Soil and vegetable compositional relationships of eight potentially toxic metals in urban garden fields from northern Nigeria

BACKGROUND: Human exposure to heavy metals is attributed to consumption of vegetables raised in polluted soil environment. We examined the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in soils and lettuce (Latuca sativa) and amaranthus (Amaranthus caudatus) in 15 garden fields under long‐term wastewater irrigation. RESULTS: The concentrations of As (0.3–2.1 mg kg^?1), Cd (0.07–0.3 mg kg^?1), Co (4.6–9.1 mg kg^?1) and Cr (21.6–36.2 mg kg^?1) in the gardens were consistent with background concentrations in soils, but Ni (12.6–25.7 mg kg^?1), Cu (12.5–24.6 mg kg^?1), Pb (25.7–71.6 mg kg^?1) and Zn (52.3–158 mg kg^?1) concentrations were double the concentrations normally encountered in arable fields in the region. The concentrations of Cd and As in the vegetables were within safe limits, but Co (0.14–0.67 mg kg^?1 fresh weight (fw)) and Ni (1.0–2.7 mg kg^?1 fw) concentrations in lettuce were relatively high for leaf vegetables. The concentration of Pb (0.65–4.80 mg kg^?1 fw) was above safe limit of 0.3 mg kg^?1 fw, while the concentrations of Cu (1.3–2.7 mg kg^?1 fw and Zn (10.2–23.6 mg kg^?1 fw) were close to the unsafe limits for leaf vegetables. There were no strong linear correlations between soil metal concentrations and bio‐concentrations in the vegetable crops. CONCLUSION: We surmise that leaf vegetables can accumulate metals in their tissues to unsafe levels even when total metal concentrations in these soils are below the allowable concentrations in agricultural soils. Copyright © 2008 Society of Chemical Industry     

Intake of essential and non-essential elements from consumption of octopus,cuttlefish and squid

Total concentrations of essential (Cu, Zn, Se and Cr) and non-essential (Hg, Cd, Pb and As) trace elements were measured in the flesh and hepatopancreas of Octopodidae (Eledone moschata, Eledone cirrhosa, Octopus salutii), Sepiidae (Sepia elegans, Sepia orbignyana) and Loliginidae (Illex coindeti, Loligo vulgaris) from the Mediterranean Sea. As expected, the hepatopancreas showed higher metal concentrations than flesh; the only exceptions were Hg and As, which were equally distributed in the two tissues. Regarding the edible portion, the highest toxic metal concentrations were in Octopodidae (Hg: 0.44, Cd: 0.49, Pb: 0.10 µg g^?1 wet weight) and Sepiidae (Hg: 0.27, Cd: 0.50, Pb: 0.12 µg g^?1 wet weight), while Loliginidae tended to accumulate less metal, especially Hg (Hg: 0.11, Cd: 0.30, Pb: 0.05 µg g^?1 wet weight). The other elements showed a heterogeneous distribution among the different cephalopod families. Loliginidae showed the highest Se concentrations (1.18 µg g^?1 wet weight), Octopodidae of Cu (37.37 µg g^?1 wet weight) and Zn (42.00 µg g^?1 wet weight) and Sepiidae of As (61.43 µg g^?1 wet weight), while Cr was uniformly distributed among the various families (0.38–0.43 µg g^?1 wet weight). In these seafoods, the concentrations of essential and non-essential elements were within the prescribed limits set by various authorities, except for Cu and As. Health risks posed by toxic elements to humans via dietary intake of these mollusks were assessed on the basis on Provisional Tolerable Weekly Intake (PTWI), while the estimated intakes of essential elements were compared to Dietary Reference Intakes (RDIs). A 70-g serving of these mollusks was shown to provide a large contribution to Cd intake (0.89 µg kg^?1 body weight), corresponding to 35.6% of PTWI. Concerning the essential elements, the consumption of these mollusks made an important contribution to daily dietary intake of Se, Cu and Zn.     

