Differences in the rainwater composition on two consecutive days

The relationship between the rainwater composition on two consecutive rain days was analyzed. Logrono, a remote station in the North of Spain was chosen for the analyses. The concentration of the major ions in the rainwater of the first rain day is linearly related to the concentration of the second rain day except for those ions whose source is the soil (Ca²⁺ and Mg²⁺). These ions are related to SO₄ ^2? and NO₃ ^? in the first rain day, but not in the second.     

Organic composition in the dry season rainwater of Guangzhou, China

This paper reports the results from a study of the organic composition of rainwater collected at Tianhe district of Guangzhou city, P.R. China, during the dry season. Several special setups of a pyrex bottle with a glass funnel were used for the collection of the rainwater. Three fractions (aliphatics, PAHs and fatty acids) were separated from the total extracted organic compounds and identified with GC-MS. The molecular diagnostic ratios were utilized for the source reconciliation. The aliphatic hydrocarbon and the biomarkers (triterpanes and steranes) distribution show a characteristic of the petrochemical source in the rainwater samples. The PAHs diagnostic ratios [e.g. MP/P, MPI, Fl/ (Fl + Py)] indicated vehicular emissions. The fatty acids ratios (e.g. C_18:1/C_18:0 and C_18:2/C_18:0) reflect the contribution of cooking emissions, while the higher plant waxes play little part. Moreover, the values of MP/P, MPI, BaA/(BaA + CT) and BeP/(BeP + BaP) reflected the origin of the long-distance transportation to some extent. On the whole, for the dry season rainwater, all molecular diagnostic ratios indicated the complexity of the organic composition of the rain, which have the characteristics of both a local emission contribution and a long-distance transportation contribution.     

Use of environmental isotopes and hydrochemistry as indicators for the origin of groundwater resources in El Dabaa area,northwestern coastal zone of Egypt

The EI-Dabaa area is located on the northwestern coastal zone of Egypt and is considered to be one of the most important regions for land reclamation and agriculture. In addition, it has been selected as a potential site for constructing Egypt's first nuclear power plant.In April 1989, 14 groundwater samples were collected from the area as well as collecting samples from the Mediterranean sea and from local rainwater. These samples were subjected to chemical and environmental isotope analyses. The results of the analyses for stable isotopes (oxygen-18 and deuterium) indicate that the main recharge source of the groundwater in El-Dabaa is the local precipitation during the rainy season. Variation of the environmental tritium content as well as in the chemical composition of both major cations (Na,K,Ca,Mg) and major anions (Cl,SO₄,HCO₃) between different groundwaters in the studied area reflect the high degree of inhomogeneity of the aquifer and different recharging conditions due to permeability of the water bearing formation.The chemical water type of the El-Dabaa groundwater is sodium sulphate (Na₂SO₄) and the SAR values illustrate the suitability of these groundwaters for agricultural purposes.     

Wet deposition chemistry studies at Suva, Fiji, a remote tropical island site in the south Pacific

A field project encompassing wet-only rainwater sampling was initiated as a bilateral Fiji/Australia activity. Normally, biweekly samples were collected, using a wet-only rainwater sampler, and analysed for H⁺, Na⁺, K⁺, Mg²⁺, NH₄ ⁺, Cl^–, NO₃ ^–, SO₄ ^2–, PO₄ ^3-, methane sulphonic acid, oxalic acid, formic acid and acetic acid. The pH of the rainwater ranged between 5.730 and 4.480 with an average value of 5.176, slightly lower than the pH of unpolluted rainwater saturated with atmospheric CO₂(pH = 5.650). Na⁺and Cl^–were the major ions with average concentrations of 98.15 M and 109.57 M respectively. There is an excellent correlation between the cation sum (average 147.71 eq L^-1) and the anion sum (average 142.12 eq L^-1) attesting to the quality of the data generated. This paper presents the detailed results of the study for a relatively clean remote island site in Suva, Fiji, latitude 18° 09 S, longitude 178° 27 E, height 6 m, and outlines prospects for further work.     

Stabilitätsverhalten von ausgewählten anorganischen Spurenstoffen in Niederschlagsproben

The stability of H⁺, NH ₄ ⁺ , and PO ₄ ^3? ions in rainwater samples was in vestigated under different conditions cf storage and transport. Microbiological and physicochemical processes account for changes. Suppression of microbiological activities in deposition networks using conventional analyses may be achieved by adding AgCl-powder and by cooling to +4 °C.     

