Fruit Surface Residues of DDT and Parathion at Harvest - Advances in


Chapter DOI: 10.1021/ba-1950-0001.ch023. Advances in Chemistry , Vol ... PDF w/ Links | Hi-Res PDF · World Use of Economic Poisons Advances in Chemist...
0 downloads 0 Views 508KB Size


Fruit Surface Residues of DDT and Parathion at Harvest M. M. BARNES, G. E. CARMAN, W. H. EWART, and F. A. GUNTHER

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 5, 2018 | https://pubs.acs.org Publication Date: January 1, 1950 | doi: 10.1021/ba-1950-0001.ch023

University of California Citrus Experiment Station, Riverside, Calif.

Surface residues of DDT and parathion at various times during the season and at harvest were determined for apples, pears, peaches, oranges, and lemons. Low level surface residues of parathion on apples were not carried over into cider. Harvest residues on fresh fruit are distinguished from residues present in food at the time of consumption which are included under the designation ultimate residues.

W i t h reference to the surface deposits accruing from orchard application of insecticides, certain characteristics which enhance their value as implements i n the chemical control of many species of insects—physical persistency and chemical stability—may also be conducive to the contamination of the harvested fruits with potentially deleterious residues. Supplementary to the need for data on the acute and chronic toxicity of these i n secticides to man and domesticated animals is the requirement for information concerning the magnitudes of the deposits that are present on or in foodstuffs as harvest or ultimate residues following commercial usage. The widespread commercial use of D D T [ 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane] and the potentialities of the more recently developed parathion (0,0-diethyl 0-pnitrophenyl thiophosphate) have placed emphasis on such investigations concerning these compounds. The Food and D r u g Administration has not as yet held hearings concerning the establishment of formal tolerances for D D T or parathion on fresh produce or i n processed foods. F o r apples and pears, an informal tolerance for D D T of 7 p.p.m. has been announced (3). [These hearings were i n progress at the time of publication.]

Scope, Definitions, and Methods This investigation is a portion of a general experimental program being carried out b y the University of California Citrus Experiment Station on the fate of insecticide residues (2) and methods of removing them (5). The discussion presented herein involves tree fruits and is largely restricted to a consideration of "surface residues." This term has been defined (5) to refer to residues present above the cuticle (extrasurface residues) and to deposits that may be incorporated i n the cuticle (cuticular residues). The quantities reported as surface residues are those present i n the solvent following standardized extraction procedures and include both extrasurface and cuticular residues. Little is known as to what extent insecticide residues may be redistributed through the epidermal layer i n the process of solvent extraction or stripping. While most of the data presented are representative of harvest residues on fresh fruit, some consideration is also given to residues present i n processed food. It is considered 112

AGRICULTURAL CONTROL CHEMICALS Advances in Chemistry; American Chemical Society: Washington, DC, 1950.

113

BARNES et α/.—FRUIT SURFACE RESIDUES OF DDT AND PARATHION AT HARVEST

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 5, 2018 | https://pubs.acs.org Publication Date: January 1, 1950 | doi: 10.1021/ba-1950-0001.ch023

appropriate to refer to residues present i n food at the time of consumption as "ultimate residues" (5). D D T was determined b y the dehydrohalogenation method (4). Parathion analyses were made b y the magenta color reaction of Averell and Norris (1) as modified b y Gunther and B l i n n (6). Two compounds or degradation products thereof which may cause the development of interference colors i n the magenta color reaction may be encountered i n surface residues resulting from commercial spray or dust applications. The first of these, dicyclohexylamine dinitro-o-cyclohexylphenate, is i n widespread commercial use, whereas the second, a dinitrocaprylphenylcrotonate, is involved at present only i n experimental and semicommercial usage. Blank corrections were provided for all sets of analyses. Samples for estimates of surface residue parameters on apples and pears were taken from three trees selected for representative size and shape among those of the experimental orchard. E a c h of the three samples consisted of 30 fruits. Six fruits were taken from each of four tree quadrants composing three fourths of the tree height and six from the top one fourth of the tree. These samples were generally taken before and after the penulti­ mate and ultimate orchard applications and at harvest. Samples for analyses of cider were taken from juice expressed with a hydraulic cider press. Samples of fruit for pressing were selected at harvest from a series for which parallel analyses for surface and pulp residues were made. E a c h of the triplicated peach samples was constituted b y selecting three fruits from each of eight trees. Citrus varieties were sampled b y selecting one fruit from each quadrant of seven trees. Replicate samples were taken from other sets of seven trees. Sample routing and manipulation have been described (6, 7). Table I.

