DDT Treatment Research Articles

The Effect of DDT Contamination on the Productivity of a Cultivated Forest Soil in the Sub-Humid Tropics

(1) Seed yields of cowpea (Vigna unguiculata (L.) Walp) were assessed in each of two annual growing seasons over the 4-year period 1973 to 1976 from experimental plots under continuous cultivation on land newly cleared from bush regrowth in Ibadan, S. Nigeria. No fertilizer was applied throughout the experimental period. One set of plots was sprayed weekly with DDT during both growing seasons of each year and one received DDT treatment only in the first growing season of each year. The yield from untreated controls was also monitored. (2) Cowpea seed yields varied considerably from season to season and year to year in untreated plots due to differences in pest incidence and climatic conditions. The cowpea yield over the 4 years was considerably higher in the DDT treated plots but the decline of yield with time was faster than in untreated plots and by the seventh season of application DDT application did not significantly enhance cowpea yields. (3) Maize was cultivated without pesticide protection during the first season of 1977 in all plots as an additional indicator of soil fertility before the plots were allowed to return to bush fallow. Crop production was lower in plots previously treated with DDT than in untreated plots, and although soil nutrients were depleted by the continuous cultivation there was no greater depletion in the plots with higher yields. It is suggested that the more rapid decline in fertility of plots with a history of DDT treatment may be associated with pesticide effects on the soil biota.

Toxicity and retention of DDT in adult frogs, Rana temporaria L.

The acute LD 50 value of DDT in adult summer frogs was only 7·6 mg/kg.The symptoms of poisoning caused by DDT point to nervous damage. The toxicity was further increased by starving. The retention of DDT was followed using ( 14C)-labelled DDT. It accumulated most in tissues containing fat. Thus the fat body and liver retained much of the DDT while only a very small amount was found in skeletal or heart muscle. In female frogs a large quantity of DDT is stored in the ovary, its large size and high fat content possibly accounting for this phenomenon. Moderate amounts of DDT were found in kidneys and nervous tissue. In addition, an autoradiographical study revealed considerable radioactivity in bones and spleen. Starved animals retained higher amounts of DDT in their tissues, with the exception of the fat body, than did the fed animals. DDT was found to disappear extremely slowly. Its disappearance was, however, enhanced by previous DDT treatment since DDT-treated animals retained much less of the test dose than did the untreated controls. It is thus possible that DDT induces the activity of drug-metabolising enzymes which may lead to increased biliary excretion of the drug.

The effect of dietary o,p′-DDT on ureagenesis from ammonia by isolated rat hepatocytes

Hepatocytes isolated from rats which had been fed 1000 ppm o,p′-DDT for 2 weeks and starved for 48 hr exhibited markedly reduced rates of urea synthesis and citrulline accumulation when incubated with 10 m m NH 4Cl and 10 m m ornithine. The addition of 10 m m lactate to such incubations stimulated the rate of ureagenesis by both control and DDT-treated cells to nearly the same degree but did not eliminate the difference in rates of urea synthesis between control and DDT-treated cells. The activities of carbamoylphosphate synthase, ornithine carbamoyltransferase, arginine synthetase, and arginase were similar in livers from control and DDT-treated rats. The kinetics of the stimulation of urea synthesis by exogenous ornithine were similar with hepatocytes from both control and DDT-treated rats. Mitochondria isolated from the livers of control and DDT-treated rats exhibited similar rates of citrulline synthesis from ammonia and ornithine as well as similar responses to N-acetylglutamate and 2,4-dinitrophenol. These results suggest that DDT treatment may produce alterations in the kinetic behavior of urea cycle enzymes which are not detected in the standard assays of these enzymes or DDT treatment may interfere with the intermitochondrial transport processes required during ureagenesis from ammonia.

