| Synopsis: |
This text evaluates the risks to human health and the environment posed by boron, a naturally occurring element widely distributed, in the form of various inorganic borates, in the oceans, sedimentary rocks, coal, shale, and some soils. Boron is also used in laundry bleach and in the manufacture of glass, glass products, fertilizers and herbicides, antiseptics, and pharmaceuticals. A section on sources of human and environmental exposure cites evidence that boron enters the environment mainly through volatization from seawater, volcanoes, geothermal steam, and natural weathering of clay-rich sedimentary rock. The environmental behaviour of boron is also covered, concluding that boron does not persist in the atmosphere to a significant degree, absorbs onto soil particles, accumulates in acquatic and terrestrial plants, but does not magnify through the food chain. A section on environmental levels and human exposure cites diet and drinking-water as the principal sources of exposure for the general population. The most extensive section in the book reviews findings from toxicity studies in laboratory mammals and test systems.General clinical signs of exposure are described as depression, ataxia, occasional convulsions, decreased body temperature, and violet-red colour of skin and mucous membrances. |