Elements in rice from the Swedish market: 1. Cadmium,lead and arsenic (total and inorganic)

A survey of the levels of cadmium, lead and arsenic in different types of rice available on the Swedish retail market was carried out in 2001–03. The types of rice included long and short grain, brown, white, and parboiled white rice. The mean levels found were as follows: total As: 0.20 mg kg^?1, inorganic As: 0.11 mg kg^?1; Cd: 0.024 mg kg^?1; and Pb: 0.004 mg kg^?1. ICP-MS was used for the determination of As (total and inorganic) after acid digestion. Lead and cadmium were determined using graphite furnace atomic absorption spectrometry (GFAAS) after dry ashing. In countries where rice is a staple food, it may represent a significant contribution in relation to the provisional tolerable weekly intake for Cd and inorganic As.     

Contribution of water and cooked rice to an estimation of the dietary intake of inorganic arsenic in a rural village of West Bengal, India

Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50, 250 or 500 µg l^-1). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642 µg kg^-1. The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000 µg day^-1 for initial arsenic concentrations in the cooking water of 50, 250 and 500 µg arsenic l^-1, respectively, compared with the tolerable daily intake which is 150 µg day^-1.     

Trace metals in soft and durum wheat from Italy

A survey was carried out with the aim to assess the levels of some toxic (cadmium, lead) and essential (copper, zinc) trace metals in wheat grown in Italy. A total of 178 samples of soft wheat grain and 239 samples of durum wheat grain from all the Italian wheat-growing regions were pooled into 35 and 38 representative samples respectively. After dry ashing, cadmium and lead were determined by graphite furnace atomic absorption spectrometry (GFAAS), whereas copper and zinc were determined by flame atomic absorption spectrometry (FAAS). In soft wheat the mean and median contents of all samples were (on a dry weight basis) 40 and 33 mu g kg^-1 for cadmium, 16 and 14 mu g kg^-1 for lead, 3.4 and 3.2 mg kg^-1 for copper, 33 and 32 mg kg^-1 for zinc. Similar levels were found in durum wheat. In this latter case the mean and median were 42 and 39 mu g kg^-1 for cadmium, 15 and 14 mu g kg^-1 for lead, 3.5 and 3.2 mg kg^-1 for copper, 34 and 34 mg kg^-1 for zinc. Significant differences were detected for some metals in relation to geographical provenance and variety. The average intake of the four selected elements from wheat-based products was estimated for the Italian population.     

Multi-element survey of allotment produce and soil in the UK

In 2004, a survey of 12 metals was carried out in six rural and six urban allotment sites across the UK. A total of 215 samples of vegetables and 36 samples of soft fruit were analysed using ICP-MS, and 51 samples of soil using ICP-OES. On a fresh weight basis, Cu levels in produce ranged 0.119-2.271 mg kg^-1. The highest levels measured (in mg kg^-1) were Pb 0.164 in a sample of blackcurrants, Cd 0.039 in spinach, Hg 0.003 in curly kale and As 0.025 in raspberries. The lowest concentrations for these metals were below the level of detection (LOD) in numerous samples. The majority of Pt samples were below LOD and all were under the limit of quantification (LOQ). The results of the survey showed that the concentrations of the metals in vegetables, fruit and soils were consistent with previous studies and, generally, at low levels.     

Lead and cadmium in meat and meat products consumed by the population in Tenerife Island, Spain

The aim of this study was to determine the levels of lead and cadmium in chicken, pork, beef, lamb and turkey samples (both meat and meat products), collected in the island of Tenerife (Spain). Lead and cadmium were measured by graphite furnace atomic absorption spectrometry (GFAAS). Mean concentrations of lead and cadmium were 6.94 and 1.68 µg kg^-1 in chicken meat, 5.00 and 5.49 µg kg^-1 in pork meat, 1.91 and 1.90 µg kg^-1 in beef meat and 1.35 and 1.22 µg kg^-1 in lamb meat samples, respectively. Lead was below the detection limit in turkey samples and mean cadmium concentration was 5.49 µg kg^-1. Mean concentrations of lead and cadmium in chicken meat product samples were 3.16 and 4.15 µg kg^-1, 4.89 and 6.50 µg kg^-1 in pork meat product, 6.72 and 4.76 µg kg^-1 in beef meat product and 9.12 and 5.98 µg kg^-1 in turkey meat product samples, respectively. The percentage contribution of the two considered metals to provisional tolerable weekly intake (PTWI) was calculated for meat and meat products. Statistically significant differences were found for lead content in meats between the chicken and pork groups and the turkey and beef groups, whereas for cadmium concentrations in meats, significant differences were observed between the turkey and chicken, beef and lamb groups. In meat products, no clear differences were observed for lead and cadmium between the various groups.     

