degradation of pcp in soils
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This article was downloaded by: [Laurentian University]On: 06 October 2014, At: 06:04Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK
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Degradation of PCP in soilsShozo Kuwatsuka a & Michiyo Igarashi a ba Department of Agricultural Chemistry , NagoyaUniversity , Nagoya , Japanb Agricultural Chemicals Inspection Office, Ministryof Agriculture and Forestry , Kodaira, TokyoPublished online: 19 Apr 2012.
To cite this article: Shozo Kuwatsuka & Michiyo Igarashi (1975) Degradationof PCP in soils, Soil Science and Plant Nutrition, 21:4, 405-414, DOI:10.1080/00380768.1975.10432656
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Soil Sci, Plant Nulr., 21 (4), 405-414, 1975
DEGRADATION OF PCP IN SOILS
II. The Relationship between the Degradation of PCP and the Properties of Soils, and the Identification
of the Degradation Products of PCP'"
Shozo KUWATSUKA and Michiyo lGARASHl**
DePartment of Agricultural Chemistry, Nagoya University, Nagoya, JaPan
Received May 26, 1975
In laboratory experiments, the degradation of PCP in soil with regard to the relationship to soil properties was studied under upland and flooded conditions using gas-chromatographic techniques. The degradation products and their behavior were elucidated by using 10 diCferent soils collected from rice fields and adjacent upland fields and one sample of a subsoil from the forest. The results are as follows: 1} The degradation of PCP in soils was faster under fiooded conditions than upland conditions. 2) The degradation under flooded conditiont was more rapid in soils collected from rice fields than in those from adjacent upland fields, Tbe reverse was true under upland conditions. 3) The degradation rate was highly correlated with the organic matter content of the soil. Almost 100% of the PCP remained In the ~tubsoil sample even after 50 days of Incubation. The rate wu slightly correlated with the clay mineral com· position, free iron content, phosphate absorption coefficient and C.E.C., but hardly at all with texture, clay content, degree of base saturation, soil pU and available phosphorus content. 4} As the degradation products of PCP, 3 tetrachlorophenols, 4 or 5 trichlorophenols and PCP methyl ether were detected, PCP methyl elher and 2, 3, 4, 5-tetrachloro• phenol were the major products, but the amount of the latter varied greatly during the course of Incubation.
PCP (pentachlorophenol) was used as a major herbicide for the rice crop in paddy fields In Japan (or two decades from 1950. The annual production or usage of the active ingredient in 1970 was about 15,000 tons, which was about one fourth
• The main part of ~his study was presented In Ann. Meeting of Soc. Sci. Sol! and Manure, Japan, Oct. 1971 { 16 ).
•• Present addfess: Agricultural Chemicals Inspection Office, Ministry of Agriculture and Forestry, Kodaira, Tokyo,
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406 S. KUWATSUKA and M. IGARASHI
of the total amount of all pesticides used in Japan. Because of its fish toxicity, its consumption has decreased rapidly since 1971. However, PCP is still in use both as a herbicide and fungicide for agricultural purposes, and as an antiseptic reagent for lumber preservation. The acetate and barium salt of PCP have been used as fungicides against Pyricularia oryzae on the rice crop.
Although PCP has been used in such large amounts, its fate and behavior in soil environments have been left unascertained for a long time. The adsorption and movement of the chemical in the soil was studied by NosE et al. (2, 3) and TSUNODA ( 4), its photodegradation, by MUNAKATA et a/, (5-7) and CROSBY et al. ( 8 ). The degradation of PCP in soils, however, was left unclarified.
By 1970, investigations on the subject had been carried out by WATANABE ( 9, 10), ASO and SAKAMOTO, (11), TSUNODA (12), SUZUKI and NOSE (13), and YOUNG ( 14 ), Those studies, however, did not give much information on the fate and behavior of PCP in soils with regard to the degradation products, the relationship of the degradation process to the soil properties and environmental conditions of the soil, and the residual amount or the degradation rate of the chemical at field application levels.
Recently, IDE et a/. ( 15) and the present authors ( 16) concurrently found that the degradation products of PCP in soils consist of dechlorinated compounds. Moreover, SUZUKI and NosE ( 17) found that a species of bacteria isolated from soii transformed PCP into its methyl ether and into tetrachlorohydroquinone dimethyl ether in the culture medium.
