Aquatic toxicity of cartap and cypermethrin to different life stages of Daphnia magna and Oryzias latipes

Cartap and cypermethrin, which are among the most widely used pesticides in many countries, are considered safe because of their low mammalian toxicity and their low persistence in the environment. However, recent findings of endocrine-disrupting effects and developmental neurotoxicity have raised concerns about the potential ecological impacts of these pesticides. We evaluated the aquatic toxicity of cartap [S,S′-(2-dimethylaminotrimethylene) bis(thiocarbamate), unspecified hydrochloride] and cypermethrin [(RS)-alpha-cyano-3-phenoxybenzyl-(1RS,3RS,1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate], both individually and combined, on different life stages of the freshwater cladoceran Daphnia magna and a freshwater teleost, Japanese medaka (Oryzias latipes). The 96-hr Daphnia median effective concentrations (EC50s) for cartap and cypermethrin were 91.0 μ g/L and 0.00061 μ g/L, respectively. Rapid recovery of Daphnia was observed after short-term pulsed exposure to cartap and cypermethrin; there were no adverse effects on reproduction or survival 20 d after a 24 hr exposure to cartap up to 1240 μ g/L and cypermethrin up to 1.9 μ g/L. Chronic continuous exposure (for 21 d) of 7-d-old Daphnia to cypermethrin significantly reduced the intrinsic population growth rate in a concentration-dependent manner. However, because the intrinsic population growth rates were all above zero, populations did not decrease even at the highest experimental concentration of 200 ng/L. Exposure of Daphnia neonates (< 24 hr old) to cypermethrin for 21 d caused significant, sub-lethal reproduction-related problems, such as increased time to first brood, reduced brood size, and reduced total brood number, at 0.0002, 0.002, and 0.2 ng/L cypermethrin, but the intrinsic population growth rate was not significantly affected. Oryzias latipes was relatively more resistant to both pesticides. In particular, embryos appeared to be more resistant than juveniles or adults, which may be partly due to the protective role of the chorion. The incidence of larval fish deformity was significantly higher after a 96 hr exposure to as low as 250 μ g/L of cartap or 40 μ g/L of cypermethrin. The mixture of both compounds showed no synergistic toxicity. The extremely high acute-to-chronic ratio suggests that the standard acute lethal toxicity assessment might not reflect the true environmental hazards of these frequently used pesticides. Ecological hazard assessments of long-term low dose or pulsed exposures to cartap and cypermethrin may reveal more realistic consequences of these compounds in surface water.     

Direct assessment of international consistency of standards for ground-level ozone: strategy and implementation toward metrological traceability network in Asia

An international exercise to directly assess consistency of standards for ground-level ozone in East Asia was conducted as part of the East Asian Regional Experiment 2005 (EAREX 2005) in the framework of the Atmospheric Brown Clouds (ABC) project. Ten organizations collaboratively participated in the intercomparison. Four groups representing Japan, Korea, Hong Kong, and Taiwan made comparisons at the Gosan super observatory, Jeju Island, Korea, in March 2005, with ozone instruments calibrated to their national standards, and four Japanese groups made off-site comparisons with laboratory-level standards. All comparisons generally indicated good agreement with the standard reference photometer (SRP) 35, built by the National Institute of Standards and Technology (USA) and maintained by the National Institute for Environmental Studies (Japan). The assessment was expanded to measurement networks contributing to the World Meteorological Organization's Global Atmospheric Watch (WMO/GAW) program as part of off-site comparisons, and excellent agreement was achieved. These efforts contribute to propagating traceability of the national metrology standards among the atmospheric science community, to ensuring comparability of the existing ozone measurements, and to establishing an integrated network of air quality monitoring in Asia.     

Effect of mixing on NO removal in the selective noncatalytic reduction reaction process

The effect of mixing of NH₃ and NO on the selective noncatalytic reduction (SNCR) reaction was investigated using a bench-scale reactor. Three different experimental conditions were compared for the removal of NO in the bulk gas with NH₃, a reducing agent, by means of mixing and contacting. The temperature that gave the highest NO removal efficiency was about 800°C when NH₃ was injected with air or NH₃ was premixed and air was injected. It is suggested that control of mixing of the reducing agent and the injection conditions could be a good way to increase NO removal efficiency as well as to lower the reaction temperature. When NH₃ was injected with air, the NO removal efficiency increased with increasing injected air flow if the initial NO concentration was low, whereas for high NO concentrations, the NO removal efficiency slightly increased up to an injected air flow rate of 100 ml/min. A proposed mixed-flow model can be used as a prediction tool for the NO removal efficiency covering various conditions of the real SNCR process.     

Mitigating methane emissions and air intrusion in heterogeneous landfills with a high permeability layer

Spatially variable refuse gas permeability and landfill gas (LFG) generation rate, cracking of the soil cover, and reduced refuse gas permeability because of liquid addition can all affect CH₄ collection efficiency when intermediate landfill covers are installed. A new gas collection system that includes a near-surface high permeability layer beneath the landfill cover was evaluated for enhancing capture of LFG and mitigating CH₄ emissions. Simulations of gas transport in two-dimensional domains demonstrated that the permeable layer reduces CH₄ emissions up to a factor of 2 for particular spatially variable gas permeability fields. When individual macrocracks formed in the cover soil and the permeable layer was absent, CH₄ emissions increased to as much as 24% of the total CH₄ generated, double the emissions when the permeable layer was installed. CH₄ oxidation in the cover soil was also much more uniform when the permeable layer was present: local percentages of CH₄ oxidized varied between 94% and 100% across the soil cover with the permeable layer, but ranged from 10% to 100% without this layer for some test cases. However, the permeable layer had a minor effect on CH₄ emissions and CH₄ oxidation in the cover soil when the ratio of the gas permeability of the cover soil to the mean refuse gas permeability ?0.05. The modeling approach employed in this study may be used to assess the utility of other LFG collection systems and management practices.     

