Characteristics of oxidant precursor emissions from anthropogenic sources in the United States

Hydrocarbons (HC) and nitrogen oxides (NO_x) have been identified as the most important precursor pollutants for oxidant formation in the atmosphere. These pollutants are emitted both from natural and anthropogenic sources; however, these two types of sources are generally geographically separated. Anthropogenic emissions are dominant in and around urban centers, where the majority of severe oxidant problems occur. Based on data gathered by the MAP3S/RAINE emissions inventory project, anthropogenic emissions of HC in the conterminous United States were 24.8 million metric tons in 1979. HC emissions were predominantly from area sources, the transportation sector being the largest contributor with 39.8% of the total. State-by-state breakdowns are also included. Based on analyses by other emissions inventory projects, the nonreactive fraction of the emissions from the transportation sector is less than 20% by weight. The highest proportion of HC emissions occur at low altitudes (0–50 m range) in high population density areas. Anthropogenic emissions of NO_x were 23.7 million metric tons in 1979; 50.8% were from point sources. The transportation sector and the electric utilities sector account for 37.1% and 30.9% of the NO_x emissions, respectively. The NO₂ fraction of the emissions from the transportation and electric utilities sectors is less than 10% by weight, based on NO/NO₂ speciation data from two other emissions inventories. Highest rates of NO_x emissions occur in high population density areas and are released at low altitude (0–50 m); three areas of high electric generating capacity were found to have high release altitudes.     

Dechlorane Plus in serum from e-waste recycling workers: Influence of gender and potential isomer-specific metabolism

Dechlorane Plus (DP) and its dechlorinated product, anti-Cl₁₁-DP, were measured in serum of 70 occupationally exposed workers in an e-waste recycling region and 13 residents of an urban area in South China. The DP levels were significantly higher in the workers (22–2200 ng/g with median of 150 ng/g lipid) than in the urban residents (2.7–91 ng/g with median of 4.6 ng/g lipid). The DP concentrations in females were found to be associated with their age but such relation was not found for males. Significant differences in DP levels and DP isomer composition were found between genders. The females had remarkably higher DP levels and f_anti values (fraction of anti-DP to total DPs) in serum than the males. Anti-Cl₁₁-DP was significantly correlated with anti-DP for both genders but with different slope of regression line. The ratios of anti-Cl₁₁-DP to anti-DP (mean of 0.017) in males were significantly higher than those (mean of 0.010) in females. Combining with the lower f_anti values in males, it is likely that males have higher metabolic potential for DPs than females which resulted in the lower DP loading in serum. However, the different patterns of selective uptake and/or excretion of different compounds between genders cannot be eliminated as a possible reason for the observed gender differences. This study is the first to report on the gender difference in DP accumulation in human, and its mechanism is worth further investigation.     

Comparison of distribution coefficients for americium and curium: Effects of pH and naturally occurring colloids

Distribution coefficients (K_D) were measured by a batch technique for sorption of americium-243 and curium-244 to Lake Michigan sediment from four different natural surface waters. The dependences of K_D values on pH and on the concentrations of naturally occurring colloidal organic carbon (COC) were studied. The comparison of K_D values showed that, while changes in pH and in COC concentrations cause significant changes in sorption for both americium and curium, neither variable causes a significant difference in sorption between these two elements.     

(210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil

Activity profiles of excess ²¹⁰Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na₂O, K₂O, CaO, MgO, Al₂O₃, P₂O₅, Fe₂O₃ and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm⁻² yr⁻¹ were obtained, and are compatible with the results of others studies. The ²¹⁰Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile.     

