Bioavailability Of Cu Research Articles

New Insights into Health Risk Assessments for Inhalational Exposure to Metal(loid)s: The Application of Aqueous Chemistry Modelling in Understanding Bioaccessibility from Airborne Particulate Matter

Aqueous modelling of chemical speciation in simulated lung fluid (SLF) enables a better understanding of the underlying chemical factors that influence metal(loid) inhalation bioaccessibility from airborne particulate matter. Such an approach can be used to supplement experimental techniques that are integral to the health risk assessment of metal(loid) exposure by inhalational routes. In this paper, we modelled the aqueous chemistry of airborne particulate-bound metal(loid)s (As, Cu, Mn, Pb and Zn) in a SLF based on Gamble’s solution (neutral pH). The modelling was performed using two software packages (Geochemist’s Workbench 14 and OLI Studio 9.5) and a total of five thermochemical databases (GWB Thermo, MINTEQ, PHREEQC, WATEQ4F and the default database for OLI Studio). Modelled results were compared with experimentally determined bioaccessibilities for the NIST 2710a standard reference material (SRM) and with literature-reported bioaccessibilities for NIST 1648a and BCR 038 SRMs. Whilst the models correctly describe the observed increase in bioaccessibility for more dilute solid/liquid extraction ratios, the performance of the models against the fractional bias of the mean (FBmean) and the normalised mean square error (NMSE) statistical metrics was generally outside the acceptance criteria. Findings from an analysis of the main aqueous chemical species predicted to be present in SLF indicate that carbonate and chloride complexes of Cu, Mn, Pb and Zn predominate, whilst free cations (for Cu, Mn and Zn) and hydroxides (for Cu) also play a role in solubilisation. Arsenic is not predicted to form significant complexes with the SLF components and is present in solution mainly as the HAsO42− ion and its conjugate acid, H2AsO4−. For modelled runs where glycine and citrate were present, significant increases in the bioavailability of Cu and Zn were predicted as a result of complexation with these ligands. An additional finding from our experimental bioaccessibility results for NIST 2710a was that the inclusion of the lung fluid surfactant dipalmitoylphosphatidylcholine (DPPC) in the SLF did not significantly affect the bioaccessibility. Our study provides useful insights into the likely aqueous- and solid-phase speciation of metal(loid)s in SLF and highlights that future developments in this area should consider the role of mineralogy and surface interactions.

Wide-range detection of Cu-binding organic ligands in seawater using reverse titration

The toxicity and bioavailability of Cu in seawater were estimated using its chemical speciation. In this study, the concentrations and conditional stability constants (K'CuL) of Cu complexes with Cu-binding organic ligands (L) in seawater were determined using the reverse titration–competitive ligand exchange–adsorptive cathodic stripping voltammetry method. The concentrations of strong and weak ligands (L1 and L2, respectively) were determined using reverse titration via the addition of Cu to seawater samples to achieve ligand saturation. Our results revealed that the reverse titration method can be successfully used for the detection of high concentrations of L2. Using the reverse titration method, we detected L2 concentrations that exceeded 80 and 120 nM in seawater samples from the subtropical western North Pacific Ocean and Otsuchi Bay Japan, respectively. The K′CuL1 and K′CuL2 values obtained using the reverse titration method were comparable with those obtained using the forward titration method. Therefore, the reverse titration method can be used to determine the chemical speciation of Cu in the ocean and coastal regions as supplement to the more conventional forward titration method.

Metal distribution, bioavailability and isotope variations in polluted soils from Lower Swansea Valley, UK.

Soils in the Lower Swansea Valley, (UnitedKingdom) contain elevated level of metals, enough to cause direct or indirect effects on human health. This study assesses the severity of soil pollution and bioavailability of Cu and other metals (Ni,Zn, Co, Pb andCr) in soils with various distances from aNi refinery. We compare Cu concentrations in operationally defined soil fractions (bioavailable, bound to Fe/Mn oxide and incorporated in organic matter) with other metals (Ni, Zn, Pb, Co, Cr) usually occurring in ores used in metallurgic processes and report their pollution and geoaccumulation indices (PI and Igeo). Further, we use Cu stable isotope ratios (δ65Cu) to trace the fate and mobility of Cu in soils. Our data suggest a point source of contamination for some of the heavy metals including Ni (Igeo = 1.9), Zn (Igeo = 0.28) and Cu (Igeo = 3.6) near the Ni refinery. However, Co (Igeo = 0.15) and Pb (Igeo = 3.3) contaminations are likely to be linked to different sources. No elevated Cr levels (Igeo= -0.07) occur in any of the studied soils. All soil metals are predominantly associated with organic matter (>50%) which reduces their bioavailibility and thus their risk for ecological and human health.The Cu isotope data show that Cu in soil organic matter is enriched in 65Cu, while the lighter isotopes (63Cu) remain in the dissolved bioavailable Cu fraction (Δ65Cuorganic-bioavailable is +0.12 ± 0.13‰). This suggests the preferential complexation of 65Cu with soil organic matter after dissolution of Cu deposited to the soil. Thus, Cu isotope data can effectively indicate pathways of metal migration in polluted soils.

