Metal Concentrations In Water Research Articles

Nanomaterials Based on 2,7,12,17-Tetra-tert-butyl-5,10,15,20-tetraaza-21H,23H-porphine Exhibiting Bifunctional Sensitivity for Monitoring Chloramphenicol and Co2.

Monitoring antibiotic retention in human body fluids after treatment and controlling heavy metal content in water are important requirements for a healthy society. Therefore, the approach proposed in this study is based on developing new optical sensors using porphyrin or its bifunctional hybrid materials made with AuNPs to accomplish the accurate detection of chloramphenicol and cobalt. To produce the new optical chloramphenicol sensors, 2,7,12,17-tetra-tert-butyl-5,10,15,20-tetraaza-21H,23H-porphine (TBAP) was used, both alone in an acid medium and as a hybrid material with AuNPs in a water-DMSO acidified environment. The same hybrid material in the unchanged water-DMSO medium was the sensing material used for Co2+ monitoring. The best results of the hybrid materials were explained by the synergistic effects between the TBAP azaporphyrin and AuNPs. Chloramphenicol was accurately detected in the range of concentrations between 3.58 × 10-6 M and 3.37 × 10-5 M, and the same hybrid material quantified Co2+ in the concentration range of 8.92 × 10-5 M-1.77 × 10-4 M. In addition, we proved that AuNPs can be used for the detection of azaporphyrin (from 2.66 × 10-5 M to 3.29 × 10-4 M), making them a useful tool to monitor porphyrin retention after cancer imaging procedures or in porphyria disease. In conclusion, we harnessed the multifunctionality of this azaporphyrin and of its newly obtained AuNP plasmonic hybrids to detect chloramphenicol and Co2+ quickly, simply, and with high precision.

Heavy metal concentrations in water from Bakkhali River estuary, Cox’s Bazar, Bangladesh

Heavy metals contamination of water is considered as severe global issues for developing countries like Bangladesh. Because heavy metal pollution ruined aquatic ecosystem especially fish diversity which contribute important share on economy of a country. The present study designed to investigate the contamination level of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu) and zinc (Zn) in surface water of Bakkhali river estuary in Bangladesh. The decreasing order of metals concentration was Cu>Zn >Cr>Pb>Cd with the mean value of 2.6> 0.825 > 0.355 > 0.056 >0.003 mg/L, respectively. The results showed a significant seasonal variation of heavy metals concentration in water. Higher contamination occurred during post monsoon, while lower during the monsoon season. Among the all studied heavy metals Cu concentration was higher (2.6 mg/L) and lower (0.003 mg/L) concentration was Cd. Metal concentrations in water samples exceeded the safe limits of drinking water which indicated that the water from this estuarine river is not fully safe for using/drinking. The study area was not entirely polluted in terms of all metal concentrations. But level of metal concentration in polluted sites supposed risk to ecological health. The findings of present study recommended that continuous monitoring of water should be aimed to evaluate the risk which could help to maintain healthy coastal ecosystem and improve management strategy of this estuarine river.

Комплексная оценка экологического состояния участка трансграничной реки Нарвы

A comprehensive study of the ecological state on the transboundary Narva River (Russia –Estonia border) downstream of Ivangorod, Kingisepp District, Leningrad Region, was carried out. It included the determination of chemical indicators of pollution of the natural river water, with an emphasis on some heavy metals content in water, sediments and soft tissues of local filter-feeding mollusks; the latter were used as bioindicators of river pollution in this location. Zn was determined in maximum concentrations in bottom sediments, then Cu, to a lesser extent Pb, Cd and Ni. The coefficient of metal bioconcentration calculated in soft tissues of mollusks showed maximum for Zn and Cu, to a lesser extent for Pb, Cd and minimum for Ni. However, such values have no negative effect on local biota as shown by physiological testing of bivalves from study site. The functional assessment of bivalves by non-invasive cardiac rhythm recording made it possible to characterize their functional status and adaptive capabilities as good. The relative abundance of hydrocarbon-oxidizing bacteria in the digestive tract of mollusks from the Narva River has been determined as an indicator of environmental pollution by oil products. It was noted that the number of hydrocarbon-oxidizing bacteria does not exceed the values characteristic of the reference waters of the Eastern Gulf of Finland. Based on the totality of the studies, it was concluded that the river waters in the studied location can be characterized as slightly polluted and its ecological status as of a good quality.

