Comparative study of non-invasive methods for assessing Daphnia magna embryo toxicity

Embryos, unlike adults, are typically sessile, which allows for an increase in the available metrics that can be used to assess chemical toxicity. We investigate Daphnia magna development rate and oxygen consumption as toxicity metrics and compare them to arrested embryo development using four different techniques with potassium cyanide (KCN) as a common toxicant. The EC₅₀ (95 % CI) for arrested development was 2,535 (1,747–3,677) μg/L KCN. Using pixel intensity changes, recorded with difference imaging, we semi-quantitatively assessed a decrease in development rate at 200 μg/L KCN, threefold lower than the arrested development lowest observed effect concentration (LOEC). Respirometry and self-referencing (SR) microsensors were two unique techniques used to assess oxygen consumption. Using respirometry, an increase in oxygen consumption was found in the 5 μg/L KCN treatment and a decrease for 148 μg/L, but no change was found for the 78 μg/L KCN treatment. Whereas, with SR microsensors, we were able to detect significant changes in oxygen consumption for all three treatments: 5, 78, and 148 μg/L KCN. While SR offered the highest sensitivity, the respirometry platform developed for this study was much easier to use to measure the same endpoint. Oxygen consumption may be subject to change during the development process, meaning consumption assessment techniques may only be useful only for short-term experiments. Development rate was a more sensitive endpoint though was only reliable four of the six embryonic developmental stages examined. Despite being the least sensitive endpoint, arrested embryo development was the only technique capable of assessing the embryos throughout all developmental stages. In conclusion, each metric has advantages and limitations, but because all are non-invasive, it is possible to use any combination of the three.     

Interlaboratory and Intralaboratory Variability in the Analysis of Mercury in Coal

Abstract

With the passage of the 1990 Clean Air Act Amendments (CAAA), accurate determination of the concentration of mercury in coal has become an increasingly important issue. To address this issue, CONSOL R&D conducted a round robin analytical program to determine the interlaboratory and intralaboratory variability in the measurement of mercury in coal. CONSOL supplied homogeneous splits of Pittsburgh and Illinois #6 seam coals, and the NIST 1632b coal standard to eleven laboratories, twice each, over a one-year period. A twelfth laboratory analyzed the coals once. A European coal standard, certified for mercury, was analyzed at the completion of the round robin study to evaluate accuracy. The round robin participants included representatives from industry, government, and academia. The laboratories, which are experienced in mercury-in-coal analysis, used various state-of-the-art sample preparation and analysis procedures in the study. The round robin results indicate that a substantial level of variability exists in the mercury-in-coal determination. Earlier studies1 found similar results. The relative intralaboratory repeatability was 0.02 ppm and the relative interlaboratory reproducibility ranged from 0.04 to 0.05 ppm. The study showed that laboratory variability can be greatly skewed by outlier values. Fifty-six percent of the results for the European coal standard fell within a 95% confidence interval of the standard (0.138 ± 0.11 ppm). These results indicate that accuracy is not method-dependent.     

Characterization of particulate matter and gaseous emissions of a C-130H aircraft

