Mg Kg-1 For Cd Research Articles

Assessment of heavy metal levels in cow's milk and associated health risks in the vicinity of the MIDROC Laga Dambi gold mine in Ethiopia

IntroductionThe possible health effects of consuming milk contaminated with heavy metals have been the subject of considerable concern worldwide. ObjectiveThe aim of this study was to determine the level of heavy metals in cow's milk in the vicinity of MIDROC Laga Dambi gold mine and to assess their possible health risks for consumers. MethodsNine composite samples were formed by aggregating 243 milk samples obtained in triplicates from 81 domestic milk-producing households. Inductively coupled plasma-optical emission spectroscopy was used to measure the amount of heavy metals after samples digestion under optimal conditions. ResultsThe heavy metals concentrations obtained were 13.913˗7.843, 9.505˗3.589, 5.972˗3.147, 2.288˗1.851, 0.403˗0.143, 0.436˗0.128, 0.26˗0.153, 0.143˗0.048, 0.160˗ND (not detected), and 0.140˗ND mgkg−1for Fe, Zn, Pb, Mn, Hg, Cr, Cd, As, Ni, and Co, respectively. Of the heavy metals identified, the levels of Pb, As, Cd, and Hg exceeded the recommended value. Based on the estimated daily intake (EDI), the total health quotient (THQ) is higher than unity even for Pb alone. It has been found that the consumption of cow milk increases the health index (HI) by 2.972. Ninety five percent of the HI in the study area was explained by the toxic heavy metals (Pb, Cd, As, and Hg) in the cow milk, which were found to be beyond the safe limit. ConclusionThis demonstrates that there is a health risk to the population who consume cow’s milk sourced from the vicinity of MIDROC Laga Dambi gold mine. To safeguard the public’s health, we advised strict monitoring and legislative control for the safety of cow’s milk originating from study area.

Ecotoxicity of Cadmium along the Soil-Cotton Plant-Cotton Bollworm System: Biotransfer, Trophic Accumulation, Plant Growth, Induction of Insect Detoxification Enzymes, and Immunocompetence.

Cadmium (Cd) is a hazardous element that may jeopardize environmental safety and human health through biotransfer and trophic accumulation. Here, we tested Cd toxicity on cotton plants, cotton bollworms, and their responses. Results demonstrated that Cd accumulated in plant roots, aerial parts, insect larvae, pupae, and frass in a dose-dependent pattern. The ∼9.35 mg kg-1 of Cd in plant aerial parts, ∼3.68 in larvae, ∼6.43 in pupae, and high transfer coefficient (∼5.59) indicate significant mobility. The ∼19.61 mg kg-1 of Cd in larvae frass suggests an effective detoxification strategy, while BAFcotton (∼1.14) and BAFworm (∼0.54) indicated low bioaccumulation. Cadmium exposure resulted in compromised plant growth and yield as well as alterations in photosynthetic pigment contents, antioxidant enzyme activities, and certain life history traits of cotton bollworms. Furthermore, carboxylesterase activity and encapsulation rates of insect larvae decreased with increasing Cd concentrations, whereas acetylcholinesterase, phenol oxidase, glutathione S-transferase, and multifunctional oxidase exhibited hormesis responses.

Influence of Anthropogenic Pollution on Soil and Plants of Gosa Dumpsite, Abuja, Nigeria