Levels of eight trace elements in edible mushrooms from a rural area

Eight trace elements were determined using ICP-MS in 78 fruiting body samples of 22 edible mushroom species. The mushrooms were collected from four sites in a rural area, unpolluted by human activity. Median values (dry matter) were as follows: Arsenic (As) 1.45 mg kg^-1, barium (Ba) 1.41 mg kg^-1, cobalt (Co) 0.28 mg kg^-1, copper (Cu) 47.0 mg kg^-1, rubidium (Rb) 130 mg kg^-1, silver (Ag) 2.95 mg kg^-1, thallium (Tl) 0.02 mg kg^-1 and vanadium (V) 0.25 mg kg^-1. Higher trace element accumulation was observed in samples of Macrolepiota procera, Macrolepiota rhacodes, Lycoperdon perlatum, Lycoperdon gigantea and Xerocomus chrysenteron for As and Cu, and in samples of Cantharellus cibarius and of genera Boletus and Suillus for Rb.     

Toxic and essential metals in liver, kidney and muscle of pigs at slaughter in Galicia, north-west Spain

The aims of the study were to evaluate toxic and essential metal concentrations in meat and offal from pigs in north-west Spain to compare these with reported metal concentrations in pigs in other countries and in cattle in this region, and to relate the observed concentrations to maximum acceptable concentrations. Samples from 63 pigs aged 6 months were randomly collected at slaughter. After acid digestion, levels of metals were determined by ICP-OES and ICP-MS. As regards the toxic metals, mean concentrations in liver, kidney and muscle were 0.073, 0.308 and 0.009 mg kg^-1 fresh weight for cadmium, 0.004, 0.008 and 0.003 mg kg^-1 for lead, 0.013, 0.011 and 0.003 mg kg^-1 for arsenic, and 0.001, 0.002 and 0.001 mg kg^-1 for mercury. These concentrations can be considered low, and in general similar to those reported in similar studies in recent years. In addition, maximum admissible concentrations established by the European Union were not exceeded in any sample. As regards the essential metals, concentrations in liver, kidney and muscle were 14.9, 5.63 and 6.85 mg kg^-1 for copper, 81.3, 28.9 and 42.5 mg kg^-1 for zinc, 195, 51.6 and 26.5 mg kg^-1 for iron; 1.17, 2.51 and 0.656 mg kg^-1 for selenium, 3.32, 1.56 and 1.01 mg kg^-1 for manganese, 0.023, 0.027 and 0.003 mg kg^-1 for cobalt, 0.120, 0.077 and 0.131 mg kg^-1 for chromium, 0.009, 0.027 and 0.026 mg kg^-1 for nickel, and 1.62, 0.683 and 0.140 mg kg^-1 for molybdenum. These concentrations are all within the accepted adequate-safe ranges for this animal species, and in general are in line with those previously reported in the literature.     