The Effect of Composting on the Multiple Heavy Metals in the River Sediment Investigated by Multivariate Analysis

This study investigated the passivation of multiple heavy metals (Cd, Cr, Cu, Zn, and Pb) in river sediments by composting with rice straw. The correlation between the selected environmental factors and the distribution of heavy metal fractions was assessed by multivariate analysis. The results suggested that the composting could reduce the bioavailability of Cu, Cd, Cr, and Pb. The influences of composting on the passivation of these five heavy metals are different. The greatest passivation of heavy metals is for Cd, which its bioavailability decreased 17.72%. The bioavailability of Cu, Pb, and Cr also partly decreased. However, there was almost no effect on the bioavailability of Zn. The results of multivariate analysis revealed that the predominant parameters affecting the variation of the bioavailability of different heavy metals were different in a complex composting system with multiple heavy metal pollution. While the variation partitioning analysis indicated that water-soluble carbon (WSC) was the statistically main factor affecting the bioavailability of Cd, Cr, Cu, Zn, and Pb. It provides a theoretical reference for optimizing the co-composting process in remediation of different heavy metal contamination in sediments.

Higher bioavailability of Cu and Zn in the eastern part of Johore Causeway: Will the pattern remain the same beyond 2030?

The purpose of this paper is to discuss Cu and Zn concentrations in Perna viridis soft tissues from the western and eastern parts of Johore Singapore Causeway. The polluted eastern portion of the Causeway had greater levels of Cu and Zn in different areas of the soft tissues of mussels than the western part. This indicated the eastern section of the semi-enclosed Causeway had higher Cu and Zn bioavailability than the western part. With some reports of high metal levels in the eastern part of the Causeway from 2015 to 2018, it is predicted that there will be a plausible constant source of anthropogenic metal contamination in the eastern part of the Causeway beyond 2030 if anthropogenic activities are not effectively controlled.

Bioavailability and Solubility of Heavy Metals and Trace Elements during Composting of Cow Manure and Tree Litter

Objectives. To characterize the total content of heavy metals (Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) and trace elements (As and Se) of interest, their bioavailability and solubility during the composting of cow manure and tree litter in piles inoculated with beneficial microorganism (IBM), or not inoculated (NBM), on the university campus of the Universidad Nacional Agraria La Molina (UNALM). Methods. The investigation evaluated composting in six piles, three IBM piles and three NBM piles, for 120 days. Every 30 days, a composite sample was taken from each pile. The raw materials used were cattle manure and tree litter. The variables analyzed were the total concentrations (content) of metals and trace elements of interest, extracted with diethylenetriaminepentaacetic acid/pentatetic acid (DTPA) (for the bioavailability study) and extracted with deionized water (for the solubility study). Results. The average values (n = 3) of the total content (mg·kg−1) on day 120 in IBM were in the following order: Zn (404.33) > Cu (86.33) > Pb (71.2) > Cr (34.33) > As (28.0) > Ni (13.83) > Mo (2.86) > Se (1.38) > Cd (1.32) > Hg (0.39) and in NBM: Zn (466.0) > Cu (112.23) > Pb (73.23) > Cr (35.33) > As (29.67) > Ni (14.37) > Mo (3.23) > Se (1.55) > Cd (1.38) > Hg (0.38). The values complied with the Austrian Compost Standard for Landscaping and Land Rehabilitation and the Peruvian Standard for Nonorganic Agriculture. Significant differences were observed in some elements ( p < 0.05) between 0 and 120 days in both types of pile (IBM and NBM). Conclusions. For nonorganic agriculture in Peru, urban compost is recommended, whereby raw organic materials are inoculated with beneficial microorganisms during the composting process to reduce the bioavailability of Cu and Zn, as these elements showed less bioavailability than noninoculated piles. The composting process for both piles (IBM and NBM) reduced the solubility in Cu, Pb, and Zn.

