EFFECTS OF DIVERSIONS ON THE NORTH AMERICAN GREAT LAKES1

ABSTRACT: Water level fluctuations of the Great Lakes often have created regional controversies among the states and Canadian provinces that share this vast resource. Even though the 100-year range of their water levels is only four to five feet, episodes of high and low Great Lakes water levels have been a recurring problem throughout the twentieth century. The possibility of increased diversion and consumptive use has exacerbated the existing conflicts over how to manage this water resource. A research project evaluated the effects of interbasin diversion on the Great Lakes system and on the industries that depend on the maintenance of historical water levels, namely hydropower and commercial navigation. The simulation approach employed in this research and some of the important findings are presented. The approach is similar to that used in recent government studies of Great Lakes water level regulation. Several significant modifications were made specifically addressing the diversion issue. Aggregate annual impacts to hydropower and shipping resulting from a diversion of 10,000 cubic feet per second were found to vary from 60 to 100 million dollars. Increases in impacts as a function of diversion rate are nonlinear for the navigation industry.     

Safety climate

Safety climate, the objective measurement of attitudes and perceptions toward Occupational Health & Safety (OH&S) issues, has been largely ignored and measures such as lost time and frequency rate have been used to determine the efficacy of OH&S programs. Yet, it is clear that measuring the precursors of accidents identified in a safety climate analysis provides a powerful proactive management tool. This paper reports on safety climate factors found in clerical and service organizations in Australia. Concurrent validity studies are reported. In contradistinction to published studies, it is argued that safety climate factors are not stable across organizations. The significance of this for planning and assessing the efficacy of OH&S programs is discussed. It is concluded that although safety climate factors are not stable, the safety climate factor pattern identified in organizations provides a powerful management tool for designing OH&S programs.     

Multicriteria Analysis of the Conflicts between Rural Development Scenarios in the Gordon District,Scotland

In this paper a methodology is presented allowing the evaluation of possible development scenarios for a region against a set of environmental and other criteria on the basis of the assessment of the scenarios by local experts. The methodology starts with the pairwise comparison of the scenarios by different panels of local actors and decision makers. This information is aggregated using multicriteria analysis in order to arrive at a ranking of the scenarios or to analyse the trade-offs between different groups of criteria. The methodology is explained and illustrated with an example for the Gordon District in Scotland.     

Characterization of humic-rich hydrocolloids and their metal species by means of competing ligand and metal exchange--an on-site approach

An improved on-site characterization of humic-rich hydrocolloids and their metal species in aquatic environments was the goal of the present approach. Both ligand exchange with extreme chelators (diethylenetetraaminepentaacetic acid (DTPA), ethylendiaminetetraacetic acid (EDTA)) and metal exchange with strongly competitive cations (Cu(II) were used on-site to characterize the conditional stability and availability of colloidal metal species in a humic-rich German bogwater lake (Venner Moor, Münsterland). A mobile time-controlled tangential-flow ultrafiltration technique (cut-off: 1 kDa) was applied to differentiate operationally between colloidal metal species and free metal ions, respectively. DOC (dissolved organic carbon) and metal determinations were carried out off-site using a home-built carbon analyzer and conventional ICP-OES (inductively-coupled plasma-optical emission spectrometry), respectively. From the metal exchange equilibria obtained on-site the kinetic and thermodynamic stability of the original metal species (Fe, Mn, Zn) could be characterized. Conditional exchange constants Kex obtained from aquatic metal species and competitive Cu(II) ions follow the order Mn > Zn > > Fe. Obviously, Mn and Zn bound to humic-rich hydrocolloids are very strongly competed by Cu(II) ions, in contrast to Fe which is scarcely exchangeable. The exchange of aquatic metal species (e.g. Fe) by DTPA/EDTA exhibited relatively slow kinetics but rather high metal availabilities, in contrast to their Cu(II) exchange.     

MULTICOMPONENT GEOCHEMICAL TRANSPORT MODELING USING HYDRUS-1D AND HP11

Abstract: The transport of reactive contaminants in the subsurface is generally affected by a large number of nonlinear and often interactive physical, chemical, and biological processes. Simulating these processes requires a comprehensive reactive transport code that couples the physical processes of water flow and advective-dispersive transport with a range of biogeochemical processes. Two recently developed coupled geochemical models that are both based on the HYDRUS-1D software package for variably saturated flow and transport are summarized in this paper. One model resulted from coupling HYDRUS-1D with the UNSATCHEM module. While restricted to major ion chemistry, this program enables quantitative predictions of such problems as analyzing the effects of salinity on plant growth and the amount of water and amendments required to reclaim salt-affected soil profiles. The second model, HPI, resulted from coupling HYDRUS-1D with the PHREEQC biogeochemical code. The latter program accounts for a wide range of instantaneous or kinetic chemical and biological reactions, including complexation, cation exchange, surface complexation, precipitation dissolution and/or redox reactions. The versatility of HP1 is illustrated in this paper by means of two examples: the leaching of toxic trace elements and the transport of the explosive TNT and its degradation products.     

