A comparison of mixture toxicity assessment: examining the chronic toxicity of atrazine, permethrin and chlorothalonil in mixtures to Ceriodaphnia cf. dubia

Pesticides predominantly occur in aquatic ecosystems as mixtures of varying complexity, yet relatively few studies have examined the toxicity of pesticide mixtures. Atrazine, chlorothalonil and permethrin are widely used pesticides that have different modes of action. This study examined the chronic toxicities (7-d reproductive impairment) of these pesticides in binary and ternary mixtures to the freshwater cladoceran Ceriodaphnia cf. dubia. The toxicity of the mixtures was compared to that predicted by the independent action (IA) model for mixtures, as this is the most appropriate model for chemicals with different modes of action. Following this they were compared to the toxicity predicted by the concentration addition (CA) model for mixtures. According to the IA model, the toxicity of the chlorothalonil plus atrazine mixture conformed to antagonism, while that of chlorothalonil and permethrin conformed to synergism. The toxicity of the atrazine and permethrin mixture as well as the ternary mixture conformed to IA implying there was either no interaction between the components of these mixtures and/or in the case of the ternary mixture the interactions cancelled each other out to result in IA. The synergistic and antagonistic mixtures deviated from IA by factors greater than 3 and less than 2.5, respectively. When the toxicity of the mixtures was compared to the predictions of the CA model, the binary mixture of chlorothalonil plus atrazine, permethrin plus atrazine and the ternary mixture all conformed to antagonism, while the binary mixture of chlorothalonil plus permethrin conformed to CA. Using the CA model provided estimates of mixture toxicity that did not markedly underestimate the measured toxicity, unlike the IA model, and therefore the CA model is the most suitable to use in ecological risk assessments of these pesticides.     

Methane and carbon dioxide emission from two pig finishing barns

Agricultural activities are an important source of greenhouse gases. However, comprehensive, long-term, and high-quality measurement data of these gases are lacking. This article presents a field study of CH(4) and CO(2) emission from two 1100-head mechanically ventilated pig (Sus scrofa) finishing barns (B1 and B2) with shallow manure flushing systems and propane space heaters from August 2002 to July 2003 in northern Missouri. Barn 2 was treated with soybean oil sprinkling, misting essential oils, and misting essential oils with water to reduce air pollutant emissions. Only days with CDFB (complete-data-full-barn), defined as >80% of valid data during a day with >80% pigs in the barns, were used. The CH(4) average daily mean (ADM) emission rates were 36.2 +/- 2.0 g/d AU (ADM +/- 95% confidence interval; animal unit = 500 kg live mass) from B1 (CDFB days = 134) and 28.8 +/- 1.8 g/d AU from B2 (CDFB days = 131). The CO(2) ADM emission rates were 17.5 +/- 0.8 kg/d AU from B1 (CDFB days = 146) and 14.2 +/- 0.6 kg/d AU from B2 (CDFB days = 137). The treated barn reduced CH(4) emission by 20% (P < 0.01) and CO(2) emission by 19% (P < 0.01). The CH(4) and CO(2) released from the flushing lagoon effluent were equivalent to 9.8 and 4.1% of the CDFB CH(4) and CO(2) emissions, respectively. The emission data were compared with the literature, and the characteristics of CH(4) and CO(2) concentrations and emissions were discussed.     

Isolation and identification of potential fungal species for spent engine lubrication oil remediation in Peninsular Malaysia

Improper disposal and spills of spent engine oil into the environment can result in contamination, which eventually affects humans through the food chain. Mycoremediation is an effective and inexpensive alternative to clean up spent engine oil contamination. In recent work, the potential effectiveness of fungi for degrading spent engine oil was confirmed, with the species identified through molecular identification. Fungi that were able to grow in Bushnell Haas Broth supplied with spent engine oil were identified with the potential to utilize spent engine oil as a carbon source. Six species of fungi namely Penicillium simplicissimum, Aspergillus nidulans, Aspergillus niger, Trichoderma longibrachiatum, Aspergillus ustus, and Aspergillus flavus were successfully identified in this study. Over a course of seven days, P. simplicissimum (21.11 percent) was identified as the most effective fungi in degrading spent engine oil, followed by A. nidulans (17.75 percent), A. niger (15.85 percent), T. longibrachiatum (15.12 percent), A. ustus (15.02 percent), and A. flavus (11.80 percent). As these species of fungi were isolated from the natural environment in Peninsular Malaysia, the potential of using these fungi as mycoremediation of spent engine oil was therefore confirmed.     