The present studies were designed to elucidate the fate and behavior of PCP in soils, particularly, to clarify the degradation pathway, the relationship of soil properties and environmental t.:onditions to the degradation process, and the mechanism of degradation. In the previous paper ( 1 ), a simple and accurate method was reported for analyzing PCP and its dechlorinated compounds in soils. In the present paper, the relationship between soil properties and the degradation of PCP in soils under upland and flooded conditions was investigated using samples of 11 different soils. The identification of the degradation products of PCP in upland and flooded soils and their behaviors in the course of time are also reported.
MATERIALS AND METHODS
1) Reagents. l'CP (mp 189-19l0C), 3 tetrachlorophenol(TeCP)s and 6 trichlorophenol(TrCP)s were used with 2, 4, 6-tribromophenol(2, 4, 6-TrBP) as the internal stand:lrd as described in the previous paper ( 1 ). J>CJl methyl ether (PCP· Me, pentachloroanisol, mp 106°C) was prepared by methylating PCP with diazomethane in ether and recrystallizing twice from methanol,
2) Soils. Eleven different soil samples of various soil types were collected in winter from the arable layer in rice fields and the adjacent upland fields in five different areas, and from the sublayer of a forest red yellow soil. The latter was used as a blank soil in studies on organic materials or microbial activity, The physicochemical properties of these soils are shown in Table 1.
3) Soil conditioning (preincubati01z of soils), Before PCP was applied to the soil, soil samples were preincubated in order to simulate field conditions. (l) For the study on the influence of soil properties on PCP degradation, air-dried fine soil
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Degradation of PCP in Soils (Il) 407
passed through a 2 mm sieve was used, to ensure that the properties of each soil were kept constant for the different experiments conducted at different times.
Fifty grammes (dry weight basis) of the air-dried and sieved soil sample was placed in a 100 ml Erlenmeyer flask. Water was added up to 60% of the maximum Water holding capacity to simulate upland soil conditions, or up to 250% to simulate flooded conditions. The flask was covered with aluminum foil, and incubated at 30oC in the dark for 5 weeks. The amount of water lost through evaporation,
Table 1. Properties of soil samples used.1'
A b. Source Clay pH Total..C C. E. C. Clay mineral Texture content (IIaO) (me/100 g) (%) (%)
-~-- __ __,_ ___ T Tochlgi, paddy Allophane SiC 5.4sl 5.81 7.87 40.5 T' Tochlgi, upland Allophane SiC 4.5u 6.01 7.52 46.4 N Nagano, paddy Montmorillonite CL 20.5 4.60 1.81 21.3 N' Nagano, upland Montmorillonite CL 21.0 5.22 1.45 24.3 s Shizuoka, paddy Kaolin cr. 22.7 5.91 3.64 19.9 S' Shizuoka, upland Kaolin CL 22.8 4.83 1. 91 13.2 A Anjo, paddy Kaolin SCL 23.1 5.83 1.93 13.6 A' Anjo, upland Kaolin CL 27.5 6.40 1. 23 15.2 K Kikugawa, paddy Kaolin CL 22.4 6.07 1.21 14.7 K' Kikugawa, upland Kaolin CL 15.4 4.74 1.04 13.0
II Hlgashlyama (D·C) Kaolin CL 19.1 4.58 0.04 5.0
= -- =-Phosphate
A b. Source Clay mineral Texture Free Iron Available absorption phosphorus coefficient
(%) (mg %) (PliO~mg) ----~--
T Tochigl, paddy Allophane SiC 1.96 17.4 1,620
T' Tochigl, upland Allophane SiC 2.45 16.4 1,886
N Nagano, paddy Montmorlllonite CL 1.18 13.2 560 N' Nagano, upland Montmorillonite CL 1.83 15.2 544 s Sh!zuoka, paddy Kaolin CL 1. 76 13.8 756
S' Shizuoka, upland Kaolin CL 1.30 8.6 156
A Anjo, paddy Kaolin SCL 1. 25 10.3 504
A' Anjo, upland Kaolin CL 1.62 10.3 412
K Klkugawa, paddy Kaolin CL 0.94 9.1 292 K' Kikugawa, upland Kaolin CL 0.78 10.2 212
II II!gashlyama (U·C) Kaolin CL 1. 02 5.8 96 ~---------,...,~ ·--· _ ...... --~---------~·-·--. -~ ............ --------·-----------·-----~-------·--·- ----..... ~ ... ll Analytical methoda used were described In the previous report ( J ). Values are shown on
oven-dry soil basis. •> Dispersion by supersonlficat!on (pU 4.0). The values are not correct because of the difficulty
of dispersion.
