Seasonal Variations In Concentrations Research Articles

Lithological controls of dissolved trace elements: carbonate versus silicate

Trace elements in river waters can give information about chemical weathering and aqueous environments, but the systematics of trace elements in river waters have been poorly understood. Here, concentrations of dissolved trace elements were determined to investigate factors controlling their seasonal and spatial variations in the Han River Basin (HR), South Korea. Two major branches, the North Han River (NHR) and South Han River (SHR), differed largely in concentrations of their trace elements (e.g., As, B, Co, Li, Ni, and U), with the NHR having low concentrations and the SHR having high concentrations. This difference can be mainly attributed to the underlying lithology of the watersheds, namely, silicates in the NHR and carbonates plus clastic sediments containing black slate rich in trace elements in the SHR. Seasonally, concentrations of trace elements such as Al, Co, Fe, and Rb in the NHR were higher in summer, indicating that these trace elements exist as a colloid-borne form because of intensive physical weathering in the NHR. In contrast, the SHR showed little or no seasonal variation in concentrations of those trace elements.

Radon measurements and effective dose from radon inhalation estimation in the Neapolitan catacombs

In this study, the indoor radon activity concentrations have been measured in the Neapolitan catacombs using LR115 detectors. The detectors were exposed for two quarters, one in the warm season and the other in the cold. This has allowed one to evaluate the seasonal variations of concentrations, while the diurnal variations were evaluated performing continuous measurements by a Radim 5 monitor. The authors found that radon concentrations were lower in winter than in summer. Based on their values, taking into consideration the working hours in the catacombs and the equilibrium factor of 0.4, the effective dose to workers was estimated.

Occurrence, seasonal variation and inhalation exposure of atmospheric organophosphate and pyrethroid pesticides in an urban community in South China

The shift in pesticide usage patterns demands a better understanding of the occurrence, fate and exposure risk of atmospheric current-use pesticides (CUPs). Air samples collected in different seasons from an urban community in Guangzhou, China were analyzed to investigate seasonal variation, gas–particle partitioning and inhalation exposure of atmospheric organophosphate and pyrethroid pesticides. Chlorpyrifos and eight pyrethroids were detected in the air samples and the total concentrations of the nine CUPs ranged from 150 to 3816pgm−3. Chlorpyrifos and cypermethrin were the most dominant CUPs detected in the atmosphere, accounting for 68% and 15% of the total CUPs, respectively. Seasonal variation in concentration was observed for most CUPs, with peak concentrations occurring in summer and fall, which was consistent with their application patterns. Partitioning of chlorpyrifos between gas and particle phases was also seasonally-dependent, with more chlorpyrifos found in the gas phase in summer and fall. Additionally, gas–particle partitioning analysis suggested that chlorpyrifos might experience long-range transport. Evaluation of potential exposure from inhalation of atmospheric CUPs suggested that children, toddlers and infants had the highest exposure, but the risk quotients were low for all age groups when annual average concentrations were used as exposure metrics. Exposure risk was higher in summer and fall than the annual average level due to higher atmospheric pesticide concentrations, longer exposure times and more pesticides being in the gaseous form.

Plasma 25-Hydroxyvitamin D, Hormonal Contraceptive Use, and Cardiometabolic Disease Risk in an Ethnically Diverse Population of Young Adults

