Document 44v5nYQx0yVqX3qNGorKE0Mma

I f 1 TRANSLOCATION OF THE POLYCHLORINATED BIPHENYL AROCLOR 1254 FROM SOIL INTO CARROTS UNDER FIELD CONDITIONS Y. IWATA and F. A. GUNTHER Citrus Research Center and Agricultural Experiment Station ; Department of Entomology, University of California Riverside, California 92502 The extent and selectivity of transfer of the components of the polychlorinated . biphenyl (PCB) Aroclor 1254 from a sandy loam soil into carrots under field conditions were studied. Five of the gas chromatographic peaks of this PCB, designated 1, 4, 5, 8, and 10 with increasing retention time, were quantitated. After 23 months the concentration of peak 10 in soil remained unchanged, but peak 1 decreased by 34 3%. Lesser chlorinated peak 1 was translocated from soil into carrots five to eight times more than highly chlorinated peak 10. The residues (in ppm) of peaks 1 and 10 in carrot root were 30 to 50% and 3 to 4%, respectively, of that of the soil: The degree of translocation for PCBs was of the same order of magnitude as for the persistent organochlorine insecticides. Carrot foliage contained 1 to 6% as much of the PCB residues (in ppm) as the soil. Since peak 1 was present in about 2.5 times greater amount than peak 10 in foliage, whereas it was present in about five to nine times greater amount in roots, direct foliar contamination by soil dust is suggested. Polychlorinated biphenyls (PCBs) are worldwide environmental contaminants, resistant to degradation, subject to biological magnification, and have been reported in human tissues and milk. Their properties, production and uses, transport and transformation in the environment, environmental distribution, toxic impurities, biological effects, and analytical methodology have been reviewed (Gustafson 1970, Edwards 1971, Reynolds 1971, Fishbein 1972, Peakall 1972, Selikoff 1972). The toxicity, metabolic fate, and environmental chemistry of the PCBs are the subject of much current study. Evidence for the ubiquitous distribution of PCBs in water, in soils, and in fish, birds, and mammals continues to accumulate. In Scotland sewage sludge samples have been shown to contain 1 to 185 ppm of PCBs on a dry weight basis (Holden 1970). In inland areas the sludge may be disposed of by spreading over the land surface, and thus offer a route for PCBs into terrestrial food chains. The biological stability of PCBs is high in relation to DDT, When DDT and PCBs are added to activated sludge and digested anaerobically, DDT is metabolized, mainly to DDT but also to more polar substances, within a few days, while PCBs remain intact after a 40-day period (Jensen 1972). The use of PCBs as a pesticide extender or synergist also offers a route for PCBs into the terrestrial environment, especially agricultural lands. Nisbet and Sarofim (1972) estimate that the input into soils via the use of PCBs as pesticide extenders is less than ten Archives of Environmental Contamination and Toxicology Vol. 4, 44-59 (1976) 1976 by Springer-Verlag New York Inc. 44 ' ' DSW 379192 STLCOPCB4100070 RINATED IL INTO IONS me polychlorinated -aer field conditions aesignated 1,4,5, '.er 23 months the . reased by 34 37c. rive to eight times aeaks I and 10 in . soil: The degree of for the persistent much of the PCB : 2.5 times greater five to nine times . is suggested. ml contaminants, ave been reported es, transport and toxic impurities, Gustafson 1970, elikoff 1972). me PCBs are the _tion of PCBs in accumulate. In t>5 ppm of PCBs . y be disposed of a-s into terrestrial DT. When DDT ically, DDT is thin a few days, use of PCBs as a o the terrestrial "2) estimate that less than ten Translocation of PCBs into Carrots 45 tons/year. In Japan the ingesting of rice oil contaminated with PCBs has resulted in the widespread occurrence of a serious new disease, Kanemi Yusho (Nishikawa et al.J912). As the consequences of ingesting and accumulating PCBs by human beings, though known, are not fully understood, and as little is known of the behavior of PCBs in the terrestial environment, a study to obtain data on the translocation of-PCBs from the environment, specifically soil, into food crops was initiated. As carrots are known to absorb or "scavenge" organochlorine pesticide residues from soil (Lichtenstein 1959, Schupan 1960, Fox et al. 1964, Lichtenstein I and Schulz 1965, Lichtenstein et al. 1965,Harris and Sans 1967), the extent and J selectivity of translocation of PCBs from soil into carrots were studied. Prej liminary results have been reported elsewhere (Iwata et al. 1974); the data from this I - earlier publication are included in the tables and, where necessary, in the discussion | in this report to make it more meaningful. ( . I .. . - ... i ._ Experimental The following procedure was used to treat field plots to a six-in. depth with 100 . ppm of Aroclor 1254. A solution was prepared by adding one qt of ethanol and one . pt of Triton X-100 to 12.6 lb of Monsanto Company's Aroclor 1254 dissolved in 1 0.5 gal of toluene, and then adding sufficient water to make six gal. Using a vegetable crop sprayer with a 12-ft boom suspended 18 in. above ground, 5.5 gal of the solution was applied on December 20, 1971 on four replicate 10 x 50 ft plots ; separated from each other by untreated buffer strips. The