HYDROGEOCHEMICAL RELATIONSHIPS USING PARTIAL CORRELATION COEFFICIENTS1

ABSTRACT: Sixty-nine groundwater samples were analyzed for six chemical parameters. Partial and simple correlation coefficients for these parameters indicate that partial coefficients are superior to simple coefficients in establishing geochemical relationships for the aqueous system evaluated. The improved reliability arises from the ability of partial correlation analysis to hold outside factors that may be affecting the two variables of interest, constant.     

NATIONAL WATER ASSESSMENT: NEEDED OR NOT?1

ABSTRACT A conceptual framework and the systematic collection of reliable information for application within the framework are the cornerstones of effective water planning. The ideal of strengthening these cornerstones was a driving force behind formation of the Water Resources Council and Council efforts, during its life, to develop the Principles and Standards and to complete two National Water Assessments. The Assessments contained voluminous data but never really became an integral component of the national water planning process. Before being disbanded in 1982, the Council solicited several appraisals of its assessment process. This paper reports one made by the university community in which experiences and opinions were obtained from 108 water research administrators and water policy experts.     

THE EFFECTS OF DEICING SALTS ON WATER CHEMISTRY IN PINHOOK BOG,INDIANA1

ABSTRACT: A five-year study was conducted to identify the effects of road salt intrusion on the water chemistry of Pinhook Bog following operation of an uncovered salt storage pile adjacent to the bog for ten years. A distinct pattern of elevated salt concentrations was observed in the interstitial waters of the surface peat that corresponded to observed alterations in the bog vegetation. Yearly mean salt concentrations as high as 468 mg/l sodium and 1215 mg/l chloride were recorded in the plant root zone of the peat mat. The salt concentrations decreased significantly each year from 1979 to 1981 throughout the impacted area. Some increases of a lesser magnitude occurred in 1982 and 1983. Analysis of salt movements suggested that vertical transport by water movement was responsible for concentration changes. The major declines in salt levels occurred in the spring following snowmelt and heavy precipitation events. Evapotranspiration during periods of drought resulted in the gradual increases in surface peat salt concentrations. Diverted highway runoff was shown to be the major continuing source of sodium chloride contamination and was the likely source of the elevated calcium, magnesium, potassium, bicarbonate, and pH levels also observed in the impacted area.     

INTERVENTION ANALYSIS OF WATER USE RESTRICTIONS,AUSTIN, TEXAS1

ABSTRACT: Mandatory water conservation in the form of restrictions on outdoor watering, car washing, and recreation was implemented in the City of Austin, Texas, during the summers of 1984 and 1985. Three different stages of restrictions were implemented limiting the number of watering hours per day, as well as a restriction that allowed lawn watering once every five days according to the last digit of the street address, Intervention analysis using a transfer function-noise model of daily water use is applied to assess the impact of the restrictions. Compared to a peak water use rate of about 170 MGD, it is shown that mandatory restrictions in 1984 reduced water use by an average of 13.5 MGD, while similar restrictions during the summer of 1985 reduced usage by an average of 5.5 MGD. Lawn watering restrictions on a five-day cycle produced a corresponding five-day cycle in water use of more than 10 MGD in amplitude in 1985. An alternative lawn watering scheme that eliminates this cycle is prescribed.     

Differences in the importance of work outcomes between full-time and part-time hospital employees

This study examined differences in the importance of work outcomes between full-time and part-time hospital employees in a sample drawn from five western hospitals (N = 1,876). Work status was operationalized by classifying respondents into four categories based on hours worked per week. Exploratory factor analysis showed that work outcomes may be classified as extrinsic (pay and fringe benefits) and instrinsic (being informed about the job, participating in decision-making, and doing the job well). Confirmatory factor analyses demonstrated that this two-factor structure fits the data well for all four work status categories although the factor loadings differed across categories. Multivariate analyses of variance and covariance indicated that statistically significant differences in the importance of extrinsic and intrinsic outcomes exist for full-time and part-time employees and that these differences persist when various social and demographic variables are held constant. Employees who work fewer hours per week tend to assign less importance to the work outcomes measured in this study. The results suggest that theoretical models of variables such as job satisfaction should take into account work status differences in the importance of work-related outcomes. In addition, managers may find that workers respond to different reward structures depending on the degree of their involvement in the organization.     

