Contribution Of Anthropogenic Sources Research Articles

Strontium isotope and major ion chemistry of the rainwaters from Guiyang, Guizhou Province, China

Twenty-two rainwater samples from Guiyang city, southwestern China, have been analyzed for their chemical compositions and 87Sr / 86Sr ratios, with a main purpose to get a better understanding of the general features of rainwater in Guiyang city and their correspondences to human activities. The rainwaters studied are almost acidic (pH = 4.53) and show big changes in major ion composition. Ca 2+ and Mg 2+ are the principal cations in the rainwaters and their mean values are 56.6 μmol/L (12.5–163.8 μmol/L) and 12.8 μmol/L (4.5–47.3 μmol/L ), respectively. The sum of Ca 2+ and Mg 2+ accounts for 78%–96% of the total cations in the studied rainwaters. Na + was the least abundant of the major cations with a mean content of 4 μmol/L (0.9–7.8 μmol/L). SO 4 2− is the predominant anion, with a mean content of 94 μmol/L (33.5–279.4 μmol/L), coming next is NO 3 − with a mean content of 48 μmol/L (2.1–251.8 μmol/L). SO 4 2− and NO 3 − together account for 77%–99% of the total anions. Ca 2+ and Mg 2+ in the rainwater are most likely from dissolution of carbonate minerals in dust or aerosol, unlike K + that shows more contribution of anthropogenic sources to the rainwater. Na + does not vary in concentration with Cl −. Significant enrichment of Cl − relative to Na + as compared with sea water indicates negligible contribution of marine source, which is supported by the evidence that the total rainwater samples show lower 87Sr / 86Sr ratios (ranging from 0.707934 to 0.709080) than sea water. The rainwater samples are characterized by high contents of NO 3 −, SO 4 2−, and Cl − relative to Na +, as compared to the rainwater from other areas in the world, suggesting that the anions (NO 3 −, SO 4 2−, and Cl −) have mainly of anthropogenic sources. Sr isotope shows potential to trace sources of contaminants when combined with other chemical factors: covariation of 87Sr / 86Sr ratio with Cl − / Na + in the rainwater suggest presence of at least two anthropogenic sources for the rainwater samples studied. The coal-combustion industries are probably the major atmospheric contaminant sources in Guiyang city.

Levels of selected metals in ambient air PM10 in an urban site of Zaragoza (Spain)

An assessment of the air quality of Zaragoza (Spain) was performed by determining the trace element content in airborne PM10 in a sampling campaign from July 2001 to July 2002. Samples were collected in a heavy traffic area with a high volume air sampler provided with a PM10 cutoff inlet. The levels of 16 elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were quantified after collecting the PM10 on Teflon-coated glass fiber filters (GFF). Regarding the PM10, 32% exceedance of the proposed PM10 daily limit was obtained, some of them corresponding to summer and autumn periods. The limit values of toxic trace elements from US-EPA, WHO, and EC were not exceeded, considering Zaragoza as a moderately polluted city under the current air quality guidelines. The contribution of anthropogenic sources to atmospheric elemental levels was reflected by the high values of enrichment factors for Zn, Pb, and Cu compared to the average crustal composition. Statistical analyses also determined the contribution of different sources to the PM10, finding that vehicle traffic and anthropogenic emissions related to combustion and industrial processes were the main pollutant sources as well as natural sources associated with transport of dust from Africa for specific dates. Regarding the influence of meteorological conditions on PM10 and trace elements concentrations, it was found that calm weather conditions with low wind speed favor the PM10 collection and the pollution for trace elements, suggesting the influence of local sources.

Distribution of trace metals in moss biomonitors and assessment of contamination sources in Portugal

A biomonitoring survey using the moss species [ Hypnum cupressiforme Hedw. and Scelopodium touretii (Brid.) L. Kock] was performed in the whole territory of Portugal, in order to evaluate the atmospheric deposition of the following elements: Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The concentrations of the same elements were also obtained in two types of soil samples, collected under the moss and in nearby plots without any plant coverage, and relationships between moss and soil concentrations was investigated using the multivariate statistical method of Co-inertia Analysis. Also, relationships between concentrations in moss and several anthropogenic, geologic, pedologic and environmental parameters were screened using the same method of Co-inertia Analysis. Higher concentrations of Cu, Pb and Zn were found in areas of higher population density, with higher gasoline consumption, while higher values of Fe and Cr occur in the driest region, with lower plant coverage, indicating strong contamination by resuspended soil particles. Results also show good agreement between moss and soil contents, even for elements with high contribution of anthropogenic sources. The spatial pattern in Portugal of element contents in mosses were also detected and discussed in relation to local contamination sources.