A method for confirming organochlorine pesticide residues in wildlife

Methods involving chemical reactions have been used frequently for the confirmation of organochlorine pesticide residues. Dehydrochlorination or dechlorination in alkaline solution is one such method. KLEIN et al. (1963), HAMMENCE et al. (1965), SANS (1967), and HOLDEN and MARSDEN (1967) used alcoholic alkali to convert DDT and similar compounds to their corresponding olefins. YOUNG and BURKE (197Z) and KRAUSE (1972) found that treatment of DDT and DDD with alcoholic KOH converted the DDT and DDD to olefinic derivatives. The authors reported that the hexachlorocyclohexane (HCH) isomers (~(,~,$,[) were transformed into unidentified compounds. The former authors also noted that dieldrin and polychlorinated biphenyls (PCBs) were unchanged by this treatment. MENDOZA et al. (1968) treated residues from plant extracts with sodium methylate followed by gas-liquid chromatography (GLC) and thin layer chromatography (TLC) to confirm the presence of certain pesticides. TAYLOR and KEENAN (1970) detected unchanged hexachlorobenzene (HCB) and one unidentified product in samples containing HCB that had been treated with alcoholic KOH or sodium methoxide. COLLINS et al. (197Z) found that HCB produced pentachlorophenyl propyl ether when it was treated with KOH in 1 propanol. The derivative was found to have a longer retention time (GLC) than HCB. HOLDRINET (1974) refluxed HCB with 0.ZN KOH in ethylene glycol, to produce pentachlorophenol (PCP). The PCP was esterified with diazomethane to give the methyl ether derivative. BAKER (1973) demonstrated that HCB was converted to a monoethoxypentachlorobenzene (MEPCB) derivative when it was refluxedwith sodium ethoxide. The present study deals with the confirmation of HCB and other organochlorine residues in wildlife samples by reactions involving the use of sodium ethoxide.

Biodegradation of litter in Eucalyptus pauciflora communities—II. Fungal succession in fungicide- and insecticide-treated leaves

Fungal succession on untreated and fungicide- and insecticide-treated leaves of Eucalyptus pauciflora was compared. Natural succession on untreated leaves fits the general scheme for succession on deciduous tree leaves. Initial colonizers are species of Coelomycetes and Moniliales. When the numbers of Coelomycetes decrease in the late stages of decomposition, the frequency of Penicillium species and species of Zygomycetes increases. The succession is affected only marginally by DDT and dieldrin treatment while benomyl severely restricts the occurrence of most fungal species. The effect of benomyl persists even after exposure for 48 weeks in the field.

Carcinogenicity of DDT (dichlorodiphenyl trichloroethane) in pure inbred Swiss mice.

Inbred Swiss mice were treated with technical DDT (1) orally with the diet or by intubation; (2) subcutaneously and (3) by skin painting. The total duration of the experiment was 80 weeks. There was no difference in body growth and mortality between the experimental and control groups. Toxic manifestations of DDT were observed in treated mice in the form of tremor, convulsions and corneal opacity usually after 40 weeks. Oral and subcutaneous DDT treatment resulted in a significant increase in the incidence of tumours mainly of lymphoid tissues, lung and liver. The highest tumour incidence was recorded in the group of mice receiving DDT by subcutaneous injections. Males and females were equally susceptible. No evidence of carcinogenicity was observed in the painted group.

Scanning and transmission electron microscopic changes associated with duck and chicken shell gland cilia after p, p′-DDT administration

DDT has been reported to cause eggshell thinning in a variety of avian species. The domesticated mallard duck ( Anas platyrhynchos) is susceptible to DDT-induced eggshell thinning, but the domesticated chicken ( Gallus domesticus) is not. Scanning (SEM) and transmission (TEM) electron microscopic examination of duck and chicken shell glands revealed surface morphological variations after treatment with p, p′-DDT. Cilia on shell gland epithelia of control birds contained an irregular, bulbous surface, whereas cilia of shell glands from p,p′-DDT-treated birds were smoother. This same variation, associated with p, p′-DDT treatment, occurred when, with the use of a biopsy technique, the same birds were used as their own controls. The bulbous surface feature is suggestive of a secretory function of the cilia. p, p′-DDT treatment abolishes this structural modification. This change in morphology was consistent in both p,p′-DDT-sensitive and -nonsensitive species.

Effect of exercise on the responses of rats to DDT.

Two groups of 30 male weanling rats were maintained on a nutritionally adequate diet containing 45% carbohydrate, 16% fat, and 29% protein with or without 1 ppm added DDT. At 100 days of age the two groups were subjected to an oral glucose tolerance test. The groups were then subdivided and half of each group was forced to run 1/16 mi/30 min-day on a treadmill. At 190 days of age the glucose tolerance test was repeated. The animals were killed at 200 days of age, and the lipid content of the serum, liver, and carcass was determined. Serum insulin levels and the DDT levels in the adipose tissue reflected the DDT content of the diet, and no differences in these levels were demonstrated with the addition of the exercise treatment. DDT treatment resulted in lower serum and liver cholesterol and serum insulin levels in sedentary rats. Exercise lowered liver cholesterol and serum insulin in non-DDT-treated rats. When both treatments were imposed, serum insulin cholesterol levels rose. Significant DDT-exercise interaction effects were observed on the glucose tolerance, serum and liver cholesterol, and serum insulin levels.

