RESUMEN
Organochlorine pesticides and PCB (POPs) concentrations were determined in the blood and eggs of green and hawksbill turtles. We compared concentrations between species, analyzed the relationship between turtle size and the POPs concentrations and the relationship between the concentrations in the blood of the nesting turtles and their eggs. We expected higher concentrations in the hawksbill turtle because of its higher trophic level, but concentrations were not higher in all the cases. Significant differences were found in δ-HCH blood concentrations. Lindane, heptachlor epoxide and PCB 101 concentrations were significantly higher in the hawksbill eggs. The relationship between the size of the turtles and the POP concentrations in the eggs of the hawksbills showed a negative correlation. No correlation was found between the size of the female and concentrations in the blood. In eggs, only the hawksbill turtles exhibited negative correlation in the concentration of mirex and PCB 44 and size.
Asunto(s)
Hidrocarburos Clorados/sangre , Exposición Materna , Óvulo/metabolismo , Plaguicidas/sangre , Bifenilos Policlorados/sangre , Tortugas/sangre , Animales , Femenino , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/sangre , Hexaclorociclohexano/metabolismo , Hidrocarburos Clorados/metabolismo , México , Plaguicidas/metabolismo , Bifenilos Policlorados/metabolismo , Especificidad de la Especie , Estadísticas no Paramétricas , Tortugas/metabolismoRESUMEN
The ability of certain white-rot fungi (WRF) inocula to transform heptachlor and heptachlor epoxide and its application in artificially contaminated soil were investigated. Fungal inoculum of Pleurotus ostreatus eliminated approximately 89 % of heptachlor after 28 days of incubation, and chlordene was detected as the primary metabolite. The fungal inoculum of Pleurotus ostreatus had the highest ability to degrade heptachlor epoxide; approximately 32 % were degraded after 28 days of incubation, and heptachlor diol was detected as the metabolite product. Because Pleurotus ostreatus transformed heptachlor into a less toxic metabolite and could also effectively degrade heptachlor epoxide, it was then selected to be applied to artificially contaminated soil. The spent mushroom waste (SMW) of Pleurotus ostreatus degraded heptachlor and heptachlor epoxide by approximately 91 and 26 %, respectively, over 28 days. This finding indicated that Pleurotus ostreatus SMW could be used to bioremediate heptachlor- and heptachlor epoxide-contaminated environments.
Asunto(s)
Epóxido de Heptaclor/metabolismo , Heptacloro/metabolismo , Insecticidas/metabolismo , Pleurotus/metabolismo , Contaminantes del Suelo/metabolismo , Biodegradación AmbientalRESUMEN
White rot fungi of the genus Phlebia have demonstrated a high capacity to degrade organic pollutants, including polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls. In this study, we evaluated the ability of 18 white rot fungi species of genus Phlebia to degrade heptachlor and heptachlor epoxide, and described the metabolic pathways by selected white rot fungi. Phlebia tremellosa, Phlebia brevispora and Phlebia acanthocystis removed about 71%, 74% and 90% of heptachlor, respectively, after 14 days of incubation. A large amount of heptachlor epoxide and a small amount of 1-hydroxychlordene and 1-hydroxy-2,3-epoxychlordene were detected as metabolic products of heptachlor from most fungal cultures. The screening of heptachlor epoxide-degrading fungi revealed that several fungi are capable of degrading heptachlor epoxide, which is a recalcitrant metabolite of heptachlor. Phlebia acanthocystis, P. brevispora, Phlebia lindtneri and Phlebia aurea removed about 16%, 16%, 22% and 25% of heptachlor epoxide, respectively, after 14 days of incubation. Heptachlor diol and 1-hydroxy-2,3-epoxychlordene were produced in these fungal cultures as metabolites, suggesting that the hydrolysis and hydroxylation reaction occur in the epoxide ring and in position 1 of heptachlor epoxide, respectively.
