Lead Accumulation Research Articles

Effects of Different Control Measures on Cadmium and Lead Accumulation and Quality in Lettuce

To explore the safe utilization technology of farmland polluted by the heavy metals cadmium (Cd) and lead (Pb) and to realize the safe production of agricultural products, a pot experiment was conducted to investigate the effects of two soil passivators and five foliar inhibitors on Cd and Cd-accumulation and quality of lettuce with low Pb and Cd accumulation (KCW). The results showed that different control measures had different effects on the soil pH value of lettuce, and the application of 45 g·m-2biochar-based passivator had the most significant difference in improving the soil pH value, which was increased by 0.8 units compared with that in CK. By using 72 g·m-2 of humic acid passivator yielded notable difference in reducing the soil pH value of lettuce. A reduction of 0.25 units was achieved compared with that in CK. Among all the control measures, the application of 45 g·m-2 biocharcoal-based passivation agent had the best effect on reducing soil available Cd content, which was significantly reduced by 53% compared with that in CK, and the application of 135 g·m-2biocharcoal-based passivation agent had the best effect on reducing soil available Pb content, which was significantly reduced by 64% compared with that in CK. Spraying 0.8% FAK-Zn foliar inhibitor not only had the best control effect on reducing Cd and Pb contents in the edible parts of lettuce, which were significantly reduced by 77% and 60%, respectively, compared with that in CK, but it also significantly reduced Cd and Pb enrichment coefficients and transport coefficients from the root to the edible parts of the lettuce. Different control measures had different effects on the nutritional quality of lettuce, and 0.4% FAK-Zn foliar inhibitor had the best effect on soluble protein. The 0.6% FAK-Zn had the best effect on soluble sugar, and the 0.4% FAK-Zn inhibitor had the best effect on vitamin C content. The application of biocarbon-based passivator could effectively repair lettuce soil polluted by Cd and Pb, whereas the application of FAK-Zn leaf surface inhibitor could effectively inhibit the accumulation, absorption, and transfer of Cd and Pb in lettuce; improve the nutritional quality of lettuce; provide a theoretical basis for safe production of vegetables polluted by heavy metals; and promote the recycling of resources and environment.

Lead (Pb) deposition onto new and biofilm-laden potable water pipes

Heavy metals' interactions with plumbing materials are complicated due to the differential formation of biofilms within pipes that can modulate, transform, and/or sequester heavy metals. This research aims to elucidate the mechanistic role of biofilm presence on Lead (Pb) accumulation onto crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper potable water pipes. For this purpose, biofilms were grown on new pipes for three months. Five-day Pb exposure experiments were conducted to examine the kinetics of Pb accumulation onto the new and biofilm-laden pipes. Additionally, the influence of Pb initial concentration on the rate of its accumulation onto the pipes was examined. The results revealed greater biofilm biomass on the PEX-A pipes compared to the copper and HDPE pipes. More negative zeta potential was found for the biofilm-laden plastic pipes compared to the new plastic pipes. After five days of Pb exposure under stagnant conditions, the biofilm-laden PEX-A (980 μg m−2) and HDPE (1170 μg m−2) pipes accumulated more than three times the Pb surface loading compared to the new PEX-A (265 μg m−2) and HDPE pipes (329 μg m−2), respectively. However, under flow conditions, Pb accumulation on biofilm-laden plastic pipes was lower than on the new pipes. Moreover, with increasing the initial Pb concentration, greater rates of Pb surface accumulation were found for the biofilm-laden pipes compared to the new pipes under stagnant conditions. First-order kinetics model best described the Pb accumulation onto both new and biofilm-laden water pipes under both stagnant and flow conditions.

