Total Pb Concentrations Research Articles

Use of sequential extraction methods to evaluate the environmental impact of trace metal in the Iraqi coastlines

The geochemical distribution of several trace metals (lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), nickel (Ni), chrome (Cr), cobalt (Co) and iron (Fe)) was investigated using five sequential extraction procedures to provide information on their distribution and environmental impacts on the Iraqi coastal sediments. Sediment samples were collected from 16 sites along the coast to determine the concentrations of the above metals. The concentration and ratios of these metals were estimated in the sediment extract (concentration on the exchange surfaces, carbonates, manganese oxides and iron oxides, organic matter and those associated with the remainder) using extraction methods (magnesium chloride, 1 molar of sodium acetate, 0.5 molar of hydroxylamine hydrochloride, 0.2 molar of ammonium oxalate, concentrated nitric acid and 25% of hydrofluoric acid) to extract and separate the above fractions in order. The results indicated that the total sediment content of Pb and Cd were higher than their rate of occurrence in the crust, while copper, zinc, nickel, chrome, cobalt and iron were within those limits. According to the I-geo the metals Cr, Cu and Zn are considered at unpolluted class while Ni and Pb were ranged from moderately to strongly level. On the other had Cd was found at extremely level as its I-geo exceeded the highest-class value. These metals are bonded to different power bonds. Pb, Cr and Co have dominant in exchangeable and carbonates fraction. Iraqi tidal flats is characterized by very high risk considering Cr, Pb, Co and Cu which represented by RAC values, so they can move to the solution to become available for living.

Source apportionment and source-specific risk assessment of bioavailable metals in river sediments of an anthropogenically influenced watershed in China

Integrated source analysis and risk assessment of metals facilitate the development of targeted risk management strategies. However, previous studies usually addressed total concentration rather than bioavailability, and consequently overestimated metal risk, especially natural source-related risk. In this study, a source-specific risk assessment was conducted by integrating the source analysis of bioavailable metals in surface sediments. Moreover, risk assessment was performed using two bioavailability-based indices: the total availability risk index (TARI) and a modified index of mean probable effect concentration quotients (mPEC-Q). A representative river watershed in eastern China was selected as the study area. Findings revealed that the total concentrations of Pb, Cu, Zn, Cr, and Ni in the sediments were 1.4–2.2 times higher than the local soil background values. Using a modified community bureau of reference (BCR) sequential extraction procedure, the dominant fraction for Pb, Cu, Zn, and Cr in the studied area was found to be the residual fraction, constituting 53.63–62.44% of the total concentrations. This suggested that a significant portion of the metals potentially originated from natural sources. Nevertheless, the concentration enrichment ratio (CER) indicated that anthropogenic sources contributed significantly, accounting for 67.84–87.68% of bioavailable metals. The positive matrix factorization (PMF) model further identified three different sources of bioavailable metals, with a descending concentration contribution sequence of industrial sources (37.61%), mixed traffic and natural sources (33.17%), and agricultural sources (29.22%). Both the TARI and mPEC-Q index values indicated that the bioavailable metals generally posed a moderate risk, and Ni was the priority pollutant. Industrial sources contributed the most to the total risk, although the contribution from TARI-based assessment (37.27%) was lower than that from the mPEC-Q assessment (46.43%). This study provides an example of the consideration of metal bioavailability in the context of source-specific risk assessments to develop more reasonable management strategies.

Assessment of depth wise distribution, enrichment, contamination, ecological risk and sources of soil heavy metals over an Industrial area in Southern India