Objectives: The relationship between vitamin D and cardiometabolic disease risk across ethnic groups is unclear, and it is not known whether the use of hormonal contraceptives (HCs), which affect vitamin D metabolism and are also associated with cardiometabolic disease risk, modifies this relationship. Our objectives were to determine the prevalence of vitamin D deficiency (plasma 25-hydroxyvitamin D [25(OH)D] < 30 nmol/L) to assess seasonal variation in concentrations of 25(OH)D, and to examine whether 25(OH)D is associated with cardiometabolic biomarkers across ethnic groups and across men, female HC nonusers, and female HC users in an ethnically diverse population of young adults living in Canada. Methods: The study population consisted of Caucasian, East Asian, and South Asian individuals (n = 1384, 69% female) aged 20–29 years. Participants provided overnight fasting blood samples, from which plasma 25(OH)D and cardiometabolic biomarkers were measured. Vitamin D status distributions were compared using χ2 tests, and analysis of covariance (ANCOVA) was used to examine seasonal variations in 25(OH)D, as well as the association between 25(OH)D and cardiometabolic biomarkers, across groups. Results: Plasma 25(OH)D concentrations fluctuated seasonally among Caucasians and East Asians and across men, female HC nonusers, and female HC users, but they remained low year-round in South Asians, half of whom were vitamin D deficient. Vitamin D deficiency was associated with higher insulin, homeostasis model assessment–estimated insulin resistance (HOMA-IR), and homeostasis model assessment (HOMA)-beta among Caucasians and East Asians and among men and female HC nonusers and with higher triglycerides among men only. No biomarkers were associated with 25(OH)D among South Asians and female HC users, although nonsignificant trends were observed for higher markers of glycemic dysregulation in those who were vitamin D deficient in both groups. Conclusions: Vitamin D deficiency varies between ethnic groups and is particularly high among South Asians, and it is associated with biomarkers of glycemic dysregulation; however, HC use among women may attenuate this association. Given the widespread use of HCs by women throughout the world, a better understanding of the extent to which these medications may modify the relationship between vitamin D and processes related to disease is warranted.

A Statistical Appraisal to Hydrogeochemistry of Fluoride Contaminated Ground Water in Nayagarh District, Odisha

Abstract: Seasonal variation of ground water in Nayagarh district, Odisha is determined by analysing both pre and post monsoon water samples. The high fluoride content is an endemic problem in the area and special attention was attached to the point. The chemical compositions of the ground water of the area are dominated by CaCl, NaCl and mixed CaMgCl types in pre-monsoon and CaHCO3-mixed CaMgCl type in post-monsoon. This is largely due to chemical weathering of Eastern Ghats Mobile Belt rock types. Increasing alkalinity vis-a-vis F concentration in pre-monsoon is associated with sodium-bicarbonate water types having high pH (&amp;gt;7) and low calcium and magnesium contents. The percentage of total high fluoride containing water samples is nearly double in pre-monsoon than in post-monsoon. During both the seasons, pH values indicate mildly alkaline to weakly acidic nature of the water samples. Fluoride concentration has good correlation with pH in pre-monsoon whereas in post-monsoon it shows good correlation with Fe. Facies analysis indicates that water is becoming predominantly Ca-Na cation and Cl-SO4-HCO3 anion type in pre-monsoon than Ca-Mg type and HCO3- Cl-SO4 type in post-monsoon. The seasonal variations in concentrations of anthropogenic components demonstrate that the groundwater system is very less liable to pollution by human activities.

Occurrence of disinfection by-products in tap water distribution systems and their associated health risk

The concentrations of trihalomethanes (THMs), including chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and haloacetic acids (HAAs; monochloroacetic acid, monobromoacetic acid, dibromoacetic acid, dichloroacetic acid, and trichloroacetic acid) were measured in tap waters passing through water distribution systems of six water treatment plants in Seoul, Korea, and their associated health risks from exposure to THMs through ingestion, dermal contact, and inhalation were estimated using a probabilistic approach. The concentration ranges for total THMs and HAA5 were 3.9-53.5 and <LOD-49.5 μg/L, respectively. Among DBPs, chloroform, bromodichloromethane, dichloroacetic acid, and trichloroacetic acid were the most frequently detected. Spatial and seasonal variations in concentrations of THMs and HAAs in the six water distribution systems were significant (P < 0.001).The mean lifetime cancer risks through ingestion, dermal contact, and inhalation during showering ranged as 7.23-10.06 × 10(-6), 2.19-3.63 × 10(-6), and 5.22-7.35 × 10(-5), respectively. The major exposure route to THMs was inhalation during showering. Sensitivity analysis showed that shower time and shower frequency had a great impact on the lifetime cancer risk by the exposure to THMs in tap water.

