Showing papers in "Archives of Environmental Contamination and Toxicology in 1976"
TL;DR: The two most toxic pyrethroids, RU-11679 and SBP-1382, were deactivated more rapidly in water solutions than natural pyrethrins, S-bioallethrin, dimethrin, andd-trans allethrin.
Abstract: The toxicity of natural pyrethrins and five pyrethroids was determined with coho salmon (Oncorhynchus kisutch), steelhead trout (Salmo gairdneri), fathead minnow (Pimephales promelas), channel catfish (Ictalurus punctatus), bluegill (Lepomis macrochirus), and yellow perch (Perca flavescens) The 96-hour LC50's in static tests at 12‡C ranged from 246 to 114Μg/1 of natural pyrethrins and from 0110 to 1,140Μg/1 of pyrethroids Two pyrethroids, RU-11679 and SBP-1382(R), were over 10 times more toxic than pyrethrum extract in the flow-through tests Coldwater species of fish were more sensitive than warmwater species to all the compounds Temperature (12–22‡C) influences the toxicity of natural pyrethrin and the pyrethroids The natural pyrethrin was more toxic to fish in pH 65 than in pH 95 water, but the toxicity of pyrethroids was not influenced in that pH range The two most toxic pyrethroids, RU-11679 and SBP-1382, were deactivated more rapidly in water solutions than natural pyrethrins, S-bioallethrin, dimethrin, andd-trans allethrin
72 citations
TL;DR: 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 and direct foliar contamination by soil dust is suggested.
Abstract: 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.
49 citations
TL;DR: Male Sprague-Dawley rats were fed a diet containing mixtures of polychlorinated biphenyls (PCB) isomers (Aroclor 1248, 1254 and 1262) at a concentration of 100 ppm in the diet for 52 weeks and during the subsequent 13 weeks the rats were placed on a control diet.
Abstract: Male Sprague-Dawley rats were fed a diet containing mixtures of polychlorinated biphenyls (PCB) isomers (Aroclor 1248, 1254 and 1262) at a concentration of 100 ppm in the diet for 52 weeks. During the subsequent 13 weeks the rats were placed on a control diet. Throughout the course of the experiment the animals ate well, were healthy in appearance and gained weight as rapidly as the control animals. Their hemograms were normal. In spite of the gross normalcy of these animals throughout the 52-week experimental period, clinical and morphologic examinations revealed distinct alterations. There was a decided increase in their total serum lipids and cholesterol and a transient increase in triglycerides accompanied by distinct morphological changes in the liver. Generalized liver hypertrophy and focal areas of hepatocellular degeneration were followed by a wide spectrum of repair processes. The tissue levels of PCB were greater in the animals receiving the higher chlorine mixtures. High levels persisted in these tissues even after the PCBs had been discontinued.
41 citations
TL;DR: Curves relating median lethal concentration to exposure time for each species exposed for more than 168 hr were sigmoid in shape and were characterized by a change in slope indicating a more rapid mortality rate after 96 to 168 hr toxicant exposure.
Abstract: Acute toxicity tests of selenium dioxide were conducted for 96 to 336 hr in intermittent-flow bioassay systems using six species of freshwater fish. The decreasing order of species sensitivity was: fathead minnow, flagfish, brook trout, channel catfish, goldfish, and bluegill. Curves relating median lethal concentration to exposure time for each species exposed for more than 168 hr were sigmoid in shape and were characterized by a change in slope indicating a more rapid mortality rate after 96 to 168 hr toxicant exposure. The 96-hr LC50 estimates ranged from 2.9 mg/L SeO2 for fathead minnow fry to 40.0 mg/L for bluegill juveniles.
36 citations
TL;DR: Groups of 30Xenopus laevis embryos, at “tail-bud” stage (Nieukoop-Faber stages 22–24) were exposed to 0.1–2 ppm concentrations of various pesticides for 1 to 10 days, and many of these embryos developed a slightly retarded trunk and tail only.
