Pesticide profiles : Toxicity, environmental impact and fate - Chapter 6 doc

© 2000 CRC Press LLC chapter six Chlorinated hydrocarbons 6.1Class overview and general description Background Chlorinated hydrocarbons, also known as organochlorines, were used widely from the 1940s to the 1960s for agricultural pest control and for malarial control programs. Since the 1960s their use in the U.S. has been curtailed greatly because of their persis- tence in the environment, in wildlife, and in humans. The pesticide most responsible for this reduction was dichlorodiphenyltrichloroethane (DDT). DDT use has been eliminated in the U.S. though it is still applied in many regions throughout the world. The organochlorines can be divided into three groups: 1) dichlorodiphenyl- ethanes (DDT and related compounds) (Figure 6.1A), 2) cyclodiene compounds (Figure 6.1B), and 3) other related compounds. In addition, particular organochlo- rines may consist of a number of related compounds. For example, toxaphene is made up of more than 177 related compounds. Although there is no structure common to all organochlorines, they are all charac- terized by one or more chlorine atoms positioned around one or more hydrocarbon rings. Members of each group of organochlorines share similar or identical composi- tions although they may have very different three-dimensional structures and shapes. These isomers may differ significantly in their toxicities and other characteristics. The generic structures of dichlorophenyl ethanes and cyclodienes are shown in Figures 6.1A and 6.1B, respectively. The latter is a member of the cyclodiene group. Dichlorophe- nylethanes, cyclodienes, and other chlorinated hydrocarbons are listed in Table 6.1. Chlorinated hydrocarbon usage Organochlorines are powerful pesticides, and members of this group can be produced at relatively low cost. At one time, DDT sold to the World Health Orga- nization (WHO) cost less than $0.22 per pound. DDT use reached a peak in 1961 when 160 million pounds were manufactured; 80% of that volume was used for agriculture. The other organochlorines also saw a great upsurge in use following World War II. Many of the commercially viable products, especially the cyclodienes such as aldrin, dieldrin, and heptachlor, were developed in the 1950s. Lindane, also known as BHC, is an expensive compound to produce and is thus reserved for nonagricultural uses such as louse and mite control lotions. When chlorinated hydrocarbon usage diminished in the 1960s and 1970s, they were replaced by the organophosphates (OPs) despite the higher mammalian acute toxicities of the OPs (1). Organochlorines still in use in the U.S. are utilized to protect a variety of crops and ornamental flowers, as well as to control house pests. © 2000 CRC Press LLC Mechanism of action and toxicology Mechanism of action The chlorinated hydrocarbons are stimulants of the nervous system. Their mode of action is similar in insects and humans. They affect nerve fibers, along the length of the fiber, by disturbing the transmission of the nerve impulse. More specifically, the members of this group of pesticides disrupt the sodium/potassium balance that surrounds the nerve fiber. The result of this imbalance is a nerve that sends trans- missions continuously rather than in response to stimuli. Despite the similarity of many of the compounds within each of the three sub- groups, the individual toxicities vary greatly (2). The compounds also vary greatly in their ability to be stored in tissue. For example, the structure of methoxychlor is very similar to DDT, but its toxicity is far lower, as is its tendency to accumulate in fatty tissue. Storage in fatty tissue is a strategy that the body uses to remove toxic materials from active circulation. Fatty storage prevents the toxic agent from reaching AB Figure 6.1 Structures of generic cyclodienes (A) and dichlorophenylethanes (B). Table 6.1 Chlorinated Hydrocarbons Dichlorophenylethanes Chlorobenzilate* DDT Dicofol* Methoxychlor* Cyclodienes and related compounds Aldrin Chlordane* Dieldrin Endosulfan* Endrin Heptachlor* Toxaphene Other chlorinated hydrocarbons Chlorothalonil* Dalapon Dienochlor