Increasing Metal Concentration Research Articles

Evaluation of physicochemical parameters and heavy metal concentrations in shrimp (<i>Penaeus monodon</i>), sediment and surrounding water of the Mangrove Swamps, Rivers State, Nigeria

The study focused on the evaluation of the physiochemical and heavy metal concentration in shrimp (P. monodon), sediments and surface water of Ikpukulu, Kalio, and Ogoloma swamps in Okrika Local Government Area, Rivers State, Nigeria. The following parameters were examined: temperature, potential hydrogen, electrical conductivity, salinity, dissolved oxygen, biochemical oxygen demand, total dissolved oxygen, temperature, and the content of heavy metals (Cd, Cu, and Cr) in surface water, sediments, and shrimp. The pH values (p > 0.05) did not significantly differ amongst the stations. The three sampling station readings of pH were below WHO and FEPA (standards). The temperature data from the three stations did not show any significant differences (p > 0.05), but when compared to the standards, all of the readings were much lower. Result from Ogoloma showed that it had lowest electrical conductivity ratings of the three stations, although overall, the values were higher than the norms. At Kalio, the highest Total Dissolved Solids value (9348.6 ± 67 mg/L) was recorded. When compared to the standards, the salinity values of the three stations were noticeably higher. For Biological oxygen demand, there was no significant (p>0.05) difference between the three stations, but comparing the values to the standards they were all significantly (p>0.05) lower. Heavy metal analysis showed that in the sediment, Copper concentration at Ogoloma was significantly (p>0.05) higher among the three metals in the three stations. Copper and chromium concentrations in the three stations were much higher than the standard. Among the three metals found in the water at the three stations, copper had the highest quantities; the content of copper in Ogoloma was noticeably greater than the standard. Of the threelocations, Ogoloma exhibited a noticeably greater concentration of copper for Shrimp. Thefindings highlight the necessity for preventative action by pointing to an increase in heavy metalconcentrations in the Mangrove swamp area.

Exploring the combined effect of heavy metals on accumulation efficiency of Salix alba raised on lead and cadmium contaminated soils

The present study illustrated that Salix alba can accumulate high level of Pb and Cd in different plant parts, with maximum accumulation in roots followed by stem and leaves in the order Cd > Pb > Cd + Pb. The phytoremediation evaluation factors such as bioconcentration factor (BCF) and translocation factor (TF) was higher for Cd over Pb in all plant parts, further the BCF for both Pb and Cd was maximum in root (BCF > 1) followed by stem and leaves. Higher accumulation of Cd over the Pb was observed inside the plant tissues due to Cd mimics with other elements and gets transported through respective transporters. The combined treatment of Pb and Cd affected the bioaccumulation at every treatment level suggesting the negative effect among both elements. Higher survival rate (>85%) was recorded up to 200mgPb/kg and 15mgCd/kg, while further increase in metal concentration reduced the plant efficiency to remediate contaminated soils, hence results in declined survival rate. The FTIR analysis revealed that Pb and Cd accumulation in plants induced changes in carboxy, amino, hydroxyl and phosphate groups that ultimately caused alteration in physiological and biochemical processes of plant and thus provided an insight to the interaction, binding and accumulation of heavy metals.

A research on the effect of plasma spectrum collection device on LIBS spectral intensity

Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information. To overcome this limitation, this study presents a novel method for acquiring plasma spectral information from various spatial directions. A parabolic-shaped plasma spectral collection device (PSCD) is employed to effectively collect more spectral information into the spectrometer, thereby enhancing the overall spectral intensity. The research objects in this study were soil samples containing different concentrations of heavy metals Pb, Cr, and Cd. The results indicate that the PSCD significantly enhances the spectral signal, with an enhancement rate of up to 45%. Moreover, the signal-to-noise ratio also increases by as much as 36%. Simultaneously, when compared to the absence of a device, it is found that there is no significant variation in plasma temperature when the PSCD is utilized. This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity. Consequently, a concentration-spectral intensity relationship curve is established under the PSCD. The results revealed that the linear fitting R 2 for Pb, Cr, and Cd increased by 0.011, 0.001, and 0.054, respectively. Additionally, the limit of detection (LOD) decreased by 0.361 ppm, 0.901 ppm, and 0.602 ppm, respectively. These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration. Hence, the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.