Abstract: Groups of 30 Xenopus laevis embryos, at "tail-bud" stage (Nieukoop-Faber stages 22-24) were exposed to 0.1-2 ppm concentrations of various pesticides for 1 to 10 days. The pesticides used were chloranil and dichlone (both are fungicidal and herbicidal); diquat (herbicide); and nabam (fungicide). The parameters examined were mortality, gross morphology, histology, and behavior. Chloranil (1.25 to 1.75 ppm) treated embryos showed abnormalities of the otolith, optic cup, and general pigmentation. Their movement was sporadically convulsive and they were unable to maintain proper balance. Dichlone (0.1 to 0.15 ppm) disrupted the development of the cephalic end of the embryo. Many of these embryos developed a slightly retarded trunk and tail only. These headless embryos lived for a time and were relatively lethargic. Diquat (0.75 to 2.0 ppm) administration reduced body size and pigmentation, and altered body shape. When embryos were treated with both 1.0 ppm of diquat and 2.0 ppm of nabam the integrity of myomeres and myocommata of the musculature was disrupted. The histological bases of these morphological and behavioral changes are discussed.
30 citations
TL;DR: Structural changes were apparent in livers of chickens fed mirex at 10 ppm and above and included regions of necrosis and nonspecific cellular aberrations and alterations of sinusoids and bile canaliculi.
Abstract: Mirex1 was fed in the diet to chickens at 0 to 160 ppm for 12 and 16 weeks, to Japanese quail at 0 to 80 ppm for 12 weeks, and to rats at 0 to 100 ppm for 2 and 4 weeks. Mirex did not affect the concentration of protein or cytochrome P450 in hepatic microsomes of chickens or Japanese quail, nor did it affect hydroxylation of aniline or demethylation of aminopyrine. However, structural changes were apparent in livers of chickens fed mirex at 10 ppm and above and included regions of necrosis and nonspecific cellular aberrations and alterations of sinusoids and bile canaliculi. Mirex caused liver enlargement in rats and increased microsomal protein and cytochrome P450 but did not affect hydroxylation of aniline or demethylation of aminopyrine. Hepatic structural changes in rats that were associated with mirex included proliferation of smooth endoplasmic reticulum and degeneration of some bile canaliculi.
21 citations
TL;DR: The bioassay showed higher residues and slower degradation than chemical analysis, and the correlation between the methods was not established, which could explain this anomalous result.
Abstract: A study of the quantitative analysis of herbicide residues by both chemical and bioassay methods in soils is presented. Field and laboratory residue trials were carried out with a representative member of the following groups of herbicides: ureas, triazines, diphenylethers, phenoxyacetic acids, and dithiophosphates. Representative samples were taken at different time intervals, and degradation curves were established both by chemical methods and by two types of bioassay. Chemical analysis either separated active ingredient and metabolites by chromatographic techniques or comprised total residues. Bioassays were performed using either monocotyledons and dicotyledons or algae. The results obtained by chemical and bioassay analysis for the degradation rates of chlorotoluron, ametryn, 2,4-D and C 19490 showed a correlation coefficient of 0.914, indicating that the two methods gave almost identical results. Especially with the highly adsorbed urea and triazine herbicides, the uptake of biologically active material by test plants was slightly less than the solvent-extractable parent compound plus its metabolites, and so the absolute level of residues obtained by bioassay was lower. In the case of fluorodifen, the correlation between the methods was not established. The bioassay showed higher residues and slower degradation than chemical analysis. Various factors which could explain this anomalous result are discussed.
21 citations
TL;DR: It was shown that all compounds containing carbon atoms, tested in this study, were degraded by the coincident influence of light, oxygen (air), and water, and this photooxidation represents a possibility for pollution control to prevent damage to environment by degrading organic substances which are either slightly soluble or practically insoluble in water.
Abstract: It was shown that all compounds containing carbon atoms, tested in this study, were degraded by the coincident influence of light, oxygen (air), and water. By this photooxidation, saturated as well as unsaturated aliphatic and aromatic compounds, monomeric, polymeric and high polymeric compounds were degraded and the carbon atoms of these compounds as well as carbon itself in form of amorphous carbon or diamond, were converted to carbon dioxide, if dispersed in water or together with water as very small solid, liquid, or gaseous particles. As such conditions occur extensively in nature, it was concluded that this degradation of organic substances is of great importance in nature, in addition to microbial and enzymatic degradation. This photooxidation further represents a possibility for pollution control to prevent damage to environment by degrading organic substances which are either slightly soluble or practically insoluble in water, as well as compounds which will not be destroyed by microbial and enzymatic degradation.
