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At least 19 recordsLinked to original sources
PubMed1989

Sexual behavior of intact female rats after treatment with o,p'-DDT or p,p'-DDT.

Sexual behavior of adult, female rats was tested following treatment with o,p'-DDT or with p,p'-DDT during either diestrus or proestrus. Both chlorinated compounds decreased lordosis behavior, but o,p'-DDT did so only after treatment on diestrus. p,p'-DDT in contrast, decreased sexual behavior under all treatment conditions. o,p'-DDT may have altered behavior by disrupting the estrous cycle while p,p'-DDT had a major effect on the female's proceptivity and receptivity without modifying vaginal cyclicity. p,p'-DDT disrupted sexual behavior at doses as low as 25 mg/kg while 100 to 200 mg/kg o,p'-DDT were required. Since commercially prepared DDT contained a predominant proportion of p,p'-DDT, these results suggest that many reproductive effects of DDT may have resulted from p,p'-DDT rather than from o,p'-DDT.

Animals↗
PubMed2001

Anaerobic biodegradation of DDT residues (DDT, DDD, and DDE) in estuarine sediment.

The potential for anaerobic biodegradation of 1,1,1-trichloro-2,2-bischlorophenylethane (DDT), 1,1-dichloro-2,2,-bischlorophenylethane (DDD), and dichlorodiphenylchloroethylene (DDE) in anoxic sediment slurries collected from the Keelung River was investigated in this study. o,p'- and p,p'-DDT were dechlorinated to o,p'- and p,p'-DDD, respectively, and then transformed to other compound(s). 1-Chloro-2,2-bis (p-chlorophenyl) ethylene (DDMU) and trace amount of dichlorobenzophenone (DBP) were detected in sediment slurries amended with p,p'-DDT or p,p'-DDD. DDMU was also detected in sediment slurries amended with p,p'-DDE. The relative transformation rates for both o,p'- and p,p'-isomers of DDT, DDD, and DDE were DDT>DDD>DDE. Re-addition of DDT, DDD, or DDE to the sediment slurries after initial removal enhanced the respective dechlorination rates. The transformation rates of the p,p'-isomers of both DDT and DDD were faster than those of the respective o,p'-isomers. p,p'-DDT dechlorination in the p,p'-DDT-adapted sediment slurries were inhibited by the addition of molybdate, or molybdate plus sulfate, but not inhibited by the addition of sulfate. Addition of bromoethane-sulfonic acid (BESA) slightly inhibited p,p'-DDT dechlorination. Non-adapted sediment slurries lost the ability to dechlorinate pentachlorophenol during adaptation to p,p'-DDT. p,p'-DDD was the major transformation product of p, p'-DDT in 3,4,4',5-tetrachlorobiphenyl-adapted sediment slurries, which suggested that the microbial community in the 3,4,4',5-CB-adapted sediment was unable to remove chlorine from the aromatic rings of p,p'-DDT.

Alkanesulfonic Acids↗
PubMedDate not supplied

Effect of single and repeated in vitro exposure of ovarian follicles to o,p'-DDT and p,p'-DDT and their metabolites.

The aim of the presented study was to compare the effect of o,p'-DDT [1,1-dichloro-2,2-bis-(p,p'-chlorophenyl)-ethylene] and p,p'-DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)-ethane] and their metabolites DDE and DDD on estradiol secretion by ovarian follicles, the target organs of environmental estrogens. Theca interna (Tc) and granulosa cells (Gc) were collected from medium size porcine follicles and cultured as a monolayer. The cells were initially cultured for 24 h to allow attachment to the plates and then media were changed for the new ones and o,p'-DDT and p,p'-DDT and their metabolites: o,p'-DDE, p,p'-DDE and o,p'-DDD were added at doses of 4, 40, 400 ng and 4 microg/ml medium to investigate dose-dependent effects. Media were collected after 24 h and frozen for estradiol content determination. When the effect of single and repeated exposure was investigated, the lowest dose of 4 ng/ml and the highest one of 4 microg/ml were chosen on the basis of the results of Experiment 1. o,p'-DDT exerted antiestrogenic action at all doses used while its metabolites and p,p'-DDT and its metabolites decreased estradiol secretion only when present in the medium at a dose of 4 ng/ml. The highest doses caused the increase in estradiol secretion. Parent o,p'-DDT and its metabolites showed antiestrogenic action after single exposure to 4 ng/ml while parent p,p'-DDT and its metabolites caused estrogenic action. All investigated compounds, except o,p'-DDT, increased estradiol secretion after single exposure to the dose of 4 microg/ml. Repeated exposure resulted in a massive antiestrogenic action of all investigated chemicals. In conclusion, our study points to time-dependent effect of DDT and its metabolites on ovarian follicles with the strongest estrogenic properties observed after single exposure and antiestrogenic action caused by repeated exposure. Given the duration of folliculogenesis, one can imagine many different potential mechanisms by which DDT could influence steroidogenesis.

