Plants as biomarkers for monitoring heavy metal contaminants on landfill sites using sequential extraction and inductively coupled plasma atomic emission spectrophotometry (ICP-AES)

There have been a number of studies investigating metal uptake in plants on contaminated landfill sites, but little on their role as biomarkers to identify metal mobility for continuous monitoring purposes. Vegetation can be used as a biomonitor of site pollution, by identifying the mobilisation of heavy metals and by providing an understanding of their bioavailability. Plants selected were the common nettle (Uritica Dioica), bramble (Rubus Fruticosa) and sycamore (Acer Pseudoplatanus). A study of the soil fractionation was made to investigate the soil properties that are likely to influence metal mobility and a correlation exercise was undertaken to investigate if variations in concentration of metals in vegetation can reflect variations in concentration of the metals in soil. The soil was digested using aqua regia in a microwave closed vessel. The vegetation was digested using both microwave and a hydrogen peroxide-nitric acid mixture, refluxed on a heating block and a comparison made. The certified reference materials (CRMs) used were Standard Reference Material (SRM) 1547, peach leaves for vegetation (NIST) and for soil CRM 143R, sewage sludge-amended soil (BCR). The relative standard deviations (RSDs) were 2-6% for the analyses. Our findings show evidence of phytoextraction by some plants, (especially bramble and nettle), with certain plants, (sycamore) exhibiting signs of phytostabilisation. The evidence suggests that there is a degree of selectivity in metal uptake and partitioning within the plant compartments. It was also possible to correlate mobility phases of certain metals (Pb, Cu and Zn) using the soil and plant record. Zn and Cu exhibited the greatest potential to migrate from the roots to the leaves, with Pb found principally in the roots of ground vegetation. Our results suggest that analysis of bramble leaves, nettle leaves and roots can be used to monitor the mobility of Pb in the soil with nettle, bramble and sycamore leaves to monitor Cu and Zn.     

Frequency and determinants of recommended workplace violence prevention measures

PROBLEM: Limited information exists concerning adoption of workplace violence prevention measures by employers and the factors influencing their adoption. METHODS: A weighted sample of North Carolina workplaces (n=210) in operation January 1994 through March 1998 was used to estimate prevalence of 18 measures and identify community and workplace predictors of having >/=5 recommended measures. RESULTS: Location in a metropolitan area most strongly predicted presence of >/=5 administrative safety measures while a history of workplace violence and being in a high crime area were negatively associated. Belonging to an industry considered to be high-risk for workplace homicide was most strongly associated with having >/=5 environmental safety measures. DISCUSSION: Factors influencing high prevalence of violence prevention measures were related to business type, violence history, and location. Knowledge of factors influencing adoption of recommended workplace violence prevention measures can help tailor interventions to diverse industry settings. IMPACT ON INDUSTRY: An important contribution to the understanding and mitigation of workplace homicide is knowledge of the extent of implementation of recommended workplace violence prevention guidelines and factors influencing their adoption. Identifying factors that influence the prevalence and adoption of workplace violence safety interventions can help to tailor development of interventions to address the issue of workplace homicide across diverse industry settings.     

Gauging the societal impacts of natural disasters using a capability approach

There is a widely acknowledged need for a single composite index that provides a comprehensive picture of the societal impact of disasters. A composite index combines and logically organizes important information policy‐makers need to allocate resources for the recovery from natural disasters; it can also inform hazard mitigation strategies. This paper develops a Disaster Impact Index (DII) to gauge the societal impact of disasters on the basis of the changes in individuals’ capabilities. The DII can be interpreted as the disaster impact per capita. Capabilities are dimensions of individual well‐being and refer to the genuine opportunities individuals have to achieve valuable states and activities (such as being adequately nourished or being mobile). After discussing the steps required to construct the DII, this article computes and compares the DIIs for two earthquakes of similar magnitude in two societies at different levels of development and of two disasters (earthquake and wind storm) in the same society.     

Partitioning vegetation response to anthropogenic stress to develop multi-taxa wetland indicators.

Emergent plants can be suitable indicators of anthropogenic stress in coastal wetlands if their responses to natural environmental variation can be parsed from their responses to human activities in and around wetlands. We used hierarchical partitioning to evaluate the independent influence of geomorphology, geography, and anthropogenic stress on common wetland plants of the U.S. Great Lakes coast and developed multi-taxa models indicating wetland condition. A seven-taxon model predicted condition relative to watershed-derived anthropogenic stress, and a four-taxon model predicted condition relative to within-wetland anthropogenic stressors that modified hydrology. The Great Lake on which the wetlands occurred explained an average of about half the variation in species cover, and subdividing the data by lake allowed us to remove that source of variation. We developed lake-specific multi-taxa models for all of the Great Lakes except Lake Ontario, which had no plant species with significant independent effects of anthropogenic stress. Plant responses were both positive (increasing cover with stress) and negative (decreasing cover with stress), and plant taxa incorporated into the lake-specific models differed by Great Lake. The resulting models require information on only a few taxa, rather than all plant species within a wetland, making them easier to implement than existing indicators.     