Asunto(s)
Basidiomycota/metabolismo , Epóxido de Heptaclor/metabolismo , Heptacloro/metabolismo , Plaguicidas/metabolismo , Biotransformación , Indenos/metabolismo , Factores de TiempoRESUMEN
Organochlorine pollutants in the major fish species (pike Esox lucius, perch Perca fluviatilis, and roach Rutilus rutilus) of Lake Arungen, Norway, were investigated after an extensive removal of large pike in 2004. The organochlorine pollutants detected in fish liver samples in 2005 were dichlorodiphenyltrichloroethane (DDTs), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and heptachlor epoxide (HCE). DDTs were the dominant among all analyzed OCs. Sigma PCB and HCB, detected in fish from two clearly distinct trophic levels (prey and predators), give an indication of biomagnification. All OC concentrations in female pike were significantly lower compared to males, which might be due to the removal of high concentrations of pollutants in roe during spawning.
Asunto(s)
Peces/metabolismo , Hidrocarburos Clorados/metabolismo , Lagos , Contaminantes Químicos del Agua/metabolismo , Animales , Cyprinidae/metabolismo , DDT/metabolismo , Ecosistema , Monitoreo del Ambiente , Esocidae/metabolismo , Cadena Alimentaria , Epóxido de Heptaclor/metabolismo , Hexaclorobenceno/metabolismo , Noruega , Percas/metabolismo , Bifenilos Policlorados/metabolismoRESUMEN
Degradation of aldrin (1,2,3,4,10,10-Hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5-8-dimethanonaphthalene), heptachlor (1H-1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano indene), dieldrin (1aalpha,2beta,2aalpha,3beta,6beta,6aalpha,7beta,7aalpha)-3,4,5,6,9,9-Hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-d-methanonaphtha[2,3-b]oxirene, and heptachlor epoxide (1aalpha, 1bbeta,2alpha,5alpha,5alphabeta,6beta,6aalpha-2,3,4,5,6,7,7-Heptachloro-1a,1b,5,5a,6,6a-hexahydro-2,5-methano-2H-inden[1,2-b]-oxirene) was tested using free cultures of Pseudomonas fluorescens under controlled conditions. Pesticide concentrations were monitored by gas chromatography during 120 h. Percentages of degradation and biodegradation rates (BDR) were calculated. Data showed a trend suggesting a relation between chemical structure and degradability. Degradation kinetics for each pesticide tested showed that the highest degradation rates were found in the first 24 h. Kinetics data were adjusted to an empirical equation in order to predict their behavior, and the correlation coefficients obtained were satisfactory. Gas chromatography/mass spectrometry (GC/MS) analysis of the final extracts allowed the identification of chlordene and monodechlorodieldrin, which have been reported as final metabolite produced in the biodegradation of this kind of compounds. Regarding adsorption of pesticides on activated vegetal carbon, we concluded that removal efficiencies between 95.45 and 97.18% can be reached, depending on the pesticide and the carbon dose applied. The values for K from the Freundlich equation were quite similar for the four pesticides (between 1.0001 and 1.04), whereas the n values were quite different for each pesticide in the following order of affinity: dieldrin > aldrin > heptachlor epoxide > heptachlor. Equilibrium times, very important for scaling up the process, were between 43 min and 1 h, for the heptachlor epoxide and the heptachlor, respectively.
