Soil heavy metal content on the hillslope region of Rio de Janeiro,Brazil: reference values

The increasing concern regarding the preservation of soil quality suggests the adoption of quality reference values as a first step in environmental monitoring actions. In this context, the objective of this study was to establish soil quality reference values for Al, Zn, Mn, Cd, Fe, Pb, Ni, Cr, and Cu and to correlate several soil properties with the occurrence of these elements in the hillslope region of Rio de Janeiro State. Sixty-two samples were collected at depths of 0–20 and 20–40 cm and analyzed using the USEPA method 3051A. After clustering analysis, the samples were separated into three groups. Classification functions were obtained based on the variables pH - Mg - Fe - Mn, i.e., the variables that were best related to heavy metal content. We determined to establish the quality reference values for the 75th percentile of the three groups. The relief forms of the area, which facilitate the transport of soil fine-particle fractions and accumulation in lowlands, were revealed to be one of most important factors in understanding the distribution of soil heavy metals.     

Using design effects from previous cluster surveys to guide sample size calculation in emergency settings

A good estimate of the design effect is critical for calculating the most efficient sample size for cluster surveys. We reviewed the design effects for seven nutrition and health outcomes from nine population-based cluster surveys conducted in emergency settings. Most of the design effects for outcomes in children, and one-half of the design effects for crude mortality, were below two. A reassessment of mortality data from Kosovo and Badghis, Afghanistan revealed that, given the same number of clusters, changing sample size had a relatively small impact on the precision of the estimate of mortality. We concluded that, in most surveys, assuming a design effect of 1.5 for acute malnutrition in children and two or less for crude mortality would produce a more efficient sample size. In addition, enhancing the sample size in cluster surveys without increasing the number of clusters may not result in substantial improvements in precision.     

International guidelines on mercury management in small-scale gold mining

This article reports on a stakeholder engagement process to develop the International Guidelines on Mercury Management in Small-Scale Gold Mining. Commissioned by the United Nations Global Mercury Project, the purpose of the guidelines is to assist policymakers, practitioners, researchers, miners and the public in developing strategies for reducing mercury use, eliminating major pollution point sources and reducing risks. The guidelines are proposed with the view of supporting miners and their communities by promoting safer, more efficient practices that improve environmental and human health. The paper discusses challenges in addressing mercury issues and technical measures in the guidelines. The paper also highlights the need for interactive engagement in communities to discuss and adapt the guidelines as appropriate, in order to create technology transfer strategies, regulatory measures and strategic priorities that are suitable to the local context.     

Assessment of a simple function to evaluate the relationship between mass flux reduction and mass removal for organic-liquid contaminated source zones

The efficacy of a simple mass-removal function for characterizing mass-flux-reduction/mass-removal behavior for organic-liquid contaminated source zones was evaluated using the data obtained from a series of flow-cell experiments. The standard function, which employs a constant exponent, could not adequately reproduce the non-singular (multi-step) behavior exhibited by the measured data. Allowing the exponent to change as a function of mass removal (as the organic-liquid distribution and relative permeability change) produced non-singular relationships similar to those exhibited by the measured data. Four methods were developed to dynamically inform the exponent through use of measurable system-indicator parameters. Key factors that mediate the magnitude of mass flux (dilution and source accessibility) were accounted for using measures of source zone cross-sectional area, ganglia-to-pool (GTP) ratio, and relative permeability. The two methods that incorporated only the ganglia-to-pool ratio produced adequate simulations of the observed behavior for early stages of mass removal, but not for later stages. The method that incorporated parameters accounting for the source zone cross-sectional area (i.e., measure of system dilution) and source accessibility (GTP ratio and relative permeability) provided the most representative simulations of the observed data.     

Pictorial intervention in a pediatric hospital environment: Effects on parental affective perception of the unit

In recent decades, research on health care design and planning has highlighted the strong relationship between environmental characteristics and human health. According to a patient-centered model, the focus on the hospital environment is important in reducing the negative effects of hospitalization on the patient, especially in the case of children.     

Abiotic transformation of DDT in aqueous solutions

Significant concentrations of chlorinated pesticides such as 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) and its two main transformation products, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) are still present in soil and sediment systems more than 30 years after DDT use was banned in the United States. DDT enters waterways via the runoff from industrial point sources, agricultural lands and atmospheric deposition. We evaluated zero-valent iron (Fe(0)), ferrous sulfide (FeS), as well as combining them with hydrogen peroxide (H(2)O(2)) as viable treatment technologies for degrading DDT in an aqueous solution. Treatment of DDT with Fe(0) and FeS resulted in approximately 88% and 56% transformation of DDT within 150h, respectively. DDE production was insignificant in all systems. The DDT removal was slower with FeS than with Fe(0), but the amounts of DDD and DDE produced did not exceed baseline. Treatment with a 1:1 mixture of Fe(0)-FeS removed about 95% of the added mass of DDT within 4days and generated significant amounts of DDD and minor amounts of DDMU. When small amounts of H(2)O(2) were introduced halfway through the Fe(0) and FeS treatment times, the mass of DDT decreased by 87% and 96%, respectively, within 2days. Our results demonstrate that mixtures of Fe(0)-FeS in combination with H(2)O(2) can be used for rapid and efficient removal of DDT from aqueous solutions.     

Options for National Parks and Reserves for Adapting to Climate Change

Past and present climate has shaped the valued ecosystems currently protected in parks and reserves, but future climate change will redefine these conditions. Continued conservation as climate changes will require thinking differently about resource management than we have in the past; we present some logical steps and tools for doing so. Three critical tenets underpin future management plans and activities: (1) climate patterns of the past will not be the climate patterns of the future; (2) climate defines the environment and influences future trajectories of the distributions of species and their habitats; (3) specific management actions may help increase the resilience of some natural resources, but fundamental changes in species and their environment may be inevitable. Science-based management will be necessary because past experience may not serve as a guide for novel future conditions. Identifying resources and processes at risk, defining thresholds and reference conditions, and establishing monitoring and assessment programs are among the types of scientific practices needed to support a broadened portfolio of management activities. In addition to the control and hedging management strategies commonly in use today, we recommend adaptive management wherever possible. Adaptive management increases our ability to address the multiple scales at which species and processes function, and increases the speed of knowledge transfer among scientists and managers. Scenario planning provides a broad forward-thinking framework from which the most appropriate management tools can be chosen. The scope of climate change effects will require a shared vision among regional partners. Preparing for and adapting to climate change is as much a cultural and intellectual challenge as an ecological challenge.