Bioremediation potential of rhizosphere bacterial consortium in lead (Pb) contaminated rice plants

Abstract. Ubaidillah M, Thamrin N, Cahyani FI, Fitriyah D. 2023. Bioremediation potential of rhizosphere bacterial consortium in lead (Pb) contaminated rice plants. Biodiversitas 24: 4566-4571. Lead (Pb) is one of the toxic heavy metals detected in various chemical fertilizers and pesticides used in Indonesia. These chemicals can increase plant lead (Pb) accumulation and affect other organisms through its circulation with food chain. Excess amounts of Pb in soil may be remediated using different approaches such as bioremediation. Rhizosphere bacteria can be used as bioremediation agents to reduce Pb accumulation in plants and also increase plant growth. Actinomycetes, Azotobacter sp., Azospirillum sp., Rhizobium sp., Pseudomonas sp., Lactobacillus sp., Bacillus sp., and Streptomyces sp. are some of the several bacteria that can reduce lead (Pb) accumulation in plants by the ability to sequester Pb, change its oxidation state, or enable Pb to precipitate. This research was conducted to determine the ability of the rhizosphere bacterial consortium to prevent lead (Pb) accumulation in rice plants. This study confirmed that the application of rhizosphere bacterial consortium to rice plants contaminated with lead (Pb) can reduce the plant's lead (Pb) content by up to 45%. The use of a bacterial consortium did not significantly affect the growth parameters of the plant but increased root length by 41%, fresh weight by 32%, dry weight by 26%, and chlorophyll content by 25%, in rice plants contaminated with Pb.

Spatial Analysis of Cadmium and Lead in Soils of Nagaon District of Assam, India

Aims: The study was carried out in order to find the hotspots of Cadmium and Lead accumulation in the soil due to the anthropogenic activities, so that proper management strategies can be taken on time for their remediation.
 Study Design: Different geospatial techniques as Normal Q-Q plot, histogram, trend analysis and semi-variogram cloud model is used.
 Place and Duration of Study: The study was conducted emphasizing basically in high agricultural chemicals dependent Nagaon District of Assam, India, from 2018 to 2021.
 Methodology: Heavy metals were assessed using a random sampling method with a 5 x 5 km2 grid, and a total of 160 samples were collected from a depth of 0 – 15 cm for soil. Choropleth maps were created to show the distribution and hotspots of pollution.
 Results: Geospatial analyses from different thematic maps of heavy metals revealed significant vulnerable points of elevated concentrations of Pb (>24.45 mg/kg) and Cd (>0.31 mg/kg) in soil which is presumed to be due to anthropogenic factors. The three-dimensional trend over the distribution of metals throughout the district best fitted the second-order polynomial for Cd, and Pb in soils. Significant numbers of pairs of heavy metal pairs to a certain extent were found to be spatially autocorrelated and all the pairs away from X-axis towards the extreme right corner and far above the axis reflected less influence of local characteristics of the heavy metal. Co-variance cloud with search direction from North to South revealed the existence of spatial autocorrelation and a wider spatial shift of correlation towards the southern direction.
 Conclusion: The current study provides baseline data to update the mitigation approaches to better manage the heavy metal contamination in soil in the entire district.

Effect of tetrapeptide Acetyl-(D-Lys)-Lys-Arg-Arg-amide on immunological and biochemical parameters of Wistar rats using passive smoking models