Seasonal variations in concentrations of macro- and micronutrients in three species of brown seaweed

Abstract We studied variations through 1 year in concentrations of several macronutrients (C, N, P, Na, K, Ca, Mg, S) and micronutrients (Fe, Mn, Cu, Zn) and water content in tissues of the brown seaweeds Ascophyllum nodosum, Fucus vesiculosus and Fucus spiralis at two sites in a coastal embayment in northwest Spain. The annual mean concentrations of the nutrients in A. nodosum were very similar at both sampling locations. There were no significant differences between sites in the concentrations of N, P, Na, K, Ca, S, Fe, Mn or Cu, the C:N or N:P ratios or in the water content, whereas the chemical composition of this species was notably different at the site where it coexisted with F. vesiculosus (the only parameters that were not significantly different were concentrations of Ca, Cu and the N:P ratio). The C:N:P ratios and the clear seasonal variability in N in all species, with minimum values in summer, suggest limitation by this element. Along with N, K was the only other element that varied throughout the seasons in all of the species, and this was most notable in F. vesiculosus. Minimum concentrations of K were also observed in summer, which might indicate limitation by this element. Seasonal variations in C were only observed in the Fucus species; they followed a reverse trend from those of N and K, as the highest levels occurred in summer. The highest concentrations of P and Zn in F. vesiculosus were also observed in spring. No obvious seasonal trends were observed in the remaining minerals.

Seasonal Monitoring of Cardiovascular and Antiulcer Agents' Concentrations in Stream Waters Encompassing a Capital City.

Nowadays monitoring pharmaceutical residues from surface waters is a widespread analytical task. Most of the studies are conducted from river waters or sewage treatment plants and mainly in Western Europe or North America. Such studies are seldom published from Eastern Europe, especially from stream waters, even though the prescription and consumption patterns of drugs as well as wastewater treatment procedures are very dissimilar. In Hungary the active substance of the most often prescribed drugs are cardiovascular and antiulcer agents. Hence in our study compounds belonging to these two groups were seasonally monitored in two main streams encompassing the Buda side of the Hungarian capital city and flowing into the Danube. To obtain data on the occurrence, fate, and seasonal variation of the compounds, samples were taken from altogether eleven points located near wastewater treatment plants and confluences. The results gave no identifiable pattern in the seasonal variation of concentrations but the contribution of the tributaries and wastewater treatment plants could be followed as expected. From the runoff corrected estuary concentrations the annual contribution of these streams to pharmaceutical pollution of the Danube could be estimated to be in excess of 1 kilogram for atenolol, famotidine, metoprolol, ranitidine, and sotalol.

Diurnal and seasonal variations of concentration and size distribution of nano aerosols (10-1100 nm) enclosing radon decay products in the Postojna Cave, Slovenia

At the lowest point along the tourist route in the Postojna Cave, the activity concentration of radon ((222)Rn) short-lived decay products and number concentration and size distribution of background aerosol particles in the size range of 10-1100 nm were measured. In the warm yearly season, aerosol concentration was low (52 cm(-3)) with 21 % particles smaller than 50 nm, while in the cold season, it was higher (1238 cm(-3)) with 8 % of <50 nm particles. Radon activity concentrations were 4489 and 1108 Bq m(-3), and fractions of unattached radon decay products were 0.62 and 0.13, respectively.

Seasonal variations of concentrations, profiles and possible sources of polycyclic aromatic hydrocarbons in sediments from Taihu Lake, China

Purpose Obtaining a better understanding of the concentrations and origins of polycyclic aromatic hydrocarbons (PAHs) in the sediments Taihu Lake, China, is of paramount importance for the environmental protection and remediation of this lake. To investigate temporal and spatial variations in PAH concentrations, composition and possible source categories, 29 sediment samples were collected from Taihu Lake during both the flooding and dry seasons of the lake.

Peculiarities of seasonal variations of atmospheric aerosol concentration in the surface air of Moscow environs

The seasonal variations of the concentration of particles of different sizes in the atmospheric surface layer are studied on the basis of the data of daily measurements of atmospheric aerosol characteristics in the town of Dolgoprudny (20 km from the center of Moscow) carried out in 2006–2009. It is revealed that the steady variations of monthly mean aerosol concentration are observed within the particle diameter interval of 0.02–1 μm. The annual course of concentration of these particles has two maxima, in February-March and in September–October, and one minimum in June. The concentrations of particles with the size of 0.01–0.02 μm defined by the general atmospheric background and the concentrations of particles of >1 μm associated with the local sources do not have clearly pronounced seasonal variations. It is shown that the regularities of the annual concentration variations of particles with the size of 0.02–1 μm are mainly explained by the sign and value of the lapse rate in the layer up to 925 hPa that indicates the prevalence of the vertical mixing in the processes of aerosol scattering in the surface layer as compared with the horizontal transfer.

