Energy vs the environment

Optimal development programs that explicitly account for the environment impacts of extracting energy resources are analyzed. Possibilities of storing the resources above ground once it has been extracted are examined When environmental disruption results from resource extraction, as in the case of strip mining or drilling for oil, then the socially optimal rates of resource consumption and extraction depend on the type and severity of the environmental impact and on the prospects of storing the resource above ground.     

Temporal stability of gene frequencies within genetically heterogeneous populations of the queen scallop Aequipecten (Chlamys) opercularis

The widely held assumption that gene frequencies within samples of multi-aged organisms are temporally stable has rarely been tested. In order to test this assumption in the commercially exploited bivalve scallop Aequipecten (Chlamys) opercularis (L.), 12 populations were sampled from around the UK over the period 1988–1990 and each was assayed at four putative polymorphic enzyme loci. Most populations were comprised of 3 to 4 year-classes, distinguishable by annual rings laid down on the shell. Three alleles from each locus were used as discriminant-function variables. Discriminant-function analysis based on allele frequencies averaged for each inividual year-class (45 demes) revealed highly significant inter-site heterogeneity. A posteriori classification of individual year-classes based on the discriminant analysis resulted in assignment of year-classes to the correct home site in 80% of cases. If allozyme neutrality is assumed, the phenomenon of predominant local allele frequency-stability through time within populations which are genetically heterogeneous from one site to another raises the possibility that queen scallop populations may be self-recruiting. Despite a planktonic larval phase lasting up to several weeks, this possibility is not excluded by the available hydrographic data.     

An experimental soft-release of oil-spill rehabilitated American coots (Fulica americana): I. Lingering effects on survival, condition and behavior

In spring 1995, we studied survival, condition and behavior of 37 oiled/rehabilitated (OR) American coots (Fulica americana) (RHB) and compared them to 38 wild-caught, non-oiled and non-rehabilitated coots (REF). All coots were wing-clipped to prevent long-range dispersal, mixed equally and randomly and soft-released into two fenced marshes. Twenty RHB+20 REF coots were subjected to handling and sampling four times during the 4-month study and the remainder were left undisturbed. The study ended before any coots dispersed following remige regrowth. Overall survival was significantly lower for RHB coots, regardless of the way survival was viewed (four Chi 2 tests varied between p<0.045 and p<0.006). Mortality was 2.1 times higher in RHB coots: 51% mortality in RHB coots and 24% in REF coots (4 months total). RHB coots began the experiment 9% lighter in mean body condition indices (BCI=a standardization that corrected for different-sized birds) than REF coots, but REF coots also needed a period of adjustment to captivity. BCIs then varied (p<0.02) similarly among both groups throughout the experiment. Initially, RHB coots lost more weight in comparison to REF coots (although RHB coots fed more), but those RHB coots that did survive recovered to REF-comparable BCIs after about 6 weeks: both higher and equivalent at the beginning of moult and then both equivalent but lower through the moulting period. Long-term RHB coot and REF coot survivors both had significant (p<0.001) positive correlations between their initial and ending body weights. A similar relationship was also suggested for the non-surviving REF coots, but could not be tested for statistical significance. In contrast to all other groups, however, non-surviving RHB coots failed to show any relationship between their initial and ending body weights (p>0.10), indicating that non-surviving RHB coots were unable to gain or maintain body condition for about 2-3 months following their oiling/rehabilitation experience. Throughout the experiment, RHB coots preened more on water and on land, bathed more, slept less during the day, and exhibited feeding and drinking behaviors more frequently or of greater duration than REF coots (all statistical tests with Bonferroni-corrected p<0.05).     

Characterization of emissions of dioxins and furans from ethylene dichloride, vinyl chloride monomer and polyvinyl chloride facilities in the United States. Consolidated report

This is the consolidated report of emissions of PCDD/F from facilities in the organic chemical manufacturing chain leading to polyvinyl chloride. Data have been gathered from facilities in the US and Canada from a number of manufacturers and at various steps in the manufacturing process. Estimates of US emissions or transfers of PCDD/F were generated on an "Upper Bound" and "Most Likely" basis. The Most Likely estimate of US emissions of PCDD/F to the open environment, that is, air, water and land surface by facilities in this chain, based on evaluation of non-detects at one-half the detection limit is about 12 g I-TEQ per year. On this same basis, an estimated 19 g is disposed of in secure landfills.     