field was rototilled to a | six-in. depth on the same day. The plots were seeded on July 31, 1972 and on July j 27, 1973 with Goldinhart, Burpee Seed Company's special strain of Red Cored Chantenay, which at maturity has a root length of 5.5 in. and diameter at the shoulders of 2.25 in. Soil. The soil was a sandy loam containing 56.6% sand, 31.2% silt, and 12.2% clay. The saturation percentage, organic matter content, and pH were 20.2%, 0.6%, and 7.6, respectively. The soil sampling procedure has been described (Iwata et al. 1974). * For extraction, two subsamples, each representing 20 g of oven-dry soil, were each placed without drying (Saha et al. 1969) in a four-oz screw-capped bottle and one ml of water was added if samples contained less than 1.5 g of water. After adding 40 ml of an acetone-hexane mixture (1:1 v/v), the bottle, closed with aluminum foil and a Teflon-lined screw-cap, was shaken for one hr on a mechanical shaker. The shaking was repeated twice, using 40 ml of fresh solvent each time, with a ten-min shaking period. Each time the supernatant solvent mixture was decanted onto a single column of 25 g of anhydrous Na,S04 and all eluates were collected in a single flask. The soil, bottle, and NaoSOj column were finally rinsed with 40 ml of hexane. The combined solvent mixture was removed using a rotary vacuum evaporator, and the residue was transferred with hexane to a 100-ml volumetric flask and made to volume. DSW 379193 STLCOPCB4100071 46 Y. Iwata and F. A. Gunther Several samples were checked for adequate extraction by adding two ml of water to the extracted soil and repeating the entire extraction procedure; only 1 to 27c additional PCB was recovered. A 5-ml aliquot of each soil extract was cleaned up using a glass column (30 x 2.5 cm od) packed to a height of ten cm (about 19 g) of Florisil (60/100 mesh, stored at 130C until used) and topped with a one-cm layer of Na-,SOA (Reynolds 1969). The column was prewashed with 50 ml of hexane (discarded). The soil extract was then added, and the column was eluted with 200 ml of hexane. The eluate was concentrated, and the volume was adjusted to 25 ml. Several columns were checked for adequate PCB elution by separately collecting 100 ml of additional eluate; only 1 to 2% additional PCB was recovered. Carrots. Four treated and four control samples were selected at random from each plot on October 11 and again on November 20, 1972. Four treated samples and one control sample were taken on November 12, 1973. These were scrubbed with warm water to remove adhering soil particles and then chopped with a food chopper. The October 1972, November 1972, and November 1973 samples, respectively, consisted of an average of 68 carrots with a mean weight of 21 g each, 28 carrots with a mean weight of 62 g each, and 26 carrots with a mean weight of 64 g each. Duplicate samples were extracted and hexane extracts were prepared using the procedures described below. October 1972 and November 1973 samples were processed using only procedure (a), while November 1972 samples were processed using all three procedures. (a) Blend 100 g at high speed for two min with 200 ml of acetonitrile and ten g of Celite and filter by suction. Measure the filtrate and partition into 100 ml of hexane by flooding with 600 ml of water (Mills et at. 1963). Re-extract the aqueous phase with 100 ml of hexane, combine the hexane extracts, wash twice with 100-ml portions of water, dry with Na2S04, and concentrate. (b) Blend the pulp obtained from procedure (a) at high speed for five min with 350 ml of acetonitrile-water (65 + 35) and filter by suction (Bertuzzi et at. 1967). Measure the filtrate and partition into 100 ml of hexane by flooding the extract with 500 ml of water. Re-extract the aqueous phase with 100 ml of hexane, combine the hexane extracts, wash twice with 100-ml portions of water, dry with Na2S04, and concentrate. (c) Blend 20 g at high speed for three min with 200 ml of 2-propanol-hexane (1+2). Decant the supernatant liquid and repeat the blending operation on the residue. Partition the combined filtrates into 100 ml of additional hexane by flood ing with 500 ml of water. Re-extract the aqueous phase with 500 ml of hexane, combine the hexane extracts, wash twice with 100-ml portions of water, and dry with Na2SOv Extract the pulp for 12 hr in a Soxhlct apparatus with CHC1 :i-CH.,OH ( 1 + I) (Mumma et at. 1966, Wheeler el at. 1967). Remove the solvent with a rotary STLCOPCB4100072 ng two ml of water ure; only 1 to 2% lass column (30 x isil (60/100 mesh, Sa2S04 (Reynolds scarded). The soil ml of hexane. The i. Several columns 00 ml of additional ed at random from treated samples and vere scrubbed with ith a food chopper, tples, respectively, g each, 28 carrots :ight of 64 g each. prepared using the 973 samples were ies were processed onitrile and ten g of j 100 ml of hexane . the aqueous phase wice with 100-ml for five min with :uzzi et al. 1967). ng the extract with exane, combine the with Na2S04, and 2-propanol-hexane - operation on the .1 hexane by flood:00 ml of hexane, of water, and dry _;h CHCI3-CH3OH tvent with a rotary j Translocation of PCBs into Carrots 47 vacuum evaporator, transfer the residue into a separatory funnel using 100 ml of methanol and 100 ml of hexane, and flood with 600 ml of water. Re-extract the i aqueous phase with 100 ml of hexane, combine the hexane extracts, and dry with j Na2S04. Combine the hexane extracts from the blending and Soxhlet extractions and i concentrate. ! I The cleanup procedure for the soil extracts was used for the carrot extracts. To j limit the amount of PCBs and co-extractives placed on the column, 2, 50. and 10% j aliquots of the extracts obtained by procedures (a), (b), and (c), respectively, were { used. After eluting the column with 200 ml of hexane, several columns were further ! eluted with 100 ml of hexane to confirm that PCBs were completely removed from the column. Foliage. 