Asunto(s)
Carbón Orgánico/química , Insecticidas/química , Insecticidas/metabolismo , Pseudomonas fluorescens/metabolismo , Adsorción , Aldrín/análisis , Aldrín/química , Aldrín/metabolismo , Biodegradación Ambiental , Cromatografía de Gases , Dieldrín/análisis , Dieldrín/química , Dieldrín/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Heptacloro/análisis , Heptacloro/química , Heptacloro/metabolismo , Epóxido de Heptaclor/análisis , Epóxido de Heptaclor/química , Epóxido de Heptaclor/metabolismo , Insecticidas/análisis , Cinética , Microbiología del Suelo , Contaminantes del Suelo/análisisRESUMEN
This study was performed to determine if developmental exposure of rats to heptachlor (H) during the last half of gestation through puberty adversely affects adult functioning of the immune and reproductive systems. Time-bred pregnant female Sprague-Dawley rats were dosed by gavage with H (0, 30, 300, or 3000 microg/kg/day) from gestation day (GD) 12 to postnatal day (PND) 7, followed by direct dosing of the pups with H through PND 42. Separate groups of rats were evaluated with a battery of immune function tests, while other groups of rats were evaluated for reproductive development and function. Additional groups of rats were euthanized at the end of the dosing period for histological analyses of major organ systems. Some dams and PND 7 pups were euthanized; milk, plasma, fat and/or tissues were assayed for H and heptachlor epoxide B (HEB), a major metabolite of H. The amount of H and HEB found in milk, blood, fat, and tissues was proportional to the dose of H administered. There were no effects on the number or survival of pups born to H-exposed dams nor to pups exposed postnatally. There were no effects on the number of treated dams delivering litters or on litter size, nor were there any effects on any of the reproductive end points examined in the F(0) or F(1) rats. There were no effects of H exposure on lymphoid organ weights, splenic natural killer (NK) cell activity, and splenic lymphoproliferative (LP) responses to mitogens and allogeneic cells in a mixed lymphocyte response (MLR) assay at 8 weeks of age. H exposure did not alter delayed or contact hypersensitivity at 10 or 17 weeks of age, respectively. However, the primary IgM antibody response to sheep red blood cells (SRBCs) was suppressed in a dose-dependent manner in males, but not females, at 8 weeks of age. The percentage of B lymphocytes (OX12(+)OX19(-)) in spleen was also reduced in the high-dose males. The anti-SRBC IgM response was reduced only in males exposed to 30 microg H/kg/day in a separate group of rats 21 weeks of age. In these same rats, at 26 weeks of age, the secondary IgG antibody response to SRBCs was suppressed in all of the H-exposed males, but not females. These data indicate that perinatal exposure of male rats to H results in suppression of the primary IgM and secondary IgG anti-SRBC responses. Suppression of these antibody responses persisted for up to 20 weeks after the last exposure to H, at a total exposure of approximately 1500 microg H/kg/rat.
Asunto(s)
Heptacloro/toxicidad , Sistema Inmunológico/efectos de los fármacos , Exposición Materna/efectos adversos , Efectos Tardíos de la Exposición Prenatal , Reproducción/efectos de los fármacos , Maduración Sexual/efectos de los fármacos , Animales , Animales Recién Nacidos , Formación de Anticuerpos/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Edad Gestacional , Heptacloro/administración & dosificación , Heptacloro/análisis , Heptacloro/metabolismo , Epóxido de Heptaclor/análisis , Epóxido de Heptaclor/metabolismo , Epóxido de Heptaclor/toxicidad , Hipersensibilidad Tardía/inducido químicamente , Inmunoglobulina G/análisis , Inmunoglobulina G/sangre , Inmunoglobulina M/análisis , Inmunoglobulina M/sangre , Insecticidas/toxicidad , Células Asesinas Naturales/efectos de los fármacos , Tamaño de la Camada , Masculino , Tamaño de los Órganos/efectos de los fármacos , Linaje , Embarazo , Ratas , Ratas Sprague-Dawley , Bazo/efectos de los fármacos , Subgrupos de Linfocitos T/efectos de los fármacos , Distribución TisularAsunto(s)
Tejido Adiposo/metabolismo , Clordano/análogos & derivados , Clordano/toxicidad , Epóxido de Heptaclor/toxicidad , Insecticidas/toxicidad , Tejido Adiposo/efectos de los fármacos , Contaminación del Aire Interior , Animales , Clordano/administración & dosificación , Clordano/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Cromatografía de Gases y Espectrometría de Masas , Epóxido de Heptaclor/administración & dosificación , Epóxido de Heptaclor/metabolismo , Insecticidas/administración & dosificación , Insecticidas/metabolismo , Japón , Ratones , EstereoisomerismoRESUMEN
Organochlorine pesticide levels were determined in Neotropical migrant passerines which have populations reported to be declining. Pesticide residues ranging from 0.385 to 27.4 ng/g were found in 19 of 21 birds, including both Hatch Year (HY) and After Hatch Year (AHY) age classes of nine different species. Eighteen of the 19 birds contained p,p'-DDE, while dieldrin was found in 16 birds and heptachlor epoxide was present in 10 birds. There were no significant differences in pesticide levels between HY and AHY birds, suggesting that HY birds are exposed to pesticides in their diet on the breeding ground or that pesticides are acquired from contaminated mothers, or both. Pesticide levels were not related to gender. Although the effects of these low residue levels on passerine fecundity are unknown, their presence has potential conservation implications for passerines and for the raptorial birds that feed upon them.
