Potential ecological risk assessment of heavy metals (trace elements) in coastal soils of southwest Iran.

Heavy metal pollution has become one of the most important threats that can endanger the health of animals, the environment, and humans. The present study was performed to investigate the potential ecological risk (PER) of heavy metals [zinc (Zn), copper (Cu), cobalt (Co), molybdenum (Mo), manganese (Mn), and selenium (Se)] in the coastal soils of southwest Iran in 2019. The samples were collected from six soil sites and three depth intervals (0-15, 15-30, and 30-45 cm) among bare and vegetated coastal soils. The soil samples to study the soil properties (soil grain size, pH, EC, and soil organic carbon) and metal contamination were taken from soil (36 samples), water (6 samples), and plants (24 samples). The soil ecological risk (ER), the pollution load index (PLI), contamination degree (Cdeg), modified contamination degree (mCdeg) for heavy metal contamination in the soil, and enrichment factor (EF index) indicate the origin of metals entering the environment, and hence these parameters were investigated. The results of this study showed that the levels of Zn, Cu, Co, Mn, Se, and Mo were in the range of low-risk contaminants in this region. According to the results of the study, the risk index (RI) for metals was in the range of 1.296-3.845, which is much lower than 150, and therefore the ecological risk potential calculated in this study was in the low-risk category for toxic elements. Based on the results, it was found that agricultural, industrial, and human activities played an effective role in the accumulation of Zn, Cu, Co, Se, and Mo in the soil. In addition, the main source of Mn metal is believed to be natural due to geological activities in the region.

The effects of citalopram, SB-334867 and orexin-1, alone or in various combinations, on the anxiogenic-like effects of REM sleep deprivation in male mice.

Sleep deprivation may induce anxiety. On the other hand, anxiety disorders elicit main changes in the quality of sleep. Moreover, orexin and citalopram play a role in the modulation of insomnia and mood diseases. Thus, we planned preclinical research to evaluate the effect of combinations of orexin agents and citalopram on anxiety behavior in rapid eye movement (REM) sleep-deprived mice. For drug intracerebroventricular (i.c.v.) infusion, the guide cannula was surgically implanted in the left lateral ventricle of mice. REM sleep deprivation was conducted via water tank apparatus for 24 h. The anxiety behavior of mice was evaluated using the elevated plus maze (EPM). Our results revealed that REM sleep deprivation reduced the percentage of open arm time (%OAT) and the percentage of the open arm entries (%OAE) but not closed arm entries (locomotor activity) in the EPM test, presenting an anxiogenic response ( P < 0.05). We found a sub-threshold dose of SB-334867, orexin-1 receptor antagonist, and orexin-1 which did not alter anxiety reaction in the REM sleep-deprived mice ( P > 0.05). Intraperitoneal (i.p.) injections of citalopram (5 and 10 mg/kg) increased both %OAT and %OAE ( P < 0.001) representing an anxiolytic effect, but not locomotor activity in the REM sleep-deprived mice. Interestingly, co-treatment of citalopram (1, 5 and 10 mg/kg; i.p.) and SB-334867 (0.1 µg/mouse; i.c.v.) potentiated the anxiolytic effect in the REM sleep-deprived mice. On the other hand, co-treatment of different dosages of citalopram along with a sub-threshold dose of orexin-1 did not alter %OAT, %OAE, and locomotor activity in the REM sleep-deprived mice. We found a synergistic anxiolytic effect of citalopram and SB-334867 in the REM sleep-deprived mice. These results suggested an interaction between citalopram and SB-334867 to prevent anxiogenic behavior in the REM sleep-deprived mice.

Synergistic antidepressant effects of citalopram and SB-334867 in the REM sleep-deprived mice: Possible role of BDNF.

