Phytoremediation capability of Typha latifolia L. to uptake sediment toxic elements in the largest coastal wetland of the Persian Gulf.

The present study evaluated the status of sediment toxicity and pollution, and the phytoremediation capability of Typha latifolia L. (TlL) within the largest coastal wetland in the southwest of Iran, the Shadegan International Wetland. In eight sampling sites, covering the entire wetland, the concentration of six toxic elements (As, Cr, Cu, Ni, Pb, and Zn) in the surface sediment, root, and stem of TlL were measured. The results indicated that mean concentrations of Cr, Cu, Pb, and Zn were found to be higher than those in the local background, which likely indicates anthropogenic sources of these elements. Due to the presence of a nearby landfill, the results of modified pollution index (MPI) and aggregate toxicity index (ATI) indicated a moderately-heavily polluted level and moderate to high toxic degree, respectively. However, the medium-low level of toxicity toward living of organisms (21 % probability) was detected based on the assessment of the Sediment Quality Guidelines (SGQ). The results of our study indicate that the root and stem tissues of TlL are capable of acting as an indicator of Cu/Pb/Zn and Zn pollution in sediment, respectively. Considering the potential of phytoremediation, TlL represented both phytostabilization and phytoextraction capabilities for Pb and Zn and a significant increase was observed in the phytoremediation capability by increasing the distance from the landfill area. According to the results of the metal accumulation index (MAI) and comprehensive bioconcentration index (CBCI), TlL grown in the study area showed an acceptable performance in the accumulation of multiple toxic elements compared to that in Turkey, India, and Poland. Overall, TlL is a good candidate for the phytoremediation of sediments contaminated by Pb and Zn.

Human-induced pollution and toxicity of river sediment by potentially toxic elements (PTEs) and accumulation in a paddy soil-rice system: A comprehensive watershed-scale assessment.

This study aimed to assess pollution by potentially toxic elements (PTEs) in the Zarjoub and Goharroud river basins in northern Iran. Due to exposure to various types of pollution sources, these rivers are two of the most polluted rivers in Iran. They also play an important role in irrigation of paddy fields in the study area, increasing concerns about the contamination of rice grains by PTEs. Hence, we analyzed the concentrations of eight PTEs (i.e., As, Co, Cr, Cu, Mn, Ni, Pb, and Zn) at ten channel bed sediment sampling sites in each river, fifteen samples of paddy soils and fifteen co-located rice samples in the relevant watersheds. Results of the index-based assessment indicate moderate to heavy pollution and moderate toxicity for sediments in the Goharroud River, while both pollution and toxicity of the Zarjoub River sediment were characterized as moderate. Paddy soils in the watersheds were found to be moderate to heavily polluted by PTEs, but the values of the rice bioconcentration factor (RBCF) indicated intermediate absorption for Cu, Zn, and Mn, and weak and very weak absorption for Pb/Ni and As/Co/Cr, respectively. The concentration of Zn, Cu, Pb, and Cr was negatively correlated to the corresponding values of RBCF, highlighting the ability of rice grains to control bioaccumulation and regulate concentrations. Industrial/agricultural effluents, municipal wastewater, leachate of solid waste, traffic-related pollution, and weathering of parent materials were found to be responsible for pollution of the Zarjoub and Goharroud watersheds by PTEs. Mn, Cu, and Pb in rice grains might be responsible for non-carcinogenic diseases. Although weak absorption was observed for As and Cr in rice grains, the concentrations of these elements in rice grains indicate a high level of cancer risk if ingested. This study provides insights to control the pollution of sediment, paddy soils, and rice.

COVID-19 and urban rivers: Effects of lockdown period on surface water pollution and quality- A case study of the Zarjoub River, north of Iran.

