High Concentrations Of Cadmium Research Articles

INTENSITY OF HEAVY METAL AND ARSENIC ACCUMULATION IN MEDICINAL PLANTS OF SYNANTHROPIC FLORA IN VORONEZH REGION

The aim of this study is to examine the peculiarities of the accumulation of the most dangerous heavy metals and arsenic in medicinal plant raw material of the synanthropic flora in the Voronezh region.
 Materials and Methods. The study was carried out by atomic absorption spectrometry. The author studied the accumulation of heavy metals (lead, mercury, cadmium, nickel, copper, zinc, cobalt, chromium) and arsenic in 10 types of medicinal plant raw materials harvested in 51 locations (Voronezh region), which differ in terms of anthropogenic impact.
 Results. The highest level of lead consentration was noted in Taraxacum officinale F.H. Wigg, and Arctium lappa L. roots, Рolygonum aviculare L. and Plantago major L. leaves. Mercury concentration in all studied samples was rather low. A bit higher mercury concentration was noted in Plantago major L and Urtica dioica L. leaves, and Artemisia absinthium L. High cadmium concentration was found in Taraxacum officinale F.H. Wigg and Arctium lappa L. roots, Plantago major L. leaves, Artemisia absinthium L. and Leonurus quinquelobatus Gilib. Arsenic accumulated intensively in Plantago major L. leaves, Arctium lappa L. roots, Artemisia absinthium L. and Achillea millefolium L. Nickel accumulated intensively in Plantago major L. and Urtica dioica L. leaves, Рolygonum aviculare L. and Leonurus quinquelobatus Gilib. Zinc accumulated mainly in the roots and herbs themselves. Having analyzed the accumulation coefficients of heavy metals and arsenic for all studied medicinal plant raw materials, we organized the heavy metals and arsenic in the decreasing order: zinc > copper > cadmium > cobalt > nickel > arsenic > chromium > lead > mercury.

STUDY OF PECULIARITIES OF ACCUMULATION OF HEAVY METALS AND ARSENIC IN MEDICINAL PLANT RAW MATERIALS OF SYNANTHROPIC FLORA OF VORONEZH REGION

Fundamental regional ecological and pharmacognostic studies of the quality of LRS were carried out on the example of the Voronezh region, the peculiarities of the accumulation of the most dangerous heavy metals and arsenic in LRS growing both in traditional places of harvesting and in anthropogenic disturbed ecotopes were studied. The highest concentrations of lead are observed in the roots of medicinal dandelion and common burdock, bird's mountain grass, plantain leaves. The mercury content in all the studied samples is generally low, does not exceed 10% of the MAC. Higher concentrations of cadmium were found in herbs of bitter wormwood and five-lobed motherwort, roots of common burdock and medicinal dandelion, leaves of large plantain. The arsenic content in a number of samples of bitter wormwood grass and common yarrow, big plantain leaves, common burdock roots exceeded the MAC. Nickel is intensively accumulated by the leaves of the plantain of the great and nettle of the dioecious, by the herbs of the motherwort of the five-lobed and the mountain of the bird. The most active concentrators of chromium and cobalt are the roots; chromium also actively accumulates in the leaves of the plants under study. High accumulation of copper was distinguished by herbs. Zinc accumulates to the greatest extent in the studied roots and herbs of plants. Clars of the studied elements in plants of the synanthropic flora of the Voronezh region have been identified, which, along with the MAC, is an important ecological and geochemical indicator for LRS, reflecting the combined impact of technogenic and natural processes occurring in a certain time slice.

Transcriptomic Changes Induced by Low and High Concentrations of Heavy Metal Exposure in Ulva pertusa.