Tetrapeptides, the homologues of adrenocorticotropic hormone fragment (15-18), play a special role among the bioregulators of the immune system. These compounds have cerebroprotective, neuroprotective and antioxidant properties. However, no available studies concerned the immunotropic properties of tetrapeptides in the models with exposure to xenobiotics, thus making such research quite relevant. Our study concerned the effects of tetrapeptide Acetyl-(D-Lys)-Lys-Arg-Arg-amide (laboratory code KK1) on the immunological and biochemical parameters of 72 female Wistar rats exposed to passive smoking. The experimental animals were fumigated with tobacco smoke for 8 hours. Synthetic peptide KK1 was administered intranasally at a dose of 40 g/kg/day five times a day for 10 days. Cotinine was detected only in blood serum of rats from experimental groups, thus confirming a contribution of this tetrapeptide to the trend for normalization of some immunological parameters in experimental animals subjected to passive tobacco smoking, expressed as an increase in thymus mass and the number of splenocytes, and a decrease in the circulating immune complexes compared to the parameters of smoking rats of the group. We revealed that passive tobacco smoking in rats was accompanied by a general tendency to accumulation of iron, lead and nickel in peripheral blood. There was a marked increase in the concentration of cadmium, lead and cobalt in rats of the experimental group compared with the content of these trace elements in the liver of smoking animals injected with tetrapeptide KK1. The revealed shifts in immunological indices may be based, firstly, on hepatotoxic effect of ecotoxicants, The lymphoid lineage is mostly affected thus causing hypoplasia of the central and peripheral immunity organs. An evident sign of such pathology is a decreased cellularity of hematopoietic and lymphoid organs found in the present study. Secondly, the tobacco smoke components with prooxidant action may disrupt cellular redox homeostasis, causing damage to cell membranes, resulting in necrosis or apoptosis, thus explaining the revealed decrease in the number of thymocytes, splenic karyocytes and a decrease in the weight of organs. Thus, our results suggest usage of experimental passive smoking in order to evaluate efficiency of the tetrapeptides. Administration of Acetyl-(D-Lys)-Lys-Arg-Arg-amide peptide to the passively smoking rats is associated with tendency to normalize the mass of the thymus and spleen, the number of thymocytes and splenocytes, and a decrease in circulating immune complexes. Further studies are required to elucidate the effects of tetrapeptides upon the immune system.

Lipoic acid abates testis lead accumulation, sperm-endocrine deficits, testicular oxidative inflammation and apoptosis and modulates gene expression of Bax and Bcl-2 in rats

The current study explored whether ALA could prevent testis Pb accumulation and Pb-induced oxidative testicular toxicity in rats. Adult male rats were randomly divided and administered ALA (25 mg/kg/day) and/or Pb (Pb acetate, 20 mg/kg/day) in Control group, ALA group, Pb group, and ALA + Pb group for 4 weeks consecutively. Pb exposure significantly increased Pb accumulation in the testes and blood of Pb-exposed rats compared to the control. Pb caused marked deficits in sperm count, motility along with elevated abnormal sperm cells, while serum testosterone, follicle stimulating hormone (FSH) and leutenizing hormone (LH) levels reduced prominently in comparison to the control. It remarkably depressed the testicular activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), as well as levels of interleukin-4 (IL-4) and interleukin-10 (IL-10), whereas malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) increased significantly compared to the control. The levels of caspase-3, capsase-9, and the PCR gene expression of Bax and Bcl2 were adversely altered with alterations in testis histology. Interestingly, the co-treatment with ALA blocks Pb accumulation in the testis and blood. It inhibited the Pb-induced alterations in reproductive indices and reversed the oxidative stress-mediated inflammatory stress, apoptotic signaling and histopathological abrasions. The findings reveal that ALA could abrogate Pb-induced testicular toxicity through blocking testicular oxidative inflammation and apoptosis in rats.

Linking Metallic Micronutrients and Toxic Xenobiotics to Atherosclerosis and Fatty Liver Disease-Postmortem ICP-MS Analysis of Selected Human Tissues.

