Delays in DUI blood testing: Impact on cannabis DUI assessments

Objective: This study examined the time from law enforcement dispatch to the first blood draw in cases of driving under the influence (DUI) vehicular homicide and a subset of DUI vehicular assault cases in Colorado in 2012. Laboratory toxicology results were also examined to understand the implications of delays in blood draws in cases of driving while under the influence of marijuana's delta-9-tetrahydrocannabinol (THC).

Methods: Colorado court records were reviewed and information regarding charges, presence of alcohol and/or drugs, time of law enforcement contact and blood draw, crash location, and other contextual factors were identified. The distributions of first blood draw times were studied by charge and by responding law enforcement agency. Toxicology data from a different cohort of DUI traffic arrests in Colorado and Washington were examined to determine the proportion of blood tests for THC that were above specified legal limits in those states.

Results: The average time from law enforcement dispatch to blood draw in cases of vehicular homicide and vehicular assault was 2.32 h (SD ± 1.31 h), with a range of 0.83 to 8.0 h and a median of 2.0 h. Data from DUI traffic arrests found that between 42 and 70% of all cannabinoid-positive traffic arrests tested below 5 ng/ml THC in blood, which is the legal limit in Colorado and Washington.

Conclusion: Given the current delays to blood testing in cases of arrests for vehicular homicide and vehicular assault in Colorado, many blood tests are unlikely to confirm that drivers who are impaired from smoking marijuana have THC levels above established legal limits.     

Can timber and water resources be sustainably co-developed in south-eastern New South Wales, Australia?

In the south-east of New South Wales, Australia, forested catchments are largely relied upon to provide high-quality surface water at low cost to small regional communities. The forests in question are used for multiple purposes including timber production, which can result in conflicts and debate regarding the sustainability of timber and water resources being co-developed. A case study is examined where a logging operation will occur on 3.5% of the Myrtle Creek catchment that is used to supply water to the small township of Wyndham. Modelling based on the water yield response of eucalypt forests to disturbance predicts that during the first four years post-harvest, total streamflows will be increased under the ‘2010 logging’ scenario, with a maximum increase of 2.6% within the first two years. Streamflows will then likely decrease compared to the ‘no logging’ scenario and will continue to do so until regrowth reaches 28 years of age with a maximum 1.4% decrease predicted. Streamflows under both scenarios will continue to increase over time as water yield has been suppressed by forest regeneration following extensive wildfires and logging that occurred from the 1960s to 1980s. It is concluded that timber harvesting, if limited spatially and temporally, can occur without compromising catchment values and may contribute to improved forest heterogeneity and resilience. However, in the face of a changing climate and an increased likelihood of catastrophic high intensity wildfires, the future sustainability of undercapitalised small town water supplies reliant on a single water source is questionable.     

Weekend–weekday aerosols and geographic variability in cloud-to-ground lightning for the urban region of Atlanta, Georgia, USA

We characterized the differences in warm-season weekday and weekend aerosol conditions and cloud-to-ground (CG) flashes (1995–2008) for an 80,000 square kilometer region around Atlanta, Georgia, a city of 5.5 million in the humid subtropics of the southeastern United States. An integration of distance-based multivariate techniques (hierarchical agglomerative clustering, multiresponse permutation procedures, fuzzy kappa statistics, and Mantel tests) indicated a greater concentration of CG flash activity within a 100 km radius around Atlanta under weekday aerosol concentrations. On weekends, these effects contracted toward the city. This minimized any weekly anthropogenic cycle over the more densely populated urban center even though this location had a higher flash density, a higher percentage of days with flashes, and stronger peak currents over the course of a week compared to the surrounding region. The sharper contrasts in weekday and weekend lightning regime developed outside the perimeter of the city over nonurban land uses. Here, lightning on weekend and weekdays differed more in its density, frequency, polarity, and peak current. Across the full extent of the study region, weekday peak currents were stronger and flash days more frequent, suggesting that weekly CG lightning signals have a regional component not tied to a single city source. We integrate these findings in a conceptual model that illustrates the dependency of weekly anthropogenic weather signals on spatial and temporal extent.     

Field measurement of lead in workplace air and paint chip samples by ultrasonic extraction and portable anodic stripping voltammetry

On-site measurement of lead in workplace air filter samples and paint chip samples by ultrasonic extraction and anodic stripping voltammetry (UE-ASV) was evaluated in the field during renovation and remodeling activities in residences having leaded paint. Aerosol and paint samples were collected using standard techniques, and the samples were analyzed on-site for lead content by portable UE-ASV. Lead in sample extracts was subsequently determined by atomic absorption (AA) spectrometry in a fixed-site laboratory. The remaining sample extracts plus undissolved material (air filters or paint particles) were then subjected to hot plate digestion in concentrated nitric acid-30% hydrogen peroxide prior to AA analysis for lead. Field UE-ASV lead data were thereby compared to UE-AA and hot plate digestion-AA results from fixed-site laboratory lead measurement. Determination of lead in air filter samples by UE-ASV (over the range of 5 microg to approximately 800 microg Pb per sample) was extremely well correlated with lead measurement by UE-AA and hot plate digestion-AA procedures. However, a significant negative bias associated with ASV measurement was observed, and this was attributed to a matrix effect. Lead measurement in paint chip samples by UE-ASV (over the range of approximately 10 to approximately 550 microg Pb g(-1)) was well correlated with lead measurement by UE-AA and hot plate digestion-AA procedures. However, correlation and precision were lower for lead measurement in paint samples as compared to aerosol samples, and a negative bias was also observed. Lead measurements by UE-AA were compared to lead determinations by hot plate digestion-AA; these data were highly correlated and demonstrated no significant bias. Thus it was concluded that the ultrasonic extraction procedure performed equivalently to hot plate digestion. It was reasoned that matrix effects due to the preparation and analysis of paint chip particles resulted in greater imprecision as well as negative bias by ASV measurement. Despite significant negative bias in this sample set, UE-ASV offers promise for on-site measurement of lead in samples of interest in occupational and environmental health.     