1972 Crop. Foliage from the carrots sampled on October 11, 1972 (four treated and one control) was removed, rinsed several times with water, and chopped. | Duplicate 100-g subsamples were extracted with acetonitrile using procedure (a) and i a 10% (10 ml) aliquot of the final hexane extract was cleaned up on a Florisil \ column as described for soil. | 1973 Crop. Samples of 50 carrots each were taken from treated plots C and D and f from a control area on September 30, 1973. Average weights for the root and | foliage, cut one cm above the root, were 2.9 and 6.1 g, respectively. Each sample \ was rinsed several times with water and dried, and the foliage was removed one cm | above the root and chopped. Duplicate 20-g sub-samples were each exhaustively l extracted using procedure (c) modified by dissolving the extractives obtained after I removing the CHCI3-CH3OH from the Soxhlet extraction in the filtrate from the ( hexane-2-propanol blending extraction. Foliage samples, cut one cm above the root, | were also obtained from the mature carrots sampled on November 12, 1973 from treated plots C and D and an untreated area. , Procedural recovery. Duplicate 100-g root samples were extracted using proce* dures (a) and (b); the extracts were fortified with 1000 /xg of Aroclor 1254 in ten ml of hexane or 50 p,g of Aroclor 1254 in five ml of hexane. After removing the hexane with a gentle stream of air to transfer the PCB into the acetonitrile phase, the extracts were partitioned with hexane, and an aliquot was cleaned up. Recovery data i are in Table I. i Duplicate 20-g root samples were extracted using procedure (c). The j 2-propanol-hexane and the CHCI3-CH3OH extracts were, separately fortified with ; 200 /xg of Aroclor 1254 in two ml of hexane. The extracts from the blending and the j Soxhlet operations were cleaned up and analyzed separately. Recovery data are in j ..... Table 1. i Duplicate 100-g 1972 foliage samples were extracted using procedure (a) and ] were fortified with 100 /xg of Aroclor 1254 in ten ml of hexane. Duplicate 1973 : foliage samples were fortified by adding 20 /xg'of Aroclor 1254 in 20 ml of hexane 1 DSW 379195 STLCOPCB4100073 48 Y. Iwata and F. A. Gunther to the Soxhlet extract. The recovery data (Table I) show that Aroclor 1254, once -3 extracted from the substrate, can be almost quantitatively partitioned into hexane and recovered from the Florisil column. Gas chromatography. The 1972 samples were analyzed as described by Iwata et al. (1974). A 1.7 m X 2 mm id column packed with 3% SE-30 on 80/100 Gas Chrom Q at 163C was used for additional studies. The 1973 root samples were analyzed using a Varian Aerograph 1700 gas chromatograph equipped with a 63Ni electron-capture detector. A 1.7 m x 2 mm id mixed column was used with a 30 ml/min nitrogen carrier gas flow rate and inlet, column, and detector temperatures of 240, 185, and 260C, respectively.The 1973 soil and foliage samples were analyzed using a Tracor MT-220 gas chromatograph equipped with a 63Ni electron-capture detector. A 1.8 m x 4 mm id mixed column was used with an 80 ml/min nitrogen carrier gas flow rate and inlet, column, and detector temperatures of 230, 200, and 265C, respectively. Quantitation of the peaks has been described (Iwata et al. 1974). The peaks quantitated (see Figure 1) were 1, 4, 5, 8, and 10. Peaks 2, 3, 6, and 7 were not used as the individual peaks were not well resolved and peak 9 was not used as its behavior was similar to peaks 8 and 10. The meaning of the "ppm" values resulting from these quantitations were discussed by Iwata et al. (1974). - \ PCBs in soil and foliage samples were quantitated by direct comparison to Aroclor 1254 standards. PCBs in root samples were measured by first quantitating Table I. Recovery of Aroclor 1254 from fortified carrot extracts. Substrate Extract Fortifi cation (ppm)c Recovery (%)d for gas chromatographic peak 1 4 5 8 10 Root 1972 Root 1973 Root 1972 Root 1972 Root 1972 Foliage 1972 Foliage Sept. 1973 Foliage Nov. 1973 ch3cn ch3cn CH3CN-H20a 2-propanol-hexane CHCl3-CH3OHb CH3CN Exhaustive Exhaustive 10 10 0.5 10 10 . 1 I 1 97 100 93 100 97 96 102 98 109 100 92 100 96 100 96 100 104 97 104 104 93 100 97 100 100 100 105 100 100 100 89 89 85 103 94 89 76 89 107 98 "Prepared from extraction of pulp obtained after CH:lCN extraction. bPrepared from Soxhlet extraction of pulp obtained after 2-propanol-hexanc extraction. ''Based on original fresh weight of substrate. dMcan of duplicate samples. Correction for background applied to foliage extracts. DSW 379196 STLCOPCB4100074 oclor 1254, once oned into hexane ccribed by Iwata et 30 on 80/100 Gas -rrograph 1700 gas . 