Verification of diffusive and pumped samplers for volatile organic compounds using a controlled atmosphere test facility

There is a requirement to verify the performance of sorbent-based passive or active samplers and to extend their use, where possible, to monitor volatile organic compounds (VOCs) that are known to be photochemical ozone pre-cursors or are relevant to the activities of the petrochemical industry. We report measurements of the 14-day diffusive uptake rates for the VOCs: i-butane (2-methyl propane), n-butane, i-pentane (2-methyl butane), n-pentane, n-hexane, benzene, toluene, and m-xylene (at environmental level concentrations) for industry standard axial samplers (Perkin–Elmer-type samplers) containing the sorbents Carbopack-X, -Z, -B or Tenax-TA. We also present data on back-diffusion, blank levels, and storage for the above sorbents, and describe the simultaneous use of the sorbent Carbopack-X for pumped sampling of certain VOCs. The results were obtained by dosing samplers in a controlled atmosphere test facility (CATFAC) operating under well-defined conditions of concentration, nominal temperature of 20 °C, wind speed of 0.5 m s^?1, and relative humidities of 0% and 80%. Field measurements were also obtained to provide supplementary data to support the laboratory study. Results are compared to existing published data, where these are available.     

Overcoming latecomer disadvantage through learning processes: Taiwan’s venture into wind power development

Research into national innovation systems (NISs) has received extensive academic and policy attention, and is especially relevant with latecomer countries seeking to innovate in challenging industrial environments. In playing catch up with their early industrializing counterparts, methods of learning take on increased importance in determining industrial success for latecomers. The wind turbine technology innovation system is one that is highly dependent on both the extent of the national learning processes and the strength of the national social-institutional setting. This research investigates the case of Taiwan, a country which has embarked on a program to build its national innovative capacity in wind turbine technologies with specific emphasis on Taiwan’s social sector. Within this system, the spotlight will be on four types of learning processes that interplay during wind turbine development: learning by searching, learning by doing, learning by using, and learning by interacting. Through a case study of the emergence of Taiwan’s burgeoning large-scale wind power technology initiatives, the paper aims to add to the understanding on how methods of learning impact upon the success of innovation systems. The findings show that the industry’s future prospects are constrained because of the limited learning by interacting processes between turbine component producers, turbine owners, and researchers and because of weaknesses in the institutional framework. This research also recognizes the importance that culture has on dominant forms of learning.     

The effect of certain intrinsic and extrinsic variables on the acute toxicity of selected organophosphorus insecticides to the mummichog,Fundulus heteroclitus

Abstract

The acute toxicity of two organophosphorus (OP) insecticides, azinphosmethyl and acephate, was evaluated in the mummichog, Fundulus heteroclitus. In addition, the effects of certain intrinsic (sex) and extrinsic (salinity and multiple toxicant interraction) variables on the toxic response were also investigated. Azinphosmethyl was by far the most toxic of the two OP insecticides with a 96h LC50 ～ 100,000 x lower than that for acephate. Slight sex differences were observed in the sensitivity of mummichogs to each of the OP insecticides with male fish being marginally more sensitive. Significant effects of low salinity stress were observed only with acephate exposure and, in this case, low salinity appeared to be slightly protective. In general, all of the insecticide mixtures (azinphosmethyl/endosulfan, azinphosmethyl/fenvalerate and acephate/fenvalerate) tested exhibited simple additive toxicity.     

The chronic toxicity of fenoxycarb to larvae of the grass shrimp,Palaemonetes pugio

Abstract

This study examined effects of fenoxycarb, a carbamate insecticide, on larvae of the grass shrimp, Palaemonetes pugio. In laboratory experiments, grass shrimp larvae were exposed to fenoxycarb from hatch to postlarval metamorphosis in a chronic, static renewal bio assay. LC50's ranged from 0.92 mg/L at 96 h to 0.35 mg/L at the end of the study (24 days). In assessing sublethal effects of fenoxycarb, postlarval emergence was significantly (p < 0.05) reduced in exposed grass shrimp as compared with controls, and the time to reach postlarval status was significantly (p < 0.05) increased in exposed grass shrimp. Significant differences were not found in other sublethal parameters including postlarval dry weight and intermolt duration. Analysis of fenoxycarb from spiked seawater samples showed concentrations declined by 32 to 42% after 24 h.     

