Spectrophotometric Methodologies for Predicting and Studying

Chapter 18

Spectrophotometric Methodologies for Predicting and Studying Enhanced Degradation 1

2,3

1

Joseph P. Reed , Robert J. Kremer , and Armon J. Keaster

Downloaded by UNIV OF MICHIGAN ANN ARBOR on February 18, 2015 | http://pubs.acs.org Publication Date: May 3, 1990 | doi: 10.1021/bk-1990-0426.ch018

1

Department of Entomology, University of Missouri, Columbia, MO 65211 Department of Agronomy, University of Missouri, Columbia, MO 65211 Agricultural Research Service, U.S. Department of Agriculture, Columbia, MO 65211 2

3

Currently i t is difficult to assess the incidence of enhanced degradation of soil-applied pesticides at a specific location. Simple, reliable diagnostic tests are needed that can be used to evaluate potential enhanced degradation scenarios. Using standard soil extraction methods, spectrophotometry can provide simple, specific and sensitive detection of pesticides and their metabolites in soil. Such methodology will provide information useful in predicting potential enhanced degradation before pesticide application and implementing more reliable recommendations for controlling the target pest. Enhanced munity

degradation

because

persistence which

is

not

demonstrate

repeated soils

referred

as

the

are

same

edaphic and

manifests

itself

appear

pest

control

failures

not

to

soils

even

to

be

of

the

is

of

with

problem at paramount

i n N e b r a s k a d u r i n g 1983

and of

the

state

grower

L . ) ,

Missouri an

(2).

This a weed

pesticides.

poor

and

rate

or

enhanced

though

Soils following

'aggressive' degradation

both

soils

to

this

indicated 20% o f

failure

the

are

may

1984

A

was

a l l

area.

other

for

the

parts

to

be

was of

due

to

(Panicum

A 1984

survey

the

corn producers

used

that

herbicides

presumed

about

through

survey

concluded

than

use

level

shattercane

and almost

insecticides

degradation

carbamothioate

concerns

the

field

importance.

difference of

enhanced

upon p e s t i c i d e

Nebraska

control

endemic

Over

pesticide

herbicides

Central

regional

of

corn producers

outright

both

degradation

South

perceptions

miliaceum their

in

control.

'problem'

which

dependent

of

prevalent

pest

com-

their

characteristics.

incidence more

as

agricultural

rapidly that

degradation

displaying

conducted

enhanced

the so

satisfactory

importance

Perception

in

degraded

pesticide

referred

'non-problem'

extent

concern

are

for

soils

The patterns.

growing

increased

Likewise, to

a

adequate an

application

(1).

possess

is

some p e s t i c i d e s

had

30% r a t e d corn pest

of

performance

of

experienced

performance control

0097-6156/90/0426-0240$06.00/0 © 1990 American Chemical Society

In Enhanced Biodegradation of Pesticides in the Environment; Racke, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

as

of poor

18. REED ET AL. Q ) .

Surveys

of

major

efforts

that

undertaking enhanced GLC)

the

feasible

perceptions

yield

research

dubious several

using

laboratory.

and w o u l d be

further

of

and c o s t - e f f e c t i v e

rapid

for

pesticides

management This

a

diagnostic

of

the

of

paper

method.

method

degradation

enhanced briefly

for

in

their and

by

methods

suffices

costs

of

reagents

used.

allowing

recovery

for

for

of

the

(4).

in

of

of

or

some

the

on

the

for

this

sensitivity of

substance

is

candidate

for

are

This where

the

determining

(6,2).

absorption

is

advantages

of

this

of

spectra

of

potential a

of

is

field

the

for

are

are

optical holds

in

system

high.