Field Evaluations of Acephate and Dimilin™ Against the Douglas-fir Tussock Moth12

Efficacy of acephate at 1.0 and 0.5 lb AI/2 gal/acre against Orgyia pseudotsugata (McDunnough) was compared to DDT at 0.75 lb AI/gal/acre on replicated 20 acre plots in 1974. Acephate at 1.0 lb AI/gal/acre and Dimilin™{ [1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl) urea] at 0.25 lb AI/gal/acre were evaluated on replicated 150-acre plots in 1975. In both experiments, all treatments caused significant reductions in larval populations. In 1974, the 1.0 lb acephate treatment resulted in populapation reductions which were comparable to the DDT treatment; however, the larval knockdown was faster for DDT. Both acephate and Dimilin provided excellent population control and foliage protection in 1975.

The effect of p,p′-dichlorodiphenyltrichloroethane on levels of guanosine 3′,5′-cyclic monophosphate and adenosine 3′,5′-cyciie monophosphate in two species of insects

Within 1 h after topical application of a convulsive dose (4 mug per fly, 47 mg/kg) of p,p'-dichlorodiphenyltrichloroethane (DDT) to the adult male of Sarcophaga bullata Parker, guanosine 3',5'-cyclic monophosphate (cyclic GMP) levels rose by 71.5% (P less than 0.05) in the head, 159.5% (P less than 0.01) in the thorax, and 23.4% (P greater than 0.05) in the abdomen compared to controls. Adenosine 3',5'-cyclic monophosphate (cyclic AMP) levels were not significantly affected by the DDT treatment. A convulsive dose (100 mug per larva, 250 mg/kg) of DDT applied to larvae of Mamestra configurata Wlk. caused the whole body level of cyclic GMP to rise by 81.6% (P less than 0.01) after 1 h, and by 95.9% (P less than 0.01) after 3 h. Levels of cyclic AMP were not affected. A hypothesis is advanced suggesting that an abnormally high rate of discharge of acetylcholine (and in the later stages of poisoning, its actual accumulation) at central cholinergic synapses causes cyclic GMP levels to rise, perhaps in post-synaptic cells. The elevated cyclic GMP-cyclic AMP ratio found in DDT-poisoned insects may be of fundamental importance in the complex sequence of events leading to tremor, hyperexcitability, paralysis, and death.

The mode of action of p, p′-DDT on mammalian mitochondria

In rats treated with single, sublethal doses of p, p′-DDT oxidative phosphorylation efficiency, respiratory activity and “latent” ATPase activity in liver and brain mitochondria were determined. A time- and dose-dependent decrease in oxidative phosphorylation efficiency was found. Time-dependent suppression of respiratory activity in state 3 was notice and a stimulation of mitochondrial ATPase activity 24 h after DDT treatment in liver and brain mitochondria was found. The correlation between time-dependent changes in the brain mitochondrial fraction and distribution of DDT in brain after a single, oral dose is discussed. It is suggested that changes in mitochondria were caused by DDT and its metabolites. It is concluded that the uncoupling of oxidative phosphorylation especially in brain mitochondria could be responsible

Possible involvement of cyclic amp-dependent protein kinase in p, p′-ddt-induced changes in hepatic metabolism

Administration of an acute dose of p, p-1,1,1-trichloro-2,2-bis ( p-chlorophenyl) ethane ( p, p′-DDT) (600 mg/kg, p.o.) resulted in a significant increase in hepatic adenylate cyclase activity (40 per cent) and endogenous cyclic AMP levels (31 per cent). Although the cytosol cyclic AMP-independent protein kinase activity was only slightly affected (18 per cent), the activity of the nucleotide-dependent enzyme was significantly decreased to 74 per cent of the control values. Whereas the protein kinase activity ratio (−cyclic AMP/+cyclic AMP) of this soluble enzyme was increased, the ability of the enzyme to bind [ 3H]cyclic AMP in vitro was significantly decreased after pesticide administration. As observed with the soluble enzyme, maximal stimulation of the crude nuclear protein kinase (1500 g pellet) was observed 1 hr after p, p′-DDT treatment, as indicated by changes in the phosphorylation of endogenous nuclear substrates and cyclic AMP-binding capacity. Studies with lower dosages of DDT revealed that a dose as low as 100 mg/kg was sufficient to produce statistically significant alterations in the activities of both the soluble and paniculate enzymes. In most cases, doubling the dosage (200 mg/kg) resulted in greater changes in these biochemical parameters. The present study supports the concept that the DDT-induced alterations in hepatic carbohydrate metabolism may be related to an initial stimulation of the hepatic cyclic AMP-adenylate cyclase-protein kinase system.