Nitrite in rain and dew in Santiago city, Chile. Its possible impact on the early morning start of the photochemical smog

Cations (pH, potassium, sodium, calcium, magnesium, and ammonium) and anions (sulfate, nitrate, nitrite, and chloride) concentrations were measured in Santiago city rain and dew waters collected during the 1995 to 1999. Concentrations measured in dews are considerably higher than those measured in rains. The high ionic concentration present in dew waters could contribute to their corrosion potential. Natural dust makes an important contribution to the ions present in dews, but the presence of rather high sulfate concentrations (up to 900 μeq/l) indicate a significant contribution of anthropogenic sources. A peculiar characteristic of dew waters is the relatively high nitrite concentrations (up to 180 μeq/l). This nitrite can be resuspended into the boundary layer after dew water evaporation, possibly due to the relatively high volatily of ammonium nitrite. This upward flux could constitute an important source of hydroxyl radicals in the early morning, contributing so to the initial steps of the observed photochemical smog.

Lead isotope ratio analysis by inductively coupled plasma sector field mass spectrometry (ICP-SMS) in soil digests of a depth profile

The application of inductively coupled plasma sector field mass spectrometry (ICP-SMS) (Finnigan-MAT, Element) to lead isotope ratio determination in soil samples is described. Discrimination of anthropogenic and geogenic lead sources requires both precise and accurate isotope ratio determination and also high versatility due to the complex matrix, which is typical for soil extracts. Moreover, a high sample throughput is required. ICP-SMS could therefore be implemented as the method of choice. Precision of isotope ratios of 206Pb/207Pb of better than 0.03% was obtained throughout the investigations in a concentration range of 5–50 ng g−1 in solution. Accuracy was illustrated by using the NIST SRM 981 isotopic ratio reference standard and was 0.03% for both the 207Pb/206Pb and 208Pb/207Pb ratios. In order to differentiate between anthropogenic and geogenic sources of lead in soils, both lead concentration and isotopic composition were determined by ICP-SMS along a soil profile collected from a Dystric Cambisol in Eastern Austria. Along the soil profile, a significant change of lead isotopic composition could be detected, showing the difference between anthropogenic (surface) and geogenic (parent rock) sources. Along with the total concentration of lead and other soil properties, the contribution of anthropogenic sources to the lead concentration of soils and their participation in lead mobilization can be estimated.

The influence of pulp and paper mill effluents on the composition of the humic fraction of aquatic organic matter

The humic fraction of dissolved organic matter was isolated from three sites of River Vouga (Portugal) and its lagoon, corresponding to unpolluted water and water contaminated with pulp mill effluent. Humic substances were characterized by elemental analysis, Fourier transform infrared spectroscopy, CPMAS- 13C-NMR spectroscopy and potentiometric titration. The fulvic acids isolated from the most contaminated site exhibit several structural features characteristic of lignosulphonic acids, such as a high sulphur content, the presence of sulphonic groups, higher phenol and methoxyl contents, higher aromaticity and lower carboxyl content than the fulvic acids upstream of the discharge from the pulp mill effluent. The humic substances further downstream still show some of those structural characteristics but they are preferentially shown in the humic acids than in the fulvic acids. These results highlight the importance of the contribution of anthropogenic sources of organic matter to the composition of humic substances from surface waters.

Guest Editorial: Global Warming and Population Health

Since the industrial revolution, the contribution of anthropogenic sources of greenhouse gases to the global environment has significantly increased. Greenhouse gases, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), are accumulating in the atmosphere. These trends are largely attributed to human activities, primarily fossil-fuel combustion, some industrial processes, for example cement production and mining, changes in land use, and agricultural practices. The International Panel on Climate Change (IPCC), made up of more than 2,500 of the world's leading scientists, has recently concluded that human activity might have already begun to change the global climate, and in the absence of efforts to reduce greenhouse gases, the concentrations of these gases are expected to increase significantly throughout the next century (IPCC, 1996).

A comparison between natural and anthropogenic emissions of the reduced sulfur compounds H2S, COS, and CS2 in a tropical industrialized region

Extensive ambient concentration and flux measurements have been performed in the heavily polluted region of Cubatao/Brazil. Substantial contribution of anthropogenic sources to the local reduced sulfur burden has been observed. As a result of this atmospheric sulfur burden average gas exchange between vegetated soils and the atmosphere shows net deposition. Based mainly on own field measurements a local budget for H2S, COS, and CS2 has been made up in order to calculate anthropogenic emissions. All major sources and sinks in the chosen atmospheric reservoir (24×20×1 km) have been taken into account. Due to the small reservoir size fluxes across its boundaries are dominant sources and sinks. The differences between outflux and influx therefore account for the unknown anthropogenic emissions which have been determined to be 80±10 (H2S), 66±15 (COS), and 29±6 Mmol year-1 (CS2). Other sources and sinks like natural emissions, chemical conversion, and dry deposition turned out to be of minor importance on a local scale. In fact, inside the investigated reservoir natural emissions were below 0.5% of anthropogenic emissions. Anthropogenic emissions of H2S, COS, and CS2 quantified in this work have been compared with global emission estimates for these compounds made by other authors. We conclude that global anthropogenic emissions of reduced sulfur compounds especially of COS and CS2 are currently under-estimated.

