Derivation and validation of thresholds of cadmium, chromium, lead, mercury and arsenic for safe rice production in paddy soil.

Cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg) and arsenic (As) are potent toxicants to human health via dietary intake. It is imperative to establish accurate soil thresholds based on soil-plant transfer models and food safety standards for safe agricultural production. This study takes rice genotypes and soil properties into account to derive soil thresholds for five heavy metal(loid)s using the bioconcentration factors (BCF) and species sensitivity distribution (SSD) based on the food safety standard. The BCF generated from two paddy soils was calculated to investigate the sensitivity of heavy metal accumulation in nine rice cultivars in a greenhouse pot experiment. Then, empirical soil-plant transfer models were developed from a middle-sensitivity rice cultivar (Denong 2000, one selected from nine rice) grown in nineteen paddy soils with various soil properties under a proper exogenously metal(loid)s concentration gradient. After normalization, hazardous concentrations from the fifth percentile (HC5) were calculated from the SSD curves, and the derived soil thresholds were obtained from HC5 prediction models that based on the combination of pH and organic carbon (OC) or cation exchange capacity (CEC). The soil Cd threshold derived based on pH and organic carbon (pH < 7.5, OC ≥ 20 g kg-1) was 1.3-fold of those only considering pH, whereas the Pb threshold (pH > 6, CEC ≥ 20 cmolc kg-1) was 3.1 times lower than the current threshold. The derived thresholds for five elements were validated to be reliable through literature data and field experiments. The results suggested that deriving soil heavy metal(loid)s threshold using SSD method and local food safety standards is feasible and also applicable to other crops as well as other regions with potential health risks of toxic elements contamination in agricultural production.

Temporal variability of blood lead, mercury, and cadmium levels in elderly panel study (2008-2014).

BACKGROUND: Biological measurements have been employed as useful biomarkers for exposure. Because of its property of reflecting toxicokinetic differences, however, within-subject variability leads to biased results in epidemiologic studies. METHOD: We examined the variability of lead (Pb), mercury (Hg), and cadmium (Cd) levels in blood samples from 1429 participants among 1677 elderly individuals aged over 60 years who lived in an urban area from August 2008 to April 2015. RESULTS: The geometric means of blood Pb, Hg, Cd were 1.92µg/dL, 2.48µg/L, and 1.33µg/L, and the intra-class correlations (ICCs) were 0.81, 0.71, and 0.83, respectively. The mean values of Pb and Hg levels in this study were lower than the results from single spot samples in other national biomonitoring surveys in Korea, with the exception of Cd was higher than those in other studies. Moreover, the predicted exceedances over the guidance levels for Pb, Hg, and Cd were 1.9%, 4.2%, and 0.3%, respectively. CONCLUSION: Korean elderly were exposed to high levels of Pb, Hg and Cd. Especially, those who had high levels of Cd were continuously exposed to Cd during study period with the 6 collection intervals. Therefore, factors affecting environmental Cd exposure should be further studied in the future.

Associated factors for higher lead and cadmium blood levels, and reference values derived from general population of São Paulo, Brazil.

Human activities are associated with emissions of various metals into the environment, among which the heavy metals lead and cadmium stand out, as they pose a risk to human life even at low concentrations. Thus, accurate knowledge of the levels of these metals exhibited by the overall population, including children, is important. The aim of this study was to estimate the concentrations of lead and cadmium in the blood of adults, adolescents and children residing in the city of São Paulo, assess factors associated with higher lead and cadmium blood levels, and to establish reference values for this population. The study sample consisted of 669 adults over 20 years old, 264 adolescents aged 12 to 19 years old and 391 children under 11 years old from both genders. The samples were collected at the end of 2007 and during 2008 in different city zones. Higher blood lead concentration was significantly associated with gender, smoking, offal intake, area of residence and age. The blood cadmium concentration was significantly associated with gender, smoking, consumption of distilled beverages and age. The reference values of lead and cadmium established for adults above 20 years old were 33 µg/L and 0.6 µg/L, respectively, for adolescents (12 to 19 years old) were 31 µg/L and 0.6 µg/L, respectively and for children under 11 years old were 29 µg/L and 0.2 µg/L, respectively. The results of this study indicate that the exposure levels of the investigated population to lead and cadmium are low.

Content of Cadmium and Lead in Vegetables and Fruits Grown in the Campania Region of Italy.

