Seasonal Variation In Chemical Composition Research Articles

Seasonal Variations in Chemical Composition and Source Apportionment of Fine Particulate Matter (PM1) in an Urban Site of Jaipur City, Rajasthan

The present study was conducted with an aim to investigate the seasonal variation in mass concentration of fine particulate matter (PM1), their chemical composition, (water and soluble and non-soluble ions and other elements) and gaseous pollutants (SO2, NO2, CO and O3) at an urban site of Jaipur city in India. During summers, pollutants showed a reduction of 18.97%, 41.95%, 32.32% and 20.56% for PM1, NO2, SO2 and CO, respectively. In contrast, O3 showed an increase of 27%. The substantial reduction was also observed in the levels of secondary aerosols SO4 2- (71.15%), NO3-(21.86%), Cl- (65.63%) and K+ (8.16%). The elemental components Al, B, Be, Ca, Cu, Fe, Mn, Ni, and Pb showed a reduction in the range of 15.13 % (Al) to 71% (Cu). On the contrary, an increment was found in the levels of Ag (21.95%), Cd (62.5%), Cr (89.74%), Mg (10.43%) and Na (25.32%). Four factors were extracted by principal component analysis (PCA). In addition to the local sources, three stationary sources have been identified as contributing to the pollution load located in the WNW, NE and ENE direction of the site. It can be concluded that pollutant concentration and chemical composition of any area not only depend on the local emission, but nearby stationary sources and meteorology are significant contributors.

Seasonal Variations of Chemical Composition and Microbiological Quality of Camels Milk in Transhumance Nomadic Production System in Shandi Area, Northern Sudan

Transhumance production system is characterized by seasonal movement of the herders to make use of free-range pasture. In this study camel milk samples were collected during different seasons from different she camels’ rearing in transhumance system. The camel milk samples (n= 150) were collected from Western and Eastern Shandi, River Nile State, Sudan. The chemical composition (protein, lactose, total solids and density) and microbiological loads (total bacterial, coliform and yeast and mould) of camel milk were determined. The results showed that overall means for the total solids, protein and lactose content and density of camel milk samples collected from Eastern and Western Shandi during different seasons revealed 12.98±12.84%, 3.58±3.43% and 4.77±4.69% and 1.035±1.030 gm/cm3, respectively. The age and parity number of the she camel revealed highly significant (P<0.01) correlations when compared with total solids, protein, lactose and density. The milk yield was higher in camel reared in Eastern Shandi during winter and Western Shandi during autumn. Also, there were significant (P<0.05) differences in total bacterial, coliform and yeast and mould counts in camel milk collected from Western and Eastern Shandi during the different seasons. However non-significant (P>0.05) differences were found between the two locations in the microbial quality of camel milk. This study concluded that parity number, age of camel, seasons and pasture content are important factors contributing to the variations in camel milk chemical composition. Moreover, the transhumance production system of camel sustains uniform chemical composition of milk, while variations in the microbiological quality are observed.

The Seasonal Variation of Forage's Chemical Composition of a Semi-Arid Rangeland According to Altitude and Aspects

This study was carried out on Kop Mountain, which is located at the intersection of Eastern Anatolia and Eastern Black Sea in Turkey. Forage samples were taken from the semi-arid rangeland sites were analyzed for status of the chemical composition according to altitude and aspect. In addition, the seasonal variation of the chemical composition was investigated by repeated analyzes in 3 different periods. In terms of aspect, the highest crude protein ratio (13.40%) occurred in the north, the lowest ratio (10.11%) occurred in the east, while the higher crude protein ratio (11.88%) was observed in the backslope in terms of altitude. The highest crude protein rate (15.15%) was found in May. The highest rate (53.67%) was found in the east and the lowest (45.86%) in the North in terms of NDF. NDF rates in May, July, and October were 48.27%, 47.11%, and 58.17%, respectively. The highest value (33.30%) was recorded in the west and the lowest value (27.66%) was recorded in the North in terms of ADF. ADF values observed in May, July and October were determined as 26.98%, 30.93%, and 36.63%, respectively. According to the results of the research, it was determined that while the crude protein ratio decreased with the maturation of the plants, the elements forming the cell wall increased; and seasonal conditions changed and affected the forage quality.

