Low Concentrations Of Heavy Metals Research Articles

Application of selected indicators to assess contamination of municipal landfill leachate and its impact on groundwater

Leachate formation is one of the most important factors taken into account during the operation and long-term management of municipal waste landfills. Systematic assessment of groundwater and leachate contamination may be useful in selecting the appropriate method of leachate management or treatment processes. The use of indicators to quantify the contamination potential of leachate and groundwater in the vicinity of MSW could help landfill managers assess their quality. Therefore, the aim of the study was to assess the representativeness of selected indicator methods for analyzing the temporal variability of leachate and groundwater properties in the vicinity of two municipal waste landfills in a Central European country (Poland). The leachate pollution index (LPI), sub-LPI and adjusted leachate pollution index (r-LPI) were used to assess the quality of leachate water, while the landfill water pollution index (LWPI) was used to assess the variability of groundwater quality. The results confirmed that LWPI is an effective method for assessing the quality of groundwater in the vicinity of municipal waste landfills. The obtained results confirm the negative impact of landfills, despite the insulation used. LWPI showed poor quality of groundwater and visible impact of the landfill (landfill W, average LWPI - 2.34) and moderately polluted waters and minor impact of the landfill (landfill S, average LWPI - 1.37). In most cases, it was observed that two parameters, EC and TOC, are the main factors contributing to the deterioration of groundwater quality. The sub-LPI analysis showed that leachates from both landfills have a very low content of heavy metals, so they should not have a negative impact on the biological treatment process. The obtained r-LPI values were in all cases higher than the calculated LPI values. For landfill S, the average r-LPI was 26.3 (Z-1) and 25.7 (Z-2). However, the average LPI was 13.5 (Z-1) and 13.2 (Z-2). For landfill W, the average r-LPI was 14.6 and the average LPI was 11.4. Analysis conducted on multi-year leachate and groundwater data using specific indicators can help managers better understand the impact of MSW on surrounding areas and help avoid potential operational problems in the future.

Optimized Cultivation of Stropharia rugosoannulata Using Winter Jujube Wastes and Safety Risk Assessment of the Cultivated Mushrooms

Substantial agricultural waste, including winter jujube residues, pits, and sawdust, is generated during the planting and processing of winter jujubes. To recycle these wastes, they were used to cultivate Stropharia rugosoannulata. The nutrient composition, mineral elements, 179 pesticide residues, and heavy metals in the wastes and S. rugosoannulata were tested. Cultivating the liquid spawn of S. rugosoannulata with 40 g/L winter jujube residue as a substitute for glucose significantly increased the mycelial pellets’ biomass by 136%, resulting in more uniform pellets. Secondary strains of S. rugosoannulata were cultured using winter jujube pits, showing no significant difference in mycelial growth rate and vigor compared to the control (CK) across additive levels of 10%–30%. The fruit bodies of S. rugosoannulata cultivated with winter jujube sawdust exhibited no detectable pesticide residues and a lower heavy metal content than the allowable limits, with a protein content of 36.7 g/100 g. Additionally, the mineral element potassium surpassed sodium by over 200 times, rendering it a potassium-rich, low-sodium food source. Utilizing winter jujube wastes for S. rugosoannulata cultivation effectively repurposed these wastes through sustainable recycling. This approach not only reduces cultivation costs but also yields safe and nutritious edible fungal products.

Groundwater Contamination by Heavy Metals in Malaysia: Sources, Transport, and Remediation Strategies