Illegal practices of waste combustion and their burial in some land devoted to agricultural crops caused a severe economic crisis of the agriculture and food sector in the Campania region of Italy. To assess the levels of contamination by lead and cadmium, the only metals subject to European Union legislation, a system of monitoring of plant foods in the whole territory of the region has been promoted, with the goal of certifying productions and consumer protection. In fact, products that comply with European Union standards are assigned a Quick Response Code, which guarantees the traceability of the product (manufacturer and location). The code also ensures the safety of the product, as it allows the consumer to see the results of the analysis performed on the specific chain of production. The content of lead and cadmium was determined in 750 vegetable samples by using the atomic absorption spectrophotometry after microwave mineralization. These levels were below the maximum limits in all but three samples; two samples of tomatoes exceeded the maximum level of cadmium, and one sample of valerian contained an excess of lead.

The heavy metals cadmium, lead and mercury in raw materials of animal origin: evaluation of data from practice.

Raw materials from animal origin are widely used in homoeopathy. Due to the lack of dedicated limits, the quality requirements for herbal drugs of the European Pharmacopoeia (Ph. Eur.) and/or the German Homoeopathic Pharmacopoeia (Homöopathisches Arzneibuch, HAB), including limits for heavy metals such as cadmium, lead and mercury, have been applied. A recent database evaluation shows that for some raw materials of animal origin the Ph. Eur. limits for herbal drugs cannot be met in practice. For this reason proposals for new limits for cadmium, lead and mercury are made based on recent experiences from the companies' daily practice. These specific limits are suggested to be included in the individual monographs of the Ph. Eur. or at least the German HAB, respectively, for Ambra grisea, Euspongia officinalis, Formica rufa and Sepia officinalis.

A baseline study of levels of mercury, arsenic, cadmium and lead in Northeast Arctic cod (Gadus morhua) from different parts of the Barents Sea.

This study is one of several baseline studies that will provide basic and reliable information about the content of undesirable substances in important species of fish caught in Norwegian waters. Concentrations of metals in the muscle and liver of more than 800 Northeast Arctic cod caught at 32 sites in the Barents Sea are reported. The highest concentration of both mercury in the muscle and cadmium in the liver was found in cod caught in the western part of the Barents Sea, while the highest concentration of total arsenic was found in cod from the eastern part. The arsenic concentrations varied greatly among individual fish, ranging from 0.3 to 170 mg kg(-1) wet weight in the muscle. Such high levels of total arsenic have never previously been reported in any fish, and the primary factor for these high concentrations is likely to be the shrimp in the cod diet.

Determination of lead and cadmium concentration limits in agricultural soil and municipal solid waste compost through an approach of zero tolerance to food contamination.

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4-150 mg/kg and Cd at 0.02-20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C(ul)) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers' fields. Lead and Cd concentration limits in soil were calculated by dividing C(ul) with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.

Determinación y estandarización de plomo en sangre en operarios de estaciones de servicio del Estado Mérida / Blood lead determination and standardization in petrol station workers in the State of Merida

En este trabajo se ha determinado el contenido de plomo (Pb) en sangre en operarios de estaciones de servicio de la ciudad de Mérida (Venezuela) y en un grupo de personas no expuestas ocupacionalmente. Las muestras de sangre provenientes de sujetos de ambos sexos n=21 (controles) y n=65 (personal expuesto) fueron procesadas por absorción atómica con atomización electrotérmica (ETAAS). Las concentraciones obtenidas de 15,27±9,62 y 83,74±28,95 µg/L para los grupos denominados como control y expuesto respectivamente, muestran diferencias altamente significativas que evidencian una exposición directa al Pb, por cuanto los valores del grupo expuesto ocupacional son más de 5 veces superiores a los del grupo control. Los resultados obtenidos también muestran que valores iguales o superiores a 54,79 µg/L son indicadores de exposición directa al Pb, permitiendo establecer valores de tolerancia entre los intervalos de 24,89 y 112,69 µg/L. Estos valores de referencia se encuentran por debajo de lo descripto por Burguera y cols. (1997), lo cual podría atribuirse al reemplazo gradual de la gasolina con plomo, en los últimos años, que ha llevado a una disminución de un 27% en los niveles de plomo en sangre, en comparación con un estudio similar realizado en esta misma ciudad en el año 1997.