Changes in properties of reclaimed-mine soil, plant growth, and metal accumulation in plants with application of coal fly ash and empty fruit bunches of oil palm

Reclaimed-mining soil (RMS) is characterized by low fertility, acidic pH, and high heavy metal contents. As a result, adding amendments becomes essential to support plant growth. Therefore, this research measured alterations in the characteristics of RMS, plant growth, and metal accumulation in plants with the co-application of coal fly ash (CFA) and empty fruit bunches of oil palm (EFBOP). In the first experiment, various levels of CFA (0, 75, and 150 Mg ha-1) and EFBOP (0, 25, and 50 Mg ha-1) were added to the RMS and then incubated at 70% water holding capacity for 45 days to determine their effect on changes in soil properties. In the second experiment, four treatments: control, CFA, EFBOP, and CFA+EFBOP were tested in the greenhouse to quantify their effects on the growth and metal accumulation of plants. Results of the study showed that the co-application of CFA and EFBOP significantly affected bulk density, pH, mineral nitrogen (NH4+ and NO3-), available phosphorus, and exchangeable Ca and Mg in RMS. CFA application increased exchangeable Al by 82-160%, while EFBOP resulted in a decrease of 24-119%. CEC decreased with CFA application and increased with the use of EFBOP. Plant growth increased with the co-application of CFA and EFBOP. The addition of CFA to soils results in increasing metal contents in plant tissue; however, the presence of EFBOP reduced the concentrations of metal in plant tissue. These results highlight the potential of CFA and EFBOP, which are industrial and agricultural wastes, as valuable soil amendments.

Fertility and heavy metal pollution in silage maize soil irrigated with different levels of recycled wastewater under conventional and no-tillage practices

AbstractIrrigation with recycled domestic wastewater has been known to obtain positive effects on improving soil fertility, but it may also become a risk factor in case of causing an increase in soil salinity and/or heavy metal concentration of soil. No-tillage can retain soil moisture, helping to reduce irrigation water necessity, and thus lower amounts of heavy metals and salts are added to soil under wastewater irrigation conditions. The objective of this study was to analyze the effects of wastewater irrigation at different levels of on silage maize cultivation under conventional tillage and no-tillage conditions by comparing to full irrigation with fresh water. The two-year experiment was planned according to the split-plots design in the random blocks with three replications. The results indicated that full irrigation with wastewater increased soil salinity, organic matter content, total nitrogen, plant available phosphous, exchangeable cations, exchangeable sodium percentage and soil essential and non-essential heavy metal contents, but decreased soil pH and lime content. Increasing rates in organic matter content, total nitrogen, plant available phosphorus and exchangeable potassium were higher, but in electrical conductivity, and heavy metal accumulation were lower in soil under no-tillage as compared to conventional tillage. Contamination and enrichment factors and geographic accumulation index showed that non-essential heavy metal contamination due to cadmium and nickel, increased in full irrigation with wastewater. Irrigation with wastewater also increased heavy metal accumulation in silage maize. No-tillage can be a recommendable water management practice considering that the risks of soil salinity and heavy metal accumulation can be reduced and that soil fertility can be increased. Also, in reducing the risk of accumulation of cadmium and nickel in soil, 33% deficit irrigation with wastewater can make no-tillage more available.

Characterization and childhood exposure assessment of toxic heavy metals in household dust under true living conditions from 10 China cities

Health hazards caused by metal exposure in household dust are concerning environmental health problems. Exposure to toxic metals in household dust imposes unclear but solid health risks, especially for children. In this multicenter cross-sectional study, a total of 250 household dust samples were collected from ten stratified cities in China (Panjin, Shijiazhuang, Qingdao, Lanzhou, Luoyang, Ningbo, Xi'an, Wuxi, Mianyang, Shenzhen) between April 2018 and March 2019. Questionnaire was conducted to gather information on individuals' living environment and health status in real-life situations. Multivariate logistic regression and principal component analysis were conducted to identify risk factors and determine the sources of metals in household dust. The median concentration of five metals in household dust from 10 cities ranged from 0.03 to 73.18 μg/g. Among the five heavy metals, only chromium in household dust of Mianyang was observed significantly both higher in the cold season and from the downwind households. Mercury, cadmium, and chromium were higher in the third-tier cities, with levels of 0.08, 0.30 and 97.28 μg/g, respectively. There were two sources with a contribution rate of 38.3 % and 25.8 %, respectively. Potential risk factors for increased metal concentration include long residence time, close to the motorway, decoration within five years, and purchase of new furniture within one year. Under both moderate and high exposure scenarios, chromium showed the highest level of exposure with 6.77 × 10−4 and 2.28 × 10−3 mg·kg−1·d−1, and arsenic imposed the highest lifetime carcinogenic risk at 1.67 × 10−4 and 3.17 × 10−4, respectively. The finding highlighted the priority to minimize childhood exposure of arsenic from household dust.

