Microplastic particles in sediments and waters, south of Caspian Sea : frequency, distribution, characteristics, and chemical composition

This study assesses the occurrence of microplastics (MPs) in coastal and sea surface sediment, as well as water samples, collected from the coastal region of the southern Caspian Sea, Mazandaran province, Iran. A total of 32 sediment and 10 water samples were studied. The mean concentration of MPs was 15 units kg-1 in the sediments and 710 units m-3 in the coastal water. Fibers constituted by far the dominant MPs in both media, accounting for 97% of the MPs in both sediment and water samples. The MPs were mainly black in color. The dominant size of MP particles in sediment samples was between 250 and 500 µm, while the fraction >1000 µm dominated in the water samples. Polyethylene terephthalate (PET), polystyrene (PS), and nylon (NYL) were the main polymers and/or copolymers composing MPs in both sediment and water samples. The MP particles had a relatively smooth surface morphology, although signs of weathering were observed. The number of MP particles in sediment and water samples showed a general decrease from west to east in the study area. This may be reflecting the spreading of MP loading from the outlets of Sefidrud, Tonekabon, Chalus, the major rivers entering the Caspian Sea just west of the study area, and the overall decrease in the spatial distribution of touristic and fishery activity. The main sources of MP particles could be local emissions from a large number of domestic wastewater effluents and urban surface runoff due to high population density, and industrial and fishing activities in this region. This study indicated that MP particles, based on their characteristics and chemical composition, are circulated between coastal waters, and shore and sea surface sediments of the Caspian Sea, leading to their uneven distribution in the different depths. To the best of our knowledge, this is the first work studying the distribution of MP particles in sea surface sediments and also the most comprehensive on MPs in shoreline sediments and coastal waters in the southern Caspian Se

Occurrence of trace elements (TEs) in seafood from the North Persian Gulf : implications for human health

In the present study the concentrations of 12 trace elements (TEs): As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn were quantified in muscle and, where possible, liver tissues, of six commercially important marine species including fish (Euryglossa orientalis, Sardinella longiceps, Carcharhinus dussumieri), crustacean (Portunus armatus, Thenu orientalis) and mollusc (Sepia pharanois) collected from the North Persian Gulf. Arsenic, copper, iron, and zinc were observed to be the most dominant TEs in muscle and liver tissues of all the species. In comparing with the maximum permissible limits (MPL) set by international organizations for seafood including FAO (1983), EC (2007), FAO/WHO (2007), and USEPA (2011), the mean concentrations of As, Cd in all the species and Mn, Zn, and Hg in some species exceeded their MPL limits. The relationships between TEs concentration and biometric indices (body length and weight) varied markedly among the TEs within both species and tissues. Estimated daily intake (EDI) results in comparison with values of the tolerable daily intake (TDI) confirmed that consumption of T. orientalis, C. dussumieri and S. pharanois from the sampled locations exceed their maximum values for As, Cd, Hg, and Se established for children

Salt Effects on Formation and Stability of Colloidal Gas Aphrons Produced by Anionic and Zwitterionic Surfactants in Xanthan Gum Solution

This work is devoted to the influence of NaCl salt concentration on the formation and stability of colloidal gas aphrons (CGA) produced by the anionic surfactant sodium dodecyl sulfate (SDS) and zwitterionic surfactant coco amido propyl betaine (CAPB) in the presence of xanthan gum (XG) as a stabilizer. Dynamic surface tension measurements as well as volume and half-life time of the produced foams are considered for stability analysis. A sharp decrease of the half-life time and volume of the CGAs at NaCl concentrations larger than 20,000 ppm was observed, which was attributed to the precipitation of SDS in the solution. The mentioned SDS precipitation altered the dynamic surface tension behavior, dilational surface elasticity, and turbidity of the solution. The main reason for the precipitation of SDS is the increased Krafft point caused by the addition of salt. However, for the zwitterionic surfactant CAPB, the effects of added NaCl on the interfacial properties required for CGAs production was negligible due to the simultaneous effects on the cationic and anionic head groups in the CAPB leading to negligible changes in the net repulsion forces. Yet, an overall reduction in the half-life time of CGAs with increasing salt concentration, even when we have no precipitation, was observed for both surfactants, which could be explained by the reduction in the ability of XG to increase the viscosity with increasing salt concentration

Mineralogical Composition of Urinary Stones and Their Frequency in Patients: Relationship to Gender and Age

This investigation reports the mineralogy and possible pathological significance of urinary stones removed from patients in Fars province, Iran. X-ray diffraction (XRD), scanning electron microscopy (SEM) and polarizing microscope (PM) techniques were used to investigate the mineralogical compositions of urinary stones. The identified mineral components include whewellite, weddellite, hydroxyapatite, uricite and cystine. These techniques revealed that the whewellite and uricite were the most common mineral phases. Platy-like/monoclinic whewellite, prismatic/monoclinic uric acid and hexagonal cystine crystals were revealed by SEM. Biominerals (calcium carbonate) and quartz were also identified in PM images. Of the variables determining the type of precipitated minerals, the effects of pH on depositional conditions proved to be the most apparent parameter, as shown by occurrences and relationships among the studied minerals. Our results revealed the importance of detailed knowledge of mineralogical composition in assessing the effects of age and sex. The highest incidence of urinary stones was observed in the 40–60 age group. Calcium oxalate and uric acid stones are more frequent in men than women. Finally, the study concluded that knowledge of the mineralogical composition of urinary stones is important as it helps the scientific community to explain the chemistry and the etiology of the calculi in the urinary system