Comparison of indoor and outdoor air quality at two staff quarters in Hong Kong

The indoor and outdoor air quality of two staff quarters of Hong Kong Polytechnic University at Tsim Sha Tsui East (TSTE) and Shatin (ST) were investigated. The air sampling was carried out in winter for about two months starting from January to February of 1996. Fifteen flats from each staff quarter were randomly selected for indoor/outdoor air pollutant measurements. The pollutants measured were NO_x, NO, NO₂, SO₂, CO, and O₃. The variations of pollutant concentrations between indoor and outdoor air were investigated on weekday mornings, weekday evenings, weekend mornings, and weekend evenings. All indoor/outdoor pollutant concentrations measured did not exceed the ASHRAE/NAAQS standard. The carbon monoxide concentrations indoors were systemically higher than those outdoors at the TSTE and the ST quarters, both on weekdays and Sunday, which indicates there are CO sources indoors. Except for CO, the indoor levels of other pollutants (NO_x, NO, NO₂, SO₂, and O₃) are lower than those outdoors. There was a significant correlation (P < 0.05) between indoor and outdoor concentrations for SO₂ and O₃ at both the TSTE and the ST quarters. Except for O₃, the mean concentrations of all the pollutants in the TSTE quarters, both indoor and outdoor, were higher than that of the ST quarters in all sampling periods. All indoor and outdoor O₃ levels were lower at the TSTE quarters than those at the ST quarters. The O₃ ratios of TSTE/ST were 0.72 outdoor and 0.79 indoor. This can be explained by the NO titration reaction through NO conversion to NO₂.     

Brominated flame retardants in the indoor environment — Comparative study of indoor contamination from three countries

Concentrations of more than 20 brominated flame retardants (FRs), including polybrominated diphenyl ethers (PBDEs) and emerging FRs, were measured in air, dust and window wipes from 63 homes in Canada, the Czech Republic and the United States in the spring and summer of 2013. Among the PBDEs, the highest concentrations were generally BDE-209 in all three matrices, followed by Penta-BDEs. Among alternative FRs, EHTBB and BEHTBP were detected at the highest concentrations. DBDPE was also a major alternative FR detected in dust and air. Bromobenzenes were detected at lower levels than PBDEs and other alternative FRs; among the bromobenzenes, HBB and PBEB were the most abundant compounds. In general, FR levels were highest in the US and lowest in the Czech Republic — a geographic trend that reflects the flame retardants' market. No statistically significant differences were detected between bedroom and living room FR concentrations in the same house (n = 10), suggesting that sources of FRs are widespread indoors and mixing between rooms. The concentrations of FRs in air, dust, and window film were significantly correlated, especially for PBDEs. We found a significant relationship between the concentrations in dust and window film and in the gas phase for FRs with log K_OA values < 14, suggesting that equilibrium was reached for these but not compounds with log K_OA values > 14. This hypothesis was confirmed by a large discrepancy between values predicted using a partitioning model and the measured values for FRs with log K_OA values > 14.     

Characteristics of parasitic infection in the least cisco, Coregonus sardinella valenciennes, 1848, in the Ural tributaries of the lower Ob

Data on the parasite fauna of the least cisco, Coregonus sardinella Valenciennes, 1848 in Ural tributaries of the Ob downstream of the city of Salekhard have been obtained for the first time. The formation patterns of the parasite fauna in this species and the rate (prevalence and intensity) of infection by Ichthyocotylurus erraticus (Odening, 1969), a parasite specific to coregonids, have been revealed. Infection of the least cisco with six parasite species (out of the 12 species found) occurs as the fish feed on zooplankton and benthic organisms. The dominant parasites are trematode larvae of the genera Ichthyocotylurus and, in some years, Diplostomum; this composition of dominants is evidence that the least cisco fattens up mainly in shallow areas. All sexually mature fish of this species were found to be infected by I. erraticus, but the average intensity of infection was rather low: the abundance index of the parasite did not exceed 40 ind. per fish. Analysis of the distribution of I. erraticus metacercariae in the least cisco shows that the relationship in the host-parasite system is stable and the parasite has no pathogenic effect on individuals of older age classes.     