Assessments of heavy metal contaminations of surface water and sediment of Pülümür Stream (Türkiye)

The primary considerations within aquatic ecosystems are water and sediment quality, rendering it imperative to assess their concentrations, pollution levels, origins, and ecological hazards. In this study, heavy metal concentrations in surface waters and sediments of the Pülümür Stream were investigated to assess the level, distribution, source of pollution and the associated human risks. Water and sediment samples from the river were collected monthly from February 2021 to January 2022 and examined using the Inductively Coupled Plasma Mass Spectrometry (ICP– MS) technique. Metal concentrations in the sediment followed a decreasing or derivative sequence of Fe > Al > Mn > Ni > Cr > Zn > Cu > Pb > As >Cd > Hg. The ecological indices of the stream water have low degrees of contamination by heavy metals. Igeo and EF showed that most of the sites are moderately to highly polluted due to Ni, and Cr, while PLI and PERI showed a progressive deterioration of the environment at site 9. Moreover, the modified hazard quotient (mHQ) indicates low ecological risk for Cu, Pb, Zn, Cd, Hg metals, while Ni, As and Cr reach high pollution at sediment sites. Pearson correlation analysis revealed that the presence of Zn, Cu, Pb, Hg, and Mn metals in the sediment analysis has a lithogenic source, and As, Ni, Cd, and Cr accumulate due to human activities, mainly domestic and agricultural irrigation wastes and mining wastes, all of which affect the aquatic environment. According to this study, more attention should be paid to the comprehensive monitoring of metals in the water and sediment for both aquatic biota and human risk of the Pülümür River.

Elevated Uptake and Translocation Patterns of Heavy Metals in Different Food Plants Parts and Their Impacts on Human Health.

Irrigation with contaminated wastewater is a common practice in cultivation of crops and vegetables in many developing countries due to the scarcity of available fresh water. The present study has investigated the transfer and mobilization trends of heavy metals in different crops and vegetables plants grown in contaminated soil and waterbody. The translocation patterns of metals from polluted sources into different organs of plants bodies such as roots and edible parts and associated health risks have been evaluated simultaneously. Total of 180 different environmental samples including food plants, agricultural soil, and irrigation water were collected and analyzed. Heavy metal concentrations (Fe, Ni, Mn, Pb, Cu, Cd, As) in water, soil, and different parts of crops and vegetable plants were compared with the permissible levels reported by FAO/WHO, EU, and USEPA. Different metals contents within the food plants were found to be in the order of Fe > Mn > Ni > Cu > Pb > Cd > As. Pollution load index (PLI) data indicate that soil is highly polluted with Cd as well as moderately contaminated by As and Cu. Bioconcentration factor (BCF) analysis showed excessive accumulation of some heavy metals in crops and vegetables. Target hazard quotient (THQ) and target carcinogenic risk (TCR) analysis data showed higher carcinogenic and non-carcinogenic risks for both adult and children from the consumption of metal-contaminated food items. The results of metal pollution index (MPI), estimated daily intake (EDI), and hazard index (HI) analyses demonstrated the patterns of metals pollution in different food plants.

Threat of heavy metal pollutants and parasites to freshwater fish with special reference to their risk of cancer to humans in Egypt

