Data Needs

Physical and Chemical Properties. The solubilities of many boron minerals are not known precisely, but this lack of detailed information may not be a major limitation, since it appears unlikely that mineral equilibria significantly influence the fate of boron in the environment.

Production, Import/Export, Use, and Disposal. The production volume and uses of boron and boron compounds are well documented (Ferguson et al. 1982; HSDB 1989; U.S. Bureau of Mines 1989). However, data on disposal methods and volume would allow better estimation of human exposure to boron from this source.

According to the Emergency Planning and Community Right-to-Know Act of 1986, 42 U.S.C. Section 11023, industries are required to submit chemical release and off-site transfer information to the EPA. The Toxics Release Inventory (TRI), which contains this information for 1987, became available in May of 1989. However, neither boron nor boron-related compounds are currently listed in the database. This database will be updated yearly and should provide a list of industrial production facilities and emissions.

Environmental Fate. The only quantifiable mechanism that influences the fate of boron is soil adsorption (Rai et al. 1986). Additional research with soils that do not have significant quantities of aluminum and iron oxide may provide a more comprehensive view of the mobility of boron in the environment.

Bioavailability from Environmental Media. Boron compounds can be absorbed following inhalation of contaminated workplace air, ingestion of contaminated food, or through damaged skin (Draize and Kelley 1959; Wong et al. 1964). The most significant routes of exposure near hazardous waste sites are likely to be through drinking boron-contaminated water and ingestion of locally grown food (Beyer et al. 1983; CLPSD 1989). While exposure can occur by these routes, quantitative data on amounts absorbed or are bioavailable would be useful in clarifying the toxic potential of boron in humans.

Food Chain Bioaccumulation. Only one study was located where boron bioconcentration was actually measured (Tsui and McCart 1981). Future research may be helpful, but it appears that boron is not significantly bioconcentrated. There are no data on the biomagnification of boron in the food chain, but it is not likely that bioaccumulation is a major environmental concern.

Exposure Levels in Environmental Media. Data on boron levels in surface water and soil are extensive (Butterwick et al. 1989; Eckel and Langley 1988; EPA 1986b), but additional data on air, food, and drinking water concentrations of boron would be useful in increasing the accuracy of human exposure estimates.

Exposure Levels in Humans. Normal levels of boron in human blood and urine have been reported (Stokinger 1981). Additional data on blood and/or urine concentrations in individuals with potentially high exposure to boron would be useful in assessing the magnitude of human exposure.

Exposure Registries. No exposure registries for boron were located. This compound is not currently one of the compounds for which a subregistry has been established in the National Exposure Registry. The compound will be considered in the future when chemical selection is made for subregistries to be established. The information that is amassed in the National Exposure Registry facilitates the epidemiological research needed to assess adverse health outcomes that may be related to the exposure to this compound.

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