Dyslipidaemia is a disorder of the lipid metabolism, caused mainly by poor eating habits. The most severe consequence of an inappropriate diet is the development of atherosclerosis and hepatic steatosis. It is generally believed that a change in nutrition, and increased physical activity can eliminate these health problems. The contemporary research and therapies used to treat dyslipidemia mainly focus on lowering the triglyceride and cholesterol levels. However, disturbances in trace element homeostasis or the accumulation of toxic elements can also affect physiological processes, and be involved in the development of metabolically mediated diseases. The present study aimed to determine the mineral profiles of liver and brain tissues collected at autopsy (n = 39) in groups of people with hepatic steatosis (n = 5), atherosclerosis (n = 9), hepatic steatosis, and atherosclerosis (n = 16), and others without the selected disorders (n = 9). Concentrations of 51 elements were analysed via inductively coupled plasma mass spectrometry (ICP-MS) after the initial wet mineralisation of the samples with nitric acid. The results obtained allow us to conclude that the hepatic steatosis group suffers from a deficiency of important trace elements, such as copper, zinc, and molybdenum (p < 0.05), whereas the group with atherosclerosis is characterised by elevated levels of cadmium in the liver tissue (p = 0.01). Analysing the mean values of the element concentrations measured in 11 brain areas, statistically significant higher levels of calcium and copper (p < 0.001) were found in the atherosclerosis group, compared to the hepatic steatosis group, confirming the involvement of these elements in the pathogenesis of atherosclerosis. In addition, an accumulation of cadmium, lead, titanium, and strontium in the brain tissue was observed in the atherosclerosis group. While the accumulation of individual elements differs in different parts of the brain, the differences in the cadmium content (p < 0.05) between the study groups apply to the whole brain, except for the nucleus accumbens septi area, where a statistically significant titanium accumulation occurs in the atherosclerosis and steatosis groups, compared to the others (p < 0.05). In addition, the disruption of elemental homeostasis in the brain of a single case with bipolar disorder, and a case with hip replacement was observed. Our results confirm the involvement of chemical elements in the pathogenesis of selected metabolic diseases, and the need for further studies in larger populations.

Spatio-temporal accumulation and sources of anthropogenic Pb in Ulleung Basin sediments, East/Japan Sea, based on stable Pb isotope ratios.

The accumulation, pathways, and sources of anthropogenic lead (Pb) in Ulleung Basin sediments were investigated based on the temporal and spatial variations in the Pb concentration and stable Pb isotopes for 21 dated box core sediments collected from the shelf, slope, and basin in the southern East/Japan Sea. Leached (1M HCl) Pb concentrations and isotope ratios (207Pb/206Pb and 208Pb/206Pb) were nearly constant before 1930, but have increased rapidly until the present. The primary source of anthropogenic Pb is considered to be atmospheric deposition, showing the signature of a mixture of leaded gasoline and coals, which was the major anthropogenic source in the basin. However, after the 1990s, anthropogenic Pb from dumping materials added as much as 10-25% to the slope sediment and has been spreading out from the water column accompanied by the movement of the East Sea Intermediate Water. In shelf areas, inputs from nonferrous refineries in the coastal industrial complexes play an important role in pollution from anthropogenic Pb.

Sufficient Phosphorus Enhances Resistance and Changes Accumulation of Lead in Chlamydomonas reinhardtii.

Phosphorus (P) is critical for algal growth and resistance to environmental stress. However, little is known about the effects of P supply on the lead (Pb) toxicity and accumulation in microalgae. We set up two P concentrations, 315 (PL ) and 3150 μg L-1 (PH ), in algal culture, and the responses of Chlamydomonas reinhardtii to various Pb treatments (0, 200, 500, 1000, 2000, and 5000 μg L-1 ) were investigated. Compared with the PL condition, PH promoted cell growth but reduced cellular respiration by approximately 50%. Moreover, PH alleviated damage to the photosynthetic system in algal cells after Pb stress. After exposure to 200-2000 μg L-1 Pb, higher Pb2+ concentrations and Pb removal were observed in the PL medium. However, under exposure to 5000 μg L-1 Pb, less Pb2+ was present but more Pb was removed by the algal cells in the PH medium. More P supply enhanced the secretion of extracellular fluorescent substances by C. reinhardtii. Transcriptomic analysis showed that genes associated with synthesis of phospholipids, tyrosine-like proteins, ferredoxin, and RuBisCO were up-regulated after Pb exposure. Together the findings of our study demonstrated the critical roles of P in Pb accumulation and resistance in C. reinhardtii. Environ Toxicol Chem 2023;00:1-11. © 2023 SETAC.

Bioaccumulation Pattern and Health Risk Assessment of Heavy Metals in Cirrhinus mrigala at Panjnad Headworks, Bahawalpur, Pakistan.