Animals↗
PubMed2000

Transfer of DDT and metabolites from fruit orchard soils to American robins (Turdus migratorius) twenty years after agricultural use of DDT in Canada.

Wildlife contamination studies found high levels of DDT and associated metabolites in bird eggs from Canadian orchard sites during the early 1990s. The present study investigated local dietary uptake of DDT and geographic variability in tissue concentrations in the same orchards. A soil-earthworm-robin food chain was chosen for study, as early surveys showed that robins contained the highest levels of DDT of several avian species and because published research indicated that earthworms were a probable dietary exposure route. Organochlorine pesticides and PCBs were measured in soil, earthworm, robin egg, and robin nestling samples collected from fruit orchards and reference sites. High average DDE (soil: 5.2 mg/kg; earthworm: 52 mg/kg; robin egg: 484 mg/kg dry weight) and DDT (soil: 9.2 mg/kg; earthworm: 21 mg/kg; robin egg: 73 mg/kg dry weight) concentrations in Okanagan (British Columbia) samples confirmed that previously recorded contamination was common in the region. Concentrations detected in Simcoe, Ontario, orchards were not as high but were still significantly elevated relative to levels in soils and robins from reference areas. Significant positive linear regressions between soil and earthworm concentrations and consistent trends in food chain accumulation suggested that robins were acquiring DDT and metabolite (DDTr) burdens locally. Low concentrations of DDT and DDTr in robin eggs collected from nests in nearby nonorchard and post-DDT orchard habitats suggested that the local sources were in orchards. Persistence of DDT in orchard food chains is likely due to a combination of retarded degradation rates for DDT in soil and its extensive use historically. DDT concentrations in some robin eggs and earthworms were at levels comparable to those observed in field studies where mortality or reproductive effects occurred.

Agriculture↗
PubMed1990

Levels of DDT and metabolites in breast milk from Kwa-Zulu mothers after DDT application for malaria control.

Concentrations of DDT, DDE and DDD were determined in the breast milk of Kwa-Zulu mothers residing in two different areas--with and without annual intra-domiciliary applications of DDT for the interruption of malaria transmission (exposed and control groups, respectively). While no significant change in levels with time was found in the control group, both DDT and DDE in breast milk of the exposed group increased after DDT application and this continued for three more months, after which it did not decrease appreciably. Percentage DDT increased from 42.57% (sigma DDT = 12.21 mg/kg milk fat) before spraying to 50.87% (sigma DDT = 13.79 mg/kg milk fat) following DDT application. At 6 and 9 months after the application it was 45.85% (sigma DDT = 19.49 mg/kg milk fat) and 43.27% (sigma DDT = 18.34 mg/kg milk fat), respectively. These results suggest a risk to the health of the infants in the exposed group.

Adult↗
PubMed1971

Nonconversion of o,p'-DDT to p,p'-DDT in rats, sheep, chickens, and quail.

The finding of appreciable quantities of p,p'-DDT after feeding o,p'-DDT to rats led to the proposal of a theory, that an isomeric metabolic conversion occurs. The presence of p,p'-DDT as an impurity in supposedly pure samples of o,p'-DDT is the correct explanation for the appearance of p,p'-DDT. Purified o,p'-DDT and (14)C-labeled o,p'-DDT yielded no data to support the idea that o,p'-DDT is converted to the p,p'-DDT isomer.

Adipose Tissue↗
PubMed2000

Effects of long-term contamination of DDT on soil microflora with special reference to soil algae and algal transformation of DDT.

DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and its principle metabolites, DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) are widespread environmental contaminants but little information is available concerning their effects on non-target microflora (especially microalgae and cyanobacteria) and their activities in long-term contaminated soils. For this reason a long-term DDT-contaminated soil was screened for DDT residues and toxicity to microorganisms (bacteria, fungi, algae), microbial biomass and dehydrogenase activity. Also, five pure cultures isolated from various sites (two unicellular green algae and three dinitrogen-fixing cyanobacteria) were tested for their ability to metabolise DDT. Viable counts of bacteria and algae declined with increasing DDT contamination while fungal counts, microbial biomass and dehydrogenase activity increased in medium-level contaminated soil (27 mg DDT residues kg(-1) soil). All the tested parameters were greatly inhibited in high-level contaminated soil (34 mg DDT residues kg(-1) soil). Species composition of algae and cyanobacteria was altered in contaminated soils and sensitive species were eliminated in the medium and high contaminated soils suggesting that these organisms could be useful as bioindicators of pollution. Microbial biomass and dehydrogenase activity may not serve as good bioindicators of pollution since these parameters were potentially influenced by the increase in fungal (probably DDT resistant) counts. All the tested algal species metabolised DDT to DDE and DDD; however, transformation to DDD was more significant in the case of dinitrogen-fixing cyanobacteria.

Journal Article↗
PubMed2000

Uptake and phytotransformation of o,p'-DDT and p,p'-DDT by axenically cultivated aquatic plants.

The uptake and phytotransformation of o,p'-DDT and p,p'-DDT were investigated in vitro using three axenically cultivated aquatic plants: parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza), and elodea (Elodea canadensis). The decay profile of DDT from the aqueous culture medium followed first-order kinetics for all three plants. During the 6-day incubation period, almost all of the DDT was removed from the medium, and most of it accumulated in or was transformed by these plants. Duckweed demonstrated the greatest potential to transform both DDT isomers; 50-66% was degraded or bound in a nonextractable manner with the plant material after the 6-day incubation. Therefore, duckweed also incorporated less extractable DDT (32-49%) after 6 days than did the other plants. The capacity for phytotransformation/binding by elodea is between that of duckweed and parrot feather; approximately 31-48% of the spiked DDT was degraded or bound to the elodea plant material. o,p'-DDD and p,p'-DDD are the major metabolites in these plants; small amounts of p,p'-DDE were also found in duckweed (7.9%) and elodea (4.6%) after 6 days. Apparently, reduction of the aliphatic chlorine atoms of DDT is the major pathway for this transformation. This study, which provides new information on plant biochemistry as related to pollutant accumulation and phytotransformation, should advance the development of phytoremediation processes.

Biotransformation↗
PubMed2003

Organo-chlorine pesticide (DDT and HCH) residues in the Taihu Lake Region and its movement in soil-water system I. Field survey of DDT and HCH residues in ecosystem of the region.

The use of organo-chlorine (DDT and HCH) has been banned in China for 20 years. A field survey was carried out during 1999-2000 in the Taihu Lake Region. Organo-chlorine pesticide (OCP) residues in soil, water, fish and sediment samples were investigated. DDT was detected in 5 out of 10 samples with concentration ranging from 0.3 to 5.3 microg/kg in the surface (0-15 cm) layer, 6 out of 10 with 0.5 to 4.0 microg/kg in the subsoil layer (16-30 cm), and 4 of 10 with 0 to 2.7 microg/ kg in the deep soil layer (31-50 cm). Results for HCH residues in soil samples were similar to those of DDT. These results indicate that OCP residues in 0-50 cm profile had been leached out or degraded to safe level. In river water DDT was detected in 10 out of 13 samples ranging from 0.2 to 9.3 microg/l, with an average of 1.0 microg/l. While HCH was detected in 12 out of 13 samples ranging from 0.02 to 36.1 microg/l, with an average 5.6 microg/l. DDT residues in sediment ranged from 0.1 to 8.8 microg/kg, while HCH ranged from 0.3 to 66.5 microg/kg. DDT residues in fish body ranged from 3.7 to 23.5 microg/kg and HCH ranged from 3.7 to 132 microg/kg. These results demonstrate an accumulation through food chain (from soil-water-sediment-microbes-crop-fish-... etc.), also that HCH residues are generally more persistent than DDT residues. However, all these data are well below than the state warning standard limit.