Hexachlorobenzene (HCB)* Lindane* Mirex PCNB (Quintozene)* Pentachlorophenol* Note: * indicates that a profile for this com- pound is included in this chapter. © 2000 CRC Press LLC the target organ until it is remobilized in an organism, generally through metabolism of fat. The toxicity of organochlorines, DDT in particular, is directly related to their concentration in nerve tissue. Acute and chronic effects are rapidly reversible when the concentration falls below some threshold level. The threshold levels vary with each compound. The abatement of symptoms, however, does not necessarily mean that the pesticide has been removed from the body, but rather that the compound has been removed from active circulation in the body (2). Acute toxicity Although each of the three subgroups of the chlorinated hydrocarbon com- pounds have rather distinctive sets of symptoms, they, as a class, mainly affect the central nervous system, and the symptoms of poisoning are muscular and behavioral effects. The most common symptom across the entire range of organochlorines is nervousness and hyperexcitement leading to tremors (3). The tremors may progress gradually to the point of convulsions. Some organochlorines, however, cause con- vulsions immediately after exposure (2). These pesticides may be responsible for the onset of fever, although the specific reasons for the fever are currently unclear. It may be due to the direct poisoning of the temperature-control center in the brain, or the body’s inability to rapidly get rid of heat generated by a convulsion, or other causes. Other symptoms of organochlorine poisoning include vomiting, nausea, confusion, and uncoordinated movement (2). Chronic toxicity Reproductive effects Organochlorine compounds may adversely affect fertility and reproduction at high doses. In a 3-week dietary mouse study of chlordane, fertility was reduced by about 50% at a dose of 22 mg/kg/day (4). In another study, rat offspring only experienced adverse effects when the doses, 6.25 and 12.5 mg/kg/day dicofol, were high enough to cause maternal toxicity (5). At doses up to 100 mg/kg/day of another organochlorine, chlorobenzilate, there were no adverse reproductive effects in rats (6). It is unlikely that organochlorine compounds will cause reproductive effects in humans at expected exposure levels. Teratogenic effects Most of the animal studies with organochlorine compounds have shown that there were no teratogenic effects (2). However, two of the organochlorine com- pounds, hexachlorobenzene (HCB) and dieldrin, have been shown to cause birth defects at high doses. In a rat study with HCB, some offspring had an extra rib and cleft palates (7). In a dietary study of dieldrin, mice experienced delayed bone formation and an increase in rib bones (2). Based on all of the evidence, organochlorine compounds are unlikely to produce teratogenic effects in humans. Mutagenic effects In studies of nearly all of the commonly used organochlorine compounds, no mutagenic effects were found. The only exception was endosulfan, which was found to be mutagenic to bacterial and yeast cells (2). © 2000 CRC Press LLC Carcinogenic effects In several chronic, high-dose exposure rat studies with organochlorine com- pounds such as chlordane, heptachlor, and pentachlorophenol, there were increased incidences of liver tumors. Because the above compounds have caused liver tumors in rats, they have been classified by the U.S. EPA as probable human carcinogens (8). Ecological effects Effect on birds Organochlorine compounds are only slightly acutely toxic to birds. For example, the LD 50 dose of lindane in bobwhite quail is 120 to 130 mg/kg (9). The LC 50 value for DDT is 611 ppm in bobwhite quail, 311 ppm in pheasant, and 1869 ppm in mallard duck (10). The evidence of bioaccumulation is most notable at the top of the food chain in the terrestrial community. Predatory birds contain the highest body burdens and thus suffer the most effects, generally reproductive failure. DDT and the other orga- nochlorines can cause reproductive failure by disrupting the bird’s ability to mobilize calcium, thus resulting in thin, brittle eggshells that may