Recovery of excess sulfuric acid in the lithium-ion batteries recycling process

Excess sulfuric acid which is needed for the leaching process of spent lithium-ion batteries is commonly neutralized generating significant waste streams. This research aims to extract and recover sulfuric acid using tri-n-octylamine as an extraction agent. 1-octanol, 2-ethylhexanol, and tributyl phosphate are investigated as synergetic extractants and phase modifiers. An equilibrium study is carried out on both, sulfuric acid and leachate. The equilibrium constant and the stoichiometric coefficient for the overall equilibrium reaction are determined by slope analysis. The enthalpy and Gibb’s enthalpy are studied by investigation of the effect of temperature. Regarding the experiments using leachate, the co-extraction of aluminum, cobalt, copper, iron, lithium, manganese, and nickel is studied, too. Moreover, the co-extraction of water is investigated as a significant increase in metal concentration in the raffinate is observed.

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.

Competitive Adsorption of Cd(II) and Zn(II) on Biochar, Loess, and Biochar-loess Mixture

Combined heavy metal contamination in soil is a common phenomenon. Biochar amendment into the soil is considered to be an alternative for immobilization remediation of soil contaminated with heavy metals due to its adsorption and alkalization. However, much attention has been paid to the adsorption and immobilization of single heavy metals by biochar. In this paper, the competitive adsorption of Cd(II) and Zn(II) on biochar derived from cotton straw and pig manure at 500℃ (BCS500 and BPM500), loess and biochar-loess mixtures were investigated using the batch equilibrium method. The results showed that the adsorption capacities of biochars, loess, and biochar-loess mixtures to Cd(II) and Zn(II) in the mixed Cd-Zn systems increased with the increase of initial metal concentrations of Cd(II) and Zn(II). The adsorptive capacities of BCS500 and BPM500 to Cd(II) in mixed Cd-Zn system were 33% and 35% less than those in the single Cd(II)systems, while the adsorptive capacities to Zn(II) were 62% and 56% less than those in the single Zn(II) systems. The adsorptive capacities of loess to Cd(II) and Zn(II) in mixed Cd-Zn systems were 29% and 55% less than those in the single metal systems. The adsorptive capacities of loess-BCS500 (LBCS) and loess-BPM500 (LBPM) to Cd(II) in mixed Cd-Zn system were 40% and 38% less than those in the single Cd(II) systems, while the adsorptive capacities to Zn(II) were 63% and 60% less than those in the single Zn(II)systems. Moreover, the competitive adsorptive capacity of Cd(II) is greater than that of Zn(II). It can be seen that when heavy metal pollution with similar nature of multiple elements exists in soil, the amount of adsorbent should be increased to resist the possible weakened adsorption caused by competitive adsorption in order to guarantee an effective absorption treatment.

Cardiotoxicity and ROS Protection Assessment of three Structure-Related N-Acylhydrazones with Potential for the Treatment of Neurodegenerative Diseases.

The senescence process is associated with accumulated oxidative damage and increased metal concentration in the heart and brain. Besides, abnormal metal-protein interactions have also been linked with the development of several conditions, including Alzheimer's and Parkinson's diseases. Over the years we have described a series of structure-related compounds with different activities towards models of such diseases. In this work, we evaluated the potential of three N-acylhydrazones (INHHQ: 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone, HPCIH: pyridine-2-carboxaldehyde isonicotinoyl hydrazone and X1INH: 1-methyl-1H-imidazole-2-carboxaldehyde isonicotinoyl hydrazone) to prevent oxidative stress in cellular models, with the dual intent of being active on this pathway and also to confirm their lack of cardiotoxicity as an important step in the drug development process, especially considering that the target population often presents cardiovascular comorbidity. The 8-hydroxyquinoline-contaning compound, INHHQ, exhibits a significant cardioprotective effect against hydrogen peroxide and a robust antioxidant activity. However, this compound is the most toxic to the studied cell models and seems to induce oxidative damage on its own. Interestingly, although not possessing a phenol group in its structure, the new-generation 1-methylimidazole derivative X1INH showed a cardioprotective tendency towards H9c2 cells, demonstrating the importance of attaining a compromise between activity and intrinsic cytotoxicity when developing a drug candidate.