Asunto(s)
Diclorodifenil Dicloroetileno/metabolismo , Epóxido de Heptaclor/metabolismo , Insecticidas/análisis , Residuos de Plaguicidas/metabolismo , Animales , Aves , Femenino , Insecticidas/metabolismo , Masculino , Factores Sexuales , Programas Informáticos , Especificidad de la Especie , Distribución TisularRESUMEN
Six U.S. Food and Drug Administration laboratories participated in an Interlaboratory trial of a solid-phase extraction cleanup method for determination of pesticides in nonfatty seafood products. The participants analyzed control and fortified (about 0.050 ppm lindane, heptachlor epoxide, p,p'-DDE, and endrin) croaker and flounder samples and a sea trout sample containing incurred p,p'-DDE residues. Mean recoveries of the fortified residues from the fish ranged from 89.1 to 107.8%. The within-laboratory coefficients of variation (CVs) ranged from 4.2 to 8.5%, and the among-laboratory CVs ranged from 10.9 to 26.5%. The 6 laboratories reported a mean value of 0.040 ppm p,p'-DDE in a fish sample which contained incurred residues. The same value (0.040 ppm) was obtained by using official methodology. The within-laboratory CVs ranged from 3.5 to 18.3%, and the among-laboratory CV was 17.3%.
Asunto(s)
Peces/metabolismo , Contaminación de Alimentos/análisis , Insecticidas/análisis , Residuos de Plaguicidas/análisis , Análisis de Varianza , Animales , Cromatografía de Gases , Diclorodifenil Dicloroetileno/análisis , Diclorodifenil Dicloroetileno/metabolismo , Endrín/análisis , Endrín/metabolismo , Análisis de los Alimentos , Epóxido de Heptaclor/análisis , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/análisis , Hexaclorociclohexano/metabolismo , Insecticidas/metabolismo , Reproducibilidad de los Resultados , Estereoisomerismo , Estados Unidos , United States Food and Drug AdministrationRESUMEN
This monitoring study of 192 samples of cow's milk collected from the central region of Veracruz state was conducted to determine the contamination levels of organochlorine pesticides. The results obtained for mean DDT and HCH levels were 0.057 and 0.098 mg/kg respectively expressed on fat basis and are within FAO tolerances and similar to those found in other tropical countries.
Asunto(s)
Insecticidas/análisis , Leche/química , Residuos de Plaguicidas/análisis , Aldrín/análisis , Aldrín/metabolismo , Animales , Bovinos , Cromatografía de Gases , DDT/análisis , DDT/metabolismo , Diclorodifenil Dicloroetileno/análisis , Diclorodifenil Dicloroetileno/metabolismo , Análisis de los Alimentos , Contaminación de Alimentos , Guías como Asunto , Heptacloro/análisis , Heptacloro/metabolismo , Epóxido de Heptaclor/análisis , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/análisis , Hexaclorociclohexano/metabolismo , Insecticidas/metabolismo , México , Residuos de Plaguicidas/metabolismo , Organización Mundial de la SaludRESUMEN
Remarkably high concentrations of alpha-hexachlorocyclohexane (alpha-HCH), cis-heptachlorepoxide and oxychlordane were found in roe-deer liver samples both from the northern and southern German states Schleswig-Holstein and Baden-Württemberg, respectively. The data revealed no significant regional differences, but they showed some common characteristics: a preferential degradation of (+)-alpha-HCH, and a preferential enrichment of (+)-oxychlordane and of (+)-cis-heptachlorepoxide as determined by chiral capillary gas chromatography using modified cyclodextrin phases. Calculation of the spearman rank correlation coefficients rS supported the assumption that higher concentrations of alpha-HCH may result in a stronger decomposition of the (+)-enantiomer, while higher levels of cis-heptachlorepoxide and oxychlordane appear to lead to a faster decomposition of the respective (-)-enantiomer or a preferential formation of the respective (+)-enantiomer.