Atmospheric OCS: Evidence for a contribution of anthropogenic sources?

Carbonyl sulfide (OCS) in the boundary layer of the marine atmosphere was measured by gas chromatography with flame photometric detection on board ship following a meridional transect in the Atlantic Ocean between 37°S and 51°N. Overall, OCS levels from 174 individual samples averaged 537 ppt with a standard deviation of 104 ppt. A pronounced northward increase in OCS of, on the average, 26 ppt per 10° latitude was found, together with a mean interhemispheric ratio of 1.25 between OCS in northern and southern hemisphere air masses. OCS correlated significantly with CH4 and CO values obtained during the cruise by an independent investigator.

Source contribution of atmospheric aerosols in Japan by chemical mass balance method

Abstract The seasonal variation and regional features of source contributions to atmospheric particulates in Japan were investigated using a Chemical Mass Balance (CMB) method. The elemental concentrations of aerosol particles measured at the nine different National Air Surveillance Network from April 1977 to March 1985 were used in this study. Variations of estimated source contributions were also discussed for various analytical conditions regarding the types of release source and chemical species employed in the CMB analysis. When elements other than indicator elements of the assumed source types were added in the analysis by the CMB method, the contributions of some of source types were strongly affected. Soil source contribution was most significant among the five assumed sources at every site and was elevated in spring every year. On the other hand, the contributions of anthropogenic sources had peaks in early winter.

Trace metal transport in two tributaries of the Upper Chesapeake Bay: the Susquehanna and Bush Rivers

A study of Fe, Mn, Zn, and Cu transport in two tributaries of the Upper Chesapeake Bay (the Susquehanna and Bush Rivers) was performed. Sampling was conducted according to hydrologic seasons. Three phases [soluble (< 0.2 μm), fine (> 0.2 μm, < 3 μm) and coarse particulates (> 3 μm)] of each metal were separated by rapid filtration and then analyzed. Particulate Fe was the major Fe phase in both rivers during all seasons. Soluble Mn was the dominant Mn phase in winter in both rivers and also during fall and the snowmelt-runoff period in the Susquehanna River and summer at one Bush River station. Soluble Zn was the principal Zn phase in winter in both rivers and also in summer in the Susquehanna River, while particulate Zn was dominant during the remaining seasons. Copper showed the greatest prevalence in the soluble phase among the four metals studied. The soluble phase was the major form of Cu during fall, winter and spring in both rivers and also in summer in the Susquehanna River. The trace metal phase distributions were related to seasonal hydrologic conditions and water chemical phenomena, such as the release of Mn from anoxic sediments. The metal content of total suspended matter in the rivers was at least the same order of magnitude as seen for other world rivers, although the Fe and Mn contents in the total suspended matter were enriched above the world averages on some sampling dates in both the Susquehanna and Bush Rivers. The content of all four metals in the total suspended matter was greater than would be predicted based on the weathering of exposed suficial rock, indicating the contribution of anthropogenic sources to the total particulate metal content in both rivers.

Characterization of large particles at a rural site in the eastern United States: Mass distribution and individual particle analysis

A unique combination of an effective sampler and analysis of individual particles has been used in studying large particles (> 5 μm) at a rural site in eastern United States. The sampler is a modified ‘high volume’ rotary inertial impactor, which consists of four collectors of different widths, rotating at high speed and collecting particles by impaction. The collector surfaces were Mylar films coated with apiezon to ensure retention. After sampling, the collection surfaces were weighted to obtain the mass-size distribution. A section of the Mylar sample was transferred to a scanning electron microscope to study in detail the morphology and elemental content of individual particles. Results from two case studies indicated the following conclusions could be made: 1. (a) Natural sources, minerals and biologicals, were the main contributors to large particles (> 5 μm), 2. (b) Contribution of anthropogenic sources, mainly coal-fired power plants emitting fly ash particles, was limited to a few percent of the 5–10 μm size range, 3. (c) Pollen and some of the minerals were enriched in sulfur, probably as accumulation of sulfate on the particle surface, 4. (d) At low wind speeds the anthropogenic contribution was enhanced, whereas at high wind speeds natural sources were almost the only contributors to the large particle mode. In both cases the mass distribution of the large particles peaked at around 15 μm.