 2007,41(20):7159-7163.
[13]
Mitchell R J, Myers A L, Mabury S A, et al. Toxicity of fluorotelomer carboxylic acids to the algae Pseudokirchneriella subcapitata and Chlorella vulgaris, and the amphipod Hyalella azteca[J]. Ecotoxicology and Environmental Safety, 2011,74(8):2260-2267.
[14]
Qiao W, Miao J, Jiang H, et al. Degradation and effect of 6:2fluorotelomer alcohol in aerobic composting of sludge[J]. Biodegradation, 2021,32(1):99-112.
[15]
Zhang H, Wen B, Huang H, et al. Biotransformation of 6:2fluorotelomer alcohol by the whole soybean (Glycine max L. Merrill) seedlings[J]. Environmental Pollution, 2020,257.
[16]
D'Agostino L A, Mabury S A. Aerobic biodegradation of 2fluorotelomer sulfonamide-based aqueous film-forming foam components produces perfluoroalkyl carboxylates[J]. Environmental Toxicology and Chemistry, 2017,36(8):2012-2021.
[17]
Wang N, Liu J, Buck R C, et al. 6:2Fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants[J]. Chemosphere, 2011,82(6):853-858.
[18]
Zhang S, Lu X, Wang N, et al. Biotransformation potential of 6:2fluorotelomer sulfonate (6:2FTSA) in aerobic and anaerobic sediment[J]. Chemosphere, 2016,154:224-230.
[19]
General C. Test No. 207:Earthworm, Acute Toxicity Tests[J]. Oecd Guidelines for the Testing of Chemicals, 1984,1:1-9.
[20]
Mizukawa H, Nomiyama K, Nakatsu S, et al. Organohalogen compounds in pet dog and cat:Do pets biotransform natural brominated products in food to harmful hydroxlated substances?[J]. Environmental Science& Technology, 2015,50(1):444-452.
[21]
Huang H, Zhang S, Wang S, et al. In vitro biotransformation of PBDEs by root crude enzyme extracts:Potential role of nitrate reductase (NaR) and glutathione S-transferase (GST) in their debromination[J]. Chemosphere, 2013,90(6):1885-1892.
[22]
Zhao S, Liu T, Wang B, et al. Accumulation, biodegradation and toxicological effects of N-ethyl perfluorooctane sulfonamidoethanol on the earthworms Eisenia fetida exposed to quartz sands[J]. Ecotoxicology and Environmental Safety, 2019,181:138-145.
[23]
Zhao S, Liu T, Zhu L, et al. Formation of perfluorocarboxylic acids (PFCAs) during the exposure of earthworms to 6:2fluorotelomer sulfonic acid (6:2FTSA)[J]. Science of the Total Environment, 2021, 760.
[24]
Zhao S, Liang T, Zhu L, et al. Fate of 6:2fluorotelomer sulfonic acid in pumpkin (Cucurbita maxima L.) based on hydroponic culture:Uptake, translocation andbiotransformation[J]. Environmental Pollution, 2019,252:804-812.
[25]
Ramteke, P., W., et al. Isolation of hexachlorocyclohexane (HCH) degrading microorganisms from earthworm gut[J]. Journal of Environmental Science& Health, Part A:Environmental Science& Engineering, 1992,A27(8):2113-2122.
[26]
Verma K, Agrawal N, Farooq M, et al. Endosulfan degradation by a Rhodococcus strain isolated from earthworm gut[J]. Ecotoxicol Environ Saf, 2006,64(3):377-381.
[27]
Zhao S, Wang B, Zhong Z, et al. Contributions of enzymes and gut microbes to biotransformation of perfluorooctane sulfonamide in earthworms (Eisenia fetida)[J]. Chemosphere, 2020,238.
[28]
Guo Y, Liu T, Zhang J, et al. Biochemical and genetic toxicity of the ionic liquid 1-octyl-3-methylimidazolium chloride on earthworms (Eisenia fetida)[J]. Environmental Toxicology and Chemistry, 2016,35(2):411-418.
[29]
Bradford M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal[J]. 1976,72(1/2):248-254.
[30]
Kunze T. Purification and characterization of class alpha and Mu glutathione S-transferases from Porcine Liver[J]. Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology, 1997,116(4):397-406.
[31]
Yang X, Song Y, Ackland M L, et al. Biochemical responses of earthworm Eisenia fetida exposed to cadmium-contaminated soil with long duration[J]. Bulletin of Environmental Contamination& Toxicology, 2012,89(6):1148-1153.
[32]
Jennifer B, Christine B, Barnes C M, et al. Leaching and bioavailability of selected perfluoroalkyl acids (PFAAs) from soil contaminated by firefighting activities[J]. Science of The Total Environment, 2018,646:471-479.
[33]
刘晓玉,国佼,王智,等.栉孔扇贝对8:2FTCA的代谢转化与氧化应激响应[J].中国环境科学, 2021,41(10):4904-4915.Liu X Y, Guo J,Wang Z, et al. Metabolic transformation and physiological response of Chlamys farreri to 8:2fluorotelomer carboxylic acid (8:2FTCA)[J]. China Environmental Science, 2021,41(10):4904-4915.
[34]
刘天琪.6:2氟调磺酸在蚯蚓体内的富集与代谢转化[D].大连:大连理工大学, 2021.Liu T Q. Bioaccumulation and Biotransformation of 6:2Fluorotelomer Sulfonic Acid in Earthworms (Eisenia fetida)[D]. Dalian:Dalian University of Technology, 2021.
[35]
Yu, Byung, Pal. Cellular defenses against damage from reactive oxygen species[J]. Physiological Reviews, 1994,74(1):139-162.
[36]
Cáceres T, Megharaj M, Naidu R. Toxicity and transformation of insecticide fenamiphos to the earthworm Eisenia fetida[J]. Ecotoxicology, 2011,20(1):20-28.
[37]
Liu J, Wang N, Szostek B, et al. 6-2Fluorotelomer alcohol aerobic biodegradation in soil and mixed bacterial culture[J]. Chemosphere, 2010,78(4):437-444.
[38]
Kim M H, Wang N, Chu K H. 6:2Fluorotelomer alcohol (6:2FTOH) biodegradation by multiple microbial species under different physiological conditions[J]. Applied Microbiology& Biotechnology, 2014,98(4):1831-1840.
[39]
陈浩,赵立杰,王宁,等.6:2氟调磺酸在土壤中的有氧微生物转化[J].科学通报, 2019,64(33):3441-3448.Chen H, Zhao L J, Wang N, et al. Aerobic biotransformation of 6:2fluorotelomer sulfonic acid in soil (in Chinese)[J]. Chinese Science Bulletin, 2019,64(33):3441-3448.
[40]
Zhang S, Szostek B, Mccausland P K, et al. 6:2 and 8:2 fluorotelomer alcohol anaerobic biotransformation in digester sludge from a WWTP under methanogenic conditions[J]. Environmental Science& Technology, 2013,47(9):4227-4235.