Asunto(s)
Clordano/análogos & derivados , Ciervos , Epóxido de Heptaclor/análisis , Hexaclorociclohexano/análisis , Hígado/química , Animales , Biodegradación Ambiental , Clordano/análisis , Clordano/metabolismo , Alemania , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/metabolismo , Hígado/metabolismo , EstereoisomerismoRESUMEN
Field trials were conducted to measure translocation of pesticides by summer and winter forage/pasture species from soil containing aged residues of heptachlor and, to a lesser extent, dieldrin. Substantial amounts of heptachlor epoxide, and lesser amounts of gamma-chlordane were translocated to plants from contaminated soil. Residue levels varied with crop species and stage of plant development. In summer crops residues were higher in soybean > cowpeas > lab-lab > Sorghum > millet > sweet saccaline at the grazing and mature stages. Compared to glasshouse studies undertaken previously, residues in crops grown under field conditions were much lower. This apparently reflects the lower soil moisture levels and the reduced rates of translocation. Heptachlor residues in winter crops were highest in Saia oats > Berseem clover > Haifa clover > Cassia oats > Tetila ryegrass > Schooner barley > Shaftal clover > Hunter river lucerne at the grazing stage. There were no detectable levels in barley and oats at the mature stage. No dieldrin residues were translocated into the various crop species.
Asunto(s)
Animales Domésticos , Insecticidas/metabolismo , Residuos de Plaguicidas/metabolismo , Plantas/metabolismo , Contaminantes del Suelo/metabolismo , Alimentación Animal , Animales , Clordano/metabolismo , Dieldrín/metabolismo , Grano Comestible/crecimiento & desarrollo , Grano Comestible/metabolismo , Fabaceae/crecimiento & desarrollo , Fabaceae/metabolismo , Contaminación de Alimentos , Heptacloro/metabolismo , Epóxido de Heptaclor/metabolismo , Desarrollo de la Planta , Plantas Medicinales , Poaceae/crecimiento & desarrollo , Poaceae/metabolismoRESUMEN
The changes in concentration of heptachlor epoxide (HCE) and oxychlordane (OCD) were studied in the tissues of beef cattle that had previously grazed pasture contaminated with commercial heptachlor. In 25 cows and heifers monitored over 488 days, the mean concentration of HCE decreased from 22.0 to 0.08 mg/kg and of OCD from 5.68 to 0.18 mg/kg. The respective half-lives were estimated to be 66 and 92 days. In a controlled feeding experiment, nine steers were subjected to one of three dietary regimes; a high plane of nutrition for 81 days then a low plane for 140 days; a moderate plane of nutrition for the total period; and a low plane of nutrition for 81 days then a high plane for 140 days. Approximately five months later similar treatments were applied for 101 and 94 days. The rate of decline of HCE and OCD was consistently greatest in animals on the high plane of nutrition and lowest in those on the low plane. Lactation did not appear to have a major effect on the rate of decline in the tissue concentrations of these compounds. No significant (P greater than 0.05) relationships were found between the concentrations of HCE or OCD in the subcutaneous fat and either milk or blood at any stage of the experiment. At slaughter, from 18 to 24 months after the commencement of the experiments, significant correlations (P less than 0.05) were found among concentrations of HCE and OCD in subcutaneous fat, renal fat and fat from the bone marrow.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Bovinos/metabolismo , Clordano/análogos & derivados , Epóxido de Heptaclor/análisis , Heptacloro/análogos & derivados , Residuos de Plaguicidas/análisis , Tejido Adiposo/análisis , Tejido Adiposo/metabolismo , Animales , Clordano/análisis , Clordano/sangre , Clordano/metabolismo , Dieta , Femenino , Epóxido de Heptaclor/sangre , Epóxido de Heptaclor/metabolismo , Lactancia/metabolismo , Masculino , Leche/análisis , EmbarazoRESUMEN
The elimination kinetics of organochlorine compounds (DDE, lindane, aldrin, heptachlor epoxide and heptachlor) from day 2 to day 10 of breast feeding was studied in 39 volunteers who had a baby in the Maternity Department in Nancy. If there was any contamination of the mothers' milk with DDT, the levels were below the level of detection. In contrast, contamination with DDE was high (112.6 ng/g fat content) on day 2, although it decreased rapidly, to 38.6 ng/g by day 3. On day 2, contamination with lindane, aldrin, heptachlor epoxide and heptachlor averaged 43.8, 23.5, 25.4 and 7.4 ng/g fat, respectively, and the levels showed a linear decrease on subsequent days in all cases except that of heptachlor, for which no significant negative correlation with time could be demonstrated. A breast-fed infant thus absorbs measurable quantities of pesticides but not in excess of the acceptable daily doses. Levels of contamination of human milk in France are lower than those reported in Canadian and Italian studies but are higher than the levels in formulated milk.