Improved recovery of repeat intoxicated drivers using fingernails and blood spots to monitor alcohol and other substance abuse

Objectives: This study reports the results of a pilot program in Kenosha County that used a combination of direct biomarkers extracted from blood spots and nails to monitor repeat intoxicated drivers for their use of alcohol and drugs with a detection window spanning from 3 weeks to several months. The objectives were to test whether the direct biomarkers phosphatidylethanol (PEth), ethylglucuronide (EtG), and 5 drug metabolites would (1) help assessors obtain a more objective evaluation of repeat offenders during the assessment interview, (2) allow for timely identification of relapses and improve classification of drivers into risk categories, and (3) predict recidivism by identifying offenders most likely to obtain a subsequent operating while intoxicated (OWI) offense within 4 years of enrollment in the program.

Methods: All (N = 261) repeat offenders were tested using PEth obtained from blood spots and EtG obtained from fingernails; 159 participants were also tested for a 5 drugs of abuse nail panel. Drivers were tested immediately after the assessment interview (baseline) and at 3, 6, 9, and 12 months after baseline. Based on biomarker results and self-reports of abstinence, offenders were classified into different risk categories and required to follow specific testing timelines based on the program's decision tree.

Results: The baseline analysis shows that 60% of drivers tested positive for alcohol biomarkers (EtG, PEth, or both) at the assessment interview, with lower detection rates (0–11%) for the 5 drug metabolites. The comparison of biomarkers results to self-reports of abstinence identified 28% of all offenders as high risk and assigned them to more frequent testing and more intense monitoring. The longitudinal analysis shows that 56% (completers) of participants completed the program successfully and the remaining 44% (noncompliant) terminated prematurely. Two thirds (68%) of the completers were able to reduce or control their drinking and one third relapsed at least one time during their mandated monitoring periods. After a brief intervention by the assessors, 79% of relapsers tested negative for biomarkers in their repeat tests. The rearrest analysis showed that offenders classified in the noncompliant and relapsers groups were 7 times more likely to receive a new OWI 4 years after enrollment compared to drivers classified as abstainers or controllers. Refractory drivers were monitored the longest and reported no subsequent rearrests.

Conclusion: These findings demonstrate the benefits of more individualized interventions with repeat OWI offenders and calls for further development of multimodal approaches in traffic medicine including those that use direct alcohol biomarkers as evidence-based practices to reduce recidivism.     

Kinetics of biochemically driven metal precipitation in synthetic landfill leachate

This study investigates the effectiveness of using metal sulphide and carbonate precipitation mechanisms combined with a landfill‐derived mixed bacterial population. The study was conducted under controlled substrate conditions in anaerobic batch reactors. High chemical oxygen demand (COD):sulphate ratios, butyrate, propionate, and acetate were used anaerobically by bacteria for growth with associated sulphate reduction as well as sulphide and carbonate generation. Propionate and butyrate degradation occurred during sulphate reduction by sulphate‐reducing bacteria while acetate degradation was associated with methanogenesis by methanogenic bacteria. Using low COD, sulphate ratios showed limited acetate utilization, but sulphate reduction still occurred. Precipitation of Cd, Cu, Zn, Ni, and Fe sulphides occurred quickly and was completed in 15 to 30 days, while Ca, Mn, and Mg carbonates formed after 40 to 50 days and some soluble metal remained even after 120 days. The rate of metal precipitation was in the order of Cd>Cu>Zn>Ni>Fe>Mn>Mg>Ca. Bacterially mediated metal precipitation occurred slower than that recognized for chemical precipitation. These findings suggest that contaminant transport models based on chemical equilibrium metal behaviors may over‐predict metal removal by bio‐precipitation. © 2002 Wiley Periodicals, Inc.     

Emission Control in Coking Operations By Use of Stage Charging

At the Clairton Coke Works of the United States Steel Corporation (the world’s largest coke plant), with coal charges of about 30,000 net tons per day, a system designated as “stage charging” has been developed for charging coal into the coke oven chamber without emissions to the atmosphere. The principles of the system are based on controlled sequential flow of the coal from the charging hoppers, during which the oven chamber is maintained under a very slight negative pressure condition by use of steam aspiration in the offtakes for on-the-main charging. The techniques are basic but require knowledge of the coal characteristics, adequate and properly maintained aspirating systems, including clean offtake piping, control of coal volume in the individual hoppers, and last, and probably most important, adherence by the operating crew to specific charging and leveling practices.