ABSTRACT
River floodplains sustain irrigated agriculture worldwide. Despite generalised groundwater level falls, limited hard data are available to apportion groundwater sources in many irrigated regions. In this paper, we propose a workflow based on: hydrochemical analysis, water stable isotopes, radiocarbon contents and multivariate statistical analysis to facilitate the quantification of groundwater source attribution at regional scales. Irrigation water supply wells and groundwater monitoring wells sampled in the alluvial aquifer of the Condamine River (Queensland, Australia) are used to test this approach that can easily be implemented in catchments worldwide. The methodology identified four groundwater sources: 1) river/flood water; 2) modified river/flood water; 3) groundwater recharged through regional volcanic materials and 4) groundwater recharged predominantly through sands and/or sandstone materials. The first two sources are characterised by fresh water, dominant sodium bicarbonate chemistry, short residence time and depleted water stable isotope signatures. Groundwater sources 3 and 4 are characterised by saline groundwater, sodium chloride chemistries, enriched water stable isotopes and very low radiocarbon contents, inferred to correspond to long residence times. The majority of wells assessed are dominated by flood water recharge, linked to decadal >300 mm rainfall events and associated flooding in the region. The approach presented here provides a groundwater source fingerprint, reinforcing the importance of floodwater recharge in the regional water budgets. This apportioning of groundwater sources will allow irrigators, modelers and managers to assess the long-term sustainability of groundwater use in alluvial catchments.
ABSTRACT
OBJECTIVES: To review the recent literature and develop a logical strategy with which to approach the diagnosis and treatment of osteoporosis, based on clinical evidence and accepted practices. METHODS: Published reports from 1983 through 1997 obtained by MEDLINE search were reviewed and analyzed by both authors. RESULTS: Osteoporosis is a widespread medical condition readily identifiable by current diagnostic modalities, including quantitative computed tomography, single and dual x-ray absorbtiometry, radio-absorbtiometry, and ultrasound. Properly implemented prevention and treatment strategies, such as calcium and vitamin D supplementation, exercises, hormone replacement therapy, alendronate, and calcitonin, may reduce the future fracture risk in many individuals. An algorithm is provided based on currently available clinical evidence for the evaluation and treatment of osteoporosis. CONCLUSIONS: Expanded use of currently available and emerging diagnostic and therapeutic modalities should lead to decreased fracture rates and a resultant increase in quality of life for patients with osteoporosis.
