Development and Evaluation of the Diffusive Gradients in Thin Films (DGT) Techniques for the Measurement of Nutrient Concentrations in Natural Waters

Abstract

Due to rapid industrialisation, the growing global population, and the impacts of climate change, the availability and quality of water resources around the world has become degraded. Some regions are suffering water shortages despite sufficient water reserves, because surface and ground waters are contaminated to such a degree that they have become inadequate for potable use. Agricultural practices, industrial discharges and human wastewater are responsible for most contamination of water. Nitrogen (ammonium, nitrate and nitrite) and phosphorus (phosphate) are the most common nutrients in freshwaters and estuaries that impact water quality. Excess nutrient loadings to water bodies can affect many aquatic organisms and, ultimately, contribute to the degradation of freshwater, estuarine and coastal marine ecosystems. Furthermore, high concentrations of nutrients in drinking water sources can cause health impacts to human beings. Due to the potential sporadic nature of the contamination sources, grab sampling may fail to identify contamination events. Nutrient loadings to waterways from point and non-point sources are of major ecological concern and represent one of the most significant water quality issues in surface water bodies, and hence require use of accurate and representative approaches to monitor nutrient concentrations. DGT as diffusive gradients in thin films, a well-established passive sampling technique, allows determination of time-weighted average measurements over environmentally relevant time-scales.