Despite increased awareness of the causes of environmental pollution, it continues to pose a serious threat to both developed and developing countries worldwide. The Gosa dumpsite in Abuja serves as a receptacle for various waste materials from both high and low-income areas of the metropolis. Surprisingly, peri-urban farmers residing in the vicinity still cultivate edible crops on this polluted land. This study aims to assess the impact of waste dumping at Gosa dumpsite on selected soil properties and the uptake of heavy metals by plants. In order to achieve this objective, soil and plant samples were collected from established 5 x 5 m2 quadrants during the early and late dry as well as rainy seasons of 2019 and 2020. The collected samples underwent analysis using standard methods to determine their physical and chemical properties. Additionally, the study identified the dominant plant species within the dumpsite through standard methods. The findings revealed that the dumpsite soil exhibited characteristics of loamy sand, with the highest pH value of 8.85 ± 0.90 recorded during the dry season of 2020. Other significant soil results included total nitrogen at 1.09 ± 0.64 g kg-1, organic carbon at 9.88 ± 0.10 g kg-1, Cd at 11.93 ± 2.25 mg kg-1, Hg at 2.18 ± 1.08 mg kg-1, and Pb at 54.68 ± 8.68 mg kg-1, all of which were observed during the early rainy season of 2020. During the remaining seasons considered, lower values were obtained. Notably, these values exceeded the permissible levels set by the FAO for soil intended for cultivating edible crops. Furthermore, the plant species Ageratum conyzoides demonstrated the highest uptake of heavy metals, with concentrations of 4.47 ± 1.15 mg kg-1 for Cd, 1.77 ± 1.08 mg kg-1 for Hg, and 19.56 ± 4.83 mg kg-1 for Pb, all recorded during the early dry season of 2020. In conclusion, although the Gosa dumpsite in Abuja may appear fertile enough for cultivation, the study's results highlight that it cannot be deemed suitable for the production of edible crops. The presence of heavy metals and other pollutants in the soil poses a significant risk to crop health and, consequently, to human consumption.

Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy.

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg−1 dw) and REEs (447.3 ± 52.8 ng g−1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg−1 dw) and high-risk (9.14 mg kg−1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g−1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg−1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

Cd uptake and translocation by camelthorn (Alhagi maurorum Medik): a promising approach for phytoremediation of Cd-contaminated soils.

Camelthorn (Alhagi maurorum Medik) is a desert plant that can withstand a variety of abiotic challenges, including water stress and harsh weather, making it potentially useful for cleaning cadmium (Cd) from contaminated soils. The current study aims to determine the degree of plant tolerance to Cd toxicity and the possibility of using it in the phytoremediation of Cd-contaminated soils. Camelthorn plants were cultivated in soil polluted with Cd at doses of 0, 25, 50, 100, and 200 mg kg-1. The growth, nutrient uptake, Cd concentrations, and some biochemical compounds were determined to study the response of camelthorn plants to Cd stress. Exposure of camelthorn plants to 200 mg kg-1 of Cd inhabited the synthesis of leaf-chlorophyll by 49% compared to the control and reduced the concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe), and zinc (Zn) by 43, 36, 43, 50, 67, and 36%, respectively. Camelthorn plants can tolerate up to 11 mg kg-1 of available soil Cd, 65 mg kg-1 in the root, and 22 mg kg-1 in the shoot before experiencing Cd toxicity. Camelthorn plants increased the levels of carbohydrates, total phenols, and proline compounds that were used in the scavenging of reactive oxygen species (ROS). Moreover, the plants increased the activity of antioxidant enzymes, i.e., superoxide dismutase (SOD) and peroxidase (POD), to mitigate the oxidative stress caused by Cd toxicity. The root-shoot transfer (TF) of Cd varied between 0.27 to 0.48, while the bioaccumulation factor (BAF) varied between 1.2 and 2.32. Camelthorn plants have a BAF value higher than 1 and a TF value lower than 1. Camelthorn plants accumulate Cd in the roots with low root-shoot transfer and are suitable for phytostabilization technology. Camelthorn plants have a potent antioxidant defense against the toxicity of Cd, and this finding is a good tool in the remediation of Cd-contaminated soil.

Heavy Metals Pollution of Agricultural Soils near Industrial Complexes in Jeon-Nam Regions of Korea