Fatigue Life Behaviour of Glass/Kenaf Woven-Ply Polymer Hybrid Biocomposites

Investigation on the fatigue life of hybrid composites is critical to extend their applications and acceptance among industries; however, there is a lack of research focus on fatigue performance of the hybrid composite. In this study, the fatigue life of glass/kenaf woven-ply hybrid composite with thermoplastic and thermoset polymer matrix was investigated. Hybrid composites consist of two different fibre configurations: kenaf/glass/kenaf and glass/kenaf/glass. Thermoplastic hybrid composites were manufactured through the hot press moulding compression method, while thermoset hybrid composites were fabricated through the vacuum-assisted resin infusion method. The tensile strength and fatigue strengths of the kenaf/glass/kenaf composite have been identified to be significantly lower than those of the glass/kenaf/glass composite regardless of the types of matrix used. However, thermoplastic-based kenaf/glass/kenaf composites are less fatigue sensitive compared to glass/kenaf/glass composites; however, this phenomenon is vice versa for thermoset composites due to the epoxy matrix, which limits the stiffening effect in natural fibres.     

Radiation exposure to Marine biota around the Fukushima Daiichi NPP

The dose rates for six marine organisms, pelagic fish, benthic fish, mollusks, crustaceans, macroalgae, and polychaete worms, representative in marine ecosystems, have been predicted by the equilibrium model with the measured seawater activity concentrations at three locations around the Fukushima Daiich nuclear power plant after the accident on March 11, 2011. Model prediction showed that total dose rates for the biota in the costal sea reached 4.8E4 μGy/d for pelagic fish, 3.6E6 μGy/d for crustaceans, 3.8E6 μGy/d for benthic fish, 5.2E6 μGy/d for macroalgae, 6.6E6 μGy/d for mollusks, and 8.0E6 μGy/d for polychaete worms. The predicted total dose rates remained above the UNSCEAR’s (United Nations Scientific Committee on the Effect of Atomic Radiation) benchmark level (1.0E4 μGy/d for an individual aquatic organism), for only the initial short period, which seems to be insufficiently long to bring about any detrimental effect on the marine biota at the population level. Furthermore, the total dose rates for benthic fish and crustaceans approximated using the measured activity concentration of the biota and bottom sediment was well below the benchmark level. From these results, it may be concluded that the impact of the ionizing radiation on the marine biota around the Fukushima NPP as a consequence of the accident would be insignificant.     

Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system

Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume of dust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 μm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.

Implications: VOCs and particles have been of interest both in industrial field and public indoor spaces. In this study, a post cyclone (PoC) that utilizes a residual vortex from the mother cyclone was modified by inserting a flow guide and was applied to capture toluene vapor. The device of modified post-cyclone system can be used effectively in simultaneous treatment of gas-solid flow.     

Drying characteristics of sewage sludge using vacuum evaporation and frying

This study was performed to investigate the possibility of utilizing sewage sludge as a fuel. The drying characteristics of sewage sludge were examined by using vacuum evaporation and fry-drying technology in a batch-type rotary evaporator. In addition, the optimal drying conditions of sludge in the vacuum evaporator were investigated in terms of the vacuum pressure, temperature, and oil dosage ratio, etc. Experimental results showed that the moisture content in the sludge decreased with increases in oil/sewage sludge ratio and temperature. Dried sludge fuel (SDF) product could be obtained with on average less than 5% moisture content and a lower heating value of more than 4000 kcal/kg. Considering energy efficiency, we suggest that the optimal operating condition for drying sludge is ?450 mmHg of vacuum, a temperature of 100°C, a drying time of 90 min, and a sludge/oil ratio of 1:1. The SDF product was shaped as granules and fluff-type particles. Evaluated from the perspective of the energy balance and economic considerations, this sludge drying system with vacuum fry drying could be used for effective sludge treatment and the production of SDF.     

Quality Assured Measurements of Animal Building Emissions: Gas Concentrations

Abstract

Comprehensive field studies were initiated in 2002 to measure emissions of ammonia (NH₃), hydrogen sulfide (H₂S), carbon dioxide (CO₂), methane (CH₄), nonmethane hydrocarbons (NMHC), particulate matter <10 µm in diameter, and total suspended particulate from swine and poultry production buildings in the United States.

This paper focuses on the quasicontinuous gas concentration measurement at multiple locations among paired barns in seven states. Documented principles, used in air pollution monitoring at industrial sources, were applied in developing quality assurance (QA) project plans for these studies. Air was sampled from multiple locations with each gas analyzed with one high quality commercial gas analyzer that was located in an environmentally controlled on-farm instrument shelter. A nominal 4 L/min gas sampling system was designed and constructed with Teflon wetted surfaces, bypass pumping, and sample line flow and pressure sensors. Three-way solenoids were used to automatically switch between multiple gas sampling lines with ≥10 min sampling intervals. Inside and outside gas sampling probes were between 10 and 115 m away from the analyzers. Analyzers used chemiluminescence, fluorescence, photoacoustic infrared, and photoionization detectors for NH₃, H₂S, CO₂, CH₄, and NMHC, respectively. Data were collected using personal computer-based data acquisition hardware and software. This paper discusses the methodology of gas concentration measurements and the unique challenges that livestock barns pose for achieving desired accuracy and precision, data representativeness, comparability and completeness, and instrument calibration and maintenance.