Distribution of boron in the environment

Abstract

The findings of a study to identify and quantify the orders of magnitude for major reservoirs and flows of boron (B) in the environment are outlined. The orders of magnitude for B reservoirs and flows arising through natural processes, such as the hydrological cycle and volcanism, are compared with those arising from anthropogenic activities, such as coal combustion and the extraction and use of borates for commercial purposes. The major stores and reservoirs for B have been identified, in order of magnitude, as the continental and oceanic crusts (10(18) kg B), the oceans (10(15) kg B), groundwater (10(11) kg B), ice (10(11) kg B), coal deposits (10(10) kg B), commercial borate deposits (10(10) kg B), biomass (10(10) kg B), and surface waters (10(8) kg B). The largest flows of B in the environment arise from the movement of B into the atmosphere from oceans, at between 1.3 x 10(9) kg and 4.5 x 10(9) kg B per annum. Other hydrological flows are also important. Drainage from soil systems into groundwaters and surface waters accounts for between 4.3 x 10(8) kg and 1.3 x 10(9) kg B per annum. B mining and volcanic eruptions represent the next most significant B flows, accounting for approx 4.0 x 10(8) kg and 3.0 x 10(8) kg B, respectively.

Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

“…10 9%)). 13,62 The coating on Al substrate contains boron and carbon in a ratio of B/C ¼ 3.6. The same levels of O and N content as in the coating on Si (Fig.…”

Enhanced boron rejection by NF/RO membranes by complexation with polyols: Measurement and mechanisms

“…All other chemicals used were purchased from Sigma-Aldrich (Castle Hill, Australia) at reagent grade. NaCl, CaCl 2 , NaHCO 3 , and B(OH) 3 were used to prepare feed solution. NaOH and HCl were used for pH adjustment.…”

“…Membrane compaction was conducted for at least 1 h until a stable baseline flux was obtained. The electrolyte solution, which contains 10 mM NaCl, 1 mM CaCl 2 , 1 mM NaHCO 3 , predetermined concentration of B(OH) 3 and one of the polyols, was then added to the feed reservoir making up to the total feed volume of 10 L. For all experiments, the cross-flow velocity and permeate flux were adjusted to be 42 cms -1 and 42 Lm -2 h -1 , respectively. The temperature of the feed solution was kept constant at 20 ± 0.1 o Experiments were conducted at two different boron concentrations: 0.43 mM (4.6 mgL C during the experiment.…”

“…The boron abundance in surface water is generally less than 0.5 mgL -1 , but the level in seawater is significantly higher with an average concentration of approximately 4.6 mgL -1 . Concentrations of up to 6.5 mgL -1 have been reported in groundwater supplies, but these high concentrations are usually associated with seawater intrusion [1][2][3]. Although boron is an important nutrient for plants and animals, the range between deficient and toxic levels is very narrow.…”

Cytogenetic and oxidative alterations after exposure of cultured human whole blood cells to lithium metaborate dehydrate

“…It is found in the environment primarily combined with oxygen to form compounds called borates. They are commonly found in nature, and are present in oceans, sedimentary rocks, coal, shale, and some soils (Argust 1998;Turkez et al 2012a). Boron compounds are used in borosilicate glass products, but are also used in agriculture, in fire retardants, and in soaps and detergents (Richold 1998).…”