EPA-670/2-75-005
January 1975 Environmental Protection Technology Series
DEGRADATION MECHANISMS:
CONTROLLING THE BIOACCUMULATION OF
HAZARDOUS MATERIALS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-670/2-75-005
January 1975
DEGRADATION MECHANISMS: ,
CONTROLLING THE BIOACCUMULATION
OF HAZARDOUS MATERIALS
By
Charles J. Rogers
Robert E. Landreth
Solid and Hazardous Waste Research Laboratory
Program Element No. 1DB311
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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REVIEW NOTICE
The National Environmental Research Center—Cincinnati
has reviewed this report and approved its publication.
Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
ii
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FOREWORD
Man and his environment must be protected from the
adverse effects of pesticides, radiation, noise and other
forms of pollution, and the unwise management of solid waste.
Efforts to protect the environment require a focus that recognizes
the interplay between the components of our physical environ-
ment—air, water, and land. The National Environmental Research
Centers provide this multidisciplinary focus through programs
engaged in
• studies on the effects of environmental contaminants
on man and the biosphere, and
• a search for ways to prevent contamination and to
recycle valuable resources.
As a part of these activities, the study described here
documents the existence of natural hazardous waste transformation
processes in the environment and the need for implementation of
control technology.
A. W. Breidenbach, Ph.D.
Director
National Environmental
Research Center, Cincinnati
m
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ABSTRACT
Many hazardous materials are manufactured for specific industrial
and agricultural applications. These materials often are applied for
beneficial uses, and are accidentally spilled, or released through waste
streams into the environment. This study documented the existence in
the environment of biological, chemical, and physical transformation
processes for hazardous materials. Studies determined that the slow
rate of transformation of these hazardous materials results in the
persistence and bioaccumulation of certain potentially harmful residues
in living systems. A scheme to minimize the release of unwanted
hazardous chemicals into the environment is described.
iv
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CONTENTS
Page
iv
v
1
2
. . . 5
5
'. ....... 8
Technology Alternatives 10
SUMMARY 12
REFERENCES . . 13
ABSTRACT
LIST OF FIGURES AND TABLES
INTRODUCTION
Biodegradation
Induced Formation of Bacterial Enzymes
Pesticide Metabolism
Photodegradation
Bioaccumulation
Number
Figure 1
Figure 2
Figure 3
FIGURES AND TABLES
Mechanism for Degradation of Pesticide
Containing Aromatic Structure
Scheme of Metabolic Transformation of DCPA
Scheme for Processing Hazardous Waste for
Recovery and/or Disposal
Table 1 Enzymatic Reaction in Pesticide Metabolism
Page
4
6
11
3
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DEGRADATION MECHANISMS: CONTROLLING
THE BIOACCUMULATION OF HAZARDOUS MATERIALS
INTRODUCTION
In recent years, the release of synthetic organic chemicals into
the environment has greatly increased. Although many of these materials
are decomposed naturally by chemical, physical, and biodegradative
processes, a surprisingly large number of the synthetic compounds (or
products formed from them) are destroyed at rates too slow to prevent
undesirable accumulations in the environment. Because of the threat to
public health, these compounds are attracting increasing attention. One
example of such compounds are the persistent insecticides that are
widely used in the temperate zone for food production and in the tropics
for the control of insects bearing human pathogens, and herbicides that
remain in the soil for years are important in the agricultural industry.
Persistence or nonbiodegradability is frequently a desirable
characteristic of a synthetic compound. Because of their low cost, low
acute toxicity to man, and long period of effect, certain persistent
insecticides remain the best means to control the insect vector of
malaria in developing countries. By suppressing weeds for one or
several seasons, persistent herbicides cost less for weed control in
agricultural areas and along highways and railroads. Similarly,
resistance of fabrics and packaging materials to biodeterioration
during the period of their use is a desirable feature.
On the other hand, resistance to natural degradation is quite often
an undesirable property. For example, components of industrial waste
effluents introduced into waterways, if not decomposed by the aquatic
microflora, can harm wildlife, reduce the quality of drinking water, and
result in the bioaccumulation of hazardous chemicals. Toxic accumulations
of persistent insecticides can enter living systems by means of: absorption
into earthworm tissues, then into birds feeding on the worms; soil
erosion into adjacent bodies of water, then into fish or other aquatic
life; and absorption into the roots of growing crops, then into the
livestock or humans who eat the crops. Phytotoxicity has been reported
in many areas where a persistent herbicide applied to a resistant crop
was not degraded by the time a succeeding but sensitive crop was sown in
the field, and farmers have sometimes incurred appreciable finanical
losses from residual toxicity of herbicides used in a crop rotation.1
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Resistance to degradation can also result in the presence of
DDT, aldrin, polychlorinated biphenyls, o-chloronitrobenzene, and
many other compounds in rivers and drinking water. However, the
possible hazard to man's health of a long-term exposure to low
concentrations of most nonbiodegradable pollutants is unknown.