Airborne fine particulate matter (PM2.5) at industrial,high- and low-density residential sites in a Nigerian megacity

Abstract

Airborne particulate matter PM_2.5 was collected in an industrial, a low-density, and a high-density residential area of Lagos from December 2010 to November 2011, and elemental composition was determined by proton-induced X-ray emission. Across the months, mass concentrations ranged from 13 to 237?µg?m^?3, exceeding the World Health Organization guideline value of 10?µg?m^?3. Data on 24 elements were obtained, with maximum values during Harmattan season months; source identification and apportionment studies by positive matrix factorization suggested that petroleum oil combustion (70%) was the major source of PM_2.5 and could pose a great hazard to Lagos receptors.     

Sensitivity of Ozone Production to the Nmhc Composition,Aerosol Back-Scattering and High Chimney Emission

Abstract

In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NO _x emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10^?9 cm³ s^?1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition.

Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.

In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NO _x from high chimneys cannot be ignored. in this study, NO _x is assumed to be emitted in the layer between 235–460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NO _x emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated.     

The atmospheric degradation and impact of perchloroethylene

The present paper reviews the existing literature on the atmospheric degradation and impact of perchloro‐ethylene (PER). Topics covered are: assessment of the relative importance of primary reactions of PER with OH, Cl, O₃ and other reactive species; other tropospheric sinks for PER; estimated tropospheric lifetime, observed concentrations and atmospheric budget calculations; breakdown mechanisms leading to the formation of phosgene, and possibly trichloroacetyl chloride and carbon tetrachloride; contribution of PER to atmospheric chlorine loading; impact of PER on tropospheric ozone formation; uptake and hydrolysis of degradation products by clouds, rainwater and the oceans; contribution of PER to chloride and acidity in rainwater; potential contribution of PER to trichloroacetic acid in the hydrosphere, soil and the biosphere.     

Origin and Distribution of Suspended Organic Matter As Inferred From Carbon Isotope Composition in A Mediterranean Semi-Enclosed Marine System

Abstract

The origin and distribution of suspended organic matter, the trophic features and the stable carbon isotopic composition of particulate organic carbon (POC) were studied monthly in a Western Mediterranean semi-enclosed basin. Sampling stations were selected as a function of wind-exposure and the degree of vegetation cover and then compared with an adjacent unvegetated site. the predominant vegetation was seagrass (Posidonia oceanica and Cymodocea nodosa) and Caulerpa prolifera. Water samples were analyzed for total suspended matter (inorganic and organic fractions), photosynthetic pigments (chlorophyll-a and phaeopigments), dissolved organic carbon, particulate organic carbon and their isotopic composition. Temperature and salinity were also measured at the same sampling sites within range of Mediterranean limits. the suspended organic matter concentration was 1.77 ± 1.55 mg l^?1; the chlorophyll-a concentration was low (0.35 ± 0.24 μg l^?1); the disolved organic carbon concentration was 2,140 ± 2,010 μg l^?1; the particulate organic carbon concentration was 212 ± 106 μg l^?1 and the isotopic composition was 18.77 ± 2.51%_°. There were significant temporal differences except for phaeopigments, POC and its POC isotopic composition, and there were no spatial differences other than for δ¹³C. This picture highlighted a general seasonal trend and trophical features similar to adjacent sea.

Spatial differences in δ¹³C showed that the source of suspended organic matter was different between stations as that between sources and wind-hydrodynamic constraints. In     

Effects of polyaluminium chloride on the freshwater invertebrate Daphnia magna

In a number of countries across the world, aluminium in the form of polyaluminium chloride has been used in the treatment of freshwaters for the direct removal of cyanobacteria, or phosphorus removal, but knowledge about its effect on zooplankton species is poor. In our study, polyaluminium chloride toxicity was tested on both artificial and natural freshwaters for a better understanding and prediction of effects in real ecosystems. Our results indicate that prediction of effects in a real ecosystem based on standard ISO methods is insufficient, and tests with nontarget species (including invertebrates) should be done before each treatment using the water samples from the treated location. Effective concentrations of polyaluminium chloride can differ markedly according to the type of water composition used in the assay. Our experiments proved that EC₅₀ values can fluctuate between 9.89 and 54.29 mg·L^?1 of Al³⁺, and the toxicity is dominantly dependent on the treated water conductivity. This parameter seems to be the dominant source of different effects on zooplankton species after treatment and thus should be properly tested before each use of polyaluminium chloride as a treatment compound.     

