Determinants of consumer behavior related to organic foods

There have been many studies of what influences consumers in their decisions to purchase or consume organic foods, mainly concerned with fresh organic foods. These show a discrepancy between attitudes and behavior with people being positive about organic foods but often not purchasing them. This discrepancy seems to be explained by the fact that consumers do not consider "organically produced" to be an important purchase criterion, that organic foods are not perceived to surpass conventional foods regarding taste and shelf life (two qualities rated to be of great importance), and because of the perceived premium prices of organic foods. In two Swedish studies, health benefits were demonstrated to be more strongly related to attitudes and behavior toward organic foods than were perceived environmental benefits. A new European Union (EU) project will investigate the influences on both fresh and processed organic foods and investigate the role of moral, ethical, and affective influences on choice across eight EU countries.     

How many samples are required? Evaluating a model for verification of carbon sequestration in a hybrid poplar buffer strip

A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems.     

EVALUATION OF EROSION CONTROL PRODUCTS WITH AND WITHOUT ADDED POLYACRYLAMIDE1

ABSTRACT: Polyacrylamide (PAM) has been demonstrated to greatly reduce erosion in furrow irrigation, but much less is known about its effectiveness on the much steeper slopes typical of construction sites. The purpose of this study was to determine if anionic PAM would enhance erosion control either alone on bare soil or in combination with four types of ground covers commonly used for grass establishment: straw, straw erosion control blanket (ECB), wood fiber, and mechanically bonded fiber matrix (MBFM). Tests were conducted under natural rainfall and vegetation on a 4 percent slope (bare soil, straw, ECB, and MBFM) or using a rainfall simulator (bare soil, straw, wood fiber, MBFM) on either 10 percent or 20 percent slope on three different soil substrates. All ground cover treatments were evaluated with and without PAM applied in solution at 19 kg/ha. The straw, ECB, and MBFM significantly reduced runoff volume, average turbidity, and total sediment lost over five rainfall events on the vegetated plots. The addition of PAM to ground covers only occasionally had significant effects on runoff parameters but did significantly increase vegetative coverage overall. The rainfall simulator tests produced similar results after four events, with the straw, wood fiber, and MBFM all having significantly lower turbidity than the bare soil. The PAM significantly reduced turbidity for both the first and second events but did not consistently improve runoff quality after multiple rainfall events for any ground cover‐soil combinations tested. Separate tests of PAM applied before or after straw did not indicate a clear advantage of either approach, but runoff turbidity was often significantly reduced with PAM, especially at the 20 percent slope. Turbidity reductions were attributed to flocculation of eroded sediment.     

Control of salt laden particulate emissions from hogged fuel boilers

This paper presents the results of an evaluation of excessive salt emissions from 16 hogged fuel boilers in Washington, Oregon, and Alaska. Logs transported or stored in sea water, absorb substantial amounts of salt which is noncombustible, and is emitted as a fine particulate when the hogged fuel is burned, contributing to opacity and particulate emissions. Control measures considered are fuel pretreatment, combustion modification, use of conventional particulate control devices (electrostatic precipitators, fabric filters, and wet scrubbers), and several novel particulate control devices.The best available control technology appears to be a mechanical collector-fabric filter combination; some electrostatic scrubber type devices have also shown excellent capability.     

Preferred policies when there is a concern for probability of adoption

A theory of effective policy choice is developed that recognizes that the probability that a policy is adopted depends on who gains from it, who loses, and by how much. Ten pieces of recent environmental legislation are assessed to see how mechanisms such as coupling with other legislation, phased implementation, and the manipulation of uncertainty can spread benefits and costs. Several optimizing models are presented that explicitly incorporate the probability of adoption.     

A study of diesel emissions on Drosophila

A sex-linked recessive lethal test was performed on male fruit flies of the species Drosophila melanogaster, (Oregon-R strain), exposed to an approximate five-fold dilution of exhaust from a diesel engine. The eight hour exposure was achieved by drawing diluted diesel exhaust from a three cubic meter stainless steel exposure chamber housing laboratory animals through a two liter reaction flask modified for use with Drosophila. A preconditioned sampling bag was used to collect the emissions after passing through the exposure chamber containing the flies. Results of analyses performed on the diesel exhaust mixture showed the following: carbon dioxide—0.17%, carbon monoxide—12.2 ppm, hydrocarbons—11.6 ppm, nitrogen oxide—3.8 ppm, nitrogen dioxide—2.9 ppm, sulphur dioxide—1.0 ppm, and particulates—2.18 mg/m³. Two broods of the F₂ generation were investigated for the occurrence of recessive lethal events. These broods approximated the developing gametogenic stages of mature sperm (P₁ matings on days 2 and 3 postexposure) and spermatocytes (P₁ matings on days 8 and 9). Additionally, the F₃ generation was evaluated for the occurrence of mosaic recessive lethal events which might escape detection in the F₂ generation. An equal number of F₂ and F₃ flies for both broods served as concurrent controls. Results indicate that, under the conditions tested, the diesel exhaust did not increase the mutation frequency of the exposed flies (F₂ rate = 0.30%, F₃ rate = 0%) when compared to the concurrent controls (F₂ rate = 0.37%, F₃ rate = 0.15%).