Organic Bromine and Iodine Compounds Handbook of Environmental Chemistry

338 Pages·2003·5.91 MB·English

by  Alasdair H. Neilson

Preface
Environmental Chemistry is a relatively young science.Interest in this subject,
however,is growing very rapidly and,although no agreement has been reached
as yet about the exact content and limits ofthis interdisciplinary discipline,there
appears to be increasing interest in seeing environmental topics which are based
on chemistry embodied in this subject.One of the first objectives of Environ-
mental Chemistry must be the study ofthe environment and ofnatural chemical
processes which occur in the environment.A major purpose of this series on
Environmental Chemistry,therefore,is to present a reasonably uniform view of
various aspects of the chemistry of the environment and chemical reactions
occurring in the environment.
The industrial activities of man have given a new dimension to Environ-
mental Chemistry.We have now synthesized and described over five million
chemical compounds and chemical industry produces about hundred and fifty
million tons ofsynthetic chemicals annually.We ship billions oftons ofoil per
year and through mining operations and other geophysical modifications,large
quantities of inorganic and organic materials are released from their natural
deposits.Cities and metropolitan areas ofup to 15 million inhabitants produce
large quantities of waste in relatively small and confined areas. Much of the
chemical products and waste products of modern society are released into the
environment either during production, storage, transport, use or ultimate
disposal.These released materials participate in natural cycles and reactions
and frequently lead to interference and disturbance ofnatural systems.
Environmental Chemistry is concerned with reactions in the environment.It
is about distribution and equilibria between environmental compartments.
It is about reactions, pathways, thermodynamics and kinetics.An important
purpose ofthis Handbook,is to aid understanding ofthe basic distribution and
chemical reaction processes which occur in the environment.
Laws regulating toxic substances in various countries are designed to assess
and control risk of chemicals to man and his environment.Science can con-
tribute in two areas to this assessment; firstly in the area of toxicology and
secondly in the area of chemical exposure. The available concentration
(“environmental exposure concentration”) depends on the fate of chemical
compounds in the environment and thus their distribution and reaction be-
haviour in the environment.One very important contribution ofEnvironmental
Chemistry to the above mentioned toxic substances laws is to develop laboratory
test methods,or mathematical correlations and models that predict the environ-
VIII Preface
mental fate ofnew chemical compounds.The third purpose ofthis Handbook is
to help in the basic understanding and development of such test methods and
models.
The last explicit purpose ofthe Handbook is to present,in concise form,the
most important properties relating to environmental chemistry and hazard
assessment for the most important series ofchemical compounds.
At the moment three volumes ofthe Handbook are planned.Volume 1 deals
with the natural environment and the biogeochemical cycles therein,including
some background information such as energetics and ecology.Volume 2 is con-
cerned with reactions and processes in the environment and deals with physical
factors such as transport and adsorption, and chemical, photochemical and
biochemical reactions in the environment,as well as some aspects of pharma-
cokinetics and metabolism within organisms.Volume 3 deals with anthropogenic
compounds,their chemical backgrounds,production methods and information
about their use, their environmental behaviour, analytical methodology and
some important aspects oftheir toxic effects.The material for volume 1,2 and 3
was each more than could easily be fitted into a single volume, and for this
reason,as well as for the purpose ofrapid publication ofavailable manuscripts,
all three volumes were divided in the parts A and B.Part A ofall three volumes is
now being published and the second part ofeach ofthese volumes should appear
about six months thereafter.Publisher and editor hope to keep materials ofthe
volumes one to three up to date and to extend coverage in the subject areas by
publishing further parts in the future.Plans also exist for volumes dealing with
different subject matter such as analysis,chemical technology and toxicology,
and readers are encouraged to offer suggestions and advice as to future editions
of“The Handbook ofEnvironmental Chemistry”.
Most chapters in the Handbook are written to a fairly advanced level and
should be ofinterest to the graduate student and practising scientist.I also hope
that the subject matter treated will be ofinterest to people outside chemistry and
to scientists in industry as well as government and regulatory bodies.It would
be very satisfying for me to see the books used as a basis for developing graduate
courses in Environmental Chemistry.