Heavy metal accumulation in freshwater ecosystem has become one of the major aquatic environmental concerns for freshwater flora and fauna due to their higher stability and bioaccumulation as well as bio-magnification properties. Furthermore, passing through the food web, these heavy metals affect human populations ultimately. This study assessed the heavy metal accumulation in Cirrhinus mrigala in spring, autumn, and winter at different locations (I, II, and III) of Panjnad headwork. Furthermore, the human health risk assessment for the consumption of C. mrigala from the sampling locations was also carried out. Fish were collected from upper (I), middle (II), and lower (III) stream of Panjnad on a monthly basis. The current study evaluated the accumulation of Aluminum (Al), Arsenic (As), Barium (Ba), and Lead (Pb) in various fish organs (liver, kidney, gills, fins, skin, muscles and bones) and assessed their potential hazard to human health through health risk assessment indicators. The results demonstrated a significant difference (p < 0.05) in heavy metal accumulation in different fish organs, seasons, and locations. The accumulation of Al, As, Ba, and Pb were considerably higher in liver and kidney as compared to the other body organs and followed a trend of liver > kidney > gills > fins > skin > bones > muscle and the overall mean concentrations of metals in different body tissues of C. mrigala were in the order of Al > As > Ba > Pb. The results also concluded that C. mrigala caught from the Panjnad headwork is not safe for human consumption due to higher values of TTHQIng (3.76), THQIng for Ba (3.27) and CRIng for As (6.4742).

The Dynamic of Lead Accumulation in the Almond Leaves and in the Parts of the Fruit

Plodovi bajama (jezgra) smatraju se diljem svijeta zdravom hranom jer osim svoje visoke nutritivne vrijednosti u povećanim koncentracijama sadrže i esencijalne bio-molekule, koje pozitivno djeluju na ljudski metabolizam i istodobno preveniraju najvažnije imunološke bolesti. Slijedom toga su u ekološkim uvjetima Ravnih kota ra provedena dvogodišnja istraživanja nakupljanja olova (Pb) u listu i pojedinim dijelovima ploda te istraživanja njihove korelacije. Od trenutka zametanja ploda prema zriobi razina Pb blago opada u svim dijelovima ploda, dok je kod lista to dvostruka sigmoidna krivulja. Razina Pb u listu je gotovo dvostruko veća negoli u dijelovima ploda, posebice u odnosu na jezgru i prema kraju vegetacije, što ukazuje na vrlo slabo premještanje Pb iz lista u sjemenku i/ili imobilizaciju Pb u endodermu lista. Razina Pb u jezgri bajama u fenofazi zrelosti kretala se od 0,27±0,031 do 0,40±0,021 mg/kg suhe tvari. To je izuzetno niska razina u odnosu na drugo voće, koje u svježem stanju sadrži veće razine Pb, a na razini suhe tvari nerijetko i tri do četiri puta više. Utvrđene su pozitivne korelacije između jezgre i koštice, odnosno lupine. Može se sa sigurnošću reći da se jezgra bajama proizvedena u ekološkim uvjetima Ravnih kotara može koristiti kao funkcionalna hrana, ali i kao sastavni dio hrane za dojenčad.

Phytoremediation method and Brassica family: Removal of chromium, cadmium and lead accumulation with broccoli (Brassica oleracea var. italica)

Phytoremediation is the most cost effective and applicable technique to clean contaminated soils. The study was carried out in controlled conditions. Cadmium was applied as only cadmium (30 mgkg−1), and together with a chelator as Cd (30 mgkg−1) + EDTA, in triplicates. Chromium was applied as only chromium (10 mg/kg−1), and together with a chelator as Cr (10 mgkg−1) + EDTA. Similarly, lead was applied as only lead (100 mgkg−1), and together with a chelator as Pb (100 mgkg−1) + EDTA. The highest root and shoot dry weights were detected in lead and chromium applied pots. The highest lead, cadmium and chromium concentrations in the shoot of broccoli (Brassica oleracea var.italica) were found to be 14.0 mgkg−1, 6.67 mg kg-1and, 5.17 mg kg−1, respectively, in the chelated applications. The order of accumulation in the root was Cr > Pb > Cd. Broccoli was shown to be effective in phytoextraction of Pb Chromium was especially accumulated in the roots of broccoli which indicated that this plant was successful for phytostabilization of Cr. Broccoli can be employed for both phytostabilization and phytoextraction of cadmium. The results revealed that broccoli played a role in the remediation of lead, chromium and cadmium heavy metals as a hyper accumulator plant.