1.7 m x 2 mm id low rate and inlet, oectively.The 1973 gas chromatograph m id mixed column inlet, column, and 1974). The peaks . 6, and 7 were not was not used as its '>m" values resulting 4). :rect comparison to by first quantitating at extracts. -very (<7c)d for gas imatographic peak 4 5 8 10 00 93 100 97 02 98 109 100 00 96 100 96 04 97 104 104 00 97 100 100 ,05 100 100 100 89 85 103 94 76 89 107 98 -hexane extraction, oliage extracts. j t : | ; , ' j ! I Translocation of PCBs into Carrots 49 one sample of root extract using an Aroclor 1254 standard and then using the sample as a secondary standard for the other root samples. No correction for background, as determined from control samples, was necessary for soil and root samples. The 1972 fortified foliage samples and all 1973 foliage samples were corrected for background, as determined from control samples (apparent PCB contamination) which may have been contaminated through the use of common glassware, such as the blender jars. Results and discussion Quantitation of the PCB residues in soil using each of five selected gas chromatographic peaks (see Figure 1) gave the results in Table II. If the Aroclor Fig. 1. Electron-capture gas chromatogram of extractives from 0.02 mg of soil (treated on December 20, 1971), 0.16 mg of mature carrot root, and 0.64 mg of foliage which were sampled on November 12, 1973. OSNN^9197 v STLCOPCB4100075 50 Y. lwata and F. A. Gunther 1254 recovered from the soil was unchanged in composition, the the ppm value for a sample would be independent of the quantitating gas chromatographic peak. One month after soil application the PCB residue as quantitated by each of five chromatographic peaks was essentially the same. However, the residue as quanti tated by peak 10 was 82 ppm greater than by peak 1, indicating that a slight alteration in the relative amounts of PCB isomers had occurred. This difference increased to 122, 204, 202, and 254 ppm after 7.5, 10, 11, and 23 months, respectively. The lesser chlorinated biphenyls, represented by peak 1, disappeared from the soil faster than the more highly chlorinated biphenyls. This effect is less evident between peaks 10 and 4. The ppm difference between them is 3 2, 7 1, 111, 132, and 11 2 after 1, 7.5, 10, 11, and 23 months, respectively. The more rapid rate of loss of the lesser chlorinated biphenyls from laboratory soils was reported by lwata et al. (1973). Although the relative changes in composition were demonstrated, the PCB re sidue represented by peak 10 did not appear to diminish with time. Residue varia tions of peak 10 determined for a given plot are attributed to irregularities resulting from uneven application and subsequent incomplete mixing of the treated surface Table II. Aroclor 1254 residues in field-treated soil. Plot Date sampled3 Residue (ppm)b for gas chromatographic peak 1 4 5 8 10 A Jan. 18, 1972 Aug. 15 Oct. 11 Nov. 22 Nov. 12, 1973 B Jan. 18, 1972 Aug. 15 Oct. 11 Nov. 22 Nov. 12, 1973 C Jan. 18, 1972 July 26 Oct. 11 Nov. 22 Nov. 12, 1973 D Jan. 18, 1972 July 26 Oct. 11 Nov. 22 Nov. 12, 1973 79 83 84 85 85 79 86 88 91 94 75 79 82 92 91 67 73 75 85 89 54 68 70 79 78 53 55 56 57 59 59 62 64 67 69 39 49 50 60 61 44 52 53 60 63 32 39 41 52 51 97 103 104 104 104 74 80 82 84 85 76 89 89 101 too 74 82 85 91 93 58 74 75 89 87 83 89 88 94 94 58 63 65 67 69 66 74 77 85 84 61 70 73 80 82 56 73 74 82 83 "Soil treated on Dec. 20, 1971. "Expressed as ppm equivalent of Aroclor 1254 unaltered in composition. Dry soil. Average of duplicate samples. dS\N37949S STLCOPCB4100076 ihe ppm value for a graphic peak. One by each of five residue as quanti tating that a slight _d. This difference i 1, and 23 months, eak 1, disappeared This effect is less era is 32, 1 I, respectively. The uboratory soils was ated, the PCB reae. Residue variaaularities resulting ae treated surface oil. ;ic peak 8 10 5 85 1 94 91 5 89 -j 78 59 69 i 61 63 51 - 104 85 100 93 87 94 69 84 82 83 n. Dry soil. Translocation of PCBs into Carrots 51 soil into the lower layers (Taylor et al. 1971). If the soil concentration of peak 10 was unchanged over the 23-month period studied, then the concentration of peak 1 had decreased 343% over the same period. Root-absorbed residues of dieldrin and DDT in carrots have been completely removed by the acetonitrile blending procedure (FDA Pesticide Analytical Manual) but, as the effectiveness of this procedure was unknown for PCBs, the pulp remain ing after removal of the acetonitrile extract from the November 1972 root samples was re-extracted with an acetonitrile-water mixture. Subsamples were also exhaus tively extracted. The.results (Table III) show that the residue level in the acetonitrile extract was 88 7% of that in the exhaustive extract. If correction is made for PCBs in the solvent unrecovered from the pulp, the residue by the acetonitrile extraction is 98 8% of that from the exhaustive extract. The theoretical extract volume is 283 ml [200 ml acetonitrile + 88 ml of water from 100 g carrots -5 ml correction for volume contraction (FDA Pesticide Analytical Manual)]. The actual volumes recovered were 2389, 2543, and 2542 ml for the October 1972, November 1972, and November 1973 samples, respectively. Re-extraction of the pulp obtained from the