Dry-wet and freeze-thaw aging activate endogenous copper and cadmium in biochar

Abstract While biochar is useful for environmental remediation, the effects of aging on the activation of endogenous trace metals in biochar remain unclear. In this study, three biochars with different concentrations of copper (Cu) and cadmium (Cd) were produced from the straws of Pennisetum sinese grown in moderately-polluted (MB), highly-polluted (HB), and clean (CB) soils. The effects of aging on biochar properties and bioavailability of endogenous Cu and Cd were investigated by Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, Boehm titration, and chemical extraction before and after dry-wet (DW) and freeze-thaw (FT) aging. DW and FT aging increased the specific surface areas and abundance of oxygen-containing functional groups in the biochars. Aging decreased the biochar pH, degree of graphitization, and stability. The leachability of Cu and Cd were higher after FT aging than after DW aging, and the bioavailability of Cu and Cd were higher in MB and HB than those in CB. Aging increased the bioavailability of Cu in all biochars, whereas it only increased the bioavailability of Cd in MB. Aging increased the mobility of Cu and Cd by 2.31–12.2 and 0.22–1.31 times. The trends of the mobility and leachability of Cu were not consistent with those of total Cu in the biochars, while mobility and leachability of Cd and total Cd had the same trends. The activation of endogenous Cu was primary associated with the compositions of organic functional groups in the biochars. However, Cd activation was mostly related to the changes in the inorganic components and pH of the biochars. This study implies that aging can activate endogenous metals in biochars, and the potential environmental risk of a biochar should be carefully evaluated to ensure its safe and sustainable application.

Immobilization of Pb and Cu by organic and inorganic amendments in contaminated soil

Soil contamination with heavy metals has become a global environmental-health concern. A series of greenhouse experiments were conducted to investigate the effects of rice straw, rice straw derived biochar (BC), multi-walled carbon nanotubes, and single superphosphate (SSP) on immobilization of Pb and Cu via sequential extraction of BCR, total characteristics leaching procedure (TCLP), and metals phytoavailability to rapeseed in Pb and Cu spiked soil. Moreover, the residual effect of applied soil amendments on growth and uptake of Pb and Cu in tomato was also investigated in the metals spiked soil. In results, the addition of BC to Pb and Cu spiked soil proved the most effective amendment in modifying the distribution pattern of Pb and Cu from acid-soluble (less bioavailable) to residual fraction (non-toxic), thereby improving the geochemical stability of contaminated soil. The application of BC (6% w/w) reduced the uptake of Pb and Cu in shoot and root by 46 and 36%, and 77 and 58%, respectively. While investigating the residual impact in tomato, the uptake was decreased by 36 and 66% for Pb and 29 and 61% for Cu in shoot and root samples, respectively. With the application of BC (6% w/w), the concentrations of Pb and Cu in the shoot portion of tomato were below the permissible limits as set by the world health organization. The application of SSP was more effective in reducing TCLP-Pb to 0.2 mg L−1 in metals spiked soil compared to the other amendments. However, the bioavailability of Cu was increased with increasing SSP addition. In conclusion, the application of BC was more effective in reducing Pb and Cu phytoavailability through immobilization in contaminated soil compared to the other organic and inorganic amendments.

Heavy metals and community structure of microorganism changes during livestock manure composting with inoculation of effective microorganisms

Effective microorganisms (EM) is usually used in composting to improve the composting process. However, the effect of EM on heavy metals evolution was still unclear. This study was performed to illustrate the microbial community changes that occur during composting with the addition of EM and to determine the evolution of heavy metal speciation during this process. The requirement of harmlessness for pig manure was met after the addition of EM at a dosage of 0.5%, with a germination index of 96.42%. The bacterial and fungal diversity were both found to decrease during the composting process. Additionally, the bioavailability of Cu and Pb decreased significantly during composting. Significant correlations were observed between the microbial composition and the percentage of different heavy metals fractions; however, the mechanism responsible for this correlation requires further investigation. This study has the potential to contribute to control of heavy metal contamination during the process of recycling pig manure through the controlled addition of EM. Keywords: effective microorganisms, heavy metal, microbial communities, pig manure; composting DOI: 10.25165/j.ijabe.20201306.5674 Citation: Zhou H B, Shen Y J, Li R, Meng H B, Zhang X, Wang J, et al. Heavy metals and community structure of microorganism changes during livestock manure composting with inoculation of effective microorganisms. Int J Agric & Biol Eng, 2020; 13(6): 125–132.

