Catalytic activities of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol

We report the catalytic properties of ultra-small β-FeOOH nanorods in ozonation of 4-chlorophenol (4-CP). XRD, TEM, EDS, SAED, FTIR and BET were used to characterize the prepared material. Interaction between O₃ and β-FeOOH was evident from the FTIR spectra. The removal efficiency of 4-CP was significantly enhanced in the presence of β-FeOOH compared to ozone alone. Removal efficiency of 99% and 67% was achieved after 40 min in the presence of combined ozone and catalyst and ozone only, respectively. Increasing catalyst load increased COD removal efficiency. Maximum COD removal of 97% was achieved using a catalyst load of 0.1 g/100 mL of 4-CP solution. Initial 4-CP concentration was not found to be rate limiting below 2 × 10^− 3 mol/L. The catalytic properties of the material during ozonation process were found to be pronounced at lower initial pH of 3.5. Two stage first order kinetics was applied to describe the kinetic behavior of the nanorods at low pH. The first stage of catalytic ozonation was attributed to the heterogeneous surface breakdown of O₃ by β-FeOOH, while the second stage was attributed to homogeneous catalysis initiated by reductive dissolution of β-FeOOH at low pH.     

Effects of introducing energy recovery processes to the municipal solid waste management system in Ulaanbaatar,Mongolia

Currently, most developing countries have not set up municipal solid waste management systems with a view of recovering energy from waste or reducing greenhouse gas emissions. In this article, we have studied the possible effects of introducing three energy recovery processes either as a single or combination approach, refuse derived fuel production, incineration and waste power generation, and methane gas recovery from landfill and power generation in Ulaanbaatar, Mongolia, as a case study. We concluded that incineration process is the most suitable as first introduction of energy recovery. To operate it efficiently, 3Rs strategies need to be promoted. And then, RDF production which is made of waste papers and plastics in high level of sorting may be considered as the second step of energy recovery. However, safety control and marketability of RDF will be required at that moment.     

Tile water quality following liquid swine manure application into standing corn

The quality of water draining fields fertilized with liquid swine (Sus scrofa) manure (LSM) sidedressed into standing corn (Zea mays L.) at rates ranging from 0 to 94 m(3) ha(-1), either topdressed (TD) onto the surface, or injected (INJ) into the soil once annually for each of three consecutive years was evaluated. Liquid swine manure application rate was a critical driver of preferential flow of LSM to tile as detected by turbidity, concentrations of NH(4)(+)-N, dissolved reactive phosphorus (DRP), and the presence of enteric bacteria (Escherichia coli). Contaminant movement to drains occurred immediately after 75 and 94 m(3) LSM ha(-1) were injected (e.g., 2.5 mg DRP L(-1), 3-yr average). With injection of 56 m(3) ha(-1) or less, drainage water was not turbid and concentrations of NH(4)(+)-N, DRP, and enteric bacteria were dramatically lower than with the higher rates, even when tiles flowed freely during manure application. Application method also affected tile water quality. With TD applications (37 and 56 m(3) ha(-1)), nutrients and bacteria did not move to tiles at the time of application, but with rains that fell within 3 d after application, concentrations increased (e.g., 0.1 mg DRP L(-1)), although less than with INJ. Overall, sidedress injection rates that supplied adequate crop nutrients did not compromise drainage water quality.     

A preliminary validation of a new measure of occupational health and safety

INTRODUCTION: This article describes the validation of an instrument designed to conduct an Occupational Health and Safety (OHS) self-diagnosis using workers observations of tangible facts and actions in the workplace. The instrument puts the emphasis on observable factors that make it possible to act proactively before accidents actually occur. METHOD: Three companies were recruited from the printing sector in Québec based on their OHS performance (low, medium, and high), their interest in the project, and their availability. The master sample was composed of 269 people. Partial least squares (PLS) and vanishing tetrad analyses were used to study the behavior of the formative scales developed. RESULTS: The results indicate that partial revision of the instrument will be necessary to reach a fully satisfying level of validity. With regards to the statistical approach adopted, the use of a macro called CTA-SAS 2.0 developed by Bollen and Ting [Bollen, K.A., & Ting, K.-F. (1993). Confirmatory tetrad analysis. In P.V. Marsden (Ed.), Social methodology.Vol.23 (pp.147-176). Cambridge, MA: Blackwell, 23] has proven to be effective in providing a suitable statistical treatment of the latent formative variables on which our instrument's development is based. CONCLUSION: The results suggest that the instrument appears to be relatively robust and appropriate to diagnose OHS leading measures. IMPACT ON INDUSTRY: In the long run, this instrument will make it possible for companies to draw a more refined picture of OHS evolution, even in the absence of occupational injuries.     

Recovery from blast fishing on coral reefs: a tale of two scales.