Monitoring heavy metal concentrations in agricultural soils near industrial area is very important due to food safety. The aim of this study was to assess the heavy metal concentrations, pollution index (PI), and pollution load index (PLI) in agricultural soils close to industrial complexes in Jeon-Nam province. Fifteen industrial complexes in Jeon-Nam province were selected (Yeongam, Muan, Yeonggwang, Hampyeong, Gangjin, Wando, Haenam, Jindo, Jangseong, Damyang, Boseong, Goheung, Hwasun, Gokseong, and Gurye). Five agricultural fields each were selected at each industrial complex within 500 meter and 1,000 meter radius at each industrial complexe boundaries, respectively. Two depth of soil samples (0 - 15 cm depth for top soil and 15 - 30 cm depth for sub soil) were collected in spring of 2020 before planting. Soil samples were analyzed for seven heavy metals, including arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Heavy metal concentrations for both top and sub soil ranged from 1.7 to 8.6 mg kg-1 for As, from 0.3 to 0.9 mg kg-1 for Cd, from 13.3 to 67.8 mg kg-1 for Cr, from 8.9 to 20.7 mg kg-1 for Cu, from 7.0 to 28.1 mg kg-1 for Ni, from 7.0 to 31.8 mg kg-1 for Pb, from 62.6 to 143.9 mg kg-1 for Zn. Heavy metal concentrations in studied soils were not higher than the levels of Soil Contamination Warning Standard (SCWS). Pollution index (PI) and pollution load index (PLI) values of all seven heavy metals including As, Cd, Cr, Cu, Ni, Pb, and Zn ranged from 0.1 to 0.7 for PI and from 0.14 to 0.30 for PLI. Both values were less than 1. Therefore, these soils are classified uncontaminated for PI and unpolluted for PLI. Overall, all soil samples did not exceed the level limits of Soil Environment Conservation Law (SECL).Descriptive statistics of heavy metals concentration in agricultural soils near the industrial complexes in Jeon-Nam province in Korea. Element† As (mg kg-1) Cd (mg kg-1) Cr (mg kg-1) Cu (mg kg-1) Ni (mg kg-1) Pb (mg kg-1) Zn (mg kg-1) Soil depth Top Sub Top Sub Top Sub Top Sub Top Sub Top Sub Top Sub Average 4.5 4.8 0.6 0.6 27.7 27.7 13.9 13.6 12.8 13.1 13.3 13.7 96.9 95.2 Min. 0.0 0.6 0.1 0.2 1.7 2.3 1.5 2.2 1.2 1.5 0.0 2.9 32.6 33.9 Max. 13.8 16.9 1.3 1.3 128.8 116.1 33.9 40.0 52.6 46.1 65.9 82.5 206.8 187.0 Stdev. 2.4 2.7 0.2 0.2 17.4 16.5 6.3 6.2 7.2 6.9 8.3 9.5 34.8 33.6 C.V. (%) 52.9 56.9 36.2 38.5 62.9 59.4 45.3 45.9 56.0 53.0 62.3 69.4 35.9 35.3 Kurtosis 1.6 3.9 0.9 0.8 9.1 6.8 0.7 2.4 8.2 5.3 13.7 22.5 0.4 0.2 Skweness 1.0 1.4 0.7 0.8 2.3 2.0 0.9 1.2 2.2 1.8 3.0 3.9 0.8 0.8 SCWS limit 25 4 n/a 150 100 200 300 Number of above SCWS 0 0 0 0 0 0 0 †Min., minimum; Max., maximum; Stdev., standard deviation; C.V., coefficients variations. Soil Contamination Warning Standard (SCWS) from Ministry of Environment (MOE) in Korea.

Effects of cadmium contamination on bacterial and fungal communities in Panax ginseng-growing soil

BackgroundCadmium (Cd) contamination in soil poses a serious safety risk for the development of medicine and food with ginseng as the raw material. Microorganisms are key players in the functioning and service of soil ecosystems, but the effects of Cd-contaminated ginseng growth on these microorganisms is still poorly understood. To study this hypothesis, we evaluated the effects of microorganisms and Cd (0, 0.25, 0.5, 1.0, 2.0, 5.0, and 10.0 mg kg-1 of Cd) exposure on the soil microbial community using Illumina HiSeq high-throughput sequencing.ResultsOur results indicated that Cd-contaminated soil affected the soil microbial diversity and composition, and bacterial diversity was affected more than fungal diversity in Cd-contaminated soil, especially according to Shannon indices. The abundance of the soil microbial community decreased and the composition changed according to the relative abundances at the phylum level, including those of Saccharibacteria and Gemmatimonadetes in bacteria and Mortierellomycota in fungi. The LEfSe algorithm was used to identify active biomarkers, and 45 differentially abundant bacterial taxonomic clades and 16 differentially abundant fungal taxonomic clades were identified with LDA scores higher than 4.0. Finally, a heatmap of Spearman's rank correlation coefficients and canonical discriminant analysis (CDA) indicated that some key biomarkers, Arenimonas, Xanthomonadales, Nitrosomonadaceae, Methylophilales, Caulobacterales, Aeromicrobium, Chitinophagaceae, Acidimicrobiales, Nocardioidaceae, Propionibacteriales, Frankiales, and Gemmatimonadaceae, were positively correlated with the total and available Cd (p<0.05) but negatively correlated with AK, AP, and pH (p<0.05) in the bacterial community. Similarly, in the fungal community, Tubaria, Mortierellaceae, and Rhizophagus were positively correlated with the total and available Cd but negatively correlated with AK, AP, TK, and pH.ConclusionCd contamination significantly affected microbial diversity and composition in ginseng-growing soil. Our findings provide new insight into the effects of Cd contamination on the microbial communities in ginseng-growing soil.