The absorption and accumulation of lead in dracaena sanderiana plant

Heavy metals are the most dangerous substances in the environment, have caused deleterious effect not only to the environment but also to the public’s health. Different studies have demonstrated that plants have a high removal capacity for lead ions from pollution sources. However, these plant species were rather limited. Thus, the project aimed to find out plant species that represent its lead removal ability to reduce environmental pollution. The experiment was carried out factorially as a randomized complete design in hydroponic systems with four treatments (0, 100, 200, and 300mg/l of Pb) and three replications. The results indicated that the growth of the Dracaena sanderiana plant is well in Pb concentration of 100mg/l, with less growth while the increasing lead concentration of 200 mg/l and 300 mg/l. The amount of lead in the water of three treatments 100mg/l, 200mg/l, and 300mg/l after 30 days of the experiment decreased by 91.5%, 86.8%, and 86.4%, respectively. It was found that Dracaena sanderiana exhibited high lead treatment efficiency in the water. Moreover, results showed that the accumulation of lead in the roots of Dracaena sanderiana is quite large with treatments of 100mg/l, 200mg/l, and 300mg/l lead concentrations were 5073.8mg/kg, 5134.0mg/kg, 7054.0mg/kg, respectively. In contrast, the ability to lead accumulation in plant leaves and stems is lower.

Lead (Pb) accumulation in the Indonesian intensive farming system

One of the factors of soil pollution in paddy soil is the heavy metal lead (Pb). Lead is an element that is not essential for plants, with a content ranging from 0.1 - 10 µg/kg, and in various plants, it normally ranges from 0.5 - 3.00 µg/kg. This study aims to determine the content of lead (Pb) in soil and rice plants, as well as some of the chemical properties of the soil in the central rice area located in Marga Cinta, Belitang Madang Raya District, East Ogan Komering Ulu, South Sumatra, Indonesia. This study used a detailed survey method with a working map scale of 1:9,000. The paddy field studied covered 96 hectares divided into 6 locations, which were sampled using a random sampling method. Each location had 5 soil drilling points, and composite samples were created. Soil sampling was carried out by augering at a depth of 0-30 cm. The results showed that the content of lead (Pb) in paddy soil ranged from 9.90 – 12.18 µg/g with an average of 10.56 µg/g, while the content of lead (Pb) in rice plants was below the detection limit of the tool, with a value of &lt;0.0002 µg/g. The conclusion from the study was that the content of the heavy metal lead (Pb) in paddy soil and rice plants at the study site was still below the threshold.

Lead (Pb) accumulation in the Indonesian intensive farming system

One of the factors of soil pollution in paddy soil is the heavy metal lead (Pb). Lead is an element that is not essential for plants, with a content ranging from 0.1 - 10 µg/kg, and in various plants, it normally ranges from 0.5 - 3.00 µg/kg. This study aims to determine the content of lead (Pb) in soil and rice plants, as well as some of the chemical properties of the soil in the central rice area located in Marga Cinta, Belitang Madang Raya District, East Ogan Komering Ulu, South Sumatra, Indonesia. This study used a detailed survey method with a working map scale of 1:9,000. The paddy field studied covered 96 hectares divided into 6 locations, which were sampled using a random sampling method. Each location had 5 soil drilling points, and composite samples were created. Soil sampling was carried out by augering at a depth of 0-30 cm. The results showed that the content of lead (Pb) in paddy soil ranged from 9.90 – 12.18 µg/g with an average of 10.56 µg/g, while the content of lead (Pb) in rice plants was below the detection limit of the tool, with a value of &lt;0.0002 µg/g. The conclusion from the study was that the content of the heavy metal lead (Pb) in paddy soil and rice plants at the study site was still below the threshold.