Groundwater contamination by heavy metals is a pressing environmental concern, particularly in regions highly dependent on groundwater as a freshwater source. While Malaysia primarily relies on river water, certain states and islands depend on groundwater for their supply. Research on heavy metal contamination in Malaysia’s groundwater remains limited, making it crucial to study the distribution and mobility of contaminants to develop appropriate remediation strategies. In addition to natural sources, anthropogenic activities such as landfills, mining, and the use of fertilizers contribute significantly to heavy metal pollution in groundwater. Factors like rainfall, fluctuating groundwater levels, and low soil pH can exacerbate heavy metal leaching into aquifers. Various models and techniques, including 2D resistivity imaging and MODFLOW, are used to assess groundwater flow and contaminant transport. These models suggest that contaminant concentrations decrease with increased depth and radial distance from pollution sources such as landfills and mining areas. The health risks associated with heavy metal exposure through groundwater consumption are significant, necessitating effective remediation strategies. Phytoremediation is an economical solution for groundwater containing low concentrations of heavy metals, while permeable reactive barriers may be suitable for more complex cases, pending detailed site investigation. This review aims to examine the current state of knowledge on heavy metal contamination in Malaysia’s groundwater, focusing on sources, distribution patterns, and movement of pollutants. It also seeks to evaluate existing remediation methods, including phytoremediation and permeable reactive barriers, while identifying gaps in research, particularly concerning risk assessments and heavy metal speciation.

Arsenic and Heavy Metals in Soils and Plants near Sulfide Mines: Implications for Phytoremediation and Phytomanagement.

The accumulation of heavy metals (i.e., As, Cu, Ni, Pb, and Zn) in soils and native plant species near copper, nickel, and pyrite mines in Vietnam was assessed. The highest soil As, Cu, Ni, Pb, and Zn concentrations recorded in mine soils were 42.3, 1570, 9870, 128, and 462 mg/kg, and those in agricultural soils were 11.4, 453, 94.9, 34.4, and 147 mg/kg, respectively. Pollution index (PI) values indicated heavy pollution (PI = 3.99-13.0) for mine soils, and unpolluted to severely polluted (PI = 0.65-2.84) for agricultural soils. Soil enrichment factors had a wide range, from minimal to extreme enrichment of heavy metals (EF = 0.03-91.4). Arsenic minerals may be the main source of high As concentrations in sulfide mines. The As, Cu, Ni, Pb, and Zn concentrations of 20 native plant species near three mines were in the ranges of 0.05-1150, 3.17-123, 0.47-291, 0.08-6.34, and 6.87-168 mg/kg (dry weight, DW), respectively. Based on the recorded hyperaccumulation levels (1150 mg/kg, DW), bioaccumulation factors (BAF = 2.4-90.0), biomass, and rapid growth, Pteris vittata L. is considered a promising plant for phytoextraction of As in soils. Bidens pilosa L. has potential for phytostabilization of sulfide-bearing soils, given its low concentrations of heavy metals in plant shoots, BAF values of <1, high biomass, and wide distribution. Integrated phytoremediation and phytomanagement are applicable to metal-contaminated soils. Phytomining, energy crops, and vegetation cover should be investigated for the phytomanagement of metal-contaminated soils in mining areas.

Effectiveness of constructed wetland technology-treated industrial wastewater on the spinach (Spinacia oleracea) health risks and biochar efficiency.

In peri-urban areas, use of industrial wastewater for irrigation is a common practice. Industrial wastewater contains cadmium, chromium, lead, nickel, and other elements that deteriorate food quality and affect human health. Biochar has been proven to remediate heavy metal contaminated soil by reducing their mobility and bioavailability. A pot experiment was conducted to evaluate the efficiency of different levels of biochar on spinach growth with low heavy metal concentration and to minimize associated health issues. The experiment lasted two months and the treatments: Control (tap water), untreated and treated industrial wastewater and both in combination with biochar (0.5% and 1%) were applied in completely randomized design. Findings suggested that treated industrial wastewater with 1% biochar resulted in maximum plant height, shoot weight, chlorophyll contents (SPAD value), photosynthetic and transpiration rate. Biochar significantly reduced heavy metal mobility in soil due to its porous structure, high pH, higher CEC, and variety of surface functional groups. The cumulative hazard index (HI), hazard quotient, cancer risk, and total cancer risk (TCR) were calculated using method provided by US-EPA for each metal. All treatments had HI values of < 1, however applying 1% biochar significantly reduced the HI values to 2.00E-01 and 2.88E-01 in adults and children, respectively. TCR for all treatments was < 1, while treated industrial wastewater and biochar (1%) has significantly reduced to 1.55E-02 and 1.91E-03 for adults and children, respectively. Thus, it was determined that irrigation with industrial effluents caused toxicity in vegetables, which had a negative impact on human health. Biochar effectively mitigated metal toxicity in both soil and spinach plants that resulted in reduced health/cancer risk.