Understanding how pollution and parasite infection work together to stress their hosts' health raises the possibility of a danger to aquatic life and humans. This study examined two freshwater fish species, Clarias gariepinus, and Oreochromis niloticus, at El-Abbasa Fish farm in Sharkia Governorate of Egypt. to determine their heavy metal content, parasite frequency, and potential health risks. Parasitological investigations revealed higher parasite prevalence in C. gariepinus, with trematodes being the most prevalent. Histopathological examinations displayed severe alterations in infected fish, including gill necrosis, intestinal damage, liver degeneration, and muscle necrosis. Moreover, heavy metal analysis. Heavy metals levels in water, Fe, Zn, Pb, Cu, As, and Cd levels were 0.95 ± 0.04, 0.75 ± 0.03, 0.14 ± 0.02, 0.09 ± 0.01, 0.07 ± 0.01, and 0.03 ± 0.01 mg/L, respectively. Sediment samples showed Cd as the lowest (2.38 ± 0.94 μg/g dry wt. basis) and Fe as the highest (241.01 ± 6.39 mg/kg dry wt. basis). The sequence of heavy metal concentrations in both water and sediment was Fe > Zn > Pb > Cu > As > Cd. Significant differences were found among metals in water and sediment (p < 0.05). Heavy metal concentrations in fish tissues followed the order liver > muscles > gills > intestine Iron was the most abundant, while cadmium was the lowest is the order in which bio-accumulation factors (BAF) between water and fish tissues followed a descending order: BAF-Liver < BAF-Gills < BAF-Intestine < BAF-Muscles. The sequence of heavy metal accumulation in tissues was BAF-Fe > BAF-Pb > BAF-Cd > BAF-As > BAF-Cu > BAF-Zn, indicating varying degrees of accumulation across different metals and tissues and bio-sedimentation (BSF) of metals in fish tissues are the order of heavy metal concentration within tissues was BSF-Cd > BSF-As > BSF-Fe > BSF-Zn > BSF-Cu > BSF-Pb. Additionally, data were recoded to reflect histological changes in several fish organs. The estimated daily intake of heavy metals (EDI-HMs) was far lower than the permissible tolerated daily intake (PTDI) limits, which were set by international authorities at 70 kg of body weight. As the hazard index value is below 1, the THQ and HI associated with the consumption muscle of fish demonstrate negligible non-carcinogenic harm to residents' health. Contrarily, As, and Cd pose a cancer threat for kids and adults who eat muscular fish, and it needs to be viewed as a warning sign from the perspective of data indices and human health.

Assessment of Metal Concentration and Bioaccumulation Factor in Surface Water and Fishes Sampled From Four Creeks in the Bonny River Estuary, Niger Delta Region of Nigeria

The indiscriminate disposal of industrial and urban waste has added to the concerns of global water pollution. Anthropogenic activities and activities of oil companies (oil spills) have also contributed to the pollution of the aquatic ecosystem in the Niger Delta region of Nigeria. This study was therefore designed to evaluate the concentration of Iron, Nickel, Lead, Cadmium and Chromium in our surface waters and our marine life. Samples of surface water were collected into 50 cl sterile plastic bottles and labelled accordingly. Twenty medium-sized tilapia fishes from about a one-kilometre radius of each site were caught and also labelled accordingly. Water and fishes from each site were then kept in a cooler, iced and immediately transported to the laboratories for analysis for heavy metals after these fishes were homogenised using a blender. Atomic absorption spectrophotometer was used for the metal analysis. Standards were prepared using tracecert of each of the above-mentioned metals. The results of these study sites (Akpajo, Okujagu, Woji and Elelenwo) had high concentrations of metals. Fishes from all these sites also had high concentration of these metals. The trend of metal concentration in the surface water as follows: Okujagu–Pb&gt;Cr&gt; Cd&gt;Fe = Ni, Akpajo–Cd&gt;Fe&gt;Pb&gt;Cr&gt;Ni, Elelenwo–Pb&gt;Cr&gt;Fe&gt;Cd&gt;Ni, Woji–Cr&gt;Cd&gt;Pb&gt;Fe&gt;Ni. Results obtained also revealed the trend of metal concentration in fish muscles as follows: Okujagu–Pb&gt;Cr&gt; Cd&gt;Fe = Ni, Akpajo– Cd&gt;Fe&gt;Pb&gt;Cr&gt;Ni, Elelenwo–Pb&gt;Cr&gt;Fe&gt;Cd&gt;Ni and Woji–Cr&gt;Cd&gt;Pb&gt;Fe&gt;Ni. Fishes and surface water sampled from these four creeks in the Bonny estuary in the Niger Delta region of Nigeria had high concentrations of iron, nickel, cadmium, chromium and lead in relation to their concentration in surface water. The results of this study revealed that metal concentration in surface water had some relative effect on their concentration in the fishes. This, therefore, means consumption of these fishes may lead to the accumulation of these metals in man to a toxic concentration. This may be one of the reasons for the increase in some heavy metal-related health issues (diabetes, renal diseases) in this region.