Major hazards—Thinking the unthinkable

It is a common experience that public administrations tend to shy away from the explicit acknowledgment of quantitative risk levels. Faced with extreme concentrations of population and of industrial activities, including LPG and liquid chlorine storage, within a very small land area, Hong Kong has faced up to the issue of major man-made hazards by “thinking the unthinkable” and adopting explicit risk guidelines. This article describes how these guidelines were developed and the arguments that led to their adoption. It is emphasized that the risk guidelines are not rigid standards but simply a method of focusing decision making and ensuring that any decision to contravene the guidelines is taken at an appropriately senior level in the administration. The way in which the guidelines have been incorporated intimately into the planning and decision-making process is described and details are given on how this has led to the implementation of a variety of measures that have greatly reduced both societal and individual risk from certain types of chemical storage and chemical processing installations in Hong Kong. The opinions in this paper represent the views of the authors and not necessarily those of the Hong Kong Government.     

Rapid interphase analysis for prenatal diagnosis of translocation carriers using subtelomeric probes

Interphase fluorescence in situ hybridization (FISH) has become an accepted laboratory technique for the rapid and preliminary prenatal assessment of chromosome aneuploidy. The introduction of subtelomeric FISH probes now allows for the molecular–cytogenetic analysis of terminal chromosome rearrangements. In a prospective study, we examined the prenatal use of subtelomeric probes on interphase cells to rapidly detect the carrier status of a fetus when a parent carried a known reciprocal or Robertsonian chromosome translocation. Three of the cases were identified as being abnormal. All cases were confirmed by routine cytogenetic analysis. These findings clearly demonstrated the utility of this technique and these probes to rapidly and correctly identify balanced and unbalanced chromosome anomalies of a fetus that could result from parental translocations. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal measurement of the fetal cerebellum and cisterna cerebellomedullaris by ultrasound

The fetal cerebellum can be visualized with ultrasound throughout the second trimester. We describe a technique for measuring the transverse and anteroposterior cerebellar diameters and the measurement of the cisterna magna in the same plane between 14 and 32 weeks gestation. Nomograms for these measurements against gestational age showed good correlation, and narrow confidence limits for the transverse cerebellar diameter. The transverse cerebellar diameter was also measured directly in 79 fetuses after mid-trimester abortion and the measurements obtained were compared with the ultrasound TCD nomogram. Good correlation, was obtained between the post mortem measurements and the ultrasound TCD nomogram. Routine use of these measurements and nomograms should prove valuable in the diagnosis of congenital abnormality of the posterior fossa and may also be of use in assessing the effect of severe intrauterine growth retardation and other insults on cerebellar growth and development. The narrow confidence limits obtained with the TCD nomogram should enable it to be used with confidence in clinical practice.     

Effectiveness of mandatory license testing for older drivers in reducing crash risk among urban older Australian drivers

Most licensing jurisdictions in Australia maintain mandatory assessment programs targeting older drivers, whereby a driver reaching a specified age is required to prove his or her fitness to drive through medical assessment and/or on-road testing. Previous studies both in Australia and elsewhere have consistently failed to demonstrate that age-based mandatory assessment results in reduced crash involvement for older drivers. However studies that have based their results upon either per-population or per-driver crash rates fail to take into account possible differences in driving activity. Because some older people maintain their driving licenses but rarely if ever drive, the proportion of inactive license-holders might be higher in jurisdictions without mandatory assessment relative to jurisdictions with periodic license assessment, where inactive drivers may more readily either surrender or lose their licenses. The failure to control for possible differences in driving activity across jurisdictions may be disguising possible safety benefits associated with mandatory assessment. The current study compared the crash rates of drivers in Melbourne, Australia, where there is no mandatory assessment and Sydney, Australia, where there is regular mandatory assessment from 80 years of age onward. The crash rate comparisons were based on four exposure measures: per population, per licensed driver, per distance driven, and per time spent driving. Poisson regression analysis incorporating an offset to control for inter-jurisdictional road safety differences indicated that there was no difference in crash risk for older drivers based on population. However drivers aged 80 years and older in the Sydney region had statistically higher rates of casualty crash involvement than their Melbourne counterparts on a per license issued basis (RR: 1.15, 1.02-1.29, p=0.02) and time spent driving basis (RR: 1.19, 1.06-1.34, p=0.03). A similar trend was apparent based on distance travelled but was of borderline statistical significance (RR: 1.11, 0.99-1.25, p=0.07). Collectively, it can be inferred from these findings that mandatory license re-testing schemes of the type evaluated have no demonstrable road safety benefits overall. Further research to resolve this on-going policy debate is discussed and recommended.