Assessment of selected tree species as phytoremediation agents in polluted soils

The study investigates the ability of selected tree species to absorb heavy metals (Pb, Ni, Zn) from polluted soils. Seedlings of Adansonia digitata (P1), Jatropha curcas (P2), and Hildegardia barteri (P3) were transplanted into polythene pots with soils from a dumpsite (T1), highway (T2), industrial area (T3), and farmland (T4), forming a 3x4 factorial experiment replicated five times in a Completely Randomized Block Design. Pre-sowing analysis showed T1 and T2 had the highest Pb and Zn concentrations, T3 had the highest Ni, and T4 had the lowest heavy metal concentrations. After 12 weeks, heavy metal concentrations decreased in all soils. P1 concentrated metals in the root, P2 in the shoot, and P3 in various plant parts, with significant differences between species. P2 was identified as an effective phytoextractor for Pb and Zn (TF > 1), and P3 for Ni. All species showed potential for phytostabilization. The study concludes that these species are viable options for phytoremediation of heavy metals in contaminated soils.

Soilless Production of Lettuce (Lactuca sativa) in the Atacama Desert Using Fog Water: Water Quality and Produce Mineral Composition

Soilless vegetable production in the Atacama Desert of Northern Chile is spreading since it is perceived as an alternative that requires much less water than open field soil production. However, strong competition between mining and urban use for human population consumption exists, forcing growers to use alternative water sources. Fog is commonly present in the coastal areas of Northern Chile; however, little information exists with regards to its chemical composition and the effect on nutrient quality of the produce. To address this knowledge gap, a set of experiments was carried out in Chañaral, a small town located in the Atacama Desert of Northern Chile. There, a 200 m2 greenhouse equipped with twenty deep flow pools was used in two consecutive growing cycles. Water for the mixing of the nutrient solution was collected from the fog using fog-catchers and later stored in 2000-L tanks. Fog water quality (electrical conductivity, pH and mineral content) was monitored directly from the storage tanks. Two types of lettuce, green butterhead and red oak leaf, were compared on their yield and accumulation of nutrients and heavy metals. The results indicate that fog water is of good quality for soilless production, with an electrical conductivity value of 0.65 ± 0.18 and low content of heavy metals. Plants’ heavy metal accumulation is below the recommendation of Food and Agriculture Organization and World Health Organization. Fog water presents as a viable water source for soilless production in Northern Chile.

Chemometric evaluation, source apportionment, and health risk analysis of natural spring water in Murree, outer Himalayas

