We did a search of PubMed from the mid-1960s to February, 2005, for the use, body burden, and toxic and health effects of DDT. We used the keywords “DDT” and “DDE” and any of “malaria”, “mosquito”, “drug resistance”, “toxicity”, “health”, “cancer”, “reproduction”, “oestrogen”, “neurological”, and “development”. Of 3650 reports published on DDT, we gave preference to studies in the past 5 years on human health effects of DDT.
ReviewHealth risks and benefits of bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT)
Section snippets
DDT exposure and concentration in human tissues
Technical-grade DDT contains 65–80% p,p′-DDT, 15–21% o,p′-DDT, and up to 4% p,p′-DDD (bis[4-chlorophenyl]-1,1,-dichloroethane).2 When sprayed, DDT can drift, sometimes for long distances. In the soil, the compound can evaporate or attach to wind-blown dust. In the environment, DDT breaks down to p,p′-DDE (bis[4-chlorophenyl]-1,1-dichloroethene),1 an extremely stable compound that resists further environmental breakdown or metabolism by organisms. DDE is the form usually found in human tissue in
Toxic effects of DDT
Toxic effects of DDT and its analogues have been extensively studied in laboratory animals. Acute exposure to a high dose of DDT can cause death.12 Exposure to DDT or DDE increases liver weight, induces liver cytochrome P450 (CYP) 2B and 3A and aromatase,21, 22, 23 and causes hepatic-cell hypertrophy and necrosis.12 DDT is insecticidal because of its neurological toxic effects. In laboratory animals, DDT causes hyperactivity, tremor, and seizures. DDT is carcinogenic in mice and rats, mainly
Neurobehaviour
DDT poisoning usually results in paresthesia, dizziness, headache, tremor, confusion, and fatigue.12 Occupational exposure to DDT was associated with reduced verbal attention, visuomotor speed, sequencing, and with increased neuropsychological and psychiatric symptoms in a dose-response pattern (ie, per year of DDT application) in retired workers aged 55–70 years in Costa Rica.32 Although DDT or DDE concentrations were not determined in this study, they probably were very high. People who
Cancer
Although extensively studied, there is no convincing evidence that DDT or its metabolite DDE increase human cancer risk. Mainly on the basis of animal data, DDT is classified as a possible carcinogen (class 2B) by the International Agency for Research on Cancer (IARC)35 and as a reasonably anticipated human carcinogen by the US National Toxicology Program.36
Breast cancer has been examined most closely for an association with p,p′-DDE. In a study in 1993,37 breast cancer patients had higher
Reproductive health
Various reproductive and hormonal endpoints have been examined in both men and women, and although associations have been recorded, causal links have not been confirmed. In Chiapas, Mexico, where DDT was sprayed for malaria control, serum p,p′-DDE concentrations were inversely correlated with semen volume, sperm count, and bioavailable-to-total testosterone ratios in 24 young men not occupationally exposed to DDT.75 However, results from another study of South African malaria workers did not
Infant and child development
Although infant and child growth and neurodevelopment have been studied, no study has been large enough to show an effect on infant and child survival. In a German study,117 girls with the highest quartile of DDE concentration (>0·44 μg/L whole blood) were an average of 1·8 cm shorter at age 8 years than girls with the lowest quartile of DDE; the difference narrowed at age 9 years and disappeared at age 10 years. However, no such effect was seen in boys. Another study did not show any
Immunology and DNA damage
Increased plasma concentrations of DDE were associated with raised IgA in one study126 and with reduced IgG in another.127 Plasma p,p′-DDE was inversely associated with in-vitro secretion of tumour necrosis factor (TNF) α by umbilical cord-blood mononuclear cells.128 Do these effects translate into immunological disorders with clinical consequences? One study suggested that raised prenatal exposure of p,p′-DDE increased the risk of otitis media in Inuit infants,129 but this association was not