Comparison of three sampling and analytical methods for the determination of airborne hexavalent chromium

A field study was conducted with the goal of comparing the performance of three recently developed or modified sampling and analytical methods for the determination of airborne hexavalent chromium (Cr(VI)). The study was carried out in a hard chrome electroplating facility and in a jet engine manufacturing facility where airborne Cr(VI) was expected to be present. The analytical methods evaluated included two laboratory-based procedures (OSHA Method ID-215 and NIOSH Method 7605) and a field-portable method (NIOSH Method 7703). These three methods employ an identical sampling methodology: collection of Cr(VI)-containing aerosol on a polyvinyl chloride (PVC) filter housed in a sampling cassette, which is connected to a personal sampling pump calibrated at an appropriate flow rate. The basis of the analytical methods for all three methods involves extraction of the PVC filter in alkaline buffer solution, chemical isolation of the Cr(VI) ion, complexation of the Cr(VI) ion with 1,5-diphenylcarbazide, and spectrometric measurement of the violet chromium diphenylcarbazone complex at 540 nm. However, there are notable specific differences within the sample preparation procedures used in three methods. To assess the comparability of the three measurement protocols, a total of 20 side-by-side air samples were collected, equally divided between a chromic acid electroplating operation and a spray paint operation where water soluble forms of Cr(VI) were used. A range of Cr(VI) concentrations from 0.6 to 960 microg m(-3), with Cr(VI) mass loadings ranging from 0.4 to 32 microg, was measured at the two operations. The equivalence of the means of the log-transformed Cr(VI) concentrations obtained from the different analytical methods was compared. Based on analysis of variance (ANOVA) results, no statistically significant differences were observed between mean values measured using each of the three methods. Small but statistically significant differences were observed between results obtained from performance evaluation samples for the NIOSH field method and the OSHA laboratory method.     

AN INTEGRATIVE APPROACH TOWARDS UNDERSTANDING ECOLOGICAL RESPONSES TO DAM REMOVAL: THE MANATAWNY CREEK STUDY1

ABSTRACT: Dam removal has been proposed as an effective method of river restoration, but few integrative studies have examined ecological responses to the removal of dams. In 1999, we initiated an interdisciplinary study to determine ecological responses to the removal of a 2 m high dam on lower Manatawny Creek in southeastern Pennsylvania. We used an integrative monitoring program to assess the physical, chemical, and biological responses to dam removal. Following removal in 2000, increased sediment transport has led to major changes in channel form in the former impoundment and downstream reaches. Water quality did not change markedly following removal, probably because of the impoundment's short hydraulic residence time (less than two hours at base flow) and infrequent temperature stratification. When the impoundment was converted to a free flowing reach, the composition of the benthic macroinvertebrate and fish assemblages in this portion of Manatawny Creek shifted dramatically from lentic to lotic taxa. Some fish species inhabiting the free flowing reach downstream from the dam were negatively affected by large scale sediment transport and habitat alteration following dam removal, but this appears to be a short term response. Based on our observations and experiences in this study, we provide a list of issues to evaluate when considering future dam removals.     

Characterization and enzymatic degradation of a cross-linked bacterial polyester

The bacterial polyester, poly(-hydroxybutyrate-co--hydroxyvalerate) (PHB/V), was cross-linked with 1, 5, 7, 10, 20, and 30 wt% benzoyl peroxide by thermal decomposition reactions. Solvent extractions were carried out to determine the cross-linked fractions of the films. The sol/gel data were used to estimate cross-link densities. Films of PHB/V cross-linked with 10% benzoyl peroxide were placed in contact with purified depolymerase A secreted byP. lemoignei. These samples exhibited weight loss rates which were half that of un-cross-linked PHB/V, but the network was degraded completely by the enzyme. The results of this study suggest that anendo-type enzymatic degradation may occur, in addition to theexo-type activity, which is normally presumed to occur with theP. lemoignei depolymerase system.     

Mixed-species shoaling in fish: the sensory mechanisms and costs of shoal choice

The mechanisms and functions of mixed-species shoaling were investigated in two sympatric species of cyprinids, the chub and the European minnow, from the river Wharfe where they comprised approximately 70% of all year 0+ fish over a 20-year survey. Chub preferred conspecific shoals over heterospecific ones with olfactory cues being more important than visual ones for shoal choice. This preference was consistent with measurements of length:flank area ratios and length:weight ratios which suggest that both species are similar in appearance. When presented with mixed-species shoals, chub increased the percentage time spent with stimulus shoals with increasing proportions of conspecifics. Feeding experiments suggest that the preference for conspecific shoals is driven by interspecific competition (with minnows out-competing similar-sized chub) and the oddity effect. The importance of this work in the context of species assortment in free-ranging shoals is discussed.