The effect of pollutants (heavy metals and diesel fuel) on the respiratory activity of constructozems (artificial soils)

Young (1 month old) and mature (2 years old) constructozems (artificial soils) were supplemented with individual heavy metal salts or diesel fuel at different concentrations. The polluted and control constructozem variants were incubated and sampled at different time points to determine microbial biomass carbon (C_mic) and microbial respiration (MR). These parameters were found to be almost twice higher in the young than in the mature constructozem, with all pollutants causing an increase in C_mic, MR, and MR/C_mic = qCO₂ values. The pollutant type had an effect on MR and qCO₂ variances, and the time of exposure, on C_mic. The qCO₂ value showed a strong positive correlation with pollutant concentrations, allowing this parameter to be regarded as a suitable indicator of urban environmental pollution.     

Using sequential extraction techniques to assess the partitioning of plutonium and neptunium-237 from multiple sources in sediments from the Ob River (Siberia)

Sequential extraction techniques have been developed to assess partitioning of anthropogenic radionuclides (²⁴⁰Pu, ²³⁹Pu, and ²³⁷Np), originating from a variety of sources, as identified by using bulk sediment isotopic composition. Sediments were leached sequentially with a series of six chemical treatments designed to approximate different environmental processes that may occur or to selectively extract trace metals contained in different solid phases of the sediments (i.e., exchangeable, reducible, carbonate, organic, acid leachable, and refractory). Results indicate the majority of Pu and Np is similarly distributed within many of the extracted fractions, with the largest percentage (66–97%) of both elements being observed in sediments treated with buffered citrate dithionite (CDB), which targets easily reduced constituents such as Mn and Fe hydrous oxides. While these results do indicate an association of Pu and Np with redox sensitive elements, the environmental implications are unclear given that the CDB treatment is more extreme than naturally occurring conditions. Minor amounts of Np partition differently from Pu in sediments. The NH₄-acetate treatment, which is designed to liberate trace metals that are loosely adsorbed onto the surfaces of sedimentary materials such as hydrated iron oxides and humic substances, or present at exchangeable sites in clay minerals, mobilized ∼12% of the total Np while Pu levels were below detection. The H₂O₂ treatment, which is designed to liberate trace metals bound to organic matter, mobilized ∼8 and ∼1% of Np and Pu, respectively. These results indicate that a minor portion of the total Np may be affected by environmental conditions that have little or no effect on Pu. Between 7 and 24% of the Pu was observed in treatments designed to liberate Pu and Np that are tightly bound to lithogenic phases or refractory silicates. The ²⁴⁰Pu/²³⁹Pu observed in accessible and refractory fractions ranged between 0.11 and 0.18. With the exception of one sample, the ²⁴⁰Pu/²³⁹Pu isotope ratios measured in the refractory fractions are essentially identical having a mean ratio value of 0.123 ± 0.001 (1σ). The ²⁴⁰Pu/²³⁹Pu ratios provide isotopic evidence that suggests a portion of non-fallout contamination has a refractory nature. The presence of similarly low ²⁴⁰Pu/²³⁹Pu ratios in refractory fractions of sediments from the Ob and Irtysh Rivers suggests the existence of a source of refractory Pu which is consistent with refractory “hot particles” derived from surface tests at the Semipalitinsk test site.     

Cesium accumulation by aquatic organisms at different trophic levels following an experimental release into a small reservoir

The rates of accumulation and subsequent loss of stable cesium (¹³³Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of ¹³³Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg⁻¹ d⁻¹ dry mass) and a loss rate parameter k (d⁻¹) were estimated for each organism using time-series measurements of ¹³³Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (C_r). The maximum ¹³³Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The C_r based on dry mass for plankton and C. punctipennis were 1220 L kg⁻¹ and 5570 L kg⁻¹, respectively, and were less than the C_r of 8630 L kg⁻¹ for periphyton and 47,700 L kg⁻¹ for H. trivolvis. Although the C_r differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the C_r for the mostly nonpiscivorous L. macrochirus of 22,600 L kg⁻¹ was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg⁻¹. Although the C_r for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum ¹³³Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides.     