Due to the breadth of the subject matter,it was not easy to edit this Hand-
book.Specialists had to be found in quite different areas of science who were
willing to contribute a chapter within the prescribed schedule.It is with great
satisfaction that I thank all 52 authors from 8 countries for their understanding
and for devoting their time to this effort.Special thanks are due to Dr.F.Boschke
ofSpringer for his advice and discussions throughout all stages ofpreparation
of the Handbook.Mrs.A.Heinrich of Springer has significantly contributed to
the technical development ofthe book through her conscientious and efficient
work.Finally I like to thank my family,students and colleagues for being so
patient with me during several critical phases ofpreparation for the Handbook,
and to some colleagues and the secretaries for technical help.
I consider it a privilege to see my chosen subject grow.My interest in Environ-
mental Chemistry dates back to my early college days in Vienna. I received
significant impulses during my postdoctoral period at the University ofCalifornia
and my interest slowly developed during my time with the National Research
Preface IX
Council of Canada, before I could devote my full time of Environmental
Chemistry, here in Amsterdam. I hope this Handbook may help deepen the
interest ofother scientists in this subject.
Amsterdam,May 1980 O.Hutzinger
Twentyone years have now passed since the appearance of the first volumes of
the Handbook.Although the basic concept has remained the same changes and
adjustments were necessary.
Some years ago publishers and editors agreed to expand the Handbook by
two new open-end volume series: Air Pollution and Water Pollution. These
broad topics could not be fitted easily into the headings of the first three vol-
umes.All five volume series are integrated through the choice oftopics and by a
system ofcross referencing.
The outline ofthe Handbook is thus as follows:
1. The Natural Environment and the Biochemical Cycles,
2. Reaction and Processes,
3. Anthropogenic Compounds,
4. Air Pollution,
5. Water Pollution.
Rapid developments in Environmental Chemistry and the increasing breadth of
the subject matter covered made it necessary to establish volume-editors.Each
subject is now supervised by specialists in their respective fields.
A recent development is the accessibility ofall new volumes ofthe Handbook
from 1990 onwards,available via the Springer Homepage http://www.springer.de
or http://Link.springer.de/series/hec/ or http://Link.springerny.com/ series/hec/.
During the last 5 to 10 years there was a growing tendency to include subject
matters of societal relevance into a broad view of Environmental Chemistry.
Topics include LCA (Life Cycle Analysis),Environmental Management,Sustain-
able Development and others.Whilst these topics are ofgreat importance for the
development and acceptance of Environmental Chemistry Publishers and Edi-
tors have decided to keep the Handbook essentially a source ofinformation on
“hard sciences”.
With books in press and in preparation we have now well over 40 volumes
available.Authors,volume-editors and editor-in-chiefare rewarded by the broad
acceptance ofthe “Handbook”in the scientific community.
Bayreuth,July 2001 Otto Hutzinger
Introduction
Except for astatine whose chemistry is largely unknown,fluorine and iodine are
the first and last of the halogens.This is shown in a number of ways including
the successive decrease in the redox potential Hal–/Hal and the electronegativi-
2
ty, and increase in the covalent and van der Waals radii. The substitution of
hydrogen by fluorine does not greatly alter the structure of organofluorines in
contrast to the effect ofintroducing bulky bromine or iodine substituents.
Although fluorides are found abundantly in a range of minerals,the taming of
both elemental fluorine and the hydrogen fluorides presented serious experi-
mental difficulties that were solved only after many years ofdangerous work and
were a prelude to the synthesis oforganofluorines.Bromide is present in seawa-
ter at a concentration of65 ppm and iodide at 0.05 ppm although these concen-
trations are greatly exceeded in hypersaline lakes that are the current source of
bromide and iodide.
The preparation of both elemental bromine and iodine was accomplished
more than 60 years before that ofelemental fluorine,bromine in 1826 and iodi-
ne in 1811’and the synthesis of organobromine and organoiodine compounds
presented fewer problems.A wide range of organofluorines has achieved in-
dustrial importance as refrigerants, surfactants, pharmaceuticals, dyestuffs,
whereas the range oforganobromine and organoiodine compounds in general
use is much more limited.
Organofluorine compounds exist only in the monovalent state whereas all the
other halogens may exist at oxidation levels up to 7.Organoiodine compounds
may exist in the trivalent and pentavalent states that have seen numerous appli-
cations:they have been used extensively in organic synthesis as oxidizing agents
[Zhdankin and Stang 2002],benziodoxoles have attracted attention as synthetic
reagents for the destruction of chemical weapons [Morales-Rojas and Moss
2002] and iodonium salts have been used to develop a silver-free,single-sheet
imaging medium [Marshall et al.2002].
