Chlordane toxicity

Saxena, S.C. and A.K. Karel. 1976. On effect of chlordane on the blood glucose and of glucose administration on the acute chlordane toxicity in Meriones hurrianae Jerdon, the Indian desert gerbil. Bull. Environ. Contam. Toxicol. 15 593-600. 

Qi-photochlordane was about 10 times less toxic to Daphnia pulex than di-chlordane (Podowski et al. 1979). This is in sharp contrast to the pattern shown in bluegill and goldhsh (Sudershan and Khan 1980). Further, di-photochlordane and di-chlordane toxicity to mice and houseflies was about the same (Podowski et al. 1979), which demonstrates the difficulty in generalizing about the comparative toxicity of chlordane isomers. 

Oral LD50 values for rats are reported at 100-220 mgkg while those for mice are 30-68 mg kg The toxic effects of heptachlor in animals are the same as those of chlordane. Chlordane toxicity in animals is similar to that of other organochlorine insecticides except tremor is absent. CNS involvement produces hyperexcitability and convulsions. 

The most sensitive indicators of acute chlordane toxicity in humans are central nervous system effects including headache, confusion, behavioral aberrations, and tremors (EPA 1980a Harrington et al. 1978). At high levels of exposure, central nervous system effects include convulsions, coma, respiratory failure, and eventually death. Effects on the liver appear to be the only manifestations in humans of chronic exposure to chlordane (EPA 1980a Ogata and Izushi 1991). 

Humans with chronic liver disease or impaired liver function may be unusually susceptible to chlordane toxicity. Infante et al. (1978) speculated on the existence of an unusually susceptible... 

Hyde KM, Falkenberg RL. 1976. Neuroelectrical disturbance as indicator of chronic chlordane toxicity. Toxicol AppI Pharmacol 37 499-515. 

Karel AK, Saxena SC. 1976. Chronic chlordane toxicity Effect on blood biochemistry of Meriones hurr/anae Jerdon, the Indian desert gerbil. Pestic Biochem Physiol 6 111-114. 

Toxic Effects on the Blood-Forming Tissues Reduced formation of erythrocytes and other elements of blood is an indication of damage to the bone marrow. Chemical compounds toxic to the bone marrow may cause pancytopenia, in which the levels of all elements of blood are reduced. Ionizing radiation, benzene, lindane, chlordane, arsenic, chloramphenicol, trinitrotoluene, gold salts, and phenylbutazone all induce pancytopenia. If the damage to the bone marrow is so severe that the production of blood elements is totally inhibited, the disease state is termed aplastic anemia. In the occupational environment, high concentrations of benzene can cause aplastic anemia. 

Experience in the baking industry since World War II has shown that proper use of residual spray materials such as DDT and chlordan will most effectively control these casual invaders. When housekeeping in a bakery is maintained as near perfect as possible, the application of a residual layer of toxic insecticide on areas upon which casual invaders are most likely to travel in seeking harborage will effectively kill the invader individual before it has an opportunity to nest. Experience has borne out this theory in a general way, and specific data are now being collected which will describe it in more scientific terms. 

Kearns, Weinman, and Decker rate the more common halogenated insect toxicants in the following order of decreasing toxicity (7) dieldrin, aldrin, heptachlor, 7-hexachloro-cyclohexane, chlordan, toxaphene, and DDT. This rating follows as the result of rather extensive tests on ten species of insects and is believed to represent, in general, the order of their relative activity. 

Studies on the control of various species of ants show conclusively that aldrin consistently gives control when applied to infested turf at the rate of 1 ounce per 1000 square feet (4 ounces of 25% wettable powder in 200 gallons of water). This dosage is only half of that required when chlordan is the toxicant employed (11,12). 

Aldrin, like chlordan, exhibits residual effectiveness under field conditions for somewhat less than 3 weeks. Even when aldrin is applied at the uneconomical and unnecessary rate of 5 pounds per acre, leafy material so treated exhibits only slight insect toxicity after 3 weeks. Aldrin, therefore, falls into that class of materials which exhibit pronounced initial toxicity but relatively short residual action. 

