Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition...Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition in wind and spreading minerals during vehicle transportation,respectively.In each zone,soil samples were collected.Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods.The results indicate that the average contents of Zn,Pb,Cd,Cu and As in soils are 508.6,384.8,7.53,356 and 44.6 mg/kg,respectively.But the contents of heavy metals in different zone have distinct differences.The proportion of oxidizing association with organic substance is small.Difference of the association of heavy metals is small in different polluted zones.展开更多
The concentration and speciation of six heavy metals in sediments of eight sampling sites of Haihe River were investigated. The metals, namely Cd, Cu, Co, Ni, Mn and Pb were considered. By using sequential extraction(...The concentration and speciation of six heavy metals in sediments of eight sampling sites of Haihe River were investigated. The metals, namely Cd, Cu, Co, Ni, Mn and Pb were considered. By using sequential extraction(SE), the total metals were divided into five fractions: exchangeable, carbonate bound, iron/manganese oxide bound, sulfides and organic matter fraction and residual fraction. A multivariate statistical approach(principal component analysis, PCA) was used to evaluate the contamination of heavy metals by the total levels and chemical forms, respectively. The results showed that the total metals concentration(TMC) could not provide sufficient and accurate information because the mobility, bioavailability and toxicity of metals depend not only on their total concentration but also on the physicochemical form in which they occur.展开更多
This study used a flame atomic absorption spectrometer (FAAS) and atomic fluorescence spec-trophotometer (AFS) to detect the concentrations of chromium (Cr), cadmium (Cd), lead (Pb), hy-drargyrum (Hg) and arsenic (As)...This study used a flame atomic absorption spectrometer (FAAS) and atomic fluorescence spec-trophotometer (AFS) to detect the concentrations of chromium (Cr), cadmium (Cd), lead (Pb), hy-drargyrum (Hg) and arsenic (As) in soils and three genotypes of vegetables in greenhouse, as well as analyzed the physical and chemical properties of soils, including soil pH, soil organic matter (OM), basic nutrients, electrical conductivity (EC) and cation exchange capacity (CEC) in Guan- zhong areas, Shaanxi province, China. The results showed that comparing to subsoil, the sampled topsoil is enriched in Cr, Cd, Pb, As and Hg. Cd (0.83 - 3.17 mg·kg-1) and Hg (0.40 - 1.44 mg·kg-1) are exceeding the limited value stated in “the 2006 Greenhouse Vegetable Producing Environmental Quality Evaluation Standards” of 0.40 mg·kg-1 and 0.35 mg·kg-1 respectively. However, Nanzhuang greenhouse soil is within the limits. The heavy metal pollution index (HPI) of soil in Sanyuan (8.10) is the highest and in Dongzhang (4.23) is the lowest. The contents of Pb (0.201 - 0.376 mg·kg-1) were exceeding the limited value (0.20 mg·kg-1) in vegetables species, and Cd (0.0363 - 0.0572 mg·kg-1) in some place were also exceeding the limited value (0.05 mg·kg-1). Greenhouse soils were becoming acidified year after year;the ratios of N, P and K in soil were seriously imbalanced. According to the impacting factors, OM, pH, available P, EC and CEC have obviously effected the accumulation of Cr and Hg. However, there was not enough evidence for the effects of available nitrogen and available potassium.展开更多
The concentrations of cadmium, copper, lead and zinc in sediment samples from the Vridi Canal (Harbour area of economic capital of Cote d’Ivoire) were determined to evaluate the level of contamination. All metal conc...The concentrations of cadmium, copper, lead and zinc in sediment samples from the Vridi Canal (Harbour area of economic capital of Cote d’Ivoire) were determined to evaluate the level of contamination. All metal concentrations in sediment samples, except Cu, were greater than the concentration of Upper Continental Crust (UCC). Sediment pollution assessment was undertaken by using Enrichment Factor (EF), geoaccumulation index (I<sub>geo</sub>) and Pollution Load Index (PLI). The enrichment factor (Cd: EF = 20.04;Pb: EF = 3.43;Zn: EF = 1.56) and géoaccumulation index (Cd: I<sub>geo</sub> = 4.29;Pb: I<sub>geo</sub> = 1.81) showed that the sediments were polluted. The Pollution Load Index (PLI > 1) indicated that the sediments of the studied area were heavily contaminated. Based on the comparison with sediment quality guidelines, the concentrations of cadmium, lead and zinc would be toxic to one or more species of aquatic organisms living in the sediments.展开更多
The contents of Pb, Cd, Cr, As, and Hg was investigated in the neighboring areas of a lead smelting enterprise and the metals contamination of soil was evaluated with the methodologies of the single factor index and N...The contents of Pb, Cd, Cr, As, and Hg was investigated in the neighboring areas of a lead smelting enterprise and the metals contamination of soil was evaluated with the methodologies of the single factor index and Nemerow integrated index. It is found that the content of heavy metals in the neighboring areas has no obvious difference from the reference points. And the soil contamination of heavy metals varies by elements, the contamination index follows the pollution order: Cd>Hg>Cr>As>Pb. The pollution degree of Cd is at high level and Hg at low level, but Cr and As reached the warning level. Therefore, the lead smelting enterprises should not only control lead but also other heavy metals as Cd.展开更多
[Objective]The research aimed to analyze the contents of heavy metals in the typical fruits of Nanning and evaluate the pollution status of heavy metals in fruits of Nanning. [Method]Five kinds of typical fruits( litc...[Objective]The research aimed to analyze the contents of heavy metals in the typical fruits of Nanning and evaluate the pollution status of heavy metals in fruits of Nanning. [Method]Five kinds of typical fruits( litchi,longan,dragon fruit,mangosteen and pineapple) in Nanning were collected to measure contents of heavy metals including Cd,Pb,As and Hg. According to standard of pollution-free fruits( GB18406. 2- 2001),pollution evaluation was conducted,and cumulative degrees of different fruits on a variety of heavy metals were contrasted. [Result] The heavy metal contents of all fruits were qualified. Comprehensive pollution index of dragon fruit was the maximum,and its cumulative capability on various heavy metals was the strongest. [Conclusion]The pollution degrees of all fruits were safety in Nanning,and pollution level was clean.展开更多