In this work the lead (Pb) content in blood was determined in petrol station workers in the city of Merida-Venezuela and in a group of people not occupationally exposed. The blood samples coming from subjects of both sexes n=21 controls and n=65 exposed workers were processed by atomic absorption with electrothermal atomization (ETAAS). The 15.27±9.62 and 83.74±28.95 µg/L concentrations obtained for the group referred to as control and exposed respectively show highly significant differences that evidence a direct exposure to Pb, since the values of the occupationally exposed group are more than 5 times higher than those of the control group. The results obtained also show that values equal to or higher than 54.79 µg/L are indicative of direct exposure to Pb, making it possible to establish tolerance values between the 24.89 and 112.69 µg/L intervals. These reference values are below what was reported by Burguera et al (1997) which could be attributed to the gradual substitution of gasoline for lead that has originated a 27% decrease in lead levels in blood, if compared with a similar study carried out in the same city in 1997.

[Determination of trace lead and iron in nickel chloride and manganese sulfate by flame atomic absorption spectrometry after coprecipitation with yttrium phosphate].

Using yttrium phosphate as the coprecipitation collector for the separation and preconcentration of trace lead and iron in nickel chloride and manganese sulfate, flame atomic absorption spectrometric (FAAS) determination was described in the present paper. Coprecipitation parameters including the pH of the solution, and the amounts of YCl3 and H3 PO4 were discussed. It was found that lead and iron in nickel chloride could be coprecipitated quantitatively in the range of pH 3.0-4.0, and so could be lead in manganese sulfate. The detection limits (3sigma) of lead and iron in 20 mL solution were 1.63 x 10(-2) mg x L(-1) and 4.58 x 10(-2) mg x L(-1) respectively. In NiCl2 solution the standard addition recoveries for lead and iron were 100.91% and 99.73% respectively, and in MnSO4 solution the standard addition recoveries were 99.45% and 98.98% respectively. The method has eliminated the interference of matrix, and the result is satisfied.

Multielement determination of cadmium and lead in urine by simultaneous electrothermal atomic absorption spectrometry with an end-capped graphite tube.

A method for the multielement determination of cadmium and lead in urine is proposed by simultaneous electrothermal atomic absorption spectrometry (SIMAAS) with an end-capped transversely heated graphite atomizer (EC-THGA). The best conditions for cadmium and lead determination were obtained in the presence of NH4H2PO4 as a chemical modifier, using 500 degrees C and 1800 degrees C as the pyrolysis and atomization temperatures, respectively. Urine samples were diluted 1 + 4 directly in autosampler cups with a mixture of 0.125% (w/v) Triton X-100 + 2.5% (v/v) HNO3 + 0.31% (w/v) NH4H2PO4. The optimized heating program was carried out in 57 s, and the instrument calibration was done with aqueous reference solutions. The use of EC-THGA increased the sensitivity of cadmium and lead by 14% and 25%, respectively. The detection limits (n = 20, 3delta) were 0.03 microg L(-1) (0.36 pg) for cadmium and 0.57 microg L(-1) (6.8 pg) for lead. The performance of EC-THGA was acceptable up to 500 heating cycles. The reliability of the entire procedure was checked with the analysis of a lyophilized urine certified reference material. The found concentrations were in agreement with the recommended values (95% confidence level).

Inspection of lead aprons: criteria for rejection.

Lead aprons utilized by personnel performing fluoroscopy are routinely inspected for damage to comply with the requirements of hospital accrediting organizations. Fluoroscopic or radiographic examination of lead aprons may reveal imperfections ranging from small pinholes to large tears. Currently, there are no standards establishing a criteria for acceptance or rejection of lead aprons. As a consequence, many facilities have established arbitrary rejection criteria. Often lead aprons are discarded due to small imperfections, a practice that can become costly to these institutions. We have calculated increases in doses to the whole body for varying sizes of holes, including special consideration of the effects on effective dose equivalent when the hole is over the testes and thyroid. ALARA standards for cost per personsievert averted are used to establish a rational basis for criteria of acceptance or rejection of lead aprons.

Isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS) for the certification of lead and cadmium in environmental standard reference materials.

Lead (Pb) and cadmium (Cd) have been determined in six new environmental standard reference materials (SRMs) using isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS). The SRMs are the following: SRM 1944, New York-New Jersey Waterway Sediment, SRMs 2583 and 2584, Trace Elements in Indoor Dust, Nominal 90 mg/kg and 10,000 mg/kg Lead, respectively, SRMs 2586 and 2587, Trace Elements in Soil Containing Lead from Paint, Nominal 500 mg/kg and 3,000 mg/kg Lead, respectively, and SRM 2782, Industrial Sludge. The capabilities of ID ICP-MS for the certification of Pb and Cd in these materials are assessed. Sample preparation and ratio measurement uncertainties have been evaluated. Reproducibility and accuracy of the established procedures are demonstrated by determination of gravimetrically prepared primary standard solutions and by comparison with isotope dilution thermal ionization mass spectrometry (ID TIMS). Material heterogeneity was readily demonstrated to be the dominant source of uncertainty in the certified values.