Isotopic evidences for microbiologically mediated and direct C input to soil compounds from three different leaf litters during their decomposition

We show the potentiality of coupling together different compound-specific isotopic analyses in a laboratory experiment, where ¹³C-depleted leaf litter was incubated on a ¹³C-enriched soil. The aim of our study was to identify the soil compounds where the C derived from three different litter species is retained. Three ¹³C-depleted leaf litter (Liquidambar styraciflua L., Cercis canadensis L. and Pinus taeda L., δ¹³C_vsPDB ≈ ?43‰), differing in their degradability, were incubated on a C4 soil (δ¹³C_vsPDB ≈ ?18‰) under laboratory-controlled conditions for 8 months. At harvest, compound-specific isotope analyses were performed on different classes of soil compounds [i.e. phospholipids fatty acids (PLFAs), n-alkanes and soil pyrolysis products]. Linoleic acid (PLFA 18:2ω6,9) was found to be very depleted in ¹³C (δ¹³C_vsPDB ≈ from ?38 to ?42‰) compared to all other PLFAs (δ¹³C_vsPDB ≈ from ?14 to ?35‰). Because of this, fungi were identified as the first among microbes to use the litter as source of C. Among n-alkanes, long-chain (C27–C31) n-alkanes were the only to have a depleted δ¹³C. This is an indication that not all of the C derived from litter in the soil was transformed by microbes. The depletion in ¹³C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.     

Carbon- and oxygen-isotope composition of the cuttlebone of Sepia officinalis: a tool for predicting ecological information?

Analysis of the isotope composition of calcareous structures of marine organisms has proved useful in providing biological data. The present study constitutes the first detailed work undertaken on the isotope composition of coleoid cephalopods. We analysed the carbon- and oxygen-isotope composition [δ¹³C (CO²⁻ ₃) and δ¹⁸O (CO²⁻ ₃), respectively] of the cuttlebone aragonite of wild and cultivated specimens of Sepia officinalis Linnaeus, 1758. δ¹³C (CO²⁻ ₃) ranged from −2.94 to 1.00‰, δ¹⁸O (CO²⁻ ₃) from −0.18 to 2.08‰. The carbon-isotope composition is not in equilibrium with the carbon species of the ambient seawater, and does not reflect the deposition of CaCO₃ in seawater. The potential influence of environmental factors and biological processes on the carbon-isotope composition of the cuttlebone is discussed. In contrast to δ¹³C, the oxygen-isotope composition of cuttlebone aragonite appears to be in isotopic equilibrium with the ambient seawater. Seasonal changes in isotopic temperature revealed by our analyses agreed with changes in the temperature of the ambient seawater. CaCO₃ was deposited all year round. A maximum life span of 2 yr, a year-round spawning season, and variable growth rates among and within individuals have been inferred from the isotopic temperatures. Received: 14 April 1998 / Accepted: 26 November 1998     

Total peroxides in rainwater at two mountainous sites and in Mexico City,Mexico

Rainwater samples were collected in the western sector of Mexico City (MC) and at Rancho Viejo (RV), 80 km west-south-west of MC, from 2001 to 2005, and Orizaba City (OC), about 90 km from the Gulf of Mexico, where rainwater collections were only possible on some weekends in 2001. Rainwater samples were treated in the field, and analysed by fluorescence at the laboratory. The volume-weighted mean concentration (VWMC) of H₂O₂ was 13.2 μM at RV, and 11.2 μM in MC, for the period 2001–2005. The highest VWMC was observed in OC (21.6 μM). The VWMCs for each year were 9.5, 14.4, 11.5, 16.7, and 14.3 μM at RV, and 12.2, 12.2, 14.3, 11.8, and 9.9 μM in MC, for 2001–2005, respectively. Hydrogen peroxide in rainwater correlated significantly and negatively with sulfate in both MC and RV, but not, however, in OC. This study confirmed that H₂O₂ concentration in rainwater is controlled by a complex combination of rain intensity, washout processes and in-cloud formation of H₂O₂, acting simultaneously. This was suggested by the fact that rain intensity seemed to predominate in certain rain fractions of a rain event, while washout processes seemed to predominate in other fractions of the same rain event.     