The germination and metal translocation ability of two sunflower seedlings were compared to identify the cultivar differences towards metal contamination at juvenile stage. The heavy metal treatments include: 0, 50, 1...The germination and metal translocation ability of two sunflower seedlings were compared to identify the cultivar differences towards metal contamination at juvenile stage. The heavy metal treatments include: 0, 50, 100, 150 and 200 mM Ni, Cd and Pb applied in sand filled pots to Hysun-33 and FH-533 sunflower. The highest germination percentage (79%) and vigor index were recorded for Hysun-33 with no heavy metal treatment. Pb and Cd treatments reduced the growth attributes of 20 days old seedlings of both the cultivars. The Ni translocation effectively enhanced the shoot and root biomass of Hysun-33. The high concentration of 150 and 200 mM Cd and Pb drastically reduced Mn and K contents, vigor, length and biomass of two sunflower cultivars. Among three of the heavy metals, Cd was found more toxic than Pb and Ni. Roots of 20 days old seedlings of Hysun-33 were able to hold more Cd metal and stop its translocation to epigenous parts. Although 150 and 200 mM Ni effects the germination and vigor of sunflower cultivars more than 50 and 100 mM Ni, it is found less toxic in comparison to Cd and Pb. The Cd accumulation in roots suggests that it is physiologically most active sink for Cd metal while epigenous parts of sunflower cultivars are sink for Pb and Ni metal as shoot of sunflower cultivars accumulates high contents of Pb and Ni.展开更多
This study assessed sediment contamination by heavy metals and pesticide active ingredients linked to chemical inputs used in agricultural activities in the lower Ouémé. Pesticide residues from the organochl...This study assessed sediment contamination by heavy metals and pesticide active ingredients linked to chemical inputs used in agricultural activities in the lower Ouémé. Pesticide residues from the organochlorine, pyrethroid and organophosphorus families were investigated by gas chromatography, and heavy metals (Cd, Pb, As, Ni, Zn, Fe, Mg, Cr and Hg) by atomic absorption spectrophotometry. The metallic pollution indices, the contamination factor (CF) and the ecological risk index were calculated. The results revealed 8 active ingredients in the rainy season and 9 in the dry season. Glyphosate was the active ingredient with the highest concentration at all stations, 9.65 ± 0.84 mg/kg recorded in the dry season at the Aguigadji station. All glyphosate values were above the EQS. DDT, Atrazine and Endosulfan also showed high concentrations in the dry and rainy seasons. Emamectin, Abamectin and Lambda Cyhalothrin also showed high concentrations in the dry season at Aguigadji, Ahlan and Sele. Only glyphosate was recorded at the control station (Toho), but in very low concentrations. Lead showed the highest concentrations at all the stations, 265.96 ± 21.02 mg/Kg in the rainy season and 255.38 ± 79.09 mg/Kg in the dry season, all detected at the Aguigadji station and above the EQS. Zn, Ni, Fe, Cu and Cr were all representative in both the dry and rainy seasons at the contaminated stations. Manganese showed high concentrations in the rainy season. Pb showed very high contamination (FC ≥ 6) at the Aguigadji and Ahlan stations and significant contamination (3 ≤ FC 6) at the Sele station in both the rainy and dry seasons. Ni, Hg and Cd, showed either moderate or significant contamination at the contaminated stations. The risk values showed a considerable ecological Ri (190 ≤ Ri < 380) in the rainy season and a moderate ecological Ri (95 ≤ Ri < 190) in the dry season at these contaminated stations.展开更多
Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific samp...Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10<sup>-4</sup> mg/L;2.2 × 10<sup>-1</sup> mg/L;1.2 × 10<sup>-4</sup> mg/L;2 × 10<sup>-4</sup> mg/L), Cadmium (4.4 × 10<sup>-5</sup> mg/L;1.1 × 10<sup>-2</sup> mg/L;10<sup>-4</sup> mg/L;4 × 10<sup>-4</sup> mg/L). Then Copper (7 × 10<sup>-4</sup> mg/L;3 × 10<sup>-3</sup> mg/L;7 × 10<sup>-4</sup> mg/L;1 × 10<sup>-4</sup> mg/L), Iron (1.51 mg/L;6.4 × 10<sup>-1</sup> mg/L;2.0012 mg/L;2.9 × 10<sup>-1</sup> mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10<sup>-3</sup> mg/L;1.5 × 10<sup>-3</sup> mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.展开更多
5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content ...5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects.展开更多
Monitoring of heavy metals contamination of agricultural products and their transfer and bioaccumulation in crops like rice has become a hot topic worldwide over the last two decades. The present study was carried out...Monitoring of heavy metals contamination of agricultural products and their transfer and bioaccumulation in crops like rice has become a hot topic worldwide over the last two decades. The present study was carried out to determine the accumulation of heavy metals in rice fields and their transfer to rice grains. Soil, irrigation water and rice grains samples were gathered in Maga-Pouss, Far-North, Cameroon. Concentrations of six heavy metals (lead, cadmium, zinc, copper, iron and mercury) were evaluated by Atomic Absorption Spectrophotometer (AAS). Mercury was not detected in this study. Average concentrations of metals were in this order (in mg/kg): Fe (188.60 ± 97.06) > Pb (63.63 ± 7.11) > Cd (2.59 ± 0.29) > Zn (1.10 ± 1.05) > Cu (0.80 ± 0.73) in water and Pb (105.50 ± 31.11) > Fe (105.50 ± 31.11) > Cu (45.93 ± 14.39) > Zn (22.52 ± 6.40) > Cd (3.15 ± 0.49) in soil. Water in Maga-Pouss rice fields appears to be more harmful than the soil, notably for lead, cadmium and copper. In rice grains, heavy metals were found in this order (mg/kg): Fe (188.01 ± 82.62) > Cu (27.20 ± 0.00) > Zn (23.61 ± 12.42) > Pb (19.50 ± 19.91) > Cd (2.02 ± 1.05). The mean bioconcentration factor (BCF) of metals from soil to rice grains was in the following order: Fe (2.60) > Zn (1.05) > Cd (0.64) > Cu (0.59) > Pb (0.18). From water to rice grains, the order is: Cu (37.26) > Zn (22.49) > Cd (6.97) > Pb (2.74) > Fe (1.94). Rice field pH and electrical conductivity favored the uptake of lead, copper and cadmium by rice grains. The findings of this study will be good documentation for risk assessment, and decision-making by environmental managers in this region.展开更多
Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-te...Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-term effects on economy,environment,and society.This study collected soil samples from 16 sample points including a control point to examine the pollution degrees and spatial distribution of heavy metals,as well as ecological and health risks associated with heavy metal pollution in the Ijero-Ekiti mining site,Nigeria.Geographical Information System(GIS)and remote sensing technologies were used to identify regions with high concentrations of heavy metals and assess the environmental impact of gold mining activities.The results show that the mean heavy metal concentrations of 16 soil pointa are 8.94(±5.97)mg/kg for As,0.18(±0.54)mg/kg for Cd,0.11(±1.06)mg/kg for Co,14.32(±3.43)mg/kg for Cr,6.89(±0.64)mg/kg for Cu,48.92(±11.77)mg/kg for Fe,135.81(±30.75)mg/kg for Mn,5.92(±0.96)mg/kg for Ni,5.72(±1.66)mg/kg for Pb,and 13.94(±1.38)mg/kg for Zn.The study reveals that heavy metal concentration in soils follows the order of Mn>Fe>Cr>Zn>As>Cu>Ni>Pb>Co>Cd.An analysis of soil samples indicates that 3 principal components(PCs)account for 70.008%of the total variance and there are strong positive correlations between various pairs of heavy metals.The total potential ecological risk index(309.599)in the study area is high.Non-carcinogenic risk suggests that there may be long-term health impacts on people who work in the mining areas due to chronic exposure to the environment.Based on the study,the hazard index of carcinogenic health risks associated with heavy metals through ingestion is 520.00×10^(–4).Dermal contact from As and Cr also increases the risk of cancer,with the highest hazard index value of 18.40×10^(–4).The lowest exposure pathway,with the hazard index value of 0.68×10^(–4),indicates that the inhalation of heavy metals has a comparatively low risk of cancer.This study recommends the formulation of policies to monitor the Ijero-Ekiti mining site and other regions in Nigeria where indiscriminate artisanal gold mining activities exist.展开更多