Alteration of induced cellular and humoral immune responses by pesticides and chemicals of environmental concern: Quantitative studies of immunosuppression by DDT, aroclor 1254, carbaryl, carbofuran, and methylparathion

Dose-dependent, immunosuppressive effects of continued dietary treatment of rabbits with DDT, Aroclor 1254, carbaryl, carbofuran, and methylparathion were studied. The animals were given a diet containing graded amounts of chemicals for 4 wk and challenged with sheep red blood cells and Freund's adjuvant. The testing followed for an additional 4 wk while the animals were maintained on the same diets as before. The most sensitive indication of immunosuppression was based on evaluation of lymphatic organs, primarily those dependent on thymus-derived lymphocytes. The chemical treatments resulted in a decreased count of plasma cells in popliteal lymph nodes (except with carbaryl), reduction of germinal centers in the spleen, and increasing atrophy of thymus cortex. These responses were generally scaled to increasing levels of the compounds tested. Hemolysin and hemagglutinin titers were not significantly affected by any of the chemical treatments nor were consistent trends observed. The antigen-induced increase in serum γ-globulin was consistently decreased with DDT, Aroclor, carbaryl, and carbofuran treatments, but only carbaryl produced significant changes (at 10 days postantigen). DDT groups showed significantly higher preantigen γ-globulin values which were less evident following antigen challenge. Skin sensitivity to tuberculin was decreased (except with carbaryl) but generally only at high dosages of the test chemicals. None of the compounds showed any effect on growth, food consumption, leucocyte count, or on organ to body weight ratios for liver, kidney, spleen, and adrenal, except for slight liver enlargement caused by Aroclor 1254.

Possible alternatives to DDT for control of plague thrips in apples

Seven insecticides were tested as possible alternatives to DDT for control of plague thrips, Thrips imaginis, in Granny Smith apples in a field trial at Bathurst Agricultural Research Station in October 1971. Thrips were moderately plentiful but the infestation was insufficient to impose severe pressure on the treatments. None of the treatments was as effective as the standard 0.1 per cent a.i. DDT. However, 0.1 per cent a.i. TDE, 0.066 per cent a.i. endosulfan, 0.06 per cent a.i. maldison, 0.2 per cent a.i. methoxychlor and 0.1 per cent a.i. tetrachlorvinphos were sufficiently effective to be considered as possible alternatives. Chlorcam 0.1 5 per cent a.i. and phosalone 0.06 per cent a.i. were less effective in reducing thrips numbers but phosalone was as effective as some other treatments in reducing damage to styles. In a separate sub-trial, using Granny Smith, Democrat and Jonathan varieties, maldison, endosulfan and methoxychlor were less repellent to bees than was the standard DDT treatment. TDE and tetrachlorvinphos were not significantly less repellent than DDT. The only significant tree injury was a severe browning and premature drop of petals on all three varieties when TDE and methoxychlor were sprayed at full bloom.

DDT induced chromosome mutations in mice--further testing.

Laboratory mice (Mus musculus L.) were investigated for DDT induced chromosome mutations. Twenty-four brown and Balb/c strain albino mice were intraperitoneally injected with 25, 50, 100 and 250 ppm (mg/kg body weight) of DDT in peanut oil, and killed 48 h later. Controls received either no injection or peanut oil only. Karyotypes from bone marow cells of femurs were analyzed for gaps, deletions, and stickiness. Data for chromosome aberrations were taken from 200 well spread cells per animal, and mitotic indices were calculated from 1000 cells per animal. Regression of aberrations on log DDT concentrations, and Dunnett's multiple comparison test were employed to determine the effect of DDT treatments. Gaps, stickiness and mitotic indices were not significantly affected by DDT treatments, but deletions and gaps plus deletions were significantly higher or approached the significant levels at 50 ppm and higher concentrations. DDT thus appears to act as a mutagen in concentrations encountered naturally in many secondary consumers.