acetonitrile extraction with 350 ml of an acetonitrile-water mixture gave an additional 71 ppm of PCB residues. The combined residue found in the acetonitrile (uncorrected) and acetonitrile-water ex tracts is 958% of that obtained from the exhaustive extract. All acetonitrile extracts, after dilution with water, were partitioned twice, each time with 100 ml of hexane. The acetonitrile blending procedure using a volume correction is an adequate substitute for the exhaustive extraction procedure for recovering absorbed PCB residues in carrot roots. After determining internal dieldrin residues in five crops using four extraction procedures, Caro (1971) recommended blending with acetonitrile-water (65 + 35) rather than anhydrous acetonitrile for extracting roottranslocated pesticide residues in plants. The volume-corrected acetonitrile data for the two'1972 and one 1973 sampling dates are in Table III. Using the corrected acetonitrile data, the ratios of the "ppm" values of peak ltpeak 10, peak 4:peak 10, peak 5:peak 10, and peak 8:peak 10 were calculated and are given in Table IV. Material composing peak 1 was absorbed at five to eight times the rate of that from peak 10. The implications of this information are discussed by Iwata et al. (1974). The distribution of the PCB residues in the mature carrot root has been reported (Iwata el al. 1974); the peel, comprising 149c of the mature carrot weight, contained 97% of the residues. Similar results have been observed with organochlorine pesticidal residues. Hermanson et al. (1970) reported that peeling of carrots removed 50 to 80% of endrin residues. Localization of aldrin, dieldrin, heptachlor, and heptachlor epoxide in the carrot peel was reported by Fox el al. (1964). Lichtenstein et al. (1965) showed that considerable differences in the distribution of residues in the carrot root existed for five varieties field grown in aldrin or heptachlor treated soils. The sum of aldrin+dieldrin and heptachior + heptachlor epoxide residues found in DSW 379199 STLCOPCB4100077 11, . 20, . 20, . 20, 'Carrots seeded on July 31, 1972 and July 24, 1973. 'Figures in parentheses uncorrected for PCBs theoretically lost due to extract unrecovered from carrot pulp. Rc-extraction of pulp after CH.,CN extraction. 'Whole carrot root. Duplicate samples. A 52 Y. Iwata and F. A. Gunther ^3 "X3 Q C s: O k, co <rj o k* k. V o o -S t<n2 a ^2 k. O <N k. o k. X <v s 03 H 00 cn CM W '--' o <__s cn CJ 00 CM CM X w- N--' n O' 00 ri m CM 'W N--1" cn q cn m c'wn- CM m CM N--1" \o . CM cn in cn m cn CM r- o CM CM m CM CM o CM CM CM q cTf m o cn cn c- vO CM q OO' cn CM o cn CM ^tX/i 05 4> Q. u 00 2 Ck cs u CL E k V) VI C3 w> u o /---s Ck k S Tf 2 w 0) Pi in q in n s--' cn Tf m r- cn m r- in w /"s. VO n in rf s-^ w" d q in Tj- q VO d in in cn r- m r- -- in d o cn rt c- o rt q q oo vd d vd vd o vO cn in d Tj- d in rf r~~ NO On NO w /^S CM o in c- in ww r- d --d * 'w^ n vO o r- On vd v--^ OO rf w O CM in cn r- r- in q ro CM o r- q cn Tf O rt o Tt CM d o 00 in 00 in o in in vd oo d ON 00 CM vd d d in cn O --O m q o^ r- On vd /*"V On /^*v vd X cr nT o cn w C oo d o o r- o d CM d X oo O n q 00 CM o d NO q o r- q o CM cn o cn CM CM q CM n cn -- vd ON d d r- s m ON <N ww ,__^ CM 00 CM s--' CM r- o w m w CM > /__s o in ^t CM CM w CM w - o o cn CM * On cn ---- q CM ^t CM --< CM cn -- o CM CM CM cn CM CM CM o o n cn m Tfr -- gj o *o t5 _e C3 U E W o O 43 X> 2; 2: 2 M 2 u u U ?3 U XJ X re X X u u u UJ u o O X> 6 X> 222 t/i 3 2 222 c/: 3 2 U U U C3 U a U U C3 U X X X JZ X ` X X X JZ X X U u u UJ U u u u LU u o O X> 2 Z2 U u CJ yi 3 C3 2 U X X X JZ X X uuuWu " (C *E, wE Q 03 (A a. CM r-~ Os CM r-~ On o' CM - > ocj O 2 < cn cO' CM r-- On CM rON CM > t; > oO CJ o 22 CQ m r- CM CM r- On O' O' cm" > J> oo o o 22 u cn r- ON CM c O' CM rOn CM* > '> oo CJ o 22 D cn rOn CM > O 2 52 ! 0S\N 37920 STLCOPCB4100078 n CN p 00 rn Translocation of PCBs into Carrots Table IV. Ratio of "ppm" values found in carrot roots. Sample October 1972 November 1972 November 1973 Peak 1 Peak 10 8.60.7 6.7 0.6 5.3 0.4 Peak 4 Peak 10 4.60.3 3.90.3 3.00.4 Peak 5 Peak 10 3.3 0.2 2.60.2 2.20.2 Peak 8 Peak 10 1.9 0.1 1.90.1 1.7 0.1 53 -- in in rr oo Bo p vn Tf NO the peel was 55 to 81% and 56 to 86%, respectively, of the residue recovered from the whole carrot. The percentages for the various peaks present in carrot roots with respect to the surrounding soil for October 1972, November 1972, and November 1973 samples are in Table V. The residue level of peak 1 in one g of carrot root is 30 to 50% of that found in an equal weight of surrounding soil, while the residue of peak 10 in carrots is only 3 to 4% of that in the surrounding soil. Greater translocation of residues would be expected from soil containing PCB's such as Aroclor 1221 which has a larger proportion of the lesser chlorinated biphenyls. The results of the study may be compared to studies on the translocation of organochlorine pesticidal residues from soil into carrots. Comparisons are approxi mate as variations in carrot variety (Lichtenstein et al. 1965, Hermanson et al. 1970), soil type, and soil residue concentration (Lichtenstein 1959, Harris and Sans 1972a and b) greatly affect the degree of translocation and. thus complicate compari sons. Earlier studies utilizing colorimetric, bioassay, and total chloride methods j often included metabolites in addition to the parent insecticide; residues, such as j dieldrin and heptachlor epoxide, may result either by translocation from the soil or j by formation from aldrin and heptachlor within the plant. V5 JH Z U ' u fN 3 Z4C1 _. co xU wo si O.Q 3. c C -cc TwJ n oCL -* oe CL i ' Lichtenstein (1959) reported that 9.3 times more lindane was present in carrot roots (13.9 ppm) than in the silt loam soil involved. At a higher soil application rate, Table V. Percentage of the PCB peaks found ("ppm") in carrot roots relative to the surrounding soil. Sample Gas chromatographic peak 1 4 . 