A feasible approach to measure metal concentrations in drill hole waters on site for mineral exploration

The new technologies used in the green transition towards carbon-free societies typically demand extensive use of metals. This leads to a heavily growing need for exploration and extraction of ore deposits. Exploration can be facilitated by measuring metal concentrations in ground and surface waters carrying trace concentrations of metals leached from nearby deposits. Currently, measuring metal concentrations in water is slow and expensive and it cannot be done on-site, which hinders the discovery of new ore deposits. To address this challenge, we have developed a method to collect and concentrate the dissolved metals in a solid filter and measure the metal concentrations directly from the filter with a portable X-ray fluorescence spectrometer. The permeable filter is made of mesoporous silicon modified with bisphosphonates. Two types of adsorbing materials for the filters were prepared based on scalable production methods: i) regenerative etching of metallurgical grade silicon powder, and ii) magnesiothermic reduction of silica from barley husks. Empirical calibrations were prepared in a concentration range of 10–200 μg/L for Mn, Co, Ni, Cu, Zn, and Pb using water samples prepared by spiking well water with standard metal solutions. Both filter types were tested for their ability to adsorb metals from the real water samples taken from drill holes. The developed system was able to detect metal concentrations down to 12 μg/L (ppb) showing its potential for on-site measurements of dissolved metals in water samples, which could be feasible in the discovery of new mineral deposits. This innovation enables smart sampling during exploration and provides real-time information on metal concentrations in water.

Water Quality Assessment and Heavy Metal Levels in Mudskipper (Periophthalmus Papilio), Sediments and Water of Mangrove Swamps, Rivers State, Nigeria

A study was conducted to determine the physicochemical parameters of surface water and heavy metal concentrations in the mudskipper (Periophthalmus papilio) fish, sediments, and water collected from the Ikpukulu, Kalio, and Ogoloma swamps of Okrika Local Government Area, Rivers State, Nigeria and analysed using standard methods. All samples were collected for six months from three stations in 2023. The results indicate that pH and temperature values were significantly lower across stations in terms of physicochemical properties than standards. However, there was a significant increase in electrical conductivity, total dissolved solids, and salinity. Ikpukulu had the highest EC (1917 uS/cm), while Kalio had the highest salinity (333.3 ppm). All stations had significant decreases in dissolved oxygen (DO) and biological oxygen demand (BOD), with Ogoloma having the lowest values (DO: 3.2 mg/L, BOD: 2.9 mg/L). Copper and chromium levels were significantly higher than the standards in all stations, while cadmium levels were not significantly different from those in the standards. As compared with the standards, copper levels in water samples were considerably higher, especially in Ogoloma (2.03 mg/kg). Ogoloma had a higher concentration of chromium. Cadmium levels decreased significantly at all stations for the mudskipper (P. papilio). The copper levels in Ogoloma and the chromium levels in Ikpukulu were significantly higher than those in standards. The results of the study suggest an increase in heavy metal concentrations in the mangrove swamp region, emphasising the need for proactive measures to mitigate activities that may adversely affect the aquatic ecosystem and the communities that depend on it.

Toxic Element Contamination Sources in the Surface and Groundwater of the Elbrus Region: Geochemistry and Health Risks

The region surrounding the Elbrus volcano in the Great Caucasus is a popular tourist destination, home to native people and an area of the richest ore mineral resources. Based on the chemical composition of surface water, mineral, and groundwater in the Elbrus area, as well as statistical and thermodynamic calculations, waters with high concentrations of Mn, Cu, Zn, Mo, Ba, W, Pb, and As were identified, possible mineral phases that may lead to these metal concentrations in water were estimated, and risks to human health were assessed. Two main sources of surface water pollution have been identified: (1) water from tailings that are enriched due to oxidation of sulfide minerals is considered a source of As (181 µg/L) and Mo (2070 µg/L) pollution in the area of the Tyrnyauz W-Mo deposit; and (2) CO2-rich waters of deep horizons discharge on the earth surface with high concentrations of As (828 µg/L) and W (504 µg/L). It has been shown that compared to all toxic elements studied, only Mo and As have adverse non-carcinogenic effects on adult health. The estimated carcinogenic risk of As in the mine area was 1.7 × 10−3 and exceeded the generally accepted range of 10−4 to 10−6. In order to minimize the health risks, regular monitoring of water quality is required when mining activities on the Tyrnyauz W-Mo deposit are renewed.

