[QUOTE=MoskTheDissenter]
I
Again, there is scientific doubt. No one has provided any scientific study that shows otherwise. Saying it’s “common knowlege” or that “there is no doubt” is wrong, unscientific, and valueless in determining the truth. As I mentioned way back, there hasn’t been clear evidence of severge ecological effects. Aside from the 3 main (and somewhat flawed) studies the anti-DDT group depends on (that I mentioned above), there hasn’t been any conclusive evidence.
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Wiki:
*Environmental impact
DDT is a persistent organic pollutant with a half life of between 2-15 years, and is immobile in most soils. Its half life is 56 days in lake water and approximately 28 days in river water. Routes of loss and degradation include runoff, volatilization, photolysis and biodegradation (aerobic and anaerobic). These processes generally occur slowly. Breakdown products in the soil environment are DDE (1,1-dichloro-2,2-bis(p-dichlorodiphenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane), which are also highly persistent and have similar chemical and physical properties.[23] These products together are known as total DDT.
DDT and its metabolic products DDE and DDD magnify through the food chain, with apex predators such as raptors having a higher concentration of the chemicals (stored mainly in body fat) than other animals sharing the same environment. In the United States, human blood and fat tissue samples collected in the early 1970s showed detectable levels in all samples. A later study of blood samples collected in the later half of the 1970s (after the U.S. DDT ban) showed that blood levels were declining further, but DDT or metabolites were still seen in a very high proportion of the samples. Biomonitoring conducted by the CDC as recently as 2002 shows that more than half of subjects tested had detectable levels of DDT or metabolites in their blood,[24] and of the 700+ milk samples tested by the USDA in 2005, 85% had detectable levels of DDE.[25]
DDT is a toxicant across a certain range of phyla. In particular, DDT is a major reason for the decline of the bald eagle in the 1950s and 1960s[26][27] as well as the peregrine falcon. DDT and its breakdown products are toxic to embryos and can disrupt calcium absorption thereby impairing egg-shell quality.[28] Studies in the 1960s and 1970s failed to find a mechanism for the hypothesized thinning,[29] however more recent studies in the 1990s and 2000s have laid the blame at the feet of DDE,[30][31] but not all experts accept those claims.[citation needed] Some studies have shown that although DDE levels have fallen dramatically that eggshell thinness remains 10–12 percent thinner than pre-DDT thicknesses.[32] In general, however, DDT in small quantities has very little effect on birds; its primary metabolite, DDE, has a much greater effect.[citation needed] DDT is also highly toxic to aquatic life, including crayfish, daphnids, sea shrimp and many species of fish. DDT may be moderately toxic to some amphibian species, especially in the larval stages. In addition to acute toxic effects, DDT may bioaccumulate significantly in fish and other aquatic species, leading to long-term exposure to high concentrations.*
…
*Cancer
* The EPA, in 1987 , classified DDT as class B2, a probable human carcinogen based on "Observation of tumors (generally of the liver) in seven studies in various mouse strains and three studies in rats. DDT is structurally similar to other probable carcinogens, such as DDD and DDE." Regarding the Human Carcinogenicity Data, they stated "The existing epidemiological data are inadequate. Autopsy studies relating tissue levels of DDT to cancer incidence have yielded conflicting results. Three studies reported that tissue levels of DDT and DDE were higher in cancer victims than in those dying of other diseases (Casarett et al., 1968; Dacre and Jennings, 1970; Wasserman et al., 1976). In other studies no such relationship was seen (Maier-Bode, 1960; Robinson et al., 1965; Hoffman et al., 1967). Studies of occupationally exposed workers and volunteers have been of insufficient duration to be useful in assessment of the carcinogenicity of DDT to humans."[39]
* A study of malaria workers who handed DDT occupationally found an elevated risk of cancers of the liver and biliary tract. Another study has found a correlation between DDE and liver cancer in white men, but not for women or black men. An association between DDT exposure pancreatic cancer has been demonstrated in a few studies, but other studies have have found no association. Several studies have looked for associations between DDT and multiple myeloma, and testicular, prostate, endometrial, and colorectal cancers, but none conclusively demonstrated any association.[40]
[edit] Breast cancer
* The journal Cancer recently published a review of all of the epidemiological studies on breast cancer and DDT and DDE published between 2000 and 2006. The authors state that "Positive findings for well-controlled studies in the early 1990s of associations between breast cancer risk and the insecticide DDT, its breakdown product DDE, and PCBs prompted additional study. Snedeker reviewed studies of DDT/DDE and dieldrin, concluding that existing research strategies provided conflicting and mostly negative evidence…Updating the picture to 2006 provides…essentially unchanged conclusions for DDT/DDE." Turning their attention to the recent studies, they conclude that "A few studies show elevated risk," but "[m]ost studies did not support an association of DDE and breast cancer overall or stratified by menopausal status, tumor hormone receptor status, parity, breast-feeding, or body mass index…*n light of these findings, additional study of incident breast cancer in association with biological measures of DDE/DDT levels near the time of diagnosis is not a promising avenue."[41]