TEMPORAL AND SPATIAL TRENDS OF TOTAL ALIPHATIC HYDROCARBONS OF DIESEL RANGE AND TRACE ELEMENTS IN SEDIMENTS AND MUSSELS OF THE CORRAL BAY AREA, VALDIVIA, SOUTH CENTRAL CHILE

Sediments and mussel specimens of Mytilus chilensis were analyzed for organic pollutant fingerprints and heavy metals in the Corral Bay area of Valdivia, South Central Chile during the period 2003-2004. GC-MS analysis show hydrocarbon fingerprints corresponding mainly to mixed inputs of aliphatic hydrocarbons of the TPH-diesel fraction and biogenic hydrocarbons, indicating low to medium contamination by petroleum hydrocarbons with high biodegradation of petroleum in sediments at Las Coloradas, La Escuela and Corral Bay (C 17 /Pri < 1 and C 18 /Phy < 1). Mussel TPH fingerprints show weathered hydrocarbons resulting in a zone of increased concentration of cyclic respect to acyclic aliphatic components (UCM), indicating the presence of petroleum hydrocarbons. No temporal variation the in concentration of TPH-diesel found in sediments as well as mussels were observed except for samples collected during January 2004. TPH concentration levels in the sediments varied from 0.4 µgg-1 to 33.8 µgg-1 d.w. whereas in mussels varied between 61 µg g-1 and 287 µgg-1 d.w. Heavy metals were also analyzed by atomic absorption spectrometry and low concentration as well as no seasonal variations of concentration were found in mussels at each sampling point and a relatively even distribution of metals among stations was observed. Maximum concentrations in all sampling points of sediments were found for Fe (24128-43791 µgg-1) and Mn (181-388 µgg-1) while the minimum concentration was found for Pb (nd-12 µgg-1). According to the Sediment Quality Guidelines (SQGs-NOAA), the concentration levels of Cu and As in all sediment sampling points are above the “Effects Range-Low” (ERL), indicating that there may be a probable toxicity effect over the biota and attention must be paid on a moderate range of priority.

Cladosporium spores in the air of Szczecin

Moulds are common aeroallergens and &lt;i&gt;Cladosporium&lt;/i&gt; is considered to be the most prevalent of them. The objective of the studies was to determine the seasonal variation in concentrations of &lt;i&gt;Cladosporium&lt;/i&gt; spores due to meteorological parameters. The meteorological parameters analysed were maximum air temperature, relative humidity, amount of precipitation and wind speed. The greatest threat from &lt;i&gt;Cladosporium&lt;/i&gt; allergens was posed from the middle of May (2004, 2006) and June (2005) till the middle of October (2005) and in the end of October (2004) till the middle of November (2006). Statistically significant correlations were found among the &lt;i&gt;Cladosporium&lt;/i&gt; spore count in the air and maximum air temperature in all the analysed seasons, and amount of precipitation only in one season. The spore count of &lt;i&gt;Cladosporium&lt;/i&gt; was determined by weather conditions, especially by air temperature.

The effect of meteorological conditions on hazel (Corylus spp.) and alder (Alnus spp.) pollen concentration in the air of Szczecin

The aim of the study was to determine seasonal variations in concentrations of hazel and alder pollen count due to meteorological parameters. Measurements were performed using the volumetric method. The analysed meteorological parameters were the maximum temperature, relative humidity, rainfall and wind speed. The beginning and end of a season were established by the 95 % method. During seven years of study, the highest concentration of hazel pollen in the air was noted in 2003 (the total number was two - three times higher than in the other years), with the pollen season starting in most years in the beginning of January and lasting till the end of March or beginning of April. The highest concentration of alder pollen in the air was noted in 2003, similarly as hazel pollen. The pollen season started in the beginning of January (in 2003 and 2006 in the beginning of March) and lasted till the turn of the March and April. The highest pollen count of 674 grains×m&lt;sup&gt;-3&lt;/sup&gt; was observed in the end of March. A positive and statistically signifi cant correlation (Pearson's coeffi cient and multiple regression) was found between the hazel and alder pollen concentration and air temperature and wind speed. A negative correlation was found in case of the relative humidity. A lot of analysed correlations were signifi cant (significance level of p=0.05), although the percentage of explained variation (R&lt;sup&gt;2&lt;/sup&gt;) was very low. Besides the individual rhythm of pollination, the meteorological conditions are the most important factors (mainly air temperature and wind speed) influencing the analysed pollen concentration in the air.