Surface Residues of DDT on Rome Beauty Apples at Harvest

Technical Compound , Lb./100 Gal.

No. of Applications

Interval, Days&

Fresh Weight, Entire Fruit, P.P.M.

1 0.5 0.5 0.5 0.5 1

3 4 4 5 6 6

75 50 50 40 40 60

1.0 1.5 0.3 2.0 3.8 5.2

0

As wettable powder containing 50% technical D D T . b Since final application.

a

Table II.

Surface Residues of DDT on Bartlett Pears at Harvest

Technical Compound", Lb./100 Gal.

No. of Applications

Interval, Days*>

Fresh Weight, Entire Fruit, P.P.M.

2 1 1 0.5 0.5 0.5 0.5

1 1 2 2 2 3 4

110 110 70 70 85 40 14

0.9 0.4 2.2 1.6 0.9 1.2 2.7

As wettable powder containing 50% technical D D T . b Since final application.

α

Results The amounts of surface deposits resulting from commercial and experimental applica­ tions of D D T and parathion were ascertained on apples, pears, peaches, oranges, and lemons. Applications were made with conventional high pressure spraying equipment, utilizing manually operated guns or semiautomatic booms, and with two types of air blast sprayers. Surface residues of D D T on apples resulting from experimental applications applied in schedules comparable to commercial usage ranged from less than 0.5 to 2.0 p.p.m. at harvest. Schedules of application involving higher spray concentrations and greater fre­ quency of application than are at present required i n commercial practice resulted i n most cases i n residues of less than 7 p.p.m. T y p i c a l harvest residues are presented i n Table I. AGRICULTURAL CONTROL CHEMICALS Advances in Chemistry; American Chemical Society: Washington, DC, 1950.

114

ADVANCES IN CHEMISTRY SERIES

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 5, 2018 | https://pubs.acs.org Publication Date: January 1, 1950 | doi: 10.1021/ba-1950-0001.ch023

On pears, experimental applications of D D T applied in commercial schedules resulted in surface residues ranging from less than 0.5 to approximately 3 p.p.m. T y p i c a l harvest residues are shown i n Table I I . Intervals between application and sampling of apples retaining weathered surface residues of parathion ranged between 21 and 70 days. A t harvest, these residues were 0.05 p.p.m. or less, following each of 13 varied schedules of application (Table I I I ) . (These values are derived from samples containing an optimum amount of parathion for analytical precision.) Low level surface residues on apples were not carried over as u l t i mate residues i n cider (Table III). This fact supports the contention that there is close association of the parathion deposits with the waxlike coating of the fruit.

Table III. Technical Compound , Ounces/100 Gal.

Surface Residues of Parathion on Apples

0

Variety

Application

Interval, Days&

Fresh Weight, Entire Fruit, P.P.M. Pretreat- Posttreatment ment

Interval, Daysb

Fresh Weight, Entire Fruit, P.P.M. Surface Cider

Conventional Sprayer Rome Beauty

1 2 4 2 4 1

Delicious

2 2 4

3rd 4th 3rd 4th 3rd 4th 1st 1st 2nd 3rd 2nd 3rd 3rd 4th 2nd 3rd

21 25 21 25 21 25 27 36 27 36 27 36 27 36

0.02 0.01 0.04 0.02 0.09 0.09

0.01 0.01 0.02 0.01 0.03 0.02 0.09 0.05

0.3 0.3 0.4 0.4 1.3 1.0 0.5 1.2 0.5 0.3 0.8 0.6 1.4 0.6 2.2 0.9

41

0.02

c

41

0.02

c

41 70 70

0.05 Trace Trace c

0

c

29

0.01 c

29

o.'oi c

29

0.02'