20 citations
TL;DR: Serial observations of DDT-contaminated and uncontaminated salt marshes in the northern Gulf of Mexico were made in November and December, 1973 and it is suggested that the DDT body burdens and reduced temperatures interact to produce acutely toxic effects.
Abstract: Serial observations of DDT-contaminated and uncontaminated salt marshes in the northern Gulf of Mexico were made in November and December, 1973. Blue crab (Callinectes sapidus) mortalities observed in the DDT-contaminated marsh during this period were correlated with reduced daily temperature minima. Gas chromatographic analysis of hepatopancreas and swimmeret muscle tissue of dead and dying crabs revealed total DDT residue concentrations as high as 39.0 ppm and 1.43 ppm, respectively. It is suggested that the DDT body burdens and reduced temperatures interact to produce acutely toxic effects. Several physiological and behavioral mechanisms are proposed.
19 citations
TL;DR: DDT delayed the rate of normal development of fertilized eggs from Fundulus, but did not appear to cause any observable alterations in the hatched fry, and fertilization ofFundulus eggs was significantly diminished when insemination was carried out in DDT-containing sea water.
Abstract: The toxicity, absorption, distribution, metabolism, and effects on reproduction of DDT was studied using the killifish (Fundulus heteroclitus), a species of economic importance because of its widespread abundance and its presence toward the lower end of the food chain. 14C-DDT was administered by exposure from the ambient water. There was a rapid removal of the radioactive pesticide from the water accompanied by uptake of radioactivity primarily by carcass (primarily muscle tissue) and eggs of the fish. Most (greater than 92%) of the radioactivity in the carcass was shown by TLC methods to be the parent pesticide. One day after a single 24-hr exposure to 14C-DDT, approximately 70% of the administered radioactivity was found in the carcass and the levels of the tissue decayed with a t 1/2 of three days. One day after a single 24-hr exposure to 0.1 ppm of 14C-DDT, the organs that contained the highest concentration of the pesticide (ca. 5 ppm) were intestine and liver. When the pesticide was administered by two 24-hr exposures from water, the intestine, liver and ovaries contained the major concentration of radioactivity (7 to 14 ppm). Untreated Fundulus contained less than 0.2 ppm of total DDT-like compounds. A variety of doses and schedules were tested in an effort to maximize the absorption of DDT, while minimizing the mortality to the fish. An intermittent schedule of 24 hr in 0.1 ppm DDT followed by 24 hr in DDT-free sea water, repeated two times, was found to be optimal. At the levels examined, DDT delayed the rate of normal development of fertilized eggs from Fundulus, but did not appear to cause any observable alterations in the hatched fry. Fertilization of Fundulus eggs was significantly diminished when insemination was carried out in DDT-containing sea water.
17 citations
TL;DR: Ethylene is poorly metabolized by Hevea leaves and the evidence available indicates that it is unlikely that any of the compounds produced from I are metabolites of ethylene.
Abstract: Ethephon (I) is used commercially to prolong the flow of latex from the rubber tree after tapping (Yield stimulation). The compound is applied to the bark in the region of the tapping cut and the effect on latex flow is due to the ethylene released by chemical decomposition, since gaseous ethylene itself is also a very effective stimulant. When14C-I is applied to the bark of a youngHevea seedling, it is absorbed into the plant by processes which appear to be largely non-metabolic. Ethylene formation commences immediately at the site of application, and the gas is quickly translocated throughout the plant. Translocation of I to all parts of the plant also occurs and the accumulation of14C in the bark above the zone of application is greater than that below. Chromatographic analysis has shown that compounds other than I remain in the plant tissue.
TL;DR: Oysters demonstrated an ability to significantly concentrate dieldrin and endrin and showed distinct linear regions in semi-logarithmic plots of uptake against time.
Abstract: Oysters demonstrated an ability to significantly concentrate dieldrin and endrin. Concentration ratios obtained after 168-hr exposures to endrin were 1670 at 0.1Μg/L and 2780 at 50Μg/L. Dieldrin was concentrated to higher levels. Exposure to14C-Iabelled dieldrin at 0.5Μg/L produced whole body concentrations 2880 times the ambient level at 168 hr, while exposure to nineΜg/L of dieldrin resulted in a
TL;DR: Individual variability of arsenic uptake did not override trends of greater uptake with increasing exposure time, temperature, and arsenic concentration, but percentage survival decreased and mean arsenic uptake increased slightly as temperature and arsenic concentrations increased.
