Tidal salt marsh sediment in California, USA. Part 1: occurrence and sources of organic contaminants

Surface sediment samples (0-5 cm) from five tidal marshes along the coast of California, USA were analyzed for organic pollutants to investigate their relationship to land use, current distribution within marshes, and possible sources. Among the study areas, Stege Marsh, located in San Francisco Bay, was the most contaminated. Compared to San Francisco Bay, Stege Marsh had much higher levels of organic contaminants such as PCBs (polychlorinated biphenyls), DDTs, and chlordanes. At reference marshes (Tom's Point and Walker Creek in Tomales Bay), organic contaminants in sediments were very low. While PAHs (polycyclic aromatic hydrocarbons) were found at all of the study areas (22-13,600 ng g(-1)), measurable concentrations of PCBs were found only in the sediments from Stege Marsh (80-9,940 ng g(-1)). Combustion related (pyrogenic) high molecular weight PAHs were dominant in sediments from Stege and Carpinteria Marshes, while in sediments from Tom's Point and Walker Creek petroleum related (petrogenic) low molecular weight PAHs and alkyl-substituted PAHs were much more abundant than pyrogenic PAHs. PCB congener patterns in all of the Stege Marsh samples were the same and revealed that Aroclor 1248 was a predominant source. In all marshes, the sum of DDE and DDD accounted for more than 90% of total DDTs, indicating that DDT has degraded significantly. The ratios of p,p'-DDE to p,p'-DDD in sediments from Stege Marsh provide evidence of possible previous use of technical DDD. Chlordane ratios indicated that chlordanes have degraded slightly. Bis(2-ethylhexyl)phthalate (280-32,000 ng g(-1)) was the most abundant phthalate. The data indicates that Stege Marsh may be a source of contaminants that continue to be discharged into San Francisco Bay.     

Preliminary exploration of the relationships between soil characteristics and PAH desorption and biodegradation

Desorption and biodegradation of pyrene (PYR) were investigated and their relationships to soil characteristics were addressed. The results indicated that maximum achievable desorption was 30.2, 10.4, and 1.0 mg/kg for soils that had 1.7, 2.2, and 4.4 wt.% of expandable clays (smectite and vermiculite), respectively. Neither dissolved organic matter (DOM) nor total clay amounts made a good prediction of the desorption trend. Subsequently, the ease of desorption facilitated a faster aqueous biodegradation rate. The slowest aqueous biodegradation rate, 0.02 l/h, was achieved for the soil system that had the greatest amount of expandable clays, whereas the soil containing 1.7% expandable clays only achieved 0.73 l/h. The soil with 2.2% expandable clays depicted 0.41 l/h of aqueous biodegradation rate. A good linear correlation was obtained between maximum achievable desorption and aqueous biodegradation rate (R(2)=0.92). Soil analysis revealed that the total (soil+water) biodegradation reached was 65%, 78.3%, and 81.8% of the initial concentration (100 mg/kg) for the sandy clay loam (Colombian), sandy loam (Ohio), and silty loam (New Mexico) soils, respectively. This biodegradation extent was also in good agreement of expandable clay amount. Although aqueous PYR bioavailability was limited due to the strong association with the expandable clays, microbial movement and adhesion to those clays seemed to result in a great extent of the soil-phase biodegradation.     

Polychlorinated biphenyls (PCBs) in indoor air and in serum among older residents of upper Hudson River communities

A study was conducted to evaluate the association between PCBs in residential indoor air and in the serum of older, long time residents of three upper Hudson River communities. Samples of indoor air and of serum were collected from 170 persons 55 to 74 years of age, and analyzed for PCBs using glass capillary gas chromatography. After adjusting for age, BMI, cigarette smoking, and Hudson River fish consumption with multiple linear regression analysis, the results indicated statistically significant associations between concentrations in indoor air and serum for PCB-28, a lightly chlorinated congener common in air that accumulates in serum, and PCB-105. Duration of exposure was an important factor, since among persons who had lived in their home for 39 years or more, 11 of the 12 most commonly detected congeners were significantly correlated, as was their sum (∑ PCB). Significant associations between indoor air and serum PCB concentrations also were more likely when collected in cooler months and if the two samples were collected within 20 d of each other. The study is among the first to indicate that PCB concentrations characteristic of residential indoor air are associated with a detectable increase in body burden.     