The impact of sewage and wastewater pollution on marine ecosystems is of increasing concern due to the rapid accumulation of heavy metals in seaweeds inhabiting near-shore environments. Seaweeds can be severely damaged by heavy metals throughout their life cycles. Although the physiological and ecological effects of heavy metal exposure have been studied, there is limited research on their molecular responses. Ulva pertusa is a prevalent seaweed species in South Korea and is ecologically significant in coastal ecosystems. We utilized high-throughput RNA sequencing to analyze changes in the transcriptome profiles of U. pertusa under low concentrations of heavy metals (MPS) and high concentrations of copper (MPS-Cu) and cadmium (MPS-Cd). Differential gene expression analysis revealed that 53 (control vs. MPS), 27 (MPS vs. MPS-Cd), and 725 (MPS vs. MPS-Cu) genes were expressed differentially. Differentially expressed genes identified in our study included those with protective roles against oxidative stress and those involved in metal transport to the vacuole. Furthermore, exposure to heavy metal stress had a negative impact on the photosynthetic apparatus structural proteins of U. pertusa, resulting in photosynthetic inhibition. Moreover, exposure to high concentrations of copper resulted in the activation of carbon-related metabolism. These findings contribute to our understanding of the molecular mechanisms underlying heavy metal toxicity in U. pertusa.

The impact of human activities on the mangrove forests of the Qeshm Island, Iran

This article investigates the human impact on the mangrove forest in the Qeshm Geopark on the Qeshm Island in the south of Iran from 1986 to 2020. The area of mangrove forests increased by 14% from 5,131 hectares in 1986 to 5,472 hectares in 2000, and to 5,967 hectares in 2020. The mangrove forest is threatened by oil and gas facilities and a zinc smelter located on the island. The average concentration of nickel in sediment (97.2 μg/g) and in leaves (3.1 μg/g) was higher than the average concentration of vanadium in sediment (38.7 μg/g) and in leaves (0.5 μg/g). The results showed that the transfer coefficient of nickel and vanadium from root to leaf on the dry side of the Qeshm habitat (r = 0.597 and r = 0.516, respectively) was positively correlated with pH. Therefore, increasing the pH leads to an increased metal transfer from the root to the leaf, which endangers the mangrove habitat on the island. The mangrove forest in the vicinity of the zinc factory is threatened by high concentrations of lead (244.2 ppm), zinc (3172.8 ppm), arsenic, and cadmium found in the soil sample.

Environmental characterization of the estuarine zone of the Gulf of Montijo, province of Veraguas, Panama.

The study was performed in the Republic of Panama. Panama has a coastline of 2,988.3 km, of which 1,700.6 km corresponds to the Pacific coast. Most of the coast is flat, and several geomorphological features characterize the Panamanian coastal sector, such as the Gulf of Montijo, which is located towards the west of the Panamanian Pacific coast in the province of Veraguas. The Gulf is a remarkable ecosystem of mangroves well preserved and internationally recognized as a Ramsar area. It represents the buffer zone of Coiba Island (Coiba National Park). Sixteen sampling stations were established along the coast to analyze the vertical and spatial variability of physical and chemical parameters (temperature, salinity, dissolved oxygen, pH, and conductivity). The quality of unexposed marine sediment was evaluated in four samples from the western sector of the Gulf of Montijo. The marine sediment samples were collected with a Dietz-LaFond Snapper dredge, between 1.5 and 3.0 m depth. Physical and chemical observations and marine sediment sampling were carried out during high tide +4 to low tide +3, in negative syzygy phase tide. The analysis of the oceanographic conditions, especially the physical and chemical properties of the water along with the longitudinal profile, showed a conservative distribution increasing gradually towards the outer region in an approximately linear way due to the dilution and mixing processes, both in the surface layer and at the bottom, and a not very developed vertical gradient, with slight stratification. The results of heavy metal analyses in marine sediments report high cadmium concentrations along the west coast, with concentrations above the limit levels of the Canadian marine sediment quality guidelines. The study area requires continuous monitoring that is representative of seasonality (dry, intermediate, and rainy periods), including a more significant number of stations since it is evidence of an affectation of the environmental quality of the marine ecosystem due to possible anthropogenic activities.

