Adverse Effects Of Heavy Metals Research Articles

Potential of amino acids-modified biochar in mitigating the soil Cu and Ni stresses – Targeting the tomato growth, physiology and fruit quality

Trace heavy metals (HMs) such as copper (Cu) and nickel (Ni) are toxic to plants, especially tomato at high levels. In this study, biochar (BC) was treated with amino acids (AA) to enhance amino functional groups, which effectively alleviated the adverse effects of heavy metals (HMs) on tomato growth. Hence, this study aimed to evaluate the effect of glycine and alanine modified BC (GBC/ABC) on various tomato growth parameters, its physiology, fruit yield and Cu/Ni uptake under Cu and Ni stresses. In a pot experiment, there was 21 treatments with three replications having two rates of simple BC and glycine/alanine enriched BC (0.5% and 1% (w/w). Cu and Ni stresses were added at 150 mg kg−1 respectively. Plants were harvested after 120 days of sowing and subjected to various analysis. Under Cu and Ni stresses, tomato roots accumulated more Cu and Ni than shoots and fruits, while GBC and ABC application significantly enhanced the root and shoot dry weight irrelevant to the stress conditions. Both rates of GBC decreased the malondialdehyde and hydrogen peroxide levels in plants. The addition of 0.5% GBC with Cu enhanced the tomato fruit dry weight by 1.3 folds in comparison to the control treatment; while tomato fruit juice content also increased (50%) in the presence of 0.5% GBC with Ni as compared to control. In summary, these results demonstrated that lower rate of GBC∼0.5% proved to be the best in mitigating the Cu and Ni stress on tomato plant growth by enhancing the fruit production.

Cadmium Exposure Impairs Development, Detoxification Mechanisms and Gene Expression of Glyphodes pyloalis Walker (Lepidoptera: Pyralidae)

Cadmium (Cd) is the most serious heavy metal pollutant in the agricultural soil of China and can transfer and accumulate through the food chain and affect the growth, development and physiological processes of phytophagous insect. Glyphodes pyloalis Walker (G. pyloalis) is one of the most important pests of mulberry, and there are few studies on the adverse effects of heavy metals on insects, especially mulberry pests. To understand the toxicology of Cd exposure on G. pyloalis, we investigated the effects of three different concentrations of Cd (0, 3.89 and 51.69 mg/kg, labeled as control check (CK), low dose (LD) and high dose (HD)) on the development and detoxification mechanism of G. pyloalis and explored the molecular mechanism of Cd on G. pyloalis larvae using RNA-seq technology. Transcriptome analysis showed that compared with the CK, a total of 63 differentially expressed genes (DEGs) were identified in LD exposure, including 24 upregulated and 39 downregulated candidates. In CK versus HD groups, 395 upregulated DEGs and 436 downregulated DEGs were identified and the expression patterns of 12 genes related to detoxification and metabolism were verified using qPCR. These DEGs were relevant to multiple specific peroxisome and drug metabolism-cytochrome P450 pathways. Gene annotation and quantitative real-time PCR revealed that a high concentration of Cd significantly stimulated the expression of metabolic detoxification enzyme genes. The results revealed that Cd exposure changed the pupal weight, adult emergence rate and the activities of AKP, ACP and GST in G. pyloalis and induced notable adverse effects at the molecular level on detoxification and metabolism such as concentration and time differences. In addition, we silenced CYP12A2 by RNA interference. Bioassays showed that after silencing CYP12A2, the survival rate of G. pyloalis under Cd exposure was lower than that of the control group.

Role of the molecular structure of humified organic matter in rice plant response to environmental lead pollution.