Suspended particulate matter in dwellings — the impact of tobacco smoking

The indoor concentration of suspended particulate matter (SPM) was measured in forty-four retrofitted and tight dwellings, which had electric cooking and were central heated and where the basic ventilation rate in median amounted 0.23 air changes per hour as measured with a tracer dilution method. The indoor concentration of SPM was in median 230 μg/m³ with a strong correlation to the tobacco consumption (r_s=0.716), but with no correlation to the frequency of airing or the basic ventilation rate. Tobacco smoking seems to be the main indoor source of SPM in contemporary dwellings. The importance of these findings is underlined by epidemiologic studies on passive smoking and health. Air quality standards for the ambient air are based on certain risk groups such as infants, children, persons with chronic obstructive lung disorders, and indoor air standards should be based on the same concepts of health protection.     

Short-term effects of air pollution on respiratory morbidity at Rio de Janeiro — PART I: Air Pollution Assessment

Exposure to air pollution has been related with the most varied adverse health outcomes. This study aims to assess the impact of air pollution on the emergency hospitalization for respiratory disease in Rio de Janeiro, Brazil. The study was divided in two parts: Part I specifically addressing the air pollution assessment and Part II addressing the health assessment. Accordingly, this Part I aims to: i) evaluate the concentrations of PM₁₀, SO₂ and CO at two sites in Rio de Janeiro and compare them; ii) analyse the concentrations observed according to the national and international standards; and iii) analyse the air pollutants behaviour, namely, annually, seasonally, daily and considering weekdays/weekends variations. The pollutant concentrations were measured at two different sites in Rio de Janeiro and the analysis was performed for the period between September 2000 and December 2005. Results showed that PM₁₀ concentrations in Rio de Janeiro exceeded the daily and annual standards imposed by the European Union, the Brazilian legislation and WHO guidelines. Regarding SO₂ and CO, concentrations were, generally, below both European and Brazilian standards. Nevertheless, considering WHO guidelines, SO₂ threshold for daily concentrations (20 μg m^− 3) was exceeded around 150 times. Behaviour assessment showed that the influence of traffic is a major factor affecting the air pollution in Rio de Janeiro.Considering the results achieved and the proven health effects of air pollution, strategies should be defined for its reduction, particularly concerning particulate matter, and consequently contribute to the protection of public health.     

ANN-based mapping of monthly reference crop evapotranspiration by using altitude, latitude and longitude data in Fars province, Iran

The main goal of this study was to evaluate the different feed-forward back-propagation artificial neural networks’ (ANNs) potential to estimate and interpolate the reference crop evapotranspiration (ET₀) in Fars province of Iran. ET₀ was calculated using the FAO-56 Penman–Monteith method over 24 synoptic stations. Then, altitude, latitude, longitude and the month’s number as inputs and the monthly ET₀ as output (target) were used to train the ANNs. In addition, the three-layered ANNs optimized with different training algorithms including gradient descent back-propagation (gd), gradient descent with adaptive learning rate back-propagation (gda), gradient descent with momentum and adaptive learning rate back-propagation (gdx) and scaled conjugate gradient back-propagation (scg). The results indicated that scg algorithm with architecture (4 2 1) had more satisfactory results with the RMSE and R correlation coefficient equal to 18.538 mm and 0.967 in validation phase, respectively. Based on the mentioned architecture of scg algorithm, and input data form different parts of Fars province and surrounding areas, monthly ET₀ maps were produced and annual one achieved by summation of monthly maps. The maps particularly annual one showed that highest values of ET₀ could be found in the southern and especially southeastern regions, while the lowest values of ET₀ could be seen in the northern parts. Contribution of geographic and topographic variables improved the accuracy and spatial details of the resulting maps. It is interesting to note that the fundamental capability of this model is the usage of just a few parameters for ET₀ mapping. Since ET₀ is a key parameter in water demand planning, therefore, the derived maps could be useful and applicable for many purposes mainly irrigation scheduling in Fars province, Iran.     