A phytochemical study of the clover growing in Kuzbass

In addition to studying bioactive organic compounds in plants, it is increasingly important to determine the biological role of elements in plants growing in environmentally unfavorable areas. One of such regions in Russia is Kuzbass with its intensively developing chemical, metallurgical, and coal mining sectors. In this study, we assessed the plant materials of red clover (Trifolium pratense L.), alsike clover (Trifolium hybridum L.), and white clover (Trifolium repens L.) collected from their natural populations in Kuzbass.
 The qualitative and quantitative composition of heavy metals in the clover samples was determined voltammetrically. The contents of molybdenum and phosphorus were measured by the photocolorimetric method. Total nitrogen and protein were determined by the Kjeldahl method. Nickel, cobalt, and chromium were quantified by spectrophotometry.
 We analyzed the plant materials of the clover samples for heavy metals and found that the content of lead was the least in red clover and the highest in alsike clover. Copper varied in a larger range and was minimal in red clover compared to that in alsike and white clover. Zinc was found at higher concentrations of in white and red clover compared to that in alsike clover. The levels of cadmium exceeded the maximum permissible concentrations in all the clover samples. We also revealed that the clover samples contained different amounts of various amino acids, including arginine, valine, lysine, glycine, aspartic acid, and alanine.
 The plant materials of the clover species growing in Kuzbass can be used to improve the fertility of soil and nitrogen regime. However, the clover species should not be used in bulk feed for farm animals because of high concentrations of cadmium.

Assessment of the water quality of Bar-Bula Village well waters, Tafawa Balewa local government area, Bauchi State, Nigeria

There was a report of health challenges in our study area due to the consumption of water from wells sited in the community. The research was aimed at assessing the water quality parameters of the wells consumed by the villagers towards providing information on the possible health implication(s) of its consumption. Two sampling sites were selected, well 1 and well 2, which were hitherto the sole sources of water in the village. Physicochemical and microbiological quality parameters of samples were done in order to assess their conformance with the specification of Nigerian Standard for drinking water quality (NIS 554-2015). The results indicated that all physical water quality parameters have their mean concentration values below the maximum permissible limits, except colour which had total mean concentrations of 16.5 ± 0.65 TCU and 15.3 ± 0.65 TCU for well 1 and well 2 respectively, are relatively above the allowable unit range of 15 TCU (NIS-554-2015). The water quality assessment of wells also revealed high concentration of Cadmium (0.11 mg L-1 and 0.16 mg L-1, for well 1 and 2 respectively as against 0.003 mg L-1 specified by standard) and Magnesium (185 mg L-1 and 105 mg L-1 for well 1 and 2 respectively as against the maximum permissible limit of 20 mg L-1 specified by the standard). The microbial values of samples fall below the maximum permissible limit prescribed by the NIS standard. From the study, it was concluded that the presence of Cadmium in the well waters indicated that the water is unfit for consumption.

Association between cadmium and lead in active and passive cigarette smokers with bone mass: a retrospective study

Objective: Cigarette smoking harms all body systems, and its effects are primarily related to nicotine. However, the heavy metal content (mainly lead and cadmium) could add to nicotine's hazardous effects. Thus, the current study aimed to investigate the effect of cigarette smoking content of cadmium and lead on bone mineral density. Subjects and Methods: A retrospective analysis of data from active, passive, and non-smokers (every 70 subjects) was analyzed for patient demographics, laboratory investigation, serum cotinine (as a confirmatory marker of smoking, bone mineral density (BMD), blood and urinary levels of cadmium and lead). Results: Hemoglobin concentrations and red blood cell count were significantly reduced, while erythrocyte sedimentation rate and liver enzymes were significantly increased in active and passive smokers than non-smokers. Serum cadmium, lead, and cotinine were raised considerably in passive and active than non-smokers (0.47±0.05, 21.94±3.99, 5.35±0.90 in active, 0.32±0.09, 18.91±3.30, and 4.35±0.89 in passive, versus 0.09±0.06, 9.84±2.63, and 1.28±0.21 in the control group, successively). Bone mineral density was reduced in active and passive than non-smokers at the radial shaft, femoral neck, and spine. Cotinine was significantly and proportionately correlated with serum cadmium and lead and inversely correlated with bone mineral density. Furthermore, cadmium and lead were inversely correlated with BMD. Conclusion: Cigarettesmoke was associated with higher concentrations of cadmium, and lead may directly and indirectly share in the harmful effects of smoking on BMD. Keywords: Bone Mineral Density, Cotinine, Toxic Heavy Metals, Smoking

Assessment of the impacts of selected physicochemical and bacteriological parameters of wastewater (hospital effluents) from the University teaching hospital of Butare on the surrounding environment