Evaluation of heavy metals contamination in Rabbit Fish (Signus Sutor) from selected landing sites in Zanzibar, Tanzania

The increase of heavy metals concentrations in aquatic and terrestrial environments and their toxicity is of global concern. The bioaccumulation of toxic metals in fish poses a serious risk to human health when consumed. This study assessed the quality of Rabbit fish (Signus Sutor) and their associated health risks from four landing sites (namely Malindi, Mazizini, Kizimkazi and Matemwe) in Zanzibar. The concentrations of toxic metals, including Lead (Pb), Cadmium (Cd), Copper (Cu), Chromium (Cr), Nickel (Ni), and Arsenic (As), in the fish muscle were scrutinized using inductively coupled plasma optical emission spectrometry (ICP-OES). The detected mean concentration (mg/kg) of Pb, As, Cr, Cd, Cu, and Ni at Malindi were 0.25±0.14, 2.22±0.44, 0.02±0.02, 0.01±0.00, 0.02±0.02 and 0.00±0.00 respectively; at Kizimkazi were 0.39±0.39, 2.30±0.44, 0.11±0.01, 0.07±0.04, 0.17±0.13 and 0.15±0.04 respectively: at Matemwe were 0.38±0.12, 0.52±0.14, 0.04±0.02, 0.05±0.01, 0.65±0.21 and 0.09±0.03 respectively; and Mazizini were 0.21±0.12, 5.56±1.37, 0.02±0.02, 0.03±0.01, 0.05±0.02 and 0.15±0.05 respectively. The mean concentration levels detected for all the elements in the fish gathered from all four landing sites were below international and local maximum (FAO/WHO) permissible limits for human consumption, except for Arsenic (As) and lead (Pb). The study also investigated the relationship between fish size and metal concentration which shows a positive correlation for Cu and Ni. However, it was negative for the remaining metals, possibly due to ecological and metabolic differences. The study emphasizes the necessity for regular monitoring of the marine environment and enforcement of hygienic regulations, as well as the treatment of land-based pollutants before they are discharged into the marine environment to protect fish quality.

Determination of Soil Contamination at the Wildland-Urban Interface after the 2021 Marshall Fire in Colorado, USA.

Wildfires at the wildland-urban interface (WUI) are increasingly common. The impacts of such events are likely distinct from those that occur strictly in wildland areas, as we would expect an elevated likelihood of soil contamination due to the combustion of anthropogenic materials. We evaluated the impacts of a wildfire at the WUI on soil contamination, sampling soils from residential and nonresidential areas located inside and outside the perimeter of the 2021 Marshall Fire in Colorado, USA. We found that fire-affected residential properties had elevated concentrations of some heavy metals (including Zn, Cu, Cr, and Pb), but the concentrations were still below levels of likely concern, and we observed no corresponding increases in concentrations of polycyclic aromatic hydrocarbons (PAHs). The postfire increases in metal concentrations were not generally observed in the nonresidential soils, highlighting the importance of combustion of anthropogenic materials for potential soil contamination from wildfires at the WUI. While soil contamination from the 2021 Marshall Fire was lower than expected, and likely below the threshold of concern for human health, our study highlights some of the challenges that need to be considered when assessing soil contamination after such fires.