Influence of combined stress by salinity (NaCl) and heavy metals (Pb(NO3)2) on the proline, chlorophyll and lead accumulation in the tissues of the Atriplex canescens (Pursh ) Nutt.

Abstract. Salinity and heavy metals pollution are the root causes of many environmental problems. This study aims to determine the effect of NaCl-induced salinity and Pb(NO3)2 on chlorophyll, proline content, and lead accumulation in shoots and roots of Atriplex canesens. Sowing was carried out in plastic pots (16 cm in diameter and 13.8 cm high) containing a mixture of sand/compost. The irrigation of plants was performed with distilled water and Hoagland nutrient solution. After four months of growth, the plants were subjected to either 0.50 or 3% of NaCl combined with 800, 1600, and 2400 ppm of Pb(NO3)2 for a duration of one month, then we performed biochemical and chemical analyses on the plants. Results showed that the combined influence of strong salinity and lead caused a reduction of chlorophyll and increased proline and lead accumulation in plant tissues. Lead significantly accumulated in the roots compared to the shoots of the plants.

The metabolism and detoxification effects of lead exposure on Aleurolyphus ovatus (Acari: Acaridae) via transcriptome analysis

Aleurolyphus ovatus Troupeau is one of the most predominant species of the Acaridae family worldwide. Recent reports have demonstrated that the accumulation of lead in stored grains and dietary items exceeds the required standards. However, the molecular mechanism of heavy metal stress on mites has not been reported. To understand the mechanism underlying the heavy metal response of A. ovatus, comparative transcriptome analysis was performed in this study using an Illumina high throughput mRNA sequencing (RNA-seq) platform. A. ovatus was fed on artificial diets containing two different concentrations of lead, namely, a low concentration of 12.5 mg/kg (LAO) and a high concentration of 100 mg/kg (HAO), while the mites in the control (NAO) group were not exposed to lead. A total of 44,362 unigenes, with an average length of 1547 bp, were identified. Of these, 996 unigenes were successfully annotated in seven functional databases. The number of differentially expressed genes (DEGs) in A. ovatus under different lead concentrations was compared. In NAO versus LAO group, including 310 up-regulated and 1580 down-regulated DEGs. In NAO versus HAO group, including 3928 up-regulated and 1761 down-regulated DEGs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment indicated that detoxification enzyme genes were significantly expressed in pathways, such as cytochrome P450 foreign body metabolism, glutathione metabolism and drug metabolism-cytochrome pathway. The results of gene annotation and quantitative real-time PCR showed that high concentration of lead significantly stimulated the expression of metabolic detoxification enzyme genes such as glutathione S transferase (GST) and superoxide dismutase (SOD), while low concentration inhibited their expression. This study will provide a basis for the molecular mechanism of A. ovatus in response to heavy metal lead stimulation in stored grain.

Mechanisms of lead uptake and accumulation in wheat grains based on atmospheric deposition-soil sources

Lead (Pb) accumulation in wheat grains depends on two aspects: i) Pb uptake by the roots and shoots, and ii) the translocation of organ Pb into the grain. However, the underlying mechanism of the uptake and transport of Pb in wheat remains unclear. This study explored this mechanism by establishing field leaf-cutting comparison treatments. Interestingly, as the organ with the highest Pb concentration, only 20.40 % of the root's relative contribution to grain Pb. The relative contributions of the spike, flag leaf, second leaf, and third leaf to grain Pb were 33.13 %, 23.57 %, 13.21 %, and 9.69 %, respectively, which was opposite to their Pb concentration distribution trends. According to Pb isotope analysis, it was found leaf-cutting treatments reduced the proportion of atmospheric Pb in grain, and grain Pb predominantly comes from atmospheric deposition (79.60 %). Furthermore, from the bottom to the top, the concentration of Pb in internodes decreased gradually, and the proportions of Pb originating from soil in the nodes also decreased, revealing that wheat nodes hindered the translocation of Pb from roots and leaves to the grain. Therefore, the hindering effect of nodes on the migration of soil Pb in wheat resulted in atmospheric Pb having a more convenient pathway to the grain than soil Pb, and further leading grain Pb accumulation primarily depended on the contribution of the flag leaf and spike.

