INVESTIGATION OF SULFUR COMPOUNDS IN SELECTED STAGNANT WATER BODIES

Sulfur compounds, primarily in the form of sulfides (S2.), sulfites (50)'") andsulfates (50t) have been neglected but has a strong effect upon water quality.The dark colour sediments and strong unpleasant ordours often indicate the 52.contamination in aquatic bodies. To the best of our knowledge, no attempt hasbeen made to investigate these compounds and to asses their contribution to thedegradation of water quality. Both the bacteria and dissolved oxygen (DO) areplaying leading roles in determining the fate of 5 containing compounds inaquatic systems.In this investigation it was intended to study the possible relationships betweensulfur species and DO. Four urban stagnant water bodies effected by impropersewage disposal, industrial waste, wet and dry deposition of atmospheric 50/'were investigated along with a prawn farm and two coconut husk soaking pitsinherited with S compounds. These water bodies indicated the emission ofvolatile 5 compounds. These water bodies indicated the emission of volatile 5compounds From their characteristic rotten egg smell.Under this study 52., SO)·2 and 50t levels were monitored along with DO, pHand temperature to investigate the possible correlation method introduced byPawlak and Pawlak (1999) was employed in determination of 52. levels while allother parameters were measured by employing standard methods.Based on the results obtained, only S2. shows a significant correlation with DOunder ambient conditions. Finally, measured dissolved 52. levels were utilized todetermine the possible H25 emission levels. Calculations have shown that each ofthe water body is emitting gaseous H25 and in most cases, emission levels aregreater than the ordour thresholds accounting for the unpleasant smell near thesestagnant water bodies.*Correspondence author

Emission factors for selected PAHs and carbonyl compounds from locally available mosquito coils and joss stick brands

In recent years, numerous investigations have revealed that indoor air pollution has a subtle chemistrywhich produces a range of pollutants. Combustion sources (some of which can be eradicated fromindoors) have become the major contributor to the indoor air pollution and the pollutants emanatingfrom these sources can poses serious health threats. Two of the combustion sources which can beeliminated from indoor settings, burning mosquito coils and joss sticks, were investigated in this studywith the emphasis on the einissions of the carbonyl compounds and polycyclic aromatic hydrocarbons[PAHs].Both carbonyl compounds and PAHs are known health hazards which are ubiquitous in the indoorsdue to incomplete combustion of organic compounds as well as due to the off gassing from consumerproducts. Poor air circulations entrap the pollutants indoors elevating the exposure and hence thehealth risks. Seven mosquito coil brands (locally made) and eight joss stick brands (both locally andIndian made) were burned in a laboratory setting simulating the indoor conditions. All the smokeemanating from the combustion source was passed through a prototype sampler. The volatile carbonylcompounds were derivatized to non-volatile 2,4-dinitrophenyl hydrazones and PAHs were collectedseparately using methanol. The hydrazone derivatives of the carbonyl compounds and the PAHswere separated individually using reversed-phase HPLC and quantified using UV and fluorescencedetectors respectively.The average emission factors for mosquito coils were 266 ± 114 ug g' (formaldehyde), 94 ± 37 ug gI (acetaldehyde) and 67 ± 13 ug g' (acetone) compared to that of joss sticks 127 ±'18 ug g'(formaldehyde), 38 ± 11 ug g' (acetaldehyde) and 38 ± 11 ug s:' (acetone). The levels of acrolein,croton aldehyde and propanaldehyde were very low and they could not be quantified with significantaccuracy and precision.The emission factors for naphthalene, acenapthene, acenapthylene, fluorine, phenanthrene, anthracene,fluoranthene, pyrene, benzo[ a]anthracene, chrysene, benzo[b ]fluoranthene, benzo[k ]fluoranthene andbenzo[a]pyrene were 6.33 ± 1.00,9.45 ± 1.04, 2.44 ± 0.47,6.54 ± 0.54,9.07 ± 0.55,3.96 ± 0.98,4.63± 0.44, 0.64 ± 0.17, 1.52 ± 0.42,2.67 ±0.66, 0.25 ± 0.08, 0.21 ± 0.05 and 0.17 ± 0.15 ug g' respectivelyfor mosquito coils and the emission factors of joss sticks for the same compounds were 5.33 ± 0.94,7.80 ± 0.95, 2.14 ± 1.14,4.25 ± 1.04,4.79 ± 0.66,3.53 ± 0.42,5.04 ± 0.99, 0.44 ± 0.12, 1.14 ± 0.17,1.63 ± 0.63, 0.1 R :: 0.04, 0.23 ± 0.15 and 0.15 ±.06 /lg g-I respectively.In general, Indian joss stick brands emitted more PAHs and carbonyl compounds compared to thelocal brands. This research is an attempt to glance at the exposures which can be prevented throughsimple measures such as control Iing the indoor combustions.

