Design of aquifer remediation systems: (1) describing hydraulic structure and NAPL architecture using tracers

Aquifer heterogeneity (structure) and NAPL distribution (architecture) are described based on tracer data. An inverse modelling approach that estimates the hydraulic structure and NAPL architecture based on a Lagrangian stochastic model where the hydraulic structure is described by one or more populations of lognormally distributed travel times and the NAPL architecture is selected from eight possible assumed distributions. Optimization of the model parameters for each tested realization is based on the minimization of the sum of the square residuals between the log of measured tracer data and model predictions for the same temporal observation. For a given NAPL architecture the error is reduced with each added population. Model selection was based on a fitness which penalized models for increasing complexity. The technique is demonstrated under a range of hydrologic and contaminant settings using data from three small field-scale tracer tests: the first implementation at an LNAPL site using a line-drive flow pattern, the second at a DNAPL site with an inverted five-spot flow pattern, and the third at the same DNAPL site using a vertical circulation flow pattern. The Lagrangian model was capable of accurately duplicating experimentally derived tracer breakthrough curves, with a correlation coefficient of 0.97 or better. Furthermore, the model estimate of the NAPL volume is similar to the estimates based on moment analysis of field data.     

Ecotypic differentiation in the marine diatom Skeletonema costatum: influence of light intensity on the photosynthetic apparatus

Three genetically distinct clones of Skeletonema costatum (Grev.) Cleve were grown at 20°C under high (274 E m^-2 s^-1) and low (27 E m^-2 s^-1) light conditions and their photoadaptive photosynthetic responses compared. When all three clones were grown under low light, pigment analyses and fluorescence excitation spectra demonstrated that the accessory pigments, chlorophyll c and fucoxanthin, became more important in light-harvesting compared to chlorophyll a. Photosynthetic unit sizes increased for Photosystems I and II in low light, but photosynthesis vs irradiance characteristics were not reliable predictors of photosynthetic unit features. Fluorescence excitation spectra and photosynthesis vs irradiance (P-I) relationships indicated that changes in energy transfer occurred independent of changes in pigment content. Large increases in accessory pigment content were not accompanied by large increases in excitation from these pigments. Changes in energy transfer properties were as important as changes in PSU size in governing the photoadaptive responses of S. costatum. When the three clones were grown under identical conditions, each had a separate and distinct pattern of photoadaptation. Significant differences among clones were found for pigment ratios, photosynthetic unit sizes for Photosystems I and II and efficiency of energy transfer between pigments. These strikingly different photoadaptive strategies among clones may partially account for the great ecological success of the diatom species. This is the first quantitative investigation of the importance of both chlorophyll c and fucoxanthin to the adaptive responses of diatoms to light intensity, and represents the most complete characterization of the photoadaptive responses of a single species of marine phytoplankter to differences in light environment.     

Ozone Exposures and Implications for Vegetation in Rural Areas of the Central Appalachian Mountains, U.S.A.

The United States is making the transition from the 1979 1 hr maximum ozone standard to the newly adopted 8 hr ozone standard (3 yr average of the 4th highest maximum 8 hr ozone concentration). Consequently, we analyzed and compared ozone concentrations under both standards from a variety of monitoring sites throughout the central Appalachian region of Kentucky (KY), West Virginia (WV), and Virginia (VA). Data from 1988-1999 were used to determine how ozone exposure between the two metrics compared for remote sites. Most sites exceeded the 1 hr standard in 1988-1990 due to the 3 yr averaging and multiple high ozone concentrations that occurred over the region in 1988. All sites were in compliance with the 1 hr standard every year after 1991. It was much more common for the ozone exposure to exceed the 8 hr standard, particularly from 1997-1999. Many sites showed exceedences beginning in 1995; Big Meadows (VA) exceeded the 8 hr standard all years except 1994 and 1996. Response of vegetation to ozone in these areas was determined using the combination of W126 values (sigmoidally weighted exposure index), the number of hours that average concentrations > or = 0.10 ppm (N100), and the presence of moderate or more extreme droughts. In general, W126 and N100 values suggested that negative vegetation growth responses over most of the 12 yr would have been minimal for most sites, even for those exceeding ozone standards. Drought-induced stomatal closures would have overridden more extreme negative growth responses at all but the Big Meadows site in 1988.     

Development of community of practice to support quantitative risk assessment for synthetic biology products: contaminant bioremediation and invasive carp control as cases

Synthetic biology has the potential for a broad array of applications. However, realization of this potential is challenged by the paucity of relevant data for conventional risk assessment protocols, a limitation due to to the relative nascence of the field, as well as the poorly characterized and prioritized hazard, exposure, and dose–response considerations associated with the development and use of synthetic biology-derived organisms. Where quantitative risk assessment approaches are necessarily to fulfill regulatory requirements for review of products containing genetically modified organisms, this paper reviews one potential avenue for early-stage quantitative risk assessment for biosafety considerations of synthetic biology organism deployment into the environment. Building from discussion from a March 2018 US Army Engineer Research and Development Center workshop on developing such quantitative risk assessment for synthetic biology, this paper reviews the findings and discussion of workshop participants. This paper concludes that, while synthetic biology risk assessment and governance will continue to refine and develop in the coming years, a quantitative framework that builds from existing practice is one potentially beneficial option for risk assessors that must contend with the technology’s limited hazard characterization or exposure assessment considerations in the near term.     

