A COLORIMETRIC METHOD FOR THE DETERMINATION OF TRACE COPPER CONCENTRATIONS IN WATER1

Trace quantities of copper (II) ion can be found in natural water as waste products from industrial, mining, and agricultural operations. Because low concentrations of copper can be toxic to plant life, many workers have devised methods of analysis for this metal in water. These methods require expensive equipment and skilled technicians. The described study illustrates a simple method in which copper (II) ion is concentrated by a batch ion exchange technique and estimated colorimetrically after formation of the blue triethylenetetramine complex. Using the visible absorption peak of the complex at 600 nm it was possible to obtain accurate estimations of original copper concentrations in the range 0.5-3 ppm. Using the complex absorption peak at 260 nm in the ultra-violet region of the spectrum increased the sensitivity by a factor of twenty. Because of the dependence of the complex formation reaction on solution acidity it is possible to optimize conditions for the detection of copper (II) in the presence of other metal ions. This type of method, which could be extended to the analysis of other metal ions, could be performed by a relatively unskilled technician under field conditions.     

Eu3+ uptake by calcite: preliminary results from coprecipitation experiments and observations with surface-sensitive techniques

A lack of information in databases for contamination risk assessment about the transport behaviour of the trivalent f-orbital elements in groundwater systems where calcite is at equilibrium motivated this study of Eu(3+) uptake. The free drift technique was used to examine the effects of Eu(3+) concentration, presence of Na(+) or K(+) and temperature, as well as calcite nucleation and precipitation kinetics, on the partitioning of calcite. Changes in surface composition and morphology resulting from exposure of single crystals of Iceland spar to Eu(3+)-bearing solutions were observed with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). First results confirm that calcite has high affinity for Eu(3+). Rates of nucleation and precipitation strongly affect the extent of uptake but the presence of Na(+) and K(+) has no effect, suggesting formation of solid solution as CaCO(3)-EuOHCO(3). Surface-sensitive techniques prove that Eu(3+) is adsorbed to calcite even when the surface is dissolving and adsorption is not accompanied by precipitation of a separate Eu(3+)-solid phase. Adsorbed Eu modifies calcite's dissolution behaviour, roughening terraces and rounding step edges, and producing surface morphology where some surface sites appear blocked. Results imply that Eu(3+) concentrations in natural calcites are limited by Eu(3+) availability rather than by a lack of ability to fit into calcite's atomic structure. This behaviour can probably be expected for other trivalent rare Earth elements (REE), actinides and fission products whose behaviour is similar to that of Eu(3+). These elements are likely to be incorporated within the calcite bulk in systems where it is precipitating and the demonstrated strong partitioning ensures some uptake even where calcite is at or under saturation.     

The identification and classification of reactions to sexual harassment

Distinct forms of reactions to sexual harassment were identified in the current study, and a classification scheme was developed based upon those reactions. One hundred forty two male and 100 female upper-division undergraduate management students and 44 working women read 18 randomly ordered scenarios, each of which depicted a woman being exposed to a different form of sexual harassment by a man. For each incident, the subjects were asked to write down what they themselves would do if they were in the woman's place. The resulting 5148 open-ended responses were systematically sorted into 10 classes of reaction types. In addition to assessing the reliability and validity of the classification scheme, the relative frequency of employment of the various classes was examined. Comparisons of the reactions of men and women students and comparisons of the reactions of working women and women students yielded few significant differences.     

Current approaches to the revegetation and reclamation of metalliferous mine wastes

Abandoned metalliferous mine wastes can result in severe pollution and have aesthetic impacts on the local environment. Use of a vegetation cover gives a cost-effective and environmentally sustainable method of stabilising and reclaiming wastes such as mine-spoils and tailings. Many characteristics of metalliferous wastes are often inimical to successful vegetation establishment, most notably phytotoxic levels of residual heavy metals, low nutrient status and poor physical structure of the substratum. Current approaches to revegetation and reclamation involve both ameliorative and adaptive strategies to allow plant establishment and encourage subsequent vegetation development. Different techniques of revegetation are available for temperate and arid, subtropical regions depending on the characteristics of the waste. These include direct seeding with commercially available plants, use of cover and barrier systems and the enhancement of natural revegetation processes.     

Restoration Scaling Approaches to Addressing Ecological Injury: The Habitat-Based Resource Equivalency Method

Environmental Management - Natural resource trustee agencies must determine how much, and what type of environmental restoration will compensate for injuries to natural resources that result from...     

A Critical Review of Assumptions About the Prairie Dog as a Keystone Species

Cynomys spp.) have been labeled as keystone species because of their influence on biological diversity and ecosystem function. However, the validity of several assumptions used to support keystone status is questionable. We review the strength of the evidence and the magnitude of the prairie dog's effects on ecosystem structure and function. We use this review to reevaluate the keystone role for prairie dogs. Our goal is to encourage sound management of the prairie dog ecosystem by improving the ecological foundation of their keystone status. Our review confirms that prairie dogs affect a number of ecosystem-level functions but that their influence on prairie vertebrates may be less than previously suggested. Species richness and abundance patterns were variable among plants, mammals, and birds and were not consistently higher on prairie dog colonies compared to uncolonized areas. In addition, only nine of the 208 species listed in the literature as observed on or near prairie dogs colonies had quantitative evidence of dependence on prairie dogs. Abundance data indicated opportunistic use of colonies for an additional 20 species. A total of 117 species may have some relationship with prairie dogs, but we lacked sufficient data to evaluate the strength of this relationship. The remaining 62 species may be accidental or alien to the system. Despite our conclusion that some prairie dog functions may be smaller than previously assumed, collectively these functions are quite large compared to other herbivores in the system. We suggest that prairie dogs also provide some unique functions not duplicated by any other species and that continued decline of prairie dogs may lead to a substantial erosion of biological diversity and landscape heterogeneity across prairie and shrub-steppe landscapes. Thus, we concur that keystone status for prairie dogs is appropriate and may aid conservation efforts that help protect species dependent on prairie dogs and support other important ecosystem functions.     