Furthermore, in spite of rapid developments in toxicology, previ-
ously unrecognized or even untested effects on human health could
become evident several years from now as the result of the intro-
duction of a synthetic organic chemical into the environment. If
the chemical compound was susceptible to natural degradation,
cessation of human use would result in the disappearance of the
newly recognized toxicant from ecosystems. By contrast, if the
compound was nonbiodegradable, its harmful effects would continue
for months, years, or decades, because of the absence of an
effective means to rapidly eliminate the offending chemical from
natural ecosystems. Thus, the widespread dissemination of non-
biodegradable or persistent chemicals is an inherent risk, since
detection and control of their toxic effects is contingent and
unreliable.
The purpose of the report is to delineate the mechanisms that
transform hazardous materials into toxically active and inactive
compounds and to describe treatment a scheme that minimizes the
release of unwanted materials into the environment.
Biodegradation
Studies on pesticide metabolism in insects have provided
considerable information on the interactions between the toxic
chemicals and the mechanisms of species resistance. The pathways
of pesticide metabolism were determined primarily with in vivo
degradation, and metabolities were recovered mostly as secondary
water soluble products. A more recent study,2 has involved the
use of individual insect tissues, cellular preparation, or both in
an effort to characterize primary metabolites. Results clearly
established the important role of hydrolysis, oxidation, reduction,
dealkylatioji, desulfuration, and dehalogenation in the biotrans-
formation of organochlorine, organophosphorus, and carbamate
insecticides in insects. Some of the basic enzymatic reactions in
pesticide metabolism are shown in Table I.3 Mechanisms for the
metabolic transformation of pesticides containing aromatic structures
are given in Figure 1. In principle, all enzyme-catalyzed reactions
are thermodynamically reversible; in some instances, however, the
equilibrium is so far in one direction that it precludes both the
reverse reaction or the resynthesis of the parent compound. The
function of the appropriate enzyme is to catalyze whenever feasible,
the attainment of equilibrium in either direction.
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Type Reactions
1. Hydrolysis-condensation or replacement
RCO-NHR' +H,O £ RCOOH+R' NH2
RCO-NHR'+R"NH2 ^ RCO-NHR"+R'NH2
RCO-OR' +H2O ± RCOOH+R'OH
RCO-OR'+R"OH * RCO-OR"+R'OH
RCO-SR'+HjO * RCOOH+R'SH
RCO-SR'+R"H* RCO-R"+R'SH
R-PO3H2+H3O * RH+H3PO4
R_PO3H2-I-R'OH =* RH+R'O-POjH,
R-PO3H,+R'NH2 * RH+R'NH-P03H2
R-CH-OR'+H2O^ RH+HO-CH-OR'
R_CH-OR'+R"H # RH+R"-CH-OR'
2. Phosphorolysis-condensation
R-CH-OR'+H3P04 * RH+H203PO-CH-OR'
3. Cleavage or formation of C— C linkages
RCOOH ± RH+CO2
H H
HO-C-C-OH ^ RCH,OH+R'CHO
R R'
4. Hydration-dehydration and related processes
H H H
R2C-C-OH ^ R2C=C+H2O
R R
H H H
R2C-C-NH, ^ R2C=C+NH,
R R
5. Oxidation-reduction
# A+BH2
AH2+H2Oc, -*A+2H3O
2H2O2 -»2H2O+O2
•The type formula R— CH— OR' denotes a glycoside
Enzyme Group
Proteinases, peptidases,
and amidases
Esterases
Thiol esterases
Phosphatases and
transphosphorylases
Clycosidases*
Transglycosidases*
Phosphorylases*
Decarboxylases
Aldolases
Hydrates and related en-
zymes (elements of H2O
or NH3 may be replaced
by those of H3S)
Dehydrogenases
Oxidases
Peroxidases
and catalases
Table 1 Basic enzymatic reactions in pesticide metabolism.