Heavy metal immobilization in soil near abandoned mines using eggshell waste and rapeseed residue

Heavy metal contamination of agricultural soils has received great concern due to potential risk to human health. Cadmium and Pb are largely released from abandoned or closed mines in Korea, resulting in soil contamination. The objective of this study was to evaluate the effects of eggshell waste in combination with the conventional nitrogen, phosphorous, and potassium fertilizer (also known as NPK fertilizer) or the rapeseed residue on immobilization of Cd and Pb in the rice paddy soil. Cadmium and Pb extractabilities were tested using two methods of (1) the toxicity characteristics leaching procedure (TCLP) and (2) the 0.1 M HCl extraction. With 5 % eggshell addition, the values of soil pH were increased from 6.33 and 6.51 to 8.15 and 8.04 in combination with NPK fertilizer and rapeseed residue, respectively, compared to no eggshell addition. The increase in soil pH may contribute to heavy metal immobilization by altering heavy metals into more stable in soils. Concentrations of TCLP-extracted Cd and Pb were reduced by up to 67.9 and 93.2 % by addition of 5 % eggshell compared to control. For 0.1 M HCl extraction method, the concentration of 0.1 M HCl-Cd in soils treated with NPK fertilizer and rapeseed residue was significantly reduced by up to 34.01 and 46.1 %, respectively, with 5 % eggshell addition compared to control. A decrease in acid phosphatase activity and an increase in alkaline phosphatase activity at high soil pH were also observed. Combined application of eggshell waste and rapeseed residue can be cost-effective and beneficial way to remediate the soil contaminated with heavy metals.     

Laboratory-scale application of fiber optic transflection dip probe (FOTDP) for in situ monitoring of gas phase ozone in unsaturated porous media

A fiber optic transflection dip probe (FOTDP) system was developed for in situ and real-time monitoring of the transport of gas phase ozone in unsaturated porous media. A unique property of this system is the employment of a dip probe, which is inserted within the porous media. At the probe's tip, incoming light interacts with gas phase ozone and is partially reflected back into the probe by a mirror attached to the tip. Calibration of the FOTDP system was successfully carried out with various ozone concentrations using a column packed with glass beads. The ozone breakthrough curves (BTCs) were obtained by converting normalized UV intensities into gas phase ozone concentrations. The FOTDP system worked well for in situ monitoring of gas phase ozone using a column packed with sand under various water saturations in the presence of SOM and reflected the ideal transport phenomena of gas phase ozone for various flow rates.     

Postural evaluation in a poultry farm for broiler chickens

The goal of this study was to evaluate working postures in 9 operations of poultry farming for broiler chickens for 14 body segments with 4 categories, and for fingers with 14 categories. Overall, the farmers commonly bent almost all their body segments and used power grips. The operations of cleaning with water wand and inspecting chickens seemed light work because the farmers walked around most of their working time. The operations of detaching base from hanging feeder and attaching base to hanging feeder had the farmers continue squatting to handle the feeders close to the floor. The farmers also repeatedly bent their trunks in shoveling feces, unloading a box of chicks, and releasing chicks. A power grip was frequently observed due to using tools with round handles. Workplace design to raise working height would be necessary for a better working environment for broiler farmers.     

One-Pot Reaction of Waste PET to Flame Retardant Polyurethane Foam,via Deep Eutectic Solvents-Based Conversion Technology

Depolymerization of polyethylene terephthalate (PET) is a promising technology for producing recycled monomers. Using a deep eutectic solvent (DES)-based catalyst, the PET glycolysis process produces bis-(2-hydroxyethylene terephthalate) (BHET). This recycled monomer reacts with isocyanate and forms polyurethane foam (PUF). The DES-based one-pot reaction is advantageous because it is a low-energy process that requires relatively lower temperatures and reduced reaction times. In this study, choline chloride/urea, zinc chloride/urea, and zinc acetate/urea based DESs were adopted as DES catalysts for glycolysis. Subsequently, the conversion of PET, BHET yield, and OH values were evaluated. Both filtered and unfiltered reaction mixtures were used as polyols for PUF polymerization after characterization of the acid and hydroxyl values of the polyols, as well as the NCO (–N=C=O) value of isocyanate. In the case of unfiltered reaction mixtures, PUF was obtained via a one-pot reaction, which exhibited higher thermal stability than PUF made from the filtered polyols. This outcome indicated that oligomeric BHET containing many aromatic moieties in unfiltered polyols contributes to the thermal stability of PUF. This environmentally friendly and relatively simple process is an economical approach for upcycling waste PET.

     

Is risk analysis a useful tool for improving process safety?

To improve safety one has to know where risks are. For determining risks, hazards have to be identified and representative accident scenarios defined. This needs effort and technique. Man is quite limited in foresight without having experience and lessons from the past. For knowing the risk of an incidental, undesired event both its severity and probability has to be estimated. Then ways to reduce risk become clear. In a process plant risks are many and it is not possible to remove them all. One has to attribute priorities. Intuitive and qualitative methods can do much, but plant complexity may be large and communication on risk may become difficult without formal methodology. Quantitative risk analysis offers much, but has its weaknesses and drawbacks. The required effort is considerable, specialists are needed, and variability in answers is large. Yet, a model built to go along with the life of an installation and updated periodically may be very useful. This paper presents an overview of the demand, problems encountered, possible remedies, and an outlook on useful improvement and extension of risk analysis methodology, including decision making.