Assessing the depth-wise distribution of heavy metals in soil can provide valuable insights into the extent of enrichment, contamination, and the possible sources of pollutants. A study was conducted in parts of Patancheru Industrial areas of Hyderabad, India to assess the vertical distribution of heavy metal content in soil, focusing on enrichment, contamination, and pollutant sources. Sixty soil samples from 15 sites, spanning four depths (0–15 cm, 15–30 cm, 30–50 cm, 50–100 cm) were analyzed for total Fe, Mn, Zn, Cu, Pb, Cr, Co and Ni concentrations. The concentrations of Fe, Mn, Zn, Cu, Pb, Cr, Co, and Ni, regardless of the study depths and sites, range from 2570–10,667, 22.5–439, 11.6–47.2, 3.47–14.2, 5.53–31.7, 36.0–63.1, 2.99–17.5 to 10.5–47.3 mg kg−1respectively. The mean concentrations of all the measured heavy metals showed minor variation across depths, except for Zn and Pb. Moreover, the mean concentration of all the measured heavy metals at various soil depths was within the threshold or target limits except for total Ni. At certain sampling depths and locations, Ni content exceeded the permissible threshold of 35 mg kg−1 in the soil. Surface soils (0–15 cm) exhibited moderate to significant enrichment of Pb, Zn, Cr, and Co. The enrichment factor for the overall Pb concentration varies from 3.02 to 24.73, indicating a range of moderate to very high enrichment throughout the soil depths. Following Pb, Cr exhibits enrichment levels ranging from 2.31 to 9.35, while Co ranges from 1.07 to 5.58.The sites within the study area varied in contamination levels, spanning from moderate contamination to a slight degree of pollution, as assessed by the contamination/pollution index of each element. Principle component analysis and enrichment factor values show that Cu originated primarily from natural sources; while Pb and Cr were likely to be anthropogenic to purely anthropogenic and Zn, Mn, Ni, and Co had both crustal and like to be anthropogenic origins. The maximum and minimum ecological risk index (ERI) values were recorded for Pb and Zn content, respectively. The maximum PERI value of 15.8 was recorded in the study area, indicating a low ecological risk level. However regular monitoring of the heavy metal concentration in soils is recommended over the study area to maintain a low level of ecological risk via reclamation interventions.

A feasible method of induced biological soil crust propagation through the inoculation of moss and addition of soil amendments in a Pb-Zn tailing pond

The stacking of tailings results in serious environmental pollution and plant growth difficulty. However, moss and microorganisms can successfully colonize in tailings to form biological soil crusts (BSCs) and provide a feasible means to ecologically restore tailing reservoirs. Nonetheless, information on this approach is scarce. In this study, a 90 day field experiment was conducted to form BSCs in a Pb-Zn tailing pond in Jianshui County, China by inoculating in-situ moss crust fragments and adding three soil amendments. Results showed that induced BSCs successfully propagated, and the biomass increased to 15.51–20.33 times the initial value. Moss inoculation considerably increased the soil moisture, water-holding capacity, and phosphatase by 9.2 %, 8.8 %, and 64.0 %, respectively, and decreased exchangeable fraction Pb by 30.7 %. The co-inoculation of moss and biochar remarkably increased soil moisture, water-holding capacity, cation exchange capacity, sucrase, urease, and phosphatase activity by 22.3 %, 23.4 %, 116 %, 80.5 %, 28.6 %, and 240 %, respectively, and decreased the bulk density by 13.3 %. The addition of red soil reduced the total contents of Pb and Zn, whereas that of the stabilizer increased the pH and decreased the bioavailability of Pb and Zn. Co-inoculation greatly increased the biotic community species richness and changed their structure and function. The dominant photosynthetic eukaryotes shifted from Synechococcales to Oscillatoriales. Bacterial nutritional types shifted from chemoautotrophy to photoautotrophy and chemoautotrophy, and fungal nutritional types changed from oligotrophy to copiotrophy. These changes drove alterations in bacterial and fungal community structures. These results indicated that the propagation of induced BSCs can rapidly improve the soil structure and nutrient cycle, restore the biotic abundance and function, and facilitate the soil formation of tailings. Thus, this method holds promise for the ecological restoration of tailings.

Risk-spreading strategies of two dwarf bamboos in heterogeneous Pb (lead) environments

As a typical clonal plant, dwarf bamboo has potential applications in the remediation of Pb (lead) -contaminated soils; however, the environmental risk-spreading strategies of dwarf bamboo in heterogeneous Pb-contaminated environments are not known. To this end, we conducted hydroponic experiments on two species of groundcover bamboo, Sasa fortunei (Van Houtte) Fiori (SF) and Sasa auricoma (Mitford) E.G. Camus (SU), with seven treatments including two environments, homogeneous and heterogeneous. The results showed that SF protected the distal ramets (DRs) and that SU did the opposite in a homogeneous Pb environment. In the heterogeneous Pb environment, the NTR of both bamboos (RSISF = 0.64/0.44, RSISU = 0.40/0.33) was higher than that under the heterogeneous high-concentration environment (RSISF = 0.15/0.28, RSISU = 0.26/0.26). Moreover, the total Pb concentration of SF was as high as 80123.5 mg/kg and that of SU was as high as 53333.33 mg/kg, and in general, SF was more capable of absorbing Pb. In the heterogeneous low-Pb environment, the ascorbic acid and proline levels of the TRs (Pb-treated ramets) were elevated to alleviate oxidative stress; in contrast, antioxidant enzyme activities of SU were all reduced due to the damage caused by Pb absorption. The results of the experiments showed that SF had a greater risk-spreading capacity and higher Pb concentrations than SU in heterogeneous environments, and therefore, SF had better Pb bioenrichment and tolerance than SU. We proposed a novel metric (RSI) to assess the ability of plants to spread risk, and the results of the study provid a basis for dwarf bamboo phytoremediation in heterogeneous Pb environments.