The

much are

(5,6).

to

be

analyses. since is

a

emitted The

loss

not

of

a

is

good

quite

spectrophotometry, long

of

wavelength,

organic

infrared

spectra

identification

since

quantitation

readily

application

available to

field

metabolite

is

compounds.

and

pesticide

and

readily

absorbed by

of

and

the

substance

methodology

spectra

method

specific

a

technique

Infrared

on

technique

quite

It

a

Ultraviolet

use

light

the an

Different

depending

the

common.

structure

Collections has

on

identification

chemical

(4).

instruments

wavelength

The c h a r a c t e r i z a t i o n

presence

chemical

quantitative

many b i o c h e m i c a l

although

methodology

and

unaltered

containing

detection.

this

i n which

use,

between

sample

containing

standard

c a l i b r a t i o n checks,

in

of

Numerous h a n d b o o k s

of

in-field

useful

of

amounts

comparison of

available

for

later.

to

a

instruments

method

technique

difficult.

such

different

use

the

other

absorption

this

established.

compound

are under

with

laboratory

Relationships well

a

by

because volumetric

remains

solution

Commercial

aspects

frequent

on c h a r a c t e r i s t i c

powerful

as

applications

quantity

solution

and,depending

of

applicable

levels for

adequate

of

a

a versatile,

discussed

light

small

of

reducing often

the

instrumentation

specific

requires

excitation

is

spectrophotometry,

(fluoresce),

based

be

the

causes

technique

methods

technique

such

and w i l l

Fluorescence

soil-

enhanced

that

allows

by

and a

characteristic

the

on

future

advantageous

analyses

substance,

identification.

employed,

adaptability

of

attractive

HPLC.

substance

available

available

sample

p a r t i c u l a r substance

for

are

essentially

same

based

promise

the

transmitted

that

is

very

to

beyond

thereby

confirmatory

spectrophotometry

sample

of

application

spectrophotometry

and

A relatively

Also,

visible the

of

subject

methods

determination

spectrophotometric

of

basis

and p r e c i s i o n

spectrophotometer

known q u a n t i t y types

a

absorbed

unknown q u a n t i t y

nature

the

detection

would be

current

pesticides

i n c l u d i n g GLC and

The

difficulty

Methods

simplicity,

gravimetric

radiation

the

summarizes

detecting

often

techniques

field

(e.g.,

economically

degradation.

spectrophotometric

speed,

undergo

soil.

Spectrophotometric Analyses

the

are

major

to

always

However,

for

a

techniques

not

by

data.

metabolites

examines

It

suspected

are

complicated

performance

would be

analytical

method

their

It

pesticides

efficacy/field and

pesticide

Such endeavors

accurate

a

of

results.

standard

collecting applied


to

grower

degradation

in

241

Spectrophotometry Methods

is

of

are a

is (5,6). situations a

factor.


a

242

ENHANCED BIODEGRADATION O F PESTICIDES IN T H E ENVIRONMENT

Spectrophotometric

Applications

Certain

pesticides

c a n be

solvent

and be

exposed

to

vary

light

depending

record

of

spectrum


nm,

have

which

available

to

for

color

react

with

The c o l o r e d a

nm).

F o r example,

ethylcyanoacetate

to

specific can in

the

yield

a

be

the

light

a

Most range

of

200

to

for

have

been

reagent

pesticide

is

mole-

quantitatively spectrum

herbicides

complex

these

will

Thus,

absorption

methods

detected

triazine

of

an

an a p p r o p r i a t e

red-colored

detection

light

spectrophotometer

visible of

of

compound.

in

a

compound.

wavelength

moiety

then

the

into When

has

(400

been

herbicides

to

700

with

in

developed

soil

(9).

Immunoassays, of

analytical

procedures

animal-derived antibodies

have

been

soil

and water

developed

as

rapid

samples.

after

water

which

generally

and

a

reaction

spectrophotometric

binding

pesticide in

the

spectrophotometric

complex the

of

yields

f o r m a t i o n when

spectrophotometer

extracts

wavelength each

and water

absorption

structure

an u l t r a v i o l e t

Other

on

using

with

each

soil

spectrophotometry.

wavelengths,

molecular at

from

by

a b s o r p t i o n maxima

(8).

based

for

different

the

requires

developed

extracted

directly

characteristic

determination

cule .