Abstract: The pattern of arsenic concentration in several tissues ofLepomis cyanellus was measured (by neutron activation analysis) as a function of exposure time at 10‡, 20‡, and 30‡C and 0, 30, 60 ppm of arsenic as sodium arsenate. Individual variability of arsenic uptake did not override trends of greater uptake with increasing exposure time, temperature, and arsenic concentration. The mean temperature coefficient of 4.5 for arsenic uptake in livers was higher than O'Hara's (1968) metabolic figures of 1.6 to 3.0 forLepomis species. The biological half-life of arsenic in liver and gut of live specimens exposed to 30 and 60 ppm of arsenic at 10‡C was about one week. Percentage survival decreased and mean arsenic uptake increased slightly as temperature and arsenic concentration increased.
TL;DR: The concentrations of eight metals were determined by a nondestructive neutron activation technique for eleven species of fish and shellfish collected from ocean dump sites off New York City, off New Haven, Connecticut, and off Delaware Bay.
Abstract: The concentrations of eight metals were determined by a nondestructive neutron activation technique for eleven species of fish and shellfish The marine organisms were collected from ocean dump sites off New York City, off New Haven, Connecticut, and off Delaware Bay Antimony was not detected in most of the organisms examined in thid study; the detection limit was about 002 to 005 ppm Antimony levels ranged from 001 to 0129 ppm in fish that had detectable levels Cobalt levels were low in all samples with most levels in the range of 01 to 03 ppm Chromium concentrations at 03 to 10 ppm were only roughly quantitated by the procedure employed Most marine organisms examined had chromium levels at or below these values Nickel was not detected in any of the organisms examined; the detection limit was in the 3 to 6 ppm range Rubidium concentrations were 06 to 15 ppm for most organisms; only rough quantitative measurement was possible at these levels Selenium levels ranged from about 03 to 38 ppm in all samples Silver concentrations were below 03 ppm in most organisms Silver concentrations as high as 10 to 30 ppm, however, were found in the digestive gland of rock crab Zinc levels in windowpane flounder liver were about 6 to 9 times greater than the 4 to 10 ppm levels found in muscle Zinc concentrations in rock crab muscle, on the other hand, were only slightly higher than the 15 to 32 ppm concentration found in the digestive gland Fish other than windowpane flounder had zinc levels that ranged from 4 to 9 ppm in the muscle and 14 to 42 ppm in the liver Shellfish other than rock crab had zinc levels of 15 to 30 ppm in muscle and 17 to 40 ppm in the digestive gland
TL;DR: Houseflies in cages near the ceiling, exposed to an insecticide, and forcedAir movement, exhibited greater mortality than those in cages on the floor, while the reverse was true for houseflies in rooms with no forced air movement.
Abstract: The movement of chlorpyrifos and diazinon from cracks and crevices in empty dormitory rooms with and without forced air movement to houseflies and plates in non-target areas was studied. Aluminum pie plates in rooms with the high concentrations of an insecticide, no forced air movement, and at the earlier sampling interals contained more insecticide. Insecticides were not detectable at 48 hr. Increased housefly movement occurred simultaneously with the initiation of insecticide application in rooms with forced air and 1 min later in rooms with no forced air. Mortality of houseflies exposed during and at 5 hr after insecticide application was greater for males than females in all tests except one; at the high insecticide concentrations; and at successive time intervals through the 24-hr interval after their transfer from the treated rooms to holding rooms. Houseflies in cages near the ceiling, exposed to an insecticide, and forced air movement, exhibited greater mortality than those in cages on the floor, while the reverse was true for houseflies in rooms with no forced air movement.
TL;DR: Its low persistence and low animal toxicity suggest that triforine does not offer serious hazards to the environment.
Abstract: After short-term root-treatment of plants with3H-triforine (labelled in the piperazine ring) or14C-triforine (labelled in the side chain), the label was translocated primarily to the leaves present at the time of treatment, without any redistribution of the label taking place after termination of the treatment. Autoradiography showed the radioactivity to be very evenly distributed over the leaf blades, without any appreciable accumulation in leaf margins. In infected leaves, however, there was a tendency for increased accumulation at the infection sites. In dilute aqueous solution triforine was decomposed rather rapidly, the chemical half-life being three days only. From these solutions several non-fungitoxic degradation products have been isolated and their chemical structures determined. In plants, decomposition of triforine was considerably slower than in aqueous solutions, the half-life of the compound varying depending on plant species. In plants, at least four conversion products could be demonstrated, one of which is piperazine. Whether the other three compounds are identical with or structurally related to the breakdown products found in aqueous solution is not yet known. Its low persistence and low animal toxicity suggest that triforine does not offer serious hazards to the environment.