Evaluation and comparison of alarm reset modes in advanced control room of nuclear power plants

An automation function has been widely applied in main control room of nuclear power plants (NPPs). The alarm system of fourth nuclear power plant (FNPP) in Taiwan is also going to be developed with automatic technology that is expected to support the operators’ performance and reduce the number of alarms. In this study, an experiment with a training simulator as an advanced alarm system was conducted to compare the effects of different alarm reset modes on performance and subjective ratings. The objective was to evaluate the practicability of alarm system with only auto-reset function in FNPP. Results revealed that, using the auto-reset mode, participants had lower task load index (TLX) on effort in the first test trial and was more satisfied under multi-task condition. In contrast, using manual reset mode, participants were more satisfied on alarm handling, monitoring, and decision making. In other words, both reset modes are necessary to assist the operator in different aspects, but with only single reset mode is insufficient. The reset function in advanced alarm system therefore should be very flexible.     

Site Representativeness of Urban Air Monitoring Stations

Abstract

This paper describes a statistic to quantify spatial representativeness for the air measurements of an urban fixed-site ambient air monitoring station. The application of such a statistic of representativeness has also been successfully demonstrated by two data sets collected at the Gu-Ting monitoring station in Taipei. By measuring NO2 at 22 sites simultaneously around the Gu-Ting station, the statistic has characterized different degrees of spatial representativeness for nitrogen dioxide (NO2) at various areas and microenvironments surrounding this fixed-site monitoring station. By measuring ambient air concentrations at six sites sequentially around the Gu-Ting station, the statistic has also characterized different degrees of representativeness for particulates less than 10 urn in size—(PM10), carbon monoxide (CO), sulfur dioxide (SO2), ozone (O3), NO2, nitrogen oxides (NOX), nitrogen monoxide (NO), total hydrocarbons (THC), and nonmethane hydrocarbons (NMHQ—at an open area surrounding this fixed-site monitoring station. This statistical method identifies the Gu-Ting station is well representative of outdoor concentrations of all nine air pollutants for a period of three weeks at the areas within a 700 m radius around this station. The indoor NO2 concentrations, however, are not represented by the measurements at the fixed-site monitoring station.     

Emission of heavy metals from animal carcass incinerators in Taiwan

The metal emissions from three incinerators burning different feedstock in Taiwan were characterized in this study. It was found that the Incinerators A and B, treating pig carcasses and animal (including pigs) carcasses, respectively, had much higher metal concentrations in stack flue gases than Incinerator C that combusted medical wastes. However, Incinerator A obtained relative lower metal contents in fly ash and bottom ash than the other two incinerators, mainly because the former used a much lower feedstock rate (although burning at a lower temperature) than the latter. For all the incinerators, (1) Fe, Ni, Pb, and Zn were dominant in both the fly ash and bottom ash while most of the Cd and Pb (more volatile) were present in the fly ash; (2) Fe emission factor was the highest and Zn/Pb/Ni/Cr emission factors were greater than those of Mn/Cd/Cu; (3) the Cu emission factors in bottom ash were relatively higher in comparison with those in fly ash; and (4) indicatory metals were the same (Fe, Zn, Pb, and Cu). The metal emission factors obtained from the livestock incinerators were much higher than those reported from MSW incinerators. Likewise, crematories that burn human cadavers must create similar pollution issues since metal supplements are part of human's normal diets. This causes an environmental concern and this work has important ramifications both in technical and regulatory decisions.     