Trace element concentration in soils and plants in the vicinity of Miduk copper mine

Introduction High concentrations of metals are usually encountered in surface soil and vegetation in areas affected by mining activity (Liu et al., 2006). Different distribution of elements in chemical fractions result in different bioavailability; therefore knowledge of the total content of an element in soil is not a sufficient criterion to estimate the environmental implications of trace metal presence (Maiz et al., 2000). Sequential extraction analysis gives information on the element distribution among different phases of soil. Several schemes of sequential extraction are used for the determination of commonly distinguished metal species, which are in general: (1) easily exchangeable or water soluble; (2) specifically sorbed; e.g., by carbonates or phosphates; (3) organically bound; (4) occluded by Fe-Mn oxides and hydroxides; and (5) structurally bound in minerals or residual (Kabata-Pendias and Mukherjee, 2007). The main objectives of this study are: (1) to describe the distribution pattern of elements in rocks and soils of the Miduk area; (2) to assess the fractionation of elements in soil and the mining impact on the mobility of trace elements; (3) to investigate the uptake of analyzed elements by selected indigenous plant species. Materials and Methods In this study, 32 soil samples at two depths (0-5 cm and 15-20 cm), were analyzed for total concentration of 45 elements. In order to assess the possible bioaccumulation of the elements, the roots and the overground parts of 3 plant species (Astragalus-Fabaceae, Acanthophyllum -Caryophyllaceae, Artemisia -Asteraceae) were also collected and analyzed. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The Tessier et al. method (Tessier et al., 1979) was chosen for sequential extraction of 6 subsoil samples. Correlation analysis was used to examine the relationship between the analyzed elements in soil. The plant’s ability to take up chemical elements from growth media was evaluated by calculating transfer factor (TF) (Kabata-Pendias and Pendias, 2001). Results Topsoil samples displayed higher mean levels of Mo, Cd, Se, Fe, As, Pb, Cu and Zn compared to subsoil samples. Generally, Cu is accumulated in the upper few centimeters of the soil, but in deeper soil layers it has a tendency to be absorbed by organic compounds and oxy-hydroxides of Mn and Fe (Kabata-Pendias and Mukherjee, 2007). The total mean concentrations of Cu (201.19 mg kg-1), As (26.90 mg kg-1) and Pb (83.87 mg kg-1) are higher than those recorded for natural uncontaminated soils worldwide (Kabata-Pendias and Pendias, 2001). The strongest correlation (higher than 0.80) is observed in samples taken from two depths for Zn and Pb, Zn and Cd, Cr and Ni, and Ni and Mg. The geochemical behavior of Pb and Zn is known to be similar in most natural processes (Reinmann and Caritat, 1998). Element concentrations in the roots and leaves of plants differ considerably between the three analyzed plant genuses. Element concentrations in Astragalus genus are higher than Artemisia and Acanthophyllum, expect for Pb and Cd, which displayed the highest concentration in Artemisia. Astragalus is the most contaminated species among the collected plants. The lowest concentration for all elements is found in the leaves of Acanthophyllum species. The results probably demonstrate the influence of the plant’s genetics on element uptake. The following decreasing order shows median transfer factor in plants with little differences between the three plant species: Cd>Mo>Cu>As>Mg>Mn>Pb>Fe>Ni>Ag>Co>Cr. The results of sequential extraction analysis showed that more than 54.01% of extracted Cu is bound to Fe-Mn oxides fraction, followed by the organic matter and residual fractions. The hydrous oxides of Fe and Mn control Cu fixation in soil (Davies, 1997). Arsenic and chromium mostly remained in the residue of the sequential extraction process. The high Pb concentration in the residual and Fe-Mn oxides fractions indicated that the soil may be considered unpolluted by lead. Discussion Among the measured elements, soil contamination is mostly observed for Cu, Pb, and As. The soil of the study area is also significantly polluted by lead, especially in the old mining areas. The high concentrations of Mg, Se, and Cd extracted into the first three fractions of sequential extraction showed that the metals could be easily mobilized upon changes in ionic strength or decrease in pH and redox potential. Artemisia leaves are significantly contaminated by Cu. Arsenic and copper also accumulate in Astragalus leaves. The consumption of Artemisia and Astragalus leaves can constitute an exposure risk, especially for small domestic animals. Miduk inhabitants consume Artemisia leaves for treatment of digestive upsets. It is suggested to keep this area inaccessible to domestic animals and preferably to collect plants from distant areas. Obviously, systematic monitoring during mining should be instituted, and continuous environmental surveys should be performed to prevent future pollution problems. Acknowledgement The authors would like to thank the Research and Development Department of Sarcheshmeh Copper Complex and the Shiraz University research committee for making this study possible. References Davies B. E., 1997. Heavy Metal Contaminated Soils in an Old Industrial Area of Wales, Great Britain: Source identification through statistical data interpretation. Water, Air, and Soil Pollution, 94 (1-2): 85–98. Kabata-Pendias, A. and Mukherjee, A.B., 2007. Trace Elements from Soil to Human. Springer, Berlin, 550 pp. Kabata-Pendias, A. and Pendias H., 2001. Trace Elements in Soils and Plants. CRC Press, Florida, 413 pp. Liu, J., Zhong, X.M., Liang, Y.P., Luo, Y.P., Zhu, Y.N. and Zhang, X.H., 2006. Fractionation of Heavy Metals in Paddy Soils Contaminated by Electroplating Wastewater. Journal of Agro-Environment Science, 25(2): 398-401. Maiz, I., Arambarri, R. and Garcia, E.M., 2000. Evaluation of Heavy Metal Availability in Polluted Soils by two Sequential Extraction Procedures using Factor Analysis. Environmental Pollution, 110(1): 3- 9. Reinmann, C. and Caritat, P.D., 1998. Chemical Elements in the Environment. Factsheets for the Geochemist and Environmental Scientist. Springer, Verlag, 596 pp. Tessier, A., Campbell, P.G.C. and Bison, M., 1979. Sequential Extraction Procedure for the Speciation of Particulate Metals. Analytical chemistry, 51(7): 844-851. <br