* Some direct studies have not found a link between DDT and breast cancer in humans,[42] while others suggests a link between DDT and breast cancer in humans. For example, diminishing rates of breast cancer in Israel have paralleled a precipitous decline in environmental contamination with DDT and benzene hexachloride.[43][44][45][46]
* Dr. Mary Wolf published a 1993 article in the Journal of the National Cancer Institute indicating a statistically significant correlation between DDT metabolites in the blood and the risks of developing breast cancer in the general population.[47] Others have disputed this research.[citation needed]
* A study of 692 women, half of them control subjects, over a period of twenty years established no correlation between serum DDE and breast cancer. DDE is a metabolite of DDT, and correlates with DDT exposure.[48]
* According to a 2005 review in The Lancet, "**reast cancer has been examined most closely for an association with p, p'-DDE. In a study in 1993, 37 breast cancer patients had higher serum DDE concentrations (11.8 μg/L) than controls (7.7 μg/L), and results from several subsequent studies supported such an association. However, large epidemiological studies and subsequent pooled and meta-analyses failed to confirm the association."[40]
[edit] Developmental and reproductive toxicity
DDT and its breakdown product DDE, like other organochlorines, have been shown to have xenoestrogenic activity; meaning it is chemically similar enough to estrogen to trigger hormonal responses in contaminated animals. This hormonal-mimicking activity has been observed when DDT is used in laboratory studies involving mice and rats as test subjects, and available epidemiological evidence indicates that these effects may be occurring in humans as a result of DDT exposure.
* Human epidemiological studies suggest that DDT exposure is a risk factor for premature brith and low birth weight, and may harm a mother's ability to breast feed. Some researchers argue that these effects may cause increases infant deaths in areas where DDT is used for malaria control, and thus offset any benefit derived from its anti-malarial effects.[49][50]
* Several recent studies demonstrate a linke between in utero exposure to DDT or DDE and developmental neurotoxicity in humans. For example, a 2006 study conducted by the University of California, Berkeley suggests children who have been exposed to DDT while in the womb have a greater chance of experiencing development problems,[51] and another study from the same year found that even low-level concentrations of DDT in serum from the umbilical cord at birth were associated with a decrease in cognitive skills at 4 years of age.[52] Similarly, Mexican researchers have demonstrated a link between DDE exposure in the first trimester of pregnancy and retarted psychomotor development.[53]
* A review article[40] in The Lancet concludes:
Although DDT is generally not toxic to human beings and was banned mainly for ecological reasons, subsequent research has shown that exposure to DDT at amounts that would be needed in malaria control might cause preterm birth and early weaning, abrogating the benefit of reducing infant mortality from malaria...DDT might be useful in controlling malaria, but the evidence of its adverse effects on human health needs appropriate research on whether it achieves a favourable balance of risk versus benefit.
Future perspectives: 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 public-health intervention that is cheap, longlasting, and effective. However, various toxic-effects that would be difficult to detect without specific study might exist and could result in substantial morbidity or mortality. Responsible use of DDT should include research programmes that would detect the most plausible forms of toxic effects as well as the documentation of benefits attributable specifically to DDT. Although this viewpoint amounts to a platitude if applied to malaria research in Africa, the research question here could be sufficiently focused and compelling, so that governments and funding agencies recognise the need to include research on all infant mortality when DDT is to be used.
* A 2007 study documented decreases in semen quality among South African men from communities where DDT is used to combat endemic malaria. The researchers found statistically significant correlations between increased levels of DDT or DDE in blood plasma and decreases in several measures of semen quality including ejaculate volume, certain motility parameters, and sperm count.[54] The same researchers reported similar results in 2006 from a study of men in Mexico.[55] A review of earlier studies noted that "Studies of populations with a much lower exposure than that seen in current malaria-endemic areas have shown only weak, inconsistent associations between DDE and testosterone amounts, semen quality, and sperm DNA damage."[40]
You may follow the footnotes to get to the studies.
I know the USA etc would not pay for DDT, but that is not the same* as not allowing other nations to use it. *