PERSISTING SEDIMENT YIELDS AND SEDIMENT DELWERY CHANGES1

ABSTRACT: The Buffalo River is a tributary to the Mississippi River in west-central Wisconsin that drains a watershed dominated by agricultural land uses. Since 1935, backwater from Lock and Dam 4 on the Mississippi River has inundated the mouth of the Buffalo's valley. Resurveys of a transect first surveyed across the lake in 1935 and cesium-137 dating of backwater sediments reveal that sedimentation rates at the Buffalo's mouth have remained unchanged since the mid-1940s. Study results indicate that sediment yields from the watershed have persisted at relatively high levels over a period of several decades despite pronounced trends toward less cultivated land and major efforts to control soil erosion from agricultural land. The maintenance of sediment yields is probably due to increased channel conveyance capacities resulting from incision along some tributary streams since the early 1950s. Post-1950 incision extended the network of historical incised tributary channels, enhancing the efficient delivery of sediment from upland sources to downstream sites.     

Can progress in reducing alcohol-impaired driving fatalities be resumed? Results of a workshop sponsored by the Transportation Research Board,Alcohol, Other Drugs,and Transportation Committee (ANB50)

Objective: Despite successes in the 1980s and early 1990s, progress in reducing impaired driving fatalities in the United States has stagnated in recent years. Since 1997, the percentage of drivers involved in fatal crashes with illegal blood alcohol concentration (BAC) levels has remained at approximately 20 to 22%. Many experts believe that public complacency, competing social and public health issues, and the lack of political fortitude have all contributed to this stagnation. The number of alcohol-related crashes, injuries, and fatalities is still unacceptable, and most are preventable. The public needs to be aware that the problem presented by drinking drivers has not been solved. Political leaders need guidance on which measures will affect the problem, and stakeholders need to be motivated once again to implement effective strategies.

Methods: The National Academy of Sciences (NAS) Transportation Research Board (TRB), Alcohol, Other Drugs, and Transportation Committee (ANB50) sponsored a workshop held at the NAS facility in Woods Hole, Massachusetts, on August 24–25, 2015, to discuss the lack of progress in reducing impaired driving and to make recommendations for future progress. A total of 26 experts in research and policy related to alcohol-impaired driving participated in the workshop. The workshop began by examining the static situation in the rate of alcohol-impaired driving fatal crashes to determine what factors may be inhibiting further progress. The workshop then discussed 8 effective strategies that have not been fully implemented in the United States. Workshop participants (16 of the 26) rated their top 3 strategies.

Results: 3 strategies received the most support: 1. Impose administrative sanctions for drivers with BACs = 0.05 to 0.08 g/dL.

2. Require alcohol ignition interlocks for all alcohol-impaired driving offenders.

3. Increase the frequency of sobriety checkpoints, including enacting legislation to allow them in the 11 states that currently prohibit them.

5 other important strategies included the following: (1) increase alcohol taxes to raise the price and reduce alcohol consumption; (2) reengage the public and raise the priority of impaired driving; (3) lower the illegal per se BAC limit to 0.05 for a criminal offense; (4) develop and implement in-vehicle alcohol detection systems; and (5) expand the use of screening and brief interventions in medical facilities.

Conclusions: Each of these strategies is proven to be effective, yet all are substantially underutilized. Each is used in some jurisdictions in the United States or Canada, but none is used extensively. Any one of the 3 strategies implemented on a widespread basis would decrease impaired driving crashes, injuries, and fatalities. Based on the research, all 3 together would have a substantial impact on the problem.     

Assessing the effects of surface-bound humic acid on the phototoxicity of anatase and rutile TiO2 nanoparticles in vitro

In this study,the cytotoxicity of two different crystal phases of TiO₂ nanoparticles,with surface modification by humic acid（HA）,to Escherichia coli,was assessed.The physicochemical properties of TiO₂ nanoparticles were thoroughly characterized.Three different initial concentrations,namely 50,100,and 200 ppm,of HA were used for synthesis of HA coated TiO₂ nanoparticles（denoted as A/RHA50,A/RHA100,and A/RHA200,respectively）.Results indicate that rutile（LC50（concentration that causes 50%mortality compared the control group）=6.5）was more toxic than anatase（LC₅0=278.8）under simulated sunlight（SSL）irradiation,possibly due to an extremely narrow band gap.It is noted that HA coating increased the toxicity of anatase,but decreased that of rutile.Additionally,AHA50 and RHA50had the biggest differences compared to uncoated anatase and rutile with LC₅0of 201.9 and21.6,respectively.We then investigated the formation of reactive oxygen species（ROS）by TiO₂ nanoparticles in terms of hydroxyl radicals（OH）and superoxide anions（O₂^-）.Data suggested that O₂^- was the main ROS that accounted for the higher toxicity of rutile upon SSL irradiation.We also observed that HA coating decreased the generation of OH and O₂^- on rutile,but increased O₂^- formation on anatase.Results from TEM analysis also indicated that HA coated rutile tended to be attached to the surface of E.coli more than anatase.