Seasonal Variation in Chemical Composition, Ruminal Fermentation, and Biological Characteristics of Paulownia shan tong: In Vitro Potential Use by Sheep and Goats

This study was conducted to determine the seasonal variation (two seasonal harvests during winter and spring) in some chemical and biochemical characteristics of Paulownia shan tong leaves. To achieve this, we analyzed the chemical composition in terms of dry matter (DM), organic matter (OM), crude protein (CP), cell-wall content (neutral detergent fiber (NDF)), acid detergent fiber (ADF), acid detergent lignin (ADL), and lipids. The phenolic compounds (PC) and antioxidant activity (AA) of the leaves were also determined. In vitro gas production (GP) and nutrient degradability were evaluated using two ruminal-content donors (sheep and goats). Higher (p < 0.05) antioxidant activities were observed in the winter harvest of P. shan tong, while higher concentrations of OM (90.5%), lipids (3.02%), NDF (69.7%), ADF (54.8%), ADL (35.4%), total flavonoids (0.45 mg catechin equivalents/mg DM), and total phenolics (2.52 mg gallic acid equivalents/mg DM) were observed in the spring harvest. Higher asymptotic GP and rate of GP (p < 0.05) were observed when the leaves were incubated with rumen liquor of goats compared to sheep; however, higher (p < 0.05) lag time of GP and half-time of GP were observed with rumen liquor from sheep. Moreover, higher asymptotic GP, rate of GP, and half-time of GP were observed with the winter harvest of P. shan tong. Higher (p < 0.001) metabolizable energy, OM degradability, and microbial protein supplies were obtained when the leaves were incubated with rumen fluids from goats and from the winter harvest of P. shan tong compared to the spring harvest. In conclusion, based on the chemical composition and the kinetics of in vitro gas production, P. shan tong leaves seem to be characterized by a good nutritive value and could be considered as an alternative feed resource for ruminants.

Comparative metabolic profiling of olive leaf extracts from twelve different cultivars collected in both fruiting and flowering seasons

Olea europaea is an economically significant crop native to Mediterranean countries. Its leaves exhibit several biological properties associated to their chemical composition. The aqueous ethanolic extracts of olive leaves from twelve different cultivars were analyzed by high performance liquid chromatography coupled to photodiode array and electrospray ionization mass spectrometry (HPLC/PDA/ESI–MS/MS). A total of 49 phytochemicals were identified in both positive and negative ionization modes. The identified compounds belonged to four classes of secondary metabolites including secoiridoids, flavonoids, pentacyclic triterpenoids and various phenolic compounds. Seasonal variation in chemical composition among the studied cultivars was apparent in autumn and spring. Secologanoside, oleuropein, hydroxy-oleuropein, demethyl oleuropein, gallocatechin, luteolin-O-hexoside, diosmetin, oleanolic acid and maslinic acid were detected in all cultivars in both seasons. Oleuropein-O-deoxyhexoside was tentatively identified for the first time in olive leaf extracts; detected only in the Spanish cultivar Picual (PIC) collected in spring. Also, dihydroxy-oxooleanenoic acid and hydroxy-oxooleanenoic acid, two bioactive pentacyclic triterpenes, were identified. Principle component analysis (PCA) showed good discrimination among the studied cultivars in terms of their botanical origin. This study is considered the first study for non-targeted metabolic profiling of different olive leaf cultivars cultivated in Egypt.