Due to the spreading of the coronavirus (COVID-19) in Iran, restrictions and lockdown were announced to control the infection. In order to determine the effects of the lockdown period on the status of the water quality and pollution, the concentrations of Al, As, Ba, Cr, Cu, Mo, Ni, Pb, Se, and Zn, together with Na+, Mg2+, Ca2+ and electrical conductivity (EC), were measured in the Zarjoub River, north of Iran, in both pre-lockdown and post-lockdown periods. The results indicated that water pollution and associated human health risk reduced by an average of 30% and 39%, respectively, during the lockdown period. In addition, the multi-purpose water quality index also improved by an average of 34%. However, the water salinity and alkalinity increased during the lockdown period due to the increase of municipal wastewater and the use of disinfectants. The major sources of pollution were identified as weathering, municipal wastewater, industrial and agricultural effluents, solid waste, and vehicular pollution. PCA-MLR receptor model showed that the contribution of mixed sources of weathering and municipal wastewater in water pollution increased from 23 to 50% during the lockdown period. However, the contribution of mixed sources of industrial effluents and solid wastes reduced from 64 to 45%. Likewise, the contribution of traffic-related sources exhibited a reduction from 13% in the pre-lockdown period to 5% together with agricultural effluent in the post-lockdown period. Overall, although the lockdown period resulted in positive impacts on diminishing the level of water pollution caused by industrial and vehicular contaminants, the increase of municipal waste and wastewater is a negative consequence of the lockdown period.

Groundwater geochemistry, quality, and pollution of the largest lake basin in the Middle East: Comparison of PMF and PCA-MLR receptor models and application of the source-oriented HHRA approach.

We evaluated groundwater quality, pollution, and its effects on human health in the eastern part of the Lake Urmia basin, the largest lake in the Middle East. Although groundwater quality is suitable for drinking and irrigation purposes, an index-based approach quantifying heavy metal pollution revealed that most sampling sites exhibited moderate to high pollution levels in the northern and southern regions. The positive matrix factorization (PMF) and principal component analysis-multi linear regression (PCA-MLR) receptor models suggest that the main contributors to the observed groundwater pollution, expressed as percentages by model, were: lake water infiltration and dissolution of minerals and fertilizers (46% and 63%), infiltration of leachates from solid wastes (29% and 15%), mixing with industrial-municipal wastewaters (18% and 13%), and vehicular emissions (7% and 9%). The PMF model indicated better correlations between observed and predicted concentrations (R2 = 0.96) than the PCA-MLR (R2 = 0.89). Our results from the human health risk assessments (HHRA) highlight non-carcinogenic and carcinogenic risks for Pb and Cr, respectively. Also, the PMF-based assessment of human health risk indicated that wastewaters and solid waste leachates are responsible for the cancer risk from Cr for children.

Potentially toxic elements contamination in surface sediment and indigenous aquatic macrophytes of the Bahmanshir River, Iran: Appraisal of phytoremediation capability.

To determine the status and sources of contamination and phytoremediation capability of Typha latifolia L. in the Bahmanshir River of Iran, the concentration of eight potentially toxic elements (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in sediment and plant tissues from ten sampling sites were measured. Mean concentrations of Cd, Cr, Cu, Pb, and Zn in the sediment exceeded those of local background. PCA-MLR receptor analysis suggested that the sediment contamination was due to municipal wastewater/vehicular pollution and weathering/industrial/agricultural activities, with contributions of 66% and 34%, respectively. Average enrichment factor (EF) and modified hazard quotient (mHQ) for Pb and Cu were categorized as moderate. Modified pollution index (MPI) and modified ecological risk index (MRI) values suggested moderate to heavy pollution and low ecological risk, respectively. The values of sediment quality guidelines (SQGs), ecological contamination index (ECI), contamination severity index (CSI), and toxic risk index (TRI) were all similar, reflecting low to moderate contamination and toxicity. Typha latifolia L. showed good phytostabilization capability for Cd, Cu, and Pb, and phytoextraction capacity for Zn. Using the metal accumulation index (MAI) and the comprehensive bioconcentration index (CBCI), Typha latifolia L. was shown to have acceptable performance in the accumulation of Cd, Cu, Pb, and Zn and thus, can be considered a good candidate for bioaccumulation of these elements in the study area. Overall, this study suggests that phytoremediation using Typha latifolia L. could be a practical method for uptake and remove of potentially toxic elements from aquatic environments.