These compounds are much more toxic than chlordan (Table III), and yet are stable toward alkaline reagents (15), being unable to eliminate hydrogen chloride without the formation of a double bond at a bridgehead carbon atom. Thus in this type of compound the conclusion must again be reached that dehydrochlorination with alkali and insecticidal activity have no systematic relationship. 

The commonly used organic insect toxicants do not interfere in the analysis of Compound 118 by this new procedure. Hexane solutions of chlordan, DDT, methoxychlor, hexachlorocyclohexane (BHC), and toxaphene treated according to the procedure for determining Compound 118 gave a pale yellow color similar to that of the blank. 

It was previously shown (4) that the oral LD50 of chlordan in rats was 200 to 250 mg. per kg., in rabbits about 300 mg. per kg., and on intravenous injection in rabbits in Tween 20 about 20 mg. per kg. It was also shown (4) that the chronic toxicity of chlordan in both rats and rabbits was greater than that of DDT under comparable conditions. 

The conversion in the animal body of at least some of the water-insoluble chlordan to a water-soluble degradation product must facilitate the elimination of the poison through its excretion into the urine by the kidneys. Moreover, the degradation of chlordan as shown in the present experiments may be a mechanism for its detoxification, as in the case of DDT (1). Only the isolation of the degradation product, its identification, and a study of its toxicity can determine this point. 

As Muller had prophesied and indeed hoped, DDT stimulated the discovery of more synthetic insecticides. DDT relatives included chlordane, toxaphene, aldrin, dieldrin, endrin, and heptachlor. Popular substitutes for DDT s family included organophosphates such as parathion, which is a powerful neurotoxin, and carbamates, which are also highly toxic to people. Unlike DDT, parathion and aldicarb have killed and injured many farm workers. Malathion was later developed to be several hundred times less toxic than parathion. 

Overall, insecticides seriously affect invertebrates in the soil, especially insects, but affect microorganisms much less [3,6]. The most toxic OCPs for soil invertebrates are heptachlor and chlordan. They sharply decrease the numbers of almost all invertebrate groups, including insects, earthworms, and ticks [6]. 

Chlordane produced before 1951 contained a significant quantity of hexachlorocyclopentadiene — a toxic irritant to warm-blooded animals. Chlordane produced since 1951 contains little or none of this compound (Ingle 1965). A high-purity chlordane formulation containing about 74% cis-chlordane and 24% fims-chlordane is also available (Nomeir and Hajjar 1987). 

Chlordane-induced mortality of the long-billed curlew (Numenius americanus) has been documented at least four times since 1978, despite restriction of technical chlordane use since 1980 to subterranean applications for termite control (Blus et al. 1985). Death of these curlews was probably due to over-winter accumulations of oxychlordane of 1.5 to 5.0 mg/kg brain FW and of heptachlor epoxide at 3.4 to 8.3 mg/kg — joint lethal ranges for oxychlordane and heptachlor epoxide in experimental birds — compared to 6 mg/kg brain for oxychlordane alone and 9 mg/kg for heptachlor epoxide alone (Blus et al. 1985). Additional research is needed on toxic interactions of chlordane components with each other and with other chemicals in the same environment. 

Concern for the continued widespread use of chlordane centers on its ability to cause liver cancer in domestic mice. Other adverse effects in mammals, such as elevated tissue residues and growth inhibition, were frequently associated with diets containing between 0.76 and 5.0 mg chlordane/kg feed. Metabolism of technical chlordane by mammals results primarily in oxychlordane, a metabolite that is about 20 times more toxic than the parent compound and the most persistent metabolite stored in adipose tissues. Chlordane interactions with other agricultural chemicals produced significant biological effects in warm-blooded organisms, indicating a need for additional research on this subject. 

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