Heavy Metals Bioconcentration from Soil to Vegetables and Assessment of Health Risk Caused by Their Ingestion

The present study was undertaken to assess the non-carcinogenic human health risk of heavy metals through the ingestion of locally grown and commonly used vegetables viz. Raphanus sativus (root vegetable), Daucus carota (root vegetable), Benincasa hispida (fruit vegetable) and Brassica campestris leaves (leafy vegetable) in a semi-urbanized area of Haryana state, India. Heavy metal quantification of soil and vegetable samples was done using flame atomic absorption spectrophotometer. Lead, cadmium and nickel concentration in vegetable samples varied in range of 0.12–6.54 mg kg^?1, 0.02–0.67 mg kg^?1 and <0.05–0.41 mg kg^?1, respectively. Cadmium and lead concentration in some vegetable samples exceeded maximum permissible limit given by World Health Organization/Food and Agriculture Organization and Indian standards. Much higher concentrations of Pb (40–190.5 mg kg^?1), Cd (0.56–9.85 mg kg^-1) and Ni (3.21–45.87 mg kg^?1) were reported in corresponding vegetable fields’ soils. Correlation analysis revealed the formation of three primary clusters, i.e. Cu–Cd, Cd–Pb and Ni–Zn in vegetable fields’ soils further supported by cluster analysis and principal component analysis. Bioconcentration factor revealed that heavy metals’ uptake was more by leafy vegetable than root and fruit vegetables. Hazard index of all the vegetables was less than unity; thus, the ingestion of these vegetables is unlikely to pose health risks to the target population.     

Human sex ratio at birth in South West Nigeria

BACKGROUND:

Human sex ratio at birth differs from one population to the other. This variation has been attributed to cultural practices, seasonal variation, small-family size policy and sex selective technology. Information on secondary sex ratio in Nigeria is limited.

AIMS AND OBJECTIVE:

To analyzed human sex ratio at birth for samples of the Nigerian population in 4 urban settings in Southwest Nigeria, in order to know the trend and to compare the findings with those of previous reports.

MATERIALS AND METHODS:

Data were collected from Obafemi Awolowo University (OAU) teaching hospital at Ile Ife and Wesley Guild hospital at Ilesa, Osun state; General hospital at Ogbomoso, Oyo state and Ekiti state specialist hospital at Ado-Ekiti, Ekiti state. The data consisted of 35 209 live single births recorded between 1995 and 2004. Each set of data was analyzed to determine the sex ratio by year, month and quarterly values. Chi-square analysis was used to determine the deviation of the sex ratios for the years from the average value.

RESULTS:

The annual average ratios of 104.7:100, 102.8:100, 98.9:100 and 100.8:100 were recorded for OAU teaching hospital, Wesley Guild Hospital, General Hospital and Ekiti State specialist hospital, respectively. When pooled together, the average ratio was 102.7:100. This shows some bias for male births. Data also indicates more male birth in the rainy season, suggesting a seasonal variation of sex ratio.

CONCLUSION:

These findings are representative of the populations in southwest Nigeria and are comparable to values obtained for other regions in Nigeria and other populations of African origin.     

Trace Metal Contents of Selected Seeds and Vegetables from Oil Producing Areas of Nigeria

The concentrations of accumulated trace metals in selected seeds and vegetables collected in the oil producing Rivers State of Nigeria were investigated. The values were compared with those of seeds and vegetables cultivated in Owerri, a less industrialized area in Nigeria. The lead (Pb) and cadmium (Cd) contents of the seeds obtained from Rivers State ranged between 0.10 and 0.23 μg/g dry weight, while those of the seeds cultivated in Owerri fell below the detection limit of 0.01 μg/g dry weight. The highest manganese (Mn) level (902 μg/g dry weight) was found in Irvingia garbonesis seeds cultivated in Rivers State. Similarly, the highest nickel (Ni) value (199 μg/g dry weight) was also obtained in I. garbonesis, however, in the seeds sampled in Owerri. The highest copper (Cu), zinc (Zn), and iron (Fe) levels (16.8, 5.27, and 26.2 μg/g dry weight, resp.) were detected in seeds collected in Rivers State. With the exception of Talinum triangulae, Ocinum gratissimum, and Piper guineese, with Pb levels of 0.09, 0.10, and 0.11 μg/g dry weight, respectively, the Pb and Cd levels in the vegetables grown in Owerri fell below the detection limit of 0.01 μg/g dry weight. The trace metal with the highest levels in all the vegetables studied was Mn, followed by Fe. The highest concentrations of Ni and Cu occurred in vegetables collected from Rivers State, while the highest level of Zn was observed in Piper guineese collected in Owerri, with a value of 21.4 μg/g dry weight. Although the trace metal concentrations of the seeds and vegetables collected in Rivers State tended to be higher than those of the seeds and vegetables grown in Owerri, the average levels of trace metals obtained in this study fell far below the WHO specifications for metals in foods.     

