A review of source tracking techniques for fine sediment within a catchment

Excessive transport of fine sediment, and its associated pollutants, can cause detrimental impacts in aquatic environments. It is therefore important to perform accurate sediment source apportionment to identify hot spots of soil erosion. Various tracers have been adopted, often in combination, to identify sediment source type and its spatial origin; these include fallout radionuclides, geochemical tracers, mineral magnetic properties and bulk and compound-specific stable isotopes. In this review, the applicability of these techniques to particular settings and their advantages and limitations are reviewed. By synthesizing existing approaches, that make use of multiple tracers in combination with measured changes of channel geomorphological attributes, an integrated analysis of tracer profiles in deposited sediments in lakes and reservoirs can be made. Through a multi-scale approach for fine sediment tracking, temporal changes in soil erosion and sediment load can be reconstructed and the consequences of changing catchment practices evaluated. We recommend that long-term, as well as short-term, monitoring of riverine fine sediment and corresponding surface and subsurface sources at nested sites within a catchment are essential. Such monitoring will inform the development and validation of models for predicting dynamics of fine sediment transport as a function of hydro-climatic and geomorphological controls. We highlight that the need for monitoring is particularly important for hilly catchments with complex and changing land use. We recommend that research should be prioritized for sloping farmland-dominated catchments.     

Mitochondrial DNA sequence variation in spiny lobsters: population expansion,panmixia, and divergence

To investigate population differentiation in a comparative and historical context, segments of the mitochondrial cytochrome c oxidase subunit I gene and the control region were sequenced in Panulirus argus from nine sites along approximately 1,500 km of the Northern Caribbean Sea (n = 326) and analyzed with respect to available panulirid data. A mismatch analysis and Fu’s F _S test uncovered a signature of historical population expansion around the time of the Last Glacial Maximum. Significant population structure was not detected in the area. The data supported a hypothesis of panmixia resulting from ongoing larval transport by ocean currents and historical population expansion. Despite high intraspecific divergence levels at COI within Panulirus argus and several other Panulirus species, genetic species identification through DNA barcoding was feasible using either a modified distance threshold or a character-based approach.     

Facilitating Sediment Budget Construction for Land Management Applications

Sediment budgets describe the production, transport, deposition and export of sediment in a catchment, and thus provide information useful for planning soil conservation, restoration and monitoring programmes and for evaluating existing and future environmental impacts. Five examples from New Zealand illustrate a variety of sediment budgeting approaches and their use in achieving goals relevant to land-use planning and management. Appropriate sediment budgeting strategies can be selected for a particular application only through careful consideration of the kinds of decisions that will follow from budgeting results. Sediment budget projects can be designed to incorporate the close co-operation between technical experts and clients that results in the most useful sediment budgets.     

Low or absent unconjugated estriol in pregnancy: an indicator for steroid sulfatase deficiency detectable by fluorescence in situ hybridization and biochemical analysis

It has been previously reported that a low or absent maternal serum unconjugated estriol (uE3) level is associated with placental steroid sulfatase (STS) deficiency. Here we report a correlation between patients who present with a very low or absent maternal serum uE3 and a deletion of the STS gene as assessed by fluorescence in situ hybridization (FISH). We studied nine prenatal cases that presented to the clinical laboratory with an abnormal triple screen, specifically low or absent maternal serum uE3 and a 46,XY karyotype. FISH analysis showed complete deletion of a probe containing the STS gene in six cases and one case had a partial deletion (reduced but not absent signal). The remaining two cases were not deleted for the STS probe. All mothers tested whose fetus showed a deletion were shown to be STS deletion carriers using FISH. Biochemical analysis was performed on 7/9 prenatal specimens. All fetuses deleted for the STS probe were also found to be deficient for STS by biochemical analysis of cultured amniotic fluid (5/5). Of the two fetuses not deleted for the STS probe, one was deficient for STS activity, while the other had a normal result. The abnormal result of enzyme deficiency by biochemical analysis in a non-deletion case likely represents a mutation in the STS gene, not detectable by this FISH assay. Postnatal FISH confirmation of the STS deletion was performed in 1/7 cases. Clinical follow-up was available for 4/9 cases following birth. Copyright © 2002 John Wiley & Sons, Ltd.     

The development of new environmental policies and processes in response to a crisis: the case of the multiple barrier approach for safe drinking water

While new environmental policies and procedures often are developed incrementally, they can also result from crises or other significant events. In situations where policies and procedures are introduced in response to a crisis, questions about the strengths and weaknesses of existing mechanisms, and the extent to which they can be used to address concerns, may be ignored. This paper explores the complexities of introducing new policies and processes where planning systems and procedures already exist. Drinking water source protection policies that are being developed in response to the tragic events in Walkerton, Ontario, Canada serve as the context for the inquiry. Three case study watersheds were selected to reflect the diversity of municipal jurisdictions and water supply systems in Ontario. A content analysis was undertaken on regulatory and non-regulatory policy documents to determine the extent to which they addressed elements of the multi-barrier approach for drinking water safety. Findings from the research reveal considerable evidence of the multi-barrier approach in the policy and guiding documents analyzed. Policy development in response to a crisis can advance progress on the issue of drinking water safety and coincide with emerging governance strategies. Policy effectiveness may be enhanced by considering existing policies as well as contextual and jurisdictional differences.     