5 8 10 >o z Ua .Ur.* ^> 4 -C b T3 i October 1972 . November 1972 November 1973 50 8 30 3 329 23 2 15 2 14 3 . 17 1 9.90.6 9.82.6 8.2 0.7 6.3 0.3 6.5 1.1 4.3 0.2 3.30.2 4.00.8 DSW 379201 STLCOPCB4100079 54 Y. lwata and F. A. Gunther i only twice as much lindane was found in the root (44.7) ppm as in the soil. Carrots grown on three soil types, treated with ten lb/acre of lindane two years earlier, contained 6.0 ppm of lindane when grown in a sandy loam (soil level 0.96 ppm), 2.4 ppm in a silt loam (soil level 0.90 ppm), and 0.4 ppm in a muck soil (soil level 1 6.66 ppm). DDT residues were absorbed by carrots from the soil to a lesser degree than lindane (Lichtenstein 1959). Carrots grown in a sandy loam soil contained 10.6 and 9.1% of the level of DDT (in ppm) found in the soil (23.1 and 261 ppm, respec tively). In a silt loam 7.3 and 1.03% of the amount found in the soil (32.3 and 322 ppm, respectively) was recovered from carrots. In a muck soil only 0.14% of the amount found in soil (775 ppm) was present in carrots. The availability of dieldrin (Harris and Sans 1972a) and heptachlor epoxide (Harris and Sans 1972b) residues in soil for absorption by carrots was reported to be proportional, not to the concentration of the insecticide, but to the organic content of the soil. The highest residue of dieldrin occurred in carrots grown in a sandy loam which contained the lowest amount of organic matter; the residue in the root (0.195 ppm) was 13% of that in the soil. Heptachlor epoxide residues in carrots grown in sand containing 0.9% organic matter were about 60 times those found in carrots grown in muck soil containing 51% organic matter; residues in the root (0.563 ppm) and foliage (0.123 ppm) were 30 and 0.7% of that in the soil (1.88 ppm). The endrin residues in six varieties of carrots after 142 days maturity varied from 1.2 to 4.0 ppm when grown in field plots containing 2.3 to 4.0 ppm of endrin (Hermanson et al. 1970). The soil type of the field plot used in this study was a sandy loam containing 0.6% organic matter. The low organic matter content of the soil probably contri butes to a greater absorption of PCB residues by the carrots from the soil. The translocation of PCB isomers from soil into carrots under similar circumstances is in the same order of magnitude as that of the more persistent organochlorine pesticides. Although no PCB component was concentrated in carrot tissue to the extent reported for lindane, the use of lesser chlorinated PCB mixtures such as Aroclor 1221 might approach such high levels. Foliage from the young carrots sampled on October 11, 1972 was removed from the roots, extracted with acetonitrile, and analyzed separately. The results are in Table VI; no correction for PCBs lost due to unrecovered extract was used, nor was the effectiveness of the blending procedure for removing PCB residues from foliage established. The foliage contained up to 2.5 ppm of PCBs, and the percentages of the various peaks present in foliage, with respect to the surrounding soil for peaks 1, 4, 5, 8, and 10, were 3.1 0.7, 2.20.3, 1.8 0.3, 1.40.2. and 0.90.1%. respectively. Thus, one g of foliage contained about 1 to 3% of the Aroclor 1254 present in one g of surrounding soil. DSW 379202 STLCOPCB4100080 l the soil. Carrots wo years earlier, level 0.96 ppm), :ck soil (soil level esser degree than ontained 10.6 and 261 ppm, respecsoil (32.3 and 322 snly 0.14% of the eptachlor epoxide was reported to be organic content of n in a sandy loam in the root (0.195 n carrots grown in ? found in carrots : root (0.563 ppm) ) (1.88 ppm). aturity varied from t.O ppm of endrin v loam containing :1 probably contrirom the soil. The circumstances is in rnlorine pesticides, the extent reported .roclor 1221 might was removed from The results are in was used, nor was udues from foliage the percentages of ng soil for peaks 1, 1. and 0.90.1%, : the Aroclor 1254 r Translocation of PCBs into Carrots oso rO-s a .C 'cCD, e3- So .&ao 4> 03 3 &w k a s; V. -- O SO -- oo n (S n o> o (N (N c4 UJ oa. Boa Os <N csi so o in -- Os ---- cn Tt O' OO <n c-i a CNrj O < ^3 c CM .9 -o w O z zz z u uu u k CkC -Vw X~ Xn Xr: X wS CJ u u u JZ WX W UJ >.