Concentrations and Distribution of Trace Metals in Water and Streambed Sediments of Orogodo River,Southern Nigeria

The distribution of Cd, Pb, Ni, Cr, Cu, Mn, Fe, and Zn in sediment and surface water, and some physico-chemical characteristics of Orogodo river sediments, were evaluated. The sediment pH ranged from 5.1–7.3; conductivity values ranged from 34.5 to 389.0 μScm^?1. Total nitrogen values ranged from 0.06–0.10%, NH₃-N values ranged from 0.25–0.44 mgkg^?1, percent total organic carbon ranged from 0.21–1.68%, and total phosphorus values ranged from 0.004–0.02% for dry and wet seasons. The sand fraction consists of 87–95%, silt fractions ranged from 0–2%, and clay fraction between 4–13%. The mean concentrations of metals (dry weight basis) in the streambed sediments ranged from 1.92–17.37 mgkg^?1 for Cu, 0.98–4.78 mgkg^?1 for Ni, 0.01–32.98 mgkg^?1 for Mn, 353.22–2045.64 mgkg^?1 for Fe, 69.96–100.16 mgkg^?1 for Zn, 0.21–1.32 mgkg^?1 for Cr, and Cd was less than 0.001 mgkg^?1 for wet and dry seasons. The mean concentrations of metals in the surface water ranged between 0.01–0.05–0.05 mg/L for Cu, nd-0.11 mg/L for Ni, 0.001–0.31 mg/L for Pb, 0.001–1.82 mg/L Mn, 0.01–3.52 mg/L for Fe, 0.16–0.61 mg/L for Zn, nd-0.007 mg/L for Cr, and <0.001 mg/L for Cd. Based on principal component analysis, two main sources of metals in the Orogodo River can be identified: (i) Cr, Cu, Pb, and Fe are mainly derived from industrial sources; (ii) Mn, Zn, and Ni associated with traffic activities. No element examined had a contamination/pollution index value greater than unity (pollution ranges). This implies that the multiple pollution indices obtained from the analysis showed that Orogodo River sediments were not polluted with heavy metals.     

叶菜类蔬菜不同部位的硝态氮累积对氮肥的响应

土壤盆栽油菜、小白菜和菠菜的叶柄对施氮的响应最为敏感。叶柄中硝态氮的累积量占整株蔬菜的一半以上（从54,9％到75．0％）。叶柄中硝态氮累积量与植物整株的硝态氮累积量呈极显著正相关。     

Availability,Cost, and Popularity of African Leafy Vegetables in Accra Markets,Ghana

Economic Botany - Consumption of African leafy vegetables can have a positive effect on nutrition, health, and economic well-being of both rural and urban populations. In this study, we undertook a...     

Assessment of Heavy Metals in Pharmacological Important Medicinal Plants Consumed in the Bannu District,Pakistan

This study assesses the contents of heavy metals in the four most commonly used indigenous medicinal plants in the Bannu District, Pakistan. The rapid appraisal approach was used along with semi-structured interviews with elderly people and herbalists for selection of indigenous plants. Heavy metals were determined via flame atomic absorption spectrometer by acid digestion of samples. Four medicinal plants were selected after interviews of 53 local residents and herbalists. Plant and soil samples were obtained for evaluations from a wastewater zone (WWZ) and a clean water zone (CWZ). Indigenous plants from the WWZ showed considerably higher metal contents compared to the CWZ. The trend of metals for indigenous medicinal plants grown in clean water was Mn > K > Na > Zn > Co > Fe > Cu while for wastewater the trend appeared as Co > K > Na > Zn > Fe > Mn > Cu. An alternative significant extent of research is needed to qualify the assessment of the human health insinuations of consumption of indigenous remedies. The heavy metal content of administering herbal medicine should be screened, as formulation and processing of medicine may affect heavy metal contents of the remedies.     

