PM10 concentration levels at an urban and background site in Cyprus: The impact of urban sources and dust storms

Air quality in Cyprus is influenced by both local and transported pollution, including desert dust storms. We examined PM₁₀ concentration data collected in Nicosia (urban representative) from April 1, 1993, through December 11, 2008, and in Ayia Marina (rural background representative) from January 1, 1999, through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM₁₀ concentrations, meteorological records, and satellite data were used to identify dust storm days. We investigated long-term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM₁₀ concentrations ranged from 50.4 to 63.8 μg/m³ and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m³ every year. A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000–2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM₁₀ was 24.0 (0.4) μg/m³. The study of yearly trends showed that PM₁₀ levels in Nicosia decreased from 59.4 μg/m³ in 1993 to 49.0 μg/m³ in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m³, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM₁₀ concentrations during desert dust storms were around 100 μg/m³ since 2000 and much higher in earlier years. Despite the large impact of dust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM₁₀ limit.

ImplicationsThis paper examines PM₁₀ concentrations in Nicosia, Cyprus, from 1993 to 2008. The decrease in PM₁₀ levels in Nicosia suggests that the implementation of traffic emission control policies in Cyprus has been effective. However, particle levels still exceeded the European Union annual standard, and dust storms were responsible for a small fraction of the daily PM₁₀ limit exceedances. Other natural particles that are not assessed in this study, such as resuspended soil and sea salt, may be responsible in part for the high particle levels.     

Volatile Organic Compounds from Coal Tar and Soil Vapor Samples at MGP Sites

This study characterized organic compounds found in New York State manufactured gas plant (MGP) coal tar vapors using controlled laboratory experiments from four separate MGP sites. In addition, a limited number of deep (0.3–1.2 m above coal tar) and shallow (1.2–2.4 m above coal tar) soil vapor samples were collected above the in situ coal tar source at three of these sites. A total of 29 compounds were consistently detected in the laboratory-generated coal tar vapors at 50°C, whereas 24 compounds were detected at 10°C. The compounds detected in the field sample results were inconsistent with the compounds found in the laboratory-generated samples. Concentrations of compounds in the shallow soil vapor sample were either non-detectable or substantially lower than those found in deeper samples, suggesting attenuation in the vadose zone. Laboratory-generated data at 50°C compared the (% non-aromatic)/(% aromatic) ratio and indicated that this ratio may provide good discrimination between coal tar vapor and common petroleum distillates.     

Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists

Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10 % of the total concentrations of Bio-TEQs.     

Development of aquatic life criteria in China: viewpoint on the challenge

While more developed countries have a well-established systems to develop water quality criteria (WQC), little research has been done on the adequacy of the current WQC to protect endemic species of China. In order to maintain the health of aquatic ecosystems in China, a series of projects to establish national WQC based on regional characteristics has recently been initiated. However, the establishment of a completely novel methodology would be costly and time consuming. Also, due to the similarities in physiologies and natural histories of classes of aquatic organisms, there is no reason to believe that WQC would not be sufficient to protect unique species in China. This review was undertaken to identify key outstanding issues regarding establishment of aquatic life criteria (ALC) to be applied in China, including prioritization of chemicals, test species, mode of action, field/semi-field data, and methods of aggregating the information and calculating the ALC. This was used to identify the principle issues that need to be addressed in order to better understand the methods for development of criteria for the protection of aquatic life and provide a reference to China and other developing countries committed to the establishment of their own WQC system.     

A comparison of statistical methods for deriving freshwater quality criteria for the protection of aquatic organisms

Species sensitivity distributions (SSDs) are increasingly used in both ecological risk assessment and derivation of water quality criteria. However, there has been debate about the choice of an appropriate approach for derivation of water quality criteria based on SSDs because the various methods can generate different values. The objective of this study was to compare the differences among various methods. Data sets of acute toxicities of 12 substances to aquatic organisms, representing a range of classes with different modes of action, were studied. Nine typical statistical approaches, including parametric and nonparametric methods, were used to construct SSDs for 12 chemicals. Water quality criteria, expressed as hazardous concentration for 5 % of species (HC₅), were derived by use of several approaches. All approaches produced comparable results, and the data generated by the different approaches were significantly correlated. Variability among estimates of HC₅ of all inclusive species decreased with increasing sample size, and variability was similar among the statistical methods applied. Of the statistical methods selected, the bootstrap method represented the best-fitting model for all chemicals, while log-triangle and Weibull were the best models among the parametric methods evaluated. The bootstrap method was the primary choice to derive water quality criteria when data points are sufficient (more than 20). If the available data are few, all other methods should be constructed, and that which best describes the distribution of the data was selected.     