The gaseous and nonvolatile particulate matter (PM) emissions of two T56-A-15 turboprop engines of a C-130H aircraft stationed at the 123rd Airlift Wing in the Kentucky Air National Guard were characterized. The emissions campaign supports the Strategic Environmental Research and Development Program (SERDP) project WP-1401 to determine emissions factors from military aircraft. The purpose of the project is to develop a comprehensive emissions measurement program using both conventional and advanced techniques to determine emissions factors of pollutants, and to investigate the spatial and temporal evolutions of the exhaust plumes from fixed and rotating wing military aircraft. Standard practices for the measurement of gaseous emissions from aircraft have been well established; however, there is no certified methodology for the measurement of aircraft PM emissions. In this study, several conventional instruments were used to physically characterize and quantify the PM emissions from the two turboprop engines. Emissions samples were extracted from the engine exit plane and transported to the analytical instrumentation via heated lines. Multiple sampling probes were used to assess the spatial variation and obtain a representative average of the engine emissions. Particle concentrations, size distributions, and mass emissions were measured using commercially available aerosol instruments. Engine smoke numbers were determined using established Society of Automotive Engineers (SAE) practices, and gaseous species were quantified via a Fourier-transform infrared-based gas analyzer. The engines were tested at five power settings, from idle to take-off power, to cover a wide range of operating conditions. Average corrected particle numbers (PNs) of (6.4-14.3) x 10(7) particles per cm3 and PN emission indices (EI) from 3.5 x 10(15) to 10.0 x 10(15) particles per kg-fuel were observed. The highest PN EI were observed for the idle power conditions. The mean particle diameter varied between 50 nm at idle to 70 nm at maximum engine power. PM mass EI ranged from 1.6 to 3.5 g/kg-fuel for the conditions tested, which are in agreement with previous T56 engine measurements using other techniques. Additional PM data, smoke numbers, and gaseous emissions will be presented and discussed.     

XANES spectroscopic analysis of phosphorus speciation in alum-amended poultry litter

Aluminum sulfate (alum; Al(2)(SO(4))(3).14H(2)O) is used as a chemical treatment of poultry litter to reduce the solubility and release of phosphate, thereby minimizing the impacts on adjacent aquatic ecosystems when poultry litter is land applied as a crop fertilizer. The objective of this study was to determine, through the use of X-ray absorption near edge structure (XANES) spectroscopy and sequential extraction, how alum amendments alter P distribution and solid-state speciation within the poultry litter system. Our results indicate that traditional sequential fractionation procedures may not account for variability in P speciation in heterogeneous animal manures. Analysis shows that NaOH-extracted P in alum amended litters is predominantly organic ( approximately 80%), whereas in the control samples, >60% of NaOH-extracted P was inorganic P. Linear least squares fitting (LLSF) analysis of spectra collected of sequentially extracted litters showed that the P is present in inorganic (P sorbed on Al oxides, calcium phosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum-amended poultry litter. When determining land application rates of poultry litter, all of these compounds must be considered, especially organic P. Results of the sequential extractions in conjunction with LLSF suggest that no P species is completely removed by a single extractant. Rather, there is a continuum of removal as extractant strength increases. Overall, alum-amended litters exhibited higher proportions of Al-bound P species and phytic acid, whereas untreated samples contained Ca-P minerals and organic P compounds. This study provides in situ information about P speciation in the poultry litter solid and about P availability in alum- and non-alum-treated poultry litter that will dictate P losses to ground and surface water systems.     

Optimal Policies for Aggregate Recycling from Decommissioned Forest Roads

To mitigate the adverse environmental impact of forest roads, especially degradation of endangered salmonid habitat, many public and private land managers in the western United States are actively decommissioning roads where practical and affordable. Road decommissioning is associated with reduced long-term environmental impact. When decommissioning a road, it may be possible to recover some aggregate (crushed rock) from the road surface. Aggregate is used on many low volume forest roads to reduce wheel stresses transferred to the subgrade, reduce erosion, reduce maintenance costs, and improve driver comfort. Previous studies have demonstrated the potential for aggregate to be recovered and used elsewhere on the road network, at a reduced cost compared to purchasing aggregate from a quarry. This article investigates the potential for aggregate recycling to provide an economic incentive to decommission additional roads by reducing transport distance and aggregate procurement costs for other actively used roads. Decommissioning additional roads may, in turn, result in improved aquatic habitat. We present real-world examples of aggregate recycling and discuss the advantages of doing so. Further, we present mixed integer formulations to determine optimal levels of aggregate recycling under economic and environmental objectives. Tested on an example road network, incorporation of aggregate recycling demonstrates substantial cost-savings relative to a baseline scenario without recycling, increasing the likelihood of road decommissioning and reduced habitat degradation. We find that aggregate recycling can result in up to 24% in cost savings (economic objective) and up to 890% in additional length of roads decommissioned (environmental objective).     