Humified organic matter has been shown to decrease Pb toxicity in plants. However, there are still gaps in our understanding of the mechanism by which this phenomenon occurs. In this study, we aimed to assess the ability of humic substances (HSs), humic acids (HAs), and fulvic acids (FAs) to enhance defense mechanisms in rice plants under lead (Pb)-stressed conditions. HS fractions were isolated from vermicompost using the chemical fractionation methodology established by the International Humic Substances Society. These fractions were characterized by solid-state NMR and FTIR. Chemometric analysis was used to compare humic structures and correlate them with bioactivity. Three treatments were tested to evaluate the protective effect of humic fractions on rice plants. The first experiment involved the application of humic fractions along with Pb. The second comprised pretreatment with humic fractions followed by subsequent exposure to Pb stress. The third experiment involved Pb stress and subsequent treatment with humic fractions. The root morphology and components of the antioxidative defense system were evaluated and quantified. The results showed that HS + Pb, HA + Pb, and FA + Pb treatment preserved root growth and reduced the levels of O2- and malondialdehyde (MDA) in the roots by up to 5% and 2%, respectively. Pretreatment of the plants with humic fractions promoted the maintenance of root growth and reduced the contents of O2-, H2O2, and MDA by up to 48%, 22%, and 20%, respectively. Combined application of humic fractions and Pb reduced the Pb content in plant tissues by up to 60%, while pretreatment reduced it by up to 80%. The protective capacity of humic fractions is related to the presence of peptides, lignin, and carbohydrate fragments in their molecular structures. These results suggest that products could be developed that can mitigate the adverse effects of heavy metals on agricultural crops.

Optimizing chili production in drought stress: combining Zn-quantum dot biochar and proline for improved growth and yield

The reduction in crop productivity due to drought stress, is a major concern in agriculture. Drought stress usually disrupts photosynthesis by triggering oxidative stress and generating reactive oxygen species (ROS). The use of zinc-quantum dot biochar (ZQDB) and proline (Pro) can be effective techniques to overcome this issue. Biochar has the potential to improve the water use efficiency while proline can play an imperative role in minimization of adverse impacts of ROS Proline, functioning as an osmotic protector, efficiently mitigates the adverse effects of heavy metals on plants by maintaining cellular structure, scavenging free radicals, and ensuring the stability of cellular integrity. That’s why current study explored the impact of ZQDB and proline on chili growth under drought stress. Four treatments, i.e., control, 0.4%ZQDB, 0.1 mM Pro, and 0.4%ZQDB + Pro, were applied in 4 replications following the complete randomized design. Results exhibited that 0.4%ZQDB + Pro caused an increases in chili plant dry weight (29.28%), plant height (28.12%), fruit length (29.20%), fruit girth (59.81%), and fruit yield (55.78%) over control under drought stress. A significant increment in chlorophyll a (18.97%), chlorophyll b (49.02%), and total chlorophyll (26.67%), compared to control under drought stress, confirmed the effectiveness of 0.4%ZQDB + Pro. Furthermore, improvement in leaves N, P, and K concentration over control validated the efficacy of 0.4%ZQDB + Pro against drought stress. In conclusion, 0.4%ZQDB + Pro can mitigate drought stress in chili. More investigations are suggested to declare 0.4%ZQDB + Pro as promising amendment for mitigation of drought stress in other crops as well under changing climatic situations.

Co-exposure of heavy metals in rice and corn reveals a probabilistic health risk in Guizhou Province, China

The adverse effects of heavy metals have arousing concern in the high geological background area, especially in southwestern Guizhou, China. However, the pollution status of heavy metals are still unclear when exposed to rice and corn in Guizhou province. Therefore, the concentration, pollution level, spatial distribution, and probabilistic health risks of Ni, Cr, Pb, Cu, and Zn are estimated in rice and corn. A total of 241 samples (117 for rice and 124 for corn) were collected from Guizhou province and measured by a method of inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that rice and corn were contaminated with Ni and Cr. High concentrations of Ni were presented in the southeast of rice. It indicated that 22.0 % of rice samples were contaminated with Ni. HI values for children and adults exceeded 1.0 in rice and corn, suggesting that humans might be subject to probabilistic non-carcinogenic risks. FTCR demonstrated that rice and corn might cause probabilistic carcinogenic risks to children and adults, which were both greatly higher than 1.0 × 10−4. Moreover, the contributions of Ni to the HI and FTCR were the highest for adults and children. Therefore, more attention should be paid to the exposure of heavy metals in rice and corn, especially in Ni. The results would provide a novel prospective for pollution control and be helpful for environmental regulation.