Physicochemical and bacteriological properties are used to assess the quality of wastewater before discharge into the surrounding environment. This presented study was carried out to determine the contamination of effluents from the University Teaching Hospital of Butare. The results showed that the mean values such as 185 ± 7.07 mg/L, 1816 ± 2.83 mg/L, 335 ± 4.24 mg/L, 150.66 ± 2 mg/L, 269 ± 13 mg/L, and 4.19 ± 0.41 mg/L for EC, TDS, TSS, BOD, COD, and phosphates in the treated effluents, exceeded the permissible limits of WHO standards for wastewater discharge in the surrounding environment. In the case of heavy metals, a higher concentration of cadmium (0.29 ± 0.04 mg/L) was observed out of the allowed limit of WHO standard, whereas those for manganese (0.02 ± 0.01 mg/L) and zinc (0.16 ± 0.04 mg/L) were within the stipulated limit. Lead, iron, and chromium were not detected in CHUB treated effluents. Although CHUB treatment plant showed higher treatment efficiency, including 99.2%, 99.9%, and 92.9%, the recorded mean values showed higher abundance (7 × 106 Cfu/100 mL of TC, 6 × 105 Cfu/100 mL, and 5 × 107 Cfu/100 mL) of TC, FC, and E.coli in treated CHUB effluents. The proper treatment of CHUB effluent should be ensured before it is discharged into the environment.

The distribution of cadmium in soil and cacao beans in Peru

Peru is the eighth largest producer of cacao beans globally, but high cadmium contents are constraining access to international markets which have set upper thresholds for permitted concentrations in chocolate and derivatives. Preliminary data have suggested that high cadmium concentrations in cacao beans are restricted to specific regions in the country, but to date no reliable maps exist of expected cadmium concentrations in soils and cacao beans. Drawing on >2000 representative samples of cacao beans and soils we developed multiple national and regional random forest models to develop predictive maps of cadmium in soil and cacao beans across the area suitable for cacao cultivation. Our model projections show that elevated concentrations of cadmium in cacao soils and beans are largely restricted to the northern parts of the country in the departments of Tumbes, Piura, Amazonas and Loreto, as well as some very localized pockets in the central departments of Huánuco and San Martin. Unsurprisingly, soil cadmium was the by far most important predictor of bean cadmium. Aside from the south-eastern to north-western spatial trend of increasing cadmium values in soils and beans, the most important predictors of both variables in nation-wide models were geology, rainfall seasonality, soil pH and rainfall. At regional level, alluvial deposits and mining operations were also associated with higher cadmium levels in cacao beans. Based on our predictive map of cadmium in cacao beans we estimate that while at a national level <20 % of cacao farming households might be impacted by the cadmium regulations, in the most affected department of Piura this could be as high as 89 %.

The impact of cadmium stress on the ascorbate-glutathione pathway and ascorbate regeneration in tea plants

Ascorbic acid (AsA) and glutathione (GSH) contribute to defense responses under abiotic stresses. The present study explored the ascorbate-glutathione cycle and ascorbate regeneration under high concentration (30 mM) of cadmium in the tea plant (Camellia sinensis L.). The tea leaves showed speckles and necrosis from the third day of Cd treatment. The content of superoxide anion (O2.-) and hydrogen peroxide (H2O2) in the leaves were significantly higher until the seventh day after Cd treatment. The content of O2.- and H2O2 were the highest on the fifth day (212.7 and 153.6 % of the control, respectively). The AsA content increased (86.9 %) on the first day after Cd treatment and decreased significantly in the subsequent days, while GSH showed a reverse trend. The enzymatic activity assays showed that dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in AsA regeneration were downregulated considerably after Cd foliar application. In contrast, the activities of ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) increased on the first day and then declined. Reverse-transcription quantitative PCR showed upregulation of glutathione synthetase (CsGSHS), γ-glutamylcysteine synthetase (Csγ-ECS), and CsMDHAR of the AsA regeneration pathway and downregulation of CsDHAR and CsGR. The expressions of GDP-L-galactose phosphorylase (CsGGP), L-galactose-1-phosphate phosphatase (CsGPP), and L-galactono- 1,4-lactone dehydrogenase (CsGaILDH) of the L-galactose pathway were also downregulated. The results indicated that AsA, which can respond to Cd stress of plants by increasing antioxidant ability, was consumed to scavenge ROS; moreover, Cd stress inhibited AsA synthesis and regeneration, which made that tea plants suffering severe damage.