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H
XC\
HC COOH
I
Oj HC. COOH
OH \c/
H
Catechol
c/s,c/s -Muconic acid
H
HOOC
0OH O ^
HOOC
Protocatechuic acid
OHC
^ OH
o-
H3C
HOOC
H
I^O COOH
HC«vc>°
H
Y-Car boxy methyl-
Aa -butenolide
H,O
/} -Carboxymuconic acid
Suecinyl-CoA
Succinic acid
f COOH
^OOH
B -Ketoadipyl-CoA
/~CoA
Succinyl-CoA + Acetyl-CoA
-Ketoadipic acid
Figure 1 Mechanisms for degradation of pesticide
containing aromatic structure.
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Induced Formation of Bacterial Enzymes. Many microorganisms are
able to "adapt" to the utilization of one of a variety of substances
added to cultural medium by forming an enzyme system that is not
evident when the organism is grown in the absence of the added
substance. This phenomenon is termed "enzyme induction," and the
substance (i.e., pesticide, etc.) that initiated the response is
the enzyme-inducing agent. For example, the enzyme B-galactosidose
appears in Escherichia coli when the organism is grown in the
presence of B-galactosides such as lactose (a substrate of the
enzyme) or methyl-B-D-thiogalactoside (which is not hydrolyzed by
the enzyme).1* Thus, an inducer need not be the substrate of the
enzyme whose formation it invokes; yet, it appears that the
inducer serves as a template (perhaps in stimulating messenger
RNA) which plays a role in the synthesis of intracellular enzymes.
The pesticides also participate in some manner that elicits the
response as an enzyme inducer.
Pesticide Metabolism. Pesticides that are transformed by biological
systems include parathion, methyl parathion, DDT, dieldrin, 2,4-D,
MCPA, silvex, fenac, dalapon, atriazine, and DCPA.5 Pesticides
are metabolized both by the target organisms at which they are
directed and by man and other nontarget species. The herbicide
3,4-dichloropropionanilide (DCPA) is an example of a compound
whose metabolism results in a hazardously persistent residue.6
Bartha and Promer determined that DCPA is metabolized by a
number of soil microorganisms; they suggested that the labile
aliphatic side chain of the molecule is oxidized in part to carbon
dioxide and that the aromatic moiety is liberated as a toxic
residue that depressed soil respiration. By using fractionation
procedures on soil samples containing DCPA, they identified two
decomposition products—the metabolites 3,4-dichloroaniline (DCA)
and 3,3,4,4-tetrachloroazobenze (TCAB). The scheme of metabolic
transformation of 3,4-dichloropropionanilide in soil is illustrated
in Figure 2.
Acylamidase of microbial origin in the soil catalyzes the
cleavage of the herbicide DCPA into DCA and propionic acid. The
propionic acid is utilized as a source of carbon and energy by
soil microorganisms. The condensation that produces TCAB from
DCA may be a direct oxidative condensation of two molecules of
DCA; or DCA may be first transformed in part to 3,4-dichloro-
nitrosobenzene, after which a spontaneous condensation occurs
between one molecule of the aniline compound and one molecule of
nitroso. Because of these condensation reactions, DCPA accumulates
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_
Cl-/ \-
NH- CO- CH2-CH3
3' ,4'— dichloropropionanilide
+HOOC-CH2-CH3
propionic acid
I
CCh+'HaO
3,4,—dichloroaniline
3,3',4, 4'—tetrachloro—azobenzene
I A'
Figure 2 Scheme of transformation of 3',4
dichloropropionanilide in soil.
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in the soil as TCAB, an ozo compound; in the Barth and Proroer study,6
46% of the DCPA was recovered as TCAB 30 days after application of the
herbicide. Further study on the metabolites from decomposition of
this compound and all other pesticides is greatly needed.
Foreign chemicals, when introduced into higher living organisms
such as man, undergo metabolic transformation. Transformations
of the parent molecules are enzymatically induced by naturally
occurring and synthetic substances. Williams7 divided the biotrans-
formation mechanisms of foreign chemicals into two major types:
the nonsynthetic reactions involving reduction and hydrolysis, and
the synthetic reactions involving biosynthesis of a product from
the chemical and from an endogenous metabolite. The biotransformation
reactions are especially important in insects, since most of the
widely used pesticides are not effectively toxic until they are
metabolized in the host. Metabolic conversion of a chemical frequently
results in the formation of products that are more toxic than the
original compounds.8
Microsomal drug enzymes in the liver cells protect humans and
animals from the effects of foreign chemicals by catalyzing a
variety of biotransformation reactions—including hydroxylation,
dealkylation, deamination, akyl side chain oxidation, hydrolysis,
and reduction. Moreover, the total quantity of microsomal enzymes
is increased significantly when insecticides such as chlordane,
DDT, hexachlorocyclohexane, dieldrin, aldrin, and heptochlor are
administered repeatedly to animals. Yet, the final role of
microsomal-metabolizing enzymes in humans and animals after
exposure to toxic chemicals remains virtually unknown. Because of
the uncertainty of the effects of these enzymes, technology should
be developed and implemented to safeguard public health from
unnecessary exposure to these enzymes-inducing materials.
