Multivariate analyses for monitoring EDCs and PPCPs in a lake water.

The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCP), present at trace level in surface waters, is often expensive, time-consuming, and complex. Implementing effective monitoring strategies for these compounds is essential to determine the types of analytes, sampling locations, and sampling frequencies. Multivariate analyses were used to investigate the patterns of EDCs and PPCPs in Lake Mead, Nevada, for these purposes. The results of cluster analysis and principal component analysis to identify the patterns among compounds demonstrated that selected pharmaceuticals tended to be present together with each other, whereas hormones did not show patterns with other compounds. The results of cluster analysis and discriminant analysis to investigate the spatial variation of EDCs and PPCPs eliminated redundant sampling locations, verifying the current selection of sampling locations in Lake Mead. The results of autocorrelation provided optimal sampling frequencies for EDCs and PPCPs, suggesting either monthly or quarterly monitoring of these compounds in Lake Mead. The patterns of the compounds could be site specific; depending on weather and hydrological conditions of the water systems, but this study's approaches will facilitate effective assessment and monitoring of EDCs and PPCPs in surface water.

The ROH,UV concept to characterize and the model uv/H202 process in natural waters.

A new concept is introduced to characterize and model the UV/H2O2 advanced oxidation process (AOP) in water. Similarto the Rct concept used to describe OH radical exposure per ozone dose, the ROH,UV concept is defined as the experimentally determined *OH radical exposure per UV fluence. ROH,UV was determined by examining the destruction of a probe compound, para-chlorobenzoic acid in four different waters: DI water and three natural waters. ROH,UV was found to be affected greatly by water quality, specifically background *OH radical scavenging, which competed forthe formed *OH radical with the probe compound, and background UV absorbance, which screened UV irradiation from the hydrogen peroxide. The ROH,UV values determined in the experiments using low-pressure Hg lamp were greater than those for the medium-pressure Hg lamp . Finally, the ROH,UV concept was utilized to calculate an overall scavenging factor for each water matrix, and this was successfully utilized in conjunction with the steady-state *OH radical model to improve the prediction of the oxidation of endocrine-disrupting compounds 17-alpha-ethinyl estradiol and 17-beta-estradiol in the natural waters.