DEVELOPMENT OF AN ENVIRONMENT FRIENDLY METHOD TO REMOVE THE COLORED COMPONENTS FROM INDUSTURIAL WASTE WATER

Nowadays, synthetic dye context is a vital component in the textile and dyeing industries.The garr ient factories in the free trade zone that are discharging dyes and other colouredcornpounds into waterways pollute the environment. In this project, attempts were made todesign an environment friendly methodology to degrade Azo dyes by means of Eco--efficient techniques. Optimum conditions were evaluated for the redox-degradation of theAzo dyes and some of the dyes that are used in garment industry. The fidelity of theproposed mechanism was confirmed by the spectroscopic and GC analyses. As a reducingagent, metallic iron has fulfilled all the requirements that are prescribed for green chemicalconcepts.The results presented in this report clearly demonstrate that Anthroquinone-2-sulphonicacid is a powerful catalyst, capable of accelerating the reaction rate by orders ofmagnitude. The powdered form of charcoal amalgamated with metallic iron hasfacilitated as a better substrate to adsorb the dye component improving the contacts ofreactant molecules with the catalyst and dye molecules. The experimental results revealedthat pH 4 is the optimum condition for the redox degradation of the dye, which isconfirmed by electrochemical, and thermodynamic calculations. The elevation of thereaction temperature has accelerated the reaction by several orders of magnitude. Todemonstrate the applications in real world a continuous flow reduction apparatus wasdesigned and constructed.

CONSTRUCTION OF A LOW COST AIR SAMPLER AND IT'S APPLICATION IN SAMPLING VOLATILE CARBONYL COMPOUNDS

lntcrcxt is expanding in measuring. concentrations of volatile organic compounds inbuildings since it is rccogniscd that many peoples' exposure to these compounds occur inthe indoor environment. However. such data are not available in Sri Lanka primarily dueto lack 01"proper equipment for quantitation and their high maintenance cost. This paperdcxcribcx the construction of a low cost air sampler (Rs. 40()/=) using commonly availablematerials.The air sampler contains a muffler fan to pull .unhient air though a filrcrts) and/or a bed ofsorhcnt material. which are housed in a variable length pye tube. Battery poweredmuffler fan and lightweight are two of the convenient features of this air sampler thatminimisc operational and transportation difficulties to the user.Vularilc carbonyl compounds such as formaldehyde acetaldehyde and acetone arecommonly found in indoors ambient air due to the combustion sources and emissions fromsvnthcric household products. Since formaldehyde is a known carcinogen andacetaldehyde is a suspected carcinogen compound. they were selected as the modelcompounds for the evaluation of constructed sampler. A filter paper spiked with 2. 4-dinitrophcnylhydruzcnc is used to collect the airborne carbonyl compounds at a flow rate ofI.X Cill'/SCC. Filters were sonicated in methanol and extracts were separated using a C,xcolumn for qu.uuitation at lSO mm wavelength. Quanutaiion limits estimates thats.unpling of I () dm ' ambient air enables minimum quantitauon of O.S formaldehyde. 1.0acetaldehyde and 1.2 acetone accurately. The paper also reports quantified levels ofairborne carbonyls from different indoor environments.

Toxic Volatile Organic Compounds in Environmental Tobacco Smoke:Emission Factors for Modeling Exposures of California Populations

The primary objective of this study was to measure emission factors for selected toxic air in environmental tobacco smoke (ETS) using a room-sized environmental chamber. The emissions of 23 volatile organic compounds (VOCs), including 1,3-butadiene, three aldehydes and two vapor-phase N-nitrosarnines were determined for six commercial brands of cigarettes and reference cigarette 1R4F. The commercial brands were selected to represent 62.5% of the cigarettes smoked in California. For each brand, three cigarettes were machine smoked in the chamber. The experiments were conducted over four hours to investigate the effects of aging. Emission factors of the target compounds were also determined for sidestream smoke (SS). For almost all target compounds, the ETS emission factors were significantly higher than the corresponding SS values probably due to less favorable combustion conditions and wall losses in the SS apparatus. Where valid comparisons could be made, the ETS emission factors were generally in good agreement with the literature. Therefore, the ETS emission factors, rather than the SS values, are recommended for use in models to estimate population exposures from this source. The variabilities in the emission factors (pgkigarette) of the selected toxic air contaminants among brands, expressed as coefficients of variation, were 16 to 29%. Therefore, emissions among brands were generally similar. Differences among brands were related to the smoked lengths of the cigarettes and the masses of consumed tobacco. Mentholation and whether a cigarette was classified as light or regular did not significantly affect emissions. Aging was determined not to be a significant factor for the target compounds. There were, however, deposition losses of the less volatile compounds to chamber surfaces