The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the ...The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the theory of groundwater circulation and solid-liquid equilibrium,a simple and easy-touse flux model of soil heavy metals migrating to groundwater is constructed.Based on groundwater environmental capacity,an innovative method for evaluating the harm of heavy metals in soil to groundwater is proposed,which has been applied in Hunchun Basin,Jilin Province,China.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn,Cu,As,Pb,Cd,Ni,and Hg in descending order.The content of heavy metals in groundwater(As,Hg,Cu,Pb,Zn,Ni,and Cd)in most areas has not risen to the threshold of environmental capacity within 10 years.The harm levels of soil heavy metals to groundwater in the most townships soils are at the moderate level or below.This evaluation method can quantify the flux of soil heavy metals into groundwater simply and quickly,determine the residual capacity of groundwater to heavy metals,evaluate the harm level of soil heavy metals to groundwater,provide support for relevant departments to carry out environmental protection of soil and groundwater,and provide a reference to carry out similar studies for related scholars.展开更多
Current globalization trends and important breakthroughs globally need a complete study of heavy metal contamination, its causes, its impacts on human and environmental health, and different remediation strategies. He...Current globalization trends and important breakthroughs globally need a complete study of heavy metal contamination, its causes, its impacts on human and environmental health, and different remediation strategies. Heavy metal pollution is mostly produced by urbanization and industry, which threatens ecosystems and human health. Herein, we discuss a sustainable environmental restoration strategy employing phytoremediation for heavy metal pollution, the carcinogenic, mutagenic, and cytotoxic effects of heavy metals such as cadmium, copper, mercury, selenium, zinc, arsenic, chromium, lead, nickel, and silver, which may be fatal. Phytoremediation, which was prioritized, uses plants to remove, accumulate, and depollute pollutants. This eco-friendly method may safely collect, accumulate, and detoxify toxins using plants, making it popular. This study covers phytostabilization, phytodegradation, rhizodegradation, phytoextraction, phytovolatilization, and rhizofiltration. A phytoremediation process’s efficiency in varied environmental circumstances depends on these components’ complex interplay. This paper also introduces developing phytoremediation approaches including microbe-assisted, chemical-assisted, and organic or bio-char use. These advancements attempt to overcome conventional phytoremediation’s limitations, such as limited suitable plant species, location problems, and sluggish remediation. Current research includes machine learning techniques and computer modeling, biostimulation, genetic engineering, bioaugmentation, and hybrid remediation. These front-line solutions show that phytoremediation research is developing towards transdisciplinary efficiency enhancement. We acknowledge phytoremediation’s promise but also its drawbacks, such as site-specific variables, biomass buildup, and sluggish remediation, as well as ongoing research to address them. In conclusion, heavy metal pollution threatens the ecology and public health and must be reduced. Phytoremediation treats heavy metal pollution in different ways. Over time, phytoremediation systems have developed unique ways that improve efficiency. Despite difficulties like site-specificity, sluggish remediation, and biomass buildup potential, phytoremediation is still a vital tool for environmental sustainability.展开更多
The objective of this study was to establish a baseline for future studies that aim to determine possible contamination from human, agricultural and industrial activities. As well as the determination of the indices o...The objective of this study was to establish a baseline for future studies that aim to determine possible contamination from human, agricultural and industrial activities. As well as the determination of the indices of environmental or geological contamination and enrichment factors of heavy metals Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in agricultural soils of Constanza, Jarabacoa, Rancho Arriba and San José de Ocoa (SJO), municipalities located in the valleys of the Central mountain range of the Dominican Republic. The determination of the concentrations of heavy metals was carried out using the X-ray Fluorescence technique. Just like in Azua, San Juan de la Maguana (SJM) y Barahona in the southwest. Producer municipalities of vegetables, rice, beans, corn, melon, watermelon, tomato, banana, avocado, sugar cane and fodder for cattle. The concentration of 160 mg·kg<sup>-1</sup> Probable Effect Level (PEL) of Cr according to the SQuiRTs table (USEPA-NOAA) for agricultural soils, were exceeded in 50% of the samples in SJM, SJO, Jarabacoa and Constanza;in Barahona and Azua by 20%. The PEL of 42.8 mg·kg-1</sup><sup></sup> of the Ni was higher in more than 50% of the samples from SJM, Azua, Barahona and Jarabacoa;in SJO and Constanza at 35%. In the case of Cu with a PEL of 108 mg·kg-1</sup><sup></sup> in SJO and Constanza, 5% of the samples exceeded its, in the other areas the concentrations were lower. Zn, As and Pb did not manage to exceed their respective PEL.展开更多