Evaluation of interventions to make top tether hardware more visible during child restraint system (CRS) installations

Objectives: The objective of the study is to determine whether specific child restraint system (CRS) or vehicle conditions improve top tether attachment rates during volunteer installations.

Methods: A factorial randomized controlled trial was designed to evaluate 4 different experimental categories: (1) Color of tether adjuster casing (black or red), (2) labeling on tether adjuster casing (labeled with “Tether: Use for forward-facing” or unlabeled), (3) storage location of tether (bundled in a rubber band on the back of CRS or Velcroed over the forward-facing belt path), and (4) labeling in vehicle (labeled under head restraint and below anchor or unlabeled). Ninety-six volunteers were randomly assigned to one combination of conditions. One installation per volunteer was completed. The primary outcome measure was acceptable attachment of the top tether to the tether anchor. The secondary outcome measure was overall secureness of the installation. Pearson’s chi-square tests were used to identify significant predictors of acceptable outcomes and logistic regression was used to investigate interaction effects.

Results: A total of 66/96 subjects (68.8%) attached the top tether in an acceptable manner, with either zero errors (n?=?50) or minor errors (n?=?16). A total of 30/96 subjects (31.2%) had unacceptable tether outcomes, with either major errors (n?=?10) or nonuse the tether at all (n?=?20). None of the 4 experimental categories significantly affected tether outcomes. Subjects who opted to install the CRS with the lower anchors (LAs) had higher rates of acceptable tether attachment compared to subjects who installed using the seat belt or those who used both LA and seat belt together (χ² = 6.792, P = .034). Tether outcomes were not correlated with previous CRS experience, use of instruction manual(s), age, or sex. Only 15.6% of subjects produced overall correct and tight installations. Of those who used the seat belt in some manner, 70.2% neglected to switch the retractor into locking mode.

Conclusions: Conditions in this study including tether color, tether labeling, storage location, and vehicle labeling did not significantly affect tether attachment rates. High rates of tether misuse and nonuse warrant further exploration to find effective solutions to this usability problem.     

Toxic equivalency factors for PAH and their applicability in shellfish pollution monitoring studies

Fish and shellfish are exposed to a wide range of polycyclic aromatic hydrocarbons (PAH) following oil spills at sea, and can become contaminated as a result. Finfish have a more effective mixed-function oxidase enzyme system than shellfish, and are therefore able to metabolise and excrete PAH more effectively than the invertebrates. Thus, contamination by high-molecular weight PAH, including those with carcinogenic potential and so of concern with regard to human consumers, is therefore usually observed in shellfish, and particularly in bivalve molluscs. Oil spills are not the sole source of PAH, however, as parent compounds are also generated by a wide range of combustion processes. In this paper, consideration is given to monitoring data gathered following recent oil spills (both of crude oil and diesel fuel), alongside data from other studies. These include studies conducted around a former gasworks site and downstream of an aluminium smelter in the UK, and from mussel monitoring studies undertaken in the UK and the USA (including the Exxon Valdez oil spill and the National Status and Trends programme), and in other countries in Europe. For comparative purposes the PAH concentrations are summed and also expressed as benzo[a]pyrene equivalents, their relative concentrations being weighted in relation to the carcinogenic potential of individual PAH compounds using toxic equivalency factors (TEF). Our aim was to assess the utility of this approach in fishery resource monitoring and control following oil spills. Certainly this approach seems useful from the data assessed in this study. and the relative ranking of the various studies seems to reflect the relative degree of concern for human consumers due to the differing contamination sources. As a simple tool for control purposes it is equally applicable to PAH derived from oil spills, and from industrial and combustion sources.     

No net loss for people and biodiversity

Governments, businesses, and lenders worldwide are adopting an objective of no net loss (NNL) of biodiversity that is often partly achieved through biodiversity offsetting within a hierarchy of mitigation actions. Offsets aim to balance residual losses of biodiversity caused by development in one location with commensurate gains at another. Although ecological challenges to achieve NNL are debated, the associated gains and losses for local stakeholders have received less attention. International best practice calls for offsets to make people no worse off than before implementation of the project, but there is a lack of clarity concerning how to achieve this with regard to people's use and nonuse values for biodiversity, especially given the inevitable trade-offs when compensating biodiversity losses with gains elsewhere. This is particularly challenging for countries where poor people depend on natural resources. Badly planned offsets can exacerbate poverty, and development and offset impacts can vary across spatial-temporal scales and by location, gender, and livelihood. We conceptualize the no-worse-off principle in the context of NNL of biodiversity, by exploring for whom and how the principle can be achieved. Changes in the spatial and temporal distribution of biodiversity-related social impacts of a development and its associated offset can lead to social inequity and negatively impact people's well-being. The level of aggregation (regional, village, interest group, household, and individual) at which these social impacts are measured and balanced can again exacerbate inequity in a system. We propose that a determination that people are no worse off, and preferably better off, after a development and biodiversity offset project than they were before the project should be based on the perceptions of project-affected people (assessed at an appropriate level of aggregation); that their well-being associated with biodiversity losses and gains should be at least as good as it was before the project; and that this level of well-being should be maintained throughout the project life cycle. Employing this principle could help ensure people are no worse off as a result of interventions to achieve biodiversity NNL.