Save our soil from heavy metals (Pb and Cd) accumulation for rice growth

Rice intensification has been very successful in Indonesia and was even appreciated by FAO in 1985. However, despite the success, paddy soils are frequently polluted with Pb and Cd which are mostly derived from phosphate (P) fertilizers. Considering that the soils have been used for the long-term cultivation, Pb and Cd contents both in the soil and rice have exceeded the tolerance level in food as defined by WHO namely 2 and 0.24 mg kg-1, respectively. The highest Pb and Cd were found in soils cultivated for 80 years in Musi Rawas, Indonesia with values of 20.56 mg kg-1 and 0.72 mg kg-1 for soil and 3.11 mg kg-1 and 0.29 mg kg-1 for rice, while the lowest was found at 20 years with values of 17.82 mg kg-1 and 0.26 mg kg-1. Furthermore, the highest rice Pb and Cd were obtained at 80 years of cultivation with values of 3.11 and 0.29 mg kg-1, respectively, while the lowest was found at 20 years with values of 2.35 mg kg-1 Pb and 0.15 mg kg-1 Cd. Therefore, these metals need to be managed immediately. One of the methods to detoxify heavy metals is by application of organic material. Through a chelating process, heavy metals are immobilized and not absorbed by rice. Based on the results, rice straw biochar and compost at a rate of 10 tons ha-1 separately reduced Pb and Cd in soil from 13.60 to 3.00 mg kg-1 and 13.60 to 5.98 mg kg-1 for Pb and 0.62 down to 0.29 mg kg-1 and 0.64 down to 0.42 mg kg-1 for Cd, respectively.

Assessment of selected heavy metal concentrations in soils from a mining area in Minna, Niger state.

The study investigated the contents of selected heavy metals in top soils and sub-soils around the vicinity of artisanal gold mining site in Minna, Niger state, using standard procedures. Digestion was done using HNO3-H2O2-HCl and heavy metal content using atomic absorption spectrometer. The results obtained showed some extent of contamination with mean values of 2.87 ± 0.17mg kg-1, 286.21 ± 0.20mg kg-1, 15,375.46 ± 0.52mg kg-1, 2233.60 ± 0.46mg kg-1, and 131.71 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The surrounding environment (50m away from the gold mining site) also showed significant contamination with mean values of 2.77 ± 0.17mg kg-1, 295.27 ± 0.20mg kg-1, 11,523.64 ± 0.25mg kg-1, 1956.50 ± 0.54mg kg-1, and 74.63 ± 0.15mg kg-1 for Cd, Zn, Fe, Mn, and Pb, respectively. The values obtained were significantly higher when compared with those from the control soil samples. With the exception of Pb and Mn, the values of the other metals investigated were all below the WHO permissible limit. The trend of contamination with respect to contamination factor was in the order: Zn > Fe > Pb > Mn > Cd. The high contents of Pb and Mn in this area therefore show the need for more studies and immediate intervention measures.

Carbon and nitrogen stabile isotope ratio and heavy metals in Leccinum aurantiacum in a hybrid aspen plantation in agricultural land

