A yearlong (December 2003 to February 2005) monitoring program was undertaken for urban roadside measurement of benzene, toluene, ethyl benzene, m- and p-xylene, and o-xylene (BTEX) at three different sites of Kolkata, India. The concentrations of monoaromatic hydrocarbons were found to be sufficiently high. Chemical mass balance model was applied to identify the sources and estimate their percentage contribution. Vehicular exhaust emission was found to be the dominant source of the target compounds and contributed 38.8-44.8% toward total volatile organic compound (VOC) level. Assuming that the vehicular exhaust fraction of the ambient BTEX level was due to the vehicular activity in the adjacent road of the monitoring site, vehicular emission factors for individual VOCs were estimated by running CALINE4 dispersion model in an inverse way. The total emission factor, average for all vehicles, was found to be in the range of 9.1 to 43.1 mg vehicle⁻¹ km⁻¹ for BTEX. From the measured vehicular composition during sampling, the category-wise emission factors for light-duty vehicles (LDVs), medium-duty (MDVs), and heavy-duty vehicles (HDVs), were also estimated by constrained nonlinear regression analysis. The emission factor of benzene for heavy, medium, and light vehicles was found to be 13.4, 21.0, and 31.2 mg vehicle⁻¹ km⁻¹ respectively.

The presence of polylcyclic aromatic hydrocarbons (PAHs) in surface sediments of Barigui River was investigated. PAHs are considered highly toxic and persistent compounds because of their structure. They originate from incomplete combustion of fossil fuels or biomass. The Barigui River crosses the metropolitan region of Curitiba, and some regions are highly polluted and located near the possible sources of pollution. The results showed that concentrations of total PAHs ranged from 44.6 to 880.2 ng g⁻¹, and the highest values were found at the sites previously investigated and identified as critically polluted. At sites located away from the traffic and possible pollution sources, the total PAHs was lower, 44.6 ng g⁻¹. Due to their hydrophobic character, sediments with high silt and clay content retain greater amounts of PAHs. The granulometric composition of the sediments revealed that most of them are composed basically by silt and clay, and those samples showed high concentration of PAHs. The organic carbon content also confirms this observation. The other sites investigated showed a high capacity to adsorb hydrophobic compounds mainly due to the granulometric composition and organic matter that adsorb poorly water soluble compounds. Finally, we found that the main sources of PAHs are petrogenic; however, at some sites, it is hard to confirm this pattern, and possibly, a mixture of the source would be more appropriate.

The paper presents the first comprehensive account of congener profiles of polycyclic aromatic hydrocarbons (PAHs) in intertidal bivalve mollusks [Meretrix meretrix, Macoma birmanica, and Sanguilonaria (Soletellina) acuminata] of Sunderban mangrove wetland (India). The main aim of this work was to use the bivalves as bioindicators of the contamination of the 16 USEPA PAH. The PAH profile in bivalves is largely dominated by a petrogenic fingerprint, with over-imposition of pyrolytic PAH sources, as evidenced by diagnostic molecular ratios. Bioaccumulation factors (BAF) of individual compounds from the sediments were calculated, and it reveals overall higher values in the visceral mass of the bivalves. S acuminata showed significantly higher levels of PAHs, especially the high molecular weight (HMW) PAHs, compared to the other two species as a sensitive indicator of trace organic stress in future monitoring programs.

Quantitative structural activity relationship (QSAR) models are receiving wide use because of new regulations and public scrutiny regarding new compounds entered into commerce. Accordingly, the US Department of Defense (DoD) supported this study to evaluate QSAR modeling for energetic compounds. Four compounds proposed to replace ammonium perchlorate were examined: ammonium di(nitramido)amine (ADNA); 1,3,5,5-tetranitrohexahydropyrimidine (DNNC); 1,3,3,5,7,7-hexanitro-1,5-diazacyclooctane (HCO); and diammonium di(nitramido)dinitroethylene (ADNDNE). Currently used compounds were evaluated as analogues for those under development. Ammonium dinitramide (ADN) was the analogue for ADNA; hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) for DNNC; octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) for HCO; and 1,1-diamino-2,2-dinitroethene (FOX-7) for ADNDNE. QSAR analysis was performed with the US Environmental Protection Agency's Estimation Program Interface (EPI) Suite[trade mark sign]. The comparison of model estimates to literature values ranged from good-to-poor. Results suggested the proposed replacement compounds have low aquatic toxicities and little potential to bioaccummulate, but the uncertainty in the predictions indicates QSAR modeling with EPI Suite[trade mark sign] is only useful for qualitative assessments of these proposed energetic compounds.

This study was initiated to explore the effects of ozone (O₃) exposure on potted wheat roots and soil microbial community function. Three treatments were performed: (1) Air with daily averaged O₃ concentration of 4-10 ppb (control situation, CK), (2) Air plus 8 h averaged O₃ concentration of 76.1 ppb (O₃-1), and (3) Air plus 8 h averaged O₃ concentration of 118.8 ppb (O₃-2). In treatments with elevated O₃ concentration (O₃-1 and O₃-2), the root and shoot biomass were reduced by 25% and 18%, respectively, compared to the control treatment (CK). On the other hand, root activity was significantly reduced by 58% and 90.8% in the O₃-1 and O₃-2 treatments, respectively, compared to CK. The soil microbial biomass was significantly reduced only in the highest O₃ concentration (O₃-2 treatment) in the rhizosphere soil. Soil microbial community composition was assessed under O₃ stress based on the changes in the sole carbon source utilization profiles of soil microbial communities using the Biolog[trade mark sign] system. Principal component analysis showed that there was significant discrimination in the sole-carbon source utilization pattern of soil microbial communities among the O₃ treatments in rhizosphere soil; however, there was none in the bulk soil. In rhizosphere soil, the functional richness of the soil microbial community was reduced by 27% and 38% in O₃-1 and O₃-2 treatments, respectively, compared to CK. O₃-2 treatment remarkably decreased the Shannon diversity index of soil microbial community function in rhizosphere soil, but the O₃-1 treatment did not. In the dominant microorganisms using carbon sources of carbohydrates and amino acids groups were significantly reduced by an elevated O₃ concentration in the rhizosphere soil. Our study shows that the elevated ozone levels may alter microbial community function in rhizosphere soil but not in the bulk soil. Hence, this suggests that O₃ effects on soil microbes are caused by O₃ detriments on the plant, but not by the O₃ direct effects on the soil microbes.