Influence of brassinosteroid and silicon on growth, antioxidant enzymes, and metal uptake of leafy vegetables under wastewater irrigation

Vegetable cultivation under sewage irrigation is a common practice mostly in developing countries due to a lack of freshwater. Long-term usage provokes heavy metals accumulation in soil and ultimately hinders the growth and physiology of crop plants and deteriorates the quality of food. A study was performed to investigate the role of brassinosteroid (BRs) and silicon (Si) on lettuce, spinach, and cabbage under lead (Pb) and cadmium (Cd) contaminated sewage water. The experiment comprises three treatments (control, BRs, and Si) applied under a completely randomized design (CRD) in a growth chamber. BRs and Si application resulted in the highest increase of growth, physiology, and antioxidant enzyme activities when applied under canal water followed by distilled water and sewage water. However, BRs and Si increased the above-determined attributes under the sewage water by reducing the Pb and Cd uptake as compared to the control. It’s concluded that sewerage water adversely affected the growth and development of vegetables by increasing Pb and Cd, and foliar spray of Si and BRs could have great potential to mitigate the adverse effects of heavy metals and improve the growth. The long-term alleviating effect of BRs and Si will be evaluated in the field conditions at different ecological zones.

Mitigation of the Deleterious Effect of Heavy Metals on the Conformational Stability of Ubiquitin through Osmoprotectants.

The Ubiquitin-Proteasome System (UPS) is important in protein homeostasis and is involved in many cell processes. UPS's wide range of regulatory activities is based on the unique and diverse signals transmitted through all-encompassing processes. Cells need a fully functional UPP to cope with oxidative stress, so cellular redox status modulates ubiquitin activity. However, these protein quality control systems are compromised under adverse conditions such as heavy metal stress, resulting in pathological conditions. Heavy metals disrupt the physiological action of sensitive proteins by forming complexes with side-chain functional groups or by dislocating critical metal ions in metalloproteins. In addition, perturbation in the structure of Ubiquitin may affect the ubiquitin-proteasome pathway. In this study, it has been investigated the effects of heavy metals likewise chromium (Cr), cadmium (Cd), and mercury chloride (HgCl2) on the conformational stability of Ubiquitin as well as overcome their hazardous effect, the interaction of osmo-protectants such as Sesamol, gallic acid, Glycine, and ascorbic acid have also been explored in the study. The near and far UV-circular dichroism measurements deduced the secondary and tertiary structural changes. The size of the Ubiquitin before and after exposure to heavy metals was measured by DLS (dynamic light scattering). Docking research was also used to investigate the interaction of Ubiquitin with various heavy metals. Near and far UV-circular dichroism (CD) measurements revealed that mercury, chromium, and cadmium disrupt Ubiquitin's secondary and tertiary structure. The effect of chromium, even at low concentrations, was significantly deleterious compared to cadmium and mercury chloride. Ubiquitin's far-UV circular dichroism spectra subjected to heavy metals were recorded in several osmo-protectants, such as ascorbic acid, Glycine, gallic acid, and Sesamol, which offset the adverse effects of heavy metals. DLS studies revealed a noteworthy change in the hydrodynamic radius of Ubiquitin in the presence of heavy metals. Docking analysis revealed a significant binding affinity of mercury and cadmium ions with Ubiquitin. This study can infer the heavy metals' disruption of Ubiquitin's secondary and tertiary structure. Osmo-protectants produced by animal cells are more effective against heavy metals than plant antioxidants.

