Guidelines for Canadian drinking water quality boron: Exposure considerations

The average total daily boron intake from environmental media, food and drinking water for the general Canadian population ranges from 3 to 92 μg/kg body weight (bw) per day, depending on the age group, with an estimated 3% to 16% of total dietary intake attributable to drinking water (ECCC and Health Canada, 2016). Food is the main source of boron exposure, with fruits and vegetables contributing 40% to 60% of dietary intake (ECCC and Health Canada, 2016). Consumer products can also contribute significantly to total daily intake, with an upper bound exposure estimate of 2819 μg/kg bw per event for direct ingestion of modelling clay by children (ECCC and Health Canada, 2016). Soil, air and dust are likely negligible sources of boron exposure (WHO, 2009; ECCC and Health Canada, 2016). The large range in total daily intake results from the variability of boron in foods, drinking water, and consumer products and their use patterns, and from emissions into the environment from natural weathering and human activities (Becking and Chen, 1998; ECCC and Health Canada, 2016).