Animals↗
PubMed2000

Correlation of glutathione S-transferase and DDT dehydrochlorinase activities with DDT susceptibility in Anopheles and Culex mosquitos from northern Thailand.

Comparative DDT-susceptibility status as well as glutathione S-transferase activity and DDTase activity of Anopheles minimus (A). An. annularis and Culex quinquefasciatus were investigated to ascertain the role of these enzymes in DDT-resistance. The standard WHO susceptibility test kits was used to discriminate between resistant and susceptible populations. GST activity was measured in microtiter plates whereas DDTase activity was determined by HPLC quantitation of DDT metabolites. This is the first report of DDT-resistance in the Thai malaria vector, An. minimus species A. A positive correlation of DDT-resistance and DDTase activity was observed in this species as well as in the suspected vector, An. annularis. However, GST activity was not correlated to DDT-resistance in either species. Statistical analysis and scatter plots demonstrated the non-correlation between DDTase and GST activity in An. annularis. Studies in Culex quinquefisciatus revealed difference in GST/ DDTase and the relationship to DDT-resistance compared to the anopheline species. The Culex GST activity is correlated to DDTase activity. These results suggested that a positive correlation of GST and DDTase activity might be species dependent.

Animals↗
PubMed1977

Effects of reducing DDT usage on total DDT storage in humans.

Agricultural uses of the insecticide DDT were cancelled by the U.S. Environmental Protection Agency December 31, 1972. However, the domestic use of DDT had begun to decline before this action. Beginning July 1969, residues of DDT and its metabolites were measured in human adipose tissue collected through an annual national survey. Levels of total DDT equivalent residues in human adipose have decreased slightly, but the frequencies of finding DDT or its metabolites have remained high. The most marked decline in residue concentration has been found in the youngest age group (0-14 years). Approximately 80 percent of the total DDT equivalent found in this survey was DDE. These data show that the reduction of the agricultural uses of DDT has decreased human exposure to and storage of this chemical.

Adipose Tissue↗
PubMed2002

Reductive metabolism of p,p'-DDT and o,p'-DDT by rat liver cytochrome P450.

The in vitro metabolism of p,p'-DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], an important environmental pollutant, was examined in rat liver, focusing on reductive dechlorination. When p,p'-DDT was incubated with liver microsomes of rats in the presence of NADPH or NADH, a dechlorinated metabolite, p,p'-DDD [1,1-dichloro-2,2-bis(4-chlorophenyl)ethane], was formed under anaerobic conditions together with a dehydrochlorinated metabolite, p,p'-DDE [1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene]. p,p'-DDE was also formed from p,p'-DDD by liver microsomes. The dechlorinating activity was inhibited by carbon monoxide, metyrapone, and SKF 525-A (proadifen hydrochloride), but the dehydrochlorinating activity was unaffected. The reductase activity toward p,p'-DDT was induced by the pretreatment of rats with phenobarbital and dexamethasone. The dechlorination was catalyzed enzymatically by recombinant cytochrome P450 2B1, 3A1, 2B6, and 3A4. When p,p'-DDT was incubated with liver microsomes of rats in the presence of both a reduced pyridine nucleotide and FMN, p,p'-DDD was also formed under anaerobic conditions. In this case, the dechlorinating activity was not abolished when the microsomes were boiled. The reductase activities were inhibited by carbon monoxide. Hematin exhibited reductase activity toward p,p'-DDT in the presence of NADH and FMN. The activity of hematin was also supported by FMNH(2). The reductive dechlorination also seems to proceed nonenzymatically with the reduced flavin, catalyzed by the heme group of cytochrome P450. Similar enzymatic and nonenzymatic reducing activities were observed toward o,p'-DDT [1,1,1-trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)ethane].

Animals↗
PubMed1987

Inheritance of DDT dehydrochlorination and of a mechanism restricting uptake of DDT in the mosquito Aedes aegypti.