Appraisal of pollution levels and non-carcinogenic health risks associated with the emergence of heavy metals in Indonesian community water for sanitation, hygiene, and consumption

Excessive heavy metal concentrations in water can pose a threat to human health. The research analyzed 160 groundwater samples used for hygiene and sanitation, of which 62 were used for consumption, and 98 other types of drinking water were analyzed. The research findings indicate that 6% of groundwater for hygiene and sanitation and 13% of drinking water (7.8% groundwater, 5.2% refill water) were deemed unfit for use due to elevated concentrations of certain heavy metals surpassing the maximum limits. As, Cd, Co, Hg, Mn, and Pb were detected in several drinking water samples deemed unsuitable for consumption. Several heavy metals suspected to originate from natural sources are Co, Fe, Mn, As, and Zn, while Pb, Cd, Hg, and Co are suspected to have anthropogenic sources. Only arsenic exposure through the ingestion pathway posed a non-carcinogenic health risk to the local population. Children were found to be more susceptible than adult males and females. The estimated average non-carcinogenic risk levels based on the water sources were refill water > well water > rainwater > spring water. Therefore, it is essential to monitor raw water sources at refill water depots in the study area and implement policies related to the quality of raw water sources, technology maintenance processes, and the quality of processed water from refill water depots. Additionally, the community should be educated about household-scale water treatment to minimize health risks and consider using untreated well water and rainwater for consumption.

Heavy metals assessment for sustainable management in estuaries of Ba Ria - Vung Tau province

Heavy metal concentration in the aquatic environment of estuaries is a significant environmental concern with potential consequences for ecosystems and human health. Heavy metals are naturally occurring elements that can enter aquatic environments through both natural processes and human activities. The interplay between natural processes and human activities, particularly urbanization and industrialization, often exacerbates heavy metal pollution in aquatic ecosystems. Some of the most common heavy metals of concern in estuarine pollution include arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), zinc (Zn), and iron (Fe). Based on the results of two surveys in rainy and dry seasons, the paper aims to assess the concentrations of heavy metals in the estuarine environment of Ba Ria - Vung Tau Province, Vietnam, to understand the extent of contamination and its potential impacts on the ecosystem and human health. The average concentrations As, Cd, Hg, Pb, Zn, and Fe were 2.01, 0.024, 0.028, 1.63, 4.71, and 492.9 µg/L in water, and 6.70, 0.175, 0.060, 11.78, 41.94, and 3,108.9 mg/kg in sediment, respectively. Heavy metal concentrations in water have an increased trend during the rainy season. In contrast, values in sediment exhibit an opposite pattern, which can be explained by various environmental factors and processes. For water and sediment quality, individual metals, and overall metal contamination levels (the contamination factor - Cf, contamination degree - Cd, and metal pollution index - MPI) may appear to be low, whereas the assessment of the combined effects of multiple metals (Metal quality index - MI &gt; 1) indicates that there is a potential risk to aquatic life in the estuaries. This assessment may underscore the importance of considering not only individual metal concentrations but also their cumulative effects when evaluating water and sediment quality and making decisions regarding protecting aquatic ecosystems. Further investigations and measures may be needed to mitigate potential harm to aquatic organisms and for sustainable management in estuaries.

Heavy metal contamination through wastewater irrigation on the soil and vegetables: Impact on the nutrient content and health risks ​

The use of wastewater irrigation may contribute to the metal accumulation, and reduction of nutrient level of vegetables, which would then have an adverse effect on human health. Therefore, in the present study we investigated heavy metals contamination and its impact on nutrient quality of vegetables and health risk. The study was conducted from the agricultural fields of Varanasi distinct during the period from March 2022 to June 2023 and all the laboratory work was carried in the department of Botany, Banaras Hindu University. Heavy metal concentrations in water, soil, and vegetable samples were measured using an atomic absorption spectrophotometer. The physiochemical property (pH), daily intake of metal, metal pollution index and health quotient were also calculated according to the published protocols. All heavy metal were found in higher concentrations in the wastewater irrigated soil that control site. The Lohta site had the highest concentration of heavy metals in the vegetables, followed by Dinapur, and least at control site (BHU). The highest concentration of metals (Cu, Zn, and Pb) were found in the leafy vegetables (S. oleracea and A. esculentus) whereas lowest in fruity vegetables (P. vulgaris). The rise in the Metal Pollution Index (MPI) also provided evidence for the greater metal content of these vegetables. The S. oleracea was found to have the highest DIM (0.061 g/g) while P. vulgaris had the lowest (0.007 g/g). HQ values of these metals were found greater than one ( greater than 1) for both children and adults on the ingestion of the vegetables of wastewater irrigated sites. Further, nutrient contents (Na, Mg, Ca) were also declined in the vegetables of wastewater irrigated site when compared to control site. These findings suggest that the consumption of such vegetables leads to compromised health and might be associated with severe health risk in the human.