be crushed by the parents during incubation or attacked by bacteria (10). Effects on aquatic organisms The acute toxicity of organochlorine compounds to aquatic life varies but may be very high. For example, the LC 50 value for toxaphene is <0.001 mg/L in freshwater fish. However, the LC 50 value for lindane is 0.1 mg/L in freshwater fish (11). The evidence of bioaccumulation is most notable at the top of the food chain in the aquatic community. Predatory fish contain the highest body burdens and thus suffer the most from reproductive failure. Fish reproduction can be affected when organochlorines, such as DDT, concentrate in the egg sac. At a DDT residue level of 2.4 mg/kg, eggs of the winter flounder contained abnormal embryos in the labora- tory (10). Effects on other organisms (non-target species) Organochlorine compounds range from highly toxic to nontoxic to bees. Com- pounds such as chlordane and lindane are highly toxic, while dicofol and HCB are nontoxic to bees (9). Environmental fate Breakdown in soil and groundwater Organochlorines are not mobile in soil because they are tightly bound to soil particles and do not dissolve in water. Some localized or regional movement of chlorinated hydrocarbon compounds may occur while attached to soil particles, either through the blowing of dust and soil or through soil erosion. Because orga- nochlorine compounds bind tightly to soil, they resist leaching into the groundwater (12). Of particular significance is the ability of organochlorines to persist for long periods in the environment in biologically active forms and to accumulate in living systems. © 2000 CRC Press LLC Most notable within this group of long-lasting insecticides are DDT and dieldrin. The average time it takes for half of a chlorinated hydrocarbon compound to disappear after it is applied to soil is between 2 and 10 years (13–15). For a compound with a half-life of 10 years, over 12% of the compound would remain after a 30-year period. The compound’s resistance to biochemical degradation, coupled with its solubility in fats (lipids), leads to bioaccumulation in living organisms (12). Breakdown in water Most organochlorine compounds are insoluble in water (9) or dissolve very slowly in water. Methoxychlor has been detected at the Niagara River in New York at a very low concentration of 0.001 µ g/L (12). Therefore, it is more likely that organochlorines will be found in the sediment. Breakdown in vegetation Organochlorines may accumulate in fruits and vegetables. For example, chlo- robenzilate residues have been found in the peels of citrus fruits (16). When chlo- robenzilate was sprayed on treated crops, it caused the browning of the edges and veins of leaves (17). Worldwide dispersion Recent evidence points to organochlorine movement throughout the world. Organochlorine compounds like DDT and toxaphene, while banned for use in the U.S., are still being used in other parts of the world. These compounds slowly evaporate and are translocated throughout the world by wind and rain. For example, toxaphene, prior to its ban in 1982, was used in the southern U.S. on a variety of crops. Even though it was not used in the northern U.S., it has been found as a widespread contaminant throughout the Great Lakes region and in marine fish (18). Also, cyclodiene insecticides, such as chlordane, have been found in rainwater and organisms in Scandinavia though they have never been used in that area (19). Earlier notions about these pesticides remaining on or very near their application site have been revised as the result of recent studies. The physical and chemical properties of the organochlorines have led to their worldwide dispersion in the environment. 