Screening Capsicum chinense fruits for heavy metals bioaccumulation

Elevated concentrations of heavy metals in edible plants could expose consumers to excessive levels of potentially hazardous chemicals. Sixty-three accessions (genotypes) of Capsicum chinense Jacq, collected from 8 countries of origin were grown in a silty-loam soil under field conditions. At maturity, fruits were collected and analyzed for seven heavy metals (Cd, Cr, Ni, Pb, Zn, Cu, and Mo) concentrations. The main objectives of this investigation were: 1) to determine the concentrations of seven heavy metals in the soil and monitor their accumulation in mature fruits, 2) to categorize the pepper accessions as low or high heavy metal accumulators, and 3) to determine if heavy metal content of the pepper fruit was lower than the permitted limits. Concentrations and relative proportions of heavy metals in pepper fruits of C. chinense varied among accessions. Fruits of Plant Introduction (PI) 355820 accumulated significant concentrations of Cd (0.47 μ g g^?1dry fruit). PI-260522 accumulated the highest concentration of Pb (2.12 μ g g^?1 dry fruit) among the 63 accessions tested. This accession (PI-260522) contained about twice the Pb limit on a fresh weight basis. Among the 63 accessions analyzed, PI-238051 contained the highest levels of Ni (17.2 μ g g^?1). We concluded that high accumulator genotypes may be useful for phytoremediation, while, low accumulator accessions might be appropriate selections for growing on Cd-, Pb-, or Ni-contaminated soils to prevent potential human exposure to heavy metals and health hazards through the food chain.     

Wild tomato leaf extracts for spider mite and cowpea aphid control

Glandular trichomes on the leaves of wild tomato, L. hirsutum f. hirsutum Mull, also known as Solanum habrochaites (Solanaceae), synthesize and accumulate high levels of methyl ketones (MKs). L. hirsutum accession LA 407, having high concentration of MKs, was grown from seeds under greenhouse conditions. Four MKs (2-undecanone, 2-dodecanone, 2-tridecanone, and 2-pentadecanone) were screened for their toxicity to spider mites, Tetranychus urticae Koch and cowpea aphids, Aphis craccivora Koch. The objectives of this investigation were to: (1) develop a bioassay for testing MKs on spider mite and cowpea aphid mortality and (2) compare the efficacies of wild tomato leaf crude extracts and pure standard materials of MKs against spider mite and cowpea aphid mortality. Our results revealed that spider mites are most sensitive to 2-tridecanone (LC₅₀ = 0.08 μmole cm^?2 of treated leaf surface) and least sensitive to 2-undecanone (LC₅₀ = 1.5 μmole cm^?2 of treated leaf surface) 4 h after treatment. Similarly, 2-tridecanone caused greatest mortality (LC₅₀ = 0.2 μmole cm^?2 of treated leaf surface), whereas 2-undecanone caused the lowest morality (LC₅₀ = 0.48 μmole cm^?2 of treated surface) of cowpea aphid. We concluded that all MKs tested in this investigation are toxic to spider mites and aphids. 2-Tridecanone is more effective in killing mites and aphids compared to other MKs. Toxicity of crude extracts, prepared from the leaves of L. hirsutum accession LA 407, to spider mites and cowpea aphids revealed greater mortality compared to a combined mixture of MKs standard material (used at the same concentration as found on LA 407 leaves). This indicates that in addition to MKs, other unidentified compounds in LA 407 leaf extract also have pesticidal properties. Accordingly, leaf extracts of LA 407 could be explored in crop protection, and they might open a new area of MK formulations and discovery of biorational alternatives for pest control in agricultural fields.     

Rotary Kiln Incineration III. An Indepth Study—Kiln Exit/Afterburner/Stack Train and Kiln Exit Pattern Factor Measurements During Liquid CCl4 Processing

Temperature and stable species concentration data are presented from various locations within a full-scale rotary kiln incinerator firing natural gas/carbon tetrachloride/air. The data are being collected as part of a cooperative program involving university, industry and government participation. The overall goal of the program is to develop a more sophisticated understanding of and a predictive capability for rotary kiln and afterburner performance as influenced by basic design and operational parameters. Non-uniformities in stable species and temperature exist for this particular kiln, at the kiln exit, under certain operating conditions. Flow perturbations from within the kiln were found to persist into the afterburner, but not into the stack. High destruction and removal efficiencies (DRE’s) were achieved under the operating conditions of these tests through adequate secondary combustion processing.     

Rotary Kiln Incineration IV. An Indepth Study— Kiln Exit,Transition and Afterburner Sampling During Liquid CCl4 Processing

Detailed temperature and stable species concentration data are presented from the kiln exit, transition section and afterburner of a full-scale incinerator facility firing natural gas/carbon tetrachloride/air. The data are collected as part of a cooperative program involving university, industry and government participation. The overall goal of the program is to develop an understanding and predictive capability for rotary kiln and afterburner performance as influenced by basic design and operational parameters. The data demonstrate that nonuniformities in stable species and temperature exist, under certain operating conditions, at the kiln exit in the vertical direction only. Measurements from the transition section indicate that non-uniformities may exist within this region under certain operating conditions. Flow perturbations from within the kiln can persist into the afterburner, although the degree of nonuniformity is substantially reduced compared to either the kiln or transition sections. High destruction and removal efficiencies were achieved under all operating conditions of these tests through a combination of kiln and secondary combustion processing.