Endocrine activity of persistent organic pollutants accumulated in human silicone implants — Dosing in vitro assays by partitioning from silicone

Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control exposure of the adrenal cells by equilibrium partitioning. (3) Hormone production of the adrenal cells was measured as toxicity endpoint. 4-Nonylphenol was used for method development, and the new dosing method was compared to conventional solvent-dosing. The two dosing modes yielded similar dose-dependent hormonal responses of H295R cells. However, with the partitioning-controlled freely dissolved concentrations (C_free) as dose metrics, dose–response curves were left-shifted by two orders of magnitude relative to spiked concentrations. Partitioning-controlled dosing of POPs resulted in up to 2-fold increases in progestagen and corticosteroid levels at C_free of individual POPs in or below the femtomolar range. Silicone acted not only as source of the POPs but also as a sorption sink for lipophilic hormones, stimulating the cellular hormone production. Methodologically, the study showed that silicone can be used as reference partitioning phase to transfer in vivo exposure in humans (silicone implants) to in vitro assays (partition-controlled dosing). The main finding was that POPs at the levels at which they are found in humans can interfere with steroidogenesis in a human adrenocortical cell line.     

Seasonal variation in outdoor,indoor, and personal air pollution exposures of women using wood stoves in the Tibetan Plateau: Baseline assessment for an energy intervention study

Cooking and heating with coal and biomass is the main source of household air pollution in China and a leading contributor to disease burden. As part of a baseline assessment for a household energy intervention program, we enrolled 205 adult women cooking with biomass fuels in Sichuan, China and measured their 48-h personal exposure to fine particulate matter (PM_2.5) and carbon monoxide (CO) in winter and summer. We also measured the indoor 48-h PM_2.5 concentrations in their homes and conducted outdoor PM_2.5 measurements during 101 (74) days in summer (winter). Indoor concentrations of CO and nitrogen oxides (NO, NO₂) were measured over 48-h in a subset of ~ 80 homes. Women's geometric mean 48-h exposure to PM_2.5 was 80 μg/m³ (95% CI: 74, 87) in summer and twice as high in winter (169 μg/m³ (95% CI: 150, 190), with similar seasonal trends for indoor PM_2.5 concentrations (winter: 252 μg/m³; 95% CI: 215, 295; summer: 101 μg/m³; 95% CI: 91, 112). We found a moderately strong relationship between indoor PM_2.5 and CO (r = 0.60, 95% CI: 0.46, 0.72), and a weak correlation between personal PM_2.5 and CO (r = 0.41, 95% CI: − 0.02, 0.71). NO₂/NO ratios were higher in summer (range: 0.01 to 0.68) than in winter (range: 0 to 0.11), suggesting outdoor formation of NO₂ via reaction of NO with ozone is a more important source of NO₂ than biomass combustion indoors. The predictors of women's personal exposure to PM_2.5 differed by season. In winter, our results show that primary heating with a low-polluting fuel (i.e., electric stove or wood-charcoal) and more frequent kitchen ventilation could reduce personal PM_2.5 exposures. In summer, primary use of a gaseous fuel or electricity for cooking and reducing exposure to outdoor PM_2.5 would likely have the greatest impacts on personal PM_2.5 exposure.     