The objective of this study was to improve the ability to model the air quality impacts of biomass burning on the surrounding environment. The focus is on prescribed burning emissions from a military reservation, Fort Benning in Georgia, and their impact on local and regional air quality. The approach taken in this study is to utilize two new techniques recently developed: (1) adaptive grid modeling and (2) direct sensitivity analysis. An advanced air quality model was equipped with these techniques, and regional-scale air quality simulations were conducted. Grid adaptation reduces the grid sizes in areas that have rapid changes in concentration gradients; consequently, the results are much more accurate than those of traditional static grid models. Direct sensitivity analysis calculates the rate of change of concentrations with respect to emissions. The adaptive grid simulation estimated large variations in O₃ concentrations within 4 x 4-km² cells for which the static grid estimates a single average concentration. The differences between adaptive average and static grid values of O₃ sensitivities were more pronounced. The sensitivity of O₃ to fire is difficult to estimate using the brute-force method with coarse scale (4 x 4 km²) static grid models.

The effect of waterborne zinc on survival, growth, and feed intake of Indian major carp, Cirrhinus mrigala (Hamilton), advanced fry was studied under laboratory condition. Survival rates of C. mrigala advanced fry (2.71 ± 0.49 g) after 30 days exposure to control (0.01), 0.03, 0.06, 0.10, and 0.15 mg/L zinc using the static renewal method in freshwater at pH 7.3 ± 0.2, temperature 26 ± 2°C, and total hardness 114 ± 16 mg/L as CaCO₃ were 100%. Growth of the fish exposed to 0.10 and 0.15 mg/L of zinc was significantly lower (P < 0.05) than in control (0.01), 0.03, and 0.06 mg/L of zinc after 30 days of exposure. However, there were no significant differences (P > 0.05) in fish growth between 0.03 and 0.06 mg/L zinc concentrations. Feed intake rates were significantly (P < 0.05) reduced in the fish exposed to 0.10 mg/L and higher levels of zinc. The zinc accumulation in the whole body of the fish increased with increasing concentrations of the metal.

The aim of this survey was to assess metal concentrations in precipitation over the Aegean Sea and to identify possible source regions that contribute to their long-range transport to the northeastern Mediterranean. Total metal concentrations in 37 rainwater samples collected on the island of Lesvos showed a high variability depending mostly on the origin of the air masses influencing the rain events assessed by 4-day back trajectories. Concentrations of Al, Fe, Mn, Cu, Pb, Zn, Cr and Ni were rather similar to those found at other coastal sites in the Mediterranean basin, but Cd was significantly lower. The calculation of crustal enrichment factors of the metals along with the statistical analysis of the results showed that Saharan dust storms supply significant amounts of natural Al, Fe, Mn, Cr and Ni to the northern Aegean atmosphere, although some amounts of Cr and Ni are also contributed from anthropogenic sources. On the other hand, anthropogenic emissions largely determine Pb, Cu, Cd and Zn loads, although not all four metals follow the same enrichment and transportation pattern.

Impacts of heavy metal concentrations in sediments on the gastropod community structure were assessed in the coastal waters of Dumai, Sumatra, Indonesia. The objective of this study was to relate the levels of heavy metal pollution with the changes of gastropod community structure in the study area. Concentrations of Cd, Cu, Pb, Zn, Ni, and Fe in surface sediments collected from five sampling stations were analyzed and correlated with the abundance, species richness, and diversity of gastropod populations. Sediments at stations with more anthropogenic activities accumulated higher concentrations of heavy metals and consequently displayed lower abundances, lower species richness and diversity; while stations with lower heavy metal concentrations in sediments showed the opposite pattern in gastropod community metrics. The above findings are complemented by significant negative correlations p < 0.05-0.01) between concentrations of Cd, Cu, Pb, Zn, and Ni in the sediments and gastropod abundance and species richness. Among the metals analyzed, Cu and Zn had strongest negative correlations with the gastropod diversity which suggests that these metals may be the most detrimental to gastropod populations in the mangrove area of Dumai coastal waters.

Gaseous phosphine (PH₃) in the inshore atmosphere was observed from October 2005 to August 2006 at a coastal site of the Yellow Sea in China. The concentration of PH₃ ranged from 0.01 to 14.86 ng m⁻³ with an average of 1.14 ng m⁻³. The concentration showed a diurnal variation in PH₃ with the peak occurring at morning and the lowest point at noon. An obvious seasonal variation of atmospheric PH₃ was found, with the PH₃ levels in the summer higher than those in the winter. The PH₃ levels in the atmosphere were apparently affected by temperature, radiation, sources, and other meteorological factors. The data indicate that PH₃ can be transported between the terrestrial and inshore atmosphere of Qingdao and the Yellow Sea or the East China Sea in both directions. The study increases evidence that PH₃ participates within the global biogeochemical phosphorus cycle in P transport from land and inshore waters to the sea where commonly P is scarce and where PH₃ inflow could be of important.