Assessment of heavy metals in sediments and water accumulated by effects shipwrecks in Shatt Al-Arab River, southern Iraq

In this study, the total concentration of seven heavy metals (Cd, Cu, Fe, Pb, Mn, Ni, and Zn) in sediment and water was taken to determine how much the environment is impacted by rising levels of heavy metals that are not naturally occurring in five stations representing the large shipwrecks in Shatt Al-Arab River in Basra South Iraq by using atomic absorption. The heavy metals concentration in the five sediment stations is ordered as follows: Fe>Mn>Ni>Zn>Cu>Cd> Pb. While, the heavy metals concentration in the five water stations is ordered as follows: Fe>Ni>Mn>Cu>Pb>Zn>Cd. The current results of the study indicate that the concentrations of Cd, Fe, and Pb (slightly contaminated) metals in water are higher than the Iraqi standards (Iraqi standards for drinking water) and international standards (WHO, U.S. EPA, E.U.). An increase in heavy metal concentrations is attributed to the raw materials from which sunken ships are made near stations and these ships being exposed to military bombardment. The level of pollution in the sediment was assessed by employing the Geo accumulation index (I-geo), Contamination factor (CF), and Enrichment factor (EF). The calculated results of I-geo indicate that Cd can be considered to be moderate – strongly polluted except S5 considered strong to extremely polluted. However, Cu, Fe, Pb, Mn, Ni, and Zn showed almost unpolluted levels across all stations. The CF values indicate that this environment is very highly contaminated with Cd, while CF values for Cu, Fe, Pb, and Mn display low contamination. while CF values for Ni are moderate contamination except for S1 is low contamination. The pollution level for Zn is S1and S5 is low contamination and S2,3,4 is moderate contamination. The EF values refer to Cd at S5 indicating extremely severe enrichment and other stations refer to severe enrichment and minor enrichment for Fe, Mn, Ni, and Zn. Copper (Cu) has minor enrichment at S2 but no enrichment at the other stations. Conversely, Lead (Pb) shows no enrichment at any of the stations.

Adsorption of Heavy Metals on Alkali-Activated Zeolite Foams.

Elevated concentrations of heavy metals in natural waters can cause significant ecological problems. It is therefore essential to ensure their removal from any water discharged into the environment immediately, especially in case of an accident, where there is a risk of releasing large quantities or high concentrations. The aim of this paper is to test a newly developed adsorbent for the removal of heavy metals from aqueous solutions-in particular, it is very fast adsorption, and thus efficiency, during clean-ups. The alkali-activated foamed zeolite adsorbent was laboratory-prepared and -tested in both batch and flow-through arrangements on single and multi-component solutions and compared with natural zeolite. The experimental setup for batch adsorption consisted of a set of samples and solutions containing iron, cobalt, manganese, zinc and nickel. The samples were put on a horizontal shaker with a 500 mg adsorbent loading in a 50 mL solution. The column adsorption experimental setup consisted of a glass column with an inside diameter of 15 mm and a bed length of 165 mm. A measured amount of each adsorbent was added to the column to achieve a filter fixed-bed height of 160 mm. The high efficiency of the tested adsorbent on various heavy metals was confirmed. The adsorbent has a high potential for use in decontamination processes, water protection and landscape revitalization. Due to its rapid precipitation and subsequent fixation of metal cations in the form of insoluble oxide or hydroxide, it can be used as an emergency adsorbent, the great advantage of which is its low production cost and natural origin.

Chelated- and nano iron fertilization affects nutrient uptake and translocation in fresh market tomatoes