IntroductionContamination of water is a critical threat to human health at a global level. Water pollutants, such as heavy metals, can have adverse effects on the well-being of humans, animals, and the natural ecosystem of a region. Study AreaMurree is the most visited tourist destination in Pakistan. The rural population of Murree uses natural spring water for drinking, household use, and irrigation. MethodsThis study assessed the elemental concentration of water from 20 natural springs in Murree using Inductively Coupled Plasma Optical Emission Spectroscopy. Source apportionment and spatial distribution of heavy metals were assessed using statistical approaches such as Pearson's correlation coefficient, principal component analysis, and interpolation. The study assessed the quality of water for drinking and irrigation in Murree's natural spring water using the metal index, sodium absorption ratio, magnesium absorption ratio, percentage sodium, Kelly's ratio, and salinity hazard. The health risks associated with heavy metals were assessed by computing Average daily dose, Hazard quotient, Hazard Index, and Cancer Risk. ResultsThe mean concentration of metals in mgL-1 varied in the following order: Ca (51.23) > Na (22.3) > Mg (16.26) > Si (6.51) > K (1.59) > Se (1.17) > Sr (0.48) > Ba (0.209) > Al (0.060) > Li (0.015) > Zn (0.005) > Fe (0.0033) > Ni (0.0032) > Cr (0.001). Metal index was calculated for Al (0.3), Ba (0.29), Cr (0.024), Ni (0.14), Fe (0.004), Zn (0.002), Sr (0.07), Mg (0.32), and Ca (0.25), revealing low levels of metal pollution. The geology of the study area was identified as the primary source of heavy metals in the water. The estimated values of health hazards showed that ingestion is the primary exposure pathway, with children having a higher risk. The health hazards posed by the heavy metal contact from the waters of Murree are not alarming. Quality indices show that the irrigation water sourced from the natural springs is of satisfactory quality. ConclusionThe study concluded that the spring water of Murree has low concentrations of heavy metals; their concentration is dependent upon the geology of the study area and is good for drinking and irrigation.

Enhanced removal of lead ions from wastewaters by electrochemical adsorption using nitrogen-doped Ti3C2Tx MXene

As a two-dimensional material containing transition metal carbides and nitrides, MXene is often used in capacitive deionization for its excellent hydrophilic and pseudocapacitive properties. Nitrogen doping is widely used to improve the adsorption properties of certain materials. However, the effect of nitrogen doping on the electrochemical adsorption properties of MXene remains unclear. In this work, nitrogen-doped Ti3C2Tx MXene was synthesized using a simple hydrothermal method to achieve highly selective and efficient removal of Pb(II) at a constant cell voltage. The concentration of Pb(II) decreased from 4.95 to 0.02 mg L−1 in a 100 mg L−1 NaCl supporting electrolyte after electrosorption. The removal efficiency of Pb(II) reached 99.5%, whereas it was only 15.2% for Na+. The introduction of nitrogen functional groups increased the electrical conductivity and layer spacing of MXene, thereby improving the pseudocapacitive adsorption performance in the presence of Pb(II). The complexation function of the Ti-OH group on nitrogen-doped Ti3C2Tx surface increased and contributed to the selective adsorption of Pb(II). The removal efficiency of Pb(II) increased with increasing solution pH and cell voltage, reaching the maximum value at pH 5.0 and 1.5 V, respectively. The effect of supporting electrolyte type on the removal of Pb(II) was negligible. In addition, the removal efficiency for mixed heavy metal ion solutions, including Cu(II), Ni(II), and Pb(II), exceeded 79.0%. It exhibited the highest removal efficiency for Pb(II) at 97.9%. After five cycles of electrochemical adsorption–desorption, the nitrogen-doped Ti3C2Tx maintained a stable Pb(II) removal efficiency of 97.0%. This work provides a promising material for the electrochemical removal of low-concentration heavy metal ions from wastewaters.

Spatial and seasonal dynamics of zooplankton functional groups and their relationship with environmental factors in urban rivers in Haikou City, China