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408 S. KUWATSUKA and M. IGARASHI
which was measured by weighing the flask, was restored by the addition of water once a week. (ii) For the stucly on the clegraclation product, moist or unclriecl soils crushed well and passecl through a 2 mm sieve were employed, because it is more important in such experiments to maintain the microbial characteristics of the soil samples. The sieved soil samples were stocked in air-tight bags at soc In the dark until they were used for the experiments.
Sixty grammes (50 g based on dry weight) of the sample of Anjo soil was incubated in a flask using the procedure described above except that the preincuba· tion was carried out for 2 weeks.
4) Application and incubation of PCP. For the study on the influence of soil properties, 5 mg of PCP solution in 0.5 ml of 0.1 N NaOH was added to the pre· incubated soil (100 ppm ·based on soil dry weight) in a flask. For the study on the degradation products, 0,5 mg of PCP (10 ppm) was applied to the soil. The soil was mixed well with a glass rod, and the flask was covered with aluminum foil. The sample was incubated for 30 min, 5, 10, 20, 30, or 50 days in the dark. The PCP and the degradation products were then analyzed. During incubation, the water lost through evaporation was restored once a week. ·
5) Analysis of PCP and the degradation products. The analytical method for determining PCP and its dechlorinated compounds in soils was reported in the previous paper ( 1 ). Because the paper was written in Japanese, the analytical method is outlined here. Fifty grammes (dry weight basis) of the soil containing PCP was placed into a 500 ml bottle. To each soil sample kept under upland conditions, about 50 ml of water was added. The mixture was acidified with cone. HCl, shaken horizontally with 200 ml of benzene for 4 hr, and allowed to stand for a while. The benzene extract was washed with water and dried with NaaSO,.
When only PCP was determined, an aliquot of the benzene solution was injected into the gas-chromatograph after adding 2, 4, 6-TrBP as an internal standard. Using this solution, it was possible to determine most of the degradation products as well as PCP, but it was not possible to separate PCP-Me and 2, 4, 6-TrCP, both of which are degradation products.
The se.parate determination of PCP-Me from polychlorophenols necessitated further fractionation of the extract. A certain volume of the benzene extract solu· tion was shaken with 0.5 N NaOU solution. The benzene layer was washed with water, 2,4, 6-TrBP was added, and the solution was chromatographed to determine PCP-Me. The NaOII layer was acidified with cone. IICl and extracted with a certain volume of benzene, The benzene extract was washed with water, 2, 4, 6-Trlll' was added, and the extract was analyzed by gas-chromatography to determine PCP and other polychlorophenols.
Gas-chromatography was carried out using a glass column packed with D-29 (DEGS 1% + IIaPO, 1%) on chromosorb W at 160"C for PCP or 140°C for the other degradation products. The gas-chromatograph was equipped with an electron capture detector.
The recoveries of PCP and other polychlorophenol products were more than 95% from 3 different soils containing these chemicals at 1 ppm level based on soil dry weight (I). The PCP at 0.01 ppm level was also easily determined by chang· ing the volume of either the benzene solution extracted with 0.5 N NaOH, the NaOII solution, the benzene solvent used for reextracting the NaOII solution, or
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Degradation of PCP In Solis (II) 409
the volume of extract injected into the gas-chromatograph. The identification of the degradation products was carried out by co·chromatog·
raphy with authentic samples of PCP, 2, 3, 4, 5·, 2, 3, 4, 6-, and 2, 3, 5, 6-TeCPs, .2, 3, 4·, 2, 3, 5-, 2, 3, 6·, 2, 4, 5·, 2, 4, 6·, and 3, 4, 5· TrCPs, and PCP·Me.