Seasonal variation in chemical composition and contaminants in European plaice (Pleuronectes Platessa) originated from the west-coast of Norway

The seasonal effect on chemical composition and contaminants in European plaice (Pleuronectes platessa) captured in Norwegian waters was investigated in three seasons (September, December, April). Fillets were compared by analysing proximate composition, lipid and protein profile, including fatty acids, lipid class distribution, free and total amino acids. Trace elements and polychlorinated biphenyls (PCB) were determined to assess the potential health risk of consumption. Results on proximate composition reveal differences in water, ash, lipid, and protein content between the seasons. Beneficial levels of n3 fatty acids, including a sufficient n3/n6 ratio (6.1–8.7), were observed. Phospholipids and cholesterol were negatively correlated with total lipid content, adding to high triacylglycerol concentrations observed in December samples. No elevated levels for toxic trace elements, yet detrimental concentrations of dioxin-like PCB-118 were found. Results show that European plaice is highly nutritious with desirable amino and fatty acid profile throughout the year, and with few potential risks.

Nutritive Value of Cistus ladanifer L. for Ruminants: Seasonal Variation of Chemical Composition, Digestibility, and Antioxidant Activity of Its Morphological Fractions

Cistus ladanifer has been used in ruminants feeding systems, but there is no information about the seasonal variation in chemical composition and nutritional value of each morphological fraction during its growth cycle. This study characterized the morphological fractions of C. ladanifer (leaves, stems, flower buds, flowers, and seed heads) throughout the year in chemical composition, in vitro digestibility, and antioxidant activity. The leaves were the morphological fraction more variable throughout the seasons, being characterized by low protein level (48.5–114 g/kg dry matter (DM)), moderate cell-wall content (240–267 g NDF/kg DM), high levels of condensed tannins (CT) (131–246 g/kg DM), and low in vitro organic matter digestibility (IVOMD) (29.3–34.3%). The distinctive chemical composition among various morphological fractions allowed the identification of four distinct groups, the first composed by stems, the second by the leaves, the third by the seed heads, and the last one by the flower buds and flowers. All the morphological fractions are sources of bioactive compounds namely phenolic compounds. Leaves are the fraction with higher nutritive value, especially when collected during winter and spring.

Seasonal Variation in Chemical Composition of Total Suspended Particles During the COVID-19 Pandemic in the Source Area of Urumqi River, Tianshan, China

The research of atmospheric aerosol in mountain glacier areas has attracted more and more people’s attention. For the first time, a field observation study of total suspended particles (TSPs) for four seasons from September 2019 to August 2020 was carried out at the Tianshan Glaciological Station in the source area of Urumqi River, East Tianshan Mountains, China. The TSPs presented typical seasonal characteristics of high in autumn and low in winter, with the annual average value of 181 ± 170 μg m−3. Concentrations of Ca2+, SO42−, NO3−, Cl−, NH4+ and K+, OC, EC were elevated in autumn. The influence of stationary source emissions was stronger than mobile sources, which was explained by the average ratio of NO3−/SO42− (0.31 ± 0.17). The concentration of secondary organic carbon (SOC) was higher in summer and autumn, especially in summer, indicating that secondary formation processes of organic aerosols were frequent in summer. Impact of fossil fuel combustion sources were evident over the Glaciers, corroborated by the diagnostic mass ratios of OC/EC (0–21.4, 3.38) and K+/EC (0–0.31, 0.08). The factor analysis illustrated that aerosols were mainly affected by rock salt, dust, coal combustion, and automobile exhaust. The local sources made significant contributions to TSPs in the source of Urumqi River by the results of Results of Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and potential source contribution function (PSCF).

Essential Oils from Piper caldense C. DC. and Piper xylosteoides (Kunth) Steud.: Seasonal Variation of the Chemical Composition and Antimicrobial Activity.

