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Tracking biotransformation of hexachlorocyclohexane isomers by compound specific isotope analysis

English title Tracking biotransformation of hexachlorocyclohexane isomers by compound specific isotope analysis
Applicant Kohler Hans-Peter
Number 153534
Funding scheme Project funding (Div. I-III)
Research institution Eawag
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Other disciplines of Environmental Sciences
Start/End 01.07.2014 - 30.06.2018
Approved amount 279'696.00
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All Disciplines (3)

Discipline
Other disciplines of Environmental Sciences
Experimental Microbiology
Biochemistry

Keywords (5)

Hexachlorocyclohexane (HCH); Compound-specific isotope analysis (CSIA); Biotransformation; Haloalkane dehalogenase (LinB); Dehydrochlorinase (LinA)

Lay Summary (German)

Lead
Lindan (gamma-Hexachlorcyclohexan) ist ein Organochlorpestizid, das als Schädlingsbekämpfungsmittel früher in der Schweiz produziert und eingesetzt wurde. Bei der Produktion sind unerwünschte Nebenprodukte angefallen, welche oft unsachgemäss entsorgt wurden und darum heute noch immer grosse Umweltprobleme darstellen. In diesem Projekt untersuchen wir die Biotransformation von Lindan und verwandten Verbindungen mit isotopischen Methoden, um einen Beitrag zur Risikoabschätzung verunreinigter Standorte zu leisten.
Lay summary

Einzelstoffisotopenanaylse ist eine neuartige analytische Methode, mit welcher Isotopenverhältnisse natürlich vorkommender Isotopen in Umweltchemikalien bestimmt werden können. Diese Information kann gebraucht werden, um potentielle Schadstoffquellen zu ermitteln und das Ausmass biologischer Abbauvorgänge zu bestimmen.

 

In diesem Projekt wenden wir die Methode der Einzelstoffisotopenanaylse an, um mikrobielle Transformationsreaktionen von Lindan und dessen Isomeren zu untersuchen. Dazu werden wir eine neue Methode zur Bestimmung von Chlorisotopen entwickeln. Diese Methode werden wir zuerst auf enzymatische Umsetzungen von Lindan und dessen Isomeren anwenden, um die für spätere Feldversuche nötigen Grundlagen zu erarbeiten.

 

Das Projekt befasst sich einerseits mit Grundlagenforschung bei der Methodenentwicklung zur Messung von Chlorisotopenverhältnisse in chlororganischen Schadstoffen und der Enzymatik des Lindanabbaus. Andererseits, planen wir die erarbeitete Methode im Feld anzuwenden, um den Abbau von Lindan in verunreinigten Standorten nachzuweisen und zu quantifizieren.

 

