Effects of adsorbent carriers in modified ready biodegradability tests of quaternary ammonium salts

Nabeoka, Ryosuke; Kameya, Takashi; Yoshida, Tomohiko; Kayashima, Takakazu

doi:10.1080/10934529.2020.1789410

Cited by 5 publications

(2 citation statements)

References 25 publications

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“…Test guideline 301F has been used for evaluating chemicals in many studies (Seyfried et al 2015; Nabeoka et al 2020). Test guideline 301F can be used to examine the biodegradability of both water‐soluble and poorly water‐soluble materials (Organisation for Economic Co‐operation and Development 1992).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Ready Biodegradability of Biodegradable Plastics

Nabeoka

Suzuki

Akasaka

et al. 2021

Enviro Toxic and Chemistry

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Reducing the environmental burden and assessing the safety of plastics are huge global challenges. However, standard test data on the ready biodegradability of plastics are limited. We evaluated the ready biodegradability of 8 biodegradable plastics using Organisation for Economic Co‐operation and Development (OECD) test guideline 301F with nonspecific bacteria and examined the effects of prolonging the test duration to a maximum of 90 d. Cellulose used as a potential reference material for plastics was not comparable to the reference material of OECD test guideline 301, but it may be improved by using a test concentration lower than the typical test concentration (100 mg/L). Of the 8 plastics examined, polyamide 4, poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate), polycaprolactone, and poly(butylene succinate adipate; PBSA) were biodegraded by >60% by day 28 and considered to show ready biodegradability. Poly(3‐hydroxybutyrate; PHB), poly(3‐hydroxybutyric acid‐co‐3‐hydroxyvaleric acid; PHBV), and poly(butylene succinate; PBS) were biodegraded but did not fulfill the ready biodegradability criteria. Because the typical test concentration is considered to have negative effects on biodegradation and calculation of biodegradation percentage, using a lower concentration may result in PHB, PHBV, and PBS fulfilling the ready biodegradability criteria. Poly(d,l‐lactide; PLA) was not biodegraded. The biodegradation of PBS and PBSA was noted to vary depending on the used inoculum and/or particle size. For the 7 plastics except PLA, the percentage biodegradation on day 60 was larger than that on day 28, indicating that a longer test period could be useful for evaluating the environmental persistence of plastics. In tests in which the plastics were not biodegraded by day 60, no marked biodegradation was observed by day 90. Environ Toxicol Chem 2021;40:2443–2449. © 2021 SETAC

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Section: Introductionmentioning

confidence: 99%

Evaluating the Ready Biodegradability of Biodegradable Plastics

Nabeoka

Suzuki

Akasaka

et al. 2021

Enviro Toxic and Chemistry

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“…For persistence assessments, the degradation can be evaluated in two general ways: by establishing initial low‐level concentrations in the exposure water and then removing the passive dosing medium, or by leaving the passive dosing media in the test system and tracking the loss of substance from the dosing medium, which requires evaluation of the release kinetics from the dosing material (Lee et al, 2014 ; Smith et al, 2012 ; Table 3 ). Reducing the exposure concentrations of substances that are toxic for microbial inocula by applying natural sorbents like clays can help in biodegradation tests to overcome inhibitory effects while enabling the use of nonspecific analyses (Nabeoka et al, 2020 ; Timmer et al, 2020 ). Passive dosing for persistence assessment is not yet included in guidance documents, but has been successfully applied in testing the ecotoxicity of poorly water‐soluble chemicals (OECD, 2019 ).…”

Section: Current and Future Options In Persistence Assessmentmentioning

confidence: 99%

Scientific concepts and methods for moving persistence assessments into the 21st century

Davenport

Curtis-Jackson

Dalkmann

et al. 2022

Integr Envir Assess & Manag

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The evaluation of a chemical substance's persistence is key to understanding its environmental fate, exposure concentration, and, ultimately, environmental risk. Traditional biodegradation test methods were developed many years ago for soluble, nonvolatile, single-constituent test substances, which do not represent the wide range of manufactured chemical substances. In addition, the Organisation for Economic Co-operation and Development (OECD) screening and simulation test methods do not fully reflect the environmental conditions into which substances are released and, therefore, estimates of chemical degradation half-lives can be very uncertain and may misrepresent real environmental processes. In this paper, we address the challenges and limitations facing current test methods and the scientific advances that are helping to both understand and provide solutions to them. Some of these advancements include the following: (1) robust methods that provide a deeper understanding of microbial composition, diversity, and abundance to ensure consistency and/or interpret variability between tests; (2) benchmarking tools and reference substances that aid in persistence evaluations through comparison against substances with well-quantified degradation profiles; (3) analytical methods that allow quantification for parent and metabolites at environmentally relevant concentrations, and inform on test substance bioavailability, biochemical pathways, rates of primary versus overall degradation, and rates of metabolite formation and decay; (4) modeling tools that predict the likelihood of microbial biotransformation, as well as biochemical pathways; and (5) modeling approaches that allow for derivation of more generally applicable biotransformation rate constants, by accounting for physical and/or chemical processes and test system design when evaluating test data. We also identify that, while such advancements could improve the certainty and accuracy of persistence assessments, the mechanisms and processes by which they are translated into regulatory practice and development of new OECD test guidelines need improving and accelerating. Where uncertainty remains, holistic weight of evidence approaches may be required to accurately assess the persistence of chemicals. Integr Environ Assess Manag 2022;1-34.

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