Abstract
Boron is a ubiquitous element in the environment and is required for normal plant development. It is not classed as essential for animals or humans but is known to influence many processes within the body such as macromineral metabolism, bone development, immune function, inflammatory disease and the functions of several enzymes. The problem of boron toxicity in the environment is a relatively rare situation when compared to deficiency status. The region of San Jose de Jachal, San Juan (SJ), Argentina, provided a unique area of investigation as it suffers from enhanced levels of boron in waters, soils, sediments and plants. This work has investigated the impact of boron and other key elements (namely As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, K, Se, Na and Zn) in this region with respect to the environmental levels and the effect on the human population, through scalp hair analysis. This was compared to a second 'control' area of Argentina, namely General Roca, Rio Negro (RN). In order to achieve this, validated sample preparation methods were developed and optimised analytical conditions were used for measurement by a variety of techniques, namely flame atomic absorption spectrometry, atomic emission spectrometry, inductively coupled plasma mass spectrometry and molecular spectroscopy. This work showed that boron in the main river system in SJ ranged from 2.2 to 7.1 mg/l whereas RN waters were found to contain 0.03-2.3 mg/l. The sediments showed a similar trend, with levels ranging from 25-147 mg/kg for SJ and 34-93 mg/l for RN. Significant correlations (P<0.05) were found between water and sediment levels, and statistical differences were observed between the two populations for boron in waters and sediment (P<0.05). Additionally, the mobility of boron in grapevines and wine was examined. Whilst it was not possible to determine the mechanism of transport through the plant, boron is a labile element and was found in appreciable quantities in the resultant grape juice and wine. A database of elemental levels in wine (B, Ba, Ca, Cu, Pb, Li, Mg, Mn, Rb, Sr and Zn) was produced in order to compare wines from SJ to other countries. In general, no major differences were observed which could have substantial impact on the local economy if wine were to be produced in this region. The application of chemometrics was also explored using the wine data. The use of scalp hair as a biomonitor for boron (and other key elements) in relation to the health status of the two populations was uniquely described. Highly significant differences (P<0.001) were found between the two groups in terms of their elemental content for boron as well as Cd, Ca, Cu, Fe, Pb, Mg, Mn and Na. The effects of gender, age and health status were also investigated. Of greatest relevance, was the relationship between boron and calcium with reported bone conditions/arthritis (P<0.05), which was in agreement with previous studies monitoring other tissues.