Direct link to Lay Summary Last update: 26.09.2014

Responsible applicant and co-applicants

Employees

Name Institute

Collaboration

Group / person Country
Types of collaboration
Dr. Agnieszka Dybala-Defratyka / Lodz University of Technology Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Rup Lal / University of Dehli India (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Interfaces against pollution - IAP Poster Assessing the biotransformation of hexachlorocyclohexane-isomers by compound-specific isotope analysis 10.06.2018 La Grande Motte, France Hofstetter Thomas; Kohler Hans-Peter; Schilling Iris;
IBP PhD congress (Zürich) Poster Carbon and hydrogen kinetic isotope effects of enzymatic transformation reactions of hexachlorocyclohexane 06.04.2018 Zürich, Switzerland Schilling Iris; Kohler Hans-Peter; Hofstetter Thomas;
Isotopes 2017 Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 09.07.2017 Monte Verita, Switzerland Kohler Hans-Peter; Hofstetter Thomas; Schilling Iris;
IBP PhD congress (Zürich) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 21.04.2017 Zürich, Switzerland Hofstetter Thomas; Kohler Hans-Peter; Schilling Iris;
SCS Fall Meeting 2016 Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 15.09.2016 Zürich, Switzerland Kohler Hans-Peter; Hofstetter Thomas; Schilling Iris;
SGM (Schweizerisch Mikrobiologische Gesellschaft) Annual assembly (Bern) Talk given at a conference Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 14.06.2016 Bern, Switzerland Schilling Iris; Hofstetter Thomas; Kohler Hans-Peter;
SGM (Schweizerisch Mikrobiologische Gesellschaft) Annual assembly (Bern) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 01.04.2016 Bern, Switzerland Kohler Hans-Peter; Hofstetter Thomas; Schilling Iris;
IBP PhD congress (Zürich) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 01.04.2016 Zürich, Switzerland Kohler Hans-Peter; Schilling Iris; Hofstetter Thomas;
Jahrestagung der Arbeitsgemeinschaft Stabile Isotope (ASI) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis28 28.09.2015 Heidelberg, Germany Hofstetter Thomas; Schilling Iris; Kohler Hans-Peter;
Bi-annual Isotopes Conference Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 21.06.2015 Jerusalem, Israel Hofstetter Thomas; Schilling Iris; Kohler Hans-Peter;
SGM (Schweizerisch Mikrobiologische Gesellschaft) Annual assembly (Lugano) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 28.05.2015 Lugano, Switzerland Schilling Iris; Hofstetter Thomas; Kohler Hans-Peter;
IBP PhD congress (Zürich) Poster Tracking biotransformation of hexachlorocyclohexanes by compound-specific isotope analysis 10.04.2015 Zürich, Switzerland Hofstetter Thomas; Schilling Iris; Kohler Hans-Peter;


Associated projects

Number Title Start Funding scheme
172950 Biodegradation of organic pollutants by mono- and dioxygenation: Insights into rates and mechanisms from isotope effects of oxygen activation and substrate oxygenation 01.03.2018 Project funding (Div. I-III)
141805 Assessment of micropollutant degradation using multi-element compound-specific isotope analysis 01.07.2013 Sinergia
139111 Expanding Compound-Specific Isotope Analysis Towards Polar Organic Micropollutants and Chlorine Isotopes 01.09.2012 R'EQUIP

Abstract

gamma-Hexachlorocyclohexane (gamma-HCH) is an organochlorine pesticide that was extensively used during the last century as an insecticide for the control of agricultural pests and vector borne diseases. It was mainly used in two ways. First, as a technical mixture mainly containing the five isomers alpha-HCH (60-70%), beta-HCH (5-12%), gamma-HCH (10-12%), delta-HCH (6-10%) and epsilon-HCH (2-3%) and later as lindane (gamma-HCH, 99%). In-discriminate agricultural application of technical HCH and inadequate disposal of isomeric waste from lindane production led to widespread contamination of agricultural soils and production landfills with these HCH isomers. It has been estimated that between 1.7 and 4.8 million tons of HCH residuals is still present worldwide. These numbers illustrate that the environmental burden of HCH wastes still consti-tutes an immense environmental problem and consequentially, various HCH isomers were recently add-ed to the list of persistent organic pollutants regulated under the Stockholm convention.Biodegradation and bioremediation are paramount processes to destroy HCH isomers in the en-vironment and several studies have shown that bioaugmentation and biostimulation approaches have a promising potential for remediating low-level HCH-contaminations in agricultural environments. However, there are open questions to be answered with regard to the fate of the various HCH isomers, the mechanisms governing HCH isomer turnover, and in particular the methodology for assessing success of HCH-turnover in environmental settings, before such bioremediation approaches can be unconditionally promoted for use in large scale field applications. In this context, compound-specific isotope analysis (CSIA) offers unique opportunities to assess both the extent and the pathways of HCH biotransformation.In this project, we will address these research questions by developing and applying CSIA meth-ods for Cl- and C-isotope analysis of HCH isomers. To this end, we will extend current analytical methods for Cl isotope analysis and apply them to elucidate the unknown kinetic isotope effects associated with HCH biotransformation under oxic conditions. The fundamental understanding of the enzymatic dehy-drochlorination and nucleophilic substitution reactions will enable us to evaluate isotope fractionation in HCH isomers and their transformation products to assess the extent and predominant pathways of deg-radation. With this information, we finally plan to assess the extent of HCH degradation in soil samples from contaminated sites.
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