Persistent organochlorine pesticides in Mexican butter

Organochlorine pesticides have been used in Mexico in malaria control programmes against ectoparasites and as seed dresser. Owing to their chemical stability, they tend to accumulate in the lipid part of the organisms. The stored pesticides are excreted with the endogenous fat during milk production. The aim was to monitor the organochlorine pesticide levels in butter manufactured in Mexico. From the pesticides, only HCB, β-HCH, pp '-DDT, op '-DDT and pp '-DDE with major frequency and levels were detected. The HCB mean level was low at 0.008 mg kg -1 on a fat basis. From the HCH isomer, only the β-HCH at 0.065 mg kg^-1 on a fat basis was determined, remaining as the main contaminant of the monitored butters. Among DDTs, pp '-DDE was the major constituent (0.043 mg kg^-1 on a fat basis) followed by pp '-DDT (0.036 mg kg^-1) and op '-DDT (0.009 mg kg^-1). Comparing the previous study (1994) and this one (2001), all organochlorine pesticides had a descendent tendency; β-HCH decreased from 0.095 to 0.065 mg kg^-1 on a fat basis, whereas the total DDT decreased from 0.056 to 0.047 mg kg^-1, pp '-DDT from 0.050 to 0.036 mg kg^-1, op '-DDT from 0.018 to 0.009 mg kg^-1, while pp '-DDE increased from 0.032 to 0.043 mg kg^-1. The decreased DDT levels in Mexican butters is caused by the substitution of organochlorine insecticides with pyrethroids used by the Mexican Ministry of Health since 1999 in sanitary programmes.     

Determination of cadmium, chromium, lead and vanadium in six fish species from the Adriatic Sea

Concentrations of cadmium, chromium, lead and vanadium were determined in samples of six fish species collected along the coast of the Adriatic Sea. The concentrations of the elements studied were generally low, often below the detection limits of the analytical methods. The highest values (μg kg^-1 fresh weight) were observed, mainly in the central area of the Adriatic Sea, for anchovy (Cd 20.2, Cr 82.9, Pb 45.9, V 89.9), red mullet (Cd 3.1, Cr 31.0, Pb 36.0, V 79.1) and mackerel (Cd 7.7, Cr 28.0, Pb 11.4, V 43.5). The concentrations of cadmium and lead in all the species examined were below the maximum levels indicated by the European Community for these two elements in seafood, and also would lead to exposure levels lower than the provisional tolerable daily intakes suggested by the FAO/WHO for Cd (420 μg week^-1 for a 60-kg person) and Pb (1500 μg week^-1 for a 60-kg person). The concentration of chromium was lower than the recommended daily amount (50-200 μg day^-1 for a 60-kg person) indicated by the US National Research Council. An 11-34% contribution to the daily vanadium ingestion with fish was calculated for the population of the Adriatic coast.     

Determination of polydimethylsiloxanes by 1H-NMR in wine and edible oils

Fourier transform ¹H-nuclear magnetic resonance (NMR) spectroscopy was suitable for the quantitative determination of polydimethylsiloxanes (PDMS) in wine and edible oil samples. This approach offers highly specific qualitative and quantitative analysis due to silicone-specific location of proton signals linked to carbon atoms located directly next to silicon atoms (0-0.5 ppm), as well as a different location of signals in the range for different organosilicon structures. The method can be used for the control of PDMS at regulatory limits in foodstuffs (10 mg kg^-1) using hexamethyldisiloxane (HDMS) as an internal standard. Samples were prepared by extraction under suitable conditions to separate the analyte, and with analyte enrichment before ¹H-NMR analysis. Analytical procedures were developed to permit the determination of PDMS at 0.06 mg kg^-1 in wine and at 6 mg kg^-1 in edible oils samples using readily available NMR instrumentation. It was, however, possible to lower the limit of detection to 6 μg kg^-1 for wine and to 60 μg kg^-1 for edible oils using a higher field instrument (500 MHz). Relative standard deviations (S_r) were obtained for wine (0.028) and for oil samples (0.043), which when compared with values obtained for samples spiked with PDMS (0.021) indicated that the sample preparation was the main factor determining the precision of the method. The average recovery rates for PDMS were 97 and 95% for wine and edible oils, respectively. PDMS was detected in four brands of Italian wine, with Chianti-Rafaello containing the highest concentration (0.35 mg kg^-1), and in four types of edible oils, highest concentration (11.9 mg kg^-1) being found in Italian corn oil. None of the levels of PDMS found in the food samples exceeded the permissible standards laid down by the Codex Alimentarius Commission (10 mg kg^-1), with the exception of the one corn oil sample.     