Spatial-temporal Variations and Pollution Assessment of Heavy Metals in Sediments of Qionghai Lake in Xichang City

Based on the analysis of the total concentrations of 10 metals in the sediment core and total concentrations and chemical fractions of seven metals in the surface sediments of Qionghai Lake in Xichang City, Sichuan Province, the spatial-temporal characteristics of metal accumulation and pollution over the past century and the potential ecological risk of metals in surface sediments were studied. Before the 1970s, metal concentrations in the sediment core were stable. The total concentrations of Al, Fe, K, and Cr in the sediment core exhibited visible peaks in the 1970s, which were related to the enhanced input of fine-grained topsoil caused by increasing precipitation, lake reclamation, and deforestation. Since the 1990s, the total concentrations of Al, Fe, K, and Cr decreased with the reduced topsoil erosion, whereas the total concentrations of As, Cd, Cu, Pb, and Zn gradually increased or remained stable. The enrichment factor results showed that Cd, Pb, and Zn were the main contaminants, with Cd as the typical contaminant in the sediment core. The Cd contamination started in the 1960s and has remained at a moderate level since the 1990s. In the surface sediments, the total concentrations of Cd were higher in the northwest lake area, and no visible spatial concentration trends of the other metals were displayed. The bioavailable fractions of Cd, Pb, and Zn accounted for 95%, 63%, and 48% of the total metal concentrations on average. Among the bioavailable fractions, Cd was mainly in the acid-soluble fraction, and Pb and Zn were mainly in the reducible and oxidized fractions. The bioavailable fractions of the other metals were less than 27%. The results of total concentrations and bioavailable fractions of metals revealed that Pb and Zn in the surface sediments were slightly or moderately contaminated, and Cd was moderately contaminated on average. Cd contamination was at a severe level in the northwest lake area. The concentrations of anthropogenic Cd, Pb, and Zn in the surface sediments estimated from the total and bioavailable concentrations were comparable (P>0.05), indicating that anthropogenic metals primarily existed in bioavailable fractions in the sediment. Integrating the assessment results from sediment quality guidelines, potential ecological risk index, and chemical forms of metals, Cd in surface sediments may pose a high ecological risk, whereas the other metals has a low ecological risk.

Faucet-mounted point-of-use drinking water filters to improve water quality in households served by private wells

Approximately 13 % of Americans rely on private wells for household potable water. As private wells are not regulated beyond initial construction and often employ limited or no treatment, source water from wells can be vulnerable to contamination. While several studies have assessed applications of point-of-use (POU) filters in improving municipal tap water quality, few have investigated their use with private well water. This effort aims to build on previous examinations of POU treatment as a strategy to reduce adverse household drinking water exposures by: 1) assessing the effectiveness of commercially available faucet-mounted POU filters for improving microbial and chemical water quality in homes with private wells; and 2) documenting household ease of use and satisfaction with the filters. Faucet-mounted POU filters were distributed to 21 homes reliant on private wells in southern West Virginia and southwestern Virginia. Study participants were asked to collect water samples from two taps in their homes pre-filter installation, and again two-weeks and four-weeks post-installation. Participants filled out surveys about perceptions of their drinking water and the filter. Concentrations of Total Coliform, Ba, Cd, Cr, U, Cu, Pb, Al, Fe, Mn, Zn, and Sr were significantly lower (p < 0.05, Wilcoxon Rank Sum) in filtered water samples compared to paired unfiltered samples (n = 42) for the study period. However, concentrations of certain contaminants in filtered samples from homes with high levels of source water contamination still exceeded drinking water standards. Less than half of study participants reported that they intended to keep using the filters, citing issues of flowrate. Our findings suggest that faucet-mounted POU filters, while effective in reducing contaminants, might not be an appropriate intervention to improve water quality for all homes on private well water. Future investigation is required to improve filter user satisfaction and better assess appropriate source water chemistries for implementation.

