Semicontinuous PM2.5 sulfate and nitrate measurements at an urban and a rural location in New York: PMTACS-NY summer 2001 and 2002 campaigns

Several collocated semicontinuous instruments measuring particulate matter with particle sizes < or =2.5 microm (PM2.5) sulfate (SO4(2-)) and nitrate (NO3-) were intercompared during two intensive field campaigns as part of the PM2.5 Technology Assessment and Characterization Study. The summer 2001 urban campaign in Queens, NY, and the summer 2002 rural campaign in upstate New York (Whiteface Mountain) hosted an operation of an Aerosol Mass Spectrometer, Ambient Particulate Sulfate and Nitrate Monitors, a Continuous Ambient Sulfate Monitor, and a Particle-Into-Liquid Sampler with Ion Chromatographs (PILS-IC). These instruments provided near real-time particulate SO4(2-) and NO3- mass concentration data, allowing the study of particulate SO4(2-)/NO3- diurnal patterns and detection of short-term events. Typical particulate SO4(2-) concentrations were comparable at both sites (ranging from 0 to 20 microg/m3), while ambient urban particulate NO3- concentrations ranged from 0 to 11 microg/m3 and rural NO3- concentration was typically less than 1 microg/m3. Results of the intercomparisons of the semicontinuous measurements are presented, as are results of the comparisons between the semicontinuous and time-integrated filter-based measurements. The comparisons at both sites, in most cases, indicated similar performance characteristics. In addition, charge balance calculations, based on major soluble ionic components of atmospheric aerosol from the PILS-IC and the filter measurements, indicated slightly acidic aerosol at both locations.     

Toward a high-rate enhanced biological phosphorus removal process in a membrane-assisted bioreactor.

A membrane enhanced biological phosphorus removal (MEBPR) process was studied to determine the impact of hydraulic retention time (HRT) and solids retention time (SRT) on the removal of chemical oxygen demand (COD), nitrogen, and phosphorus from municipal wastewater. The MEBPR process was capable of delivering complete nitrification independent of the prevailing operating conditions, whereas a significant improvement in COD removal efficiency was observed at longer SRTs. In the absence of carbon-limiting conditions, the MEBPR process was able to achieve low phosphorus concentrations in the effluent at increasingly higher hydraulic loads, with the lowest HRT being 5 hours. The MEBPR process was also able to maintain optimal phosphorus removal when the SRT was increased from 12 to 20 days. However, at higher suspended solids concentrations, a substantial increase was observed in carbon utilization per unit mass of phosphorus removed from the influent. These results offer critical insights to the application of membrane technology for biological nutrient removal systems.     

Elemental carbon and sulfate aerosols over a rural mountain site in the northeastern United States: Regional emissions and implications for climate change

The effect of elemental carbon (EC) on global as well as regional climate forcing is potentially very important. However, the EC data for northeastern U.S. is sparse. Daily EC concentrations, [EC], and [SO₄] were measured in the northeastern U.S. at a regionally representative rural site, Whiteface Mountain (WFM; 44.366°N, 73.903°W, 1.5 km amsl, above mean sea level), New York (NY), for 1997. The air mass origin was determined using 6-h backward in time air trajectories obtained from the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT 4). [EC] and [SO₄] were highly variable and influenced by synoptic–scale meteorology (rainy vs dry periods). The maximum daily [EC] and [SO₄] were 364 ± 55 and 28,800 ± 3000 ng m^?3, respectively. [EC] and [SO₄] also showed seasonal variations at WFM. Occurrences of high daily [EC] were mainly in spring months, while peak daily [SO₄] concentrations occurred in summer months. This behavior of aerosols is due to the fact that the sources of EC and SO₄ are not the same and also due to the enhanced photochemical activity during summer months that increased the production of SO₄ from SO₂. High [EC] and [SO₄] values were associated with westerly air flow from the industrialized Midwestern U.S. Sector analysis using HYSPLIT 4 air trajectories showed that regions lying between the southwest and northwest of the WFM contributed 81% and 83% of the [EC] and [SO₄], respectively. The monthly net direct radiative forcing for shortwave (SW) due to EC and SO₄ aerosols at the top of the atmosphere (TOA) varied from ?0.05 to ?0.50 W m^?2, with an annual average of ?0.20 ± 0.15 W m^?2 that gives a net cooling effect. Average net radiative forcing at WFM for clear sky is lower than the global average radiative forcing reported by IPCC (Foster and Ramaswamy, 2007).     