Acrylamide in Asian foods in Hong Kong

About 400 food samples, mainly Asian foods available in Hong Kong, were tested for acrylamide by an LC-MS/MS method using [1, 2, 3-¹³C₃]-acrylamide as surrogate. The acrylamide levels in the more commonly consumed food items in the food groups such as rice and rice products, noodles, bakery and batter-based products, were generally less than 60 μg kg^-1. Higher levels were found in the food groups such as biscuit-related products and crisps. The highest levels were detected in potato crisps (1500-1700 μg kg^-1). Lower levels were found in rye flour-based crisps (440 μg kg^-1), followed by corn-based (65 to 230 μg kg^-1) and wheat flour-based crisps (61-200 μg kg^-1), and then rice flour-based crisps (15-42 μg kg^-1). The acrylamide formation during deep frying of a wheat flour-based product, Chinese fried fritter, was studied. Deep-frying at 170°C resulted in gentle but steady rise in acrylamide content. A steep rise for frying at 210°C was recorded. The moisture content of the product decreased with frying time, but the fat content increased. It is proposed that the reaction for the formation of acrylamide was initiated on the surface and then penetrated into the interior of the food matrix by heat transfer via radiation/conduction and diffusion of hot oil.     

Methylmercury determination in fish and seafood products and estimated daily intake for the Spanish population

The mercury content of 25 samples of fish and seafood products most frequently consumed in Spain was determined. A simple method comprising cold vapour and atomic absorption spectrometry was used to determine separately inorganic and organic mercury. In all samples inorganic mercury content was below 50 µg kg^-1. There was wide variability, among not only the mercury levels of different fish species, but also for different samples of the same species — with the methylmercury content ranging from below 54 to 662 µg kg^-1. The highest mean methylmercury content was found in fresh tuna. Based on an average total fish consumption of 363 g/person week^-1, the methylmercury intake was estimated to be 46.2 µg/person week^-1. Therefore, the mercury intake of Spanish people with a body weight ≤ 60 kg is lower than the Joint FAO/WHO Expert Committee on Food Additives (JECFA) provisional tolerable weekly intake (PTWI) of 1.6 µg kg^-1 body weight, but exceeds the US National Research Council (NRC) limit of 0.7 µg kg^-1 body weight week^-1 based on a benchmark dose.     

Study on the effect of grain storage and processing on deltamethrin residues in post-harvest treated wheat with regard to baby-food safety requirements

The effects of storage intervals and of milling procedures on dissipation of deltamethrin residues in post-harvest treated wheat grain were studied with the aim to obtain scientific data on compliance of the processed products with the safety requirements concerning baby foods. The insecticide formulation was applied on stored wheat at a recommended rate of active ingredient of 0.5 mg kg^-1 and at a higher rate of 4 mg kg^-1, performing the highest protective effect. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Eight fractions—bran, semolina, three types of groats, and three types of flour—were collected after milling of grain and analysed for determination of pesticide residues. The residues were determined by gas chromatography characterized by the limit of determination of 0.005 mg kg^-1, low enough for enforcement of the maximum residue level of 0.01 mg kg^-1 established by the European Commission Directive for any pesticide in cereal-based foods. Deltamethrin applied post-harvest on wheat as grain protectant was distinguished by low rate of degradation on the grain under practical storage conditions. One hundred and eighty days after treatment at an application rate of 0.5 mg kg^-1, the residues were between 0.03 and 0.2 mg kg^-1 in the various types of flour. Two hundred and seventy days after treatment at a rate of 4 mg kg^-1, the residues in the flour were in the range of 0.4-1.5 mg kg^-1.     