NATURAL FORAGE LANDS OF EASTERN PODILLYA OF UKRAINE: ORIENTATION OF DYNAMIC PROCESSES AND OPTIMIZATION IN MODERN ECOLOGICAL CONDITIONS

The article presents an analysis of the state of natural forage lands of the Eastern Podillya of Ukraine. The analysis of the geobotanical survey of the natural forage lands of the Forest-Steppe of Ukraine proved that they are in an unsatisfactory state due to high anthropogenic load and need to be restored. The main sources of stress on natural ecosystems, including forage lands, are highlighted – industry, motor vehicle, sewage and household waste, as well as agricultural production, which are characterized by an excessive influx of toxic elements into the environment. Optimization of natural forage lands is an integral part of the concept of balanced development and national programs on the quality of the environment as a mandatory element of state policy. To optimize the restoration of contaminated natural forage lands, it is quite important to assess the risks from the adverse effects of heavy metals, to carry out an ecological assessment of this process, which can be the basis for large-scale measures to restore contaminated lands. Among a large number of toxic elements, heavy metals occupy a prominent place. In particular, there is an increased intake of lead, cadmium, zinc, and copper. It was found that in the conditions of dry land lowland meadows, normal dry lands are the safest and most suitable for providing herbivores with plant biodiversity. It has been proven that the accumulation of toxic substances in soils leads to their degradation, which is accompanied by a toxic effect on plants, causing a decrease in their reproductive quality. A significant man-made load of motor vehicles on the soils of the roadside space, which is accompanied by their contamination with heavy metals, was revealed. Based on the results of the research, a theoretical generalization was made and a solution to the current scientific and practical task was proposed regarding the assessment of the intensity of pollution of the natural lands of Vinnytsia region by heavy metals in the conditions of various man-made loads Installed it was found that the exceedance of the maximum concentration limit in the soils in the studied territories of local pollution of dry lowland meadows of Vinnytsia region was found only for cadmium by 1,01 times in the territories dry lands of excessive moisture adjacent to the railway connection.

Investigation of the combined effects of cadmium chloride, silver nitrate, lead nitrate, methyl jasmonate, and salicylic acid on morphometric and biochemical characteristics of St. John's wort.

Hypericum perforatum L., is a sprawling, leafy herb that grows in open, disturbed areas, known as St. John's wort, has a variety of secondary metabolites that can be used for medicinal and therapeutic purposes. Heavy metals have become the most dangerous pollutants in the environment. The effect of cadmium chloride, lead nitrate, silver nitrate, methyl jasmonate, and salicylic acid was studied on several morphometric and biochemical features of St. John's wort simultaneously using the Taguchi statistical method. The results showed cadmium chloride and lead nitrate reduced the morphometric and biochemical properties of St. John's wort while salicylic acid compensated for the adverse effects of heavy metals. Simultaneously, use of salicylic acid and silver nitrate with cadmium chloride and lead nitrate reduced the toxic effects of these metals on morphometric properties. Methyl jasmonate improved growth characteristics at low levels and inhibited at higher levels. Also, according to the results, salicylic acid could reduce the effects of heavy metals on the biochemical properties, while silver nitrate acts like heavy metals, especially at higher levels. Salicylic acid reduced the harmful effects of these heavy metals and at all levels was able to create a better induction effect on St. John's wort. These elicitors mainly changed the adverse effects of heavy metals by strengthening the pathways of the antioxidant system in St. John's wort. The research assumptions were validated, which suggests that the Taguchi method could beconsidered in an optimum culture of medicinal plants under different treatments such as heavy metals and elicitors.