of

on

absorbance

pesticides 400

analyzed

or

quantitative

derived

method

for

of

specific

of

(10),

pesticides

analyzed

on

a visualization

the

method,

The most

color

in

site

antibody-pesticide

product.

monitoring

the

molecule

detection

the

colored

on

target

c a n be

using

reaction

based

a

for

samples

extraction

involves

an e n z y m a t i c a l l y

methods

Field

solvent

to

complex

sensitive

reaction

is

spectrophotometry. Unfortunately, for

a l l

pesticides

methods

based

common s o i l

microbial mediate (11).

cell

Assays

product

also

for

appearance

using

accomplished when

readily

acted used

presumed

General

Assay:

to

pesticides. These soil

with

results enzymes

in

or

been

function of

After

critical

detect (11)

the

be

soil

Activity

clay

loam

that

assay,

soil-buffer

by

or

assays system

product

that

Spectrophotometric

directly

responsible

for

monitoring activity

pesticide

degradation

of

(13).

Assays

levels

of

levels

certain

of

T u (14)

examined

various

microbial

and ethoprop-amended

influenced

enzymatic

colored

incubated with

activity

devised

disappearance Enzymatic

Problem S o i l s .

increased

carbofuransuggest

in

soils

c a n be

a

Enhanced Degradation

to

conditions

a

with

able

pesticides

to

enzymes

that

the

yields

i n d i r e c t l y by

associated

with

a n d may b e

substrate

substrate

enzyme,

or

within

soil-applied

spectrophotometer. a

coupled

demonstrated

meeting

for

by measuring

developed

alternative

microorganisms

(12).

the

been

c a n be

has

spectrophotometrically. to

not

extracellularly

soil

pH) the

He o b s e r v e d

may b e

that It

degradation

adding

Urease

activity

activity

by

degradation

Spectrophotometric

urease

in

upon by

detected

c a n be

pesticide enzymes

the

determined

have

Therefore,

normally

function

in

temperature,

c a n be

c a n be

assays

which

enzymes

which, is

reactions

developed.

enzymes steps

systems

agriculture.

standard procedures

(activators, activity

c a n be

can

certain

following

in

on b i o l o g i c a l

spectrophotometry many

immunoassay

used

soils

specific

pesticides

urease

(Table

I).

indigenous

applied


to

18. REED ET AL. soil for

or by

their

specific

control

pests

efficacy

insecticides. control the


of

like

of

corn

control

p r o v i d e d good

soil

area

assay

activities

Table

in

a

I.

Urease

root

ratings

soil

in

history

(15).

as

that poor

soils

involved

In

to

verify

Continued assay

as

(Table in

contrast,

on ethoprop h i s t o r y

used

diagnostic

Activity

soil-applied

revealed

microorganisms

degradation.

specific

of

assess

a n d e t h o p r o p was

rootworm c o n t r o l

definite

to

by

studies,

insecticides been

use

spp.)

field

An assay

observations

on c a r b o f u r a n

of

these

coupled with

degradation.

field

carbofuran

might have

microorganisms

may r e s u l t

corn

recent

presence

ethoprop of

of

treatment

degradation of

enzyme

l i n k e d to

r o o t w o r m (Diabrotica

rootworm by

i n d i c a t i n g the

soil

that

corn

enhanced A

formed d u r i n g

c o u l d be

For instance,

untreated

II),

metabolites

enzymes

agricultural

243

Spectrophotometric Methods

the

efforts

based

soils.

involvement

on

in

this

enzymatic

pesticides.

as

Influenced Urease (100

by

Pesticide

Amendment

Activity'

ug NH

+ 4

/g

soil)

Pesticide Carbofuran

21**

Ethoprop

19**

Fonofos

15

Phorate

16

Control

17

'Determined "Denotes Adapted

Table

after

7 days

significant from

II.

incubation of

difference

10

(P-.05)

ug

from

a.i./g

soil.

control.

(14).