Heavy Metals in Sediments of Subarctic Meromictic Lakes of the White Sea as Possible Tracers of Environmental Changes

Meromictic lakes of the marine coast, quite widely distributed in the northern hemisphere, are the result of climate changes and glacier retreat. The bottom sediments of these lakes serve as a geological chronicle of the history of marine basin’s development with the geochemical occurrence forms of elements indicate various processes of their accumulation. This paper presents research results concerning the occurrence of forms of heavy metals in lake sediments along the coast of the White Sea. These results are based on a sequential seven step leaching procedure, followed by ICP-MS analysis and subsequent statistical data processing. To determine differences among the examined geochemical parameters, Pearson’s correlation analysis and Ward’s cluster analysis were utilized. The total content of Cr, Mn, Fe, Co, Ni, Zn, V, and Pb in the sediments did not exhibit significant differences based on their degree of isolation from the sea. The major contribution to deposition of these metals in sediments of the meromictic lakes studied is the residual form, encompassing the mineral matrix of the sediment. At the same time, the elevation of mobile forms for all the metals examined corresponds to an increase in the isolation of lakes from the White Sea. In the meromictic lake sediments, concentrations of Cu, Mo, and U demonstrated significant increases in forms tightly bound to organic matter, while Cd exhibited an association with Fe-Mn oxyhydroxides. Notably, a significant difference in the occurrence forms of Cu, Cd, Mo, and U was evident in the reduced sediments of meromictic lakes when compared to those of open sea bays. The meromictic lakes along the White Sea coast, positioned at various stages of isolation, hold promise for investigating the migration of metals in response to environmental changes.

Rice Water—More a Source of Nutrition Elements or Toxic Arsenic? Multi-Element Analysis of Home-Made (Natural) Rice Water and Commercialized Rice-Based Products Using (HG)-ICP OES

Although rice is a well-known source of nutrients, it unfortunately accumulates As the most compared to other cereal plants. Due to the growing interest in rice-based cosmetics, the aim of the work was the multi-element analysis of various home-made (natural) rice waters and commercialized ready-to-use rice-based cosmetics for skin/hair. The total concentrations of Al, As Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in raw rice and rice products were determined using inductively coupled optical emission spectrometry (ICP OES) after wet sample decomposition in the presence of concentrated HNO3. In the case of As, the hydride generation (HG) technique was used as a sample introduction system to the ICP OES instrument. Five different procedures, including washing/rinsing, soaking, boiling, and fermentation steps, and three rice types, i.e., white, brow, and jasmine, were used for this purpose. The effects of the water temperature, the contact time of rice grains with water, and the type of rice on the water-soluble concentrations of elements were examined and compared. A significant difference in the solubility of elements was observed depending on the type of rice, with the lowest percentage of extraction noted for brown rice. The best option was soaking unwashed rice grains in a six-fold excess of cold water for 30 min. The selection criterion was to preserve the highest content of essential elements (Ca (0.76–1.2 mg kg−1), Cu (9.2–43 ng k−1), Fe (0.096–0.30 mg kg−1), Mg (6.9–11 mg kg−1), Mn (0.16–10.32 mg kg−1), and Zn (0.083–0.25 mg kg−1)) with reduced to a minimum As level, i.e., &lt;5 ng g−1 (2.8–4.8 ng g−1), making this water safe for consumption. In contrast, regularly drinking water after boiling or soaking rice grains in hot water carries the risk of consuming an excessive amount of this element due to As content exceeding the permissible value, i.e., 10 ppb. Finally, these home-made products were compared with commercialized cosmetics for skin/hair, with satisfactory results.

The potential to produce safe textiles in a phytoattenuation strategy: The fate of Cd and Pb during industrial treatments on contaminated hemp fibers