Seasonal variation of concentration and size distribution of total aerosols, chloride, nitrate, and sulfate in urban air

Seasonal variation of concentration and size distribution of total aerosols, chloride, nitrate, and sulfate in urban air

Diurnal and seasonal variation of mercury species at coastal-suburban, urban, and rural sites in the southeastern United States

Observations for the 2005–2008 time period from three Southeastern Aerosol Research and Characterization (SEARCH) air quality monitoring sites are examined for diurnal and seasonal variation in concentrations of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle bound mercury (HgP < 2.5 μm). The sites are located at 1) a suburban-coastal location near Pensacola, Florida (OLF), 2) an urban location in Birmingham, Alabama (BHM), and 3) a rural location west-northwest of Atlanta, Georgia (YRK). Average concentrations of GEM at both OLF and YRK are 1.35 ng m−3, whereas at BHM it is 2.12 ng m−3. All sites show increase in GEM concentration during the morning hours (0.023 and 0.011 ng m−3hr−1 at OLF and YRK between 6 and 10 AM, 0.038 ng m−3hr−1 at BHM between 5 and 10 AM) due to downward mixing of higher concentrations from the residual layer, after which OLF and YRK show negligible variation compared to decrease in concentration at BHM (2.3–1.9 ng m−3 from 10 AM to 6 PM). All sites show seasonal variation of GEM with enhanced concentrations found in winter and spring. Average GOM concentrations are 4.26, 8.55, and 78.2 pg m−3 at OLF, YRK, and BHM, respectively. Seasonally, GOM values are enhanced during fall and spring. All sites undergo a sinusoidal daytime variation of GOM that peaks in the afternoon, while BHM additionally exhibits an early morning enhancement likely caused by vertical mixing. The average HgP concentrations at OLF, YRK, and BHM are 2.49, 4.43, and 39.5 pg m−3, respectively. At OLF, vertical mixing causes an early morning increase in HgP concentration followed by an afternoon decline during all seasons. A daytime increase in HgP is found at YRK for all seasons, while at BHM, nocturnal accumulation followed by a daytime decline is also found for most seasons except winter. In winter, concentrations increase due to vertical mixing in the morning and then decline as the boundary layer grows. Boundary layer processes appear to play an important role in the seasonal and diurnal variation of Hg species and further investigation utilizing a boundary layer process model is warranted.

Occurrence and air-seawater exchange of brominated flame retardants and Dechlorane Plus in the North Sea

The occurrence, spatial and seasonal concentration variations in air and seawater and the air–seawater exchange of polybrominated diphenyl ethers (PBDEs), alternate brominated flame retardants (BFRs) and Dechlorane Plus (DP) were studied in the German part of the North Sea in 2010. BDE–209 and DP were found to be the dominating compounds, both in the atmosphere and in seawater. Sum PBDEs (∑10PBDEs) ranged from 0.31 to 10.7 pg m−3 in the atmosphere and from not detected (n.d.) to 10.5 pg L−1 in seawater, respectively. DP ranged from 0.13 to 22.3 pg m−3 and from 0.10 to 17.7 pg L−1 in air and seawater, respectively. Besides, four other BFRs including hexabromobenzene (HBB) and pentabromobenzene (PBBz) were detected. Elevated atmospheric concentrations were observed in continentally influenced air masses while highest seawater concentrations were observed at sampling stations close to the coast influenced by riverine discharge. The ratio of the two DP stereoisomers both in air and water was found to be close to the technical mixture at high concentrations but changed at lower concentrations giving first evidence for the alteration within the aquatic environment. Both dry air-seawater gas exchange and dry deposition are input pathways of BFRs and DP in the North Sea besides riverine discharge.