Edible mycorrhizal fungi can be harvested in the fourth year after establishment of a hybrid aspen plantation in previous agricultural land at hemiboreal conditions. It is important to understand the role of fungi in element cycling at the ecosystem level as well as the amounts of elements, including heavy metals, that are accumulated in fruitbodies of edible fungi in the context of food safety. Therefore we evaluated the carbon and nitrogen stable isotope ratio and content of heavy metals (Cr, Pb, Mn, Ni, Cd, Cu and Zn) in Leccinum aurantiacum (Bull.) Gray in a juvenile hybrid aspen (Populus tremuloides Michx. × Populus tremula L.) plantation in agricultural land initially fertilised with biogas production residues (digestate), sewage sludge and wood ash, which are potential sources of pollution of heavy metals. The research site was established in the spring of 2011, but the natural occurrence of fruitbodies of L. aurantiacum was observed in 2014. The mean isotopic data for fruitbodies of L. aurantiacum, collected in the 2014–2018 monitoring period, ranged between -27.4 and -24.5‰ for δ13C and between 7.8 and 10.1‰ for δ15N. The mean content of investigated heavy metals in fruitbodies of L. aurantiacum were up to 129 mg kg-1 for Zn, up to 99 mg kg-1 for Cu, up to 30 mg kg-1 for Mn, up to 1.5 mg kg-1 for Ni, up to 1.7 mg kg-1 for Cd, up to 1.1 mg kg-1 for Cr and up to 0.6 mg kg-1 for Pb. We concluded that the application of digestate, sewage sludge and wood ash as fertilisers to improve soil quality in hybrid aspen plantations in agricultural land did not result in increased heavy metal accumulation in fruitbodies of L. aurantiacum, but N isotopic compositions were altered (15N-enriched) for a period of up to five years after application of the organic fertilizers (digestate and sewage sludge). &#x0D; &#x0D; Keywords: agricultural land, hybrid aspen, Leccinum aurantiacum (Bull.) Gray, heavy metals, stable isotope ratio

Phytoremediation capacity, growth and physiological responses of Crambe abyssinica Hochst on soil contaminated with Cd and Pb

The search for vegetal species regarding effectiveness in the phytoremediation of soils is of great importance, mainly in function of the great environmental problems, such as soil contamination with heavy metals, the necessity of producing more food, among others that mankind face today. This work aimed (i) to evaluate phytoremediation capacity of Crambe abyssinica Hochst and its growth in soil artificially contaminated with Cd and Pb, and (ii) to evaluate the possible impacts of crambe cultivation in contaminated soil conditions, in order to evaluate, to test, and to question the Brazilian CONAMA 420, providing important information that can be useful for governmental and environmental purposes. Two simultaneous experiments were developed, one for each metal. The soils were contaminated with salts of CdCl2 and PbCl2H2O in five doses based on the investigation values (IV) of CONAMA Resolution 420, resulting in 0; 1.5; 3; 9 and 30 mg kg−1 for Cd and 33; 90; 180; 540 and 1800 mg kg−1 for Pb. Gaseous exchange, development, nutritional composition and production of plant components, as well as phytoavailability of metals, were evaluated. The contamination with metals reduced photosynthesis, increased breathing as well as leading to a negative effect on the mineral nutrition and productivity in general; Plants cultivated in soil with Cd presented higher phytoavailability when compared to those cultivated in the Pb conditions, being found metals in all parts of the crambe plants from 1.5 mg kg− 1 of Cd in the soil; and Pb was retained only in roots, not being translocated in the plant. Cd showed higher phytoavailability, being found in all parts of the plant and Pb was retained only in the roots. Cd showed a higher phytoavailability when compared to Pb, also being found in all parts of crambe plants from dose 1.5 mg kg-1 of Cd in soil, which is an environmental problem, since in these concentrations the cultivation of crops is allowed by Brazilian legislation CONAMA 420.

Accumulation and distribution of cadmium and lead in 28 oilseed rape cultivars grown in a contaminated field.

Heavy metal pollution in soils has become an important concern for human health. Therefore, it is vital to develop suitable remediation strategies for contaminated soils. Oilseed rape tolerates high concentrations of heavy metals and is a promising candidate for the phytoextraction of cadmium (Cd) and lead (Pb) from metal-contaminated soils. A field experiment was conducted to evaluate 28 oilseed rape cultivars including Brassica napus L. and Brassica juncea L. for their ability to accumulate Cd and Pb. These cultivars were grown in a field co-contaminated with Cd (0.78 mg kg-1) and Pb (330 mg kg-1). The results showed that concentrations in shoots ranged from 1.22 to 3.01 mg kg-1 for Cd and from 10.8 to 29.5 mg kg-1 for Pb. Cadmium and Pb accumulations in shoots could reach 83.4 and 799 μg plant-1, respectively. The majority of translocation factors (TFs) for Cd (> 1.0) were higher than for Pb (≤ 1.0). However, concentrations of Cd and Pb in seeds were much lower, in the range of 0.04 to 0.21 mg kg-1 and 0.04 to 0.51 mg kg-1, respectively. The seed yields of oilseed rape varied from 1238 to 2904 kg ha-1, with a mean value of 2289 kg ha-1. Among the cultivars, three (OS-9, OS-12, and OS-15) were selected as Cd and Pb potential accumulators, with Cd accumulation in shoots being 2.74-3.70 times higher and Pb accumulation in shoots being 3.37-5.23 times higher as compared with the lowest accumulating cultivar. These selected cultivars (B. napus) have application potential for phytoextraction of Cd and Pb from polluted soils without stopping agricultural activities and accompanying food safety issues.

