Teenage driving after using marijuana or drinking and traffic accident involvement

Anonymous random digit dialing telephone surveys of nearly 6000 16–19 year old respondents were conducted in Massachusetts and Upstate New York in 1979–1981. These surveys explored frequency of driving after using marijuana, driving after drinking, respondent accident involvement in the year prior to the interview, and a variety of other respondent characteristics. Frequency of driving after using marijuana and after drinking were each associated with greater accident involvement. To isolate the accident risk of driving after marijuana use, respondents who drove after drinking were excluded from a logistic regression analysis. This analysis also controlled for the distance respondents drove and several respondent demographic characteristics. Compared to respondents who did not drive after marijuana use, teenageers who drove after smoking marijuana on at least 6 occasions per month were 2.4 times more likely to be involved in traffic accidents. Those who drove after marijuana use on at least 15 occasions per month were 2.9 times more likely to have an accident.     

Response of Mercury Contamination in Fish to Decreased Aqueous Concentrations and Loading of Inorganic Mercury in a Small Stream

Approximately 250 000 kg of mercury was lost towater and soils at the U.S. Dept. of Energy Y-12 Plantin Oak Ridge, Tennessee in the 1950s and early 1960s. A creek originating within the plant receivedcontinuous inputs of waterborne mercury, predominantlyas dissolved inorganic mercury, from groundwater,streambed contamination, and sump and process waterdischarges to the contaminated storm sewer network.These produce aqueous total mercury concentrations of1–2 g L^-1 in the upper reaches of the stream,decreasing to about 0.1–0.2 g L^-1 in its lowerreaches. A program to reduce mercury concentrationsin the creek identified specific sources (buildingsumps, contaminated springwater seeps, foundationdrains, and contaminated piping) and rerouted wateraround contaminated portions of the drain system orcollected and treated mercury-contaminated waterbefore discharging it. As a result, waterbornemercury concentrations in the creek and total mercuryloading were reduced from 1.8 g L^-1 to0.6 g L^-1 and 100 to 20 g d^-1, respectively, in the last 5 yr.Mean mercury concentrations in fish nearest sourceareas in the creek headwaters decreased at roughly thesame rate as waterborne total mercury concentrationsover the past five years, but at the facility boundarydownstream the decline in mercury bioaccumulation wasmuch less. At sites 5–15 km farther downstream, nodecrease was evident. Dissolved methylmercury tendedto increase with distance downstream in a patterninverse to that noted for its dissolved inorganicmercury precursor.Improvements in water quality and modification ofweirs to allow the passage of fish have resulted inthe establishment of large populations of fish inmercury-contaminated headwater areas previously devoidof fish. It may be that the accumulation, retention,and eventual downstream transport of this reservoir ofbiologically incorporated methylmercury has acted tobuffer against expected reductions in mercury in fishat downstream sites.     

ENGINEERING A TRANSITION TO COAL

As nations seek alternatives to oil, coal promises to become one of the principal replacement fuels in the world energy system. Engineering a transition to coal and other energy sources from the current reliance on petroleum will be a difficult task requiring a significant commitment of capital, labour, materials, equipment, land and water resources. Engineering this transition to coal will be further complicated by the long lead times that are required. This paper presents an analysis of the timing and magnitude of national resources required to implement several alternative coal development programmes in the United States. Preliminary experience aimed at extending the analysis to international energy and resource relationships is also discussed. Tandis que les nations cherchent à remplacer le pétrole, le charbon est en passe de devenir un des principaux combustibles de remplacement du système énergétique mondial. Assurer une transition à partir de la dépendance actuelle du pétrole vers le charbon et d'autres sources d'énergie s'avérera être difficile et exigera des investissements importants en capitaux, main-d'oeuvre, matériaux, équipement et ressources en terrains et en eau. Effectuer cette transition vers le charbon sera de plus compliqué par les longs délais d'éxécution qui sont requis. Cet article fait l'analyse du calendrier et de l'ampleur des ressources nationales nécessaires à la mise en valeur de plusieurs programmes de rechange en matière de développement du charbon aux Etats-Unis. On y discute également une expérience préliminaire visant à intégrer l'analyse des rapports internationaux en matière d'énergie et de ressources. En la búsqueda de combustibles alternativos al petróleo, el carbón parece ser la principal alternativa dentro del sistema energético mundial. La adaptación tecnológica al carbón y otros recursos energéticos, partiendo de la dependencia actual en el petróleo, va a ser una tarea difícil que requerirá comprometer importances cantidades de capital, trabajo, equipo, terrenos y recursos de ague. Esta transición al carbón será complicada aún mas por el prolongado lapso necesario para su ejecución. Este artículo presenta un análisis de la programación en el tiempo y la magnitud de los recursos nacionales necesarios para implementar los programas alternatives de desarrollo del carbón en los Estados Unidos. Se discute también experiencias preliminares orientadas a la extensión de este análisis a las relaciones internationales en energía y recursos.     