Efficacy and effectiveness of DDT for malaria control
Convincing historical evidence has shown that indoor residual house-spraying with DDT was the main method by which malaria was eradicated or greatly reduced in many countries worldwide in the 1940s to 1960s. However, these programmes had not been aimed to rigorously investigate the efficacy of individual components nor of local factors that might modify their effects. In sub-Saharan Africa, early pilot projects of malaria eradication also showed that the disease is highly responsive to vector
Debate and decision-making
Since evidence now indicates that DDT might have adverse effects on human health, it is prudent to consider currently available evidence of benefits and possible risks of DDT use in the context of modern malaria control. Infants are generally known to bear the burden of mortality from malaria worldwide (figure 3);138 most such mortality occurs in the first 5 years of life and in areas south of the Sahara (figure 4).139 The decision to use DDT would be straightforward if we had data from trials
Benefits of DDT spraying in sub-Saharan Africa
The success of the Malaria Eradication Campaign in 1955–69 was attributed to DDT.1 However, these programmes often included other components, such as provision of basic medical care, and were not designed to allow investigation of their individual parts. Thus, Giglioli140 showed large improvements in infant and all-cause mortality during three decades for employees of the sugar plantations in South America, but the quantitative role of DDT is impossible to specify. Without the appropriate
Risks of DDT spraying in sub-Saharan Africa
For indoor residual spraying to effectively prevent infant mortality from malaria, women of child-bearing age, pregnant women, and breastfeeding women will need to be exposed to DDT. Such spraying might be without the ecological effects that caused the ban (although more data are needed), but will unavoidably expose women to amounts of DDT that are associated with forms of toxic effects that might increase infant mortality. Of adverse effects to human health, reproductive outcomes are the major
Balance of benefits and risks from DDT use in malaria control
Malaria remains a difficult problem in Africa. Indoor residual spraying of DDT could be effective in some settings; the procedure is unlikely to lift the entire malaria mortality burden in infants and children. Additionally, if continuous DDT spraying does cause increased preterm births and shortened breastfeeding duration, infant deaths will occur, perhaps to the same extent as the deaths spraying would potentially prevent. Mothers would also carry a body burden of DDT, and even if they were
Future perspectives
DDT was originally banned because of ecological effects, such as eggshell thinning, and accumulation in the environment and organisms, including human beings. Although acute toxic effects are scarce, toxicological evidence shows endocrine-disrupting properties; human data also indicate possible disruption in semen quality, menstruation, gestational length, and duration of lactation. The research focus on human reproduction and development seems to be appropriate. DDT could be an effective
Search strategy and selection criteria
References (148)
- et al.
DDT house spraying and re-emerging malaria
Lancet
(2000) - et al.
Should DDT be banned by international treaty?
Parasitol Today
(2000) DDT and its analogs
- et al.
Levels of dichlorodiphenyltrichloroethane and deltamethrin in humans and environmental samples in malarious areas of Mexico
Environ Res
(2002) - et al.
Induction of hepatic aromatase by p,p′-DDE in adult male rats
Mol Cell Endocrinol
(2001) - et al.
Development and standardization of a simple binding assay for the detection of compounds with affinity for the androgen receptor
Toxicology
(2004) - et al.
Chemical exposure of embryos during the preimplantation stages of pregnancy: mortality rate and intrauterine development
Am J Obstet Gynecol
(1984) - et al.
Chronic nervous-system effects of long-term occupational exposure to DDT
Lancet
(2001) - et al.
Motor function in aging Great Lakes fisheaters
Environ Res
(1999) - et al.
