1,4-dichlorobenzene environmental data

Although there is no reason to suspect that the pharmacokinetics of 1,4-dichlorobenzene differs in children and adults, scant data are available to support or disprove this statement. Studies of absorption, distribution, metabolism, and excretion in children would aid in determining if children are at an increased risk, particularly if conducted in an area where a high-dose acute or low-dose chronic exposure to an environmental source were to occur. With regard to exposure during development, additional research on maternal and fetal/neonatal toxicokinetics, placental biotransformation, the mechanism of... 

According to the Toxics Release Inventory, in 1996 estimated releases of 1,4-dichlorobenzene of 236,502 pounds (118 tons) to the air from 20 large processing facilities accounted for about 31% of the total environmental releases (TRI96 1998). Table 5-1 lists amounts released from these facilities. The TRI data should be used with caution because only certain t5 es of facilities are required to report (EPA 1997b). Therefore, this is not an exhaustive list. 

Reliable evaluation of the potential for human exposure to 1,4-dichlorobenzene depends in part on the reliability of supporting analytical data from environmental samples and biological specimens. In reviewing data on 1,4-dichlorobenzene levels monitored or estimated in the enviromnent, it should also be noted that the amount of chemical identified analytically is not necessarily equivalent to the amount that is bioavailable. The analytical methods available for monitoring 1,4-dichlorobenzene in various environmental media are detailed in Chapter 6. 

As part of the Third National Health and Nutrition Evaluation Survey (NHANES III), the Environmental Health Laboratory Sciences Division of the National Center for Environmental Health, Centers for Disease Control and Prevention, will be analyzing human blood samples for 1,4-dichlorobenzene and other volatile organic compounds. These data will give an indication of the frequency of occurrence and background levels of these compounds in the general population. 

Howard PH. 1989. 1,4-dichlorobenzene. Handbook of environmental fate and exposure data for organic chemicals. 1 250-262. 

PROBABLE FATE photolysis, expected to oecur slowly oxidation no data available on aqueous oxidation, oxidized by hydroxyl radicals in atmosphere hydrolysis not important process first-order hydrolytic half-life >879 yrs volatilization volatilizes at a relatively rapid rate, half-life is about 10 hr volatilization from soil surfaces is expected to be a signifieant transport mechanism sorption sorbed by organic materials adsorption to sediment expected to be a major environmental fate process based on research in the Great Lakes area biological processes bioaccumulates more than chlorobenzene, biodegradation is not as significant as volatilization slightly persistent in water, half-life 2-20 days approximately 98.5% of 1,3-dichlorobenzene ends up in air 1% ends up in water the rest is divided equally between terrestrial soils and aquatic sediments. 

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