Essential Trace Elements Prevent the Impairment in the Retention Memory, Cerebral Cortex, and Cerebellum Damage in Male Rats Exposed to Quaternary Metal Mixture by Up-regulation, of Heme Oxygynase-1 and Down-regulation of Nuclear Factor Erythroid 2-related Factor 2-NOs Signaling Pathways

In the present study, we examined adverse effects of metals and metalloids in the Cerebral cortex (CC) and Cerebellum (CE). Group 1 comprised from the controls while other four groups of male Wistar rats were treated with following pattern: Group II (Heavy Metal Mixture HMM only: PbCl2, 20 mg·kg−1; CdCl2, 1.61 mg·kg−1; HgCl2, 0.40 mg·kg−1, and NaAsO3,10 mg·kg−1), Groups III (HMM + ZnCl2); Group IV (HMM + Na2SeO3) and Group V (HMM + ZnCl2 + Na2SeO3) for 60 days per os. HMM promoted oxidative stress in the CC and CE of treated rats compared to controls; moreover, exposure to HMM led to increased activity of the AChE and pro-inflammatory cytokines; also, HMM promoted accumulation of caspase 3 and other transcriptional factors such as Nrf2 and decreased levels of Hmox-1. Essential metals reduced increased bioaccumulation of Pb, Cd, As and Hg in CC and CE caused by HMM exposure. Also, all mentioned adverse effects were diminished by essential metals treatment (Se and Zn). HMM exposed rats had considerably less escape dormancy than controls. Histopathological analysis revealed moderate cell loss at the intermediate (Purkinje cell) and granular layer.Zinc and selenium supplementations could reverse adverse effects of heavy metals at various cellular levels in neurons.

Application of Silicon and Selenium in Rice for Reducing Cadmium Stress

Rice is an essential part of the human diet in most parts of the world; On the other hand, the industrialization of societies has led to pollution of the environment, including heavy metal contamination of soil and water, which negatively affects rice production and quality. Therefore, finding ways to increase the yield and quality of this strategic crop seems essential. Several studies have been conducted in recent decades to find effective and inexpensive solutions to reduce the adverse effects of heavy metals in rice fields. Due to the negative effect of cadmium pollution on rice quality and yield, the current study aimed to investigate cadmium absorption and transfer mechanisms in rice (from absorption by roots to loading in grains), and its effects on rice morphology, physiology, and biochemistry (such as biomass, nutrient absorption, antioxidant defenses). Also, rice’s natural mechanisms for detoxifying cadmium were discussed. This study also intended to identify the absorption and transfer pathways of silicon and selenium in rice, their roles in improving rice structures, and their antagonistic effects on reducing cadmium stress (absorption, transport, and toxicity of cadmium).

Bioaccumulation of heavy metals in common carp fish (Cyprinus carpio) and its relationship with the protein content

The objective of the present study was to investigate the concentration of some heavy metals in the dorsal muscle, gills, and liver of common carp (Cyprinus carpio) from the Dukan lake, Suleimani, Iraq, and its relationship with fish protein content. The sampling was carried out in both the summer and winter seasons of 2021. Fish samples were collected from the water of Dukan lake. Biometry analysis and determining of protein content were carried out. Moreover, the heavy metal concentrations were measured in different tissues and organs of fish (the dorsal muscle, gills, and liver). The metal concentration varied considerably among different tissues and organs. Overall, the mean metal concentration revealed an order of Zn > Fe > Cr > Cd > Cu > As > Pb. The mean concentrations of Zn and Pb were determined as the maximum and minimum concentrations of metals in the fish organs, respectively. Metal accumulation was higher in the gills and liver than in the muscle (except Cr). The content of protein showed a close relationship with some of the metal concentrations. The concentrations of metals like As, Cd, and Cu were higher during the summer than in the winter, except for Cr and Fe. Due to the concerns related to the adverse effects of heavy metals in fish meat on human health, investigation of the concentration of pollution and regular monitoring of the physicochemical and heavy metal contents and its relationship with those measured in fish is strongly recommended.

Pollution Characteristics and Health Risk Assessment of Heavy Metals in Agricultural Soils over the Past Five Years in Zhejiang, Southeast China.