Tropical climate effect on the toxic heavy metal pollutant course of road-deposited sediments

In modern society, the intense vehicle traffic and the lack of effective mitigating strategies may adversely impact freshwater systems. Road-deposited sediments (RDS) accumulate a variety of toxic substances which are transported into nature during hydrologic events, mainly affecting water bodies through stormwater runoff. The aim of this study was to evaluate the RDS metal enrichment ratio between the end of wet season and the middle of the dry season for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in samples from Natal, Brazil. Twenty RDS, drainage system and river sediment samples were collected in the wet and dry seasons using a stainless-steel pan, brush and spatula. In the laboratory, the samples were submitted to acid digestion and heavy metal concentrations were measured by atomic absorption spectrometry (AAS). A consistent RDS enrichment by heavy metals in dry season samples was followed by an increase in the finest particle size fraction (D < 63 μm). Maximum concentrations were 5, ND, 108, 23810, 83, ND, 77 and 150 mg kg-1 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively. The RDS enrichment ratio was Cr(1.3 × ), Cu(2.6 × ), Fe(3.3 × ), Mn(1.5 × ), Pb(1.5 × ) and Zn(2.1 × ). The Geo-accumulation Index values showed that RDS were moderately polluted for Cu and slighted polluted for Zn and Pb. Principal Component Analysis (PCA) showed that the accumulation of toxic heavy metals decreased according to water flow.

Ultra-diluted Solutions of Nux vomica in the Remediation of Metals in Soils and Bioavailability for Soybeans

The aim of this study was to evaluate the homeopathic medicine Nux vomica in the remediation of soils contaminated with cadmium (Cd) and lead (Pb) and the bioavailability of these metals in soybean plants. To this end the soil was contaminated prior to sowing, using CdCl2H2O and PbCl2 salts in three rates, based on the resolution of the research values of resolution No. 420 of CONAMA, resulting in 0.0, 3.0 and 9.0 mg kg-1 for Cd and 89.0, 180.0 and 540.0 mg kg-1 for Pb. The homeopathic remedy Nux vomica was used in dynamizations 12, 24, 48, 96, 200 and 400 CH (Centesimal Hanhemannian), being the witness with distilled water. Medicines were applied to the soil seven days before sowing and after sowing, every 14 days applied in the plant until complete the cycle. During cultivation were evaluated development, gas exchange, nutrient composition, component production and bioavailability of metals in the plant. The results demonstrate that Nux vomica medicine interfered in height and stem diameter and CO2 assimilation, stomatal conductance and transpiration of soybean plants, but did not affect the bioavailability of metals to plants.

A simple method for evaluation of the total concentration of Cd, Cr, Cu, Pb and Zn in sediments from the São Gonçalo channel in Pelotas, RS, Brazil

This study evaluated the total concentrations of Cd, Cr, Cu, Pb and Zn in sediments samples from the Sao Goncalo channel, Patos-Mirim lagoon complex, RS state, Southern Brazil during 2013 autumn, winter and spring, and 2014 summer. Ultrasound-assisted extraction method was employed to extract metals from the sediment samples. The sample powder was mixed with HNO3 and HF in an ultrasonic bath during 60 minutes at 25 oC. The limits of detection were 0.002; 0.026; 0.83; 0.386 and 0.44 mg kg-1 for Cd, Cr, Cu, Pb and Zn, respectively. The accuracy of the method was confirmed by analysis of two sediment certified reference materials and its precision was determined by the values of relative standard deviation lower than 9.1%. The concentrations obtained ranged from 0.11 to 0.58 mg kg-1 for Cd; 14.7 to 38.4 mg kg-1 for Cr; 3.9 to 102.0 mg kg-1 for Cu; 1.6 to 3.11 mg kg-1 for Pb; and 29.3 to 126 mg kg-1 for Zn. These values did not exceed the probable effect levels (PEL). Simplicity, low cost and high efficiency are some of the qualities of the method, making it adequate for routine analysis.