RESULTS AND DISCUSSION
.I. /Jcgradati01z of PCP The patterns of PCP degradation in 11 different soils are shown in Fig. 1. The
-degradation rate varied according to the kind of soU. In the arable soils, the half· life of PCP ranged from 10 to 70 days (average 30 days) under flooded conditions .and from 20 to 120 days (average 50 days) under upland conditions. The period of time required to degrade 90% of the PCP present was 30 days or more under flooded conditions, and 50 days or more under upland conditions. When PCP was -applied to Higashiyama soil, which is a forest subsoil containing trace amounts of organic matter, almost 100% remained even after 50 days subsequent to application under both water conditions. A similar result had been reported by WATANABE { 9) and IDE et a(. (15) that PCP disappeared rapidly in mature paddy fields, but hardly at all in a newly reclaimed field and in soil collected from an immature paddy field. These results suggest that PCP degradation is related to microbial activity in the soil. The degradation of PCP in steriliz:ed soils will be reported in a subsequent paper.
Under flooded conditions, the degradation was more rapid in the soil obtained from a rice field than in the soil from the adjacent upland field for all paired .samples tested. Under upland conditions the degradation was more rapid fn soils -obtained from upland fields for each sample pair. These results suggest that PCP·degrading microorganisms present in upland or paddy fields survived alter air-drying of the samples, and that they are more active in degrading PCP when placed in ·environments to which they are adapted. Also, it may be suggested that PCP is degraded by several kinds of microbes which are accustomed either to upland or .to flooded conditions.
Flooded conditions Upland conditions
0~o-T:l0~-:2~0-;;;.:=4;0=~50 0 10 20 30 40 50 Incubatl on ·period (days)
Fig. 1. PCP degradation In varlout soils under flooded and upland conditions.
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410 S. KUWATSUKA and M. IGARASHI
2, The relationship between soil properties and the degradation of PCP in soil Figure 2 shows the relationship between the carbon content of the various
soils and the residual percentage of PCP in these soils after certain periods of incubation. Under flooded conditions, the degradation rate was largely related to the organic matter content, especially in the case of kaolinic soils. In montmoril· lonitic Nagano soils, the PCP disappeared more slowly at the earlier stage and more rapidly at the later stage of incubation. Table 2 shows the relationship of the PCP degradation rate to several soil properties of the various soils for various incubation periods. Texture, clay content, degree of base saturation, soil pH, and phosphorus content were not found to be closely related to the degradation rate of
5days
lOdays
20days
30days
50 days
3 4 5 6 Totai-C (%)
7
r'r :I
8
Fig. z. Relationship between degradation rate of PCP and organic matter content of vadou~ ~oils for different incubation periods. II, lligashiyama; N, Nagano paddy; N', Nagl)no upland; A, Anjo paddy: A', Anjo upland; S, .Shlzuoka paddy; S'. Shlzuoka upland; T, Tochigi paddy; T', Tochigi upland.
Table 2. Correlation coefficients between degradation rate of PCP and properties of soi!s.U
Flooded conditions Upland conditions Incubation period (days) -------------~--------------- ----------------------------
5 10 20 30 5 10 20 30
Soil property Total carbon content Clay contenta>
·----·--------------- -------------•••0.839 ***0.815 ••0.625 •••0.827
0.182 0.457 0.352 0.432 ••o.s11 ••o.s14 •o.539 o.383
0.046 0.264 0.194 0.152 C.E.C. •••0.831 *0.574 *0.599 *0.525 **0.926 ••o.763 0.368 0.333
Available phosphorus o. 392 o. 365 •o. 499 •o. 589 •o. 675 •o. 642 o. 144 0. 19S content Free Iron content pii (Ha0)
•••o.889 •0.633 •••o.a58 0.409 0.392 •0.630 0.420 0.432
0.091 0.597 0.358 0.387 0.184 0.539 0.444 0.153
Phosphate absorption u•o. 877 •o. 730 ***0. 908 •••o. 922 h*O. 937 **0. 821 0. 368 0. 253 coefficient
n .. ,.., ••, "' indicate slgnlticance levels of 0.1, 1, and 59'o, respectively. u Data on Tochigl soils under flooded and upland conditions were not included.