The essential oils (EOs) chemical composition can be affected by several environmental factors, impacting their desired biological activities. In this sense, this work aimed to evaluate the seasonal variation of the chemical composition and antimicrobial activity of Piper caldense and Piper xylosteoides leaves EOs. Their chemical composition was determined by GC/MS and GC-FID analyses, resulting in the identification of eighty compounds. P. caldense EOs were mainly consisted of sesquiterpene hydrocarbons, whereas in P. xylosteoides EOs, monoterpene hydrocarbons were predominant. EOs from both species strongly inhibited B. subtilis (MIC=0.25 mg mL-1 ), while only P. caldense EOs showed strong activity against S. aureus (MIC=0.50 mg mL-1 ). P. caldense spring EO showed the broadest spectrum of antimicrobial action amongst all samples. For each species, PCA seasonally differentiated EOs chemical composition. In addition, as expected, PCA of all samples showed a distinction between the two species. This study has successfully demonstrated the importance of evaluating the seasonal variation of EOs chemical composition and antimicrobial activity in obtaining a product with the desired properties.

Seasonal variation in chemical composition and in-vitro gas production of woody plant species of semi-arid condition of Namibia

Seasonal variation in chemical composition and in-vitro gas production of woody plant species of semi-arid condition of Namibia

Seasonal Variation in Chemical Composition of Size-Segregated Aerosols Over the Northeastern Arabian Sea

Water-soluble species constitute a significant fraction (up to 60–70%) of the total aerosol loading in the marine atmospheric boundary layer (MABL). The “indirect” effects, that is, climate forcing due to modification of cloud properties depend on the water-soluble composition of aerosols. Thus, the characterization of aerosols over the MABL is of greater relevance. Here, we present 1-year long aerosol chemical composition data of PM10 and PM2.5 at a costal location in the northeastern Arabian Sea (Goa; 15.45°N, 73.20°E, 56 m above the sea level). Average water-soluble ionic concentration (sum of anion and cation) is highest (25.5 ± 6.9 and 19.6 ± 5.8 μg·m−3 for PM10 and PM2.5, respectively) during winter season and lowest during post-monsoon (17.3 ± 9.1 and 14.4 ± 8.1 μg·m−3 for PM10 and PM2.5, respectively). Among water-soluble ionic spices, SO42- ion was found to be dominant species in anions and NH4+ is dominant in cations, for both PM10 and PM2.5 during all the seasons. These observations clearly hint to the contribution from anthropogenic emission and significant secondary inorganic species formation. Sea-salt (calculated based on Na+ and Cl−) concentration shows significant temporal variability with highest contribution during summer seasons in both fractions. Sea-salt corrected Ca2+, an indicator of mineral dust is found mostly during summer months, particularly in PM10 samples, indicates contribution from mineral dust emissions from arid/semiarid regions located in the north/northwestern India and southwest Asia. These observations are corroborated with back-trajectory analyses, wherein air parcels were found to derive from the desert area in summer and Indo-Gangetic Plains (a hot spot for anthropogenic emissions) during winter. In addition, we also observe the presence of nss-K+ (sea-salt corrected), for PM2.5, particularly during winter months, indicating influence of biomass burning emissions. The impact on aerosol chemistry is further assessed based on chloride depletion. Chloride depletion is observed very significant during post-monsoon months (October and November), wherein more than 80 up to 100% depletion is found, mediated by excess sulfates highlighting the role of secondary species in atmospheric chemistry. Regional scale characterization of atmospheric aerosols is important for their better parameterization in chemical transport model and estimation of radiative forcing.

Evaluation of the Effect of Brazilian Savanna (Cerrado) Seasons in Flavonoids and Alkaloids Accumulation: The Case of Duguetia furfuracea

Environmental factors can influence secondary plant metabolism, inducing seasonal variation in chemical composition. Few works report how the seasons of Brazilian savanna (Cerrado), rainy and dry, impacts plant metabolism. We investigated the seasonal effect on the production of secondary metabolites in Duguetia furfuracea. Leaves of three individuals were collected monthly for one year and analyzed by ultra-fast liquid chromatography coupled to diode array detector and mass spectrometry (UFLC-DAD-MS), partial least squares-discriminant analysis (PLS-DA), hierarchical cluster analysis (HCA), volcano plot, and Pearson correlation. The main chemical classes found were benzyltetrahydroisoquinoline derivatives and flavonoids. Alkaloids are virtually perennial, with qualitative variation during the year, and flavonoids accumulate during the rainy season. Dew point temperature seemed to be the most representative weather indicator in the metabolite change. These results showed for the first time the effect of the Cerrado environment on the levels of flavonoids and alkaloids in Duguetia furfuracea. They could be useful for exploring this species since it is used in popular medicine and accumulates valuable secondary metabolites.