Biochar and nano-ferric oxide synergistically alleviate cadmium toxicity of muskmelon

Cadmium is toxic to plants. The accumulation of cadmium in edible plants such as muskmelon may affect the safe production of crops and result in human health problem. Thus effective measures are urgently needed for soil remediation. This work aims to investigate the effects of nano-ferric oxide and biochar alone or mixture on muskmelon under cadmium stress. The results of growth and physiological indexes showed that compared with the application of cadmium alone, the composite treatment (biochar and nano-ferric oxide) decreased malondialdehyde content by 59.12% and ascorbate peroxidase activity increased by 276.6%. Their addition can increase the stress resistance of plants. The results of soil analysis and cadmium content determination in plants showed that the composite treatment was beneficial to reduce the cadmium content in various parts of muskmelon. In the presence of high concentration of cadmium, the Target Hazard Quotient value of peel and flesh of muskmelon in the composite treatment was less than 1, which means the edible risk was greatly reduced. Furthermore, the addition of composite treatment increased the content of effective components; the contents of polyphenols, flavonoids, and saponins in the flesh of the compound treatment were increased by 99.73%, 143.07%, and 18.78% compared with the cadmium treatment. The results provide a technical reference for the further application of biochar combined with nano-ferric oxide in the field of soil heavy metal remediation, and provide a theoretical basis for further research on reducing the toxicity of cadmium to plants and improving the edible quality of crops.

Attapulgite amendment favors the utilization of high cadmium-contaminated soil for Erigeron breviscapus cultivation

A practical measure of soil pollution can effectively control the utilization of contaminated soil during the remediation process. In this study, Erigeron breviscapus was used as the experimental material. Soil polluted with high concentrations of cadmium (Cd) was used to study the effects of different doses of attapulgite (AP) (0, 10, 20, and 40 kg−1 for AP0, AP10, AP20, and AP40, respectively) on the yield and quality of E. breviscapus (as measured by scutellarin), as well as soil remediation. The results showed that the yield and scutellarin content of E. breviscapus decreased by 33.4% and 78.9%, respectively, in soil contaminated with high concentrations of Cd (AP0) compared with the control soil (without Cd added). Moreover, the yield increased by 48.0% and 10.6% in AP20 and AP40, respectively, compared with AP0, and the scutellarin content increased by a factor of 2.35–2.41 in AP10, AP20, and AP40. Compared with AP0, the soil Cd content decreased by 22.5–26.2% in AP10, AP20, and AP40 and the available Cd content and acid-extractable Cd fraction in the soil also decreased. The catalase, peroxidase, superoxide dismutase activities, chlorophyll, and Fe2+ content were increased in AP10, AP20, and AP40, leading to an increased yield and scutellarin content. Overall, AP20 had the best effect on the yield, quality of E. breviscapus, and soil remediation. This study provides a practical measure to consider for concurrent benefits of pollution remediation and utilization of Cd-contaminated soil.

Динаміка змін вмісту сполук кадмію та нітрат-іонів в екосистемі Прикарпаття

The purpose of the study was to form an algorithm for constant control of the content of cadmium and nitrate ions as an important component of environmental monitoring in the Ciscarpathia ecosystem. Materials and methods. The soils and drinking water of the plain, foothill and mountainous areas of the region were the object of research. The cadmium content was determined by atomic absorption spectrophotometry on a C-115 PC spectrophotometer. The concentration of nitrate ions in drinking water was determined potentiometrically using an ion-selective electrode. Results and discussion. The Ciscarpathia is a unique region of Ukraine with rich natural resources, diverse flora and fauna. At the same time, more than 500 industrial enterprises (more than 4% of the total area) of the chemical, energy, oil and gas, woodworking and other industries are located in the region. These enterprises cause a significant man-made load on all components of the natural environment. The ecological situation of the Ciscarpathian region is closely related to the state of soils and water resources. In this regard, it is appropriate to study and control the level of cadmium and nitrate compounds in the environment of the region. The study of the soils of the Carpathian region confirmed the growth of the cadmium toxic element, the content of which was by 1.3–1.5 times higher than the background indicators. It is determined that the level of nitrate ions in the drinking water of the plain zone exceeds the maximum permissible concentration by 1.5–2 times, and the physiological water completeness indicator – by 160–606 times; in the foothills and mountain zones the content of nitrates does not exceed the maximum permissible concentration, but it is by 35−253 times higher than the physiological water completeness indicator. The main stages of entry and accumulation of cadmium in the plant body have been analyzed. Conclusion. The results of our research made it possible to establish significant differences in the content of cadmium and nitrate ions in the soils and drinking water of different geographical zones of the Carpathian region. In particular, a significant number of the population living in the plains and foothills consumes water with a high content of nitrate ions and cadmium, which leads to an increase in the combined effect of these toxicants on living organisms. It is proposed to carry out constant monitoring of the level of toxicants in the ecosystem as an important component of environmental monitoring. The use of cultivated plants is recommended for cleaning the soil from cadmium contamination