Effects of Different Proportions of Pig Manures and Sugarcane Leaves on Cu and Zn Forms in Dry Fermentation

To explore the influence of different proportions of pig manures and sugarcane leaves on Cu and Zn in pig manures, pig manures and sugarcane leaves were used as raw materials to determine the changes of Cu and Zn effectiveness in pig manures under different proportions of pig manures and sugarcane leaves. The results show that under different proportions of pig manures and sugarcane leaves, (1)when the proportion of sugarcane leaves and pig manures was 2:1, it was adverse against the bio-availability of Cu. When the proportion was 1:2, bio-availability form (EX and RED) of Cu decreased significantly. (2) The bio-effective form content is ranked as below in Zn: C (1:2) >B (2:1). When the proportion of sugarcane leaves and pig manures was 1:2, bio-availability form (EX and RED) of Zn was the minimum, only 22.72%, and the passivation effect was good.

Effects of Hot-Melt Extruded Nano-Copper as an Alternative for the Pharmacological Dose of Copper Sulfate in Weanling Pigs.

This study was conducted to investigate the effects of hot-melt extrusion (HME)-processed copper (Cu) sulfate supplementation on the growth performance, gut microbiota, metabolic function of Cu, and bioavailability of Cu in weanling pigs fed a corn-soybean meal basal diets. A total of 180 piglets (Yorkshire × Landrace × Duroc) of mixed-sex randomly were allotted to six treatments on the basis of initial average body weight (6.36 ± 0.39kg) to six dietary treatments. There were six replicates in each treatment with 5 pigs per replicates. The dietary treatments included levels of CuSO4 (IN6, 6mg Cu/kg diets; IN125, 125mg Cu/kg diets), nano-CuSO4 (HME6, 6mg Cu/kg diets; HME65, 65mg Cu/kg diets; and HME125, 125mg Cu/kg diets), and Cu-methionine (ORG125, 125mg Cu/kg diets). The weanling pigs fed diets supplemented with the HME65 and HME125 showed a greater body weight and feed intake compared with IN6 and IN125 (P < 0.05). The weaning pigs fed diets supplemented with the HME125 showed the highest digestibility of gross energy in phase 1 and phase 2 (P < 0.05). The supplementation of HME125 significantly reduced theEscherichia coli (E.coli) in cecum and colon (P < 0.05). The supplementation of HME65 showed statistically equivalent effect on reduction of E. coli in the cecum and colon compared with IN125 and ORG125 treatments. The villus height in duodenum and jejunum of piglets in HME65 and HME125 treatments were higher than ORG125, HME6, IN6, and IN125 (P < 0.05). The gene expression of Atox1 was upregulated in IN125, HME125, and ORG125 treatments (P < 0.05). The expression of Sod1 was increased in IN125 treatment compared with IN6 treatment (P < 0.05). The HME125 treatment had the highest gene expression of ghrelin (P < 0.05). The Cu concentration of serum and liver was higher in the HME125 treatment than the HME6, IN6, and IN125 treatments (P < 0.05). The HME125 and ORG125 treatments showed a lower fecal Cu compared with IN125 treatment (P < 0.05). Taken together, these results suggest that the HME65 can be an alternative to IN125 in weanling pigs due to the greater overall average daily gain, improved villus height, and higher bioavailability.

Influence of Species Differences, Relative Metals Concentrations and pH on Uptake of Metals in Water by Fish