6.2Individual profiles 6.2.1 Chlordane Figure 6.2 Chlordane. © 2000 CRC Press LLC Trade or other names In addition to chlordane, common names have included chlordan and clordano. Trade names include Belt, Chlor Kil, Chlortox, Corodane, Gold Crest C-100, Kilex Lindane, Kypchlor, Niran, Octachlor, Synklor, Termex, Topiclor 20, Toxichlor, and Velsicol 1068. Regulatory status Because of concern about the risk of cancer, use of chlordane was canceled in April 1988. Between 1983 and 1988, the only permitted use for chlordane was for control of subterranean termites. Chlordane is no longer distributed in the U.S. The only commercial use still permitted is for fire ant control in power transformers. It was classified toxicity class II — moderately toxic. Products containing chlordane bear the Signal Word WARNING. Introduction Chlordane is a persistent organochlorine insecticide. It kills insects when ingested and on contact. Formulations include dusts, emulsifiable concentrates, gran- ules, oil solutions, and wettable powders. Toxicological effects Acute toxicity Chlordane is moderately to highly toxic through all routes of exposure. Symp- toms usually start within 45 minutes to several hours after exposure to a toxic dose. Convulsions may be the first sign of poisoning or they may be preceded by nausea, vomiting, and gut pain. Initially, poisoning victims may appear agitated or excited, but later they may become depressed, uncoordinated, tired, or confused. Other symptoms reported in cases of chlordane poisoning include headaches, dizziness, vision problems, irritability, weakness, or muscle twitching. In severe cases, respira- tory failure and death may occur. Complete recovery from a toxic exposure to chlordane is possible if proper medical treatment is administered (2,20). Chlordane is very irritating to the skin and eyes (21,22). Chlordane affects liver function; thus, many interactions between medicines and this pesticide may occur. Among these are decreased effectiveness of anticoagulants, phenylbutazone, chlorpromazine, steroids, birth control pills, and diphenhydramine. Increased activity of thyroid hormone may also occur (23). The oral LD 50 for chlordane in rats is 200 to 700 mg/kg, in mice is 145 to 430 mg/kg, in rabbits is 20 to 300 mg/kg, and in hamsters is 1720 mg/kg (2,9). The dermal LD 50 in rabbits is 780 mg/kg, and in rats is 530 to 690 mg/kg (9,17). The 4- hour inhalation LD 50 in cats is 100 mg/L (17,24). Chronic toxicity Liver lesions and changes in blood serum occurred in rats exposed to 1.0 mg/L chlordane in air. Increased kidney weights occurred in rats exposed to 10 mg/L. For monkeys, increased liver weight occurred at 10 mg/L (20). Animal studies have shown that consumption of chlordane caused damage to the liver and the central nervous system (20,21). In a 2-year feeding study with rats, © 2000 CRC Press LLC a near-lethal dose of 300 mg/kg/day produced eye and nose hemorrhaging, severe changes in the tissues of the liver, kidney, heart, lungs, adrenal gland, and spleen. In this same study, no adverse effects were observed in rats fed 5 mg/kg/day. In a long-term feeding study with mice, body weight loss, increased liver weight, and death occurred at doses of 22 to 63.8 mg/kg/day. Dogs fed doses of 15 and 30 mg/kg/day exhibited increased liver weights (2,20). Reproductive effects Chlordane has been shown to affect reproduction in test animals. Fertility was reduced by about 50% in mice injected with chlordane at 22 mg/kg once a week for 3 weeks (25). The data suggest that reproductive effects in humans are unlikely at expected exposure levels. Teratogenic effects No teratogenic effects were observed in rats born to dams fed chlordane at 5 to 300 mg/kg/day for 2 years (20). It is unlikely that chlordane will cause teratogenic effects in humans. Mutagenic effects Chlorinated hydrocarbon insecticides (such as chlordane) are generally not mutagenic (2). It was reported that 15 of 17 mutagenicity tests performed with chlordane showed no mutagenic effects (25). Thus, chlordane is weakly or nonmu- tagenic. Carcinogenic effects The EPA has classified chlordane as a probable human carcinogen. Chlordane has caused liver cancer in mice given doses of 30 to 64 mg/kg/day for 80 weeks (24). However, a study was done on workers at a manufacturing plant who had been exposed to chlorinated hydrocarbons for 34 years, including chlordane. No increase in any type of cancer was found (24,25). Organ toxicity In clinical studies of acute or chronic exposure to chlordane, the effects most frequently observed were central nervous system effects, liver effects, and blood disorders (25). Chronic exposure to chlordane may cause jaundice in humans. Chlor- dane may also cause blood diseases, including aplastic anemia and acute leukemia in rats (20). Fate in humans and animals Chlordane is absorbed into the body through the lungs, stomach, and skin. It is stored in fatty tissues as well as in the kidneys, muscles, liver, and brain (2,20). Chlordane has been found in human fat samples at concentrations of 0.03 to 0.4 mg/kg in U.S. residents (20). Chlorinated hydrocarbons stored in fatty tissues can be released into circulation if these fatty tissues are metabolized, as in starvation or intense activity (2). Chlordane that is not stored in the body is excreted through the urine and feces. Chlordane has been found in human breast milk (25). Rats that breathed chlordane vapor for 30 minutes retained 77% of the total amount inhaled. Rabbits that received four doses of chlordane stored it in fatty tissues, the brain, kidneys, liver, and muscles (2). Excretion of orally administered chlordane is slow and can take days to weeks. The biological half-life of chlordane in the blood serum of a 4-year-old child who © 2000 CRC Press LLC drank an emulsifiable concentrate of chlordane was 88 days. In another accidental poisoning of a 20-month-old child, the half-life was 21 days (20,25). Ecological effects Effects on birds Chlordane is moderately to slightly toxic to birds. The LD 50 in bobwhite quail is 83 mg/kg. The 8-day dietary LC 50 for chlordane is 858 ppm in mallard duck, 331 ppm in bobwhite quail, and 430 ppm in pheasant (9,26). Effects on aquatic organisms Chlordane is very highly toxic to freshwater invertebrates and fish. The LC 50 (96- hour) for chlordane in bluegill is 0.057 to 0.075 mg/L, and 0.042 to 0.090 mg/L in rainbow trout (9,17,26). Chlordane bioaccumulates in bacteria and in marine and freshwater fish species (17). Expected bioaccumulation factors for chlordane are in excess of 3000 times background water concentrations, indicating that bioconcentration is significant for this compound. Effects on other organisms (non-target species) Chlordane is highly toxic to bees and earthworms (26). Studies done in the late 1970s showed that the fatty tissues of land and water wildlife contained large amounts of cyclodiene insecticides, including chlordane (20). Environmental fate Breakdown in soil and groundwater Chlordane is highly persistent in soils, with a half-life of about 4 years. Several studies have found chlordane residues in excess of 10% of the initially applied amount 10 years or more after application (20). Sunlight may break down a small amount of the chlordane exposed to light (9). Evaporation is the major route of removal from soils (20). Chlordane does not chemically degrade and is not subject to biodegradation in soils. Despite its persistence, chlordane has a low potential for groundwater contamination because it is both insoluble in water and rapidly binds to soil particles, making it highly immobile within the soil (14). Chlordane molecules usually remain adsorbed to clay particles or to soil organic matter in the top soil layers and slowly volatilize into the atmosphere (14,20). However, very low levels of chlordane (0.01 to 0.001 µ g/L) have been detected in both ground and surface waters in areas where chlordane was heavily used (21,25). Sandy soils allow the passage of chlordane to groundwater. Breakdown in water Chlordane does not degrade rapidly in water. It can exit aquatic systems by adsorbing to sediments or by volatilization. The volatilization half-life for chlordane in lakes and ponds is estimated to be less than 10 days (20). Chlordane has been detected in surface water, groundwater, suspended solids, sediments, bottom detritus, drinking water, sewage sludge, and urban runoff, but © 2000 CRC Press LLC not in rain water. Concentrations detected in surface water have been very low, while those found in suspended solids and sediments are always higher (<0.03 to 580 µ g/L). The presence of chlordane in drinking water has almost always been associ- ated with an accident rather than with normal use (20). Breakdown in vegetation No data are currently available. Physical