Single and combined effects of microplastics and cadmium on the sea cucumber Apostichopus japonicus

Microplastic pollution of the ocean has received extensive attention as plastic pollution increases globally, but the potential ecological risks caused by microplastic interactions with trace metals still require further research. In this study, Apostichopus japonicus was used to explore the individual and combined toxicities of cadmium (Cd) and microplastics and their effects on growth, Cd tissue accumulation, digestive enzymes, and gut microbes. The body weight gain and specific growth rate of animals exposed to a combination of high concentrations of Cd and microplastics decreased. The addition of high concentrations of cadmium to the diet led to an increase in cadmium content in the respiratory tree, digestive tract and body wall. Amylase, lipase and trypsin decreased to different degrees in the group treated with high concentrations of Cd/microplastics. Firmicutes were significantly reduced across multiple treatment groups, with the order Lactobacillales being the most significantly affected. Cd is the pollutant causing the greatest negative impact, but the presence of microplastics undoubtedly increases its toxicity.

Cadmium induced genotoxicity and antioxidative defense system in lentil (Lens culinaris Medik.) genotype

Induced mutagenesis is considered a coherent mechanism in crop improvement programmes to produce novel plant varieties. Due to the insufficiency of desired genotypes, plant breeders are supposed to re-associate the gene of interest from the accessible gene pool of the related plant species through hybridization to develop new cultivars with desired traits. The present investigation was performed to evaluate cadmium induced mutagenesis on growth performance, physio-biochemical traits and DNA damage studies in lentil. Growth and morphological parameters exhibited reduction with increasing concentration of cadmium. Maximum devaluation was reported at the highest concentration. Physiological and biochemical traits were also affected by different cadmium concentrations and reduced as concentration increased. Lipid peroxidation activity and antioxidant enzymes increased as mutagenic stress increased caused by cadmium. CAT and SOD concentration was found to increase initially and then decreased gradually at higher cadmium concentrations. SEM analysis of stomatal morphology revealed variation in stomatal shape and size in treated populations. There was a gradual enhancement in the percentage of DNA damage along with variation in morphological traits. The DNA damage was recorded as precocious movement, stray bivalent, laggard, stickiness, disorientation of chromosome, multi-bridge, disturbed polarity and micronuclei. It was concluded that at higher concentrations, cadmium cause DNA damage and these chromosomal alterations causes morpho-physiological and biochemical changes in lentil.

Phytoremediation by using Atriplex halimus subsp. schweinfurthii as a bio-absorbent of Cadmium in the soil

Background: The problem of soil contamination is a major concern of emerging countries. Heavy metals such as lead, cadmium, copper, zinc, and mercury cannot be biodegraded, and therefore, persist in the environment for long periods. It has become essential to develop efficient techniques for decontamination of polluted soils. One of these techniques, phytoremediation, is economically viable and compatible with environmental preservation policies. The application of phytoremediation in salty areas requires the use of plants that are able to tolerate heavy metals and high soil salinity. Atriplex halimus is one of the species with a great purification potential, which is a spontaneous halophyte species, and endowed with a fairly important aerial and root biomass. This study aimed to determine the effect of cadmium sulfate (CdSO4 ) on the germination and growth of A. halimus, and to assess its ability to accumulate cadmium and proline. Methods: This is an experimental study of the tolerance of A. halimus to increasing concentrations of CdSO4 by an in vivo test. This study aimed to assess the degree of tolerance of this perennial species towards different concentrations of CdSO4 . Results: The results show a non-significant effect of CdSO4 on the seed germination rate and growth of the aerial and root parts. However, a significant accumulation of proline was observed especially in the aerial part, whereas the highest cadmium content was recorded at the roots. Conclusion: According to the results, this species can be used in phytoremediation to decontaminate soils contaminated by heavy metals.