National Institute for Occupational Safety and Health; occupational exposure to inorganic lead: request for comments and information; republication--NIOSH. Request for comments and information relevant to occupational exposure to inorganic lead.

NIOSH is reviewing its recommendations contained in the document Criteria for a Recommended Standard.... Occupational Exposure to Inorganic Lead, Revised Criteria--1978 [NIOSH 1978]. The evaluation of recent literature indicates that the NIOSH recommended exposure limit [REL] of 100 micrograms/m3 as an 8-hour time-weighted average [TWA] in that document does not sufficiently protect workers from the adverse effects of exposure to inorganic lead. NIOSH is requesting comments and information relevant to the evaluation of the potential health risks associated with occupational exposure to inorganic lead, as well as case reports or other data that demonstrate adverse health effects in workers exposed to inorganic lead at or below the OSHA permissible exposure limit [PEL] of 50 micrograms/m3 as an 8-hour TWA and any information pertinent to evaluating the technical feasibility of establishing a more protective REL for inorganic lead. NIOSH is also soliciting information on worker blood lead levels [BLLs] including data on methodologies used in measuring BLLs in the workplace and information that can be used for comparing airborne inorganic lead concentrations to observed BLLs. NIOSH intends to analyze the feasibility of developing preventive measures including an REL that would provide better protection for workers. In the interim, NIOSH plans to adopt the more protective current OSHA PEL as its REL.

Determination of cadmium and lead levels in human blood of a general Czech population by GFAAS.

The development of a method for the direct determination of cadmium (Cd) and lead (Pb) in blood samples by GFAAS, is described. Samples were properly diluted by a matrix modifier to enable measuring both analytes in one solution. For the determination of Cd, a matrix-matched, and for the determination of Pb, an aqueous calibration was used. The precision, accuracy, and detection limits of this method are presented. A method is applied to the investigation, of Cd and Pb levels in a general Czech population, selected according to the WHO-MONICA project criteria. To avoid possible contaminations, samples were treated in a clean room class 100.

[Cadmium and lead levels in milk, milk-cereal and cereal formulas for infants and children up to 3 years of age]. / Wystepowanie kadmu i olowiu w odzywkach mlecznych, mleczno-zbozowych i zbozowych przeznaczonych dla niemowlat i dzieci do lat 3.

Cd and Pb contents were determined in milk formulae, milk-cereal formulae and cereal formulae produced by Okregowe Zaklady Koncentratów Spozywczych (OZKS) (Regional Food Concentrates Processing Plants) for infants and children up to 3 years of age. The major parts of the assortments were found to contain products whose cadmium and/or lead contents exceeded the admissible norms. These contents were as follows: in milk formulae: from less than 2 to 8 micrograms Cd/kg and from less than 20 to 180 micrograms Pb/kg; in milk-cereal formulae: from less than 2 to 20 micrograms Cd/kg and from less than 20 to 180 micrograms Pb/kg; in cereal formulae from less than 2 to 70 micrograms Cd/kg and from less than 20 to 400 micrograms Pb/kg. Contents of Cd and Pb were the highest in cereal formulae mainly in those produced of wheat flour and buckwheat-rice flour. Determinations of Cd and Pb contents in raw materials and in some cereal intermediate products revealed that the occurrence of excessively high Cd and Pb contents in the cereal-containing formulae was due to contamination of the cereal raw materials with these metals.

[Evaluation of cadmium, mercury and lead intake with daily food rations]. / Ocena pobrania kadmu, rteci i olowiu z calodziennymi odtworzonymi racjami pokarmowymi.

Using the data of the Central Statistical Bureau concerning the consumption of about 90 basic food products daily food rations were reproduced as taken by medium-income worker families. The diets were reproduced in Lublin, Olsztyn, Poznan, Warsaw and Wroclaw determining in them cadmium, mercury and lead by atomic absorption spectrophometry. It was found that weekly intake of cadmium with food rations was in the range from 133 to 189 mcg, that of lead was 504 to 952 mcg, and mercury from 61.6 to 154.0 mcg. The obtained results were not exceeding 50% PTWI for any of these metals but they were rather higher than those in previous years, which indicates increasing contamination of food products with toxic elements. In areas with higher industrialization level the dietary intake of metals was as a rule higher than in areas with lower accumulation of industry.