Heavy metal contamination in agricultural soils has attracted increasing attention in recent years. In this study, 1999 agricultural soil samples were collected from 11 cities in Zhejiang Province from 2016 to 2020, and the spatial and temporal variation characteristics of 3 of the most important heavy metals, i.e., lead (Pb), cadmium (Cd), and chromium (Cr) were analyzed. The results showed that Cd had a slightly higher sample over-standard rate of 12.06%. Spatial distribution and temporal trends showed that the Pb concentrations overall increased from 2016 to 2020 and mainly accumulated in southern Zhejiang. In addition, multiple exposure routes were evaluated for human health risks. Children are more susceptible to the adverse effects of heavy metals in agricultural soils, and oral ingestion was the major exposure route. Cr poses higher human health risks to humans than Pb and Cd in agricultural soils. Therefore, more rigid environmental monitoring and related soil remediation counter-measures for some sites with high concentrations of heavy metals are necessary to limit the potential threat to human health.

Heavy Metals in Tea and Their Adverse Effects on Mother and Fetal Outcome

This study aimed to analyze the adverse effects of heavy metals in tea on pregnant mothers and fetal outcomes, using Camellia sinensis tea as a more common beverage after water. The tea constituents are flavonoids containing catechins, which are primary polyphenols recognized as having a strong anti-oxidant activity preventing cellular damage by free radicals. During pregnancy, excessive tea intake negatively impacts the newborn. Tea constituents and their contamination have gained attention as heavy metal contamination exceeds its critical concentrations in tea infusions which may cause adverse effects on both mother and fetus. A total of 400 pregnant women participated in the present study. A cross-sectional study was conducted at the department of Physiology of University of Sindh in collaboration with the Department of gynecology and obstetrics of Liaquat University of Medical and Health Sciences (LUMHS), Jamshoro, from September 2018 to August 2020. Selected pregnant women were informed and gave written consent. Chemical analysis of maternal blood was conducted at the National Centre of Excellence in Analytical Chemistry, University of Sindh. The statistical data were analyzed using SPSS v 21.0 (IBM incorporation, USA). The student`s and Person tests for correlation were applied, presenting the results as mean ± standard deviation (SD). Statistical significance difference was calculated at 95% (p ≤ 0.05). The results of maternal parameters such as age, marital age, maternal height, body temperature, respiratory rate, and diastolic pressure had no significant difference. Simultaneously, gestational age, neck circumference, gestational weight gain, and systolic blood pressure had significant differences between pregnant tea and non-tea drinkers. Iron, Total iron-binding capacity (TIBC), and Ferritin also showed statistically significant differences at p < 0.0001. In the present study, the fetal weight positively correlated with aluminum, lead, mercury, and zinc and negatively correlated with copper and cadmium. Foot length showed a positive correlation with aluminum, copper, lead, cadmium, mercury, and zinc; the chest circumference showed a negative correlation with aluminum and copper.

Source, toxicity and carcinogenic health risk assessment of heavy metals.

Heavy metals are chemical elements with unique properties that are toxic even in low concentrations and affect human health with different functions. Agricultural and industrial activities, improper disposal of household solid waste and residues related to industrial producers, discharge of household wastewater and agricultural fertilizers are the most important ways in which toxic heavy metals enter the environment, which harms human health and life. A narrative review of the literature was done from 2000 to 2022 based on searched databases included Google Scholar, PubMed, Springer, Web of Science, and Science Direct (Scopus). All relevant studies published 2000 until 2022 gathered. According to the databases, 820 articles were retrieved. 186 and 50 articles were found and selected based on records identified through database searching and additional records identified through other sources. In thenext stage, 97 studies were screened after review and 64 full-text articles entered into the analysis process. Finally, 45 articles were selected in this study. Adverse effects of heavy metals on various conditions in the body depend on a number of factors, including dose, route of exposure and chemical species, as well as age, sex, genetics, nutritional status, and duration of exposure to the heavy metal. The existence of significant relationships between long-term and short-term exposure to toxic heavy metals and their adverse effects, including carcinogenicity, has been extensively studied and proven through numerous experiments. However, the mechanisms associated with this complication have not been properly identified, so in future research, there is a great need for comprehensive studies on the carcinogenicity of heavy metals.

