DDT exposure

DDT exposure to human cancers. The lARC has determined that there is sufficient evidence for the carcinogenicity of DDT in experimental animals and that it is possibly carcinogenic to humans. ... 

In mice, exposure to DDT during gestation and in the neonatal stage has also caused developmental neurotoxicity, in the form of behavioral deficits in the learning process, that persisted into adulthood. Human studies have suggested that alterations in functions that are hormonally controlled such as duration of lactation, maintenance of pregnancy, and fertility may occur from DDT exposure. ... 

While the literature abounds with reports of the undesirable reproductive consequences of DDT exposure at all levels of animal systems, little human research in this area has made its way into the open literature. Shepard s Catalog of Teratogenic Agents (ref. 86) and Nisbet-Karch (ref. 47) each list only the work of O Leary et al. (ref. 87), correlating spontaneous abortion in human females with human pesticide residues, and prematurity of human fetuses with DDE levels found in fetal whole blood. Perhaps the more serious risk with DDT and DDE is the significant presence of these two along with other... 

Considering its relatively long history of widespread use, it is remarkable that epidemiological studies of cancer risk focused on DDT exposure are almost non-existent. Ditraglia et al (61) studied mortality in workers from four organochlorine pesticide manufacturing plants, one of which had solely manufactured DDT since 1947. Cohorts were defined as all workers who had been employed for at least six months prior to 1965 and vital status was ascertained up to 1976. For the DDT plant a total of 6 cancer deaths were found leading to the calculation of an SMR of... 

Maternal dichloro-diphenyl-trichloroethane (DDT) exposure before pregnancy may be involved in some cases of offspring ADHD.39... 

Hardell, L., Lindstrom, G., Van Bavel, B. (2002). Is DDT exposure during fetal period and breast-feeding associated with neurological impairment Environ. Res. 88 141—144. 

Makovskaya El, Burkatskaya EN, Voitenko GA (1962) On DDT exposure on animal s organism by inhalation. In Hygiene and Toxicology of New Pesticides and Clinical Features of Poisonings, Medgiz, Moscow, pp 262-268. 

Anonymous (1983). DDT exposures in a natural history museum in Colorado. Morbidity and Mortality Weekly Report, 32(34), 443-444. 

Parent substances and metaboHtes may be stored in tissues, such as fat, from which they continue to be released following cessation of exposure to the parent material. In this way, potentially toxic levels of a material or metaboHte may be maintained in the body. However, the relationship between uptake and release, and the quantitative aspects of partitioning, may be complex and vary between different materials. For example, volatile lipophilic materials are generally more rapidly cleared than nonvolatile substances, and the half-Hves may differ by orders of magnitude. This is exemplified by comparing halothane and DDT (see Anesthetics Insectcontholtechnology). 

Although eggshell thinning attributable to DDE exposure has occurred in birds in the UK, the lethal and siiblethal effects of the cyclodiene pesticides aldrin, dieldrin and heptachlor are also believed to have contributed to the population effects, particularly in the case of the sparrowhawk and peregrine falcon. Following the withdrawal of DDT and the cyclodienes from use in the UK, Europe and North America, bird of prey populations that were severely affected have shown partial or complete recovery. ... 

There is some evidence for chemically mediated endocrine disruption in amphibians. The egg yolk protein, vitellogenin, is inducible in amphibians by exposure to DDT. " Males of the short clawed toad Xenopus laevis given 250 fig/g or 1 fig/g o,p -DDT for seven days have been shown to produce vitellogenin, although the induction was less than that achieved by treatment with 1 fig/g of either 17/1-oestradiol or diethylstilboestrol. Research has also shown that endocrine disrupting chemicals can alter sex ratios in wild populations of certain species PCB congeners and organochlorine compounds have been linked with male domination of sex ratios in polluted compared to unpolluted sites. ... 

Many very hazardous solvents, such as benzene and carbon tetrachloride, were widely used until the 1970s. The situation was very similar for the use of pesticides. Among the toxic pesticides that were still in wide use 20 years ago were chlorophenols, DDT, lindane, and arsenic salts, all of which are classified as human carcinogens as well as being acutely toxic. Fortunately, use of these kinds of very toxic chemicals is now limited in the industrialized world. However, because the number of chemicals used in various industries continues to increase, the risks of long-term health hazards due to long-term exposure to low concentrations of chemicals continues to be a problem in the workplace. 

In a case-control study of pesticide factory workers in Brazil exposed to methyl parathion and formulating solvents, the incidence of chromosomal aberrations in lymphocytes was investigated (De Cassia Stocco et al. 1982). Though dichlorodiphenyltrichloroethane (DDT) was coformulated with methyl parathion, blood DDT levels in the methyl parathion-examined workers and "nonexposed" workers were not significantly different. These workers were presumably exposed to methyl parathion via both inhalation and dermal routes however, a dose level was not reported. The exposed workers showed blood cholinesterase depressions between 50 and 75%. However, the baseline blood cholinesterase levels in nonexposed workers were not reported. No increases in the percentage of lymphocytes with chromosome breaks were found in 15 of these workers who were exposed to methyl parathion from 1 week to up to 7 years as compared with controls. The controls consisted of 13 men who had not been occupationally exposed to any chemical and were of comparable age and socioeconomic level. This study is limited because of concomitant exposure to formulating solvents, the recent history of exposure for the workers was not reported, the selection of the control group was not described adequately, and the sample size was limited. 

Davy, F.B., Kleereko. H., and Matis, J.H. (1973). Effects of exposure to sublethal DDT on exploratory behavior of goldfish (Carassius auratus). Water Resources Research 9, 900-905. 

Hohn, L., Blomqvist, A., and Brandt, I. et al. (2006). Embryonic exposure to o,/ -DDT causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen. Environmental Toxicology and Chemistry 25, 2787-2793. 

Iwaniuk, A.N., Koperski, D.T., and Cheng, K.M. et al. (2006). The effects of enviromnental exposure to DDT on the brain of a songbird Changes in structures associated with mating and song. Behavioural Brain Research 173, 1-10. 

It is true that the degree of system damage may be determined in part by the nature of the exposure thus, in mammals, high concentrations of DDT may produce central nervous system stimulation and cardiac irregularities, while low concentrations, absorbed over a period of time, may produce damage primarily to parenchymal tissues (3). Generally, similar chemical types exert approximately similar qualitative physiologic... 

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