Levels of Some Trace Metals (Zn,Cr, and Ni) in the Muscle and Internal Organs of Cattle in Nigeria

ABSTRACT

This scoping study assessed the concentrations of zinc, chromium, and nickel in the muscle and internal organs of a sample of commercially available meat from Nigerian-bred cattle. The dried samples were digested with a 3:2 HNO₃/HClO₄ mixture and analyzed for these three metals with an atomic absorption spectrophotometer (AAS). The ranges of detectable values (mgkg^?1) were Zn (433.82–529.36) Cr (5.39–19.85), and Ni (0.80–1.72). Liver and muscle showed the highest concentrations of Zn while the highest concentrations of Cr occurred in the tripe. Nickel's concentration in the liver was the lowest. All samples showed Zn concentrations greater than the Codex Alimentarium limits of 50 mg/kg (muscle) and 80 mg/kg (edible offal), and 147 samples exceeded the 150 mg/kg limit set by the Australia New Zealand Food Authority. One hundred and twenty of the 150 samples showed Cd concentration above the U.S. Environmental Protection Agency's limit of 8 mg/kg, while 93% (muscle), 77% (liver), 97%(tripe), and 100% (kidney and intestine) showed concentrations of Ni higher than 0.5 mg/kg set as a guideline limit by Council of Mutual Economic Assistance. These high concentrations in the tested commercial sample of Nigerian beef may reflect the general pollution levels of these metals in the Nigerian environment.     

Analysis of Lead and Cadmium in Selected Leafy and Non-Leafy Edible Vegetables Using Atomic Absorption Spectrometry

Sixteen leafy and non-leafy edible vegetables were collected from the Northern Al-gour area, Jordan, and analyzed for Pb and Cd using atomic absorption spectrometry. In addition, soil samples were collected from areas adjacent to the sites from which the vegetables samples were collected and about 40 m from the road. Results indicated that the average Pb and Cd concentrations in the selected edible vegetables were found in the following order: Leaves > roots > fruits > seeds. Moreover, Pb and Cd levels in soil samples collected from the near main road were higher than those soil samples collected from the sites 40 meters far from the main road.     

Bioconcentration Factors and Trace Elements Bioaccumulation in Sporocarps of Fungi Collected from Quartzite Acidic Soils

The content of 19 metals (Al, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Cs, Ba, Ce, Pb, Th, U and Nd) was investigated in 15 edible species of phylum Basidiomycota collected in an area with quartzite acidic soils in a province of the central Spain. The study explores the differences in metal accumulation in relation to fungal species, and the results were related to metal content in soil through the determination of bioconcentration factors. Regarding the highest concentrations, Zn, Al, Cu and Rb were the metals more accumulated in the sporocarps. Notable concentrations were also found in Sr, Zr, Ba, Cs and Ce. The major bioconcentration factors were found for Cu and Zn in sporocarps of Agaricus silvicola and Lepista nuda. Regarding the different species, Tricholoma equestre and Cantharellus cibarius were those with the greatest capacity to absorb trace elements, and in contrast, Amanita caesarea and Agaricus campestris showed the lowest values. The cluster analysis shows that there are some species with the same nutritive physiology that share similarities in the absorptive behaviour. Lactarius sanguifluus and Lactarius deliciosus, both ectomycorrhizas of the genus Pinus, are closely related, and Clitocybe gibba, L. nuda and Marasmius oreades, all of them saprobes on soil organic matter, are very close too.     

Integrated assessment of the heavy metal pollution status and potential ecological risk in the Lagos Lagoon,South West,Nigeria

This study was carried out to assess the heavy metal pollution status and potential ecological risk in the Lagos lagoon, Nigeria. The concentrations of twelve heavy metals commonly associated with environmental pollution were determined in the sediments of the lagoon by Atomic Absorption Spectrophotometry (AAS) and the cold vapor method was employed for Mercury (Hg). Nonempirical risk indices and empirical Sediment Quality Guidelines (SQGs) were used to assess the ecological risk associated with heavy metal in the sediments. The nonempirical risk indices showed that Hg, Arsenic (As), and Cadmium (Cd) are the major contributors to the ecological risk associated with heavy metal pollution in the ecosystem. Comparison of heavy metal concentrations to the Screening Quick Reference Table (SQuiRT) showed that mean concentration of Cd (5.22 and 4.88 mg kg^?1 in dry and rainy seasons, respectively) exceeds the effect range low (ERL) value (1.20 mg kg^?1) in effect to biota. Industries sited around the lagoon have effluent output points in the lagoon serving as a major source of heavy metals coupled with indirect discharges from other sources. Heavy metals are nonbiodegradable, toxic and have the potential to alter ecosystem health, thus pollution sources should be effectively monitored and contained.     