TL;DR: It was concluded that the disappearance of the herbicide from non-sterile soils was mainly due to microbial degradation and to binding of diallate or its metabolites as residues to undefined soil components.
Abstract: The disappearance of the herbicide, Avadex (40% diallate), from five agricultural soils (differing in either pH, carbon content, or nitrogen content), incubated under sterile and non-sterile conditions, was followed for a period of 20 weeks. Avadex was rapidly lost from microbiologically active soils, with over 50% of the applied (2.5 ppm) dosage disappearing within four weeks; losses from sterile soils were much slower with recoveries of over 50% after 20 weeks. Incubation of soil with Avadex to which14C-labeled diallate had been added resulted in rapid formation of14CO2 from microbiologically active samples and only very slow14CO2 formation from sterile samples. Substantial quantities of radioactivity were retained as unextractable residues in both sterile and non-sterile soils after seven days incubation. From these data it was concluded that the disappearance of the herbicide from non-sterile soils was mainly due to microbial degradation and to binding of diallate or its metabolites as residues to undefined soil components. Losses from sterile soils were attributed to both binding of residues and to a slow chemical degradation. Avadex degradation by pure cultures was studied using representative fungi isolated from the five soils. Of the fungi tested,Phoma eupyrena, Penicillium janthinellum, andTrichoderma harzianium could degrade at least 20% of the applied (2.5 ppm) herbicide after ten days incubation. Degradation of Avadex in soil cultures ofT. harzianum was found to be slower than degradation in liquid nutrient cultures.
TL;DR: In this article, young growing lambs and pigs were fed a ration containing 200 ppm of Aroclor 1254 for 35 days and then switched to clean feed, and blood and fat samples were collected periodically throughout the experiment.
Abstract: Young growing lambs and pigs were fed a ration containing 200 ppm of Aroclor 1254 for 35 days and then switched to “clean” feed. Blood and fat samples were collected periodically throughout the experiment and analyzed for components of Aroclor 1254 and total PCB. Several components are apparently accumulated and eliminated at different rates within each species, as seen by comparing gas chromatograph tracings, accumulation ratios and apparent rate constants of elimination.
TL;DR: It is demonstrated that mirex can be leached from bait by fresh water and concentrated by and affect survival of members in an experimental estuarine community.
Abstract: Experimental communities of various estuarine animals in outdoor tanks were exposed to a continuous flow of water containing mirex for 10 weeks. The mirex was leached from fire ant bait (0.3% active ingredient) by fresh water which was then mixed with salt water to yield exposure concentrations averaging 0.038Μg/L. The experiment simulated runoff from treated land into estuarine areas. Mortality of grass shrimp (Palaemonetes vulgaris), pink shrimp (Penaeus duorarum), common mud crabs (Panopeus herbstii), and striped hermit crabs (Clibanarius vittatus) was significantly higher in tanks containing the toxicant. Mortality of ribbed mussels (Modiolus demissus) and American oysters (Crassostrea virginica) was significantly lower in treated tanks, probably because numbers of both species of crabs, which ate the bivalves, were reduced. Sheepshead minnows (Cyprinodon variegatus) were least affected by mirex. Almost all deaths occurred after 10 or more days of exposure. All exposed animals accumulated mirex, with maximum concentrations ranging from 5,500X (pink shrimp) to 73,700X (soft tissues of oysters) above the concentration in the water. Sand substratum contained mirex up to 1,500X that in the water. The study demonstrated that mirex can be leached from bait by fresh water and concentrated by and affect survival of members in an experimental estuarine community.
TL;DR: Eastern oysters (Crassostrea virginica) were found to accumulate significant levels of mercury on exposure to relatively low concentrations of mercuric chloride, and accumulation occurred in two distinct phases which may be described as a two compartment system.