Industrial hemp (Cannabis sativa L.) is getting increased attention as a sustainable alternative to synthetic fibers and cotton in the textile industry, as well as a candidate for phytoremediation, as it has been shown to tolerate stress from heavy metal-contaminated soil and experiences no or only little decrease in yields. With the EU Soil Strategy of 2030 promoting land reuse, hemp could be a perfect candidate for fiber production for textiles while growing on heavy metal contaminated land and restoring the soil. This strategy, combining safe biomass production and land valorization, is called phytoattenuation. In this study, Cd and Pb-contaminated hemp fibers underwent demineralization and bleaching treatments, commonly used in the textile industry. Total and extractable Cd and Pb concentrations were analyzed and assessed against legal safety thresholds and toxicity thresholds used in the textile industry to evaluate the safety of these fibers for textile production. Total and extractable Cd and Pb concentrations were below the total (40 mg/kg Cd and 90 mg/kg Pb) and extractable (0.1 mg/kg Cd and 1.0 mg/kg Pb) safety limits in the treated fibers after the combined demineralization and bleaching treatments. To understand in which parts of the fiber Cd and Pb are concentrated, fibers were analyzed for their cellulose, hemicellulose, and lignin content after each treatment. Extractives such as pectin were removed during demineralization and bleaching removed part of the lignin and hemicellulose. This corresponded respectively to a decrease in Cd and Pb, suggesting that Cd is rather bound to pectin in the primary wall, while Pb could be bounded to lignin and hemicellulose in the secondary wall of the fiber. However, the fate of the elements in the fiber remains complex. Overall, the results are promising for safe textile production from hemp fibers grown on Cd and Pb-contaminated soil.

Does eating fish cause cancer? A case study metal(loid)s accumulation in mackerel and sardine tissues from İskenderun Bay, Türkiye.

Due to the increasing harmful effects of metal(loid)s over time, it has become important in environmental studies carried out to increase environmental awareness. It is important to investigate the cumulative presence of metal(loid)s in nature, their interactions with each other and risks posed by fish consumption for human health. Total concentrations of As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn were determined in muscle and gill tissues of horse mackerel (Trachurus trachurus) and sardine (Sardina pilchardus). Metal analyses were carried out using Inductively Coupled Plasma-Mass Spectroscopic (ICP-MS) methods. In both tissues, Fe and Zn concentrations were the highest and Cd, Cu and Pb concentrations were the lowest. The target hazard coefficient, estimated daily intake, target cancer risk, total target hazard coefficient, and hazard indices were calculated to assess the risks to an individual's health from consuming fish. Hazard index and total target hazard coefficient values calculated for each fish exceeded 1 but were very close to 1. Target cancer risk values of As and Ni were found to be 10-6 and 10-4 for Pb. These limit values indicate the need for regular monitoring of the region. In addition, the interactions between the metal(loid)s accumulated in the tissues were analyzed and a high correlation was found between As-Ni, which poses a risk to public health.

A coupled geostatistical and machine learning approach to address spatial prediction of trace metals and pollution indices in sediments of the abandoned gold mining site of Bekao, Adamawa, Cameroon

Trace metals present in high amounts in aquatic systems are a perpetual concern. This study applied geostatistical and machine learning models namely Ordinary Kriging (OK), Ordinary Cokriging (OCK) and Artificial Neural Network (ANN) to assess the spatial variability of trace metals and pollution indices in surface sediments along the Lom River in an abandoned gold mining site at Bekao (Adamawa Cameroon). For this purpose, thirty-one (31) surface sediment samples are collected in order to determine the total concentrations of As, Cr, Cu, Fe, Mn, Ni, Pb, Sn and Zn. These trace metals are used to compute pollution indices as the sediment pollution index (SPI), the Nemerow index (NI), the modified contamination degree (mCD), and the potential ecological risk assessment (RI). OK, OCK and ANN models are compared to determine the best model performance. The best models are selected based on the values of the root mean square error (RMSE), the coefficient of determination (R2), the scatter index (SI) and the BIAS. Results showed that the sequence of trace metal mean concentrations in the sediments is Fe > Mn > Cu > Ni > Sn > Cr > Zn > Pb > As. The mean concentrations of Ni, Cu, Zn and Sn are above the average shale values (ASV) and the pollution status is globally moderate to significant with a low potential ecological risk. The spatial dependency obtained with semivariogram models are moderate to weak for Mn, Fe, Ni, Pb, SPI, NI, mCD, RI As, Cr, and Sn and strong for Cu and Zn. According to cross-validation parameters, ANN model is the best method for the prediction on trace metal concentrations and pollution indices in surface sediments along the Lom River in the abandoned gold mining site of Bekao.

Accumulation of Trace Metals in Fruits from Mango and Syzygium guineense Growing in Residential Households from a Contaminated District of Lubumbashi (DR Congo): Is Fruit Consumption at Risk?