Seasonal Variation of Chemical Composition, Fatty Acid Profile, and Sensory Properties of a Mountain Pecorino Cheese.

This study aims to assess the compositional traits and sensory characteristics of a traditional pecorino cheese associated with management and feeding system seasonality. The study was carried out on two mountain dairy farms using an outdoor, pasture-based system from April to October (OutS), and an indoor system (InS) during the rest of the year. Outdoor-produced milk had higher fat content and a tendency for protein and somatic cell count to be higher. The OutS cheeses showed higher dry matter and fat content, higher percentages of unsaturated fatty acids, C18:3, cis-9, trans-11 conjugated linoleic acid, and trans-11 C18:1, and lower percentages of C14:0 and C16:0. These modifications in fatty acid composition determined the reduction of the atherogenic index. The OutS cheeses also displayed higher intensity of almost all sensory attributes, including odor, flavor, taste, and texture descriptors. The outdoor system partly reduced the liking of consumers for pecorino. However, changes in the productive process leading to an increment in the water content and softness of the cheeses (i.e., controlled humidity and temperature during ripening) may increase the overall liking of pasture-based products, thus promoting the consumption of healthier foods.

Essential oil of Cymbopogon citratus cultivated in Egypt: seasonal variation in chemical composition and anticholinesterase activity

The yield of essential oil obtained by hydrodistillation of Cymbopogon citratus fresh leaves ranged from 0.15% to 0.46% w/w; being the highest in spring and the lowest in winter. The oil sample obtained in winter exhibited a moderate acetylcholinesterase inhibitory activity (IC50 2.86 ± 0.17 mg/mL), compared to physostigmine (IC50 0.012 mg/mL), while other samples were relatively weak (IC50 values of 2.86–5.40 mg/mL). In all samples, oxygenated monoterpenes were predominating (73.22–89.32%). GC-MS identified a total of 61, 25, 50 and 63 components in oil samples obtained in spring, summer, autumn and winter, respectively. Citral content was the highest in autumn and summer samples (82.02% and 80.01% citral; respectively) and the lowest in winter sample (60.01%). Citral, isolated from the oil demonstrated a relatively potent anticholinesterase activity (IC50 0.21 ± 0.01 mg/mL).

Distribution of dissolved matter in the Yenisei river estuary and adjacent water area of the Kara sea and its interannual variability

The distribution of dissolved matter (major ions, nutrients, and trace elements) in the Yenisei River estuary and adjacent water area was studied according to the natural observations data from 20092016. These results were compared to the literature data of hydrochemical researches of this region. It was shown that transport of major ions (Na, K, Mg, Ca, SO4) and some trace elements (Li, Rb, Cs, Sr, B, F, Cr, Ge, As, Mo, U) is described by the stable in the long-term period equations of conservative mixing between riverine and seawater masses. Alkalinity also belongs to conservative components; however this parameter exhibits substantial spatiotemporal variability of the distribution caused by complex hydrological structure of the Yenisei Bay and adjoining part of the Kara Sea. Concentrations of Pmin, Si, and V in the desalinized waters of photic layer decreases seaward during vegetation period owing to uptake by phytoplankton. The losses of these elements reach 3057, 30, and 9% of their supply by river runoff, respectively. The content of dissolved Pmin and V in the intermediate and near-bottom layers of the Yenisei River estuary strongly increases with increase of salinity due to regeneration of precipitated organic matter, whereas silica remineralization is much less pronounced. Barium in the all estuary is intensively desorbed from river suspended matter in the quantity reaching 20100% of its dissolved forms input with river runoff depending on seasonal variations of chemical composition of the last. The transport of dissolved forms of heavy metals (Mn, Fe, Pb) and elements-hydrolyzates (Al, Ti, Y, La, Ce, Pr) in the mixing zone between the riverine and seawater masses is probably controlled by the coagulation and flocculation of organic and organomineral colloids, which is indicated by decrease in the concentrations of these elements at the beginning of salinization (for 2061%) with subsequent approximation to the seawater mass characteristics.

