Natural abundance of stable carbon and nitrogen isotopes in Cannabis sativa reflects growth conditions

Stable carbon and nitrogen isotope signatures (delta C-13 and delta N-15) of Cannabis sativa were assessed for their usefulness to trace seized Cannabis leaves to the country of origin and to source crops by determining how isotope signatures relate to plant growth conditions. The isotopic composition of Cannabis examined here covered nearly the entire range of values reported for terrestrial C-3 plants. The delta C-13 values of Cannabis from Australia, Papua New Guinea and Thailand ranged from -36 to -25 parts per thousand, and delta N-15 values ranged from -1.0 to 15.8 parts per thousand. The stable isotope content did not allow differentiation between Cannabis originating from the three countries, but delta C-13 values of plantation-grown Cannabis differed between well-watered plants (average delta C-13 of -30.0 parts per thousand) and plants that had received little irrigation (average delta C-13 of -26.4 parts per thousand). Cannabis grown under controlled conditions had delta C-13 values of -32.6 and -30.6 parts per thousand with high and low water supply, respectively. These results indicate that water availability determines leaf C-13 in plants grown under similar conditions of light, temperature and air humidity. The delta C-13 values also distinguished between indoor- and outdoor-grown Cannabis; indoor- grown plants had overall more negative delta C-13 values (average -31.8 parts per thousand) than outdoor-grown plants (average -27.9 parts per thousand). Contributing to the strong C-13-depletion of indoor- grown plants may be high relative humidity, poor ventilation and recycling of C-13-depleted respired CO2. Mineral fertilizers had mostly lower delta N-15 values (-0.2 to 2.2 parts per thousand) than manure-based fertilizers (7.6 to 22.7 parts per thousand). It was possible to link delta N-15 values of fertilizers associated with a crop site to soil and plant delta N-15 values. The strong relationship between soil, fertilizer, and plant delta N-15 suggests that Cannabis delta N-15 is determined by the isotopic composition of the nitrogen source. The distinct delta N-15 values measured in Cannabis crops make delta N-15 an excellent tool for matching seized Cannabis with a source crop. A case study is presented that demonstrates how delta C-13 and delta N-15 values can be used as a forensic tool.

Olfaction in the Queensland fruit fly, Bactrocera tryoni. I: Identification of olfactory receptor neuron types responding to environmental odors

The electroantennogram method was used to investigate the number of distinct olfactory receptor neuron types responding to a range of behaviorally active volatile chemicals in gravid Queensland fruit flies, Bactrocera tryoni. Three receptor neuron types were identified. One type responds to methyl butyrate, 2-butanone, farnesene, and carbon dioxide; a second to ethanol; and a third to n-butyric acid and ammonia. The receptor neuron type responding to methyl butyrate, 2-butanone, farnesene, and carbon dioxide consists of three subtypes. The presence of a limited number of receptor neuron types responding to a diverse set of chemicals and the reception of carbon dioxide by a receptor neuron type that responds to other odorants are novel aspects of the peripheral olfactory discrimination process.

Assessing ecological impacts of shrimp and sewage effluent: Biological indicators with standard water quality analyses

Despite evidence linking shrimp farming to several cases of environmental degradation, there remains a lack of ecologically meaningful information about the impacts of effluent on receiving waters. The aim of this study was to determine the biological impact of shrimp farm effluent, and to compare and distinguish its impacts from treated sewage effluent. Analyses included standard water quality/sediment parameters, as well as biological indicators including tissue nitrogen (N) content, stable isotope ratio of nitrogen (delta N-15) and amino acid composition of inhabitant seagrasses, mangroves and macroalgae. The study area consisted of two tidal creeks, one receiving effluent from a sewage treatment plant and the other from an intensive shrimp farm. The creeks discharged into the western side of Moreton Bay, a sub-tropical coastal embayment on the east coast of Australia. Characterization of water quality revealed significant differences between the creeks, and with unimpacted eastern Moreton Bay. The sewage creek had higher concentrations of dissolved nutrients (predominantly NO3-/NO2- and PO43-, compared to NH4+ in the shrimp creek). In contrast, the shrimp creek was more turbid and had higher phytoplankton productivity. Beyond 750 m from the creek mouths, water quality parameters were indistinguishable from eastern Moreton Bay values. Biological indicators detected significant impacts up to 4 km beyond the creek mouths (reference site). Elevated plant delta N-15 values ranged from 10.4-19.6 parts per thousand at the site of sewage discharge to 2.9-4.5 parts per thousand at the reference site. The free amino acid concentration and composition of seagrass and macroalgae was used to distinguish between the uptake of sewage and shrimp derived N. Proline (seagrass) and serine (macroalgae) were high in sewage impacted plants and glutamine (seagrass) and alanine (macroalgae) were high in plants impacted by shrimp effluent. The delta N-15 isotopic signatures and free amino acid composition of inhabitant flora indicated that sewage N extended further from the creek mouths than shrimp N. The combination of physical/chemical and biological indicators used in this study was effective in distinguishing the composition and subsequent impacts of aquaculture and sewage effluent on the receiving waters. (C) 2001 Academic Press.

Influence of fungal pathogens and environmental conditions on disease severity, flower fall and desiccation of harvested Geraldton waxflower - 2. Studies with commercial packages

Relationships were examined between environmental conditions mediated by packaging and handling and the deterioration of harvested Geraldton waxflower cv. 'Fortune Cookie'. Disease severity plus flower and leaf drop caused by inoculation with Botrytis cinerea were reduced by lowering handling temperatures to 0, 5 or 5/20 degreesC alternated daily, versus 20 degreesC. They were also reduced by inhibition of ethylene action with a silver thiosulfate pulse pretreatment. Additionally, treatments that enhanced water loss, such as packing dry, keeping forced air-cooling holes open and strategic placement of extra ventilation holes may also reduce disease severity and flower plus leaf fall. Inclusion of KMnO4-based Bloomfresh ethylene scrubbing sachets in packages did not reduce disease severity or lessen flower plus leaf fall. Thus, deterioration of waxflower packaged in commercial cartons can be minimised by keeping temperatures low, packing plant material dry, use of cartons with strategically placed ventilation holes and/or pretreatment with silver thiosulfate.