Contribution of dissolved sulfates and sulfites in hydrogen sulfide emission from stagnant water bodies in Sri Lanka

Abstract Accumulation of sulfur-containing compounds and their bacterial mediated reductions have led to the emission of pungent odors from stagnant water bodies. This study is focused on the contribution of inorganic sulfur compounds in the emission of hydrogen sulfide. The measured dissolved oxygen levels have demonstrated good negative correlations with the dissolved sulfide levels implying the oxygen deficiency is the key for the reduction of sulfate ion and sulfite ion to sulfide ion. Particularly, the dissolved molar fractions of sulfide from the total dissolved sulfur compounds (sulfates, sulfites and sulfides) have a very good correlation with the dissolved oxygen for the stagnant water bodies except the artificially aerated prawn farms. For the stagnant water bodies with significant correlations, linear regressions are reported for them to be utilized in estimating one component of the regression from the measurement of the other. The measured data were further utilized to estimate the levels of hydrogen sulfide gas. The pH of the water bodies has confined much of the dissolved sulfides in the form of bisulfide ion and they can be easily escaped to the atmosphere upon acidification due to industrial discharges and/or acidic precipitations. The estimated levels of hydrogen sulfide just above the water surface were plotted for the most polluted stagnant water body in Sri Lanka for the pH range of 5-10 and temperature range of 25-35°C

What do We Know the Snow Darkening Effect Over Himalayan Glaciers?

The atmospheric absorbing aerosols such as dust, black carbon (BC), organic carbon (OC) are now well known warming factors in the atmosphere. However, when these aerosols deposit onto the snow surface, it causes darkening of snow and thereby absorbing more energy at the snow surface leading to the accelerated melting of snow. If this happens over Himalayan glacier surface, the glacier meltings are expected and may contribute the mass balance changes though the mass balance itself is more complicated issue. Glacier has mainly two parts: ablation and accumulation zones. Those are separated by the Equilibrium Line Altitude (ELA). Above and below ELA, snow accumulation and melting are dominant, respectively. The change of ELA will influence the glacier disappearance in future. In the Himalayan region, many glacier are debris covered glacier at the terminus (i.e., in the ablation zone). Debris is pieces of rock from local land and the debris covered parts are probably not affected by any deposition of the absorbing aerosols because the snow surface is already covered by debris (the debris covered parts have different mechanism of melting). Hence, the contribution of the snow darkening effect is considered to be most important "over non debris covered part" of the Himalayan glacier (i.e., over the snow or ice surface area). To discuss the whole glacier retreat, mass balance of each glacier is most important including the discussion on glacier flow, vertical compaction of glacier, melting amount, etc. The contribution of the snow darkening is mostly associated with "the snow/ice surface melting". Note that the surface melting itself is not always directly related to glacier retreats because sometimes melt water refreezes inside of the glacier. We should discuss glacier retreats in terms of not only the snow darkening but also other contributions to the mass balance

Investigation of trace metals in air particulate matter collected from Colombo

The suspended particulate matter (SPM) in air is a complex multi-phase mixture of all airborne chemicals.Among the airborne inorganic chemicals, compounds associated with heavy metals have subjected tonumerous chemical investigations due their known health effects. Uniqueness of the heavy metalshas attributed its use in identifying or tracing the pollutant sources through source apportionmentstudies and in understanding the distribution of pollutants through computer modeling.In general, airborne metals exist in trace quantities. The suspended particulate matter may contain themetallic species as fine particles or they may have adsorbed onto other particulate matter originatedfrom natural or human activities. Agglomerated heavier particle settles due to gravitation and pose alesser risk to human health. Finer particles with aerodynamic diameter less than 2.5 urn (PM2) arebelieved to posses the biggest health threat through respirationCentral Environmental Authority (CEA) has been involved in air quality monitoring at the ColomboFort Railway Station. Using their high volume air sampler, particles having aerodynamic diameter lessthan I0 ~L1n(PM 10) were collected onto glass fiber filters daily during the period of November 2003 toNovember 2005 November. They were gravimetrically analyzed by CEA. This study was focused tofurther investigate randomly selected filters (two filters per month) to differentiate the levels of selectedmetals during the period. The filters were acid digested to recover the airborne metallic species.Levels of copper (Cu), nickel (Ni), cadmium (Cd), lead (Pb) and manganese (Mn) were analyzed byusing atom ic absorption spectrophotometer at the Department of Chemistry, University of ColomboThe average concentrations found during the study were Cu = 0.29 ± 0.25 ng/rri', N i = 0.21 ± 0.1 0 ng/m', Pb = 0.59 ± 0.48 ng/rn", Cd = 0.03 ± 0.03 ng/rn ', Mn = 0.43 ± 0.22 ng/rn '. During the study periodPb levels were found to be the highest and Cd levels were found to be the lowest. The maximumairborne levels were 1.24 ng/rn ' for ClI in April 2005,0.56 ng/rn ' for Ni in January 2005,2.37 ng/m 'for Pb in February 2004, 0.09 ng/m ' for Cd in February 2004 and 0.78 ng/rn ' for Ni in May 2005.On average the minimum airborne levels were found in the period of May to August. This is attributedto the settling of particles with rainfall as well as the wind patterns which drifts the pollutants awayfrom the sampler during the season. From November to Apri I all the five metals have showed relati velyhigher concentrations compared to any other months in each year. This may be due to poor dispersionpatterns in the Colombo air which results in stagnating pollutants. In general, wind speed is relativelyhigher for the period of May to August compared to the period of November to AprilThe most prevailing metal in the Colombo air is Pb while the least prevailing metal is Cd. The levelsofPb have demonstrated a pronounced decline in concentration starting from April 2005 whrch coincideswith the introductiorr of un-leaded petrol to Sri Lankan market in January 2004.