Photodegradation
Maugh9 reported that DDT vapors can be converted into poly-
chlorinated biphenyl's (PBC's) by irradiation with ultraviolet
light of the same wavelengths present in sunlight. This conversion
is a natural mechanism that produces a transformation product as
toxic as or more toxic than the parent chemical. In this natural
degradation process, the absorption (facilitated by a photosensitizer)
of irradiated solar energy into an insecticide, pesticide, or.
herbicide chemical increases molecular energy. Persisting for a
relatively long period of time at this high energy level, these
activated molecules release their absorbed energy, thereby effecting
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the photolysis of the pesticides and of their residues. With free
access to air and under illumination from sunlight or ultraviolet
light, hydroxyl groups replace halogens in a number of pesticides
in aqueous solution. The irradiation in water of such herbicidal
compounds such as chlorobenzoic acids and ami ben (3-amino-2, S-
dichlorobenzoic acid) with light of a wavelength directly absorbed
by the molecules leads to replacement of chlorine by both hydrogen
and hydroxyl. Picloram (4-amino-3,5,6-trichloro-picolinic acid)
is degraded by light under a variety of conditions. Photolysis of
picloram takes place in aqueous solution and in the solid phase.
In a study by Plimmer,10 1 mg of picloram applied to the surface
of a petric dish and irradiated with ultraviolet light was degraded
60 percent after 48 hours and 90 percent after 1 week.
The compound 3,4-dichloroaniline (DCA), whose transformation
in the soils to tetrachloroazobenzene (TCAB) by microbial was
discussed earlier, is also transformaed by photolysis. With the
aid of the photosensitizer benzophenone, Plimmer and Kearny11
photolyzed DCA in benzene solution to TCAB; and, even though
preliminary, their results clearly determined that the photo-
products of DCA were chemically identical to TCAB. Plimmer and
Kearney also demonstrated that 3,4-DCA is photolyzed in ultra-
violet light with riboflavin as the photosensitizer.
The widely used S-triazine group of herbicides has not yet
been thoroughly studied photochemically. Many reviews on pesticides
describe their inactivation by ultraviolet energy and by infrared
irradiation. It has not been clearly resolved whether loss of
pesticidial potency is due to volatilization or photodecomposition.12
It is also assumed that microbial and photodegradation reactions
play a major role in reducing the presence of persistent toxic
residues in the environment.
Bioaccumulation
In 1969 Heyndrick and Maes13 compared the concentrations of
organic chlorinated pesticides in the lipid fraction of mother's
milk with the accumulation of these pesticides in baby fat.
Twenty samples of human milk were analyzed quantitatively for
pesticide residues. The results revealed that babies having human
milk as a sole food source are exposed to a higher dietary in-
secticide concentration that the general population.
Presented in the Journal of the American Medical Association,14
a discussion of organophosphorus pesticides emphasized their
mechanism(s) of toxic action in the human body. Under certain
8
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circumstances, these relatively nontoxic pesticides (chemically
very similar to nerve gas) can be converted in the body to extremely
deadly poisons. In insects, inhibition of acetylcholine esterase
results in the accumulation of a lethal concentration of acetylcholine.
The same inhibition of acetylcholine esterase takes place in mammals,
but here rapid metabolization of the toxic substance minimizes the
effect. As long as the insecticide is decomposed more rapidly
than acetycholine is formed, there is no danger to health.
Accumulation of chemicals in a living cell requires that
sufficient amounts of the chemicals approach the cell membrane and
that the cell membrane allows their entry into the cell. If
removed from the environment of the foreign chemical in time, the
organism or cell usually avoids the toxic effect of the chemical.
Elimination rates of chemicals from organisms depend upon the
nature of the chemical and the mechanism used to remove the chemical
from the organism.
The elimination rates of chlorinated hydrocarbons were determined
in a study in New Zealand.15 Heifers and lambs were dosed daily
for 16 weeks with a mixture of DDT and dieldrin and were then
maintained for 32 weeks without dosing. More dieldrin than DDT
accumulated in the fat of both animals, and lambs stored more
dieldrin than heifers. Dieldrin and DDT were present in both
animals 32 weeks after the final dose.