The roads in correlation with the traffic linked to their existences are at the origin of the emission of numerous polluting substances likely to induce disturbances of the growth and the behavioral changes in the org...The roads in correlation with the traffic linked to their existences are at the origin of the emission of numerous polluting substances likely to induce disturbances of the growth and the behavioral changes in the organisms living in their vicinities. The purpose of this study is to analyze the growth and capacity accumulation of a common earthworm species (Millsonia omodeoi) in Cu, Cr, Ni, Pb and Zn in soils along a main road called “Autoroute du Nord” in C?te d’Ivoire. Thus, the earthworms were harvested in soils from a distance of 0 m (just after the sidewalk) to a distance of 200 m from the toll highway and in a control soil sampled in Lamto reserve (C?te d’Ivoire). The study was carried out in the soil laboratory at the ecological station of Lamto reserve. The Ford-Walford technique was used to determine the model and parameters most appropriated for describing the growth of earthworms. A pairwise comparison of the growth parameters was carried out using the Kruskal-Wallis test with the STATISTICA 7.1 software. The heavy metals contained in the cultivated soils and earthworms were detected and quantified using a Scanning Electron Micro-scope (MEB FEG Supra 40 VP Zeiss) and an Atomic Absorption Spectrometer SPECTRA 110 (VARIAN). The capacity accumulation of heavy metals in earthworm was determined by the bioaccumulation factor (BAF) calculation. The results of this study showed that Gompertz is the most appropriated model to describe the growth of M. omodeoi. The life cycle of M. omodeoi shows that this earthworm adopts a K type demographic strategy. Cu is the most accumulated heavy metals in M. omodeoi, when Cr is the least accumulated. Concerning heavy metal content in the earthworms, it decreases while moving away from the pavement. These results highlight a possibility of choice of M. omodeoi as 1) indicators of heavy metals pollution and 2) target of biological organisms for environmental impact studies.展开更多
In 2019, an investigation by the U.S. House of Representatives revealed major infant food conglomerates had products with high levels of arsenic, lead, cadmium, and mercury, posing concerns for infants’ vulnerability...In 2019, an investigation by the U.S. House of Representatives revealed major infant food conglomerates had products with high levels of arsenic, lead, cadmium, and mercury, posing concerns for infants’ vulnerability to the neurotoxic effects of these metals. Trends of laboratory-detected heavy metals were analyzed in children aged zero to five from 1999-2020, providing insights on heavy metal contamination in infant food products. Utilizing National Health and Nutrition Examination Survey (NHANES) data, mean heavy metal levels in children were calculated, considering gender, race, and income-to-poverty ratio as proxies for assessing associations with increasing heavy metal rates in infant food. Findings indicated an overall decrease in mean concentrations over time, though remaining elevated. Black children exhibited higher lead levels than the overall average, while the Asian subgroup displayed higher levels of total blood mercury and cadmium levels. Lack of internal standards in regulatory bodies, particularly the FDA, exacerbates the issue, with no legally enforceable guidelines or strict maximum levels for heavy metals in infant foods. Urgent FDA interventions are needed, addressing contamination at the sources of raw materials, implementing transparent and extensive product testing, and comprehensive manufacturer labeling to inform consumers about elevated heavy metal levels in infant products.展开更多
This paper aims to assess soil fertility and risk contamination parameters in response to increased amendment rates of sewage sludge application,under semi-arid climatic conditions of Morocco,using two soil textures:s...This paper aims to assess soil fertility and risk contamination parameters in response to increased amendment rates of sewage sludge application,under semi-arid climatic conditions of Morocco,using two soil textures:soil A(clay-silty)and soil B(sandy-clay)over two years.To this end,sewage sludge and soils treatments physicochemical parameters,heavy metals content,degree of pollution and associated risks were evaluated and compared to controlled soils.The results showed that all studied parameters changed significantly(p<0.05)in a dose-dependent manner for both soils compared to the untreated control soils.Indeed,there were significant increase in organic matter(OM),total organic carbon(TOC)and nutrients content(N,P and K)of both sols as a response to increased sewage sludge amendment rates.Overall,sewage sludge application showed a positive agronomic potential for both soil and plant.However,there were concern about some heavy metals contamination risks,the results showed a gradual increase of heavy metals concentration in this order:Cu>Pb>Zn>Ni>Cd>Cr.Nevertheless,their concentrations were below the critical values established by the European Union for the agronomic use of soil.The obtained results of assessed parameters indicating SS degree of pollution and associated risks showed a low to a moderate contamination risks of heavy metals.Accordingly,environmental risks of sewage sludge application will be related to increase of heavy metals mainly in a long-term agricultural reuse.Thus,optimal management of sewage sludge application is recommended to ensure sustainability and benefits at the same time to master the contamination risks.展开更多
The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant life. The poll...The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant life. The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant living beings. This study focuses on the pollution of sediments of the Chari and Logon rivers in the city of N’Djamena by heavy metals. The objective of this study is to evaluate the degree of contamination, the geo-accumulation index and the degree of the Pollutant Loading Index of some heavy metals (Pb, Cr, Cu, Mn and Cd) and iron in the sediments of the sampled sites. The average concentrations of heavy metals and iron in the sediments are: Pb (10.00 ± 00 μg/Kg to 126 ± 16.52 μg/Kg);Cr VI (0.13 ± 00 mg/Kg to 0.21 ± 00 mg/Kg);Cd (trace);Cu (0.08 ± 0.02 mg/kg to 3.23 ± 0.64 mg/kg);Fe (0.25 ± 0.00 mg/kg to 5.79 ± 0.00 mg/kg);and Mn (0.2 ± 0.00 mg/Kg to 1.1 ± 0.00 mg/Kg);in order of highest to lowest abundance: Fe > Mn > Cd > Cu > Cr VI > Pb for the Logon;Fe > Cu > Mn > Cd > Cr VI > Pb for the Chari and Fe > Mn > Cu > Cd > Cr VI > Pb for the Confluent. The contamination factors for all heavy metals range from no contamination to low contamination for the sediments analyzed. The geo-accumulation indices indicate that the sampled sites are not polluted. The same is true for Er and RI which confirm an absence of ecological risks in the analyzed sediments.展开更多
基金Porject(50474050)supported by the Natural Science Foundation of ChinaProject(2006BAK04B01-2)supported by the National Key Technology R&D Program of China
文摘Depending upon the polluted features of various mining activities in a typical nonferrous metal mine,the contaminated soil area was divided into four zones which were polluted by tailings,mine drainage,dust deposition in wind and spreading minerals during vehicle transportation,respectively.In each zone,soil samples were collected.Total 28 soil samples were dug and analyzed by ICP-AES and other relevant methods.The results indicate that the average contents of Zn,Pb,Cd,Cu and As in soils are 508.6,384.8,7.53,356 and 44.6 mg/kg,respectively.But the contents of heavy metals in different zone have distinct differences.The proportion of oxidizing association with organic substance is small.Difference of the association of heavy metals is small in different polluted zones.