Concentration levels of cadmium and lead in the raw and processed meat of Helix pomatia snails.

This work reports on cadmium and lead contaminations in the edible snail Helix pomatia harvested in Poland. One hundred and 24 samples of Helix pomatia meat collected from seven provinces (voivodeships) of Poland were analyzed for their trace metal levels by graphite furnace atomic absorption spectrometry (GFAAS). The research was conducted in 2 stages. The 1st stage analyzed snail meat prior to any further technological treatment (raw meat). In the 2nd stage, the trace element levels were measured in meat subjected to technological treatment (processed meat). The trace element contents in raw meat samples ranged from 0.06 mg kg-1 to 0.22 mg kg-1 for Cd and from 0.06 mg kg-1 to 0.18 mg kg-1 for Pb. The analyses revealed an increase in the cad- mium content from 0.12 mg kg-1 to 0.18 mg kg-1 in thermally treated snail meat and no changes in lead concentration during the two-stage heat treatment. Regulation (EC) 1881/2006 does not specify the Cd and Pb residue limits in meat of terrestrial edible snails. The limits are set for in- vertebrate aquatic organisms meat (i.e. shellfish, mollusc, cephalopod) and range from 0.5 mg/kg to 1.5 mg/kg of tissue fresh weight for Pb and from 0.5 mg kg -1 to 1 mg kg-1 for Cd (EU Commis- sion 2006). The results demonstrate that the land snail Helix pomatia has a tendency to bioaccu- mulate trace elements, and the cooking process is likely to affect (increase) the Cd content in the snail meat.

Seasonal toxicity variation in light-textured soil amended with urban sewage sludge: interaction effect on cadmium, nickel, and phytotoxicity.

Sewage sludge is increasingly used as an organic amendment to agricultural soils, especially to soils containing little organic matter. However, little is known on the impact of this biowaste on seasonal changes of nickel and cadmium toxicity in a sandy loam soil. Accordingly, the aim of this field-scale study was to evaluate the seasonal phytotoxicity according to Cd, Ni, and dehydrogenase variation in an agricultural soil during two successive annual amendments with increasing amounts of urban sludge (0, 40, 80, and 120t ha-1year-1). Sampling was carried out at the end of dry season (EDS) and at the end of wet season (EWS) during 2years 2012/2013. Sludge application significantly increased the amount of organic matter and dehydrogenase activity in the soil. In order to explain the seasonal variation of Cd and Ni, pH and electrical conductivity were also monitored in this study. The increased rate of sewage sludge addition slightly reduced the pH but soil remained above neutrality. The electrical conductivity which reflects soil salinity was strongly correlated with Cd and Ni content that increased with sludge dose. Salinity and heavy metals were highest at EDS 2013. In addition, soil phytotoxicity testing was performed by the evaluation of lettuce seed germination for 120h. Although heavy metal content did not generally exceed Tunisian thresholds (3 and 75mg kg-1 for Cd and Ni, respectively), the seed germination index decreased with sewage sludge dose at all seasons. In general, we observed a significant effect of seasonal variation for all studied parameters. Sewage sludge reuse could be a feasible way to improve soil organic matter but toxicity risks consistently increased with time.

Geochemical Background and Baseline Values Determination and Spatial Distribution of Heavy Metal Pollution in Soils of the Andes Mountain Range (Cajamarca-Huancavelica, Peru).