Rootworm C o n t r o l

in

Carbofuran Root

Insecticide

Carbofuran

and Ethoprop

History

Rating

History

Ethoprop

History

Fonofos

3.40

3, . 5 0

Phorate

4.00

3. . 6 5

Ethoprop

4.55

3. . 0 0

Carbofuran

4.75

2, . 6 3

Control

5.10

5, . 5 0

Adapted

from

General

Assav:

(13)

(15).

Enzvme A c t i v i t i e s

characterized cell-free

bacterial assaying

and fungal the

diesterase. activity, presence

of

of

several selected

of

the

in

an Enhanced

culture

isolates

activities

using

filtrates a

rhodanese,

E l e v a t e d enzyme of

Soils

levels, microbial

pesticides

of

Reed

Soil.

spectrophotometric phosphatase expressed isolates

as

et

al.

actinomycete, and

method

phospho-

specific

cultured in

indicated a potential

the

for


for

244

ENHANCED BIODEGRADATION O F PESTICIDES IN T H E ENVIRONMENT

biodégradation

of

Mueller

(16)

that

et

al.

these

actinomycetes

pathways

pesticides

and Gauger et and b a c t e r i a

through which

(Table al.

III).

(17)

possess

many p e s t i c i d e

a

Recent

agrees

work

with

diversity

substrates

our

of

can

of

findings

metabolic

be

biodegraded.

Table

III.

Enzyme A c t i v i t i e s


Exhibiting

of

M i c r o o r g a n i s m s From

Enhanced P e s t i c i d e

Specific (ug Isolate

Pesticide

Soils

Biodégradation Activity

product/mg protein/h

Rhodanese

Phosphatase

@ 25

C)

Phosphodiesterase

Bacteria :

Alcaligenes Pseudomonas Pseudomonas Pseudomonas

IS*

#3 C B , BU #6 CB, IS, AL (R) None

8. .0

a**

1, .8

a

1 2 , .6

a

9, .1

a

1, .8

a

5, .2

b

4 , .3

b

1, .8

a

12, .1

a

4 . .5

b

1, .8

a

11, .0

a

0 b

Actinomvcetes:

Nocardia sp. None S t r e p t o m y c e s #13 T B , A L , BU S t r e p t o m y c e s #25 A l l S t r e p t o m y c e s (R) None

12, .0

a

3 0 , .4

b

5. .5

a

1 1 , .6

a

4 1 , .2

a

5. .5

a

1 1 , .8

a

61, .0

a

0 b

1 2 , .7

a

30, .1

b

Fungi :

A s p e r g i l l u s s p . EP, C L F u s a r i u m #25 E P , BU F u s a r i u m #210 IS Pénicillium (R) None 'Pesticides

metabolized

BU=Butylate; "Means

EP=EPTC;

within

a do

Adapted

(13).

EPTC

and B u t y l a t e :

determinations shown

not

to

be

microbial

of

of

reaction

products

a

2 6 , .8

b

1 2 . ,1

a

1 8 , .8

b

0 b

1 2 , ,5

a

4 5 , .5

a

0 b

1 1 . .3

a

2 1 , .2

b

each

in

diacetate

Diacetate

hydrolysis

rapid,

(18).

including

enzymes class

(protease,

of

changes

in

diacetate hydrolytic Reed

the

to

degrade

sample

activity et

al.

nm.

This of

since Also,

must

(19)

measure

be

abiotic

carbamothioate

method

rather

than

an a s s o c i a t e d

lag in

the

for

ability in

for

of

of

a

specific by

subtle

pH

in

soil

assay.

diacetate soil

enhanced

nonseveral

fluorescein

phase

of

the

detected

somewhat

of

each

fluorescein

herbicides

is

been

hydrolytic

influenced

hydrolysis

potential

the

have

determining

activity

accounted

adapted the

for

w h i c h may b e

may b e

a

Spectrophotometric

responsible

overall

esterase)

Enzyme a c t i v i t y

may o c c u r .

qualitatively

490

lipase,

enzymes.

is

by

diacetate

methods

fluorescein,

indicative

is

Assay.

Essentially,

at

it

followed

(P

Spectrophotometric Methodologies for Predicting and Studying

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