Persistence and pathways of testosterone dissipation in agricultural soil

The persistence and pathways of dissipation of testosterone in three agricultural soils were examined in laboratory microcosm incubations at different soil moistures (1.7-39%) and temperatures (4-30 degrees C) using (14)C- and (3)H-labeled and unlabeled testosterone. Sterilized loam was also examined to assess possible abiotic pathways. Extractable (14)C decreased rapidly for all three soils at 30 degrees C with times to dissipate 50% of material (DT(50)) ranging from 8.5 to 21 h. Respired (14)CO(2) accounted for approximately 50% of the applied (14)C after 120 h. Androgenic activity of soil extracts declined faster than the extractable (14)C levels demonstrating that testosterone was not being converted to compounds with greater activity. Dissipation rates of nonvolatile, extractable (3)H in loam at 7, 15, and 39% moisture were similar, but the rate in air-dried loam (1.7% moisture) was significantly reduced. High performance liquid chromatography (HPLC) analysis of extracts of (14)C-testosterone-treated loam incubated at 30 degrees C for 6 h revealed that the (14)C was distributed among the remaining testosterone and three major metabolites (4-androstene-3,17-dione, 5alpha-androstane-3,17-dione, and 1,4-androstadiene-3,17-dione), which accounted for 48.7, 23.7, and 9.6% of the remaining (14)C, respectively. Periodic analysis of soil incubated at 23, 12, and 4 degrees C showed that the rates of testosterone dissipation and metabolite appearance and subsequent dissipation were temperature dependent with rates decreasing with decreasing temperature. In sterilized loam, 4-androstene-3,17-dione was the only metabolite detected. We conclude that testosterone is rapidly and thoroughly biodegraded in agricultural soils under a range of conditions typical of a temperate growing season and thus is unlikely to pose a long-term risk to adjacent aquatic environments.     

Methods for estimating greenhouse gases from local places

This paper reports on two efforts to develop methods for quantifying and analysing greenhouse gas emissions from local places. The International Council for Local Environmental Initiatives-Cities for Climate Protection (ICLEI-CCP) campaign and the Association of American Geographers-Global Change in Local Places (AAG-GCLP) project represent independent efforts with differing origins and objectives. There is a rich and dynamic fine structure to the causal patterns that determine the level of greenhouse gas emissions in the society. This fine structure is essentially opaque to national and state-level inventories and analyses, and yet understanding it is necessary to understanding how human communities can be organised and human enterprise structured in environmentally sustainable ways. Simplified inventory methods that account for most but not all emissions, use readily available local data and, most important, inform efforts at emission reduction are currently available for cities and could be made available for larger or more diverse local regions or areas.     

Transpiration in Black Willow Phytoremediation Plots as Determined by the Tree‐Trunk Heat Balance Method

Plant transpiration is a critical process that affects the water balance in phytoremediation plots. The desired effect is to remove contaminated water from the soils through the plant metabolism. Thus, the transpiration rate can be a major component in modeling the groundwater flow and solute transport for a phytoremediation project and ultimately can determine the time expected to achieve remedial goals. Two phytoremediation plots of black willows (Salix nigra) were planted during October 1996 over separate,shallow groundwater plumes at a site in southeastern Louisiana. Concentrations of less than 10 mg/l of the herbicide bentazon were present in the shallow groundwater. Field experiments were developed and performed during the 1998 and 1999 growing seasons to measure sap flow as an indicator of plant transpiration. The tree‐trunk heat balance method was used to measure sap flow. Sap flow was indexed to the cross‐sectional area of the stem, and the sum of the available stem area for each plot was used to calculate the monthly water use in each plot. Daily water use in the plots averaged between 6 to 13 l/day/m² during the periods tested in 1998 and 1999. By applying growth‐rate observations with the daily water use, annual water use at tree plot maturity was estimated to be 3.6×10⁶ l/year in Plot 1 and 11.39×10⁶ l/year in Plot 2. Application of these data will allow groundwater modeling to be performed to measure the effectiveness of phytoremediation and to predict closure of remediation at the test site. © 2001 John Wiley & Sons, Inc.     

Despotic, high-impact species and the subcontinental scale control of avian assemblage structure

Some species have disproportionate influence on assemblage structure, given their numbers or biomass. Most examples of such "strong interactors" come from small-scale experiments or from observations of the effects of invasive species. There is evidence that entire avian assemblages in open woodlands can be influenced strongly by individual species over very large areas in eastern Australia, with small-bodied species (< 50 g) being adversely affected. We used data from repeated surveys in 371 sites in seven districts across a region from Victoria to Queensland (> 2000 km). A series of linked Bayesian models was used to identify large-bodied (> or = 50 g) bird species that were associated with changes in occurrence and abundance of small-bodied species. One native species, the Noisy Miner (Manorina melanocephala; family Meliphagidae), was objectively identified as the sole large-bodied species having similar detrimental effects in all districts, depressing occurrence of 57 of 71 small-bodied species. Adverse effects on abundances of small-bodied species were profound when the Noisy Miner occurred with mean site abundances > or = 1.6 birds/2 ha. The Noisy Miner may be the first species to have been shown to influence whole-of-avifauna assemblage structure through despotic aggressiveness over subcontinental scales. These substantial shifts in occurrence rates and abundances of small-bodied species flow on to alter species abundance distributions of entire assemblages over much of eastern Australia.