Seasonal variations of chemical composition of PM2.5 fraction in the urban area of Krakow, Poland: PMF source attribution

The mass concentration of PM2.5 fraction in the atmosphere of Krakow, Poland, is 2.6 times higher in winter than in summer. Similar observations were made for countries with very low temperature during cold season as discussed by Rogula Kozlowska et al. (Air Qual Atmos Health 7:41-58, 2014, Int J Environ Res Public Health 13:715, 2016), Jeong et al. (Atmos Pollut Res 2:158-171, 2011), and Zwozdziak et al. (J Aerosol Sci 103:38–52, 2017). Fossil fuel combustion for heating of individual households is mainly responsible for high air pollution levels in urban areas during winter season as reported by Junninen et al. (Environ Sci Technol 43:7964–7970, 2009). Elemental concentrations were determined by energy dispersive X-ray fluorescence method, whereas ion concentrations were measured by ion chromatography. In addition, concentrations of elemental carbon (EC) and organic carbon (OC) were determined using OC/EC analyzer. Some elements like Br, Pb and Cl−, NO3−, NH4+ ions show significantly higher concentrations during winter, whereas in summer, higher Ca concentration was observed. The positive matrix factorization (PMF) receptor method was used for identification of air pollution sources and evaluation of their contribution to PM2.5 burden in the local atmosphere. Selected chemical species were used as indicators of particular sources of air pollution. Four source categories were identified through PMF analysis: (i) combustion, (ii) secondary aerosols, (iii) soil/industry/traffic, and (iv) biomass burning. For days with high PM2.5 concentrations (winter season), the contribution of combustion sometimes reaching 55% of PM2.5 mass was identified, whereas for days with low PM2.5 concentrations, it was reduced to approximately 28%.

Effect of Seasonal Variation on Chemical Composition and Physicochemical Properties of Hedychium spicatum Rhizomes Essential Oil

Effectiveness of medicinal plants dependents upon chemical composition and amount of active constituents that present in the species, which may be highly influenced by different factors such as, growing conditions, seasons, climatic conditions, sun light exposure and altitude etc. Therefore the present work aims to study the effect of different seasons on physicochemical profile of Hedychium spicatum rhizomes essential oil from Uttarakhand. The yield (%) of H. spicatum rhizomes essential oil was varying from 1.16 ± 0.012 % to 1.64 ± 0.018 % on moisture free basis. Seasonal variation in chemical composition of H. spicatum essential oil obtained in different seasons was determined by GC/MS analysis and total 65 peaks were identified. 1,8-cineole, α-cadinol, α-elemol and τ-muurolol were present in essential oil samples collected in different seasons. The major chemical compounds of H. spicatum essential oil in rainy and summer seasons were 1, 8-cineole (21.18 % and 21.81 %) and α-cadinol (18.43 % and 17.49 %). While α-elemol (16.44 %) and α-cadinol (15.99 %) were found major compounds in autumn season. The main compounds of winter were α-cadinol (18.79 %) and 1,8-cineole (14.83 %). Results of GC/MS and physicochemical analysis revealed that, different seasons affect chemical composition and physicochemical properties viz. yield (%), saponification value, acid value, ester value and glycerol content significantly.