Earthworm assisted bioremediation of organic contaminants

Due to their biological, chemical and physical actions, earthworms can be directly employed within bioremediation strategies to promote biodegradation of organic contaminants. Earthworms have been shown to aerate and bioturbate soils and improve their nutritional status and fertility, which are variables known to limit bioremediation. Earthworms have also been shown to retard the binding of organic contaminants to soils, release previously soil-bound contaminants for subsequent degradation, and promote and disperse organic contaminant degrading microorganisms. This review discusses these earthworm actions upon the soil environment and how they might influence the fate and behaviour of soil associated organic contaminants, subsequently improving bioremediation potential. The latter part of this review considers organic compounds in the following order: agrochemicals, petroleum and crude oil hydrocarbons, PAHs and PCBs.     

Writing it down: suggestions for a new approach towards understanding pro-environmental behaviour

A fashionable field of enquiry – the relationship between expressed attitudes and actual behaviour in the context of sustainable development – is complex (Staats et al. 2004 Staats, H, Harland, P and Wilke, H. 2004. Effecting durable change: a team approach to improve environmental behaviour in the household. Environ Behav., 36(3): 341–367. [Crossref], [Web of Science ®] , [Google Scholar]) and difficult to apply in a policy-relevant manner (Aall and Norland 2005 Aall, C and Norland, I. 2005. The use of the ecological footprint in local politics and administration: results and implications from Norway. Local Environ., 10(2): 159–172. [Taylor & Francis Online] , [Google Scholar]). However, recent research indicates that the use of a household diary can be beneficial in helping to quantify household environmental impact, in educating householders about their impact, and in identifying major ‘behavioural turning points’, where householders may focus efforts to reduce their environmental impact (Hunter et al. 2006 Hunter, C, Carmichael, K and Pangbourne, K. 2006. Household ecological footprinting using a new diary-based data-gathering approach. Local Environ, 11(3): 307–327. [Taylor & Francis Online] , [Google Scholar]). In other words, the use of a diary by householders is a potentially powerful tool in encouraging and facilitating desired behavioural change. This paper reports on the initial findings of an innovative study that assessed the use of a household diary approach as a means of framing and collecting household environmental data and, critically, as an educational vehicle for bringing about behavioural change. Based on the initial findings, it is clear that there is some potential to develop practical policy measures that empower householders by allowing them to better grasp their environmental impact and, consequently, recoup positive implications in terms of financial savings (e.g. reducing the amount of food thrown out) and health benefits (e.g. more walking/cycling).     

Explaining nursing turnover intent: job satisfaction,pay satisfaction,or organizational commitment?

A number of models have been developed to explain nurses' turnover behavior. The common theme that emerges from these models is that turnover behavior is a multistage process that includes attitudinal, decisional, and behavioral components. The purpose of this study was to assess both the direct and indirect impact of certain pay policies upon the turnover intentions of paediatric nurses. The two major questions addressed were: What was the relative impact of job satisfaction, pay satisfaction, and organizational commitment upon the turnover intentions of paediatric nurses eligible for these pay policies? What model accurately portrays the relationship among these three independent variables and turnover intentions? Exploration of the causal pathways among these variables and demographic factors revealed complex models of association. The results suggest that job satisfaction has only an indirect influence on the intention to quit, whereas organizational commitment has the strongest and most direct impact. A further finding that pay satisfaction had both direct and indirect effects on turnover intent was consistent with administrators' assumptions underlying the pay policies. Control variables such as having a degree, having children, and working 12-hour shifts were found to have both direct and indirect influences upon pay satisfaction and turnover intent. © 1998 John Wiley & Sons, Ltd.     

Application of a luminescence-based biosensor for assessing naphthalene biodegradation in soils from a manufactured gas plant

Despite numerous reviews suggesting that microbial biosensors could be used in many environmental applications, in reality they have failed to be used for which they were designed. In part this is because most of these sensors perform in an aqueous phase and a buffered medium, which is in contrast to the nature of genuine environmental systems. In this study, a range of non-exhaustive extraction techniques (NEETs) were assessed for (i) compatibility with a naphthalene responsive biosensor and (ii) correlation with naphthalene biodegradation. The NEETs removed a portion of the total soil naphthalene in the order of methanol > HPCD > βCD > water. To place the biosensor performance to NEETs in context, a biodegradation experiment was carried out using historically contaminated soils. By coupling the HPCD extraction with the biosensor, it was possible to assess the fraction of the naphthalene capable of undergoing microbial degradation in soil.