Spatial patterns and temporal trends of trace elements in mosses from 1990 to 2020 in Germany

BackgroundThe accumulation of trace elements in mosses is used as an indirect measure of atmospheric deposition and an important complement to the techniques used to monitor the Geneva Air Pollution Convention. The aim of this paper is to quantify and map temporal and spatial trends of metal enrichment in mosses collected in Germany in 1990, 1995, 2000, 2005, 2015 and 2020. Collection and chemical analysis of the moss samples were carried out according to international guidelines.ResultsThe analysis shows that since 1990, the median concentrations of As, Cd, Cu, Ni, Pb and Sb in the mosses have been decreasing significantly, with the with the highest decline of Pb (− 86%). This trend reversed in 2000 and 2005 and between 2015 and 2020 by increases in the concentrations of some trace elements. In the 2000 Moss Survey, higher concentrations were measured for Cd, Cu, Ni and Sb than in 2015, ranging from + 26% (Cu) to + 165% (Ni). For As and Pb, no significant changes can be observed in 2020 compared to 2015. The increase in metal concentrations in the mosses over the last five years does not correspond to the corresponding trends in reported metal emissions in Germany (2015–2020). In contrast, the long-term trends of the As, Cd, Cu, Ni and Pb concentrations measured in the mosses showed good overall correspondence with the emission trends in Germany (1990–2020). The long-term trends of the moss data are mostly weaker than those of the emission data. The spatial patterns of the temporal trends were mapped and discussed for As, Cd, Cu, Ni, Pb and Sb.ConclusionsThe study shows that for valid monitoring of atmospheric deposition, it is not enough to consider only emission data or the modelled deposition derived from these data. In this respect, the study provides one of many necessary contributions to the discussion on the extent to which analytes of current monitoring programmes are still relevant and up-to-date and whether there are new substances that are also relevant or even more relevant than existing analytes and to what extent this should be taken into account in designing future environmental monitoring.

Assessment of metals (Ni, Ba) deposition in plant types and their organs at Mersin City, Türkiye.

The increase in heavy metal concentrations in the air, especially after the Industrial Revolution, is notable for the scientific world because of the adverse effects that threaten environmental and human health. Among the trace elements, nickel (Ni) is carcinogenic, and all barium (Ba) compounds are toxic. Trace elements are critical for human and environmental health. Their threat further increases, especially in the urban areas and surroundings with a high population. In urban areas, the trace element contamination in the airborne can be reduced using plants. However, which plant and plant organs absorb trace elements could not be determined. In the present study, Ni and Ba concentrations in the branch, wood, and leaf samples of 14 species collected from the city center of Mersin province were determined. As a result, broad-leaved species' Ni and Ba concentrations in their leaf sample were generally higher than other species. Almost all species had the lowest Ni and Ba concentrations in their wood samples. Among these 14 species, it was found that Ni concentration was very high, especially in non-washed leaves of Platanus orientalis, Photinia serrulata, and Citrus reticulate, and Ba concentration was very high in Citrus reticulata, Chamaecyparis lawsoniana, Laurus nobilis, and Acer hyrcanum. Using broad-leaved species in urban areas where pollution is at high levels will significantly contribute to reducing Ni and Ba pollution. It is recommended that these points be considered in future urban landscaping projects.

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.

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.

Heavy metal transport with adsorption for instantaneous and exponential attenuation of concentration

Heavy metal pollutant is a serious problem in environmental pollution, and it is very difficult to eradicate once it enters the soil. As heavy metal adsorption has been proven to occur, the heavy metal’s behaviour can be modeled as a transport equation with adsorption. Previous adsorption term mostly due to the concentration alone, while in here, the desorption effect given by the rate of change of the concentration is also included. Also, the heavy metals are frequently considered to enter the soil after being dumped into the soil for a certain period of time. But, quick dumping onto the soil can introduce heavy metal instantaneously. Heavy metals entering the soil through leaching or when their concentration in the soil is influenced by chemical reactions, can all lead to the exponential decay of heavy metals entering the soil. Based on two-dimensional advection diffusion equation (ADE) with the new adsorption term, analytical solutions are obtained for the cases of instantaneous and exponential attenuation of heavy metals emission to soil by the method of Laplace transform. The results highlight the significant influence of emission type on the peak concentrations. If heavy metals are instantaneously enter the soil, the peak occurs in the range of 1–3 m radius from the point of emission on the first day, while for exponential attenuation the peak occurs close to the point of emission. Furthermore, there exists a correlation between retardation factors and heavy metal concentrations, where a decrease in retardation factors leads to an increase in heavy metal concentration. It is essential to investigate both types of heavy metals emission to provide valuable information for proper pollution management, effective environmental regulations and enforcement.