文摘The concentration and speciation of six heavy metals in sediments of eight sampling sites of Haihe River were investigated. The metals, namely Cd, Cu, Co, Ni, Mn and Pb were considered. By using sequential extraction(SE), the total metals were divided into five fractions: exchangeable, carbonate bound, iron/manganese oxide bound, sulfides and organic matter fraction and residual fraction. A multivariate statistical approach(principal component analysis, PCA) was used to evaluate the contamination of heavy metals by the total levels and chemical forms, respectively. The results showed that the total metals concentration(TMC) could not provide sufficient and accurate information because the mobility, bioavailability and toxicity of metals depend not only on their total concentration but also on the physicochemical form in which they occur.
文摘This study used a flame atomic absorption spectrometer (FAAS) and atomic fluorescence spec-trophotometer (AFS) to detect the concentrations of chromium (Cr), cadmium (Cd), lead (Pb), hy-drargyrum (Hg) and arsenic (As) in soils and three genotypes of vegetables in greenhouse, as well as analyzed the physical and chemical properties of soils, including soil pH, soil organic matter (OM), basic nutrients, electrical conductivity (EC) and cation exchange capacity (CEC) in Guan- zhong areas, Shaanxi province, China. The results showed that comparing to subsoil, the sampled topsoil is enriched in Cr, Cd, Pb, As and Hg. Cd (0.83 - 3.17 mg·kg-1) and Hg (0.40 - 1.44 mg·kg-1) are exceeding the limited value stated in “the 2006 Greenhouse Vegetable Producing Environmental Quality Evaluation Standards” of 0.40 mg·kg-1 and 0.35 mg·kg-1 respectively. However, Nanzhuang greenhouse soil is within the limits. The heavy metal pollution index (HPI) of soil in Sanyuan (8.10) is the highest and in Dongzhang (4.23) is the lowest. The contents of Pb (0.201 - 0.376 mg·kg-1) were exceeding the limited value (0.20 mg·kg-1) in vegetables species, and Cd (0.0363 - 0.0572 mg·kg-1) in some place were also exceeding the limited value (0.05 mg·kg-1). Greenhouse soils were becoming acidified year after year;the ratios of N, P and K in soil were seriously imbalanced. According to the impacting factors, OM, pH, available P, EC and CEC have obviously effected the accumulation of Cr and Hg. However, there was not enough evidence for the effects of available nitrogen and available potassium.
文摘The concentrations of cadmium, copper, lead and zinc in sediment samples from the Vridi Canal (Harbour area of economic capital of Cote d’Ivoire) were determined to evaluate the level of contamination. All metal concentrations in sediment samples, except Cu, were greater than the concentration of Upper Continental Crust (UCC). Sediment pollution assessment was undertaken by using Enrichment Factor (EF), geoaccumulation index (I<sub>geo</sub>) and Pollution Load Index (PLI). The enrichment factor (Cd: EF = 20.04;Pb: EF = 3.43;Zn: EF = 1.56) and géoaccumulation index (Cd: I<sub>geo</sub> = 4.29;Pb: I<sub>geo</sub> = 1.81) showed that the sediments were polluted. The Pollution Load Index (PLI > 1) indicated that the sediments of the studied area were heavily contaminated. Based on the comparison with sediment quality guidelines, the concentrations of cadmium, lead and zinc would be toxic to one or more species of aquatic organisms living in the sediments.
文摘The contents of Pb, Cd, Cr, As, and Hg was investigated in the neighboring areas of a lead smelting enterprise and the metals contamination of soil was evaluated with the methodologies of the single factor index and Nemerow integrated index. It is found that the content of heavy metals in the neighboring areas has no obvious difference from the reference points. And the soil contamination of heavy metals varies by elements, the contamination index follows the pollution order: Cd>Hg>Cr>As>Pb. The pollution degree of Cd is at high level and Hg at low level, but Cr and As reached the warning level. Therefore, the lead smelting enterprises should not only control lead but also other heavy metals as Cd.
基金Supported by Key Item of Guangxi Natural Science Fund in 2013,China(2013GXNSFEA053001)
文摘[Objective]The research aimed to analyze the contents of heavy metals in the typical fruits of Nanning and evaluate the pollution status of heavy metals in fruits of Nanning. [Method]Five kinds of typical fruits( litchi,longan,dragon fruit,mangosteen and pineapple) in Nanning were collected to measure contents of heavy metals including Cd,Pb,As and Hg. According to standard of pollution-free fruits( GB18406. 2- 2001),pollution evaluation was conducted,and cumulative degrees of different fruits on a variety of heavy metals were contrasted. [Result] The heavy metal contents of all fruits were qualified. Comprehensive pollution index of dragon fruit was the maximum,and its cumulative capability on various heavy metals was the strongest. [Conclusion]The pollution degrees of all fruits were safety in Nanning,and pollution level was clean.