Dynamite or "blast" fishing is one of the most immediate and destructive threats to coral reefs worldwide. However, little is known about the long-term ecosystem effects of such blasts or the dynamics of recovery. Here, we examine coral reef recovery in the simplest case of acute single blasts of known age, as well as recovery from chronic blasting over greater spatial and temporal scales. Rubble resulting from single blasts slowly stabilized, and craters filled in with surrounding coral and new colonies. After five years, coral cover within craters no longer differed significantly from control plots. In contrast, extensively bombed areas showed no significant recovery over the six years of this study, despite adequate supply of coral larvae. After extensive blasting, the resulting coral rubble shifts in ocean currents, forming unstable "killing fields" for new recruits. While recently tested rehabilitation methods might be feasible on a small scale, human intervention is unlikely to be effective on large spatial scales, highlighting the need for effective management to prevent blast fishing in the first place.     

Nutrient cycling by fish supports relatively more primary production as lake productivity increases

Animals can be important in nutrient cycling in particular ecosystems, but few studies have examined how this importance varies along environmental gradients. In this study we quantified the nutrient cycling role of an abundant detritivorous fish species, the gizzard shad (Dorosoma cepedianum), in reservoir ecosystems along a gradient of ecosystem productivity. Gizzard shad feed mostly on sediment detritus and excrete sediment-derived nutrients into the water column, thereby mediating a cross-habitat translocation of nutrients to phytoplankton. We quantified nitrogen and phosphorus cycling (excretion) rates of gizzard shad, as well as nutrient demand by phytoplankton, in seven lakes over a four-year period (16 lake-years). The lakes span a gradient of watershed land use (the relative amounts of land used for agriculture vs. forest) and productivity. As the watersheds of these lakes became increasingly dominated by agricultural land, primary production rates, lake trophic state indicators (total phosphorus and chlorophyll concentrations), and nutrient flux through gizzard shad populations all increased. Nutrient cycling by gizzard shad supported a substantial proportion of primary production in these ecosystems, and this proportion increased as watershed agriculture (and ecosystem productivity) increased. In the four productive lakes with agricultural watersheds (>78% agricultural land), gizzard shad supported on average 51% of phytoplankton primary production (range 27-67%). In contrast, in the three relatively unproductive lakes in forested or mixed-land-use watersheds (>47% forest, <52% agricultural land), gizzard shad supported 18% of primary production (range 14-23%). Thus, along a gradient of forested to agricultural landscapes, both watershed nutrient inputs and nutrient translocation by gizzard shad increase, but our data indicate that the importance of nutrient translocation by gizzard shad increases more rapidly. Our results therefore support the hypothesis that watersheds and gizzard shad jointly regulate primary production in reservoir ecosystems.     

Development and application of a methodology for determining background groundwater quality at the Savannah River Site

A statistical methodology formulated for defining background or baseline levels of constituents of concern in groundwater is presented. The methodology was developed for the case where prior delineation of unimpacted areas is not possible because of site history and a large set of groundwater monitoring measurements exists. Consideration was given to spatial and temporal trends, outliers, and final segregation of wells into impacted or unimpacted categories to develop probability distributions and summary statistics for each constituent evaluated. The formulated approaches were applied to groundwater monitoring data for the U.S. Department of Energy Savannah River Site facility, and results for four representative constituents (aluminum, arsenic, mercury, and tritium) are discussed.     

Fuzzy rule-based modelling for human health risk from naturally occurring radioactive materials in produced water

Produced water, discharged from offshore oil and gas operations, contains chemicals from formation water, condensed water, and any chemical added down hole or during the oil/water separation process. Although, most of the contaminants fall below the detection limits within a short distance from the discharge port, a few of the remaining contaminants including naturally occurring radioactive materials (NORM) are of concern due to their bioavailability in the media and bioaccumulation characteristics in finfish and shellfish species used for human consumption. In the past, several initiatives have been taken to model human health risk from NORM in produced water. The parameters of the available risk assessment models are imprecise and sparse in nature. In this study, a fuzzy possibilistic evaluation using fuzzy rule based modeling has been presented. Being conservative in nature, the possibilistic approach considers possible input parameter values; thus provides better environmental prediction than the Monte Carlo (MC) calculation. The uncertainties of the input parameters were captured with fuzzy triangular membership functions (TFNs). Fuzzy if-then rules were applied for input concentrations of two isotopes of radium, namely (226)Ra, and (228)Ra, available in produced water and bulk dilution to evaluate the radium concentration in fish tissue used for human consumption. The bulk dilution was predicted using four input parameters: produced water discharge rate, ambient seawater velocity, depth of discharge port and density gradient. The evaluated cancer risk shows compliance with the regulatory guidelines; thus minimum risk to human health is expected from NORM components in produced water.     

Social dimensions of mining: Research,policy and practice challenges for the minerals industry in Australia

The social dimensions of the mining industry are increasingly acknowledged as critical to business success, yet remain the least understood aspect of the business concept of sustainable development—the ‘triple bottom line’ of economy, environment and society.