DNA hypomethylation and its mediation in the effects of fine particulate air pollution on cardiovascular biomarkers: A randomized crossover trial

BackgroundShort-term exposure to fine particulate matter (PM_2.5) air pollution has been associated with altered DNA methylation in observational studies, but it remains unclear whether this change mediates the effects on cardiovascular biomarkers.ObjectiveTo examine the impact of ambient PM_2.5 on gene-specific DNA methylation and its potential mediation in the acute effects of PM_2.5 on cardiovascular biomarkers.MethodsWe designed a randomized, double-blind crossover trial using true or sham air purifiers for 48 h among 35 healthy college students in Shanghai, China, in 2014. We measured blood global methylation estimated in long interspersed nucleotide element-1 (LINE‑1) and Alu repetitive elements, methylation in ten specific genes, and ten cardiovascular biomarkers. We used linear mixed-effect models to examine the associations between PM_2.5 and methylation. We also performed causal mediation analyses to evaluate the potential mediation of methylation in the associations between PM_2.5 and biomarkers.ResultsAir purification increased DNA methylation in repetitive elements and all candidate genes. An IQR increase (64 μg/m³) in PM_2.5 was significantly associated with reduction of methylation in LINE-1 (1.44%), one pro-inflammatory gene (CD40LG, 9.13%), two pro-coagulant genes (F3, 15.20%; SERPINE1, 3.69%), and two pro-vasoconstriction genes (ACE, 4.64%; EDN1, 9.74%). There was a significant mediated effect (17.82%, P = 0.03) of PM_2.5 on sCD40L protein through CD40LG hypomethylation. Hypomethylation in other candidate genes generally showed positive but non-significant mediation.ConclusionsThis intervention study provided robust human evidence that ambient PM_2.5 could induce rapid decreases in DNA methylation and consequently partly mediate its effects on cardiovascular biomarkers.     

Influence of fertilizing on the Cs soil–plant transfer in a spruce forest of Southern Germany

Fertilization with 2.5 t/ha limestone: (83% CaCO₃, 8% MgO, 6% K₂O, 3% P₂O₅) reduces the ¹³⁷Cs transfer from spruce forest soil into plants like fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus) by a factor of 2–5 during at least 11 years as measured by the aggregated transfer factor T_ag. In 1997 and 2006 these results were confirmed by additional measurements of the ¹³⁷Cs transfer factor TF, related to the root zone (O_h horizon), which were explained by the selective sorption of ¹³⁷Cs in the root zone by measurements of the Radiocaesium Interception Potential (RIP) in fertilized (RIP > 179 meq/kg) and non-fertilized soils (RIP < 74 meq/kg).     

Interpreting soil CO<Subscript>2</Subscript> transport and production in oasis cotton field,central Asia

In order to explore soil profile CO₂ transport and production, values of vertical soil profile CO₂ concentration, moisture and temperature were measured continuously during whole cotton growing season in oasis cotton field of Aksu National Experimental Station of Oasis Farmland Ecosystem, central Asia. Simultaneously, soil CO₂ efflux was measured by chamber system to assess the deducing result by Fick’s first law. In our experiment, soil CO₂ effluxes were determined by two related intimately methods. Soil CO₂ releasing at 0–20 cm depth was calculated by gas transport equation and was found to be closely related to soil CO₂ efflux. However, mean values of soil CO₂ production at 0–20 cm depth were less than those of soil CO₂ efflux during the whole cotton growing season. Moreover, there were some negative values of CO₂ production at 0–20 cm depth found during the experimental period.     

Genetic differentiation of black saxaul, Haloxylon aphyllum (Chenopodiaceae), along a soil salinity gradient in the Kyzylkum Desert

Populations of Haloxylon àphyllum in the Kyzylkum Desert have been found to be markedly deficient in heterozygotes at a medium level of genetic diversity (P ₉₅ = 0.56, A = 1.67, H _o = 0.14, H _e = 0.28). Spatial genetic differentiation of these populations have been revealed along a soil salinity gradient (from 0 to 0.5 mmol Na⁺/g), with their genetic diversity reaching a maximum (H _o = 0.21?C0.25, H _e = 0.25?C0.27) in areas with a moderate salinity level (0.05?C0.1 mmol Na⁺/g). Locus Got-2 can serve as a marker of this differentiation (Fst_Got-2 = 0.4).