文摘The germination and metal translocation ability of two sunflower seedlings were compared to identify the cultivar differences towards metal contamination at juvenile stage. The heavy metal treatments include: 0, 50, 100, 150 and 200 mM Ni, Cd and Pb applied in sand filled pots to Hysun-33 and FH-533 sunflower. The highest germination percentage (79%) and vigor index were recorded for Hysun-33 with no heavy metal treatment. Pb and Cd treatments reduced the growth attributes of 20 days old seedlings of both the cultivars. The Ni translocation effectively enhanced the shoot and root biomass of Hysun-33. The high concentration of 150 and 200 mM Cd and Pb drastically reduced Mn and K contents, vigor, length and biomass of two sunflower cultivars. Among three of the heavy metals, Cd was found more toxic than Pb and Ni. Roots of 20 days old seedlings of Hysun-33 were able to hold more Cd metal and stop its translocation to epigenous parts. Although 150 and 200 mM Ni effects the germination and vigor of sunflower cultivars more than 50 and 100 mM Ni, it is found less toxic in comparison to Cd and Pb. The Cd accumulation in roots suggests that it is physiologically most active sink for Cd metal while epigenous parts of sunflower cultivars are sink for Pb and Ni metal as shoot of sunflower cultivars accumulates high contents of Pb and Ni.
文摘This study assessed sediment contamination by heavy metals and pesticide active ingredients linked to chemical inputs used in agricultural activities in the lower Ouémé. Pesticide residues from the organochlorine, pyrethroid and organophosphorus families were investigated by gas chromatography, and heavy metals (Cd, Pb, As, Ni, Zn, Fe, Mg, Cr and Hg) by atomic absorption spectrophotometry. The metallic pollution indices, the contamination factor (CF) and the ecological risk index were calculated. The results revealed 8 active ingredients in the rainy season and 9 in the dry season. Glyphosate was the active ingredient with the highest concentration at all stations, 9.65 ± 0.84 mg/kg recorded in the dry season at the Aguigadji station. All glyphosate values were above the EQS. DDT, Atrazine and Endosulfan also showed high concentrations in the dry and rainy seasons. Emamectin, Abamectin and Lambda Cyhalothrin also showed high concentrations in the dry season at Aguigadji, Ahlan and Sele. Only glyphosate was recorded at the control station (Toho), but in very low concentrations. Lead showed the highest concentrations at all the stations, 265.96 ± 21.02 mg/Kg in the rainy season and 255.38 ± 79.09 mg/Kg in the dry season, all detected at the Aguigadji station and above the EQS. Zn, Ni, Fe, Cu and Cr were all representative in both the dry and rainy seasons at the contaminated stations. Manganese showed high concentrations in the rainy season. Pb showed very high contamination (FC ≥ 6) at the Aguigadji and Ahlan stations and significant contamination (3 ≤ FC 6) at the Sele station in both the rainy and dry seasons. Ni, Hg and Cd, showed either moderate or significant contamination at the contaminated stations. The risk values showed a considerable ecological Ri (190 ≤ Ri < 380) in the rainy season and a moderate ecological Ri (95 ≤ Ri < 190) in the dry season at these contaminated stations.
文摘Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10<sup>-4</sup> mg/L;2.2 × 10<sup>-1</sup> mg/L;1.2 × 10<sup>-4</sup> mg/L;2 × 10<sup>-4</sup> mg/L), Cadmium (4.4 × 10<sup>-5</sup> mg/L;1.1 × 10<sup>-2</sup> mg/L;10<sup>-4</sup> mg/L;4 × 10<sup>-4</sup> mg/L). Then Copper (7 × 10<sup>-4</sup> mg/L;3 × 10<sup>-3</sup> mg/L;7 × 10<sup>-4</sup> mg/L;1 × 10<sup>-4</sup> mg/L), Iron (1.51 mg/L;6.4 × 10<sup>-1</sup> mg/L;2.0012 mg/L;2.9 × 10<sup>-1</sup> mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10<sup>-3</sup> mg/L;1.5 × 10<sup>-3</sup> mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, gala super and glycel clearly indicates that these surface waters are subject to agricultural contamination.
文摘5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects.
文摘Monitoring of heavy metals contamination of agricultural products and their transfer and bioaccumulation in crops like rice has become a hot topic worldwide over the last two decades. The present study was carried out to determine the accumulation of heavy metals in rice fields and their transfer to rice grains. Soil, irrigation water and rice grains samples were gathered in Maga-Pouss, Far-North, Cameroon. Concentrations of six heavy metals (lead, cadmium, zinc, copper, iron and mercury) were evaluated by Atomic Absorption Spectrophotometer (AAS). Mercury was not detected in this study. Average concentrations of metals were in this order (in mg/kg): Fe (188.60 ± 97.06) > Pb (63.63 ± 7.11) > Cd (2.59 ± 0.29) > Zn (1.10 ± 1.05) > Cu (0.80 ± 0.73) in water and Pb (105.50 ± 31.11) > Fe (105.50 ± 31.11) > Cu (45.93 ± 14.39) > Zn (22.52 ± 6.40) > Cd (3.15 ± 0.49) in soil. Water in Maga-Pouss rice fields appears to be more harmful than the soil, notably for lead, cadmium and copper. In rice grains, heavy metals were found in this order (mg/kg): Fe (188.01 ± 82.62) > Cu (27.20 ± 0.00) > Zn (23.61 ± 12.42) > Pb (19.50 ± 19.91) > Cd (2.02 ± 1.05). The mean bioconcentration factor (BCF) of metals from soil to rice grains was in the following order: Fe (2.60) > Zn (1.05) > Cd (0.64) > Cu (0.59) > Pb (0.18). From water to rice grains, the order is: Cu (37.26) > Zn (22.49) > Cd (6.97) > Pb (2.74) > Fe (1.94). Rice field pH and electrical conductivity favored the uptake of lead, copper and cadmium by rice grains. The findings of this study will be good documentation for risk assessment, and decision-making by environmental managers in this region.