Abstract: Eastern oysters (Crassostrea virginica) were found to accumulate significant levels of mercury on exposure to relatively low concentrations of mercuric chloride. Accumulation occurred in two distinct phases which may be described as a two compartment system in which accumulation is logarithmic in the first phase and linear in the second. Mercury, during the initial phase, showed a minimum outward concentration flux of 0.025 hr−1 indicating reversibility of accumulation prior to the change in phase. However, mercury was not excreted at the end of the second phase following exposure to 10, 40, 80, and 100Μg/1 for 256 hr.
TL;DR: Relationships and low Zn/Cd ratios in surface horizons nearest to the smelter indicated surface deposition of airborne smelters emissions was responsible for metal contamination of Trail area surface soils.
Abstract: The distribution of cadmium, lead and zinc concentrations in litter and mineral soil horizons from the Kootenay region were studied to determine the effect of the 70-yr operation of the world's largest base-metals smelter complex at Trail, British Columbia. Metals were retained near the surface in litter and surface mineral horizons and concentrations in deepest horizons were lower and normal for uncontaminated soils. Metal concentrations in surface horizons were significantly related to distance from the smelter and site elevation in the mountainous region. Regression equation models to predict metal concentrations as functions of distance and/or elevation accounted for 69.8, 93.3 and 76.7% of variance in litter concentrations of Cd, Pb, and Zn, respectively, and 91.3, 50.6, and 64.0% of their variances in surface mineral horizons. In view of concomitant random distribution of metal concentrations in deepest horizons, these relationships and low Zn/Cd ratios in surface horizons nearest to the smelter indicated surface deposition of airborne smelter emissions was responsible for metal contamination of Trail area surface soils.
TL;DR: Rain appeared to have markedly reduced dislodgable residues in tobacco fields treated with monocrotophos, and experiments with mice were in general agreement with the human tests.
Abstract: Thirteen to fifteen human volunteers worked for eight-hr periods in tobacco fields treated 96, 72, and 48 hr previously with monocrotophos (3-hydroxy-N-methyl-cis-crotonamide dimethyl phosphate). At the 48-hr reentry period, during which time no rainfall occurred, both post-exposure plasma and red blood cell cholinesterase levels of the worker group were depressed from pre-exposure levels although the decline was less than 9% in both cases. Rainfall in excess of one inch fell during the 96- and 72-hr reentry intervals, and no important change in cholinesterase levels was noted. Experiments with mice were in general agreement with the human tests. Dimethyl phosphoric acid in urine of the worker group collected prior to, and three hr after, exposure was unchanged in all cases. Rain appeared to have markedly reduced dislodgable residues.
TL;DR: Foliar additions of labeled herbicides and growth regulators generally showed only minor absorption and translocation within the leaf and weathering processes and volatility during a 6- to 12-week period left variable amounts of residue, characteristic of individual compounds, adsorbed at the treated sites.
Abstract: Absorption of 14C-labeled herbicides from nutrient culture solution through the roots of sugarcane plants (Saccharum spp. hybrids) resulted in three major types of distribution. Labeled residues from atrazine, ametryne, and metribuzine moved easily through the xylem to the green leaves and were deposited mainly at the leaf margins and tip. Senescence and leaf abscission removed most of the deposit from the plant. Picloram translocated rapidly into the leaves, but appeared to recycle from older to younger leaves with only small portions remaining in the senescent leaves. Asulam and pentachlorophenol (PCP) were absorbed by the roots; residues did not pass into the xylem and remained fixed in the roots. Foliar additions of labeled herbicides and growth regulators generally showed only minor absorption and translocation within the leaf. Weathering processes and volatility during a 6- to 12-week period left variable amounts of residue, characteristic of individual compounds, absorbed at the treated sites.
TL;DR: The herbicide oxadiazon, 2-(tert-butyl)-4-(2,4-dichloro-5-isopropyloxy-phenyl)-δ2-1, 3, 4-oxadiazoline 5-one, was fed in a total diet at three dosage levels to groups of dairy cows and groups of male and laying female quail for 28 days.