Heavy metals are also accumulated by living tissues. One of
the heavy metals, mercury, occurs in the compound phenyl mercury
acetate, a major agricultural chemical. In 1968 H. Tokutomi16
conducted a follow-up study on mercury poisoning cases resulting
from use of this compound. Extensive neurological disorders
persisted with little or no improvements 10 years after the initial
poisoning. Not surprisingly, Tokutomi reported there are, as one
would suspect, many cases of heavy metal poisoning of humans in
developing countries. For example, the Ministry of Labor in El
Salvador recorded 2028 cases of poisoning (including 30 fatalities)
of humans in 1972. In addition, this data showed that the
problem of the persistence of pesticides residues such as DDT and
dieldrin in grazing pastures, in cottonseed oil, and in corn fed
to cattle posed a severe threat to domestic health. Because of
the potentially harmful (though frequently unknown) effects of
accumulated agricultural chemicals, technology that prevents the
release of these chemicals into the ecosystem should be developed
and implemented.
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Technology Alternatives
To reduce the impact of toxic and hazardous materials (whether
in liquid, semi-liquid, or solid form) on the environment, several
techniques have been developed and new promising technologies are
continuously being developed. Though in the past these unwanted
waste materials have been disposed by the quickest, easiest, and
most economical means, a recent increase in the supply of agricultural
chemicals and (more importantly) an increase in concern for the
environment places new emphasis on the implementation of treatment
processes prior to disposal. An acceptable approach to concentrate,
process, and reintroduce (when applicable) hazardous materials to
the market is schematically illustrated in Figure 3.
The physical state, chemical concentration, and recovery
potential of the waste stream determines the most economically
feasible processing route. Some waste streams could offer limited
resource recovery potential, require little or no concentration,
and could be disposed of directly. Semi-liquids and liquids could
be recovered for reuse or disposed of directly. However, in some
cases, a concentration and/or a detoxification step is needed to
safely recover the hazardous materials from the waste stream.
The concentration process includes techniques employing
reverse osmosis, ion exchange, activated carbon adsorption, and
impoundment. The nature of the influent and the extent of concen-
tration required would determine the best concentration procedure.
Most of these processes have been developed, and recent advances17
make them attractive for implementation in the control of hazardous
waste.
The detoxification process is necessary to treat those materials
that no longer require the toxic element or compound. Techniques
that could be employed to detoxify the waste materials include
chemical oxidation/reduction, catalytic, and substitution/transformation
processes. A product assessment would be necessary to ensure that
the detoxification process has been completed and that nothing
harmful from the original hazardous waste stream remains in the
recovered products.
If implemented, any of these detoxification processes would
probably generate waste that requires disposal. Disposal methods
that could be used include ocean and deep well disposal, sanitary
landfills, encapsulation, and incineration. However, ocean and
deep well disposal are becoming unacceptable because of the
inability to control the possibly harmful effects of these waste
materials once they are placed in the sea or deep well environ-
10
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w
A
S
T
E
S
T
R
E
A
M
1
tration
cess
-*
i
Detoxification
Process
-^
*
Resource
Recovery
i
F
Product
Assessment
Market
Figure 3 Scheme for processing hazardous waste
for recovery and/or disposal
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ments; and incineration produces gases and residues that must be
controlled.
Specialized techniques for detoxification include wet oxidation
and chlorinolysis. A chemical analysis of the waste stream and
potential market of the end products usually dictates the feasibility
of one technique over another. End products could be disposed of
directly or resubmitted into the market recovery and reuse stream.
This resource recovery step in the above scheme could involve
additional concentration, identification of potential useful
products, and purification processes.
Before the return of material that once was toxic and hazardous
to the recovery and reuse stream, extensive short- and long-
term toxicological evaluation should be performed. Exceptions to
this are those products recovered for use as originally intended
(i.e., pesticides, organics, etc.).
SUMMARY
The mechanisms for degradation of hazardous materials in
nature are chemical, biological, and photodegradation processes.
Many hazardous materials are destroyed by these naturally occurring
processes but at rates too slow to prevent significant and unwanted
accumulation in living systems. Because natural transformation of
certain hazardous materials often leads to the synthesis of a
compound more toxic than the parent chemical compound, nonbio-
degradable structures can result in detectable and potentially
harmful bioaccumulation in living systems. Therefore, safe
technologies for resource recovery and waste disposal should be
developed and implemented to minimize the undesirable release of
hazardous materials into the environment.