The function of omega-3 polyunsaturated fatty acids in response to cadmium exposure.

Throughout history, pollution has become a part of our daily life with the improvement of life quality and the advancement of industry and heavy industry. In recent years, the adverse effects of heavy metals, such as cadmium (Cd), on human health have been widely discussed, particularly on the immune system. Here, this review summarizes the available evidence on how Cd exposure may affect health. By analyzing the general manifestations of inflammation caused by Cd exposure, we find that the role of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) in vivo can counteract Cd-induced harm. Additionally, we elucidate the effects of n-3 PUFAs on the immune system, and analyze their prophylactic and therapeutic effects on Cd exposure. Overall, this review highlights the role of n-3 PUFAs in the pathological changes induced by Cd exposure. Although n-3 PUFAs remain to be verified whether they can be used as therapeutic agents, as rehabilitation therapy, supplementation with n-3 PUFAs is reliable and effective.

Plant and microbe mediated bioremediation: A long-term remedy for heavy metal pollution

As we progress farther into the industrial age of the twenty-first century, we see that many types of pollutants emitted into the air, water, and land are becoming increasingly burdensome to our environment. These pollutants have a major impact on humans, plants, and animals. Heavy metals are the most hazardous elements in our ecosystem since they are extremely harmful to the environment and continue to build up in our food chain. We must learn about the harmful consequences of heavy metals and work to reduce them using the most environmentally friendly methods feasible. This review discusses how bioremediation helps to reduce heavy metal concentrations in our ecosystem using biological agents, such as algae, fungi, bacteria, and plants. The paper also investigates various phytoremediation and microbial remediation mechanisms involved in metal detoxification or transformation into less toxic forms, which lower the adverse effects of heavy metals in animals, plants, and humans.

Potential adverse effects of heavy metals on clinical health parameters of Caretta caretta from a nesting area affected by mining tailings in Brazil

BackgroundIn 2015, Brazil had its most notorious ecological disaster due to an iron mine dam collapse. It was considered the world's largest environmental disaster associated with mining industry. The tailings composed mostly of iron ore and silica, but with high levels of heavy metals reached the Atlantic Ocean, through the Doce River, sixteen days after the rupture. The region where the mud ran into the ocean is an important nesting area for loggerhead turtles (Caretta caretta) in Brazil (Povoação, Espírito Santo state). The aim of this study is to evaluate the heavy metal effects on the health parameters of loggerhead turtles that nest in the exposed area (Povoação, Doce river estuary) and compare them with turtles from another coastal area that was not affected by the tailings (Praia do Forte, Bahia state). MethodsAnimals’ health status was determined by a physical examination during which blood samples used to perform biochemical and hematological analysis were also obtained. Heavy metal concentrations were evaluated in the blood and carapace scutes. ResultsSea turtles from Povoação had a worse body condition with higher ectoparasitic and epibiont loads compared to Praia do Forte animals. They also showed eye lesions and more frequent fibropapillomatosis suggestive tumors. Several correlations between the contaminants and hematological and plasma biochemical analytes were found in loggerhead sea turtles from Povoação. Blood metal concentrations were distinct between nesting areas, with higher As, Cd, Cr, Fe, Pb, and Zn levels in animals from the affected area. In the carapace scute, the heavy metal levels were similar between sites. ConclusionThe occurrence of eye lesions, suggestive fibropapillomatosis tumors, worse body condition, higher ectoparasite count, greater epibiont loads, large number of correlations between health parameters and heavy metal levels, and higher levels of some metals in the blood of PV turtles indicates that the tailings could have a negative impact on the health and reproduction of these turtles. The long-term monitoring of the exposed area is important to quantify the direct and indirect impacts of the tailings on the health of these animals. Additionally, the data reported here are important for temporal and spatial comparative studies in the future.