This study was designed to assess the effect of relative metals concentrations, pH and species variations on the uptake of copper (Cu), iron (Fe), calcium (Ca) and magnesium (Mg) in water, fish and fish parts to monitor the toxicity potentials of consuming these fish. The water and fish samples were obtained from four locations (Farin gada stream, Lamingo Dam, Nasco pond and mining pond) in Jos Metropolis, Plateau State, Nigeria, Water and six fish species samples were collected from the four locations, digested and analysed using Buck Scientific Atomic Absorption Spectrophotometer, model 210VGP. Results show that pH of the water sources from Farin gada stream, Lamingo Dam, Nasco pond and mining pond were 7.1, 6.5, 7.0 and 7.2 respectively. The concentrations of Cu in the water sources were 0.030±0.001, 0.010±0.003, 0.020±0.000, 0.027±0.000 in Farin Gada stream, Nasco pond, Lamingo Dam and mining pond respectively; Fe were 2.2±0.1, 0.0±0,000, 0.2±0.003 and 0.3±0.001; Ca were 305±3.0, 37±1.5, 110±3.5 and 163±4.5; Mg were 160±3.6, 126±4.8, 79±1.9 and 95±2.8 in that order above. Different fish species from the same water source bioaccumulated Cu, Fe, Ca and Mg at varying concentrations depending on source, fish species or the physicochemical properties. Different fish species have different preferences as to which part (body, gills and head) of the fish these metals are concentrated more. Lamingo Dam had five fish species, mining pond had three, while Nasco pond and Farin Gada stream had one each. The results established that uptake and bioavailability of Cu, Fe, Ca and Mg by fish in water depend on species variation, relative concentration of the metals in the source of water and the pH of the water.

Granular activated carbon-supported titanium dioxide nanoparticles as an amendment for amending copper-contaminated sediments: Effect on the pH in sediments and enzymatic activities

The problem of heavy metal pollution in sediments attracts increasing attention with the process of industrialization. In this study, a novel sediments amendment granular activated carbon (GAC)-supported titanium dioxide nanoparticles (GATN) was synthesized to amend copper (Cu)-contaminated sediments. The effect of the amendments on the potential mobility and bioavailability of Cu was evaluated by the concentration of Cu in the overlying water and the chemical speciations of Cu in sediments. After 35 days of incubation, GATN and GAC were separated from the GATN-amended sediments and the GAC-amended sediments. The European Community Bureau of Reference (BCR) sequence extraction procedure was performed on the separated sediments. Compared with the control group, the addition of 20% GATN amended sediments for 35 days, the Cu concentration in the overlying water decreased by 90.75%. Compared with original sediments, the exchangeable fraction and reducible fraction of Cu decreased from 42.30% to 17.36%–3.63% and 6.57%, respectively, and the oxidizable fraction and residual fraction of Cu increased from 13.57% to 26.77%–33.21% and 56.58%, respectively. The potential mobility and bioavailability of Cu were significantly reduced. According to the BCR sequence extraction results of the remaining sediments after the separation of the GATN, the Cu adsorbed on the GATN surface is mainly an oxidizable fraction, which is generated by the complexation reaction of hydroxyl (-OH) and Cu2+. Meanwhile, the present of GATN also can enhance the remediation capacity of sediments, which plays an important role during the amendment process. The pH was measured after GATN-amended sediments adding. Results showed that GATN improved their remediation capacity of sediments by optimizing the pH in sediments. The enzyme activity-experiment indicated that GATN effectively reduces the biological toxicity of Cu in Cu-contaminated sediments. Results verified that GATN, as a sediments amendment, has good application potential.

Bacterial consortium for improved maize production under oily sludge

AbstractOily sludge contains a wide range of carcinogenic and toxic organic and inorganic compounds that enter into the terrestrial environment and may be toxic to plants. Plants grown over oily sludge–contaminated soil may undergo changes in physiology and in the antioxidant enzymes system due to the presence of toxic hydrocarbons. Information is scarce regarding the inoculation of oily sludge on the changes in the physiology of plants. The present study evaluated the effect of a constructed bacterial consortium and fertilizers on maize (Zea mays L.) growth and survival and on its antioxidant system under the stress environment of 30% and 60% oily sludge. Maize grown over 30% and 60% oily sludge was inoculated with a consortium of plant growth–promoting rhizobacteria strains (Bacillus cereus [Acc KF859972], Bacillus altitudinis [Acc KF859970], comamonadaceae (Delftia) [Acc KF859971], and Stenotrophomonas maltophilia [Acc KF859973]). The bioavailability of some phytotoxic trace elements was also evaluated. Germination was inhibited when plants were grown without inoculation; however, no inhibition to the germination of maize was observed when bacterial consortium was added to oily sludge. A significant difference in the bioavailability of Cu and Zn was observed under maize rhizosphere oily sludge inoculated with consortium. Germination rate, protein, superoxide dismutase, and peroxidase in bacterial consortium–inoculated maize was higher in plants grown in oily sludge compared with plants grown in untreated sludge. The bacterial consortium suppressed the oxidative stress of plants grown in oily sludge and enhanced maize tolerance to oily sludge. The bacterial consortium can be used for enhancing plant nutrient uptake and to increase biochemical and plant enzymes and can be used by oil refineries to remediate soils contaminated with oily sludge.