Zoning and the Tasmanian commercial rock lobster fishery

In this paper, the island of Tasmania is considered as a government jurisdiction. Management at this scale can conflict with sustainability in local environments. The case used to make this argument is the Tasmanian commercial rock lobster fishery. Within this fishery, Tasmania-wide management paradoxically intensifies differences at the same time as it effaces them. These differences contrast with Tasmania-wide management claims regarding sustainability. Actor–network theory is used to help approach these tensions. Zoning the fishery is put forward as a way to take into account differences to produce sustainable local outcomes.     

Complex habitat boosts scallop recruitment in a fully protected marine reserve

This study investigated the effects of a fully protected marine reserve on commercially valuable scallops and benthic habitats in Lamlash Bay, Isle of Arran, United Kingdom. Dive surveys found the abundance of juvenile scallops to be greater within the marine reserve than outside. A novel multivariate approach, based upon neural networks and generalised linear models, revealed the greater abundance of juveniles to be related to the greater presence of macroalgae and maerl within the reserve boundaries. This complex habitat appeared to have positively encouraged spat settlement. In contrast, the density of adult scallops did not differ between the two treatments, possibly due to the short duration of protection. However, the age, size and biomass of adult scallops were significantly greater within the reserve. Overall, this study suggests that the newly created marine reserve is already providing benefits which are flowing back to species targeted by fisheries, emphasising the importance of marine reserves in ecosystem-based management of fisheries.     

Book reviews

Sustainable Cities and Sustainable Development Sustainable Cities. G. Haughton &; C. Hunter, 1994, Jessica Kingsley/Regional Studies Association, London

Sustainable Cities in Europe. P. Nijkamp &; A. Perrels, 1994, Earthscan, London ISBN 185383, £12.95

Toward Sustainable Development Concepts, Methods and Policy. J. C. J. M. van den Bergh &; J. van der Straaten, 1994, Island Press, Washington, DC, ISBN 1 55963 3492, £30.00

Just Environments: intergenerational, international and interspecies issues. David E. Cooper &; Joy A. Palmer (Eds), 1995, London, Routledge, ISBN 0 415–10336–3, pp. 199, index, £11.99

First Steps: Local Agenda 21 in practice. Stella Whittaker (Ed.), 1995, London, HMSO, 251 pp. ISBN 0 11 701871 6, £29.95

Beyond the Car: essays on the auto culture. Sue Zielinski &; Gordon Laird (Eds), 1995, Toronto, Steel Rail Publishing/Transportation Options, 191 pp. ISBN 0 88791 042 4, pbk, C$ 19.95, US$15.95     

Urban Waterfront Regeneration in the Mersey Basin,North West England

The economic decline of traditional dockland areas has released considerable areas of land for redevelopment, much of which is close to the heart of city centres. The property development industry has capitalized upon these assets to the extent that port-related redevelopmentis a common feature throughout North America and Europe. This paper explores the experience of the Mersey Basin in North West England which, under the Mersey Basin Campaign initiative, has sought to explicitly connect improvements in water quality to economic regeneration. A small survey of commercial property valuers was used to explore this relationship and revealed the importance of water in the property development process, through potential increases in value and an enhancement of the marketability of property adjacent to water. Equally, improved water quality is revealed as an important precursor to waterside economic regeneration. Here, investment must, as with the preparation of derelict and contaminated land for redevelopment, be regarded as a public good, nurturing good water quality as an asset for the benefit of future generations and as a part of realizing the full potential of waterfront regeneration.     

Ten Years On: An Empirical Analysis of UK Environmental Statement Submissions since the Implementation of Directive 85/337/EEC

Regulations to implement Directive 85/337/EEC have been in operation in the UK for over 10 years. Implementation of the amended Directive (97/11/EC) in March 1999 marked the start of a new phase in environmental impact assessment (EIA), and so a review of the impact of the original Directive upon EIA activity is timely. This paper examines the implementation of the Directive in the UK through an empirical analysis of the publication of environmental statements (ESs) between July 1988 and April 1998. ES submissions are analysed under Annexes I and II of the Directive and under the main UK regulations, and then development control decision outcomes are considered. The implications of selected legislation and policy initiatives for ES submissions are then investigated in detail for four types of project. The Directive has been a major force in stimulating the development and growth of EIA in the UK, although the interaction of policies and legislation (environmental and otherwise) can exert an important influence upon trends in ES submissions.