Adapting the cultivation of industrial hemp (Cannabis sativa L.) to marginal lands: A review

AbstractMarginal lands are increasingly being considered for cultivating industrial and bioenergy crops to reduce the direct and indirect land‐use changes. This review investigates the feasibility of hemp (Cannabis sativa L.) cultivation under the biophysical constraints that characterize marginal lands, with the objectives of (i) determining to which extent hemp cultivation can be affected by the considered factors of marginality and (ii) determining the most pertinent adaptations of crop technical management. This work establishes that hemp is a species that can be considered particularly susceptible to adverse conditions, in particular regarding soil characteristics (heavy clay, coarse sand, shallowness) and dry climates. Heavy metals (HMs) contaminations do not appear to severely limit hemp's productivity, with the exception of thallium. The adverse effects of HMs on the profitability of hemp cultivation rather lie in limitations of the potential uses of hemp biomass for several end‐uses applications (e.g., textiles, food) because of the HM contents in the raw materials. On HM polluted soils, a single‐use fiber production destined to high‐added value applications such as bio‐based composites is the most suited production. Under dry climate, hemp productivity might be particularly affected depending on the soil quality and on the severity of the dryness. Hemp can be suited for mountain environments, in which the potential for harvesting the threshing residues as a source for medical application of cannabinoids might provide a supplemental added‐value to the crop. Overall, although hemp has often been considered as able to grow in harsh conditions, this review highlights that care should be given to such statements and hemp appears to be more suited for integrating conventional agro‐systems, in particular considering that it can be considered both as a food and industrial crop.

Effects of Heavy Metals on Bacterial Growth, Biochemical Properties and Antimicrobial Susceptibility

Heavy metals are metallic elements that occur naturally and have a high atomic weight and a density which is five times greater than the density of water. Several studies have demonstrated that metal contamination in natural environments could have an important role in the development and spread of antimicrobial resistance. This is of particular concern, considering that heavy metals usually occur at higher levels than pharmaceutically produced antimicrobials. Also, the bio-accumulative and non-biodegradable nature of heavy metals may result in long- term antimicrobial resistance selection pressure. Therefore, this study assessed the effects of Copper, Cobalt, Cadmium, Zinc and Lead salts on growth, biochemical properties and antimicrobial susceptibility of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus to commonly used antimicrobials. The selected bacteria were exposed to varying concentrations of the heavy metal salts ranging from 1 ppm to 1000 ppm after which growth was measured using a spectrophotometer. The effect on biochemical reactions and antimicrobial susceptibility were also tested by the use of conventional biochemical tests and Kirby-Bauer disk diffusion methods respectively. Different heavy metals affected the growth of each individual microorganism differently. Despite that, the growth of E. coli, P. aeruginosa and S. aureus was observed to be inversely proportional to the concentrations of the heavy metals used. Following exposure to heavy metals, E. coli and S. aureus showed no changes in their biochemical properties but P. aeruginosa gave a positive urease result contrary to the control. E. coli developed resistance to Levofloxacin, Meropenem and Tetracycline while S. aureus to Azithromycin and Gentamicin and P. aeruginosa developed resistance only to Meropenem. These results confirm the adverse effects of heavy metals on bacterial growth and reveals that heavy metals can cause changes in some biochemical properties of bacteria that produce any of these properties under stressful growing conditions. This research also supports the findings that heavy metals enhance the development of antimicrobial resistance in otherwise antimicrobial sensitive strains of bacteria. This study therefore, gives insight into the likely state of the proliferation of heavy metal induced antimicrobial resistance in heavy metal contaminated areas.