Abstract: The herbicide oxadiazon, 2-(tert-butyl)-4-(2,4-dichloro-5-isopropyloxy-phenyl)-δ2-1, 3, 4-oxadiazoline 5-one, was fed in a total diet at three dosage levels to groups of dairy cows (0.5, 2.5, and 25 ppm) and to groups of male and laying female quail (20, 80, and 160 ppm) for 28 days. Control animals received basal diet rations. No residue (<5 ppb) was detected in milk or cream after three days withdrawal from fortified feed. The maximum plateau reached in milk was 83.8 ppb at the highest dosage fed. Tissues of cows sacrificed on the 12th day of withdrawal showed no residue (<20 ppb). Birds were sacrificed at weekly intervals during acclimation, intake, and withdrawal periods. Eggs were collected at the same intervals. Tissues were free of oxadiazon residue (<40 ppb) within two to seven days of returning the quail to the basal ration, and the eggs were residue-free within seven to fourteen days. The maximum residue found in adipose tissue of quail and their fresh eggs was 3100 ppb and 5400 ppb, respectively at the greatly exaggerated dosage of 160 ppm in the diet. A comprehensive analytical methodology, including liquid-liquid partition, absorption chomatography and electron-capture gas chromatography will be discussed.
TL;DR: Higher harvest-time parathion residues on and in the fruit resulted when the first two formulations were used, and the time needed to reach a tolerance value increased for applications made later in the growing season.
Abstract: The fate of parathion applied to citrus was affected by rain, sun and wind, but not much by fruit variety, while the application method had an important effect. The formulation influenced the persistence of parathion on leaves and glass in the laboratory, but had no influence on the persistence on leaves or fruit in the field. The deposits of the emulsifiable concentrate and of the wettable powder and oil mixture were higher than that of the wettable powder alone, but since the rates of disappearance were the same, higher harvest-time parathion residues on and in the fruit resulted when the first two formulations were used. The time needed to reach a tolerance value increased for applications made later in the growing season.
TL;DR: The results suggest that the acute toxic effects of DDT are species-dependent and the administration route is important in DDT toxicity.
Abstract: DDT was administered to the guinea pig, mouse and rat either ig or ip and to the hamster ig in order to investigate variations in the response of hepatic and duodenal drug-metabolizing enzymes to DDT. The intragastric dose (160 mg/kg) was found to produce gastric bleeding and severe tremor in rats and mice but not in other rodents. The hepatic aryl hydrocarbon hydroxylase activity and cytochrome P-450 concentration decreased after the ig administration of DDT to rats, mice and guinea pigs but in hamsters the activity of aryl hydrocarbon hydroxylase and cytochrome P-450 concentration increased 12 hr after the dosage. The aryl hydrocarbon hydroxylase activity decreased also in the duodenal mucosa of the rat after the ig administration of DDT. The ip dose had no effects on the hepatic or duodenal monooxygenase system in 12 hr. The UDPglucuronosyltransferase activity was slightly lowered in hepatic microsomes of the rat and mouse after the ig dose of DDT, but the decrease was more profound when measured afterin vitro trypsin digestion of microsomes. The trypsin digestion activated the hepatic UDPglucuronosyltransferase in all the species studied,i.e., guinea pig, hamster, mouse and rat (3-, 3-, 5-, and 8-fold, respectively). The duodenal UDPglucuronosyltransferase activity was not affected by DDT administration in any of the species studied. The results suggest that the acute toxic effects of DDT are species-dependent and the administration route is important in DDT toxicity. The hydroxylation step in drug metabolism is more sensitive to DDT than the glucuronidation step.
TL;DR: The cholesterol derivative may represent a new “detoxification mechanism” in plants; the epiperoxide may help to elucidate plant oxidation mechanisms.