Spatial distribution, source apportionment, and ecological risk assessment of elements (PTEs, REEs, and ENs) in the surface soil of shiraz city (Iran) under different land-use types

In this study, 100 samples were collected from the topsoil of different land-use types (urban, industrial and agricultural) in Shiraz. The content of 26 elements was analyzed. CF, EF, Igeo, NPI, and PLI indices were used to evaluate soil pollution. Ecological risk assessment of metals was calculated by using Er and RI indexes. PCA analysis and the PMF model were used to determine the source of metals in soil. Also, the spatial distribution of metals and risk index were plotted using inverse distance weighting (IDW) with ArcGIS software (10.3). The metal concentrations in the soil ranged from 0.2067 ± 0.0946 (Ag) to 85,673.50 ± 4689.27 (Ca) mg kg−1. The results show that all elements' Concentration in soils was lower than the DOE level. The mean concentration of All rare earth elements (REEs) was lower than WSA and ECM values. Hotspot points pollution of some metals such as Pb, Cd, and Ni are located in high-traffic parts of the urban area. Otherwise, hot spot points of As pollution are located in industrial sample points. Results of indexes show that Sb in urban and agricultural soils have highe mean values of CF (6.75 and 6.85) and Iegeo (2.17 and 2.13), respectively. In industrial soils, S has highe mean values of CF (14.95), EF (100.26), and Igeo (2.95). The PLI index shows that REEs (PLI 1). The mean Er, value shows that Sb (127.33) and Cd (104) have significant risk among metals. PCA and PMF models show that The main sources of elements in shiraz soil are vehicularly emitted, fertilizer use, sewage irrigation, atmospheric deposition, and parent material. Generally, results show that Most of the study area has considerable risk, especially concerning PTEs. So, it is recommended to pay more attention to the issue of traffic in the urban environment in to improve the state of the urban area

An Estimation of Wave Attenuation Factor in Ultrasonic Assisted Gravity Drainage Process

It has been proved that ultrasonic energy can considerably increase the amount of oil recovery in an immiscible displacement process. Although many studies have been performed on investigating the roles of ultrasonic waves, based on the best of our knowledge, little attention has been paid to evaluate wave attenuation parameter, which is an important parameter in the determination of the energy delivered to the porous medium. In this study, free fall gravity drainage process is investigated in a glass bead porous medium. Kerosene and Dorud crude oil are used as the wetting phases and air is used as the non-wetting phase. A piston-like displacement model with considering constant capillary pressure and applying Corey type approximation for relative permeabilities of both wetting and nonwetting phases is applied. A pressure term is considered to describe the presence of ultrasonic waves and the attenuation factor of ultrasonic waves is calculated by evaluating the value of external pressure applied to enhance the flow using the history matching of the data in the presence and absence of ultrasonic waves. The results introduce the attenuation factor as an important parameter in the process of ultrasonic assisted gravity drainage. The results show that only a low percentage of the ultrasonic energy (5.8% for Dorud crude oil and 3.3% for kerosene) is delivered to the flow of the fluid; however, a high increase in oil recovery enhancement (15% for Dorud crude oil and 12% for Kerosene) is observed in the experiments. This proves that the ultrasonic waves, even when the contribution is not substantial, can be a significantly efficient method for flow enhancement