The number of naturally occurring organofluorines is structurally limited
and essentially confined to higher plants in contrast to the plethora oforganob-
romine – and to a lesser extent organoiodine – metabolites produced mostly by
marine biota.Iodide is essential for many biota including humans,and organic
compounds ofiodine have long attracted interest as a result ofthe physiological
importance of iodinated tyrosines in thyroid function and the antiseptic pro-
perty ofdiiodine released from triiodomethane.More recently they have achiev-
ed importance as X-ray contrast agents.
XIV Introduction
Organic compounds of bromine have a greater diversity of application.
Dibromoethane was once used extensively in automobile fuel containing tetrae-
thyl lead to diminish engine corrosion,while methyl bromide has a long history
ofuse as fumigant and has attracted attention as a result ofconcern with global
warming and ozone depletion.In addition,oxidants produced in the bromine
cycle in the troposphere have been shown to be important in mobilizing ele-
mentary Hg to species that are both accessible to biota and accumulate in Arctic
snow [Lindberg et al.2002].Polybrominated aromatic compounds,and especi-
ally diphenyl ethers,have been used as flame-retardants and are now widely dis-
tributed in the environment.A relatively small number ofagrochemicals inclu-
ding bromoxynil,bromacil and bromethuron have been used.
This volume addresses a broad spectrum ofthe environmental issues surro-
unding organic bromine and iodine compounds. In assessing their environ-
mental significance it is important to assess their partition among the environ-
mental compartments and the potential for their long-range dissemination:
these issues are discussed by Cousins and Palm.Orlando discusses atmospheric
chemistry in the context ofozone depletion and global warming,and the signi-
ficant difference between the reactions ofmethyl bromide and methyl iodide are
underscored.
Mammalian toxicity is discussed by DePierre and the mechanisms of their
degradation and transformation by Allard and Neilson.There has been consid-
erable interest in naturally occurring metabolites in the current debate on the
fate and partition of methyl bromide that is – or possibly by the time this is
published was – important nematocide and is produced in substantial quantities
as a metabolite of marine algae.There has also been speculation on the natu-
ral occurrence of diphenyl ethers and Neilson discusses plausible mechanisms
for the biosynthesis ofrepresentative organic bromine and organic iodine me-
tabolites.
Once again,it is a particular pleasure to thank the authors who were prepar-
ed to sacrifice their valuable time and take on the additional burden ofmaking
their contributions.This is particularly appreciated since,in these days ofcon-
tinual stress,potential contributors feel themselves already overburdened with
the demands ofseeking financial support and producing publications to justify
their existence.Any success with this volume is entirely due to the contributors,
and I feel sure that their effort has been well rewarded in producing an exciting
volume.
Lindberg SE,S Brooks,C-J Lin,KJ Scott,MS Landis,RK Stevens,M Goodsite and A Richter
(2002) Dynamic oxidation ofgaseous mercury in the Arctic troposphere at polar sunrise.
Environ Sci Technol 36:1245–1256
Marshall JL,SJ Telfer,MA Young,EP Lindholm,RA Minns,L Takiff(2002) A silver-free,single-
sheet imaging medium based on acid amplification.Science 297:1516-1521
Morales-Royas H and RA Moss (2002) Phosphorolytic reactivity ofo-iodosylcarboxylates and
related nucleophiles.Chem Rev 102:2497–2521
Zdankin VV and PJ Stang (2002) Recent developments in the chemistry ofpolyvalent iodine
compounds.Chem Rev 102:2523–2584
Stockholm,July 2003 Alasdair H.Neilson
The Handbook ofEnvironmental Chemistry Vol.3,Part R (2003):1–74
DOI 10.1007/b11447HAPTER 1
Degradation and Transformation of Organic Bromine
and Iodine Compounds:Comparison with their
Chlorinated Analogues
Ann-Sofie Allard1· Alasdair H.Neilson2
Swedish Environmental Research Institute Limited IVL,Sweden
1 E-mail:[email protected]
2 E-mail:[email protected]
An overview is given of the pathways for the degradation and transformation of selected
brominated and iodinated aliphatic and aromatic compounds.Although greater emphasis is
placed on reactions mediated by microorganisms,examples ofimportant abiotic reactions are
also given.A mechanistic outline ofthe enzymology is provided when possible and compar-
isons are made with the chlorinated analogues which have been more extensively studied.