Concentrations of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and one metalloid (As) as well as various parameters (pH, organic carbon, granulometric analysis and cation exchange capacity) were analyzed in 77 soil samples collected in the mining areas of La Zanja and Colquirrumi (Department of Cajamarca) and Julcani (Department of Huancavelica). Our study proposed geochemical baseline values for heavy metals in a natural region (La Zanja) from samples collected during the period of the environmental impact study (2006), that is, from an earlier period which occurred at the beginning of the exploitation of the current gold mine. The baseline values obtained were as follows: 8.26 mg·kg−1 for Cr; 56.97 mg·kg−1 for Ni; 22, 20 mg·kg−1 for the Cu; 47.42 mg·kg−1 for Zn; 27.50 mg·kg−1 for As; 4.36 mg·kg−1 for Cd; 4.89 mg·kg−1 for Hg, and 44.87 mg·kg−1 for Pb. Through the use of different indices of heavy metal contamination (geo-accumulation index (Igeo), improved Nemerow index (IIN) and potential ecological risk index (RI)), the degree of pollution caused by mining activities in two areas, Colquirrumi and Julcani, which have a high density of mining sites in operation, was determined. The values obtained from these indices indicated that the Colquirrumi region was the most contaminated, followed by Julcani. The area of La Zanja, despite being free of mining operations, presented slight diffuse pollution. Several positive correlations were obtained, with a high level of significance, between pH, organic carbon content, cation exchange capacity, and the Cr, Pb and Ni concentrations of the soils. The spatial distribution of the heavy metals was realized by means of the interpolation method of ordinary kriging. The results obtained and the experience gained in this work were necessary to facilitate the identification of soil contamination processes in high altitude areas of the Andes Western Cordillera (Peru) as a basis for taking appropriate measures when restoring soils, during mine closure processes, and to protect the quality of soil resources.

Heavy metals bioconcentration from soil to vegetables and appraisal of health risk in Koka and Wonji farms, Ethiopia.

Heavy metal accumulation in agricultural crops has grown a major concern globally as a result of a significant health impact on human. The quantification of heavy metals (Cd, Pb, Cr, Zn, Cu, and Ni) in the soil and vegetables at two sites (Koka and Wonji Gefersa) was done using flame atomic absorption spectrophotometer. The mean concentrations of heavy metals in vegetable fields' soil samples obtained from Koka were higher for Pb, Cr, Zn, Cu, and Ni. The overall results of soil samples ranged 0.52-0.93, 13.6-27.3, 10.0-21.8, 44.4-88.5, 11.9-30.3, and 14.7-34.5mgkg-1 for Cd, Pb, Cr, Zn, Cu, and Ni, respectively. The concentrations of heavy metals were maximum for Cd (0.41±0.03mgkg-1), Pb (0.54±0.11mgkg-1), Zn (14.4±0.72mgkg-1), Cu (2.84±0.27mgkg-1), and Ni (1.09±0.11mgkg-1) in Cabbage and for Cr (2.63±0.11mg kg-1) in green pepper. The result indicated that Cd has high transfer factor value and Pb was the lowest. The transfer pattern for heavy metals in different vegetables showed a trend in the order: Cd > Zn > Cu > Cr > Ni > Pb. Among different vegetables, cabbage showed the highest value of metal pollution index and bean had the lowest value. Hazard index of all the vegetables was less than unity; thus, the consumption of these vegetables is unlikely to pose health risks to the target population.

English

Determination of the levels of heavy metals in sewage sludge is necessary prior to application of the sludge to agriculture because of the inherent risk of heavy metal toxicity to soil, plants and humans. The heavy metals (Cu, Cd, Pb and Zn) in sewage sludge were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES) following extraction with modified-BCR and ultrasonic assisted-BCR extraction methods. The quantities of heavy metals obtained from the two extraction methods were compared. The ICP-OES results indicated that in the exchangeable fraction in both extraction methods the amount of zinc released ranged from 19-227 mg kg-1, and this represented the highest concentration of metals in this fraction. Clarifier sludge contained more zinc (2375 mg kg-1) than raw sludge (310 mg kg-1). An improvement in the amount of zinc (120.8 mg kg-1) and lead (98.7 mg kg-1) released in the reducible fraction in raw sludge samples was obtained with UA-BCR extraction. UA-BCR showed that the raw sludge contained about 17 mg kg-1 of Cd while only about 0.625 mg kg-1 was released using the modified BCR extraction. Some of the metals quantified were higher than the permissible levels, and the sludge not be used for soil enrichment. The results of this study demonstrated that the modified-BCR and the ultrasonic assisted-BCR extraction methods should be used in conjunction since one method alone might not be efficient in matrix breaking and releasing metal ions into solution. This may lead to incorrect conclusions about the presence or absence of metal ions in sewage sludge. Key words: Heavy metals, ultrasonication, sequential extraction, sludge, clarifier samples