Use of Volatile Tracers to Determine the Contribution ofEnvironment Tobacco Smoke to Concentrations of Volatile Organic Compoundsin Smoking Environments

Three volatile nitrogen-containing compounds, 3-ethenylpyridine (3-EP), pyridine and pyrrole, were investigated as potential tracers for determining the contribution of environmental tobacco smoke (ETS) to concentrations of volatile organic compounds (VOCs) in indoor environments with smoking. The source emission rates of the three tracers and ten selected VOCs in ETS were first measured in a room-size environmental chamber for a market-weighted selection of six commercial cigarettes. The ratios of the emission rates of the tracers to the emission rates of the selected VOCs were calculated and compared among the six brands. The utility of the tracers was then evaluated in a field study conducted in five office buildings. Samples for VOCs were collected in designated smoking areas and adjoining non-smoking areas, air change rates were measured, and smoking rates were documented. Concentrations of the three tracers in the smoking areas were calculated using a mass-balance model and compared to their measured concentrations. Based on this comparison, 3-EP was selected as the most suitable tracer for the volatile components of ETS, although pyrrole is also potentially useful. Using 3-EP as the tracer, the contributions of ETS to the measured concentrations of the selected VOCs in the smoking areas were estimated by apportionment. ETS was estimated to contribute 57 to 84 percent (4.1 to 26 pg m{sup -3}) of the formaldehyde concentrations, 44 to 69 percent (0.9 to 5.8 pg m{sup -3}) of the 2-butanone concentrations, 37 to 58 percent (1.3 to 8.2 pg m{sup -3}) of the benzene concentrations, and 20 to 69 percent (0.5 to 3.0 pg m{sup -3}) of the styrene concentrations. The fractional contributions of ETS to the concentrations of acetone, toluene, ethylbenzene, xylene isomers and d-limonene were all less than 50 percent

PEAT-CLSM : A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model

Peatlands are poorly represented in global Earth system modeling frameworks. Here we add a peatland-specific land surface hydrology module (PEAT-CLSM) to the Catchment Land Surface Model (CLSM) of the NASA Goddard Earth Observing System (GEOS) framework. The amended TOPMODEL approach of the original CLSM that uses topography characteristics to model catchment processes is discarded, and a peatland-specific model concept is realized in its place. To facilitate its utilization in operational GEOS efforts, PEAT-CLSM uses the basic structure of CLSM and the same global input data. Parameters used in PEAT-CLSM are based on literature data. A suite of CLSM and PEAT-CLSM simulations for peatland areas between 40 degrees N and 75 degrees N is presented and evaluated against a newly compiled data set of groundwater table depth and eddy covariance observations of latent and sensible heat fluxes in natural and seminatural peatlands. CLSM's simulated groundwater tables are too deep and variable, whereas PEAT-CLSM simulates a mean groundwater table depth of -0.20 m (snow-free unfrozen period) with moderate temporal fluctuations (standard deviation of 0.10 m), in significantly better agreement with in situ observations. Relative to an operational CLSM version that simply includes peat as a soil class, the temporal correlation coefficient is increased on average by 0.16 and reaches 0.64 for bogs and 0.66 for fens when driven with global atmospheric forcing data. In PEAT-CLSM, runoff is increased on average by 38% and evapotranspiration is reduced by 19%. The evapotranspiration reduction constitutes a significant improvement relative to eddy covariance measurements.Peer reviewe