> 3cr v . g8 8 S. Wa. (m3 c?3 4*-) T3 _oh *- 4> q Rjil WE c 4> z H ~co cccx. *oco CO . _ 3 1a/>5 Eu, e- O ~<U g = -a S3 o &> JV G. QE CO (N <N CN (N r- r-- C" r-- Os Os Os Os --* -- tt j o o o *o o oo o ri cn m r- r- r- rOs Os Os Os O rJ o C4 m cn H. > 4> o Z Cl > 4) o Z T3 3 cc 4) "O "8 `sS-'-oC "o>- uM2 g=M oou. > O CO r~Os .C c 00 *S a < ffl U Q O 55 wwrrv STLC0PCB4100081 I 56 Y. Iwata and F. A. Guntlier Foliage from both young and mature carrots was sampled from the 1973 crop and exhaustively extracted. The results (Table VI) are identical for the two sampling dates. The foliage contained up to five ppm of PCBs, and the percentages of the various peaks present in foliage, with respect to the surrounding soil for peaks 1,4, 5,8, and 10, were 6.1 1.6, 3.90.8, 3.1 0.6, 3.40.5, and 1.70.3%, respec tively. Thus, one g of foliage contained 2 to 6% of the PCB present in one g of surrounding soil. The ratio of peak Irpeak 10 for carrot root was 8.60.7 for October 1972, 6.70.6 for November 1972, and 5.30.4 for November 1973. whereas for foliage it was 2.70.2 for October 1972 and 2.40.4 for the 1973 crop. The smaller ratio for foliage suggests the foliar residues probably resulted from a combination of root sorption with subsequent translocation and residues from soil dust adhering to the foliage. About 0.1 g of soil dust at 87 "ppm" on the 6.1 g of foliage from a single plant sampled on September 1973 would account for all of the 1.7 "ppm" found for peak 10. Figure 1 shows the different PCB patterns which were obtained from soil, root, and foliage extracts. Webb and McCall (1973) have determined the weight percentage of each electron-capture glc peak from a 3% SE-30 column for one lot of Aroclor 1254. Their results do not necessarily apply to other lots of Aroclor 1254, nor to data obtained from a QF-1 column. Although retention times of corresponding peaks differed, the pattern of peaks obtained on the mixed column used in this study did not qualitatively differ from that obtained on a 3% SE-30 column. Assuming that peaks 1, 4, 5, 8, and 10 correspond to peaks designated by Webb and McCall (1973), as 47, 70, 84, 125, and 174, respectively, their weight percentages of Aroclor 1254 are approximately 6.2 (Cl4), 13.2 (25% Cl4, 75% Cl5), 17.3 (Cl5), 15 (70% Cl5, 30% Cl6), and 8.4 (Cl6), respectively. The "ppm" data given in Tables II, III, and VI can be expressed in more meaningful ppm values by multiplication by the appropriate weight percentage factor. Thus, peak 5, the most abundant PCB component by weight (17%) is present at about 8.7 to 17 ppm in soil containing 50 to 100 ppm equivalent of Aroclor 1254 (Table II). The major constituent PCBs in Aroclor 1254 have been characterized or predicted by Sisson and Welti (1971). Seven components of Phenochlor DP6 have also been reported (Tas and de Vos 1971, Tas and Kleipool 1972). The structures of 12 compounds present in Aroclor 1254, which consists mainly of tetra-, penta-, and hexachlorobiphenyl isomers, have been established by comparison of glc and infrared data with compounds of known 4 structure (Webb and McCall 1972). Conclusions The change in composition of Aroclor 1254 in soil was evident over a 23-month period. Dissipation appeared to parallel the degree of chlorination. The lesser chlorinated biphenyls are slowly being dissipated while the more highly chlorinated 1 biphenyls appear to be unaffected. PCBs are absorbed by carrot roots; increased 4 translocation was associated with decreased degree of chlorination. The extent of translocation of PCBs from soil into carrots was of the same order of magnitude as reported for some of the organochlorine pesticides. Since 97% of the root residue was i os**9204 STLCOPCB4100082 . the 1973 crop and the two sampling percentages of the soil for peaks 1, 4, .7 0.3%, respec- 'resent in one g of was 8.60.7 for : November 1973, 0.4 for the 1973 probably resulted a and residues from ppm" on the 6.1 g a account for all of patterns which ercentage of each . of Aroclor 1254. 1254, nor to data orresponding peaks :d in this study did run. Assuming that Webb and McCall sht percentages of IJ5), 17.3 (Cl5), 15 aia given in Tables v multiplication by _ost abundant PCB ; soil containing 50 onstituent PCBs in and Welti (1971). . (Tas and de Vos Dresent in Aroclor enyl isomers, have mpounds of known r.t over a 23-month r.ation. The lesser highly chlorinated ot roots; increased ion. The extent of er of magnitude as ne root residue was 1 , rrtTT Translocation of PCBs into Carrots 57 found in the peel, very nttIe_tiansIocalion occurred in the plant tissue. Small amounts of PCBs were founcTTn the carrot foliage; the PCB composition suggested foliar contamination by soil dust. Thus, in plants where root absorption is minimal, contamination of plant foliage by soil dust is possible. Behavior of other chlorinated PCB mixtures can be predicted from the results using Aroclor 1254. Acknowledgments The assistance of H. Nakakihara and M. E. Diisch is gratefully acknowledged. Carrots were seeded and grown by Agricultural Operations, UCR. This work was partially supported by Regional Research Project W-45. References Bertuzzi, P. F., L. Kamps, and C. I. Miles: Extraction of chlorinated pesticide residues from nonfatty samples of low moisture content. J. Ass. Offic. Anal. Chemists. 50, 623(1967). Caro, J. H.: Comparison of four extraction procedures for root-translocated dieldrin in maize, kale, alfalfa, and wheat. J. Ass. Offic. Anal. Chemists 54, 1113(1971). Edwards, R.: The polychlorobiphenyls, their occurrence and significance: A review. . Chem. & Ind. (London) 47, 1340(1971). Fishbein, L.: Chromatographic and biological aspects of polychlorinated biphenyls. J. Chromatog. 