Serum concentrations of organochlorine compounds and K-ras mutations in exocrine pancreatic cancer
Lancet
(1999)
A nested case-control study of non-Hodgkin lymphoma and serum organochlorine residues
Lancet
Adipose tissue concentrations of p,p′-DDE and the risk for endometrial cancer
Gynecol Oncol
The hormonal effects of long-term DDT exposure on malaria vector-control workers in Limpopo Province, South Africa
Environ Res
The long-term effects of DDT exposure on semen, fertility, and sexual function of malaria vector-control workers in Limpopo Province, South Africa
Environ Res
DDT and DDE exposure in mothers and time to pregnancy in daughters
Lancet
Reproductive outcomes in DDT applicators
Environ Res
Maternal serum level of the DDT metabolite DDE in relation to fetal loss in previous pregnancies
Environ Res
Association of DDT with spontaneous abortion: a case-control study
Ann Epidemiol
Serum levels of polychlorinated biphenyls and some organochlorine insecticides in women with recent and former missed abortions
Environ Res
Spontaneous abortion and human pesticide residues of DDT and DDE
Am J Obstet Gynecol
PCB and other organochlorine compounds in blood of women with or without miscarriage: a hypothesis of correlation
Ecotoxicol Environ Saf
Association between maternal serum concentration of the DDT metabolite DDE and preterm and small-for-gestational-age babies at birth
Lancet
DDT and its derivatives. Environmental health criteria 9
Toxicological profile for DDT/DDD/DDE (update): US Department of Health and Human Services. Public Health Service
Dichlorodiphenyltrichloroethane (DDT): ubiquity, persistence, and risks
Environ Health Perspect
Commentary: malaria control in the 1990s
Bull World Health Organ
Banned and non-authorised pesticides in the United Kingdom
Decrease in eggshell weight in certain birds of prey
Nature
Ethical debate: doctoring malaria, badly: the global campaign to ban DDT
BMJ
DDT & malaria: answer to common questions
UN Environment Programme. Stockholm Convention on Persistent Organic Pollutants (POPs)
Risk of breast cancer and organochlorine exposure
Cancer Epidemiol Biomarkers Prev
Global surveillance of DDT and DDE levels in human tissues
Int J Occup Med Environ Health
Worldwide trends in DDT levels in human breast milk
Int J Epidemiol
Organochlorine pesticide levels in maternal adipose tissue, maternal blood serum, umbilical blood serum, and milk from inhabitants of Veracruz, Mexico
Arch Environ Contam Toxicol
Levels of DDT and metabolites in breast milk from Kwa-Zulu mothers after DDT application for malaria control
Bull World Health Organ
Malaria control and levels of DDT in serum of two populations in Kwazulu
J Toxicol Environ Health
Exposure assessment for workers applying DDT to control malaria in Veracruz, Mexico
Environ Health Perspect
Induction of the hepatic CYP2B and CYP3A enzymes by the proestrogenic pesticide methoxychlor and by DDT in the rat. Effects on methoxychlor metabolism
J Biochem Toxicol
Sex-dependent regulation of hepatic cytochrome P-450 by DDT
Toxicol Sci
Bioassay of DDT, TDE, p,p′-DDE for possible carcinogencity. Carcinogenesis technical report series. no 131
Effects of long-term oral administration of DDT on nonhuman primates
J Cancer Res Clin Oncol
Comparison of short-term estrogenicity tests for identification of hormone-disrupting chemicals
Environ Health Perspect
Persistent DDT metabolite p,p′-DDE is a potent androgen receptor antagonist
Nature
Sub-chronic effect of DDT on humoral immune response to a thymus-independent antigen (bacterial lipopolysaccharide) in mice
Bull Environ Contam Toxicol
Effects of sub-chronic DDT exposure on humoral and cell-mediated immune responses in albino rats
Bull Environ Contam Toxicol
Impairments of memory and learning in older adults exposed to polychlorinated biphenyls via consumption of Great Lakes fish
Environ Health Perspect
Report on carcinogens. 10th edn.
Blood levels of organochlorine residues and risk of breast cancer
J Natl Cancer Inst
Cited by (234)
DDT and titanium dioxide nanoparticle coexposure induced neurobehavioral deficits in zebrafish
2024, Neurotoxicology and TeratologyDDT exposure induces tremor-like behavior and neurotoxicity in developmental stages of embryonic zebrafish
2024, Ecotoxicology and Environmental SafetyWhat is the impact of the environment on breast cancer metastatic progression?
2023, Bulletin de l'Academie Nationale de MedecineContaminant containment for sustainable remediation of persistent contaminants in soil and groundwater
2023, Journal of Hazardous MaterialsMaternal pesticide exposure and risk of preterm birth: A systematic review and meta-analysis
2023, Environment International