The urban rivers, including Changwang, Meishe, and Wuyuan in Haikou City, China, are vital water resources. Despite the rivers experiencing anthropogenic impacts, limited studies have investigated their water quality and ecological community structure. This study assessed zooplankton functional groups' spatial and seasonal dynamics relative to environmental factors in the three urban rivers. The samples were collected and analyzed seasonally between March and December 2019. The environmental factors varied significantly at spatial and seasonal scales (p < 0.05). Meishe and Wuyuan Rivers had higher electrical conductivity, salinity, TN, and TP than Changwang, which had low turbidity. Seasonally, higher TP, TN, NH3-N, and CODMn levels were found in the spring, while summer and autumn experienced high temperatures. Additionally, spring and summer had high Chl-a levels. Likewise, spring had the lowest heavy metal concentrations, while nearly all metals were elevated in winter and summer. Generally, the average metal content followed the order of Mn > Zn > Cu > Ni > As > Cr > Co > Pb > Cd. The environmental parameters were within class III of the China standard for surface waters (GB 3838–2002), suggesting negligible pollution. This study identified 159 zooplankton species, including 62 Rotifers, 50 Protozoans, 31 Cladocerans, and 16 Copepods. They were classified into 11 functional groups, dominated by Rotifers filter feeders (RF), Rotifers carnivores (RC), and small copepods and cladocerans filter feeders (SCF), followed by Middle copepods and cladocera carnivores (MCC) and Middle copepods and cladocerans filter feeders (MCF). Analysis of similarity (ANOSIM) revealed seasonal differences (p < 0.001) in zooplankton functional groups, with RF and RC most dominant in summer, autumn, and winter, while SCF, MCF, and MCC were dominant in spring. Hence, the redundancy analysis (RDA) and Pearson Correlation analysis revealed that temperature, Chl-a, TP, salinity, CODMn, NH3-N, TN, As, Co, and Cd were the main environmental factors influencing zooplankton functional groups. This study helps understand urban rivers' water quality and ecological community structure, bridging the knowledge gap. The findings are essential for water quality monitoring and management.

Eco-friendly thiol-functionalized magnetic oxygenous carbon nitride nanocomposites for effective elimination of heavy metals

The increased pollution of water resources by toxic heavy metals poses a huge threat to the aqueous ecosystem. Since the low concentrations of heavy metals are often highly toxic but difficult to remove, novel efficient adsorbents still need to be explored. Herein, the superparamagnetic thiol-functionalized oxygenous carbon nitride nanocomposite (CNO/Fe3O4-SH) with multifunctional groups such as –NH2, –OH, –SH, and –COOH was fabricated by a simple and eco-friendly method. The maximum adsorption capacities of Pb2+, As3+, and Cd2+ ions on CNO/Fe3O4-SH at pH = 6 were 80.79, 71.78 and 66.19 mg/g, respectively, when their equilibrium concentrations were 20 mg/L. Under the equilibrium concentration below 0.01 mg/L, the adsorption capacities of these heavy metals over CNO/Fe3O4-SH were much higher than those of other adsorbents. The competitive adsorption investigations showed that the adsorption order in polymetallic solutions was Pb2+ > As3+ > Cd2+. Adsorption kinetics and isotherms studies indicated that the adsorption of Pb2+, As3+ and Cd2+ by CNO/Fe3O4-SH was attributed to monolayer adsorption and the adsorption process was controlled by chemical adsorption. The thermodynamic experiments showed that the adsorption processes were spontaneous and endothermic. After six adsorption/desorption cycles, CNO/Fe3O4-SH maintained its original morphology and adsorption ability, indicating its excellent regeneration performance, which had significant potential application in the decontamination of trace heavy metal ions in water.

Promoting microalgal biofilm formation by crushed oyster shell-hydroxyapatite layer on micropatterned aluminum coating for heavy metal ions removal

Microalgal biomass has shown inspiring potential for the heavy metal removal from wastewater, and forming microalgal biofilm is one of the sustainable methods for the microalgal biomass production. Here we report the formation of microalgal biofilm by accelerated colonization of typical algae Chlorella on thermal sprayed aluminum (Al) coatings with biologically modified surfaces. Micro-patterning surface treatment of the Al coatings promotes the attachment of Chlorella from 6.31 % to 17.51 %. Further enhanced algae attachment is achieved through liquid flame spraying a bioactive crushed oyster shell-hydroxyapatite (CaCO3-HA) composite top layer on the micropatterned coating, reaching 46.03–49.62 % of Chlorella attachment ratio after soaking in Chlorella suspension for 5 days. The rapidly formed microalgal biofilm shows an adsorption ratio of 95.43 % and 85.23 % for low concentration Zn2+ and Cu2+ in artificial seawater respectively within 3 days. Quick interaction has been realized between heavy metal ions and the negatively-charged extracellular polymeric substances (EPS) matrix existing in the biofilm. Fourier transform infrared spectroscopy (FTIR) results indicate that both carboxyl and phosphoryl groups of biofilms are crucial in the adsorption of Cu2+ and the adsorption of Zn2+ is due to the hydroxyl and phosphate groups. Meanwhile, the biofilm could act as a barrier to protect Chlorella against the attack of the heavy metal ions with relatively low concentrations in aqueous solution. The route of quick cultivating microalgal biofilm on marine structures through constructing biological layer on their surfaces would give insight into developing new techniques for removing low concentration heavy metal ions from water for environmental bioremediation.