Copper smelting has been a source of soil contamination with trace metals in Penga Penga (Lubumbashi). The residents are exposed to trace metal ingestion, and planting trees is challenging in such soil conditions. Nevertheless, planting trees in former household dumps or using various types of amendments has allowed the provisioning of fruits in a few residences. From the perspective of scaling up the process, a survey has been conducted with the aim of assessing the effectiveness of the planting processes on the trace metal content in fruits and leaves of Mangifera indica L. and Syzygium guineense (Willd) DC. Samples were collected from residential households in Penga Penga and Kalebuka (a non-polluted suburb). The bioconcentration factor (BCF) and the safe weekly consumption (SWC) were calculated for each species. The results showed higher values of total and soluble concentrations of Cu, Pb, and Zn in the rhizosphere of the two species in Penga Penga. Metal concentrations were higher in the fruits and leaves from Penga Penga, with 47% of samples above the FAO and WHO thresholds (vs. 18.5% in Kalebuka). The BCF values were below 1, demonstrating the effectiveness of the process in reducing the translocation of metals to leaves and fruits. Recommendations from the SWC limit Pb consumption to 9 kg for mango flesh and Cd consumption to 6.6 kg for S. guineense fruits in Penga Penga (vs. 78 kg and 68 kg in Kalebuka). Finally, the results of this study provide interesting lessons for the scaling up and technical itinerary of planting trees in Penga Penga.

Chinese sapindaceous tree species (Sapindus mukorosii) exhibits lead tolerance and long-term phytoremediation potential for moderately contaminated soils

Heavy metal pollution in metropolitan soils poses significant risks to human health and the entire ecosystem. Effective mitigation strategies and technologies are crucial for addressing these environmental issues. Fast-growing trees are an essential part of phytoremediation projects all over the world and provide long-term ecological benefits to mankind. This study assessed the lead tolerance and phytoremediation potential of a fast-growing soapberry tree species (Sapindus mukorossi) in moderately contaminated soil. Two independent experiments were conducted to assess its tolerance at (i) germination level and (ii) prolonged growth stage. In the germination experiments, seeds were exposed to lead (II) nitrate Pb (NO₃)₂ at various concentrations (0, 5, 10, 20, 50, 100, 200, 300, 400 and 500 μM) for 120 days. Results showed significant differences in germination time, germination index, seedling vigor index, energy of germination, final germination, germination inhibition, seedling height and root/shoot weight compared to the control experiments. In the prolonged growth experiments, seedlings were grown for six months in soils amended/spiked with different Pb concentrations (T0 = 0, T1 = 20, T2 = 50, T3 = 100, T4 = 150 and T5 = 200 mg kg−1 soil) and their biomass was determined. The highest biomass achieved in six months (T0: 12.62 g plant−1), followed by (T1: 12.33 g plant−1), (T2: 12.42 g plant−1), (T3: 11.86 g plant−1), (T4: 10.86 g plant−1) and (T5: 10.06 g plant−1) respectively. S. mukorossi showed no visible signs of Pb toxicity over a six-month period. During six months of exposure, the total Pb content in S. mucrossi tissues were classified as roots > leaves > stems. The highest cumulative absorption of Pb occurred between the fourth and fifth months of exposure. Maximum transfer factor (TF) was detected during the fourth month ranging from 0.888 to 1.012 for the different Pb concentrations. Furthermore, the growth behavior, lead accumulation, bioconcentration factors (BCF) and tolerance index (TI) indicated that S. mucrossi may tolerate moderate Pb concentrations for longer periods. These findings suggest that S. mukorossi may be deployed for long-term phytoremediation coupled with urban forest applications in the future.

Environmental effects of potentially toxic elements and the magnetic susceptibility distribution in the surface bottom sediments in the Vistula estuary (Gulf of Gdańsk, Poland)

