Mapping Three‐Dimensional Water‐Quality Data in the Chesapeake Bay Using Geostatistics1

Abstract:  Data interpretation and visualization software tools with geostatistical capabilities were adapted, customized, and tested to assist the Chesapeake Bay Program in improving its water‐quality modeling protocols. Tools were required to interpolate, map, and visualize three‐dimensional (3D) water‐quality data, with the capability to determine estimation errors. Components of the software, originally developed for ground‐water modeling, were customized for application in estuaries. Additional software components were developed for retrieval, and for pre‐ and post‐ processing of data. The Chesapeake Bay Program uses the 3D mapped data for input to the Bay water‐quality model that projects the future health of the Bay and its tidal tributary system. In determining water‐quality attainment criteria, 3D kriging estimation errors are needed as a statistical measure of uncertainty. Furthermore, given the high cost of installing and operating new monitoring stations, geostatistical techniques can assist the Chesapeake Bay Program in the identification of suitable data collection locations. Following the evaluation, selection, and development of the software components phase, 3D ordinary kriging techniques with directional semi‐variograms to account for anisotropy were successfully demonstrated for mapping 3D fixed station water‐quality data, such as dissolved oxygen and salinity. Additionally, an improved delineation tool was implemented to simulate the upper and lower pycnocline boundary surfaces allowing the segregation of the interpolated 3D data into three separate zones for a better characterization of the pycnocline layer.     

MATHEMATICAL ANALYSIS OF ARTIFICIAL RECHARGE FROM BASINS1

ABSTRACT: One of the most common methods of artificial recharge to the ground water is from basins. In this paper, seven analytical solutions that describe artificial recharge from basins are presented. Most of these solutions are derived by directly solving the general partial differential equation for ground water flow. The solutions differ in that they use different boundary conditions, basin shapes, and consider the nonlinearity of the artificial recharge problem differently. Use of each analytical solution is demonstrated in this paper by application to an example problem. A comparison of each analytical solution presented in this paper was made to give suggestions on their use, their ease of implementation, and their relative agreement. Although no attempt is made in the paper to conclude which analytical solution is best for all problems, some general conclusions can be stated on the applicability of the various analytical solutions. Of the analytical solutions presented in this paper, Glovers and Hantush's solutions for rectangular recharge basins are highly recommended. Baumanns solution for a circular basin also gave fairly reliable results and is very easy to evaluate numerically.     

Effect of restaurant types on compensation claims for work-related musculoskeletal disorders in France

Objectives. The economic burden of work-related musculoskeletal disorders (WMSDs) is industry specific. The objective was to analyse compensation claims for WMSDs among restaurant workers in France taking into account the type of restaurant. Methods. Data for 2014 were obtained from the French National Health Insurance Fund for Salaried Workers. A chi-square test was used to compare claims, incapacity and lost work day rates in different types of restaurant. Results. Prevalence for WMSDs differed significantly by the type of kitchen: collective restaurant (7.2/1000 workers), traditional restaurant (1.7/1000), and fast food restaurant (1.0/1000). There were more male claimants in traditional restaurant workers (51.0%) than in collective restaurant workers (40.1%) but more female claimants in collective restaurant workers (50.1%) than in traditional restaurant workers (39.4%). Permanent incapacity was significantly more prevalent in collective restaurant workers (49.6%), than in traditional (41.9%) and fast food (8.5%) restaurant workers. In collective restaurant workers, as a percentage, claims, permanent incapacity and lost work days increased with age range or work experience. Conclusions. Prevalence for WMSDs and therefore incapacity and lost work days are different according to the type of restaurant. Preventive strategies should take these differences into consideration.     

Innovative technologies to remove alkylphenols from wastewater: a review

Environmental Chemistry Letters - Alkylphenols and alkylphenol polyethoxylates are emerging hazardous contaminants due in particular to their endocrine-disrupting properties. These compounds...