Germination and early seedling growth in four Plantago species in response to Zn, Cu and Fe

Abstract Heavy metal contamination is an increasingly pressing global ecological concern adversely affecting plant growth. Phytoremediation is an eco-friendly and low-cost approach to help solve this problem by using plants to remove metals. This study aimed to evaluate the phytoremediation potential of four Plantago species, exposing them to different concentrations (0, 150, 300, 600 and 900 ppm) of zinc, copper, and iron during germination and early seedling growth. These are generally the phases of the plant life cycle most sensitive to stress. The germination percentage (GP), mean germination time (MGT), radicle, hypocotyl and cotyledons length, biomass, water content and tolerance index (TI) were recorded under controlled conditions. The results indicated that metal-induced stress significantly reduced GP, increased MGT, and inhibited seedling growth with increased metal concentration. The relative toxicity of the tested metals could be ranked as Fe > Cu > Zn. Regarding the Plantago species, P. tunetana and P. lanceolata could be considered highly tolerant, P. albicans moderately tolerant, and P. afra low-tolerant to metal toxicity during germination. Therefore, P. tunetana and P. lanceolata present an excellent potential for phytoremediation of metal-contaminated zones.

Wildland-urban interface wildfire increases metal contributions to stormwater runoff in Paradise, California.

The 2018 Camp Fire was a large late-year (November) wildfire that produced an urban firestorm in the Town of Paradise, California, USA, and destroyed more than 18 000 structures. Runoff from burned wildland areas is known to contain ash, which can transport contaminants including metals into nearby watersheds. However, due to historically infrequent occurrences, the effect of wildland-urban interface (WUI) fires, such as the Camp Fire, on surface water quality has not been well-characterized. Therefore, this study investigated the effects of widespread urban burning on surface water quality in major watersheds of the Camp Fire area. Between November 2018 and May 2019, 140 surface water samples were collected, including baseflow and stormflow, from burned and unburned watersheds with varying extent of urban development. Samples were analyzed for total and filter-passing metals, dissolved organic carbon, major anions, and total suspended solids. Ash and debris from the Camp Fire contributed metals to downstream watersheds via runoff throughout the storm season. Increases in concentration up to 200-fold were found for metals Cr, Cu, Ni, Pb, and Zn in burned watersheds compared to pre-fire values. Total concentrations of Al, Cd, Cu, Pb, and Zn exceeded EPA aquatic habitat acute criteria by up to 16-fold for up to five months after the fire. To assess possible transport mechanisms and bioavailability, a subset of 18 samples was analyzed using four filters with nominal pore sizes ranging from 0.22 to 1.2 μm to determine the particulate size distribution of metals. Trace and major metals (Al, Ba, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) were found mostly associated with larger grain sizes (>0.45 μm), and some metals (Al, Cr, Fe, and Pb) also included a substantial colloidal phase (0.22 to 0.45 μm). This study suggests that fires in the wildland-urban interface increase metal concentrations, mainly through particulate driven transport. The metals with the largest increases are likely from anthropogenic disaster materials, though biomass ash also is a major contributor to water quality. The increase in metals following WUI burning may have adverse ecological impacts.

The Safety Assessment of Chemical Grouting “Sodium Silicate-based” in Indonesian Soils

Chemical grouting is a method to improve or accelerate the solidification process on a loose soil. The implementation of improper chemical grouting may lead to affect the safety level of groundwater; thus, the technical ability and safety should be analyzed comprehensively to prevent degenerative effect on environment. Volcanic soil is targeted on this research coherent to the abundancy in Indonesia. In this study, a field scale test was conducted to validate leaching test results that were obtained in the lab and to confirm the safety of sodium silicate-based chemical grouting. In addition, the geoelectric survey was conducted to ensure the flowing of groundwater by observing resistivity of soil layer. On laboratory test result, the significance basic pH was observed, in consequence some test revealed an increase in concentration of heavy metals. The bench test was conducted in Jatinangor area’s soil as a representative of Indonesian soil to validate the laboratory result. During the bench test, the pH of ground water was monitored continuously for 5 months, where a slight increase in the pH values of ground water was observed. In addition to that, water samples were collected and analyzed in the laboratory to examine heavy metal contamination in ground water on the 18th day after the chemical grouting injection was started. However, the increased concentration was not found which indicates the pH control shall be the main control of metal leaching. As the conclusion, pH monitoring as early measurement for chemical grouting effect on groundwater is proposed to be set as standard for chemical grouting work.