Ecological-health risk assessment and bioavailability of potentially toxic elements (PTEs) in soil and plant around a copper smelter.

Soil and the dominant plant species in the vicinity of Khatoon Abad copper smelter in Kerman province of Iran are examined to determine contamination, bioavailability, and ecological-health risk of potentially toxic elements (PTEs) based on 23 collected soil samples and 13 Artemisia siebri plant species. Cu, Mo, As, and Sb display a significant level of enrichment in soil. Ecological risk assessment shows that Cu, As, and Cd pose the highest ecological risk. The results of PTEs fractionation reveal that, on average, Cu, As, Cd, Pb, Zn, and Mo are mostly distributed between non-residual fractions reflecting higher mobility and potential ecological risk, while Cr, Ni, and Co are significantly distributed within the residual fraction, and do not pose a serious ecological risk. Mobility factor suggests high bioavailability of Cu for plants followed by As, Cd, Pb, Mo, Co, Ni, and Cr. Biological accumulation coefficient displays higher phytoavailability of Mo and Cd. PTEs transfer within plant follows the order of Mo > As > Pb > Zn > Cu > Ni > Co > Cr > Cd. The results of phytoavailability indicate the high tendency of Cd to bioaccumulate in Artemisia's root, while Mo, As, and Pb tend to translocate towards Artemisia's shoot. Calculated hazard index and incremental lifetime cancer risk revealed that As poses the highest non-carcinogenic health risk, and As and Pb pose the greatest carcinogenic health risk in both adults and children.

Heavy metals speciation study revealing merits of anaerobic co-disposal of municipal solid waste with discrete paper mill sludges: An experimental investigation in simulated landfill bioreactors

Speciation of heavy metals (Cu, Cr, Pb, Ni, Cd and Zn) during anaerobic co-disposal of two distinct paper mill sludges viz. effluent treatment plant sludge and de-inking plant sludge with municipal solid waste in anaerobic landfill bioreactor was investigated. Effects of moisture content, volatile solids and pH on fractionation of heavy metals over the course of landfilling were also analyzed. Study revealed enhancement in bioavailability of Cu, Cr, Ni and Cd on sole disposal municipal solid waste in bioreactor landfill over 300 days. However, co-disposal of effluent treatment plant sludge with municipal solid waste showed reduction in bioavailability of every analyzed heavy metals with maximum increment in stable residual forms of Cu, Cr, Pb, Ni and Zn by 3.70 %, 0.73 %, 3.08 %, 1.17 % and 3.45 % (dry weight), respectively. De-inking sludge co-disposal was also found effective for reducing bioavailability of Cu, Cd and Zn while bioavailability of Cr, Ni and Pb was unaltered. Strong correlations between increase in residual forms of heavy metals and volatile solid reduction obtained for both co-disposed bioreactors.

Effects of Replacing Inorganic with Respective Complexed Glycinate Minerals on Apparent Mineral Bioavailability and Deposition Rate in Tissues of Broiler Breeders.

The study was conducted to evaluate the effects of replacing inorganic trace minerals (ITMs) with respective low-dose complexed glycinate minerals (CGMs) on their bioavailability and retention during peak laying period of broiler breeders. In this experiment, 648 ZhenNing broiler breeders (23weeks old) were randomly allocated to four treatments with six replicates (27 birds/replicate) and fed for 14weeks including 2weeks adaptation period. The treatments were T1-ITM, commercially recommended levels of ITMs (Cu, Zn, Fe, and Mn sulphates); T2-MIX, half of the minerals were supplemented with ITMs and half with CGMs; T3-L-CGMs, minerals were supplemented with CGMs (50% level of T1); and T4-M-CGMs, minerals were supplemented with CGMs (70% level of T1). The results showed that birds fed on ITM had lower bioavailability of Fe, Mn, and Zn (P < 0.05) than those fed on L-CGMs, but the highest (P < 0.01) bioavailability of Cu was found in those fed on MIX. Mineral retention (in serum, muscle, bone, and tissues) was not affected by reducing supplementation levels of trace minerals up to 50% of ITMs, but Zn (in serum, liver, kidney, heart, and albumen) and Fe (in serum and the yolk) retention was negatively affected (P < 0.05). In conclusion, replacing dietary ITMs with low-dose complexed glycinate minerals increases the apparent bioavailability of Fe, Mn, and Zn without compromising the mineral retention rates in most of the tissues tested.