Seasonal variation in concentrations of carbohydrates and lipids in two epiphytic lichens with contrasting, snow-depth related distribution on subarctic birch trees

The lichens Parmelia olivacea and Parmeliopsis ambigua are common epiphytes in subarctic forests in Europe. They differ in abundance and vertical distribution particularly on birch trees, and these differences relate to the level and duration of the winter snow cover. Parmeliopsis ambigua is covered much of the cold season on the lower trunk whereas P. olivacea occurs well above the snow surface. Periods over 6 months under snow have no apparent effect on P. ambigua thalli while much shorter snow cover has been demonstrated to kill P. olivacea. It was hypothesized that the contrasting distributions are due to differences in growth rates and in size and quality of non-structural carbon stores in their tissues affecting their endurance to extended periods of dark respiration. To test these hypotheses, growth measurements were performed on both species and their thalli were sampled for chemical analyses. The results show that the mean annual margin extension growth of P. olivacea thalli was significantly higher than that of P. ambigua, i.e. 1.1 mm and 0.5 mm, respectively. The average non-structural carbohydrate concentration in the two species did not differ, but the annual concentration of storage lipids (triacylglycerol) in P. ambigua was four times higher than that in P. olivacea, despite a shorter growing season and lower rate of photosynthesis. The proportion of polyunsaturated fatty acids in structural (polar) lipids was high in both species, i.e. 77% in P. olivacea and 64% in P. ambigua, which appears to enable both species to withstand low ambient thallus temperatures. The higher concentration of storage lipids in P. ambigua allows survival in environments where P. olivacea would respire to death, e.g. under a prolonged snow cover. Parmeliopsis ambigua avoids competition by establishing toward the base of the tree trunk, where P. olivacea would not survive.

Effect of bacterial community dynamics on DOC seasonal changes in the north-western Mediterranean Sea

To better understand the seasonal variation in concentrations and accumulation of dissolved organic carbon (DOC) in north-western Mediterranean surface waters, we investigated changes in bacterial abundance, activity (production, BP; respiration, BR; growth efficiency, BGE) and DOC concentration at different depths during different periods: winter mixing, the phytoplankton bloom period and summer stratification. The highest DOC concentrations were observed during the stratified period, reaching 90 ± 10 µmol C L−1. During this period, DOC concentrations were negatively correlated with the BP and BGE values at 5 m and positively correlated with BR at 5 and 20 m. DOC concentrations were also negatively correlated with viral abundances at 5 and 20 m depths. Furthermore, viral abundances were negatively correlated with bacterial abundance, production and growth efficiency, thus suggesting a viral influence on bacterial DOC assimilation. Inorganic nutrient depletion observed during the summer period had no significant relationships with bacterial activity. Characterization of the bacterioplankton assemblages by denaturing gradient gel electrophoresis of 16S rRNA profiles revealed the existence of seasonal trends in phylogenetic identity of the bacterioplankton. During the summer stratification period, the relative intensity of specific phylotypes was correlated with DOC concentrations. Alphaproteobacteria and Synechococcus sp. phylotypes were highly correlated with chlorophyll a, BP and BGE.

Seasonal variation and sources of low molecular weight organic acids in precipitation in the rural area of Anshun

Low molecular weight (LMW) organic acids are important and ubiquitous chemical constituents in the atmosphere. A comprehensive study of the chemical composition of precipitation was carried out from June 2007 to June 2008 at a rural site in Anshun, in the west of Guizhou Province, China. During this period, 118 rainwater samples were collected and the main LMW carboxylic acids were determined using ion chromatography. The average pH of rainwater was 4.89 which is a typical acidic value. The most abundant carboxylic acids were formic acid (volume weight mean concentration: 8.77 μmol L−1) and acetic acid (6.90 μmol L−1), followed by oxalic acid (2.05 μmol L−1). The seasonal variation of concentrations and wet deposition fluxes of organic acids indicated that direct vegetation emissions were the main sources of the organic acids. Highest concentrations were observed in winter and were ascribed to the low winter rainfall and the contribution of other air pollution sources northeast of the study area. The ratio of formic and acetic acids in the precipitation ([F/A] T ) was proposed as an indicator of pollution source. This suggested that the pollution resulted from direct emissions from natural or anthropogenic sources. Comparison with acid precipitation in other urban and rural areas in Guizhou showed that there was a decreasing contribution of LMW organic acids to free acidity and all anions in rainwater from urban to remote rural areas. Consequently, it is necessary to control emissions of organic acids to reduce the frequency of acid rain, especially in rural and remote areas.