Applied amount-residual amount 1 3> Degradation ratec- ---- --··-···------- --------··-···---·----··X----------------
Applied amount Incubation period
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Degradation of PCP in Soils (II) 4H
PCP, Cation exchange capacity, free iron content, and phosphate absorption coefficient were related but to a smaller extent than organic matter content.
Many studies on the relationship between the degradation of chemicals and soil properties have been reported. Organic matter content, cation exchange capacity, clay mineral composition, clay content and soil pH are related to the degrada· tion of chemicals. In many cases, the organic matter content is the factor that is most related to the degradation rate (18, 19). In this report, the degradation of PCP was also found to be largely related to organic matter content and less to cation exchange capacity and pH. Furthermore, no degradation was found in lligashiyama soil which contains only trace amounts of organic matter. These results suggest that microorganisms play an important role in the PCP degradation in soils.
3, The analytical method and atborptitm of PCP on soil particles In general, it is hard to say whether a decrease in the amount of a chemical
in the soil, measured by some analytical method, is caused by the degradation of the chemical or by its extremely strong adsorption on soil particles to the point that the chemical cannot be extracted from the soil by the method used, Even if a chemical can be recovered 100% from the soil shortly after its addition, this is not sufficient to ensure that no adsorption takes place. Recoveries after long periods of incubation often vary largely among extraction methods which claim recoveries of 100% in the initial time. However, almost 100% of the PCP was recovered even after 50 days of incubation in kaolinic Higashiyama subsoil by the analytical method used In this study. This means that not only PCP in Higashi· Yama soil but also residual PCP in other soils may be extracted completely with benzene by the addition of IICl, although PCP is adsorbed on soil particles ( 3, 1: ). At least, it can be said that PCP adsorbed on kaolinic clay mineral is recovered completely by this method even after a long period of incubation.
In montmorillonitic Nagano soils, the residual amount after 50 days of incuba· tion under flooded conditions was low. Montmorillonitic soils often strongly adsorb many chemicals into the clay lattice. In this study, the residual amount of PCP in Nagano soils was measured up to 30 days incubation under flooded conditions and during the whole period under upland conditions than kaoUnic or volcanic ash soils, This probably means that the PCP in the clay lattice is also recovered by this analytical method.
Another problem is the adsorption on humic substances. The extraction of PCP from Tochigi soil needed a longer period of time. Tochigl soil is a volcanic ash soil and contains much more humic substance than other mineral soils, Under upland conditions, 15% of the PCP added to Shizuoka upland soil containing 29{) carbon, and 23% of the PCP added to Tochigi upland soil containing 7.4% carbon was recovered after 50 days of incubation. Also, under flooded conditions, 20% o! the PCP added was recovered from Shizuoka rice field soil containing 3.7% carbon, and 159'o from Tochigi upland soil. The residual PCP concentration was high up to 10 days of incubation in Nagano soils kept under flooded conditions. These examples may suggest that PCP adsorbed on humic substances was also easily extracted into bem:enc by this analytical method.
Furthermore, this analytical method does not involve a methylation process,
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Therefore, PCP and the dechlorinated products can be determined without their methyl ethers. It is more strict than the method reported by IDE et al. ( 15) in which ·PCP was determined in a mixture together with PCP·Me.
4. Degradation products of PCP in soil To determine the degradation products of PCP in the soU, Anjo soil was used
without air-drying, in order to avoid changes in microbial and chemical properties caused by air-drying. The clay mineral composition and organic matter content of Anjo soil are most common among the rice fields in Japan.
Many peaks caused by PCP degradation appeared on the gas-chromatogram. As an example, a chromatogram of the degradation products in the acid fraction, on the 5th day of incubation under flooded conditions is shown in Fig, 3. The new peaks resulting !rom the incubation of PCP were identical with those of
2,3,6·TrCP
2,4,6-TrCP
Internal atandard subat11nce 2,4,ti·TrBP
10 15 20 Retention time (min)
Fig. 3. Gas-chromatogram of PCP degradation products In acid fraction after 5 days"!_incubatlon In Anjo 110il.