Carbendazim and metalaxyl residues in post-harvest treated apples

Bramley apples were treated with Ridomil mbc 60 WP, containing carbendazim and metalaxyl, at half and full rate application at 10 and 20°C, and with diphenylamine to control disease during storage. Carbendazim and metalaxyl residues were determined by HPLC and GC/MS, respectively, in apple core, flesh and peel at the initial time, 3 and 6 months after storage under controlled atmosphere conditions of 4.5°C, 5% CO₂ and 1% O₂. The concentration of carbendazim residues in apple flesh was ≤ 0.43 mg kg^-1 in all treatments; the mean concentrations in apple core and peel were 2.2 ±1.1 and 5.2 ±2.2 mg kg^-1, respectively. The MRL for carbendazim in apple was 2.0 mg kg^-1. The concentration of metalaxyl residues in apple flesh was ≤ 0.22 mg kg^-1; the mean concentrations in apple core and peel were 0.41 ±0.18 and 0.79 ±0.94 mg kg^-1, respectively. The MRL for metalaxyl in apple was 1.0 mg kg^-1. The temperature of the fungicide solution had little effect on the carbendazim residues but did have some effect on metalaxyl residues. Carbendazim residue content per apple was decreased when diphenylamine was included. A change in the ratio of carbendazim to metalaxyl was noted in the flesh, core and peel of the stored apple. The ratio of carbendazim to metalaxyl was 5:1 in the fungicide mix as applied. The ratio remained fairly constant in the core during storage. However, the ratio changed significantly in the peel and, to a lesser extent, and in a different direction, in the flesh. In the peel, the ratio was around 15:1 at 3 months of storage and 12:1 after 6 months of storage, whereas for flesh the ratios were 2:1 and 4:1, respectively.     

稻米中总砷及无机砷含量的测定与分析

采用氢化物原子荧光光度法测定13份稻米样品中的总砷和无机砷含量,结果表明：所测稻米样品中均检出总砷与无机砷,总砷含量范围为0.06~0.20 mg/kg,无机砷含量范围为0.039~0.150 mg/kg,无机砷占总砷的含量为50.0%~93.1%,无机砷含量在国家限量卫生标准以内;未冲洗大米样品中总砷含量仅为糙米的72.7%~90.0%,无机砷含量为糙米的62.7%~87.7%;多次冲洗的大米样品中总砷含量仅为未冲洗大米的75.0%~91.7%,无机砷含量为83.0%~93.6%。提高加工精度和用水淘洗均能在一定程度上降低总砷与无机砷的含量,减轻人们食用后对身体的危害。     

Cadmium and mercury in cephalopod molluscs: Estimated weekly intake

Cadmium and mercury concentrations were measured in the flesh and hepatopancreas of different species of cephalopod molluscs (European squid, common octopus, curled octopus, horned octopus, pink cuttlefish, common cuttlefish) in order to establish whether the concentrations exceeded the maximum levels fixed by the European Commission. In hepatopancreas, the levels of cadmium were substantially higher than those in flesh (flesh 0.11-0.87 µg g^-1 wet weight, hepatopancreas 2.16-9.39 µg g^-1 wet weight), whilst the levels of mercury (flesh 0.13-0.55 µg g^-1 wet weight, hepatopancreas 0.23-0.79 µg g^-1) were approximately double those in flesh. Concentrations exceeding the maximum permitted limit of cadmium were found in 39.8 and 41.0% of common octopus and pink cuttlefish flesh, respectively. For mercury, concentrations above the limit were found only in octopuses, and precisely in 36.8, 50.0 and 20.0% of flesh samples of common, curled and horned octopus, respectively. In the hepatopancreas, concentrations of cadmium and mercury were above the proposed limits in all the samples examined. The estimated weekly intake of between 0.09 and 0.49 µg kg^-1 body weight for cadmium and between 0.05 and 0.24 µg kg^-1 body weight for mercury made only a small contribution to the provisional tolerable weekly intake (cadmium 1.3-7.0%, mercury 1.0-4.8%) set by the WHO.     