文摘Artisanal gold mining,a labor-intensive and antiquated technique,is a growing industry and the source of income for rural communities all over the world.However,artisanal gold mining has potential negative and long-term effects on economy,environment,and society.This study collected soil samples from 16 sample points including a control point to examine the pollution degrees and spatial distribution of heavy metals,as well as ecological and health risks associated with heavy metal pollution in the Ijero-Ekiti mining site,Nigeria.Geographical Information System(GIS)and remote sensing technologies were used to identify regions with high concentrations of heavy metals and assess the environmental impact of gold mining activities.The results show that the mean heavy metal concentrations of 16 soil pointa are 8.94(±5.97)mg/kg for As,0.18(±0.54)mg/kg for Cd,0.11(±1.06)mg/kg for Co,14.32(±3.43)mg/kg for Cr,6.89(±0.64)mg/kg for Cu,48.92(±11.77)mg/kg for Fe,135.81(±30.75)mg/kg for Mn,5.92(±0.96)mg/kg for Ni,5.72(±1.66)mg/kg for Pb,and 13.94(±1.38)mg/kg for Zn.The study reveals that heavy metal concentration in soils follows the order of Mn>Fe>Cr>Zn>As>Cu>Ni>Pb>Co>Cd.An analysis of soil samples indicates that 3 principal components(PCs)account for 70.008%of the total variance and there are strong positive correlations between various pairs of heavy metals.The total potential ecological risk index(309.599)in the study area is high.Non-carcinogenic risk suggests that there may be long-term health impacts on people who work in the mining areas due to chronic exposure to the environment.Based on the study,the hazard index of carcinogenic health risks associated with heavy metals through ingestion is 520.00×10^(–4).Dermal contact from As and Cr also increases the risk of cancer,with the highest hazard index value of 18.40×10^(–4).The lowest exposure pathway,with the hazard index value of 0.68×10^(–4),indicates that the inhalation of heavy metals has a comparatively low risk of cancer.This study recommends the formulation of policies to monitor the Ijero-Ekiti mining site and other regions in Nigeria where indiscriminate artisanal gold mining activities exist.
基金supported by the project of China Geology Survey(12120115032801,DD20190340)。
文摘The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the theory of groundwater circulation and solid-liquid equilibrium,a simple and easy-touse flux model of soil heavy metals migrating to groundwater is constructed.Based on groundwater environmental capacity,an innovative method for evaluating the harm of heavy metals in soil to groundwater is proposed,which has been applied in Hunchun Basin,Jilin Province,China.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn,Cu,As,Pb,Cd,Ni,and Hg in descending order.The content of heavy metals in groundwater(As,Hg,Cu,Pb,Zn,Ni,and Cd)in most areas has not risen to the threshold of environmental capacity within 10 years.The harm levels of soil heavy metals to groundwater in the most townships soils are at the moderate level or below.This evaluation method can quantify the flux of soil heavy metals into groundwater simply and quickly,determine the residual capacity of groundwater to heavy metals,evaluate the harm level of soil heavy metals to groundwater,provide support for relevant departments to carry out environmental protection of soil and groundwater,and provide a reference to carry out similar studies for related scholars.
文摘Current globalization trends and important breakthroughs globally need a complete study of heavy metal contamination, its causes, its impacts on human and environmental health, and different remediation strategies. Heavy metal pollution is mostly produced by urbanization and industry, which threatens ecosystems and human health. Herein, we discuss a sustainable environmental restoration strategy employing phytoremediation for heavy metal pollution, the carcinogenic, mutagenic, and cytotoxic effects of heavy metals such as cadmium, copper, mercury, selenium, zinc, arsenic, chromium, lead, nickel, and silver, which may be fatal. Phytoremediation, which was prioritized, uses plants to remove, accumulate, and depollute pollutants. This eco-friendly method may safely collect, accumulate, and detoxify toxins using plants, making it popular. This study covers phytostabilization, phytodegradation, rhizodegradation, phytoextraction, phytovolatilization, and rhizofiltration. A phytoremediation process’s efficiency in varied environmental circumstances depends on these components’ complex interplay. This paper also introduces developing phytoremediation approaches including microbe-assisted, chemical-assisted, and organic or bio-char use. These advancements attempt to overcome conventional phytoremediation’s limitations, such as limited suitable plant species, location problems, and sluggish remediation. Current research includes machine learning techniques and computer modeling, biostimulation, genetic engineering, bioaugmentation, and hybrid remediation. These front-line solutions show that phytoremediation research is developing towards transdisciplinary efficiency enhancement. We acknowledge phytoremediation’s promise but also its drawbacks, such as site-specific variables, biomass buildup, and sluggish remediation, as well as ongoing research to address them. In conclusion, heavy metal pollution threatens the ecology and public health and must be reduced. Phytoremediation treats heavy metal pollution in different ways. Over time, phytoremediation systems have developed unique ways that improve efficiency. Despite difficulties like site-specificity, sluggish remediation, and biomass buildup potential, phytoremediation is still a vital tool for environmental sustainability.
文摘The objective of this study was to establish a baseline for future studies that aim to determine possible contamination from human, agricultural and industrial activities. As well as the determination of the indices of environmental or geological contamination and enrichment factors of heavy metals Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in agricultural soils of Constanza, Jarabacoa, Rancho Arriba and San José de Ocoa (SJO), municipalities located in the valleys of the Central mountain range of the Dominican Republic. The determination of the concentrations of heavy metals was carried out using the X-ray Fluorescence technique. Just like in Azua, San Juan de la Maguana (SJM) y Barahona in the southwest. Producer municipalities of vegetables, rice, beans, corn, melon, watermelon, tomato, banana, avocado, sugar cane and fodder for cattle. The concentration of 160 mg·kg<sup>-1</sup> Probable Effect Level (PEL) of Cr according to the SQuiRTs table (USEPA-NOAA) for agricultural soils, were exceeded in 50% of the samples in SJM, SJO, Jarabacoa and Constanza;in Barahona and Azua by 20%. The PEL of 42.8 mg·kg-1</sup><sup></sup> of the Ni was higher in more than 50% of the samples from SJM, Azua, Barahona and Jarabacoa;in SJO and Constanza at 35%. In the case of Cu with a PEL of 108 mg·kg-1</sup><sup></sup> in SJO and Constanza, 5% of the samples exceeded its, in the other areas the concentrations were lower. Zn, As and Pb did not manage to exceed their respective PEL.