Potential applications of immobilized bitter gourd (Momordica charantia) peroxidase in the removal of phenols from polluted water

The potential applications of immobilized bitter gourd peroxidase in the treatment of model wastewater contaminated with phenols have been investigated. The synthetic water was treated with soluble and immobilized enzyme preparations under various experimental conditions. Maximum removal of phenols was found in the buffers of pH values 5.0-6.0 and at 40 degrees C in the presence of 0.75 mM H(2)O(2). Fourteen different phenols were independently treated with soluble and immobilized bitter gourd peroxidase in the buffer of pH 5.6 at 37 degrees C. Chlorinated phenols and native phenol were significantly removed while other substituted phenols were marginally removed by the treatment. Phloroglucinol and pyrogallol were recalcitrant to the action of bitter gourd peroxidase. Immobilized bitter gourd peroxidase preparation was capable of removing remarkably high percentage of phenols from the phenolic mixtures. Significantly higher level of total organic carbon was removed from the model wastewater containing individual phenol or complex mixture of phenols by immobilized bitter gourd peroxidase as compared to the soluble enzyme. 2,4-dichlorophenol and a phenolic mixture were also treated in a stirred batch reactor with fixed quantity of enzyme for longer duration. The soluble bitter gourd peroxidase ceased to function after 3h while the immobilized enzyme was active even after 6h of incubation with phenolic solutions.     

Fuzzy rule-based modelling for human health risk from naturally occurring radioactive materials in produced water

Produced water, discharged from offshore oil and gas operations, contains chemicals from formation water, condensed water, and any chemical added down hole or during the oil/water separation process. Although, most of the contaminants fall below the detection limits within a short distance from the discharge port, a few of the remaining contaminants including naturally occurring radioactive materials (NORM) are of concern due to their bioavailability in the media and bioaccumulation characteristics in finfish and shellfish species used for human consumption. In the past, several initiatives have been taken to model human health risk from NORM in produced water. The parameters of the available risk assessment models are imprecise and sparse in nature. In this study, a fuzzy possibilistic evaluation using fuzzy rule based modeling has been presented. Being conservative in nature, the possibilistic approach considers possible input parameter values; thus provides better environmental prediction than the Monte Carlo (MC) calculation. The uncertainties of the input parameters were captured with fuzzy triangular membership functions (TFNs). Fuzzy if-then rules were applied for input concentrations of two isotopes of radium, namely (226)Ra, and (228)Ra, available in produced water and bulk dilution to evaluate the radium concentration in fish tissue used for human consumption. The bulk dilution was predicted using four input parameters: produced water discharge rate, ambient seawater velocity, depth of discharge port and density gradient. The evaluated cancer risk shows compliance with the regulatory guidelines; thus minimum risk to human health is expected from NORM components in produced water.     

Solid Waste Management Practices in the Eastern Province of Saudi Arabia

Solid waste management practices in the Eastern Province of Saudi Arabia are reviewed. The officials of various municipalities and agencies responsible for collecting and disposing of municipal waste were interviewed. The refuse generation rate found is in the range of 1.61–2.72 kg per capita per day. The refuse composition data indicate a high percentage of glass, metals, and wood. For storage purposes, 0.2-m³ barrels are used in residential areas and 0.75 to 1.50 m³-capacity containers are used in commerical areas. The present solid-waste collection system is labor-intensive, and a significant part of the budget is spent on collection and haul operations. The unit collection and haul cost is much higher than the unit disposal cost of refuse. The direct haul of refuse is the common practice, and the use of transfer stations has not yet been considered. It is also observed that the disposal methods used at these sites are not in line with modern techniques for refuse disposal. Landfilling and combined burning and landfilling are the common disposal methods at all the sites.     