Our study aimed to evaluate the effects of nano and chelated Fe fertilization on nutrient and heavy metals uptake and their translocation from soil to root, stem, leaf, and fruits of fresh market tomatoes (Solanum Lycopersicon, cv. Sunbrite). A completely randomized design in a factorial experiment, with two Fe sources (nano vs. chelated) applied at 0 (control), 10, 20, and 40 mg/L via drip-irrigated plasticulture, was conducted. Nutrient and heavy metals concentrations in soil, water, tomato roots, stems, leaves, and fruits were determined. Soil had higher K, Fe, Ca, Mg, P, and Mn but lower Ni, Cd, and Cr concentrations. The P, K, Fe, Cu, Mn, and Na concentrations in the roots were significantly affected by both nano and chelated Fe fertilization; however, without following a consistent pattern. Averaged across the Fe treatments, K, Ca, Mg, Fe, and P that translocated from the soil were dominated in the roots, stems, and leaves. The nutrient translocation order, from roots to fruits in response to Fe fertilization, was nano Fe (40%) > chelated Fe (37%) > control (23%). Based on the treatment index values calculated across treatments, it is evident that Fe fertilization plays a pivotal role in nutrient uptake and translocation. The use of chelated Fe at a concentration of 20 mg/L had a pronounced effect on improving the nutritional quality of the tomatoes and, by extension, their associated public health benefits. In conclusion, the chelated Fe (20 mg/L) stands out as the most preferable and effective Fe fertilization for tomatoes.

Plant Growth-Promoting Bacteria (PGPB): A Potent Source of Heavy Metal Stress Management in Plants

Heavy metals or metalloids are toxic elements found throughout the crust of the earth’s surface. The gradual increase of heavy metal concentration in soil and water due to some natural and anthropogenic activities like application of agrochemicals, waste disposal, industrial activities, mining, smelting, lead-based paints, etc cause stress to the local vegetation. Soil microorganisms play a critical part in the remediation of heavy metal contaminated soil and thereby exert direct or indirect promotion to plant growth. Plant growth-promoting bacteria (PGPB), specially the Plant growth-promoting rhizobacteria (PGPR), are a natural, sustainable, and eco-friendly solution for mitigating stress challenges. They can boost plant growth by alleviating heavy metal toxicity through various mechanisms such as metal sequestration, metal immobilization, and production of metal chelating compounds, which reduce metal toxicity and enhance plant growth. This review summarizes the effect of heavy metal stress on plants, the response of plants to heavy metal stress, mechanisms involved in metal stress tolerance by soil bacteria, and their application in managing heavy metal stress in plants.

Appraisal of trace metals toxicity and human health risk using a novel approach in wastewater of four gas fields, Bangladesh

The objective of this study is to assess the toxicity of trace metals (TMs) and associated environmental, ecological and health risks in the gas fields located in the Sylhet region of Bangladesh. Gas well-produced water, gas field discharge water, and drinking water surrounding the gas fields were collected for analysis. This study analyzed carcinogenic and noncarcinogenic TMs such as Cr, As, Co, Cd, Fe, Ni, Mn, Zn, and Pb, as well as physical parameters pH and EC in the collected samples using various instruments. The TMs were measured using Atomic Absorption Spectrometer (AAS), Flame AAS and physical parameters were evaluated using portable water multiparameter. The Fe and EC concentrations in produced and discharged water samples were incredibly high. The average concentrations of TMs in produced water samples during the summer and rainy seasons were found to be Fe > Mn > Zn > Ni > Co > Cu > Cr > Pb > As > Cd. The observed metal concentration in discharge water was higher during the summer than in the rainy season. Most samples met national and international standards for trace elements, while a few samples exceeded the threshold value.The Heavy Metal Evaluation Index (HMEI) results indicate that most produced water is highly polluted, while discharge and drinking water are moderate to lightly polluted. The Environmental Pollution Index (EPI) indicates environmental pollution for some produced water samples, while it indicates a moderate to low risk for discharge and drinking water samples. The source of trace metals (TMs) was determined using positive matrix factorization. However, all water samples have an ecological risk index of less than 150, indicating lower risk. Furthermore, the Heavy Metals Toxicity Load (HMTL) was below the allowable toxicity load for all water samples, indicating minimal contamination in the studied water. The non-cancer hazard score (HI) of the studied HMs is more significant for children and females than males. The cancer risk from Ni is a concern, while the cancer risk from Cd and Cr is also a matter of concern. In the end, policymakers can utilize this study's findings to monitor, and control produced water contamination.

Occurrence, distribution, sourceapportionment, ecological and health risk assessment of heavy metals in water, sediment, fish and prawn from Ojo River inLagos, Nigeria.