Keywords. Biodegradation and biotransformation, Abiotic transformation, Aliphatic com-
pounds,Aromatic compounds
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Aliphatic Compounds . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Halogenated Methanes . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 Methyl Halides . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1.1 Methane Monooxygenase Pathway . . . . . . . . . . . . . . . . . 6
2.1.1.2 Methyl Transfer and Corrinoid Pathways . . . . . . . . . . . . . . 8
2.1.1.3 Corrinoid Transmethylations in Aerobic and Anaerobic
Metabolism ofMethyl Halides . . . . . . . . . . . . . . . . . . . . 9
2.1.2 Di- and Trihalomethanes . . . . . . . . . . . . . . . . . . . . . . 12
2.1.2.1 Aerobic Organisms . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1.2.2 Anaerobic Organisms . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Halogenated Alkanes and Related Compounds with Two or More
Carbon Atoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 Halogenated Ethenes . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4 Haloalkanols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.5 Haloaldehydes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.6 Haloalkanoates . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.7 Halogenated Ethers . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.8 Reductive Loss ofHalogen . . . . . . . . . . . . . . . . . . . . . 27
2.9 Brominated and Iodinated Alkanes and Related Compounds
as Metabolic Inhibitors . . . . . . . . . . . . . . . . . . . . . . . 30
3 Abiotic Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.1 Photohydrolytic Reactions . . . . . . . . . . . . . . . . . . . . . 31
3.2 Reductive Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 32
© Springer-Verlag Berlin Heidelberg 2003
2 A.-S.Allard · A.H.Neilson
4 Aromatic Compounds :Aerobic Reactions . . . . . . . . . . . . . 34
4.1 Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.1.1 Degradation and Growth . . . . . . . . . . . . . . . . . . . . . . 34
4.1.2 Metabolism Without Growth . . . . . . . . . . . . . . . . . . . . 35
4.1.3 Biotransformation to Dihydrodiols . . . . . . . . . . . . . . . . . 39
4.2 Benzoates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2.1 Dioxygenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2.1.1 Dehalogenation of2-Halogenated Benzoates . . . . . . . . . . . . 41
4.2.1.2 Loss ofHalogen in 4-Halogenated Phenylacetates . . . . . . . . . 43
4.2.1.3 Halohydrolases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.2.1.4 Reductive Dehalogenation . . . . . . . . . . . . . . . . . . . . . . 45
4.2.1.5 Denitrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.2.1.6 Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.3 Phenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3.1 O-Methylation ofHalogenated Phenols . . . . . . . . . . . . . . . 48
4.3.2 Fungal Metabolism . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.4 Amines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5 Alternative Mechanisms ofDehalogenation . . . . . . . . . . . . 51
5.1 Peroxidase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.2 Dehalogenation by a Polychaete . . . . . . . . . . . . . . . . . . . 51
5.3 Dehalogenation by Thymidylate Synthetase . . . . . . . . . . . . 51
6 Anaerobic Reactions . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.2 Halogenated Hydrocarbons . . . . . . . . . . . . . . . . . . . . . 54
6.2.1 Polyhalogenated Benzenes . . . . . . . . . . . . . . . . . . . . . 54
6.2.2 PCBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.2.3 PBBs and Diphenylmethanes . . . . . . . . . . . . . . . . . . . . 56
6.3 Anaerobic Degradation ofBenzoates . . . . . . . . . . . . . . . . 59
6.3.1 Dehalogenation . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.3.2 Oxidation and Reduction ofAromatic Carboxylates and
Aldehydes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
6.4 Phenols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
7 Concluding Comments . . . . . . . . . . . . . . . . . . . . . . . 61
8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
1
Introduction
In the course ofpreparing this chapter it became evident that relatively few stud-
ies were directed primarily to brominated compounds.Many were concerned
with chlorinated compounds,and some brominated analogues were fortuitously
included.It was therefore necessary to glean the literature on chlorinated com-
Degradation and Transformation of Organic Bromine and Iodine Compounds 3
pounds and extract details on their brominated and iodinated analogues that
were sometimes included.It was then decided to include results for selected chlo-
rinated compounds for several reasons:(i) for comparison with their brominated
analogues;(ii) when studies ofthe brominated compounds were lacking and had
been carried outonlywith the chlorinated analogues;(iii) when studies only with
chlorinated analogues illustrated important principles ofmetabolism.
Attention is drawn to a selection ofreviews that cover various aspects ofde-
halogenation [23,53,55,84,94,162,188,226].