100 lOppm, ao·c • 2,3,4,5·TeCP • PCP-Me o 2,3,6-TrCP 'X 2,4,6·TrCP A 2,4,5-(and/or 2,3,4·) TrCP
i~ g
"'2/\ /\ ~ 3~•, ,.-. Upland
I;Q 1 I P..}]/ '-0 '~-.,_-~__..____.,__.,.. 41 ,/«:~. :-:-:.:.~.·.::.\..-,. .... ----.0 - c::l Q :;.A., ui:IJ.l~Mu;,:.llnu,..,.n ......
10 20 30 40 50 10 20 30 40 50 Incubation period (days)
Fig, 4. Changes ln amounts of PC? and degradation products during Incubation under flooded and upland conditions.
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Degradation of PCP in Soils (Il) 413
2, 3, 4, 5·, 2, 3, 4, 6·, and 2, 3, 5, 6-TeCPs, 2, 3, 5-, 2, 3, 6-TrCPs, 2, 3, 4· and/or 2, 4, 5-TrCPs, and 2, 4, 6-TrCP. 2, 3, 4-TrCP and 2, 4, 5-TrCP were not separable because they have the same retention time. 3, 4, 5-TrCP was not detected. PCP-Me was detected in the neutral fraction. A large amount of it appeared at the same retention time as 2, 4, 6-TrCP in the acid fraction.
Figure 4 shows the changes in the amounts of residual PCP and the compounds Produced in soils under upland and flooded conditions. 2, 3, 4, 5-TeCP and 2, 3, 6-TrCP, and 2, 4, 6-TrCP and PCP-Me were major products and other compounds were detected only in small or trace amounts. 2, 3, 4, 5-TrCP, a major product, show:ed two or three peaks during the course ·of incubation as shown in Fig, 4. The result was replicated by repeating the experiment.
The separate determination of 2, 3, 4·TrCP and 2, 4, 5-TrCP was not investigated further, because both compounds, whether appearing singly or together on the chromatogram, were detected only in trace amounts. Furthermore, these products Were though to be of little importance.
IDE et al. ( 15) also found 2, 3, 4, 5-, 2, 3, 5, 6-, and 2, 3, 4, 6-tetrachloroanisols, 2, 3, 5· and 2, 4, 5-trichloroanisols, 3, 4- and 3, 5-dichloroanisols and 3-chloroanisol as methylated compounds of the products of PCP in incubated soil, but not 2, 3, 4·, 2, 3, 6·, and 2, 4, 6-trichloroanisols, In this study, 2, 3, 6- and 2, 4, 6-dichlorophenol as Well as 2, 3, 4, 5-tetrachlorophenol were determined in relatively large amounts. Dichloro- and monochlorophenols were not examined.
The appearance of all three isomers of tetrachlorophenol and 4 or 5 trichloro· phenols of 6 isomers as PCP degradation products suggests that the degradation in soil is accomplished not only through microbial action but also through chemical (non-microbial) reaction, although reaction by microbes is the major course. This problem will be discussed with the experimental results in a subsequent paper. The degradation process of PCP in soil will also be discussed In the paper.
Acknowledgement. The authors wish to thank Prof. K. Kumada of the authors' laboratory and Dr. S. Matsunaka of the National Institute of Agricultural Sciences, for their valuable advice and encouragement during this work. The authors are also grateful to Dr. A. M!ko· Bhlba, Nagano Prefectural Agricultural Experiment Station, Dr. A. Nakanishi, .1\lchl Prefectural Agricultural Experiment Station, Mr. II. Kato, Utsunomlya University, and Mr. K. Ishikawa, Kumlal Chemical Co. for their great help In collecting soU samples, and to Dr. n. Nishiyama, Ishihara Sangyo Kalsha, for the kind gift of 3, 4, 5·trichlorophenol.
This work was supported In part by grants from the Japan MinistrY of Education and the Japan Ministry of Agriculture and Forestry. .
