In both surface and ground waters, levels of phosphate are generally low, but where levels rise because of environmental contamination, growth of algae can occur (a process termed 'eutrophication'). This subsequently depletes oxygen from the water and can result in the death of aquatic life. Ultimately, because these surface and ground waters are used as drinking water, build up of toxic algal blooms represents a major human health concern.
Robust methods for measuring these phosphates in surface and ground waters are therefore necessary. UV-vis spectrophotometry is a mature and reliable technique that offers a solution to accurate measuement of phosphates in surface and ground waters.
Across environmental agency, government, water supply company and university laboratories, a number of methods are currently used to address this challenge:
- inductively coupled plasma (ICP)
- ion chromatography
- photometric determination
- flow analysis
A recent study examined the used of photometric detection for the analysis of ortho-phosphates in five different Bavarian lakes in Germany. The study compared a test kit photometric method using ammonium molybdate with a standard DIN EN ISO 6878 method.
Photometry is a reliable and sensitive method for the analysis of ortho-phosphate in ground and surface water, compared to the traditional ion chromatography method. Easy handling and cost benefits mean that the test kits are an alternative to the DIN EN ISO 6878 method.
A full description of the methodology, and details of the instrumentation used, can be viewed on-demand.