DDT increases the aminoacyl-tRNA binding activity of liver pH 5 supernatant fraction

The incorporation of [ 14 C]phenylalanyl-tRNA into peptide was measured in cell-free preparations obtained from the liver of control rats and the liver of rats that had received DDT. Elongation factors 1 (EF 1) and 2 (EF 2), necessary for the binding of aminoacyl-tRNA to ribosomes and for the translocation of peptidyl-tRNA from the A site to the P site of ribosomes, were present in the pH 5 supernatant fractions of liver of control or DDT-treated rats and these fractions were incubated with saltwashed ribosomes obtained from the liver of control rats. The results provided evidence that the increased incorporation observed with the pH 5 supernatant fraction obtained from the DDT-treated rats could not be attributed to decreased ribonuclease activity or to increased EF 2 activity but was due to an increase in EF 1 activity. When EF 1 was separated from EF 2 by gel filtration chromatography, the activity of EF 1 from DDT-treated rats was greater than the activity of EF 1 from the control rats. Moreover, an increased binding of [ 14 C]phenylalanyl-tRNA to ribosomes was found in the preparations obtained four the liver of DDT-treated rats, in further support of the conclusion that aminoacyl-tRNA binding is increased in rat liver after DDT treatment.

A Special Case for DDT Treatment?

A Special Case for DDT Treatment?

The effects of long-term feeding of DDT to BALB-c mice.

AbstractA multigenerational study on the long‐term effects of three dose levels of DDT (2, 20 and 250 ppm in the diet) and one dose level of N‐nitrosodimethylamine (DMN) (0.0003% in the drinking water) was started in 1968. Each treatment was administered to two separate colonies of BALB/c mice. Treatment of parent mice started at 4‐5 weeks of age. The results observed in the first two generations are presented in this report. Survival in males was poor because of fighting. In females, the highest dose level of DDT produced liver‐cell tumours in 44% of the parent mice and 74% of the first generation mice, whereas no liver‐cell tumours were found in mice given the control diet, or lower dietary concentrations of DDT. Liver cell tumours did not give metastases, but grew after transplantation to syngeneic mice. The ability of DDT to induce liver‐cell tumours was identical in both colonies of mice given 250ppm DDT. Malignant lymphomas occurred in about 50% of the mice in all colonies given 0, 2 or 20 ppm DDT. In one of the two colonies given 250ppm DDT, the incidence of malignant lymphomas was 14%, whereas in the other it was 36%. The incidence of lung adenomas was not affected by DDT treatment. Tumours at sites other than liver, lymphatic system and lungs were highest in control mice and lowest in mice given 250 ppm DDT. However, no linear dose‐response was found, and the decrease was more obvious in the parental than in the first generation. A study on the combinations of tumours in mice with more than one tumour and an analysis of litter distribution of liver‐cell tumour‐bearing mice did not reveal any particular trend in the distribution of liver‐cell tumours. The quantitative aspects of tumour induction by DDT in BALB/c mice are compared with data from previous studies in mice. DMN consistently produced lung adenomas, liver blood cysts and haemangioendotheliomas.

Stimulation of hepatic microsomal drug-metabolizing enzymes in mice by 1,1,1-trichloro-2,2-bis( p-chlorophenyl)ethane (DDT) and 3,4-benzpyrene

In previous reports from this laboratory it was shown that DDT or benzpyrene apparently did not stimulate hepatic drug metabolism in mice. Other investigators have recently reported that mice can respond to DDT or benzpyrene treatment by exhibiting increased levels of hepatic drug metabolizing enzymes. We reinvestigated the effect of DDT or benzpyrene on the strain of mice we had previously used. We found that apparent resistance of mice to hepatic microsomal enzyme induction by DDT or benzpyrene was related to the doses of the DDT or benzpyrene used, the duration of treatment with these inducers, and the short-lived duration of the induction.

The effect of DDT treatment on the levels of DDT-dehydrochlorinase in Musca domestica

1. 1. The levels of DDT-dehydrochlorinase (E.C. 4.5.1.1) measured in the soluble fraction obtained from homogenates of Musca domestica L. are increased after treatment of the insect with DDT. 2. 2. The increase enzymatic activity is shown to be paralleled by an increased de novo synthesis of the enzyme protein. 3. 3. Experiments using protein synthesis inhibitors suggested that this enhanced enzyme synthesis is dependent on RNA synthesis and gave further support to the idea of an inductive phenomenon.