Asunto(s)
Insecticidas/metabolismo , Leche Humana/metabolismo , Aldrín/metabolismo , Lactancia Materna , Diclorodifenil Dicloroetileno/metabolismo , Femenino , Heptacloro/metabolismo , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/metabolismo , Humanos , CinéticaAsunto(s)
Encéfalo/metabolismo , Calcio/fisiología , Epóxido de Heptaclor/farmacología , Heptacloro/análogos & derivados , Neurotransmisores/metabolismo , Sinaptosomas/metabolismo , Adenosina Trifosfatasas/antagonistas & inhibidores , Animales , Encéfalo/ultraestructura , Radioisótopos de Calcio , Glutamatos/metabolismo , Epóxido de Heptaclor/metabolismo , Técnicas In Vitro , Masculino , Sistema Nervioso/metabolismo , RatasAsunto(s)
Carcinógenos , Epóxido de Heptaclor/toxicidad , Heptacloro/análogos & derivados , Heptacloro/toxicidad , Contaminantes Atmosféricos , Animales , Embrión de Pollo , Pollos , Femenino , Contaminación de Alimentos , Heptacloro/metabolismo , Epóxido de Heptaclor/metabolismo , Humanos , Neoplasias Hepáticas/inducido químicamente , Masculino , Ratones , Mutágenos , Neoplasias Experimentales/inducido químicamente , Ratas , Riesgo , Teratógenos , Contaminantes Químicos del AguaAsunto(s)
Insecticidas/análisis , Leche Humana/análisis , Residuos de Plaguicidas/análisis , DDT/metabolismo , Diclorodifenil Dicloroetileno/metabolismo , Dieldrín/metabolismo , Femenino , Contaminación de Alimentos/análisis , Heptacloro/metabolismo , Epóxido de Heptaclor/metabolismo , Hexaclorociclohexano/metabolismo , Humanos , Isomerismo , Missouri , EmbarazoRESUMEN
The estuarine fish, spot (Leiostomus xanthurus), was exposed to 0.27, 0.52, 1.01, 1.99, and 3.87 mug/liter technical grade heptachlor (65% heptachlor, 22% trans-chlordane, 2% cis-chlordane, 2% nonachlor, and 9% unidentified compounds) for 24 days in a flowthrough bioassay, followed by 28 days in heptachlor-free seawater. Concentrations of heptachlor, heptachlor epoxide, and trans- and cis-chlordane in edible tissues were monitored at day 3 and weekly thereafter throughout the bioassay and at the end of the postexposure period. All four chemicals were accumulated by spot. Maximum concentrations of heptachlor were observed on day 3; maximum concentrations of the other three compounds were observed on day 17. The average bioconcentration factors for heptachlor and trans-chlordane were 3,600 and 4,600, respectively. Only 10% or less of the maximum concentrations of heptachlor, heptachlor epoxide, and trans-chlordane accumulated during the exposure period remained after 28 days in pesticide-free seawater; an average of 35% of the cis-chlordane remained. Relative total amounts of heptachlor and cis-chlordane changed during the exposure and post-exposure periods. Nearly all of the heptachlor was eliminated or metabolized to its epoxide. Cis-chlordane, which averaged 4-7% of the total residues (chlordanes and heptachlors) in edible tissues during the exposure, increased to 18-23% of the total residues by the end of the postexposure period.