Ecological risk assessment of heavy metals in surface sediments and their impact on macrobenthos in Asan Bay, South Korea

Bay ecosystems with unique economic and ecological value are more vulnerable to heavy metal pollution than other marine ecosystems. In South Korea, rapid economic development has exacerbated heavy metal pollution in bay environments. This study analyzed concentrations of seven heavy metals and the structure of macrobenthic community in Asan Bay. Five heavy metal indices (PLI, Pn, RI, TRI, and MERMQ) were used to assess ecological risk. Additionally, spearman correlation, biota–environment matching (BIO-ENV), and redundancy analysis (RDA) were utilized to determine the influence of heavy metals on macrobenthic communities. Although average concentrations of seven heavy metals were below sediment quality guidelines (SQGs), the average concentration of Cd was close to the threshold effects level (TEL). The nemerow pollution index (Pn) and the potential ecological risk index (RI) indicated that Cd was the primary heavy metal contributing to ecological risk. Spearman correlation, BIO-ENV, and RDA indicated that heavy metals were the main environmental factors influencing macrobenthic communities in Asan Bay. However, five heavy metal indices (PLI, Pn, RI, TRI, and MERMQ) did not show a response to the macrobenthic communities. Overall, low concentrations of heavy metals have a certain negative impact on macrobenthic communities in Asan Bay. This study can serve as an important reference for marine environmental protection and policy-making in Asan Bay.

Life cycle assessment of rice residue as the lightweight biocomposites for structural ceiling: A critical review

The research focuses on the sustainable utilization of rice residue for lightweight biocomposites, emphasizing the importance of pre-treatment methods like NaOH interventions on cellulose, hemicellulose, and lignin in rice residue. The balance in pre-treatment timing is crucial for maintaining the structural integrity of these components. Rice Husk Ash (RHA) stands out for its low heavy metal content and high refractoriness, making it versatile for various applications. Rice straw (RS), another component of rice residue, offers abundant cellulose and low lignin, making it suitable for biocomposite matrices. The study delves into extracting cellulose and CNCs from RS for eco-friendly packaging, targeted drug delivery, and high-quality composites. It also explores how advanced farming practices can reduce waste and enhance crop yields.

Engineering properties as a supplement cementitious material of ground copper reduction slag extracted valuable metal from Cu slag

We have examined whether the copper reduction slag (CRS) generated after recovering valuable metals from copper slag (CS) by reduction process can be used as supplementary cementitious materials (SCMs). According to the test results, the Cu secondary slag with low Fe, Cu, and heavy metal contents had a suitable oxide composition for using as a SCM. CRS showed better grinding efficiency than that of ground blast furnace slag (GGBS). Ground CRS contributed to the formation of tobermorite under autoclaved curing conditions. The compressive strength of CRS mortar replacing 50 % of OPC generated 93 % of that of the OPC mortar. Based on the results of this study, we found that the CRS has highly appropriate engineering characteristics for using as SCMs for concrete. In addition, it is judged that the method of using secondary slag as a material for precast concrete produced under hydrothermal conditions can greatly contribute to the construction process of buildings by securing mechanical performance.