Seasonal and reproductive variation in chemical constituents of scent signals in wild giant pandas.

Seasonally reproducing animals show many behavioral and physiological changes during the mating period, including increased signaling for intrasexual competition and mate attraction. We collected 102 anogenital gland secretions (AGS) from marking trees in Foping Nature Reserve, and used gas chromatography mass spectrometry analyze these chemical composition. Of these marks, all but one were from males, confirmed with DNA analysis. We found that several chemical constituents, especially volatile compounds, is present only during the mating season and that the relative abundance of many compounds changed as a function of breeding season, whereas nonvolatile compounds were lower in the mating season. This seasonal variation in chemical composition of AGS most likely plays an important role in governing giant panda reproduction, including mate location, attraction, and male-male competition. The chemical properties of many of these putative chemosignals-such as volatility and longevity-are suggestive of these roles, and undoubtedly contribute to successful reproduction for this species with a characteristically sophisticated chemical communication system. We also found a number of important differences between the chemical constituents of AGS from wild pandas and those found in previous studies with captive pandas, suggesting that inappropriate chemosignal composition may contribute to poor reproductive success in captive breeding programs.

Characterizing Major Controls on Spatial and Seasonal Variations in Chemical Composition of Surface and Pore Brine of Maharlu Lake, Southern Iran

Maharlu Lake with Na–Cl water type is the terminal point of a closed basin in southern Iran. A total of 10 water samples from two rivers discharging to the lake and 78 water samples of surface and pore brine of Maharlu Lake have been collected from different depths (surface, 20, 50 and 100 cm) of four sampling stations along the lake during a period of lake water-level fluctuation (November 2014–July 2015). To investigate chemical interaction between lake surface water and shallow pore water and to understand the major factors governing chemical composition of Maharlu brine, concentrations of major and minor (boron, bromide and lithium) solutes, pH and total dissolved solids have been measured in collected water samples. Saturation indices of evaporite minerals in collected water samples have been also calculated. The chemical behavior of dissolved solutes and evaporative evolution of the lake brine during a hydrological period have been simulated using PHREEQC. The results of our investigations indicated that chemical composition of lake surface water and pore brine of Maharlu Lake are mainly connected with lake water-level fluctuations and distance from input rivers (and depth), respectively. Hydrochemical investigations and statistical analysis showed that the brines chemistry of Maharlu is mainly controlled by three processes: brine evaporative evolution, dissolution–precipitation and diagenetic evolution of secondary carbonates.

Seasonal variation of chemical composition and source apportionment of PM2.5 in Pune, India.

Particulate matter with size less than or equal to 2.5μm (PM2.5) samples were collected from an urban site Pune, India, during April 2015 to April 2016. The samples were analyzed for various chemical constituents, including water soluble inorganic ions, organic carbon (OC), and elemental carbon (EC). The yearly mean total mass concentration of PM2.5 at Pune was 37.3μg/m3, which is almost four times higher than the annual WHO standard (10μg/m3), and almost equal to that recommended by the Central Pollution Control Board, India (40μg/m3). Measured (OC, EC) and estimated organic matter (OM) were the dominant component (56±11%) in the total particulate matter which play major role in the regional atmospheric chemistry. Total measured inorganic components formed about 35% of PM2.5. Major chemical contributors to PM2.5 mass were OC (30%), SO42- (13%), and Cl- and EC (9% each). The high ratios of OC/EC demonstrated the existence of secondary organic carbon. The air mass origin and correlations between the various components indicate that long range transport of pollutants from Indo-Gangetic Plain (IGP) and Southern part of the Arabian Peninsula might have contributed to the high aerosol mass during the dry and winter seasons. To our knowledge, this is the first systematic study that comprehensively explores the chemical characterization and source apportionment of PM2.5 aerosol speciation in Pune by applying multiple approaches based on a seasonal perspective. This study is broadly applicable to understanding the differences in anthropogenic and natural sources in the urban environment of particle air pollution over this region.