properties Technical chlordane is actually a mixture of at least 23 different components, including chlordane isomers, other chlorinated hydrocarbons, and by-products. It is a viscous, colorless or amber-colored liquid with a chlorine-like odor (9). Chemical name: 1,2,4,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-metha- noindene (9) CAS #: 57-74-9 Molecular weight: 409.83 (9) Water solubility: 0.1 mg/L @ 25 ° C (9) Solubility in other solvents: s. in most organic solvents, including petroleum oils (9) Melting point: 104–107 ° C (9) Vapor pressure: 1.3 mPa @ 25 ° C (9) Partition coefficient (octanol/water) (log): 2.78 (17) Adsorption coefficient: 20,000 (14) Exposure guidelines ADI: 0.0005 mg/kg/day (27) MCL: 0.002 mg/L (8) RfD: 0.00006 mg/kg/day (8) PEL: 0.5 mg/m 3 (8-hour) (8) Basic manufacturer Velsicol Chemical Corporation 10400 W. Higgins Rd. Rosemont, IL 60018–5119 Telephone:708-298-9000 6.2.2 Chlorobenzilate Figure 6.3 Chlorobenzilate. © 2000 CRC Press LLC Trade or other names Trade names for chlorobenzilate include Acaraben, Akar 338, Benzilan, Benz-o- chlor, ECB, Folbex, Geigy 338, and Kop-mite. Regulatory status The U.S. Environmental Protection Agency (EPA) has classified all formulations containing chlorobenzilate as Restricted Use Pesticides (RUPs). RUPs may be pur- chased and used only by certified applicators. It is classified as an RUP based on its ability to cause tumors in mice and its effects on the testes of rats. Aerial and ground foliar sprays are restricted to citrus use in the states of Arizona, California, Florida, and Texas for the control of mites. Considered toxicity class III — slightly toxic, products containing chlorobenzilate bear the Signal Word CAUTION. Introduction Chlorobenzilate is a chlorinated hydrocarbon compound. It is used for mite control on citrus crops and in beehives. It has narrow insecticidal action, killing only ticks and mites. Products are available as emulsifiable concentrate or wettable pow- der formulations. Toxicological effects Acute toxicity Chlorobenzilate is slightly toxic to humans. Symptoms of acute poisoning from ingestion of chlorobenzilate include incoordination, nausea, vomiting, fever, appre- hension, confusion, muscle weakness or pain, dizziness, wheezing, and coma. Symp- toms may occur within several hours after exposure. Death may result from discon- tinued breathing or irregular heartbeats (2,17). Chlorobenzilate is a severe eye irritant. It is mildly irritating to skin (2,17). The oral LD 50 is 2784 to 3880 mg/kg for chlorobenzilate in rats. The dermal LD 50 is greater than 10,000 mg/kg in rats and rabbits (2,9). Chronic toxicity Prolonged or repeated exposure to chlorobenzilate may cause the same effects as acute exposure (2,17). After continuous exposure to chlorobenzilate, 16 out of 73 workmen tested had abnormal electrical activity of the brain. The most severe brain activity changes were seen in those persons exposed to the herbicide for 1 to 2 years (2,17). Chronic skin exposure to chlorobenzilate may cause inflamed skin or rashes. Chronic eye exposure may cause conjunctivitis (2,17). Autopsies revealed intestinal irritation and bleeding in the lungs of rats poisoned by dietary doses of 25 mg/kg/day chlorobenzilate (2,17). Liver damage may be caused by repeated or prolonged contact (2,17). Reproductive effects A three-generation rat reproduction study resulted in reduced testicular weights, but did not affect reproduction. The results of another study indicate that chloroben- [...]... 6, 7,8,9,10,10-hexachloro-1,5,5a ,6, 9,9a-hexahydro -6 , 9-methano2,4,3-benzadioxathiepin 3-oxide (9) CAS #: 11 5-2 9-7 (alpha-isomer, 95 9-9 8-8 ; beta-isomer, 3321 3 -6 5-9 ) Molecular weight: 4 06. 96 (9) Solubility in water: 0.32 mg/L @ 22°C (9) Solubility in other solvents: s in toluene and hexane (9) Melting point: Technical material, 70–100°C (9) Vapor pressure: 1200 mPa @ 80°C (9) Partition coefficient (octanol/water ): Not available... coefficient (octanol/water ): 1411–2011 (9) Adsorption coefficient: 1000 (estimated) (14) Exposure guidelines ADI: Not available HA: Not available RfD: Not available TLV: Not available Basic manufacturer Sandoz Agro, Inc 1300 E Touhy Ave Des Plaines, IL 60 018 Telephone: 70 8 -6 9 9-1 61 6 Emergency: 70 8 -6 9 9-1 61 6 © 2000 CRC Press LLC 6. 