Abstract: Carbaryl (1-naphthyl methylcarbamate), labeled with14C in the C1-naphthyl, carbonyl, orN-methyl position, was introduced into the culture medium of tobacco cells in suspension culture. Following incubation, cells were homogenized in water, centrifuged, and supernatants hydrolyzed withΒ-glucosidase or HCl. Organic moieties (moieties) were characterized by two-dimensional thin-layer chromatography (TLC), and many were subsequently identified by infrared and mass spectrometry. On the basis of the data obtained with14C1-naphthyl-labeled carbaryl, it appeared that 18.4% of the total characterized metabolites represented unconjugatedN-CH2OH- carbaryl [1-naphthylN-(hydroxymethyl)carbamate], excreted by the cells into the culture medium. The metabolites found in the cells primarily consisted of conjugates of 1-naphthol (73.6% of the total characterized metabolites) andN-CH2OH-carbaryl (2.5%). Conjugates of 7-hydroxycarbaryl (7-hydroxy-1-naphthyl methylcarbamate), 4-hydroxycarbaryl (4-hydroxy-1-naphthyl methylcarbamate), and 5-hydroxycarbaryl (5-hydroxy-1-naphthyl methylcarbamate) were also detected in small amounts. Of five unknown14C1-naphthyl-labeled carbaryl metabolites, three were tentatively characterized as:O-1-naphthylcholesterol (cholest-5-en-3Β-yl-1-naphthol; 3.0%); an unconjugated hydroxylated 1,4-dihydro-1,4-epiperoxynaphthalene (1.4%); and an acidlabile,Β-glucosidase-resistant conjugate of acis-dihydrodiol of 1-naphthol (0.3%; other than thetrans-5,6-dihydrodiol). The cholesterol derivative may represent a new “detoxification mechanism” in plants; the epiperoxide may help to elucidate plant oxidation mechanisms. A new TLC procedure was developed which successfully separated the acetate derivative ofN-hydroxycarbaryl (1-naphthylN-hydroxy-N-methylcarbamate) from 12 other common moieties of carbaryl metabolites and their acetate derivatives. A new two-dimensional TLC system was developed for the separation of underivatizedN-hydroxycarbaryl from 14 other moieties of carbaryl metabolites; two additional two-dimensional TLC systems were utilized for moiety separations. With these TLC procedures, no conjugated or unconjugatedN-hydroxycarbaryl could be detected in any tobacco cell culture fraction after incubation of cells in medium containing radiolabeled carbaryl. Authentic14C1-naphthyllabeledN-CH2OH-carbaryl was shown to be converted to desmethylcarbaryl (1-naphthylcarbamate) (97%) and 1-naphthol (3%) by 0.1N HCl hydrolysis.
TL;DR: In this article, the metabolism and rate of penetration of leptophos (O-methylO-4bromo-2,5-dichlorophenyl phenylphosphonothioate) was determined in a susceptible strain and a strain of houseflies which was 50-fold resistant to leptonophos.
Abstract: The metabolism and rate of penetration of leptophos (O-methylO-4-bromo-2,5-dichlorophenyl phenylphosphonothioate) was determined in a susceptible strain and a strain of houseflies which was 50-fold resistant to leptophos. Penetration of leptophos into resistant flies was substantially slower than into susceptible flies but large differences in metabolism, both quantitatively and qualitatively, were not observed. No difference was observed in the sensitivity of flyhead and thorax acetylcholinesterase to leptophos-oxonin vitro, and tolerance to leptophos by the resistant strain is explained in terms of decreased rates of penetration and minor differences in metabolism.
TL;DR: A mathematical model simulating the blood transport and tissue residue distributions of the highly toxic and highly lipid soluble pesticide dieldrin in mammals is presented and is a significant improvement over the previously published preliminary model.
Abstract: A mathematical model simulating the blood transport and tissue residue distributions of the highly toxic and highly lipid soluble pesticide dieldrin in mammals is presented. This model is a significant improvement over our previously published preliminary model for dieldrin distribution in mammals. The assumptions and working hypotheses of the model are presented and used in generating a set of differential equations based upon mass balance principles. Two simulation cases are examined. The first simply demonstrates the gross features of: 1) Transport limiting conditions; 2) equal transport-equal membrane transfer conditions, and 3) membrane transfer limit conditions. The second studies a single tissue (the blood-brain barrier case) example of the above mentioned conditions. All simulations made were conducted for a hypothetical mature male rate of the average Wistar® type eating foodad lib.
TL;DR: It was concluded that the selective activity of 1,1-Dimethyl-3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(I) between barley and wheat plants was mainly due to the difference in rates of N-demethylation.
Abstract: 1,1-Dimethyl-3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(I) was newly synthesized by the authors. (I) was found to have the strongest herbicidal activities among the thiadiazolylurea derivatives and selectivity of (I) was found between barley (tolerant) and wheat (susceptible) plants. Neither absorption by roots nor translocation from roots to shoots of35S-labeled (I) in barley and wheat correlated with selectivity between these species of plants. (I) was metabolized in both species of plants byN-demethylation to 1-methyl-3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(II), and further to non-phytotoxic 3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(III).