12
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REFERENCES
1. Alexander, M. Nonbiodegradable and Other Recalcitrant
Molecules. Biotechnology and Bioengineering, Vol. XV,
p. 611-617 (1973).
2. Kuhr, R. Mechanisms of Insecticide Metabolism In Insects:
Tissue, Cellular, and Subcellular Studies. Presented at
167 American Chemical Society meeting, Los Angeles,
California (1974). Pesticide Chemistry Section, Abstract 21.
3. Fruton, J. S. General Biochemistry. Second Edition.
John Wiley & Son, Inc., New York, p. 216 (1958).
4. Monad, T., and M. Cohn. Advances in Enzymology. 13:67 (1952).
5. Atkins, P. The Pesticide Manufacturing Industry-Current
Disposal Practices. Report No. 1202FYE01/72, NTIS No.
PB-211 129. U.S. Environmental Protection Agency (1972).
6. Bartha, R., and D. Promer. Pesticide Transformation to
Analine and Azo Compounds in Soil. Science, 156:1617-18
(1967).
7. Williams, R. T. Detoxification Mechanisms. John Wiley and
Sons, Inc., New York (1959).
8. Schuster, L. Metabolism of Drugs and Toxic Substances.
Ann. Rev. Biochem. 33:571-596 (1964).
9. Maugh, T. H., Jr. DDT: An Unrecognized Source of Polychlorinated
Biphenyls. Research News. p. 578 (May 11, 1973).
10. Plimmer, J. R. Photolysis of Amiben Weed Sci. Soc. Amer. Abstr.
p. 76. Washington, D.C. (1967).
11. Plimmer, J. R., and P. C. Kearney. Division of Pesticide
Chemistry. 158th meeting, American Chemical Society,
New York (September 1969).
12. Ercegorvich, C. D. What Happens to the Triazines in Soil?
Ardsley. New York. p. 22 (1965).
13. Heyndrick, A. and R. Maes. Excretion of Chlorinated
Hydrocarbon Insecticdes in Mother's Milk. J. Pharm. Belg.
24:459-463 (Sept.-Oct. 1969).
13
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14. Pesticide Poisoning Remains a Major Problem. J. Am. Med.
Assoc. 217:1315-1319 (Sept. 6, 1971).
15. Insecticide Studies. Journal of Animal Research in the
New Zealand Department, p. 55-57. (1966).
16. Tokutomi, H. Symposium on Clinical Observations on Public
Nuisances and Agricultural Pesticide Poisoning. Organic
Mercury Poisoning. Nippon Naika Gakkai Zasshi, 57(10):
12126 (1968).
17. Landreth, R. E., and C. J. Rogers. Promising Technologies
for Treatment of Hazardous Wastes. Report No. EPA-670/2-
74-088. U.S. Environmental Protection Agency, Cincinnati,
Ohio, (1974).
18. Schuster, L. Metabolism of Drugs and Toxic Substances.
Ann. Rev. Biochem. 33:571-596 (1964).
14
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-670/2-75-005
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
DEGRADATION MECHANISMS: CONTROLLING THE
BIOACCUMULATION OF HAZARDOUS MATERIALS
5. REPORT DATE
January 1975; Issuing Date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Charles J. Rogers
Robert L. Landreth
9. PERFORMING ORGANIZATION NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
1DB311: ROAP 07ADZ; Task 10
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
SAME AS ABOVE
In-house
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Numerous toxic and hazardous compounds are being generated for commercial,
industrial and agricultural uses. Most of these materials are eventually
released into the environment. This study documented the existence of biological,
chemical and physical transformation processes of hazardous wastes in the
environment. It was determined that the rates of transformation of these
hazardous materials, when applied and/or discharged to the environment, are slow.
Case studies confirmed that persistency of certain hazardous materials results
in the bioaccumulation of residues in living systems. A lack of knowledge of
the fate and clinical manifestation of persistant residues in living systems
dictates the need for implementation of the described scheme of control technology.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COS AT I Field/Group
Pesticides, Hazardous materials,
Metabolism, Enzymes, Biodeterioration,
Photodegradation, Degradation, DDT,
Herbicides, Dieldrin, Accumulation,
Materials recovery, Toxicity
Bioaccumulation,
Control technology
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
21
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
15
. S. GOVERNMENT PRINTING OFFICE: 1975-657-590/5339 Region No. 5-11
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