Reconciliation of development and ecosystems: the ecology of governance in the International Columbia River Basin

Regional Environmental Change - This article explores the emergence of formal and informal bridging organizations to facilitate solutions to water conflict at the scale of the water resource. This...     

Estimating population abundance using counts from an auxiliary population

Environmental and Ecological Statistics - We develop a new method for estimating population abundance for notoriously difficult to count populations. This is made possible using an easy to count...     

Factors contributing to serious and fatal injuries in belted rear seat occupants in frontal crashes

Abstract

Objectives: Earlier research has shown that the rear row is safer for occupants in crashes than the front row, but there is evidence that improvements in front seat occupant protection in more recent vehicle model years have reduced the safety advantage of the rear seat versus the front seat. The study objective was to identify factors that contribute to serious and fatal injuries in belted rear seat occupants in frontal crashes in newer model year vehicles.

Methods: A case series review of belted rear seat occupants who were seriously injured or killed in frontal crashes was conducted. Occupants in frontal crashes were eligible for inclusion if they were 6 years old or older and belted in the rear of a 2000 or newer model year passenger vehicle within 10 model years of the crash year. Crashes were identified using the 2004–2015 National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and included all eligible occupants with at least one Abbreviated Injury Scale (AIS) 3 or greater injury. Using these same inclusion criteria but split into younger (6 to 12 years) and older (55+ years) cohorts, fatal crashes were identified in the 2014–2015 Fatality Analysis Reporting System (FARS) and then local police jurisdictions were contacted for complete crash records.

Results: Detailed case series review was completed for 117 rear seat occupants: 36 with Maximum Abbreviated Injury Scale (MAIS) 3+ injuries in NASS-CDS and 81 fatalities identified in FARS. More than half of the injured and killed rear occupants were more severely injured than front seat occupants in the same crash. Serious chest injury, primarily caused by seat belt loading, was present in 22 of the injured occupants and 17 of the 37 fatalities with documented injuries. Nine injured occupants and 18 fatalities sustained serious head injury, primarily from contact with the vehicle interior or severe intrusion. For fatal cases, 12 crashes were considered unsurvivable due to a complete loss of occupant space. For cases considered survivable, intrusion was not a large contributor to fatality.

Discussion: Rear seat occupants sustained serious and fatal injuries due to belt loading in crashes in which front seat occupants survived, suggesting a discrepancy in restraint performance between the front and rear rows. Restraint strategies that reduce loading to the chest should be considered, but there may be potential tradeoffs with increased head excursion, particularly in the absence of rear seat airbags. Any new restraint designs should consider the unique needs of the rear seat environment.     

Reach and messages of the world's largest ivory burn

Recent increases in ivory poaching have depressed African elephant populations. Successful enforcement has led to ivory stockpiling. Stockpile destruction is becoming increasingly popular, and most destruction has occurred in the last 5 years. Ivory destruction is intended to send a strong message against ivory consumption, both in promoting a taboo on ivory use and catalyzing policy change. However, there has been no effort to establish the distribution and extent of media reporting on ivory destruction events globally. We analyzed media coverage of the largest ivory destruction event in history (Kenya, 30 April 2016) across 11 nation states connected to ivory trade. We used an online‐media crawling tool to search online media outlets and subjected 5 of the largest print newspapers (by circulation) in 5 nations of interest to content analysis. Most online news on the ivory burn came from the United States (81% of 1944 articles), whereas most of the print news articles came from Kenya (61% of 157 articles). Eighty‐six to 97% of all online articles reported the burn as a positive conservation action, whereas 4–50% discussed ivory burning as having a negative impact on elephant conservation. Most articles discussed law enforcement and trade bans as effective for elephant conservation. There was more relative search interest globally in the 2016 Kenyan ivory burn than any other burn in 5 years. Ours is the first attempt to track the reach of media coverage relative to an ivory burn and provides a case study in tracking the effects of a conservation‐marketing event.