ABSTRACT The limnology of a 1.9-ha storm-water detention pond is described. The eutrophic nature of this impoundment is attributed to the nutrients in runoff from the surrounding residential area. During the summer, photosynthetic activity of the phytoplankton caused surface waters to become super-saturated with oxygen, while decomposing organic material greatly reduced dissolved oxygen concentrations in the deeper water. Sediment derived from construction activity within the drainage basin caused the impoundment to be turbid. The use of road deicing salts within the drainage basin produced high chloride concentrations and a temporary meromixis during the winter and early spring. The benthic fauna consisted primarily of oligochaetes, chironomids, and chaoborids. High densities of oligochaetes were present in the settling basin. Chaoborid larvae were abundant in the deep basin where low oxygen concentrations reduced the numbers of other benthic macroinvertebrates. 相似文献
This paper describes the perceptions and misperceptions of basic alcohol and DUI-related information held by two groups of subjects: first-time DUI offenders and multiple-DUI offenders. The results revealed that both samples of subjects were well informed regarding some basic information (e.g., tolerance, elimination of alcohol from the body by the liver, effect of several drinks on increased likelihood of accident) and that the multiple-DUI offenders appeared more knowledgeable on several items (e.g., penalty for refusing breath test, beverage equivalency). These results tend to discredit the knowledge-deficit model of DUI prevention/education/rehabilitation, and an alternative coping skills model is proposed. 相似文献
Objective: Despite successes in the 1980s and early 1990s, progress in reducing impaired driving fatalities in the United States has stagnated in recent years. Since 1997, the percentage of drivers involved in fatal crashes with illegal blood alcohol concentration (BAC) levels has remained at approximately 20 to 22%. Many experts believe that public complacency, competing social and public health issues, and the lack of political fortitude have all contributed to this stagnation. The number of alcohol-related crashes, injuries, and fatalities is still unacceptable, and most are preventable. The public needs to be aware that the problem presented by drinking drivers has not been solved. Political leaders need guidance on which measures will affect the problem, and stakeholders need to be motivated once again to implement effective strategies.
Methods: The National Academy of Sciences (NAS) Transportation Research Board (TRB), Alcohol, Other Drugs, and Transportation Committee (ANB50) sponsored a workshop held at the NAS facility in Woods Hole, Massachusetts, on August 24–25, 2015, to discuss the lack of progress in reducing impaired driving and to make recommendations for future progress. A total of 26 experts in research and policy related to alcohol-impaired driving participated in the workshop. The workshop began by examining the static situation in the rate of alcohol-impaired driving fatal crashes to determine what factors may be inhibiting further progress. The workshop then discussed 8 effective strategies that have not been fully implemented in the United States. Workshop participants (16 of the 26) rated their top 3 strategies.
Results: 3 strategies received the most support: 1. Impose administrative sanctions for drivers with BACs = 0.05 to 0.08 g/dL.
2. Require alcohol ignition interlocks for all alcohol-impaired driving offenders. 3. Increase the frequency of sobriety checkpoints, including enacting legislation to allow them in the 11 states that currently prohibit them.
5 other important strategies included the following: (1) increase alcohol taxes to raise the price and reduce alcohol consumption; (2) reengage the public and raise the priority of impaired driving; (3) lower the illegal per se BAC limit to 0.05 for a criminal offense; (4) develop and implement in-vehicle alcohol detection systems; and (5) expand the use of screening and brief interventions in medical facilities.