The Function of Trace Metals in the Nitorgen Metabolism of Plants

In recent years trace metals have been found to be associatedwith flavo-proteins, a number of which are key enzymes in thenitrogen metabolism of plants. Thus Mo is a constituent of nitratereductase which mediates the reduction of nitrate to nitritein some bacteria, fungi, and higher plants. During the enzymicreduction of nitrate a one-electron change is involved, Mo⁶⁺Mo⁵⁺.Nitrite and hyponitrite reductases both require Fe and Cu andflavin for maximum activity and are inhibited by uncouplingreagents so that a phosphorylation takes place at these tworeductive steps. Hydroxylamine reductase, a flavoprotein thatis Mn-dependent, but, as with nitrate reductase, is unaffectedby uncoupling reagents. An aromatic route may also exist inplants for the reduction of organo-nitro compounds, but it ismore likely that the aliphatic route is the primary reductivepadiway. Mo, V, W, and Fe may all be involved in the process of N₂ fixationin free living micro-organisms and in the root nodule bacteria.The suggestion that the enzyme hydrogenase is coupled to N₂fixation is not borne out by the results of valency experimentswith Mo and V which show that an active hydrogenase does notnecessarily result in a vigorous fixation process. Although Mo has been shown to be a constituent of hydrogenasefrom Clostridium pasteurianum, experiments in this laboratoryshow that a deficiency of iron only reduced the enzyme in thisorganism and in Azotobacter. Both Mo and Fe, however, are essentialfor N₂ fixation. In some strains of Azotobacter, V or W canpartially replace Mo for N₂ fixation.     

Factors Controlling the Geochemical Partitioning of Trace Metals in Estuarine Sediments

The geochemical partitioning of trace metals in sediments is of great importance in risk assessment and remedial investigation. Selected factors that may control the partitioning behavior of Cu, Pb and Zn in non-sulfidic, estuarine sediments were examined with the use of combined sorption curve—sequential extraction analysis. This approach, which has not been previously used to examine estuarine sediments, allowed determination of sorption parameters for Cu, Pb and Zn partitioning to individual geochemical fractions. Partitioning behavior in sulfidic sediments was also determined by sequentially extracting Cu, Pb, and Zn from synthetic sulfide minerals and from natural sediment and pure quartz sand after spiking with acid-volatile sulfide (AVS). Trace metal sorption to the “carbonate” fraction (pH 5, NaOAc extraction) increased with metal loading due to saturation of sorption sites associated with the “Fe-oxide” (NH₂OH·HCl extraction) and “organic” (H₂O₂ extraction) fractions in non-sulfidic sediments. Freundlich parameters describing sorption to the “Fe-oxide” and “organic” fractions were controlled by the sediment Fe-oxide and organic carbon content, respectively. Sequential extraction of Cu from pure CuS, AVS-spiked sediment and AVS-spiked quartz sand showed that AVS-bound Cu was quantitatively recovered in association with the “organic” fraction. However, some AVS-bound Pb and Zn were recovered by the NH₂OH·HCl step (which has been previously interpreted as “Fe-oxide” bound metals) in the sequential extraction procedure used in this study. This indicates that the sequential extraction of Pb and Zn in sulfidic sediments may lead to AVS-bound metals being mistaken as Fe-oxide bound species. Caution should therefore be exercised when interpreting sequential extraction results for Pb and Zn in anoxic sediments.     

Concentration,Source, and Potential Human Health Risk of Heavy Metals in the Commonly Consumed Medicinal Plants

Biological Trace Element Research - A trend toward the use of traditional and herbal medicines has developed nowadays, and there is a growing concern regarding them being polluted with heavy...     

Changes in Trace Metals in Hemolymph of Baculovirus-Infected Noctuid Larvae

We studied how biologically relevant trace metals (i.e., micronutrients) in the hemolymph of larval Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae) changed in response to per os baculovirus infection, larval development, and injection of heat-killed bacteria. Concentrations of hemolymph Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, and Zn were measured using inductively coupled plasma-mass spectrometry. H. virescens larvae exhibited greater fluctuations in hemolymph trace metal levels in response to baculovirus infection and development than did H. zea larvae. H. zea single nucleopolyhedrosis virus infection significantly altered the levels of Cu, Fe, Mg, Mn, Mo, and Zn in fourth instar H. virescens larvae. Conversely, in fifth instar H. virescens and both H. zea instar infections, no metal levels were significantly different between infected and uninfected larvae. In fourth instar H. virescens hemolymph, Cu, Fe, Mo, and Zn increased during development. Cu, Fe, Mg, Mn, Mo, and Zn levels changed significantly during development in fifth instar H. virescens as well as both H. zea instars. Based on this analysis, metals were identified whose levels changed during development in both species and during the immune response of H. virescens larvae.     