Comparison of Phosphogypsum-Steel Slag-Based cement and Portland cement for stabilization of heavy metals in oil-based drillings cuttings

This research compared Portland cement and Phosphogypsum-Steel Slag-Based (PSSB) cement in terms of their capabilities to stabilize heavy metals (specifically lead and nickel) in Oil-Based Drill Cuttings (OBDC). In the experimental section, the qualitative analysis of heavy metal constituents in OBDC was captured by X-ray Photoelectron Spectroscopy (XPS). Additionally, an acetic acid leaching test was implemented for the heavy metal leaching concentration to evaluate the ceramsite stabilization effect on OBDC. In the simulation phase, cement models, heavy metal ion models, and stabilization models were constructed to explore the stabilization mechanism of heavy metals. Results demonstrated that PSSB cement exhibits superior stabilization effects on OBDC compared to Portland cement. Flame Atomic Absorption Spectrophotometry (FAAS) tests showed that PSSB cement reduced Ni and Pb leaching by 21.87 % and 47.32 %, respectively, compared to Portland cement. In PSSB cement, the diffusion coefficients for Ni and Pb ions were observed to decrease by 42.92 % and 79.63 %, respectively, as revealed through Mean Square Displacement (MSD) analysis. The cohesive energy of PSSB cement was 76.73 % lower than that of Portland cement, and its interaction energies for stabilizing Ni and Pb ions were 59.43 % and 76.22 % lower, respectively, demonstrating greater stability and efficiency in metal stabilization. PSSB cement exhibited lower heavy metal concentration and better structural stability than Portland cement.

Analysis of 18 elements in Alpine goat milk in the first third of lactation

The research objective was to examine the influence of the first third of the lactation stage on 18 mineral elements in Alpine goat milk. The research was carried out on 20 goats of the French-Alpine breed, which were on average 5 years old and in the fourth lactation. The goats were monitored on the 30th and the 90th day of lactation. Their milk was analysed for chemical composition by the infrared spectroscopy. By means of inductively coupled plasma (ICP), a total of 18 minerals were analysed (Ca, P, K, Na, K, Mg, Fe, Zn, Cu, Se, Mn, Mo, Co, Cr, Ni, Cd, Pb, As and Hg). The period of milk sampling in the first third of lactation significantly influenced the changes in concentrations of Na, Se, Mo, Cr, Ni and As. Significantly higher concentrations of Na and As were determined in milk sampled on the 90th day, while lower concentrations of Se, Mo, Cr and Ni were determined in milk sampled on the 30th day of the first third of lactation. Analysis of the correlation coefficients between the investigated trace elements and the selected toxic elements in Alpine goat milk showed a significantly positive correlation between Ca:Mg, Ca:P, Ca:Co, Ca:Ni, Ca:Mo; Mg:P, Fe:As, Pb:Cd and P:Ni. In the first third of lactation, Alpine goat milk contained a very low concentration of heavy metals. The described changes indicate that Alpine goat milk is rich in essential elements, while the concentration of toxic elements is very low in the first third of lactation.

115 years of sediment deposition in a reservoir in Central Europe: Effects of the industrial history and environmental protection on heavy metals and microplastic

AbstractHumans have considerably influenced accumulation rates and sediment composition in lake deposits. Due to near‐continuous accumulation, lakes and reservoirs are an excellent archive of these anthropogenic influences. The Urft Reservoir in the Eifel Mountains, western Germany, provides a unique record of the human influence on the landscape for the past 115 years. In 2020 and 2021, 24 cores and 23 surface samples were obtained from the bottom of the, by that time drained, reservoir. Grain size, heavy metals, weathering signatures and microplastic were analysed. For the chronology, caesium‐137 and microplastic were used. Using the first occurrence of microplastic as well as different plastic types for dating was not successful. However, a distinct layer with a high number of microplastic particles could be traced back to a fire in 1991 and was used as an additional stratigraphic marker in the age‐depth model. A period of relatively high accumulation rates in the reservoir occurred in the mid‐1950s and was related to enhanced construction works in the local valleys. Analysis of heavy metal content in the reservoir sediments shows a strong connection to historical changes in ore industry in the valley of the Urft. Stricter environmental protection laws and the decline of the metal processing industry resulted in a reduced input of lead, copper and zinc in the reservoir until the mid‐1980s. Since then, heavy metal content has remained relatively constant. A major flooding event in July 2021 did not lead to the remobilisation of older contaminated deposits as indicated by low heavy metal content in flood deposits. Accordingly, also the microplastic content is not increasing following the extreme event. Due to the degree of weathering of the flood deposits, it is argued that mainly hillslope material was transported into the Urft and subsequently into the Urft Reservoir during this event.