00*

29

0.'05

00<*

c

Speed Sprayer Delicious (400 gal./ acre) Delicious (200 gal./ acre) Delicious (100 gal./ acre)

2

1st

0.3

22

0.01

4 4

1st 1st

0.4 0.5

22 22

0.01 0.04

8

1st

0.2

22

0.01

As wettable powder supplied by American Cyanamid Co. containing 25% technical parathion. & Since previous treatment. Harvest. Values reported for cider are from duplicate analyses of juice expressed from entire fruits of same series bearing indicated surface residues at harvest. a

c

d

On pears (Table I V ) parathion residues resulting from ten varied schedules did not exceed 0.08 p.p.m. at harvest. (These values are derived from samples containing an optimum amount of parathion for analytical precision.) Intervals between the terminal application and harvest ranged from 7 to 33 days. Surface residues of parathion on peaches were 4- to 15-fold higher than for comparable schedules on apples or pears, possibly because of the higher initial deposits retained on the more retentive surfaces of these fruits. Surface residues of D D T on peaches were also higher than those which would be expected to result from comparable schedules on apples and pears. T y p i c a l residue values for peaches are shown i n Table V . As compared with the residues of D D T present within citrus peel (#), the relative significance of surface residues of D D T on citrus fruits is diminished by the fact that these are readily removed i n large proportion b y the usual packinghouse processing (5). On oranges, typical surface residues of D D T at harvest ranged from less than 0.5 to approximately 2.5 p.p.m. following single applications. Under conditions of multiple a p plications and shorter intervals between treatment and sampling, a higher range of surface residues was found. Equivalent or larger amounts were generally present within the peel (#). Representative surface residues are presented i n Tables V I and V I I . AGRICULTURAL CONTROL CHEMICALS Advances in Chemistry; American Chemical Society: Washington, DC, 1950.

115

BARNES et α/.—FRUIT SURFACE RESIDUES OF DDT AND PARATHION AT HARVEST

Table IV. Technical Compound", Ounces/100 Gal.

Surface Residues of Parathion on Bartlett Pears

Application

Interval, Days 6

2nd 3rd 4th 3rd 4th 3rd 4th

28 27 21 27 21 27 21

Fresh Weight, Entire Fruit, P . P . M . PretreatPosttreatment ment

Interval, Days &

Fresh Weight, Entire Fruit, P.P.M.

7

0.08

Conventional Sprayer, Single Gun 2 2 4

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 5, 2018 | https://pubs.acs.org Publication Date: January 1, 1950 | doi: 10.1021/ba-1950-0001.ch023

8

0.01 0.01 0.03 0.02 0.04 0.03 0.08

0.3 0.5 0.7 0.8 1.1 2.6 2.1

c

33

o.

33

0.02

c

33

0.04

c

7

0.06

c

28

0.02

c

0.2 0.3

22

Trace

0.1 0.2 0.3

25 25 25

0.00 Trace Trace

oi

c

Conventional Sprayer, Broom Guns 2

2nd

2

4th

23

0.01

0.3

Conventional Sprayer, Fixed Nozzle Vertical Boom 22

0.01

0.2

Spray Duster (Master Fan Type) 8 gal./acre)

1st 2nd

27

0.03 Speed Sprayer

1 2 4

1st 1st 1st

As wettable powder containing 25% technical parathion. 6 Since previous treatment. Harvest.

a

c

Table V.

Attenuation of Posttreatment Surface Residues of Parathion and DDT on Lucas Beauty Peaches Technical Compound, Ounces/100 Gal.

Parathion Parathion DDT

Interval, Days 7 14 Fresh Weight, Entire Fruit, P . P . M .

4 8 8

0

C

4.5 10.9 16.1

30 0.2&

1.0 1.8 4.4

1.5 3.7 7.6

0.6b 2.7b

° As wettable powder containing 25% technical parathion. b Harvest. As wettable powder containing 50% D D T . c

Table VI.