PM2.5-bound potentially toxic elements (PTEs) fractions, bioavailability and health risks before and after coal limiting.

Fractions, bioavailability, health risks of fine particulate maters (PM2.5)-bound potentially toxic elements (PTEs) (Pb, Cd, Cr, Cu and Zn) were investigated before and after coal limiting in Baoding city. The winter PM2.5 samples were collected at different functional areas such as residential area (RA), industrial area (IA), suburb (SB), street (ST) and Botanical Garden Park (BG) in 2016 (coal dominated year) and 2017 (gas dominated year). The fractions and bioavailability of PTEs were determined and evaluated based on BCR sequential extraction. Health risks through inhalation exposure were evaluated by US EPA health risk assessment model. The results from different years and functional areas were compared and discussed. The fractions and bioavailability of PM2.5-bound PTEs varied with functional areas. The percentages of cadmium (Cd) and zinc (Zn) in acid-soluble fraction (F1-Cd and F1-Zn) to the total amount of Cd and Zn were low in BG samples (p<0.05). Bioavailability of Cd were high in SB samples (p<0.05). Total contents of PM-bound PTEs in 2017 generally decreased compared with 2016. The differences of fraction and bioavailability between 2016 and 2017 depended on the elements and areas. Higher proportions of copper (Cu) in acid-soluble fraction (F1-Cu) and bioavailability of Cu (p<0.05) were found in 2017 samples. Significant differences were found just at IA and RA for Pb, Cd and Zn. Our results indicated that the health risks from inhalation exposure for PTEs in PM2.5 declined about 11%-52% after the coal limiting in this city.

Speciation, Transformation, and Accumulation of Manure-derived Cu and Zn in the Soil–Rice System

ABSTRACTPig manure has been successfully utilized as organic fertilizer to field crops in China. In this study, we used the cement pool plot test to investigate the speciation change and bioavailability of Cu and Zn derived from different pig manures (the fresh pig manure [FM1], the composting pig manure [FM2], and the dry-fermentation-bed pig manure [FM3]) in a soil–rice system. Results showed that the soil pH and the carbon content increased after applying pig manures. Cu and Zn contents in soil also remarkably increased but maintained under the safety standards (except Cu content in FM3). The exchangeable and carbonate-associated Cu and Zn both decreased over time, whereas Cu and Zn in Fe-Mn oxide form and organic-bound state increased and were the dominating components in soil. The pig manures, especially FM2, improved the rice biomass and yield. However, FM3 caused high Cu and Zn accumulation in rice. Moreover, the Cu level in grain exceeded the Chinese food hygiene standard, but the Zn level remained under the safety concentration. Collectively, it is imperative to assess the potential risk of Cu and Zn originated from pig manures. Cu more easily exceeded the safety standard than Zn, although Zn levels can reach the limit concentration with continuous manure application.

A field study of vertical mobility and relative bioavailability of Cu and Ni in calcareous soil

ABSTRACT The vertical mobility of heavy metals in the soil profile may affect their bioavailability. In the present study, a field experiment was conducted for 11 years to investigate the vertical mobility of copper (Cu) and nickel (Ni) and the effects on their bioavailability in soil. It was found that the type and concentration of heavy metals are factors that affect mobility. After 11 years, the mobility and movement of Ni were greater than that of Cu from topsoil (0–20 cm) to subsoil (20–60 cm). The vertical mobility of Cu decreased with the increased addition of Cu, while Ni had the highest vertical mobility when its concentration was the highest in soil. The aging processes and vertical movement could lead to decreases in Cu availability (68–78%) and Ni availability (83–89%). For the decrease of Cu availability in soil, the main driving factor was the vertical movement at low added concentrations, but gradually became aging processes with the increase of added Cu concentrations, while Ni had the opposite tendency. Compared with Cu, aging and vertical mobility played a more prominent role in decreasing the bioavailability of Ni, the bioavailability of Cu changed less than that of Ni after 11 years. The decreased rate of Cu in wheat grains was about 0.26–1.05% while that of Ni was about 2.48–9.46% per year from 2009 to 2018. Therefore, the influence of the vertical downward movement of heavy metals should not be ignored in the assessment of the risk and bioavailability of heavy metals in soil.