Elemental Contamination of Rainwater by Airborne Dust in Tamale Township Area of the Northern Region of Ghana

Rainwater samples were collected from Tamale town in the 1997 and 1998 rainy seasons. During this period road construction in the Tamale area resulted in the generation of suspended dust in the atmosphere. Analysis of the samples for major ions showed elevated levels of Cl^–. Ion ratios with Cl^– (Na⁺/Cl^–, K⁺/Cl^–, Ca²⁺/Cl^–/Cl^– Mg²⁺/Cl^– and SO₄ ^2–/Cl^–) in rainwater samples were higher than the corresponding ratios in seawater. Some samples also showed elevated concentrations of Fe, Mn, Al and Zn, all of which except Zn showed a correlation with the dry periods between rainfall events. Consequently, it was concluded that dust generated from lateritic soils was probably the major cause of the increase in concentration of these metals. Aluminium and Fe concentrations were observed to be higher than the World Health Organization drinking water guide limits.     

Fluoride distribution in the environment along the gradient of a phosphate-fertilizer production emission (southern Brazil)

Airborne fluoride was determined in the rainwater, surface soil and groundwater along a gradient of emission of a phosphate fertilizer factory in Rio Grande, southern Brazil. Concentrations of fluoride in rainwater and groundwater achieved 3 mg l⁻¹ and 5 mg l⁻¹, respectively, and were dependent on pH. The fluoride deposited from emissions accumulated in a superficial horizon of soil in quantities comparable to those in the manufactured end-products—up to 23,000 mg kg⁻¹. Fluoride distribution in the environment is controlled by physical–chemical parameters of emission, rain intensity and soil properties. The highest fluoride concentrations were registered at a close distance of up to 2 km from the factory. The distribution of fluoride in groundwater resembled the same distribution in rainwater due to the high permeability of the local soils. Fluoride penetration to the groundwater also depended on the type of vegetation cover. The groundwater in woodland areas was less affected by contamination of fluoride than in the grassland areas, most probably because of the influence of eucalyptus throughfall, which increases the pH of wet precipitates.     

Ammonium regeneration and carbon utilization by marine bacteria grown on mixed substrates

We examined the impact of exposing natural populations of marine bacteria (from seawater collected near Woods Hole, Massachusetts, USA) to multiple nitrogen and carbon sources in a series of batch growth experiments conducted from 1989 through 1990. The substrate C:N ratio (C:N_s) was varied from 1.5:1 to 10:1 either with equal amounts of NH ₄ ⁺ and different amino acids or an amino acid mixture, all supplemented with glucose to maintain the C:N_s ratio equal to that of the respective amino acid, or with combinations of glucose and NH ₄ ⁺ alone. A common feature of the experiments involving amino acids was the concurrent uptake of NH ₄ ⁺ and amino acids that persisted as long as a readily assimilable carbon source (glucose in our case) was taken up. There was no net regeneration of NH ₄ ⁺ , even though catabolism of amino acids occurred. Regeneration of NH ₄ ⁺ was evident only after glucose was completely utilized, which usually occurred at the end of exponential growth. The contribution of¹⁵NH ₄ ⁺ to total nitrogen uptake by the end of exponential growth varied from ~60 to 80% when individual amino acids were present and down to ~24% when the amino acid mixture was added. These estimates are conservative because we did not account for possible isotope dilution effects resulting from amino acid catabolism. When NH ₄ ⁺ and glucose were the sole nitrogen and carbon sources, there was a stoichiometric balance between glucose and NH ₄ ⁺ uptake over a wide range of C:N_s ratios, leading to a constant bacterial biomass C:N ratio (C:N_B) of ~4.5:1. As a result NH ₄ ⁺ usage varied from 50% when the C:N_s ratio was 3.6:1, to 100% when the C:N_s ratio was 10:1. Gross growth efficiency varied from ~60% when NH ₄ ⁺ plus glucose were added alone or with the amino acid mixture, to 47% when the individual amino acids were used in place of the mixture. It is thus evident that actively growing bacteria will act as sinks for nitrogen when a carbon source that can be assimilated easily is available to balance NH ₄ ⁺ uptake, even when amino acids are available and are being co-metabolized.     