Determination of Heavy Metals in Fish and Vegetables in Bangladesh and Health Implications

Concentrations of six heavy metals (chromium, nickel, copper, arsenic, cadmium, and lead) in fish and vegetables were estimated to evaluate contamination levels and health risks for Bangladeshi adults. The analyzed metals varied between different species of fish and vegetables. Metals like Ni, Cd, and Pb in fish species were higher than the respective maximum allowable concentrations (MAC), whereas As, Cd, and Pb in some species of vegetables exceeded the MAC. Health risks associated with these metal intakes were evaluated in terms of dietary intake and target hazard quotients (THQs). The THQ values for individual metals were below 1 (except As for some species), suggesting that people would not experience significant health hazards if they ingest a single metal from one species of fish and/or vegetable. However, total metal THQ (TTHQ) signifies the potential non-carcinogenic health hazard to the highly exposed consumers in Bangladesh. Also, the estimation showed that the carcinogenic risk (TR) of arsenic and lead were within the acceptable range for fish but exceeded the accepted risk level for vegetables. From the health point of view, this study showed that the inhabitants who consume contaminated fish and vegetables are exposed chronically to metal pollution with carcinogenic and non-carcinogenic consequences.     

Toxic Metals and Trace Elements in Artisanal Honeys from the Canary Islands

Honey is a natural product made by honey bees from the nectar of flowers or secretions produced by other living plant parts. The metal content of the honeys is related to the levels of metals in the environment. Due to the importance of honey in the human diet and the increase of environmental pollution, it is necessary to determine the content of metals in honey to evaluate the toxicological risk derived from its consumption. The objective of this study was to determine the content of 20 metals (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn) in different samples of artisanal honey from the Canary Islands (Spain) in order to evaluate the dietary intake derived from the consumption of these honeys. A total of 161 samples of different types of Canary honey were analyzed by ICP-OES (inductively coupled plasma–optical emission spectrometry). K (825 mg/kg) was the macroelement found in highest concentration, while B (4.25 mg/kg) was the trace element with the highest mean concentration. Al (3.33 mg/kg) was the most abundant toxic metal, followed by Pb (0.040 mg/kg) and Cd (0.002 mg/kg). A mean consumption of 25 g/day of honey mainly contributes to the recommended daily intake of Cu (1.34% adults) and K (0.67% adults). As regards the toxic metals, the contribution percentage to the TDI (tolerable daily intake) of Pb at 2.92% for adults is noteworthy. However, the consumption of honey does not imply a high intake of metals and, therefore, does pose a risk to the health of adult men and women.

     

Land crisis on the Mambila Plateau of Nigeria, West Africa

The Mambila plateau in Nigeria features unique physical and climatic conditions for human settlement as for cattle breeding: it is within such an environment that the Mambila farmers have settled and developed as a dense population. During the 19th century the highlands became the main sources of slaves for the Muslim Fulani kingdoms of Banyo and Gashaka. Although resisting strongly, the Mambila villages fell one after the other. This resulted in a demographic collapse: by 1930 the Mambila were reduced to a population of 16,000. In the 1920s Mbororo and Fulani graziers began to settle in the region: their livestock became the main cause of environmental degradation. Severe erosion of the grazed land can now be observed, mainly characterized by the deepening of the river beds and the collapse of river banks. Such a phenomenon is attributed to a change in the rainwater flows due to the exhaustion of the vegetation cover. The uncontrolled growth of livestock has been followed by high competition for land between the graziers and those Mambila farmers who survived the Fulani occupation. The graziers holding most of the political power have progressively deprived the farmers of their lands: the latter are now confined within isolated small enclaves. They have lost their economic independence and are reduced to work for the graziers or to emigrate to Cameroon. Furthermore, in a large part of the Mambila plateau, the pastoral range has been divided between the graziers, excluding the Mambila farmers, as well as the poorest Fulani, from land ownership and enhancing their dependency on the graziers. Such an explosive situation is illustrated by two surveys of the Kuma and Leme regions. Over the 78 km² studied in Kuma, the Mambila possess only 22% of the area; the survey found 132 herds (at an estimated total of 9475 cattle) with a population density of 1.5 cattle per ha, almost totally owned by Muslim graziers. The area studied in Leme covers 113.5 km² of uneven land. Although confined to nine enclaves, the Mambila owned 32% of the land, while the Muslim graziers possess 67%. 145 herds have been counted (at an estimate total of 10,215 cattle): 63% are owned by the Mbororo, 20% by Fulani and the Haoussa from Gembu, 10% by the Mambila, and 7% by the recent Yamba migrants.