PurposeThis study is aimed at analyzing the spatial distribution of magnetic susceptibility and the content of potentially toxic elements (PTEs) in the surface layer of bottom sediments in the Vistula estuary (Gulf of Gdańsk, Poland) in relation to local sedimentary conditions. We also assessed the usefulness of magnetic susceptibility measurements to identify changes in sediment properties caused by anthropogenic factors.Materials and methodsBottom sediments were collected along three transects using the Van Veen grab sampler. The following properties were determined: granulometric composition, organic matter and carbonate content, pH, electrical conductivity, and heavy metal content (Cd, Cr, Cu, Fe, Ni, Pb, and Zn). Specific (mass) magnetic susceptibility (χ) was measured using the MS2 Bartington® laboratory magnetic susceptibility meter. To characterize the conditions of the sedimentary environment in the study area, statistical analysis was performed on selected parameters of grain size distribution, such as mean grain diameter (Mz) and sorting (σ1) indices.Results and discussionThe research showed significant differences in the sedimentary environment (erosion vs. deposition processes) along the studied transects which were controlled by the wave regime, sea currents, and river water inflow. Open-water sediments were richer in organic matter and more saline than deltaic sediments, which in turn were characterized by higher pH and higher carbonate content. The highest mean total content of Pb, Cu, Ni, and Zn and the highest magnetic susceptibility (χ) were determined in open-water sediments, while the highest Fe and Cr values were obtained for deltaic sediments. Statistically significant differences between these sediments were found only for organic matter (LoI), Pb, Cu, and Cd content. Magnetic susceptibility showed a moderate correlation with Pb, Cu, Cd, and Zn (rs 0.4–0.6).ConclusionPTE content and magnetic susceptibility of sediments showed a very high heterogeneity within the study area, depending mainly on the location (delta vs. open waters), grain size composition, and organic matter content. Our results demonstrated that magnetic susceptibility analysis is an easy method that can be used to complement the identification of technogenic changes in the marine environment.

Microbial metabolic activity in metal(loid)s contaminated sites impacted by different non-ferrous metal activities

Many non-ferrous metal mining and smelting activities have caused severe metal(loid) contamination in the local soil environment. The metabolic activity of soil microorganisms in four areas affected by different metallurgical activities (production vs. waste disposal) was characterized using a contamination gradient from the contaminated site to the surrounding soils. Results indicated that the soil microcalorimetric and enzyme activities were correlated with the fractionated metal(loid) properties (p < 0.05). All four areas had high total As, Cd, Pb, Sb, and Zn concentrations, of which mobile As, Cu, Ni, Pb, Sb, and Zn were higher in the contaminated sites than the surrounding sites, reflecting an elevated environmental risk. Three contaminated site areas had lower microbial activities than their surrounding sites suggesting that high metal(loid) concentrations inhibited soil microbial communities. Interestingly, the fourth area (tailing pond) showed an opposite trend (i.e., increased microbial activity in contaminated vs. surrounding areas). The microbial thermodynamic parameters of this contaminated site were higher than its surrounding sites, suggesting that the selected microbial communities can develop a functional resistance to metal(loid)s stress. This study provides a theoretical basis for ecological prevention and control of metal-polluted areas.

Contamination of As, Cd, Cr, Hg and Pb in soils in Arica commune (Chile).

The objectives of this study are (a) to determine the background concentration of As, Cd, Cr, Hg and Pb in Arica commune; (b) to determine the degree of soil contamination in Arica city using environmental indices and (c) to evaluate the human health risk of these potentially toxic elements. In the rural area of Arica commune, 169 samples were taken and 283 samples were taken in the urban area of Arica city. Total concentrations of Cd, Pb and Cr were determined by EPA 3052 and EPA 6010 C. Mercury was determined by EPA 7473. Arsenic was determined by EPA 7061A. The available concentrations of As and Cr were determined by dilute hydrochloric acid and EPA 6010C. Environmental indices were applied for pollution and US EPA model was used to evaluate human health risk. Background concentrations were As 18.2, Cd 1.12, Cr 73.2, Hg 0.02 and Pb 11.8mgkg-1, respectively. Environmental indices show that soil samples are located between slightly contaminated to extremely contaminated. Human health risk analysis shows that children have higher levels of risk than adults. The analysis with available concentrations of As and Cr shows no carcinogenic risk for adults and children, but 81% and 98% of the samples were between 10-6 and 10-4, that means intermediate risk.

An analysis of heavy metal contamination in vegetables and herbs growing in water hyacinth manure, case of Lake Chivero