This study was done to evaluate the effect of co-treatment of orexin agents along with citalopram on the modulation of depression-like behavior and the expression of BDNF in the prefrontal cortex (PFC) of sleep-deprived male mice. A sleep deprivation model was performed in which rapid eye movement (REM) sleep was completely prohibited, and non-REM sleep was intensely reduced for 24 h. For drug microinjection, the guide cannula was surgically fixed in the left lateral ventricle of mice. Furthermore, we used the open-field test (OFT), forced swim test (FST), tail suspension test (TST), and splash test for recording depression-like behavior as well as Real-Time PCR amplification for assessing the expression of BDNF in the PFC of REM sleep-deprived mice. Our results revealed that REM sleep deprivation did not change locomotor activity while increased depressive-like behavior in FST, TST, and splash tests. However, the expression of BDNF was decreased in the PFC. Intraperitoneally (i.p.) administration of citalopram induced antidepressant effect in the normal and REM sleep-deprived mice. Moreover, intracerebroventricular (i.c.v.) microinjection of a non-effective dose of SB-334867, an orexin antagonist, potentiated the antidepressant-like effect of citalopram. On the other hand, a non-significant dosage of orexin-1 reversed the antidepressant effect of citalopram in the normal and REM sleep-deprived animals. Furthermore, our results showed that injection of citalopram alone or with SB-334867 increased the mRNA expression level of BDNF in the PFC of REM sleep-deprived mice. These data suggest that REM sleep deprivation interferes with the neural systems underlying the depression-like process and supports a likely interaction of the orexin system with citalopram on the modulation of depression-like behavior in REM sleep-deprived mice.

Possible involvement of the CA1 GABAergic system on harmaline induced memory consolidation deficit.

Activation of the GABAB receptors inhibit learning and memory processes. The current research was designed to examine the role of dorsal hippocampal (CA1) GABAB receptors on harmaline induced memory consolidation deficit in mice. For this purpose, the effects induced by the GABAB antagonist phaclofen and the GABAB agonist baclofen on memory consolidation were assessed by using the step-down inhibitory avoidance task. Furthermore, the possible involvement of harmaline on GABAB receptor's effects was also assessed through using the same behavioral procedure. In a first dose response experiments, post-training intra-CA1 injections of phaclofen did not change while baclofen (0.1µg/mouse) impaired animals' performance in this task, suggesting a modulation of storage of information. Moreover, Post-training intra-peritoneal (i.p.) infusion of harmaline (2 and 5mg/kg) also decreased memory consolidation. Interestingly, phaclofen at the sub-threshold dose (0.001µg/mouse, intra-CA1), successfully antagonized the deficits on memory consolidation induced by the highest doses of harmaline (2 and 4mg/kg, i.p.). On the other hand, non significant dose of baclofenc (0.001µg/mouse, intra-CA1) potentiated impairment of memory consolidation induced by harmaline (2mg/kg, i.p.). In addition in all experiments, locomotor activity did not alter significantly. These results indicate a) that the CA1 GABAB receptors are involved in memory consolidation b) that harmaline interact with the CA1 GABAB receptors in modulation of memory consolidation.

Conductance studies on complex formation between c-methylcalix[4]resorcinarene and titanium (III) in acetonitrile-H2O binary solutions.

Calixresorcinarenes have proved to be unique molecules for molecular recognition via hydrogen bonding, hydrophobic and ionic interactions with suitable substrates such as cations. The study of the interactions involved in the complexation of different cations with calixresorcinarenes in solvent mixtures is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This article summarizes different aspects of the complexes of the Ti(3+) metal cation with c-methylcalix[4]resorcinarene (CMCR) as studied by conductometry in acetonitrile (AN)-water (H2O) binary mixtures at different temperatures. Conductance data show that the metal cation/ligand (ML) stoichiometry of the complexes in solution is 1:1 in all cases. Non-linear behaviour was observed for the variation of logKf of the complexes vs. the composition of the binary solvent mixtures. Selectivity of CMCR for the Ti(3+) cation is sensitive to solvent composition; in some cases and at certain compositions of the mixed solvent systems, the selectivity order is changed. Values of thermodynamic parameters (ΔH(c)(0), ΔS(c)(0)) for formation of the CMCR-Ti(3+) complexes in AN-H2O binary systems were obtained from the temperature dependence of stability constants, and the results show that the thermodynamics of complexation reactions are affected by the nature and composition of the mixed solvents.

Limit of detection and limit of quantification development procedures for organochlorine pesticides analysis in water and sediment matrices.