Spatial distribution and risk assessment of agricultural soil pollution by hazardous elements in a transboundary river basin.

The present study aimed to evaluate the sources of pollution and the potential human and ecological risks of hazardous elements (HEs) in 40 hotspot sites of the agricultural soil around the Arvand River, Iran. The mean concentrations of As, Cd, Co, Cr, Ni, Pb, Zn, and Hg were measured to be 7.2, 0.8, 14.0, 67.9, 69.5, 63.0, 296, and 0.66 (mg kg-1), respectively. With the exception of Ni, the mean concentrations of all the elements were found to be higher than those in the background. The spatial distribution of HEs in the study area indicated an increasing trend of contamination from the north to the south. Pb, Zn, and Hg were the most enriched elements, resulting in a high pollution load. Moreover, the agricultural soil of the study area was threatened by a very high ecological risk due to the contribution of Hg, Cd, and Pb. Multivariate statistical analyses determined that the pollution sources are specified by the oil refinery emissions and effluents, irrigation with polluted water, fertilizers, dust storms, and airport emissions. The carcinogenic risk of HEs in both adults and children revealed an acceptable level; however, children faced a great chance of non-carcinogenic risk. The results provide a scientific basis for monitoring HEs and managing health risks via effective methods in the agricultural areas of the Arvand River basin.

Decreased mitochondrial bioenergetics and calcium buffering capacity in the basal ganglia correlates with motor deficits in a nonhuman primate model of aging.

Altered mitochondrial function in the basal ganglia has been hypothesized to underlie cellular senescence and promote age-related motor decline. We tested this hypothesis in a nonhuman primate model of human aging. Six young (6-8 years old) and 6 aged (20-25 years old) female Rhesus monkeys (Macaca mulatta) were behaviorally characterized from standardized video records. Additionally, we measured mitochondrial bioenergetics along with calcium buffering capacity in the substantia nigra and putamen (PUT) from both age groups. Our results demonstrate that the aged animals had significantly reduced locomotor activity and movement speed compared with younger animals. Moreover, aged monkeys had significantly reduced ATP synthesis capacity (in substantia nigra and PUT), reduced pyruvate dehydrogenase activity (in PUT), and reduced calcium buffering capacity (in PUT) compared with younger animals. Furthermore, this age-related decline in mitochondrial function in the basal ganglia correlated with decline in motor function. Overall, our results suggest that drug therapies designed to enhance altered mitochondrial function may help improve motor deficits in the elderly.

Distribution, elimination, and biopersistence to 90 days of a systemically introduced 30 nm ceria-engineered nanomaterial in rats.

Nanoceria is used as a catalyst in diesel fuel, as an abrasive in printed circuit manufacture, and is being pursued as an antioxidant therapeutic. Our objective is to extend previous findings showing that there were no reductions of cerium in organs of the mononuclear phagocyte (reticuloendothelial) system up to 30 days after a single nanoscale ceria administration. An ~5% aqueous dispersion of citrate-stabilized 30 nm ceria, synthesized and characterized in-house, or vehicle, was iv infused into rats terminated 1, 7, 30, or 90 days later. Cageside observations were obtained daily, body weight weekly. Daily urinary and fecal cerium outputs were quantified for 2 weeks. Nine organs were weighed and samples collected from 14 tissues/organs/systems, blood and cerebrospinal fluid for cerium determination. Histology and oxidative stress were assessed. Less than 1% of the nanoceria was excreted in the first 2 weeks, 98% in feces. Body weight gain was initially impaired. Spleen weight was significantly increased in some ceria-treated groups, associated with abnormalities. Ceria was primarily retained in the spleen, liver, and bone marrow. There was little decrease of ceria in any tissue over the 90 days. Granulomas were observed in the liver. Time-dependent oxidative stress changes were seen in the liver and spleen. Nanoscale ceria was persistently retained by organs of the mononuclear phagocyte system, associated with adverse changes. The results support concern about the long-term fate and adverse effects of inert nanoscale metal oxides that distribute throughout the body, are persistently retained, and produce adverse changes.