The primary goal of this study was to determine concentrations of heavy metals in water hyacinth compost manure (Pb, Cd, Cu, Cr, and N) and their bioavailability in Brassica oleracea var acephala and mentha organs. Analysis also focused on the physiological responses of Brassica oleracea var acephala and mentha to water hyacinth compost.The target was to find if water hyacinth have high nutritive to enhance plant growth and act a an alternative solution for controlling water hyacinth if harvested from eutrophic Lake Chivero. Rhizofiltration ability of water hyacinth makes it potential source of fertilizer to plants since it accumulates all excess nutrients from hyper-eutrophic water sources. Before planting Mentha herb and Brassica oleracea var acephala, soil samples and compost were taken to the laboratory. The experiment was carried out in uncontaminated soil. For eight weeks, mature plants were harvested and their roots, stems and leaves were collected and plant materials were tested for heavy metal concentration to determine total metal concentration. The Bio-concentration Factor was used to calculate the concentration of heavy metals in Brassica oleracea var acephala and Mentha. The heavy metal accumulation rate in Brassica oleracea var acephala was calculated using a translocation factor. Heavy metal concentrations of Pb, Cd, Cu, Cr, and Ni were measured in compost treatments as well as Covo vegetables and mint herbs. Metal concentrations were greater than 1 mg/kg for Pb, Ni, Cu, and Cr, but not for Cd, which was below detection levels. The metals Pb, Ni, Cu, and Cr all had a BCF >1 mg/kg in Brassica oleracea var acephala and Mentha exceeded the WHO food safety guidelines. During the exposure experiments, the concentrations of Pb, Cd, Cu, Cr, and Ni in brassica oleracea var acephala vegetables and Mentha herbs increased. In decreasing order, Brassica oleracea var acephala and Mentha roots and leaves had the highest accumulation and total heavy metal concentration of Pb > Ni > Cu > Cd > Cr. In summary, water hyacinth from Lake Chivero cannot be used as a biofertilizer for food crops hence more research is required on other non-food crops and other uses like bio-fuel.

Spatial Distribution of Lead in the Soil of Urban Areas Under Different Land-Use Types

Awareness of lead (Pb) distribution and zoning in urban, agricultural, and industrial areas is of particular importance in environmental protection planning. This cross-sectional study aimed to determine the distribution of Pb in different uses with different levels of industrial development and human activities in urban areas in Hamadan during 2018. For this purpose, 146 soil samples were collected from 0-20 cm depth and prepared for air-dried laboratory analyses. Then, pH, electrical conductivity (EC), total Pb, and adsorbable Pb in the soil were measured. The results demonstrated that the mean concentration of total Pb is 88 mg/kg. In addition, the mean concentration of Pb in urban, industrial, and agricultural areas was 41 mg/kg, 30 mg/kg, and 17 mg/kg, respectively. Further, the average concentration of adsorbable Pb with a standard deviation of 0.3 in industrial, urban, and agricultural areas was 0.38 mg/kg, 0.16 mg/kg, and 0.06 mg/kg. Land use was an important source of Pb change in the studied soils; however, Pb change did not depend only on land use. Factors such as weather conditions or proximity to roads, as well as previous land uses, could affect the role of existing land use and be effective in the distribution of soil Pb. Studies revealed that the amount of the soil’s adsorbable Pb is more important than that of total Pb in different uses, which should be considered in any soil-related research.

The legacy of metallurgical atmospheric contamination in a mountainous catchment: A delayed response of Pb contamination

Metal-rich fumes emitted during ore smelting contribute to widespread anthropogenic contamination. Environmental archives (such as lake sediments) record fallouts deposited on lake and terrestrial surfaces during ancient mining and smelting activities. However, very few is known about the potential buffering effect of soils upon which metal falls out, prior to be released through runoff and or/erosion, hence leading to pervasive contamination fluxes long after the ceasing of metallurgical activities. Here we aim at assessing this long-term remobilisation in a mountainous catchment area. Lake sediments and soils were collected 7 km upward a 200-year-old historic mine. The PbAg mine of Peisey-Nancroix was operated between the 17th and the 19th centuries with a documented smelting period of 80 years. In lake sediments, the total Pb content varies from 29 mg.kg−1 prior smelting to 148 mg.kg−1 during ore smelting. Pb isotopes in lake sediments and soils provide evidence of anthropogenic Pb from the local ore (206Pb/207Pb = 1.173; 208Pb/206Pb = 2.094) during and after smelting, suggesting anthropogenic Pb remobilisation for 200 years. The accumulation rates of anthropogenic Pb calculated in lake sediments after the smelting period confirm such a remobilisation. Despite a decrease in this accumulation rate through time, soils still contain significant stocks of anthropogenic Pb (54–89 % of PbANTH). The distribution of present-day anthropogenic Pb in the catchment area depends mainly on topographic characteristics. Coupling lake sediments and soils investigations is thus necessary to constrain the long-term persistence and remobilisation of a diffuse contamination related to mining activities.