Globalisation and sustainability: environmental Kuznets curve and the WTO

Economic globalisation is seen by many as a driving force for global economic growth. Yet opinion is divided about the benefits of this process, as highlighted by the WTO meeting in Seattle in late 1999. Proponents of economic globalisation view it as a positive force for environmental improvement and as a major factor increasing the likelihood of sustainable development through its likely boost to global investment. These proponents mostly appeal to analysis based on the environmental Kuznets curve (EKC) to support their views about environmental improvement. But EKC-analysis has significant deficiencies. Furthermore, it is impossible to be confident that the process of economic globalisation will result in sustainable development, if 'weak conditions' only are satisfied. 'Strong conditions' probably need to be satisfied to achieve sustainable development, and given current global institutional arrangements, these are likely to be violated by the economic globalisation process. Global political action seems to be needed-to avert a deterioration in the global environment and to prevent unsustainability of development. This exposition demonstrates the limitations of EKC-analysis, identifies positive and negative effects of economic globalisation on pollution levels, and highlights connections between globalisation and the debate about whether strong or weak conditions are required for sustainable development. The article concludes with a short discussion of the position of WTO in relation to trade and the environment and the seemingly de facto endorsement of WTO of weak conditions for sustainable development. It suggests that WTO's relative neglect of environmental concerns is no longer politically tenable and needs to be reassessed in the light of recent developments in economic analysis. The skew of economic growth, e.g. in favour of developing countries, is shown to be extremely important from a global environmental perspective. (C) 2001 Elsevier Science B.V. All rights reserved.

Why farmers continue to use pesticides despite environmental, health and sustainability costs

Use of chemical inputs such as pesticides has increased agricultural production and productivity. However, negative externalities from such use have increased too. These externalities include damage to agricultural land, fisheries, fauna and flora. Another major externality is the unintentional destruction of beneficial predators of pests thereby increasing the virulence of many species of agricultural pests. Furthermore, increased mortality and morbidity of humans due to exposure to pesticides are recorded especially in developing countries. The costs from these externalities are large and affect farmers' returns. However, despite these high costs, farmers continue to use pesticides and in most countries in increasing quantities. In this paper, we examine this paradox and show why farmers continue to use pesticides despite the increasing costs. We also emphasize 'lock-in' aspects of pesticide use. (C) 2001 Elsevier Science B.V. All rights reserved.

A new approach for detecting and mapping sewage impacts

Increased nitrogen loading has been implicated in eutrophication occurrences worldwide. Much of this loading is attributable to the growing human population along the world's coastlines. A significant component of this nitrogen input is from sewage effluent, and delineation of the distribution and biological impact of sewage-derived nitrogen is becoming increasingly important. Here, we show a technique that identifies the source, extent and fate of biologically available sewage nitrogen in coastal marine ecosystem. This method is based on the uptake of sewage nitrogen by marine plants and subsequent analysis of the sewage signature (elevated delta N-15) in plant tissues. Spatial analysis is used to create maps of delta N-15 and establish coefficient of variation estimates of the mapped values. We show elevated delta N-15 levels in marine plants near sewage outfalls in Moreton Bay, Australia, a semi-enclosed bay receiving multiple sewage inputs. These maps of sewage nitrogen distribution are being used to direct nutrient reduction strategies in the region and will assist in monitoring the effectiveness of environmental protection measures. (C) 2001 Elsevier Science Ltd. All rights reserved.

Environmental regulation of land use and public compensation: principles, and Swiss and Australian examples

The authors discuss the regulation of rural land use and compensation for property-rights restrictions, both of which appear to have become more commonplace in recent years but also more contested. The implications of contemporary theories in relation to this matter are examined, including: the applicability of new welfare economics; the relevance of the neoclassical theory of politics; and the implications of contemporary theories of social conflict resolution and communication. Examination of examples of Swiss and Australian regulation of the use of rural properties, and the ensuing conflicts, reveals that many decisions reflect a mixture of these elements. Rarely, if ever, are social decisions in this area made solely on the basis of welfare economics, for instance social cost-benefit analysis. Only some aspects of such decisions can be explained by the neoclassical theory of politics. Theories of social conflict resolution suggest why, and in what way, approaches of discourse and participation may resolve conflicts regarding regulation and compensation. These theories and their practical application seem to gain in importance as opposition to government decisions increases. The high degree of complexity of most conflicts concerning regulation and compensation cannot be tackled with narrow economic theories. Moreover, the Swiss and Australian examples show that approaches involving conflict resolution may favour environmental standards.

The limits of environmental responsibility - A stormwater case study

The motivation for concern about the environment beyond one's neighborhood is still relatively poorly understood. This article examines the determinants of feelings of responsibility at a regional watershed level. Using demographic, attitudinal, self-reported behavior and neighborhood mapping measures from four cities in Australia, five hypotheses were derived. These were that wider environmental concerns would depend on (a) the physical and social characteristics of the respondents' neighborhoods, (b) the size of their perceived neighborhoods, (c) the length of residence at their localities, (d) educational level and attitudes toward environmental moral responsibility (and the interaction between them), and (e) the level of reported environmentally friendly behavior. Support was gained for all hypotheses except length of residence and the role of general moral attitudes toward the environment. It is concluded that to explain community action at the regional level, it is important to include both spatial and psychological insights and methodologies in research.