Three different metabolic situations have been encountered:(i) growth at the
expense solely of the brominated compound;(ii) loss of bromide during incu-
bation with cell suspensions or enzymes;(iii) inclusion ofa brominated substrate
in the course of enzymological studies.It is worth noting that for some halo-
genated substrates, evidence for diminution of its concentration has been
demonstrated in spite ofthe absence ofdehalogenation.This may plausibly be at-
tributed to simple biotransformations such as oxidation or dehydrogenation un-
der aerobic conditions.
It is important to note the different experimental procedures that have been
used.Experiments under anaerobic conditions have been carried out under a va-
riety ofconditions using:(i) pure cultures;(ii) metabolically stable mixtures of
organisms;(iii) unselected suspensions ofsoil or sediment.The last can lead to
problems in interpretation since the sample used for assay will generally contain
some ofthe putative degradation products.
A cardinal issue that not been addressed here is the accessibility ofbrominated
compounds – especially hydrocarbons and phenolic compounds – to the appro-
priate organisms in suspended matter or in the sediment phase containing or-
ganic carbon.This is only noted parenthetically with references to some repre-
sentative illustrations from the relevant literature from chlorinated analogues.
Attention is drawn in the text to some taxonomic changes.For simplicity,these
synonymies are duplicated in the table below.
Previous name Current name
Alcaligenes eutrophus Ralstonia eutropha
Flavobacterium sp. Sphingomonas chlorophenolica
Hyphomicrobiumsp.strain CM2 Hyphomicrobium chloromethanicum
Methylobacteriumsp.strain CM4 Methylobacterium chloromethanicum
Pseudomonas cepacia Burkolderia cepacia
Pseudomonas paucimobilis Sphingomonaspaucimobilis
Pseudomonas pickettii Ralstonia pickettii
Rhodococcus chlorophenolicum Mycobacterium chlorophenolicum
Clostridium thermoautotrophica Moorella thermoautotrophica
Enterobacter agglomerans Pantoea agglomerans
For chlorinated compounds,the greatest attention has been given to groups of
substances that are considered environmentally unacceptable,for example,low
4 A.-S.Allard · A.H.Neilson
molecular mass chlorinated aliphatic compounds used as solvents,chiral chloro-
propionates incorporated into agrochemicals,hexachlorocyclohexane,PCBs,and
pentachlorophenol used as a wood preservative.Although brominated organic
compounds are important as agrochemicals,pharmaceuticals and flame-retar-
dants,and iodinated compounds as X-ray contrast agents,these have been stud-
ied less exhaustively than their chlorinated analogues.In addition,the appro-
priate compounds may not be commercially available as substrates and it may
seem unusually academic to synthesize them.
Reliance has ofnecessity been placed on the metabolism ofchlorinated com-
pounds,particularly for the structures of those enzymes that have been deter-
mined by X-ray analysis.Greatest weight has been placed on studies in which the
biochemistry of degradation and transformation has been elucidated,and in
which comparison among the halogens is possible.
There have been major methodological developments during recent years.
These include the success in obtaining crystals of enzymes that enable the ap-
plication ofX-ray analysis to the study ofenzyme mechanisms:these provide im-
portant details and where available the results ofsuch studies have been included.
Although 13C NMR has been used generally with cell suspensions,the availabil-
ity ofon-line LC-NMR opens this to wider application in establishing the struc-
ture oftransient metabolites.There have been substantial advances in establish-
ing the genetics ofdegradation,and procedures for comparing amino acid and
nucleotide sequences among groups ofenzymes.This has made it possible to es-
tablish relationships between enzymes from different organisms and encouraged
speculation on their evolution.This aspect has not,however,been treated here in
the depth that it deserves.
It is worth noting that – with the exception ofsimple bromophenols – virtu-
ally no investigations have been directed to the biodegradation ofthe plethora
of naturally occurring brominated organic compounds that are discussed by
Neilson.
2
Aliphatic Compounds
Introduction
A number ofbrominated alkanes including methyl bromide,1,2-dibromoethane,
1,2-dibromoethene,and propargyl bromide have been used in agriculture as fu-
migants and nematicides. Concern for the adverse effect of these on the de-
struction ofozone and the long half-life ofmethyl bromide has resulted in stud-
ies on their microbial degradation,as well as attempts to quantify their natural
production and the extent to which the ocean serves as a sink.This is discussed
in the chapter by Cairns and Palm and,on the basis of the “replacement prin-
ciple”,attention has been redirected to the use ofpropargyl bromide [248].Poly-
chlorinated ethanes and ethenes have been extensively used as solvent and de-
greasing agents in the metallurgical industry and concern has arisen over their
adverse health effects.This has stimulated efforts to study their degradability and