REFERENCES
1) KuWATSUKA, S. and IGARASHI, M., Degradation of I'CP In soils (Part l) Quantitative analysis of PCP In ·lioil (In Japanese, Engllsh summnry), J. Sci. Soil Manur1, JaPan, (5, 321-326 (1974)
2) Nose, K., SuzuKl, T., and FuKUNAGA, K., J'entachlorophenal (PCP) adsorption on soil (Part 1) Variety of PCP adsorption, J. Sci. Soil .Manur1, Japan, :u, 243-246 (1963); (Part 2) Effects of humus, pll and exchangeable cations upon PCP adsorption, s.t, 291-295 (1963); (Part 3) Some correlations among rcp adsorption, heat of wetting and cation exchange capacity, 3!, 367-370 (1963)
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3) NosE, K., Vertical distribution of pentachlorophenol :applied on paddy field, J, Sci. Soil Manure, Japan, 35, 306 (1964)
4) TSUNODA, H., Pentachlorophenol (PCP) adsorption on soil (Part 1) Soil effect on PCP adsorption, and influence of PCP adsorption on the herbicidal efficiency of PCP, J, Sci. Soil Manure, JaPan, 36, 187-194 (1965)
5) MUNAKATA, K. and KUWAHARA, M., Photochemical degradation products of pentachloro• phenol, Residue Reviews, 25, 13-23 (1969)
6) KUWAHARA, M., KATO, N., and MUNAKATA, K., The photochemical reaction of penta• chlorophenol (Part 1) The structure of the yellow compound, Agr. Biol. Chern., 30, 232-238 (1966); (Part II) The chemical structures of minor products, ibid., 30, 239-244 (1966)
7) KUWAHARA, M., SHINDO, N., and MUNAKATA, K., The photochemical reaction of penta• chlorophenol (In Japanese, English summary), J, Agr. Chern. Soc. JaPan, 41, 169-174 (1970)
8) CROSBY, D.G., MOILANEN, K.W., NAKAGAWA, M., and WONG, A.S., Photonucleophilic reaction of pesticides, in "Environmental Toxicology" (Matsumura, F., Boush, G.M., and Misato, T., eds.) Academic Press Inc. Publishers, New York, 1972, pp. 423-431
9) WATANABE, I., Degradation of pentachlorophenol (PCP) by soil microorganisms, Soil and Microorganisms Japan, 14, 1-7 (1973)
JO) WATANABE, I. and HAYASHI, S., Degradation of PCP (pentachlorophenol) ln Soil (Part 1) Microbial depletion of PCP under dark and submerged conditions (In Japanese, English summary), J. Sci. Soil Manure, Japan, 43, 119-122 (1972)
11) Aso, S. and SAKAMOTO, K., Studies on behavior of pentachlorophenol (PCP) under paddy field conditions (Part 1) differences of the behavior of PCP among several soil types, J. Sci. Soil Manure, JaPan, 43, 119-122 (1972)
12) TSUNODA, II., Pentachlorophenol (PCP) derivatives as weed killers (Part 2) Movement and decomposition of PCP derivatives in soil, J. Sci. Soil Manure, Japan, 36, 200-202 (1965)
/3) SUZUKI, T. and NOSE, K., Decomposition of pentachlorophenol in farm soil (Part 1) Some factors relating to PCP decomposition, Pesticide and Technique Japan, 22, 27-30 (1971)
/4) YoUNG, U.C., The decomposition of pentachlorophenol when applied as a residual pre• emergence herbicide, Agron. J., 43, 504-507 (1951)
IS) IDE, A., NIKI, Y., SAKAMOTO, F., WATANABE, I., and WATANABE, H., Decomposition of pentachlorophenol in paddy soil, Agr. Bioi. Chern., 36, 1937-1944 (1972)
16) lGARASill, M. and KUWATSUKA, S,, Degradation of PCP In soil. Abst. Ann. Meet., J. Sci, Soil and Manure, JaPan, 17, 24 (1971)
17) SUZUKI, T. and NoSE, K., Decomposition of pentachlorophenol in farm soli (Part 2) PCP metabolism by a microorganism Isolated from soil, Pestl'cldo and Technique JaPan, 26, 21-24 (1971)
/8) HAMAKER, J,W., Decomposition, quantitative aspt:cts, in "Organic Chemicals In the Soil Environment" (C. I. Goring and J, W. Hamaker ed.), Vol, 1, Marcel Dekker, Inc., New York, 1972. pp. 253-340
19) HELLING, C.S., KEARNEY, P.C., and ALEXANDER, M., Behavior of pesticides in soils, in "Advan. Agron." (A.G. Norman ed.), Vol. 23, Academic Press Inc. Publishers, New York, 1972. pp. 147-240
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