Boron exposure assessment using drinking water and urine in the North of Chile

Boron is an essential trace element for plants and humans however it is still an open question what levels of boron are actually safe for humans. This study, conducted between 2006 and 2010, measured exposure levels of boron in drinking water and urine of volunteers in Arica, an area in the North of Chile with high levels of naturally occurring boron. Samples were taken of tap and bottled water (173 and 22, respectively), as well as urine from 22 volunteers, and subsequently analyzed by inductively coupled plasma spectroscopy (ICP-OES). Boron varied in public tap water from 0.22 to 11.3 mg L− 1, with a median value of 2.9 mg L− 1, while concentrations of boron in bottled water varied from 0.01 to 12.2 mg L− 1. Neither tap nor bottled water samples had concentrations of boron within WHO recommended limits. The concentration of boron in urine varied between 0.45 and 17.4 mg L− 1, with a median of 4.28 mg L− 1 and was found to be correlated with tap water sampled from the homes of the volunteers (r = 0.64). Authors highly recommend that in northern Chile – where levels of boron are naturally high – that the tap and bottled water supplies be monitored in order to protect public health and that regulatory standards also be established for boron in drinking water in order to limit exposure.

► Boron exposure gives the baseline to establish a safe range for Boron in human populations. ► This study represents the first detailed assessment of boron exposure in Chile. ► Environmental monitoring of the public supply system showed ranges from 0.22 to 11.30 mg L− 1 of B. ► Urinary levels of boron was greater than boron in water and others non-exposed populations. ► Detailed regulatory standards for boron in drinking water should be given legislative priority.