The study investigates the occurrence and bioaccumulationof heavy metals in water, sediment,fish, and prawn from the Ojo River with a view to identify the source of origin and the associated ecological and human health risks. The result shows that heavy metal concentrations in water [As = 0.010, Cd = 0.001, Cr = 0.041, Cu = 0.019, Co = 0.050, Fe = 0.099, Pb = 0.006, Ni = 0.003, and Zn = 0.452(mg/L)]were within theacceptable limits. The heavy metals in the sediment [As = 0.050, Cd = 0.287, Cr = 0.509, Cu = 0.207, Co = 0.086, Fe = 33.093, Pb = 0.548, Ni = 0.153 and Zn = 4.249 (mg/kg)]were within their respective background levels orearth's crust and theTEL and PEL standardlimits. The bioaccumulation ofheavy metals in fish and prawntissues are in this hierarchical form: Fe > Zn > Cu > Cr > Ni > Co > Pb > Ar > Cd and Fe > Zn > Cu > Cr > Pb > Ar > Ni > Co > Cd, respectively. The bioaccumulation factors of heavy metals in fishranged from 0.893 - 16.611 and 1.056 - 49.204 in prawn, which were higher than the biota-sedimentation factors (BSAF) values, inferring that the fish and prawns of this study ingested heavy metals highly from watercolumn. The aggregated BSAF scores (fish = 5.584 and prawn = 9.137) showed that these organisms are good concentrators of heavy metals in sediments. The water quality index and other pollution indices (Singlepollutionindex, Heavymetal assessment index, and Heavy metalpollutionindex) demonstrates slightlycleanwater, with a moderate level of contamination. The HI values of heavy metals in water, fish, and prawn were lower than 1, implying non-carcinogenic risk in children or adults. The ADD and EDI values of the metals were within their respective oral reference doses (RfD). The TCR values showed that exposure to water, either by ingestion or dermal absorption and the consumption of P. obscura and M. vollenhovenii from the Ojo River would not induce cancer risks in people, though As, Cr, Cd, and Pb showed carcinogenic potentials. The sediment contamination indices such as CF, mCd, EF, and Igeo showed a moderate level of pollution. The ecological risk values (NMPI, mCd = 0.068, PLI = 0.016, and R.I = 86.651) of heavy metals implies "no-moderate risk" except for Cd, which showed high risk. The ecotoxicologicalparameters, m-PEL-Q (0.024) and m-ERM-Q (0.016) denotes low contamination and no probability of acute toxicity. The CV analysis showed high dispersions and variabilities in the distributions of the heavy metals in water. Other source analyses (Pearson's correlation matrix, PCA, and HCA) showed that both natural processes and anthropogenic activities are responsible for the occurrence of heavy metals in water and sediment from the Ojo River.

Assessment of the status of selected heavy metals in water, sediments and a fish species (Oreochromis niloticus) of commercial value in Lake Nakuru with a focus on human health risks

AbstractThe present study presents selected water quality parameters and the levels of heavy metals in water, sediments and Nile tilapia (Oreochromis niloticus) of Lake Nakuru. Nine sediments and nine water samples, as well as 30 specimens of Nile tilapia, were collected from the northern part of the lake. Physical parameters were measured in situ using multiple probes and metres. Heavy metals were analysed using an atomic absorption spectrophotometer (AAS). The pH, dissolved oxygen concentration, temperature, salinity and electrical conductivity ranged from 9.52 to 9.72, 4.58 to 8.62 mg/L, 23.40°C to 25.7°C, 2.39‰ to 2.81‰ and 4470–5226 μs/cm, respectively. Heavy metal levels (mean ± SD) were generally low in the water samples. Chromium values ranged between 7.16 and 9.19 mg/kg dw in sediment samples, and between 3.7 and 13.06 mg/kg dw in fish samples. Lead values ranged between 12.5 and 31.04 mg/kg dw in sediment samples and 4.06 and 9.95 mg/kg dw in fish samples. Arsenic values ranged between 9.5 and 21.7 mg/kg dw in sediments and below detectable limit to 2.11 mg/kg dw in fish samples. Mercury values ranged between .14 and .31 mg/kg dw in sediment samples and .12 and .35 mg/kg dw in fish samples. Cadmium was the only heavy metal concentration that was below the detection limit in the three matrices. Significant differences were observed for some heavy metal concentrations in water, sediments and fish across sites (p &lt; .05). The levels of lead and chromium in fish were above the East African Standard, World Health Organization and European Union limits. The results of the present study recommend a possible reclassification of the lake, an immediate ban on fish harvesting and consumption from Lake Nakuru and a policy intervention on the fishery and pollution management.