Soil–water contamination assessment due to dumpsite-impacted leachates in a metamorphic environment

Environmental contamination is a complex issue that significantly impacts human health and ecological systems, especially in developing countries like Nigeria. This study explores the interplay between surface-subsurface soil-rock resistivity and subsurface geotechnical properties, along with multiple soil-water pollution indices at and around the Old Owo-Ikare road (OOIR) dumpsite in southwestern Nigeria. Water samples from five wells and one stream were collected and analyzed, alongside twelve soil samples from four trial pits at varied depths for geoenvironmental assessment. Analyzed hydrogeochemical parameters include Na, Ca, Mg, K, Cr, Pb, Zn, Ni, Mn, Fe, and cations (NO, SO4, Cl) in the water samples. Nine dipole-dipole electrical resistivity tomography (ERT) profiles and six Schlumberger vertical electrical sounding (VES) points were used to determine surface–subsurface resistivity distribution. Water analysis results showed elevated levels of K, Ni, Cr, and Pb concentrations. Geotechnical tests indicated that most dumpsite soil meets good landfill material criteria with low permeability (5.92×10−6 to 1.49×10−4cm/s). ERT and VES inverted models revealed four lithologic layers with two main curve types (HA and QA). Elevated heavy metal levels in the dumpsite soil and inverted resistivity models suggested leachate contamination in the topsoil and weathered bedrock units. Despite relatively lower heavy metal concentrations compared to other Nigerian and Ghanaian dumpsites, multi-pollution indices indicated significant contamination in both water and soil samples, posing moderate to very high environmental risks based on World Health Organisation standards. Additionally, human health risk assessment suggested a risk of cancer and non-cancer-related diseases from prolonged well water consumption. Therefore, ongoing monitoring and remediation efforts are essential to forestall imminent pollution in uncovered areas.

Molybdenum tailings calcination for phase composition of Si-Ca-K-Mg fertilizers: Modification of phase transformation and its effects on plant growth

The high value and comprehensive utilization of molybdenum tailings for the production of fertilizer of calcium silicon magnesium potassium (Si-Ca-K-Mg fertilizer) was investigated, considering the abundant potassium feldspar (K-feldspar) content in the tailings. The effects of calcination temperatures, times, and additives (CaCO3 and CaSO4) on reaction degree, final product type, and phase transition process were studied. The results indicated that at 1200 °C, calcination time of 120 min and m(molybdenum tailings):m(CaCO3):m(CaSO4) = 1:0.7:0.2, the final product met Type I product requirements according to Chinese national standards GB/T36207-2018 as well as extremely low heavy metal contents. In the calcination process, CaO resulted from CaCO3 absorbs the liquid phase produced during K-feldspar decomposition to form CaSiO3, facilitating the K-feldspar decomposes into KAlSiO4. Simultaneously, the Ca2+ in CaSO4 replaces undecomposed K-feldspar’s K+. Additionally, CaO reacts with Al2O3, MgO, and SiO2 to produce gehlenite (Ca2Al2SiO7) and akermanite (Ca2MgSi2O7), providing plants with Ca, Mg, and Si elements. The nutrients of the fertilizer were readily assimilated by plants, improving acidic soil without causing any harm to the soil or vegetation. This work offers new ideas for large-scale and high-value utilization of molybdenum tailings as well as addressing the shortage of soluble potassium resource in China.