Conclusions: Each of these strategies is proven to be effective, yet all are substantially underutilized. Each is used in some jurisdictions in the United States or Canada, but none is used extensively. Any one of the 3 strategies implemented on a widespread basis would decrease impaired driving crashes, injuries, and fatalities. Based on the research, all 3 together would have a substantial impact on the problem. 相似文献
A Tier I Sediment Ecological Risk Assessment of profundal lake sediment contaminated by diffuse pollution of heavy metals and POPs deposited from the atmosphere was completed. The concentrations of seven heavy metals and four groups of POPs (OCs, PCBs, PAHs, PBDEs) were determined in the profundal sediment of ten lakes in the United Kingdom and two sediment toxicity tests completed (chironomid survival and emergence and cladoceran survival and reproduction). The results showed that around half the lakes are at least moderately contaminated by Pb, Zn, Cd, As and PAHs deposited from the atmosphere and the toxicity quotient suggests that the contaminants of concern are Pb, As and PAHs, and not the other metals nor OCs and PCBs. There was toxicity in the sediment of four of the lakes. The Probable Effect Concentration Quotient values indicated that metals in the sediments of Scoat Tarn, Agden Reservoir and Llyn Llagi were likely to be responsible for the laboratory toxicity found in these lakes, with PAHs also contributing in Agden Reservoir. 相似文献
Within the tropical and subtropical oceans, tuna forage opportunistically on a wide variety of prey. However, little is known
about the trophic ecology of the smallest size classes which play an important role in stock assessments and fisheries management.
The foraging behavior of yellowfin tuna, Thunnus albacares (23.5–154.0 cm FL), collected from nearshore Fish Aggregating Devices (FADs) around Oahu was studied using stable isotope
and stomach contents analyses. Emphasis was placed on small juveniles. Yellowfin tuna changed their diets significantly between
45 and 50 cm forklength (ca. 1.5 kg). Smallest size classes fed on planktonic organisms inhabiting the shallow mixed layer,
primarily larval stomatopod and decapod crustaceans, whereas larger tuna fed on teleosts and adult Oplophorus gracilirostris, a vertically migrating mesopelagic species of shrimp. When interpreting the variation in prey δ15N values, we considered both their relative trophic position and δ15N values of the nitrogen at the base of the food web. Based on the distinct diet shift of the yellowfin tuna, demonstrated
by both isotope and stomach content analyses, we propose a critical mass threshold was reached at about 45 cm FL that enabled
sufficient endothermic capability to allow tuna to access prey dwelling in deeper, colder water. These ontogenetic changes
in foraging range and commensurate shift in diet of small tunas would affect their vulnerability to fishing pressure. 相似文献
The rocky intertidal mussel Mytilus californianus is exposed to potentially damaging thermal conditions during low tide. However, because the temperatures of ectothermic organisms are driven by multiple climatic factors, we do not fully understand what the body temperatures of intertidal invertebrates are under field conditions, or how thermal stress varies between intertidal sites. We designed a temperature logger that thermally matches (similar size, color, morphology and thermal inertia) living mussels of the species M. californianus, and tested its ability to provide realistic measurements of body temperature in the field. As part of these tests, we examined the propensity of M. californianus to gape, a behavior in which the mussel opens its shell valves, and which may permit evaporative cooling. Because our instruments were unable to mimic this behavior, we tested the degree to which gaping contributes to animal cooling by exposing M. californianus to a range of climatic conditions while recording body temperatures, gaping behavior and water loss. Results indicated no significant influence of gaping on body temperature. Tests comparing temperatures of loggers to those of real mussels under laboratory and field conditions showed that thermally matched loggers recorded temperatures within a few degrees of living animals and that unmodified loggers regularly incurred errors of up to 14°C. We then deployed a series of thermally matched loggers at two sites in central Oregon (Boiler Bay and Strawberry Hill) previously hypothesized to display site-specific differences in aerial temperature, and at various wave-exposure regimes within each site. Significant differences were demonstrated between sites using a subset of temperature metrics in a multivariate analysis. Yearly peaks in maximum temperature, average daily maximum temperature, and degree hours were useful in discriminating between sites. In 2001, wave-exposed sites at Strawberry Hill displayed fewer degree–hours than wave-protected sites, but an equivalent or greater maximum temperature. In 2002 both of these metrics were significantly lower in wave-exposed sites. Boiler Bay and Strawberry Hill differed in thermal regime, but not in a way that would indicate one was hotter than the other.Communicated by P.W. Sammarco, Chauvin 相似文献
This paper extends earlier work on the standards and prices approach to pollution control by considering simultaneously spatial considerations, interactive pollutants, and joint abatement costs. The form of environmental constraints appropriate to water pollution problems is discussed in detail and the implications for the standards and prices approach to water pollution control are assessed. The presence of interactive pollutants and joint abatement costs is shown to have important implications for both the theoretical properties and the implementation of the standards and prices approach. 相似文献