H and O isotopic differences in typhon and urban-induced heavy rain in Tokyo

Stable isotope ratios of hydrogen and oxygen of water are useful tracers of the hydrological cycle. For example, isotopes monitor the evapotranspiration in vegetated areas, local snow ice processes and stream water flow processes. δ¹⁸O and δD in rainwater reflect the processes of evaporation, condensation and precipitation. Heavy rains thus modify the stable isotope ratio of ground water, stream water and transpiration water vapor. However, the controlling factors of δ¹⁸O and δD are not clear. Here we analyzed the inorganic ion concentration and stable isotope ratio in 38 normal rainwater and 15 heavy rainwater samples were collected in Shinjuku, Tokyo, Japan, during four years from October 2012 to December 2015. Results show a decrease in δ¹⁸O and δD values with the total rainfall amount, thus highlighting the amount effect. δ¹⁸O and δD volume-weighted mean values in typhoon heavy rain were higher than the values estimated from amount effect, whereas δ¹⁸O and δD volume-weighted mean values in urban-induced heavy rain were lower. Typhoon heavy rain has high Na⁺ ratio and stable isotope ratios, while urban-induced heavy rain has low Na⁺ ratio and stable isotope ratio.     

Effects of nutrient limitation on toxin production and composition in the marine dinoflagellate Protogonyaulax tamarensis

Toxin production was measured by high pressure liquid chromatography (HPLC) when the marine dinoflagellate Protogonyaulax tamarensis (NEPCC 255) was grown under nitrogen or phosphorus limitation. The major toxins found in P. tamarensis (255) consisted of (N21-SO ₃ ^- )STX (11%), (N21-SO ₃ ^- )NeoSTX (44%), and [(N21-SO ₃ ^- )GTX₂ plus (N21-SO ₃ ^- )GTX₃] (20%). Total toxin content on a per cell basis was high for cultures in log phase (30 to 40 fmol cell^-1) and then decreased to ca 20 fmol cell^-1 as the cultures entered stationary phase. There was a gradual decrease in the toxin content per cell during nitrogen-limited stationary phase to ca 3 fmol cell^-1 or less. Phosphorus-limited cultures showed a markedly different response than nitrogen-limited cultures. Toxin content in P-limited cells dramatically increased at the start of stationary phase, reaching levels 3 to 4 times that observed in control and nitrogen-limited cultures. These results cannot be explained by changes in the average cell volume. Eventhough dramatic effects on the total toxin concentration were observed in response to nutrient limitation (N or P), the toxin composition (on a percent basis) remained constant. This suggests that the individual toxin composition of a given isolate is a fixed genetic trait and not a transient response to changing environmental factors.     

Oxygen and carbon isotopic composition of fish otoliths

Oxygen and carbon isotopic composition of the aragonite of fish otoliths was measured on 175 specimens comprising 24 different species in 1989 and 1990. All specimens but two came from the northern Adriatic Sea or the northern Tyrrhenian Sea (two freshwater specimens were studied for comparison with the marine fish). The data obtained confirm the results of previous research suggesting the existence of equilibrium conditions between the otolith aragonite and ambient water with respect to ·¹⁸O(CO₃ ^2-) values. Examination of one of the species indicated that the CaCO₃ of otoliths probably accumulates continuously over time, seasonal isotopic changes being clearly visible (from a set of radial spot samples) for both oxygen and carbon isotopes. The apparent isotopic equilibrium with ambient water suggests that the ¹⁸O(H₂O) of the endolymph is equal to that of seawater and considerably different from that of fish body water. In the case of ¹³C(CO₃ ^2-), isotopic equilibrium with dissolved carbon species in seawater is never reached, even though the contribution of metabolic CO₂ is variable among different species and even among different individuals of the same species. This rules out the possibility of using ¹³C(CO₃ ^2-) values obtained from fossil otoliths for paleoenvironmental and paleobiological conclusions.     

Tracing the sources of gaseous components (<Superscript>222</Superscript>Rn,CO<Subscript>2</Subscript> and its carbon isotopes) in soil air under a cool-deciduous stand in Sapporo,Japan

Radon (²²²Rn) and carbon dioxide were monitored simultaneously in soil air under a cool-temperate deciduous stand on the campus of Hokkaido University, Sapporo, Japan. Both ²²²Rn and CO₂ concentrations in soil air varied with atmospheric (soil) temperature in three seasons, except for winter when the temperature in soil air remained constant at 2–3°C at depth of 80 cm. In winter, the gaseous components were influenced by low-pressure region passing through the observation site when the ground surface was covered with snow of ~1 m thickness. Carbon isotopic analyses of CO₂ suggested that CO₂ in soil air may result from mixing of atmospheric air and soil components of different origins, i.e. CO₂ from contemporary soil organic matter and old carbon from deeper source, to varying degrees, depending on seasonal meteorological and thus biological conditions.