OHP02 gravity wave campaign in relation to optical turbulence

Herein we present a campaign dedicated to the detection and the characterization of Gravity Waves (GW) in the Earth’s atmosphere in relation to the generation of Optical Turbulence (OT). The observations took place in France from 17 to 24 July 2002 at the Haute Provence Observatory (OHP) and simultaneously at the Sirene Observatory, some 20 km apart. From both sites, several balloons were launched that measured the classical PTU-Wind profiles and additionally the structure constant of the temperature field vertical profiles. A Generalized Scidar (GS) technique was implemented at the 1.93 m-diameter OHP telescope, providing profiles every minute. From our observations, a significant amount of GW activity was observed at both sites, but without clear evidence of correlation between the two sites. It seems from our observations that a wide spectrum of GW is present at a given altitude and that this could result in a lack of correlation between observations made from two sites 20 km apart. Most GW are non-stationary with long horizontal wavelengths (λ ∼ 100–200 km), kilometric vertical wavelengths (λ ~ 0.5–2 km) and long intrinsic period (T ~ 2–15 h). They belong in the category of “hydrostatic rotating or non-rotating waves”. Layers of optical turbulence detected by balloons and the Scidar technique correlate well with regions of GW activity. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Towards resolving the phosphorus chaos created by food systems

Ambio - The chaotic distribution and dispersal of phosphorus (P) used in food systems (defined here as disorderly disruptions to the P cycle) is harming our environment beyond acceptable limits. An...     

Separation of brown carbon from black carbon for IMPROVE and Chemical Speciation Network PM2.5 samples

The replacement of the Desert Research Institute (DRI) model 2001 with model 2015 thermal/optical analyzers (TOAs) results in continuity of the long-term organic carbon (OC) and elemental carbon (EC) database, and it adds optical information with no additional carbon analysis effort. The value of multiwavelength light attenuation is that light absorption due to black carbon (BC) can be separated from that of brown carbon (BrC), with subsequent attribution to known sources such as biomass burning and secondary organic aerosols. There is evidence of filter loading effects for the 25% of all samples with the highest EC concentrations based on the ratio of light attenuation to EC. Loading corrections similar to those used for the seven-wavelength aethalometer need to be investigated. On average, nonurban Interagency Monitoring of PROtected Visual Environments (IMPROVE) samples show higher BrC fractions of short-wavelength absorption than urban Chemical Speciation Network (CSN) samples, owing to greater influence from biomass burning and aged aerosols, as well as to higher primary BC contributions from engine exhaust at urban sites. Sequential samples taken during an Everglades National Park wildfire demonstrate the evolution from flaming to smoldering combustion, with the BrC fraction increasing as smoldering begins to dominate the fire event.

Implications: The inclusion of seven wavelengths in thermal/optical carbon analysis of speciated PM_2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm) samples allows contributions from biomass burning and secondary organic aerosols to be estimated. This separation is useful for evaluating control strategy effectiveness, identifying exceptional events, and determining natural visibility conditions.     

Policy Utopias for Nutrient Credit Trading Programs with Nonpoint Sources

A promising program to address water contamination from nutrients is water quality trading (WQT), whereby entities with high abatement costs purchase credits from entities with lower abatement costs. The concept has found some success with point source water pollution, but very few trades have occurred in over 50 programs in the United States (U.S.) that have focused on nonpoint sources (NPSs). To understand why success has been slow, we identified three environments needed for programs to succeed: physical, economic, and institutional. We estimate that only 5% of watersheds in the U.S. currently listed as nutrient impaired provide a viable physical environment for trading nitrogen; 13% are suitable for phosphorus. Economic and institutional challenges would shrink that domain even further. Therefore, we find places with the ideal physical, economic, and institutional environments necessary for feasible WQT programs are virtual policy utopias — rare places with ideal environments. Fortunately, a growing literature provides the tools necessary to identify where these policy utopias are and to expand that domain through a better understanding about how to manage WQT programs more effectively.     

Evaluating portable infrared spectrometers for measuring the silica content of coal dust

Miners face a variety of respiratory hazards while on the job, including exposure to silica dust which can lead to silicosis, a potentially fatal lung disease. Currently, field-collected filter samples of silica are sent for laboratory analysis and the results take weeks to be reported. Since the mining workplace is constantly moving into new and often different geological strata with changing silica levels, more timely data on silica levels in mining workplaces could help reduce exposures. Improvements in infrared (IR) spectroscopy open the prospect for end-of-shift silica measurements at mine sites. Two field-portable IR spectrometers were evaluated for their ability to quantify the mass of silica on filter samples loaded with known amounts of either silica or silica-bearing coal dust (silica content ranging from 10-200 μg/filter). Analyses included a scheme to correct for the presence of kaolin, which is a confounder for IR analysis of silica. IR measurements of the samples were compared to parallel measurements derived using the laboratory-based U.S. Mine Safety and Health Administration P7 analytical method. Linear correlations between Fourier transform infrared (FTIR) and P7 data yielded slopes in the range of 0.90-0.97 with minimal bias. Data from a variable filter array spectrometer did not correlate as well, mainly due to poor wavelength resolution compared to the FTIR instrument. This work has shown that FTIR spectrometry has the potential to reasonably estimate the silica exposure of miners if employed in an end-of-shift method.