Crosses and backcrosses were made between the T8 dichlorodiphenyltrichloroethane (DDT) resistant strain and NS susceptible strain. Each generation was tested for resistance, for internal levels of DDT and dichlorodiphenyldichloroethylene (DDE) (thus "DDT uptake" (DDT + DDE) and percentage DDT dehydrochlorination in vivo), and for DDT dehydrochlorination in vitro, both at the larval and adult stages. The patterns of inheritance of uptake and dehydrochlorination were different. At both life stages, dehydrochlorination (both in vivo and in vitro) was intermediate in the F1, reverting to or exceeding the parental strains in the backcrosses except in adult tests on the backcrosses to the susceptible strain where it remained intermediate. Uptake increased very substantially in the F1 compared with either parental strain and was also high in the backcrosses. This was interpreted as being due to the disruption of an uptake-restricting mechanism in T8 brought about by outcrossing. Larval resistance in the various generations was correlated significantly with dehydrochlorination, both in vivo and in vitro but bore no clear relation to uptake. Resistance in adults was found not to be correlated significantly with either.

Aedes↗
PubMed1979

Residues of DDT in a Norwegian fruitgrowing district two and four years after the termination of DDT usage.

This study describes the extent of DDT contamination in a typical fruit growing district in Norway two and four years after the DDT ban. Residues of DDT in man, dairy cows and soil were about five to one hundred times higher than in the control groups, while residues found in samples from the marine biota were the same or moderately higher (Figure 3). The residues of DDT in cows, gulls and parts of the marine samples showed a significant decrease from 1972 to 1974, while the level in soil was almost constant. The amount of DDE had increased considerably in 1974 for all the species except for the gull, although not to the same degree. The distribution of DDE, DDD and DDT in soil were almost constant during the two years of sampling.

Adipose Tissue↗
PubMed1975

DDT and immunological responses. 3. Reduced anaphylaxis and mast cell population in rats fed DDT.

Previous work showed that anaphylaxis, mast cell population, and tissue histamine content are reduced in guinea pigs given DDT injections. This study was intended to determine whether dietary intake of DDT causes similar effects. Rats immunized with diphtheria toxoid and fed diets containing DDT at 20 and 200 ppm levels for 31 days did not show effects on their serum antitoxin titers, but the numbers of metachromatically stained, histamine-containing mast cells in mesenteries were reduced: in the 20 ppm group by 46% and in the 200 ppm group by 61%. The severity of anaphylactic shock was also reduced in proportion to the DDT dietary levels, and, thus, the magnitude of mast cells. Apparently, daily dietary DDT intake above 2.2 mg DDT/kg of body weight alters the physiology of mast cells in the rat, and thus affects histamine-mediated reactions.

Anaphylaxis↗
PubMed1985

Estrogenic activity of DDT: estrogen-receptor profiles and the responses of individual uterine cell types following o,p'-DDT administration.

The administration of o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT) to immature rats stimulates DNA synthesis and cell division in the uterine luminal epithelium (LE), stroma (S), and myometrium (M). The time course of DNA synthesis/cell division in the S and M is similar following administration of o,p'-DDT or 17 beta-estradiol, but the maximum response following pesticide treatment is only 70% of that produced by the hormone. In the LE both compounds yield the same maximum response, but the time course of DNA synthesis/cell division is delayed following o,p'-DDT administration relative to 17 beta-estradiol treatment. The patterns of estrogen receptor retention in uterine nuclei following o,p'-DDT administration are prolonged relative to those observed after 17 beta-estradiol treatment. o,p'-DDT thus produces the uterine hyperplasia characteristic of estrogens, but the magnitude and timing of the response is dependent on the specific cell type observed and is different from that produced by estradiol.

Animals↗
PubMed1995

Determination of a tolerable daily intake of DDT for consumers of DDT contaminated fish from the lower Yakima River, Washington.

DDT, DDE, and DDD have been detected at elevated concentrations in sediments and fish of the Yakima River, its tributaries and drainages. An assessment was conducted to evaluate the public health significance of eating fish from the river. This was accomplished by establishing a daily intake level of DDT for the population of greatest concern, and comparing this level to a tolerable daily intake. The most sensitive and highly exposed group was determined to be breastfeeding infants. Infant daily intakes of DDT, based on estimated mother's DDT-breast milk levels, were compared to a recommended tolerable daily intake. Results indicate that mothers who frequently consume Yakima River bottom-feeding fish could have breast milk DDT concentrations sufficiently high to expose their infants to levels above the tolerable daily intake.

Animals↗