Dechlorination of trichloroethylene by a steel converter slag amended with Fe(II)

This study aims to assess the feasibility of using slag, byproduct from iron and steel making industries, as a new reactive material for dechlorination reactions and to investigate dechlorination chemistries of the systems containing the slag and Fe(II). Initially, screening experiments were conducted to evaluate various systems containing slags with or without Fe(II). A combination of the steel converter slag and Fe(II) showed a potential to be developed as a reactive material to treat chlorinated organics. Further kinetic studies with the steel converter slag/Fe(II) systems revealed that the dechlorination capacity of the slag/Fe(II) system is comparable to that of zero-valent iron and generally higher than the cement/Fe(II) system. The slag/Fe(II) system can substantially dechlorinate trichloroethylene (TCE) in the neutral pH region, although the dechlorination rate was greatest in the pH region between 12 and 13. TCE reductions in the slag/Fe(II) system were observed to occur through reductive beta-elimination pathways that produce primarily acetylene and no chlorinated intermediates such as vinyl chloride. These results demonstrate that the steel converter slag with Fe(II) has sound characteristics for an alternative reactive medium for subsurface remediation.     

End-of-life batteries management and material flow analysis in South Korea

Analysis of collection and recycling system of end-of-life batteries was examined. Relatively limited fractions of portable batteries were collected by EPR system. More effective and diverse collection pathways should be developed. Consumers increasingly have worn-out batteries as electrical and electronic equipment with new technical developments are introduced into the market and quickly replace older models. As a result, large amounts of end-of-life (EOL) or waste batteries are generated. Such batteries may contain a variety of materials that includes valuable resources as well as toxic elements. Thus, the proper recycling and management of batteries is very important from the perspective of resource conservation and environmental effect. The collection and recycling of EOL batteries is relatively low in South Korea compared to other countries, although an extended producer responsibility (EPR) policy was adopted for battery recycling in 2003. In this study, the management and material flow of EOL batteries is presented to determine potential problems and quantitative flow, based on literature review, site visits to battery recycling facilities, and interviews with experts in the Korea Battery Recycling Association (KBRA), manufacturers, and regulators in government. The results show that approximately 558 tons of manganese-alkaline batteries, the largest fraction among recycling target items, was disposed in landfills or incinerators in 2015, while approximately 2,000 tons of batteries were recovered at a recycling facility by simple sorting and crushing processes. By raising environmental awareness, more diverse and effective collection systems could be established for consumers to easily dispose of EOL batteries in many places. Producers, retailers and distributors in South Korea should also play an important role in the collection of EOL batteries from consumers. Lithium-ion batteries from many electronic devices must be included in the EPR system for resource recovery.     

Incense burning at home and the blood lead level of preschoolers in Taiwan

The growth and intellectual development of children less than 6 years old may be affected by exposure to low levels of lead. To further reduce environmental lead exposure, this study examined possible household-related factors that affect the blood lead levels of Taiwanese children. In total, based on a stratified random sampling strategy, 934 kindergarten students were recruited throughout Taiwan from April to October 2011 after their parents signed a statement of consent. A venous blood sample was drawn from each participant and analyzed for lead content using inductively coupled plasma mass spectrometry. Information on the demographics and household environment of the study subjects was collected by administering a questionnaire (Table 1). The geometric mean lead level in the blood samples of the study subjects was 1.84 μg/dL with a geometric standard deviation of 1.55. The blood lead level was negatively correlated with household income and parental educational levels (p?p?p?p?=?0.0022). Because the health effects of low levels of lead exposure have been reported in recent years and because no consensus has been reached regarding a safety threshold for blood lead level in children, any trivial factor is worth investigating to further prevent lead exposure in children. Incense burning at home is a common traditional religious activity in Taiwan; therefore, more study is warranted to further eliminate the lead content in incense and reduce lead exposure for the families who practice this activity.