Evaluation of Sampling Strategies on Load Estimation For Illinois River at Highway 59

This study investigated the precision and accuracy of the two load calculation techniques. The study compared total phosphorus loads calculated by integration of Arkansas Water Resources Center (AWRC) intensive sampling data to loads calculated by a regression technique (rating curve) using fewer data. The 1998 AWRC dataset from the Illinois River at Arkansas Highway 59 was sub-sampled in a manner to simulate fixed period monitoring schemes supplemented with storm sampling. The ESTIMATOR software program was used to calculate loads. These loads were compared to the integrated load. The error of the integrated load when the variation in concentration between samples is not linear and the sensitivity of the integrated load to sampling interval were also investigated. The results show that the central tendency of the ESTIMATOR loads is accurate when storm data are included, but that the 95% confidence interval represents up to +/- 30-40% difference from the integrated load for individual estimates. More frequent sampling and more samples lead to more accurate loads. The results indicate that the central tendency of load estimates would be accurate for a method that uses a regression model with 32 or more samples including storm samples

Investigation of Optimum Sample Number and Timing for Determining Pollution Loads

In order to determine the impacts of non point source (NPS) pollution and to develop Total Maximum Daily Loads (Tr\tfDLs), accurate measurements of pollution loads in streams are critical. The objectives of this study were to accurately detemline pollutant loads at two sites by intensive storm sampling, to develop sub-sampling and other data analysis techniques, to detemline the effect of sample interval on load calculation accuracy, and to find the minimum sample interval required to determine storm loads at a required accuracy. The two stream sites used were a 1st order and a 3rd order stream in the Illinois River basin in Arkansas. The samples were analyzed for NO3-N, ~-N, TKN, Ortho-P, Total-P, and TSS. Storm loads were calculated by multiplying discharged volume by concentration for each sampling interval and summing over the storm. The loads calculated using the 30 minute interval data were termed the best estimate load. Loads were also calculated for 60, 120, and 240 minute sampling intervals using subsets of the data. The load estimates for the longer sampling intervals were expressed as a percentage of the best estimate load. The results showed that as sampling interval increased the error of the load estimate increased. For example, the Moores Creek data indicated that if we desire that the calculated TSS load is within 5% of the best estimate load with a 95% confidence level, we need to sample approximately every 50 minutes during a storm. This optimum sampling interval varies with the parameter measured and with the stream order. The information gained from this study should help water quality investigators develop sampling schemes to meet their goals of accuracy, precision, efficiency, and cost

Locating NAPLs in Ground Water Using Partitioning Fluorescent Dyes

A major challenge in ground water remediation is locating nonaqueous phase liquids (NAPLs). Partitioning tracers can be used to identify NAPL sources between injection and extraction wells. NAPLs are only slightly soluble in water, pose a long-term source of groundwater contamination, and can be difficult to remove. The complexity of recovery processes requires the development of new technologies that guarantee cost effective methods for locating and quantifying NAPLs. Traditional methods like soil coring have been inefficient since they underestimate the quantity of NAPLs and are expensive. Partitioning tracer tests are some of the most recent methods developed for locating these contaminants and determining the volume of the NAPL present in the inter-well zone. The results of the tests can be used to develop remediation techniques to recover NAPLs entrapped in the contaminated zone. Fluorescent dyes may be useful as partitioning tracers. They can be analyzed quickly at the field site, resulting in a shorter analysis time and lower costs than other partitioning tracers. This project pursued the selection of suitable tracers and the development of partitioning tracer techniques to locate and quantify NAPLs in the subsurface

Enantioselective BINOL-phosphoric acid catalyzed Pictet-Spengler reactions of N-benzyltryptamine

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Synthesis and evaluation of tryprostatin B and demethoxyfumitremorgin C analogues

Tryprostatin B and demethoxyfumitremorgin C are fungal inhibitors of mammalian cell cycle progression at the G(2)/M transition. N-Alkyl derivatives of the L-TrP-L-Pro diketopiperazine were prepared as analogues of tryprostatin B, and two of these were more active than the natural product. A second series of cis- and trans-tetrahydro-beta-carbolines annulated to a diketopiperazine were prepared as analogues of demethoxyfumitremorgin C. The nature of the alkyl substituent, as well as its cis or trans relationship in the tetrahydro-beta-carboline ring, was found to have a significant effect on cytotoxic activity. Small cis-alkyl substituents fall into the demethoxyfumitremorgin C family, whereas bulky benzyl trans compounds appear to act via a different mechanism of action