Biological nitrogen and carbon removal in a gravity flow biomass concentrator reactor for municipal sewage treatment

A novel membrane system, the Biomass Concentrator Reactor (BCR), was evaluated as an alternative technology for the treatment of municipal wastewater. Because the BCR is equipped with a membrane whose average poresize is 20 μm (18–28 μm), the reactor requires low-pressure differential to operate (gravity). The effectiveness of this system was evaluated for the removal of carbon and nitrogen using two identical BCRs, identified as conventional and hybrid, that were operated in parallel. The conventional reactor was operated under full aerobic conditions (i.e., organic carbon and ammonia oxidation), while the hybrid reactor incorporated an anoxic zone for nitrate reduction as well as an aerobic zone for organic carbon and ammonia oxidation. Both reactors were fed synthetic wastewater at a flow rate of 71 L d^?1, which resulted in a hydraulic retention time of 9 h. In the case of the hybrid reactor, the recycle flow from the aerobic zone to the anoxic zone was twice the feed flow rate. Reactor performance was evaluated under two solids retention times (6 and 15 d). Under these conditions, the BCRs achieved nearly 100% mixed liquor solids separation with a hydraulic head differential of less than 2.5 cm. The COD removal efficiency was over 90%. Essentially complete nitrification was achieved in both systems, and nitrogen removal in the hybrid reactor was close to the expected value (67%).     

Partitioning of metals in a degraded acid sulfate soil landscape: influence of tidal re-inundation

The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1 m) and the unoxidised sub-soil materials (1.3-1.5 m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the “labile”, “acid-soluble”, “organic”, “crystalline oxide”, “pyritic” and “residual” fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The “acid-soluble”, “organic” and “pyritic” fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite.     

Emission factors for high-emitting vehicles based on on-road measurements of individual vehicle exhaust with a mobile measurement platform

Fuel-based emission factors for 143 light-duty gasoline vehicles (LDGVs) and 93 heavy-duty diesel trucks (HDDTs) were measured in Wilmington, CA using a zero-emission mobile measurement platform (MMP). The frequency distributions of emission factors of carbon monoxide (CO), nitrogen oxides (NO(x)), and particle mass with aerodynamic diameter below 2.5 microm (PM2.5) varied widely, whereas the average of the individual vehicle emission factors were comparable to those reported in previous tunnel and remote sensing studies as well as the predictions by Emission Factors (EMFAC) 2007 mobile source emission model for Los Angeles County. Variation in emissions due to different driving modes (idle, low- and high-speed acceleration, low- and high-speed cruise) was found to be relatively small in comparison to intervehicle variability and did not appear to interfere with the identification of high emitters, defined as the vehicles whose emissions were more than 5 times the fleet-average values. Using this definition, approximately 5% of the LDGVs and HDDTs measured were high emitters. Among the 143 LDGVs, the average emission factors of NO(x), black carbon (BC), PM2.5, and ultrafine particle (UFP) would be reduced by 34%, 39%, 44%, and 31%, respectively, by removing the highest 5% of emitting vehicles, whereas CO emission factor would be reduced by 50%. The emission distributions of the 93 HDDTs measured were even more skewed: approximately half of the NO(x) and CO fleet-average emission factors and more than 60% of PM2.5, UFP, and BC fleet-average emission factors would be reduced by eliminating the highest-emitting 5% HDDTs. Furthermore, high emissions of BC, PM2.5, and NO(x) tended to cluster among the same vehicles.     

The survey of living conditions in the Arctic (SLiCA): A comparative sustainable livelihoods assessment

The Arctic is a region of the world experiencing extremely rapid climatic and social change. Indigenous communities have faced similar challenges for millennia and have historically demonstrated remarkable resilience to socioecological perturbations. In contemporary contexts, however, it appears that the pace and extent of change is overwhelming the adaptive capacities of many indigenous communities. Scholars recently completed a survey of living conditions spanning the circumpolar Arctic to quantitatively document the impacts of social and ecological stress across regions. The database they created is called the Survey of Living Conditions in the Arctic or SLiCA. This article explores the utility of using this dataset to compare livelihood systems across three sub-regions of Alaska and four sub-regions within the Chukotka Autonomous Okrug of the Russian Federation. The results point out that livelihood systems in Chukotka have a substantially lower level of sustainability than in Northwest Alaska due to the high prevalence of vulnerable households.