Histopathological Changes in the Gill and Intestine Tissues of Fish from Pichavaram Mangroves, South east Coast of India

A study was conducted to analysis the Histopathological Changes in the Gill and Intestine Tissues of Mystus gulio and Mugil cephalus from Pichavaram Mangroves for different seasons. The maximum overall metal concentrations of Iron (Fe) recorded in the gills of M. cephalus was found to be maximum in S2 as 48.41±0.72 mg/l, copper (Cu) is maximum at station 6 as 0.52±0.02 mg/l, chromium (Cr) accumulation in the gills of M. gulio was highest in S5 as 5.23±0.05 mg/l, the highest lead (Pb) accumulation in the gills of M. gulio was found to be maximum in S6 as 0.71±0.03 mg/l. Likewise, the highest Iron (Fe) accumulation in the kidney of M. gulio was found to be maximum in S2 as 36.13±0.41 mg/l followed by copper (Cu) in (S6) 0.41±0.02 mg/l, Chromium (Cr) in (S6) records at 2.98±0.06 mg/l and by lead (Pb) maximum in S5 0.64±0.06 mg/l. The highest Iron (Fe) accumulation is found in the liver of M. gulio in S2 as 29.14±0.34 mg/l, followed by copper (Cu) in (S3) 0.32±0.01 mg/l, Chromium (Cr) in (S6 and S1) as 2.98±0.06 &amp; 2.98±0.03 mg/l respectively and in lead (Pb) the highest concentration is recorded at S6 1.10±0.06 mg/l. The highest Iron (Fe) accumulation is found in the intestine of M. gulio was found to be maximum in S6 as 29.11±0.44 mg/l and by copper (Cu) in (S6) 1.61±0.01 mg/l and chromium (Cr) in (S5) as 2.43±0.03 mg/l and in lead (Pb) at S6 1.74±0.03 mg/l. The highest Iron (Fe) accumulation is found in the muscle of M. gulio in S1 as 14.03±0.37 mg/l, followed by copper (Cu) in (S2) 1.83±0.06 mg/l, Chromium (Cr) in (S6) as 2.63±0.03 mg/l and in lead (Pb) the maximum in S6 1.52±0.03 mg/l.

Evaluation of calcium, phosphorus and soil organic matter effects on lead accumulation in Cenchrus ciliaris L. grown near a cement factory in Jazan region, Saudi Arabia

Heavy metals associated with cement production and their environmental impacts have received much attention recently. Lead (Pb) is the second most hazardous element after arsenic (As). However, information about its availability and uptake by plants in polluted soil as influenced by soil properties has shown some contradictions. We evaluated the influence of soil calcium (Ca), soil phosphorus (P), and soil organic matter (SOM) on Pb uptake by Cenchrus ciliaris L. based on distance from cement dust polluted soil near a cement factory in Jazan region, Saudi Arabia. We also evaluated the potential of Cenchrus ciliaris L. as a hyperaccumulator of Pb. Soil and plant samples were collected in triplicates from three zones based on distance from the fence of the factory: 10 – 100, 100 – 350, and 350 – 700 m. Concentrations of total Pb, total Ca, and total P in soil and plant tissues were detected using ICP-AES. SOM and other soil properties were also analyzed. Bioconcentration and translocation factors (BF&TF) of Pb were also calculated. Results showed that Pb concentration in Cenchrus ciliaris roots had a strong negative relationship with SOM (R2 = 0.93) and P concentration in soil (R2 = 0.97) but a moderate negative relationship with Ca concentration in soil (R2 = 0.69). The highest TF value was 1.87. It can be concluded that SOM, Ca, and P concentrations in soil negatively affected Pb availability and uptake by Cenchrus ciliaris. Also, based on the highest TF value, Cenchrus ciliaris could be used as a hyperaccumulator in Pb-contaminated soils.