Person:
Claßen, Daniela

Profilbild
E-Mail-Adresse
Geburtsdatum
Forschungsvorhaben
Organisationseinheiten
Logo der Organisationseinheit
Organisationseinheit
Berufsbeschreibung
Biologin
Gymnasiallehrerin
Nachname
Claßen
Vorname
Daniela
Name

Filter

2021 - 20222
Filter zurücksetzen

Einstellungen

Autor:in: Ackermann, Juliane × Anfangsdatum: 2020 ×

Suchergebnisse

Gerade angezeigt 1 - 2 von 2
  • Vorschaubild nicht verfügbar
    Veröffentlichung
    Fate of 14C-labelled ionic organic chemicals in a water-sediment system and surface water
    (2022) Holzmann, Hannah; Ackermann, Juliane; Claßen, Daniela
    The persistence assessment of organic chemicals is based on neutral reference substances. Therefore, our study aimed at investigating the influence of a chemical charge on the degradation of organic compounds in a water-sediment system (OECD 308) and surface water (OECD 309). We used radiolabelled 4-n-dodecylbenzenesulfonic acid sodium salt (14C-DS-, anionic), 4-n-dodecylbenzyltrimethylammonium chloride (14C-DA+, cationic) and 4-n-dodecylphenol (14C-DP, non-ionic) which are structurally similar except their charges. After 120 days of incubation in a water-sediment system, 68% (14C-DS-), 6% (14C-DA+) and 63% (14C-DP) of the applied radioactivity (AR) were mineralized. The formation of non-extractable residues (NER) after 120 days was highest for 14C-DA+ (33% AR), followed by 14C-DS- (19% AR) and 14C-DP (14% AR). Dissipation half-lives (DT50) at 12 ˚C decreased as follows: 14C-DA+ (346 days) >> 14C-DS- (47 days) > 14C-DP (30 days). After 60 days of incubation in surface water with suspended sediment, mineralization of 14C-DS-, 14C-DA+ and 14C-DP accounted for 63%, 7% and 58% AR, respectively. Highest NER formation was observed for 14C-DP (21% AR), followed by 14C-DA+ (14% AR) and 14C-DS- (9% AR). DT50 (12 ˚C) decreased as follows: 14C-DA+ (45 days) > 14C-DP (3 days) > 14C-DS- (2 days). We showed that a positive charge reduces the degradability of organic chemicals in both test systems. From a scientific point of view, simulation studies following OECD 309 should always be complimented by tests with high sorption capacity, e.g. OECD 308 and OECD 307 tests in order to assess the degradation of a compound, especially in case of cationic organic compounds. © 2022 The Authors
  • Vorschaubild nicht verfügbar
    Veröffentlichung
    Fate and behavior of 14C-labelled ionic compounds in a soil simulation test
    (2021) Ackermann, Juliane; Claßen, Daniela; Schäffer, Andreas
    The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodium salt (14C-D-) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenylring-14C(U)] (14C-DA+). They were investigated in a soil simulation study according to the OECD 307 test guideline by measuring the distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) in one soil after 0, 1, 7, 14, 49, 84 and 124 days of incubation. Extractable portions of 14C were examined by means of radio-TLC and -HPLC analyses. Microbial activity of the soil incubated with and without 14C-DP, 14C-DS- and 14C-DA+ was determined measuring the reduction of dimethylsulfoxide (DMSO) over time. After 124 days of incubation highest mineralization could be observed for 14C-DS- (64.5% AR). Except CO2, no volatile residues were formed over time. Besides the parent compounds, polar (14C-DP, 14C-DS- and 14C-DA+) and nonpolar (14C-DA+) transformation products were detected. Highest amounts of 14C were extracted using methanol and were thus potentially bioavailable for soil microorganisms. Microbial activity was markedly higher in soil incubated with 14C-DP and 14C-DS- compared to 14C-DA+ or soil without any treatment. Half-lives (DT50 k2) at 18 ËÌC were as follows: DA+ (61.8 days) > DS- (18.2 days) > DP (10.0 days). In case of the cationic compound and its transformation products we conclude that a higher sorption affinity to soil particles leads to reduced bioavailability for microorganisms and thus reduced mineralization resulting in a higher persistence compared to anionic and non-charged organic compounds in soil. The impact of our findings on the persistence assessment of chemicals when performing OECD guideline tests in soil, water-sediment and surface water is discussed. © 2021 Published by Elsevier B.V.