Spatio-temporal variations in water quality of Nullah Aik-tributary of the river Chenab, Pakistan

This study reports the spatio-temporal changes in water quality of Nullah Aik, tributary of the Chenab River, Pakistan. Stream water samples were collected at seven sampling sites on seasonal basis from September 2004 to April 2006 and were analyzed for 24 water quality parameters. Most significant parameters which contributed in spatio-temporal variations were assessed by statistical techniques such as Hierarchical Agglomerative Cluster Analysis (HACA), Factor Analysis/Principal Components Analysis (FA/PCA), and Discriminant Function Analysis (DFA). HACA identified three different classes of sites: Relatively Unimpaired, Impaired and Less Impaired Regions on the basis of similarity among different physicochemical characteristics and pollutant level between the sampling sites. DFA produced the best results for identification of main variables for temporal and spatial analysis and separated eight parameters (DO, hardness, sulphides, K, Fe, Pb, Cr and Zn) that accounted 89.7% of total variations of spatial analysis. Temporal analysis using DFA separated six parameters (E.C., TDS, salinity, hardness, chlorides and Pb) that showed more than 84.6% of total temporal variation. FA/PCA identified six significant factors (sources) which were responsible for major variations in water quality dataset of Nullah Aik. The results signify that parameters identified by statistical analyses were responsible for water quality change and suggest the possibility of industrial, municipal and agricultural runoff, parent rock material contamination. The results suggest dire need for proper management measures to restore the water quality of this tributary for a healthy and promising aquatic ecosystem and also highlights its importance for objective ecological policy and decision making process.     

Oxidation of SO2 in Clouds at Whiteface Mountain

In-cloud oxidation of SO₂ byH₂O₂ was investigated using a tracertechnique based on SO^2– ₄/Se ratios atWhiteface Mountain, New York during summer months from1990 to 1998. Cloud water samples collected at themountain's summit (1.5 km above mean sea level) andaerosols at a below cloud site (Lodge) located at 0.6km amsl and in cloud interstitial air at the summitwere analyzed for SO^2– ₄ and selectedtrace elements. Gaseous SO₂ andH₂O₂were measured in realtime. Cloud water pH wasgenerally below 5.0 with a mean value of 3.6. Theresults show that significant in cloud oxidation occursin clouds during summer months varying from belowdetection to 62% with on average approximately 24% ofthe cloud water SO^2– ₄ produced from in-situ SO₂ oxidation. During summer the clouds wereoxidant limited for approximately one third of thetime.     

Fluoride contamination in groundwater of central Rajasthan,India and its toxicity in rural habitants

This study was carried out to assess fluoride (Fl) concentration in groundwater in some villages of central Rajasthan, India, where groundwater is the main source of drinking water. Water samples collected from deep aquifer-based hand pumps were analyzed for Fl content. Fluoride in groundwater of 121 habitations of Bhilwara tehsil of Bhilwara district of Rajasthan was determined to examine the potential Fl-induced toxicity in rural locations. Fluoride concentrations in the tehsil ranged from 0.5 to 5.8 mg/l. In the tehsil, 69 villages (57%) were found to have Fl concentration beyond the maximum desirable limit recommended in Bureau of Indian Standards (BIS), 10500, 1991. Fifty-eight percent population of these villages was under the threat of fluorosis. One percent population of tehsil living in two villages ingested more than 5 mg/l Fl in each liter of drinking water and at maximal risk for dental and skeletal fluorosis. 142 individuals of these villages were examined for fluorosis. Data indicated that only four individuals (2.82%) did not exhibit dental fluorosis. Most individuals were found to suffer from mild (34.51% or 49 individuals) and moderate (31.69% or 45 individuals) fluorosis. Severe dental fluorosis was recorded in only 16 individuals (11.27%). In 104 individuals above 21 years of age examined for the prevalence of skeletal fluorosis, 66 were positive for skeletal fluorosis with a maximum 36.5% with grade I skeletal fluorosis. Grade II skeletal fluorosis was recorded in 28 individuals (26.9%). Data in this study demonstrate that there is a need to take ameliorative steps in this region to prevent fluorosis.     

Indoor exposure to respirable particulate matter and particulate-phase PAHs in rural homes in North India

In order to evaluate the exposure of the northern India rural population to polyaromatic hydrocarbon (PAH) inhalation, indoor pollution was assessed by collecting and analyzing the respirable particulate matter PM_2.5 and PM₁₀ in several homes of the village Bhithauli near Lucknow, UP. The home selection was determined by a survey. Given the nature of biomass used for cooking, homes were divided into two groups, one using all kinds of biomass and the second type using plant materials only. Indoor mean concentrations of PM_2.5 and associated PAHs during cooking ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to 12.43 ± 1.15 μg/m³, respectively. Similarly, PM₁₀ and total PAHs were in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m³, respectively. The pollutant levels during cooking were significantly higher compared to the noncooking period. The study confirmed that indoor pollution depends on the kind of biomass fuel used for cooking.