title: Degradation kinetics of a potent antifouling agent, butenolide, under various environmental conditions.
abstract: Here, we investigated the degradation kinetics of butenolide, a promising antifouling compound, under various environmental conditions. The active ingredient of the commercial antifoulant SeaNine 211, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), was used as positive control. The results showed that the degradation rate increased with increasing temperature. Half-lives of butenolide at 4 °C, 25 °C and 40 °C were>64 d, 30.5 d and 3.9 d, respectively. Similar half-lives were recorded for DCOIT: >64 d at 4 °C, 27.9 d at 25 °C and 4.5d at 40 °C. Exposure to sunlight accelerated the degradation of both butenolide and DCOIT. The photolysis half-lives of butenolide and DCOIT were 5.7 d and 6.8 d, respectively, compared with 9.7 d and 14.4 d for the dark control. Biodegradation led to the fastest rate of butenolide removal from natural seawater, with a half-life of 0.5 d, while no obvious degradation was observed for DCOIT after incubation for 4 d. The biodegradative ability of natural seawater for butenolide was attributed mainly to marine bacteria. During the degradation of butenolide and DCOIT, a gradual decrease in antifouling activity was observed, as indicated by the increased settlement percentage of cypris larvae from barnacle Balanus amphitrite. Besides, increased cell growth of marine diatom Skeletonema costatum demonstrated that the toxicity of seawater decreased gradually without generation of more toxic by-products. Overall, rapid degradation of butenolide in natural seawater supported its claim as a promising candidate for commercial antifouling industry.
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
authors.forename: Lianguo
authors.initials: L
authors.lastname: Chen
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
authors.forename: Wenxiong
authors.initials: W
authors.lastname: Wang
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region. Electronic address: boqianpy@ust.hk.
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000528:radiation effects / Q000633:toxicity; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D017377:Diatoms / Q000187:drug effects / Q000254:growth & development; D006207:Half-Life; D007700:Kinetics; D007814:Larva / Q000187:drug effects; D010782:Photolysis; D012623:Seawater / Q000382:microbiology; D013844:Thiazoles / Q000378:metabolism / Q000528:radiation effects / Q000633:toxicity; D001468:Thoracica / Q000187:drug effects; D014871:Water Microbiology
chemical_list: D013844:Thiazoles; C080469:Kathon 930; C004511:butenolide; D015107:4-Butyrolactone
keywords: Antifouling; Butenolide; DCOIT; Degradation kinetics; Toxicity