2.7 Endosulfan Figure 6. 8 Endosulfan Trade or other names Trade or other names... camphor or cedar-like odor; the technical heptachlor is a soft wax (9) Chemical name: 1,4,5 ,6, 7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene (9) CAS #: 7 6- 4 4-8 Molecular weight: 373.34 (9) Water solubility: 0.0 56 mg/L (9) Solubility in other solvents: v.s in acetone, alcohol, benzene, carbon tetrachloride, cyclohexanone, kerosene, and xylene (9) Melting point: 95– 96 C (pure); 46 74°C (technical)... Not available Adsorption coefficient: 12,400 (14) Exposure guidelines ADI: 0.0 06 mg/kg/day (27) HA: Not available RfD: 0.00005 mg/kg/day (8) TLV: 0.1 mg/m3 (8-hour) ( 56) © 2000 CRC Press LLC Basic manufacturer FMC Corporation Agricultural Chemicals Group 1735 Market Street Philadelphia, PA 19103 Telephone: 21 5-2 9 9 -6 66 1 Emergency: 80 0-3 3 1-3 148 6. 2.8 Heptachlor Figure 6. 9 Heptachlor Trade or other names... guidelines ADI: 0.03 mg/kg/day (27) HA: 0.5 mg/L (longer-term) (35) RfD: 0.015 mg/kg/day (8) PEL: Not available Basic manufacturer Crystal Chemical Inter-America 10303 N.W Freeway, Suite 512 Houston, TX 77083 Telephone: 71 3-9 5 6- 6 1 96 6.2.4 Dalapon Figure 6. 5 Dalapon Trade or other names Trade names for dalapon include Alatex, Basinex P, Dalacide, Dalapon-Na (Dalapon-Sodium), Devipon, Ded-Weed, Dowpon,... (9) Chemical name: perchloro-1,1′-bicyclopenta-2,4-dienyl (9) CAS #: 222 7-1 7-0 Molecular weight: 474 .64 (9) Solubility in water: 25 mg/L @ 20–25°C (9) Solubility in other solvents: s.s in hot ethanol, acetone, and cyclohexanone; m.s in benzene, xylene, and other aromatic hydrocarbons (9) Melting point: 122–123°C (9) Vapor pressure: 1.3 mPa @ 25°C (9) Partition coefficient (octanol/water ): 1411–2011 (9)... years ( 46) Physical properties Pure dicofol is a white crystalline solid Technical dicofol is a red-brown or amber viscous liquid with an odor like fresh-cut hay (9,45) Chemical name: 2,2,2-trichloro-1,1-bis(y-chlorophenyl)ethanol (9) CAS #: 11 5-3 2-2 Molecular weight: 370.51 (9) Water solubility: 0.8 mg/L @ 25°C (9) Solubility in other solvents: s in most organic solvents (9) Melting point: 78.5–79.5°C... sodium and magnesium salts of dalapon (17) In its pure acid form, dalapon is a colorless liquid with an acrid odor As sodium-magnesium salts, it is a white to off-white powder (9,39) Chemical name: 2,2-dichloropropionic acid (9) CAS #: 12 7-2 0-8 (sodium salt); 7 5-9 9-0 (acid) Molecular weight: 164 .95 (sodium salt) (9) Water solubility: 900,000 mg/L @ 25°C (sodium salt) (9) Solubility in other solvents: alkali... Chemical name: tetrachloroisophthalonitrile (9) CAS #: 189 7-4 5 -6 Molecular weight: 265 .92 (9) Solubility in water: 0 .6 mg/L @ 25°C (9) Solubility in solvents: acetone s.s.; dimethyl sulfoxide s.s.; cyclohexanone s.s.; kerosene i.s.; xylene s.s (9) Melting point: 250–251°C (9) Vapor pressure: 1.3 Pa @ 40°C (9) Partition coefficient (octanol/water) (log) 437 (calc. ): 20.9 (17) Adsorption coefficient: 1380 (14)... pressure: Negligible at room temperature (9,45) Partition coefficent (octanol/water ): 19,000 (9,45) Adsorption coefficient: 5000 (estimated) (14) Exposure guidelines ADI: 0.002 mg/kg/day (27) MCL: Not available RfD: Not available PEL: Not available Basic manufacturer Rohm and Haas Co Agricultural Chemicals 100 Independence Mall West Philadelphia, PA 191 06 Telephone: 21 5-5 9 2-3 000 © 2000 CRC Press LLC 6. 2.6 . hydrocarbons, and by-products. It is a viscous, colorless or amber-colored liquid with a chlorine-like odor (9). Chemical name: 1,2,4,5 ,6, 7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-metha- noindene. odor. As sodium-magnesium salts, it is a white to off-white powder (9,39). Chemical name: 2,2-dichloropropionic acid (9) CAS #: 12 7-2 0-8 (sodium salt); 7 5-9 9-0 (acid) Molecular weight: 164 .95 (sodium. (27) HA: 0.5 mg/L (longer-term) (35) RfD: 0.015 mg/kg/day (8) PEL: Not available Basic manufacturer Crystal Chemical Inter-America 10303 N.W. Freeway, Suite 512 Houston, TX 77083 Telephone:71 3-9 5 6- 6 1 96 6.2.4