BACKGROUND: Reliable values for method validity of organochlorine pesticides determination were investigated, in water by solid phase extraction and in sediment by Soxhlet extraction, followed by gas chromatography equipped with an electron capture detector. Organochlorine pesticides are categorized as Persistent Organic Pollutants. Hence, critical decisions to control exposure to these chemicals in the environment are based on their levels in different media; it is important to find valid qualitative and quantitative results for these components. In analytical chemistry, internal quality procedures are applied to produce valid logical results. RESULT: In this study, 18 organochlorine pesticides were targeted for analysis and determination in water and river sediment. Experiments based on signal-to-noise ratio, calibration curve slope and laboratory fortified blank methods were conducted to determine the limits of qualification and quantification. The data were compared with each other. The limitation values, following Laboratory Fortified Blank, showed significant differences in the signal-to-noise ratio and calibration curve slope methods, which are assumed in the results for the sample concentration factor to be 1,000 times in water and 10 times in sediment matrices. The method detection limit values were found to be between 0.001 and 0.005 µg/L (mean of 0.002 ± 0.001) and 0.001 and 0.005 µg/g (mean of 0.001 ± 0.001). The quantification limits were found to be between 0.002 and 0.016 µg/L (mean of 0.006 ± 0.004) and 0.003 and 0.017 µg/g (mean of 0.005 ± 0.003 µg/L) for water and sediment, respectively, based on the laboratory fortified blank method. Because of different slopes in the calibration methods, it was also found that the limitation values for some components from the internal standard were higher than from external standard calibration, because in the latter a factor for injection efficiency is applied for calibration. CONCLUSION: Technically, there are differentiations between detection limits for quality and quantity from component to component, resulting from noise, response factors of instruments and matrix interference. However, the calculation method is the cause of differentiation for each component of the different methods. The results show that for no matter what component, the relationship between these levels in different methods is approximately: Signal to Noise : Calibration Slope = 1:10. Therefore, due to different methods to determine LOD and LOQ, the values will be different. In the current study, laboratory fortified blank is the best method, with lower limitation values for Soxhlet and solid phase extraction of OCPs from sediment and water, respectively.

Distribution and fate of HCH isomers and DDT metabolites in a tropical environment-case study Cameron Highlands-Malaysia.

BACKGROUND: The serious impact effects of persistent organic pollutants such as organochlorine pesticides, especially dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) have been causing widespread concern, despite effective control on their manufacturing, agricultural and vector practices. In that, in addition to the previous global limitations on DDTs usage, α-HCH, ß-HCH and lindane have also became an on-going topic of global relevance based on the latest Stockholm Convention list on 10th of May 2009. Concentrations of dichlorodiphenyltrichloroethane family (DDTs) and hexachlorocyclohexane isomers (HCHs) were determined by GC-ECD in Cameron Highlands, the main vegetables and flowers farming area in Malaysia as an agricultural tropical environment. A total of 112 surface water and sediment samples at eight points were collected along the main rivers in the area namely Telom and Bertam in the dry and wet seasons of 2011. RESULTS: Total concentration of HCH isomers ranged from not detected to 25.03 ng/L in the water (mean of 5.55 ±6.0 ng/L), while, it ranged from 0.002 to 59.17 ng/g (mean of 8.06±9.39 ng/g) in the sediment. Total concentration of DDT and its metabolites in the water samples varied from not detected to 8.0 ng/L (mean of 0.90±1.66 ng/g), whereas, it was in the range of 0.025 to 23.24 ng/g (mean of 2.55±4.0 ng/g) in the surface sediment samples. The ratio of HCHs and DDTs composition indicated an obvious historical usage and new inputs of these pesticides. Among alpha, beta, gamma and delta isomers of HCH, gamma was the most dominant component in the sediment and water as well. Some seasonal variations in the level of selected pesticides were noted. CONCLUSIONS: The results illustrate distribution, behaviour and fate of HCHs, and DDTs have closely connected with topological and meteorological properties of the area beyond their chemical characterizations. The features of environmental circumstances exceed one or more of these characters in importance than the other. Although the results show that the situation is better than 1998, the impact of persistent agrochemicals such as lindane and 4,4'DDE are revealed in a key tropical area of Malaysia.