Attenuation of Posttreatment Surface Residues of DDT on Citrus Following Single Applications

Type Formulation

Technical Compound, Lb./100 Gal.

Wettable powder Kerosene solution Kerosene solution Light medium oil solution

2.0 2.0 1.0 1.2

Interval, Days" 141 2 141 2 Fresh Weight, Entire Fruit, P . P . M . Valencias Lemons Navels 17.1 8.9 2.8 2.2

2.16 2.3b

1.56 0.26

16.2 4.9 3.0 2.1

23.9 14.0 3.2 2.7

1.7 2.3 0.2 1.3

Application, 10/1/45. b Harvest.

a

Table VII.

Surface Residues of DDT on Valencia Oranges at Harvest Following Sequence Applications

5/9/46 S S S

Applications 6/7/46

v 's 2

S

0

8/9/46

Interval, Days 6

Fresh Weight, Entire Fruit, P.P.M.

117 88 88 25

2.3 5.8 8.4 6.3

Kerosene-Velsicol AR-60 (95-5) 3 gallons, technical D D T 2 lb., and blood albumin spreader 0.25 lb. per 100 gallons of water applied as full coverage spray (S) or outside coverage spray O A S). 6 Since application. a

On lemons, surface residues at harvest ranged from 2 to 3 p.p.m. (Table V I I I ) , some­ what larger amounts being generally present within the peel {2). AGRICULTURAL CONTROL CHEMICALS Advances in Chemistry; American Chemical Society: Washington, DC, 1950.

116

ADVANCES IN CHEMISTRY SERIES

Table VIII. Attenuation of Surface Residues of DDT on Eureka Lemons Technical Compound , Lb./lOO Gal.

1

0

Interval, Days 23 35 44 Fresh Weight, Entire Fruit, P . P . M .

84

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on March 5, 2018 | https://pubs.acs.org Publication Date: January 1, 1950 | doi: 10.1021/ba-1950-0001.ch023

2 15.8 6.4 ... 2.9b 2 ... 7.8 ... 2.36 ° Kerosene-Velsicol AR-60 (95-5) 3 gallons, technical D D T 2 lb., and blood albumin spreader 0.25 lb. per 100 gallons of water. 6 Harvest.

Studies on oranges (Table I X ) have shown that surface residues of parathion are also of relatively low magnitude i n comparison with the quantities found within the peel (#). Surface residues on these fruits decreased rapidly (5), reaching values of 0.01 p.p.m. or less at harvest following a single application at required dosages. Table IX.

Surface Residues of Parathion on Navel Oranges at Harvest

Technical Compound , Lb./lOO Gal. 1 1.25 1.5 1 0

α

No. of Applications 1 1 1 2

Interval, Days ^ , ^ . „ . „ . 0 Fresh Weight, Entire Fruit, P . P . M . 0.01 0.02 0.09 0 20 1 1

U x

A

A

1 4

As wettable powder containing 25% parathion. First application 9/15/47, second application 10/15/47.

Acknowledgment The authors are indebted to the American Cyana'mid Company for supplies of the wettable powder of parathion used i n these trials.

Literature Cited (1) Averell, P. R., and Norris, M . V., Anal. Chem., 20, 753 (1948). (2) Carman, G . E., Ewart, W. H . , Barnes, M . M . , and Gunther, F . Α., ADVANCES IN CHEMISTRY SERIES, 1, 128 (1950). (3) Food and Drug Administration, Federal Security Agency, Trade Correspondence Letter 3-A (Nov. 5, 1945). (4) Gunther, F . Α., Hilgardia, 18, 297 (1948). (5) Gunther, F . Α., Barnes, M . M . , and Carman, G . E., ADVANCES IN CHEMISTRY SERIES, 1, 137 (1950). (6) Gunther, F . Α., and Blinn, R. C., Ibid., 1, 72 (1950). (7) Gunther, F . Α., and Miller,, M . E., Ibid., 1, 88 (1950). P A P E R 624, University of California Citrus Experiment Station, Riverside, Calif.

AGRICULTURAL CONTROL CHEMICALS Advances in Chemistry; American Chemical Society: Washington, DC, 1950.