Evaluation of Cd phytoremediation by Portulaca oleracea irrigated by contaminated water

Background: Worldwide, more than 10 million regions with an area of more than 20 million hectares are considered contaminated soils. The expansion in industrial activities and urbanization has led to accumulation of high concentration of cadmium (Cd) in soil and water resources, which is a serious danger for environment and human health. Phytoremediation is a technique recommended for the removal of heavy metals from contaminated soils, sediments, and waters. This study aimed to investigate the Portulaca oleracea in the removal of Cd from contaminated soil. Methods: To investigate the effect of P. oleracea phytoremediation on the removal of Cd, in 5 pots, 3 kg of soil was poured. And in each pot, 10 seeds were pursued. The pots were irrigated twice a week for 8 weeks with concentrations of 25, 50, 75, and 100 mg/L Cd. After 8 weeks, the amount of Cd of roots, shoots, and leaves was measured by atomic absorption spectrometry. Results: The results showed that Cd accumulation in purslane plants was significant (P=0.008) and the highest Cd accumulation was in leaves and shoots, and increasing Cd concentration prevented plant growth and led to lower growth at higher concentrations. Conclusion: According to the results, P. oleracea can be used for the phytoremediation of Cd.

The Role of Oxygenated Functional Groups on Cadmium Removal using Pyrochar and Hydrochar Derived from Guadua angustifolia Residues

In the Ecuadorian Amazonia, there is a concern about the presence of high concentrations of cadmium (Cd) in rivers and sediments because of changes in land use and anthropogenic activities, e.g., mining and oil exploitation. Hence, the research related to water treatment processes to meet environmental standards has gained relevance. The use of biochar (BC) as adsorbent is considered a promising and low-cost alternative to improve the water quality in developing countries. In this work, lignocellulosic wastes from Guadua angustifolia were transformed through thermochemical treatments, into a promising carbonaceous material, such as BC. BC samples were prepared by pyrolysis (termed pyrochar, PC) and hydrothermal carbonization (termed hydrochar, HC). Their physicochemical properties were correlated with the Cd adsorption removal performance, analyzing the effect of adsorbent dosage, initial solution pH, adsorption kinetics and adsorption isotherms. HC showed the highest Cd adsorption performance, due to the presence of a higher number of oxygenated functional groups, as confirmed by FTIR, XPS and Raman spectroscopy. This research has proposed a sustainable alternative for the recovery of an available waste, contributing to mitigate the effects of the presence of metals on the health and economy of the most vulnerable sectors of society.

Previous stress causes a contrasting response to cadmium toxicity in the aquatic snail Potamopyrgus antipodarum: lethal and behavioral endpoints

In aquatic ecosystems, animals are often exposed to a combination of stressors, including both natural and anthropogenic factors. Combined stressors may have additive or interactive effects on animals, either magnifying or reducing the effects caused by each stressor alone. Therefore, standardized bioassays can lead to overestimations or underestimations of the risk of toxicants if natural stressors are not bear in mind. The inclusion of natural stress in laboratory bioassays may help to extrapolate the laboratory results to ecosystems. This study assesses the effects of successive exposure to two sources of stress (high water conductivity and cadmium toxicity) on the behavior and survival of the aquatic snail Potamopyrgus antipodarum (Tateidae, Mollusca). I conducted a bioassay consisting on exposure to high conductivity (5000 mg NaCl/L, 7 days), followed by exposure to cadmium (0.03, 0.125, and 0.25 mg Cd/L for 7 days) and by a post-exposure period (7 days). Mortality, inactivity, and the time to start activity of active animals were monitored in each animal. In general, cadmium lethality was higher in animals previously undergoing high conductivity than in non-stressed ones. Previously stressed animals showed longer time to start activity, with a noticeable effect at the two highest cadmium concentrations. Animals submitted to the two highest cadmium concentration both, stressed and non-stressed, showed a moderate recovery during the post-exposure period. It is concluded that previous stress caused a worsening of the cadmium toxicity on the aquatic snail Potamopyrgus antipodarum, which is especially noticeable for mortality. However, there was no interactive effect between cadmium and conductivity on snail activity, which may be indicative of recovery after cadmium exposure regardless the previous stress suffered by the snails.