The fate of added nitrate used in the manufacture of Emmental cheese

The aim of this study was to observe the dynamics of nitrates and nitrites during the six stages of manufacture of Emmental cheeses. Samples were taken of untreated milk, of pasteurized milk, of milk with nitrates added, of pressed cheese curd, of whey, of maturing cheese and of the final product. The samples were drawn from a commercial operation in a cheese factory in the eastern part of Slovakia. The mean NaNO₂ content in untreated and in pasteurised milk was 0.2 and 0.1 mg kg^-1, respectively and the mean NaNO₃ content was 0.9 and 0.9 mg kg^-1 respectively. Nitrates were added to the milk to prevent 'blowing' of hard cheese by micro organisms. In milk with nitrate added the mean content was 81.2 mg kg^-1 NaNO₃; the maximum value being 90.0 mg kg¹ NaNO₃. After pressing, the mean value of nitrate was found to be 20.6 mg kg^-1 NaNO₃. A considerable quantity of nitrates passed into the whey, where the mean nitrate content was 67.0 mg kg^-1 NaNO₃. The final product had a markedly decreased content of nitrates (3.3 mg kg^-1 NaNO₃) and nitrites (0.2 mg kg^-1 NaNO₂) when compared with the values in cheese during maturation (11.3 mg kg^-1 NaNO₃; 0.4 mg kg^-1 NaNO₂).     

Total and methylmercury residues in tuna-fish from the Mediterranean sea

This study was carried out to determine the current levels of total mercury and methylmercury in the muscle tissue of albacore (Thunnus alalunga) and bluefin tuna (Thunnus thynnus) caught in the Mediterranean sea with the purpose of ascertaining whether the concentrations exceeded the maximum level fixed by the European Commission Decision. Total mercury concentrations ranged from 0.84 to 1.45 mg kg^-1 w.w. (av. 1.17 mg kg^-1 w.w.) and from 0.16 to 2.59 mg kg^-1 (av. 1.18 mg kg^-1 w.w.) in the muscle of albacore and bluefin tuna, respectively. In 78.6% of albacore and in 61.1% of bluefin tuna analysed, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg = 1 µg g^-1 wet wt). In the two species, mercury was present almost completely in the methylated form, with percentages between 77 and 100% (av. 91.3%) in albacore and between 75 and 100% (av. 91%) in bluefin-tuna. In order to assess the potential health impact, the estimated weekly intake was calculated. The estimated weekly intake was far above the established Provisional Tolerable Weekly Intake for both species.     

Three-year study of fenthion and dimethoate pesticides in olive oil from organic and conventional cultivation

Residues of fenthion and dimethoate pesticides were determined in organic and conventional olive oils by liquid-liquid and solid-phase extractions with subsequent gas chromatography and mass spectrometric analysis. The olive oil samples were collected from Crete during 1997-99. The average concentrations of fenthion in conventional olive oils were 0.1222, 0.145 and 0.1702 mg kg^-1, and for dimethoate were 0.0226, 0.0264 and 0.0271 mg kg^-1 for 1997, 1998 and 1999, respectively. The average concentrations of fenthion in organic olive oils were 0.0215, 0.0099 and 0.0035 mg kg^-1 for 1997, 1998 and 1999, while for dimethoate they were 0.0098, 0.0038 and 0.0010 mg kg^-1, respectively. All the olive oils contained residue levels lower than the maximum resi-due levels according to the FAO/WHO Codex Alimentarius. The organic olive oil contained significantly lower concentrations of the two pesticides. The levels of fenthion and dimethoate in organic olive oils exhibited a decreasing trend following the implementation of the new cultivation method. We propose procedures that should be established in the organic cultivation in order to maximize its effectiveness.     

Arsenic in rice and diets of children

Levels of arsenic in Australian and imported rice (n = 36) were evaluated using inductively coupled plasma mass spectrometry (ICP-MS) for total arsenic and a hyphenated high-performance liquid chromatography ICP-MS system for arsenic species. The study also assessed the daily intake of total As from diets of healthy children (n = 15), collected over three consecutive days. A wide variation of total As levels (range: <0.05–0.42 mg/kg) in Australian and imported rice was found. The mean level of total As (0.24 ± 0.09 mg/kg, n = 10) in the Australian rice was relatively higher than imported rice from other countries (0.09 ± 0.04 mg/kg, n = 26). The mean level (0.25 ± 0.08 mg/kg, n = 7) of dimethylarsenic acid was considerably higher than that of inorganic As (III) (0.07 ± 0.03 mg/kg, n = 7) in the Australian rice. Children’s daily intakes of total As varied widely, ranging from 1.7 to 31.2 (11.5 ± 8.9 µg/day), which was comparable to other countries.