68, 345(1972). Fox, C. J. S., D. Chisholm, and D. K. R. Stewart: Effects of consecutive treatments of aldrin of heptachlor on residues in rutabagas and carrots and on certain soil arthropods and yield. Can. J. Plant Sci. 44, 149(1964). Gustafson, C. G.: PCB's--Prevalent and persistent. Environ. Sci. Technol. 4, 814(1970). Harris, C. R., and W. W. Sans: Absorption of organochlorine insecticide residues from agricultural soils by root crops. J. Agr. Food Chem. 15, 861(1967). Harris, C. R., and W. W. Sans: Behavior of dieldrin in soils: Microplot field studies on the influence of soil type on biological activity and absorption by carrots. J. Econ. Enlomol. 65, 333( 1972a). Harris, C. R., and W. W. Sans: Behavior of heptachlor epoxide in soil. J. Econ. - Entomol. 65, 336( 1972b). Hermanson, H. P., L. D. Anderson, and F. A. Gunther: Effect of variety and maturity of carrots upon uptake of endrin residues from soil. J. Econ. En tomol. 63, 1651(1970). _ 1 0*N**5 STLCOPCB4100083 ] 58 Y. Iwata and F. A. Gunther Holden, A. V.: Source of polychlorinated biphenyl contamination in the marine environment. Nature 228, 1220(1970). Iwata, Y., W. E. Westlake, and F. A. Gunther: Varying persistence of poly chlorinated biphenyls in six California soils under laboratory conditions. Bull. Environ. Contam. Toxicol. 9, 204(1973). Iwata, Y., F. A. Gunther, and W. E. Westlake: Uptake of a PCB (Aroclor 1254) from soil by carrots under field conditions. Bull. Environ. Contam. Toxicol. 11, 523 (1974). Jensen, S.: The PCB story. Ambio 1, 123(1972). Lichtenstein, E. P.: Absorption of some chlorinated hydrocarbon insecticides from soils into various crops. J. Agr. Food Chem. 7, 430(1959). Lichtenstein, E. P., and K. R. Schulz: Residues of aldrin and heptachlor in soils and their translocation into various crops. J. Agr. Food Chem. 13, 57(1965). Lichtenstein, E. P., G. R. Myrdal, and K. R. Schulz: Absorption of insecticidal residues from contaminated soils into five carrot varieties. J. Agr. Food Chem. 13, 126(1965). Mills, P. A., J. H. Onley, and R. A. Gaither: Rapid method for chlorinated pesticide residues in nonfatty foods. J. Ass. Offic. Anal. Chemists 46, 186(1963). Mumma, R. O., W. B. Wheeler, D. E. H. Frear, and R. H. Hamilton: Dieldrin: extraction of accumulations by root uptake. Science 152, 530(1966). Nisbet, I. C. T., and Sarofim: Rates and routes of transport of PCB's in the environment. Environ. Health Perspectives 1, 21(1972) Nishikawa, K., T. Kaga, and M. Aizu: Kanemi Yusho (Kanemi rice oil disease). In J. Ui (ed): Polluted Japan, pp. 21-24. Tokyo: Jishu-Koza (1972). Peakall, D. B.: Polychlorinated biphenyls: Occurrence and biological effects. Re sidue Reviews 44, 1(1972). Pesticide Analytical Manual, Vol. I. Food and Drug Administration, Washington, D.C., Rev. April (1971). Reynolds, L. M.: Polychlorobiphenyls (PCB's) and their interference with pesticide residue analysis. Bull. Environ. Contam. Toxicol. 4, 128 (1969). Reynolds, L. M.: Pesticide residue analysis in the presence of polychlorobiphenyls (PCB's). Residue Reviews 34, 27 (1971). Saha, J. G., B. Bhavaraju, Y. W. Lee, and R. L. Randell: Factors affecting extraction of dieldrin-1:|C from soil. J. Agr. Food Chem. 17, 877(1969). Schupan, W.: Riickstiinde von Aldrin und Dieldrin in Wurzeln von Mohren (Dcuicits j carota L.) und ihr Einfluss auf den biologischen Wert. Z. Pflanzenkr. Pflan zenpathol. Pflanzenschutz. 67, 340(1960). J Selikoff, 1. J. (ed.): Polychlorinated biphenyls--Environmental impact. Environ, i Res. 5, 249(1972). 1 DSW 379206 STLCOPCB4100084 "ion in the marine ersistencc of polvry conditions. Bull. 3CB (Aroclor 1254) Contam. Toxicol. .an insecticides from W59). :r>tachlor in soils and em. 13, 57(1965). r:ion of insecticidal '. Agr. Food Chem. ad for chlorinated ~.nal. Chemists 46, Hamilton: Dieldrin: 2. 530(1966). rt of PCB's in the rice oil disease). In :a (1972). . oaical effects. Re lation. Washington. race with pesticide (1969k : alychlorobiphenyls Factors affecting 17. STT 1^69). n Mdhren iDciitcus Pflanzenkr. Pflan- impact. Environ. Translocation of I'CBs into (.allots Sisson. D., and 1). Welti: Structural identification of polychlorinated hiphcnvls in commercial mixtures hy gas-liquid chromatography. nuclear magnetic reso nance, and mass spectrometry. J. Chromalogr. 60, 15(1971). Tas, A. C., and R. H. de Vos: Characterization of four major components in a technical polychlorinated biphenyl mixture. Environ. Sci. Technol. 5, 1216(1971). Tas, A. C., and R. J. Kleipool: Characterization of components of technical polychlorinated biphenyl mixtures. Bull. Environ. Contam. Toxicol. 8. - 32(1972). Taylor, A. W., H. P. Freeman, and W. M. Edwards: Sample variability and the measurement of dieldrin content of a soil in the field. J. Agr. Food Chem. 19, 832(1971). Webb, R. G., and A. C. McCall: Quantitative PCB standards for electron capture gas chromatography. J. Chromatogr. Sci. 11. 33(1973). Webb, R. G., and A. C. McCall: Identities of polychlorinated biphenyl isomers in Aroclors. J. Ass. Offic. Anal. Chemists 55, 746(1972). Wheeler, W.B., D. E. H. Frear, R. O. Mumma, R. H. Hamilton, and R. C. Cotner: Quantitative extraction of root-absorbed dieldrin from the aerial parts of forage crops. J. Agr. Food Chem. 15, 227(1967). Manuscript received May 1, 1974; accepted July 29, 1974. osVg 379207 STLCOPCB4100085