文摘The roads in correlation with the traffic linked to their existences are at the origin of the emission of numerous polluting substances likely to induce disturbances of the growth and the behavioral changes in the organisms living in their vicinities. The purpose of this study is to analyze the growth and capacity accumulation of a common earthworm species (Millsonia omodeoi) in Cu, Cr, Ni, Pb and Zn in soils along a main road called “Autoroute du Nord” in C?te d’Ivoire. Thus, the earthworms were harvested in soils from a distance of 0 m (just after the sidewalk) to a distance of 200 m from the toll highway and in a control soil sampled in Lamto reserve (C?te d’Ivoire). The study was carried out in the soil laboratory at the ecological station of Lamto reserve. The Ford-Walford technique was used to determine the model and parameters most appropriated for describing the growth of earthworms. A pairwise comparison of the growth parameters was carried out using the Kruskal-Wallis test with the STATISTICA 7.1 software. The heavy metals contained in the cultivated soils and earthworms were detected and quantified using a Scanning Electron Micro-scope (MEB FEG Supra 40 VP Zeiss) and an Atomic Absorption Spectrometer SPECTRA 110 (VARIAN). The capacity accumulation of heavy metals in earthworm was determined by the bioaccumulation factor (BAF) calculation. The results of this study showed that Gompertz is the most appropriated model to describe the growth of M. omodeoi. The life cycle of M. omodeoi shows that this earthworm adopts a K type demographic strategy. Cu is the most accumulated heavy metals in M. omodeoi, when Cr is the least accumulated. Concerning heavy metal content in the earthworms, it decreases while moving away from the pavement. These results highlight a possibility of choice of M. omodeoi as 1) indicators of heavy metals pollution and 2) target of biological organisms for environmental impact studies.
文摘In 2019, an investigation by the U.S. House of Representatives revealed major infant food conglomerates had products with high levels of arsenic, lead, cadmium, and mercury, posing concerns for infants’ vulnerability to the neurotoxic effects of these metals. Trends of laboratory-detected heavy metals were analyzed in children aged zero to five from 1999-2020, providing insights on heavy metal contamination in infant food products. Utilizing National Health and Nutrition Examination Survey (NHANES) data, mean heavy metal levels in children were calculated, considering gender, race, and income-to-poverty ratio as proxies for assessing associations with increasing heavy metal rates in infant food. Findings indicated an overall decrease in mean concentrations over time, though remaining elevated. Black children exhibited higher lead levels than the overall average, while the Asian subgroup displayed higher levels of total blood mercury and cadmium levels. Lack of internal standards in regulatory bodies, particularly the FDA, exacerbates the issue, with no legally enforceable guidelines or strict maximum levels for heavy metals in infant foods. Urgent FDA interventions are needed, addressing contamination at the sources of raw materials, implementing transparent and extensive product testing, and comprehensive manufacturer labeling to inform consumers about elevated heavy metal levels in infant products.
文摘This paper aims to assess soil fertility and risk contamination parameters in response to increased amendment rates of sewage sludge application,under semi-arid climatic conditions of Morocco,using two soil textures:soil A(clay-silty)and soil B(sandy-clay)over two years.To this end,sewage sludge and soils treatments physicochemical parameters,heavy metals content,degree of pollution and associated risks were evaluated and compared to controlled soils.The results showed that all studied parameters changed significantly(p<0.05)in a dose-dependent manner for both soils compared to the untreated control soils.Indeed,there were significant increase in organic matter(OM),total organic carbon(TOC)and nutrients content(N,P and K)of both sols as a response to increased sewage sludge amendment rates.Overall,sewage sludge application showed a positive agronomic potential for both soil and plant.However,there were concern about some heavy metals contamination risks,the results showed a gradual increase of heavy metals concentration in this order:Cu>Pb>Zn>Ni>Cd>Cr.Nevertheless,their concentrations were below the critical values established by the European Union for the agronomic use of soil.The obtained results of assessed parameters indicating SS degree of pollution and associated risks showed a low to a moderate contamination risks of heavy metals.Accordingly,environmental risks of sewage sludge application will be related to increase of heavy metals mainly in a long-term agricultural reuse.Thus,optimal management of sewage sludge application is recommended to ensure sustainability and benefits at the same time to master the contamination risks.
文摘The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant life. The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant living beings. This study focuses on the pollution of sediments of the Chari and Logon rivers in the city of N’Djamena by heavy metals. The objective of this study is to evaluate the degree of contamination, the geo-accumulation index and the degree of the Pollutant Loading Index of some heavy metals (Pb, Cr, Cu, Mn and Cd) and iron in the sediments of the sampled sites. The average concentrations of heavy metals and iron in the sediments are: Pb (10.00 ± 00 μg/Kg to 126 ± 16.52 μg/Kg);Cr VI (0.13 ± 00 mg/Kg to 0.21 ± 00 mg/Kg);Cd (trace);Cu (0.08 ± 0.02 mg/kg to 3.23 ± 0.64 mg/kg);Fe (0.25 ± 0.00 mg/kg to 5.79 ± 0.00 mg/kg);and Mn (0.2 ± 0.00 mg/Kg to 1.1 ± 0.00 mg/Kg);in order of highest to lowest abundance: Fe > Mn > Cd > Cu > Cr VI > Pb for the Logon;Fe > Cu > Mn > Cd > Cr VI > Pb for the Chari and Fe > Mn > Cu > Cd > Cr VI > Pb for the Confluent. The contamination factors for all heavy metals range from no contamination to low contamination for the sediments analyzed. The geo-accumulation indices indicate that the sampled sites are not polluted. The same is true for Er and RI which confirm an absence of ecological risks in the analyzed sediments.