Survey and risk assessment of trace elements in foods from Taiwan containing red mould rice (Monascus) by ICP-MS

The concentrations of seven trace elements (As, Cd, Cr, Pb, Se, Cu and Zn) in 93 red mould rice (Monascus) food samples in Taipei, Taiwan, were determined by inductively coupled plasma-mass spectrometry (ICP-MS) after wet digestion. The results, calculated in mg?kg^?1 (wet weight) for each sample, revealed the general scenario of food safety in Taiwan: As (0.005–12.04), Cd (<0.0005–2.22), Cr (0.014–6.95), Cu (0.012–8.70), Pb (0.001–0.64), Se (<0.001–1.29) and Zn (0.020–67.02). Three food samples were identified with As concentrations higher than regulatory limits: a dietary supplement sample and a seaweed sample with As concentrations that exceeded the limit of Taiwan's health food standard of 2?mg?kg^?1, and a canned eel sample with an As concentration that exceeded the limit of Canada's fish standard of 3.5?mg?kg^?1. This study suggests that the estimated intakes of these seven trace elements from the consumption of foods containing Monascus pose little risk, as the trace element contents in the majority of samples were lower than the permissible/tolerable intakes per week according to the guidelines recommended by the Food and Agricultural Organization/World Health Organization (FAO/WHO). Moreover, their concentrations in foods containing Monascus differ widely for different food varieties, suggesting that external contaminants and raw materials are the main sources of trace elements. This study shows that ICP-MS is a simple method proposed for the determination of As, Cd, Cr, Pb, Se, Cu, and Zn in foods containing Monascus.     

Cadmium and lead in female cattle livers and kidneys from Vojvodina,northern Serbia

ABSTRACT

Concentrations of cadmium (Cd) and lead (Pb) were determined in livers (n = 52) and kidneys (n = 52) of female cattle (345–2717 days old) from dairy farms in the region Vojvodina. Cd and Pb were analysed by inductively coupled plasma-optical emission spectrometry, after microwave digestion. Cd and Pb concentrations did not exceed the Serbian and European maximum set limits in any sample. The Cd concentrations in the livers and kidneys ranged from 0.033 to 0.151 mg kg^?1 wet weight and from 0.055 to 0.510 mg kg^?1 wet weight, respectively. The corresponding Pb concentrations were 0.015-0.159 mg kg^?1 wet weight and 0.021-0.196 mg kg^?1 wet weight, respectively. Mean Cd and Pb concentrations were significantly lower (p < 0.001) in the liver (0.072 and 0.053 mg kg^?1 wet weight) than in the kidney (0.190 and 0.075 mg kg^?1 wet weight). There were good correlations between Cd in liver and Cd in kidney, Pb in liver and Pb in kidney, Cd level and age and Pb level and age in both tissues.     

Toxic (Pb,Cd, Hg) and essential (Fe,Cu, Zn,Mn) metal content of liver tissue of some domestic and bush animals in Ghana

Accumulation of toxic metals in liver, a rich natural source of essential elements, can present health risks to regular consumers of liver. A total of 35 fresh liver samples of cow, sheep, goat, pig, grass-cutter (Thryonomys swinderianus), gaint rat (Cricetomys gambianus), red deer (Cervus elaphus), chicken and antelope (Antilocapra americana) were obtained from three different markets in Accra and Kumasi, Ghana. Samples were analyzed using atomic absorption spectrometry and an automatic mercury analyzer. Levels of iron in the grass-cutter and pig of 500.5–645.4 mg kg^?1 were the highest in the animal livers examined. Mn concentrations were highest in grass-cutter and rat liver, ranging 16.5–30.2 mg kg^?1. The safe Cu and Zn permissible limits of 20 and 50 mg kg^?1 were exceeded in 70 and 75% of the liver samples, respectively. Generally, for each animal group studied, at least 50% of the sample livers exceeded the Cd permissible limit of 0.5 mg kg^?1. The levels of Pb, which ranged 1.3–13.8 mg kg^?1, exceeded the proposed European Commission (EC) limit of 0.5 mg kg^?1. Care must be taken by regular consumers of the iron-rich animal livers of grass-cutter, pig and rat because they also had the highest levels of Pb (in grass-cutter and pig) and Cd (in grass-cutter, rat and pig). The liver samples analyzed for Hg had values far below the permissible limit of 0.5 mg kg^?1.     

Elemental composition of commercial sea cucumbers (holothurians)

Toxic and essential elements in 11 different sea cucumber species were determined and compared with daily intake recommendations and maximum allowed levels. The contents of macro-elements contents in dried sea cucumber samples were found to be 25,000–152,000?mg?kg^–1 for Na, 4000–8600?mg?kg^?1 for Mg, 1100–5200?mg?kg^?1 for K, 15,000–68,000?mg?kg^?1 and 36,300–251,000?mg?kg^?1 for Cl. Trace element concentrations in dried sea cucumber samples were found to be 11–100?mg?kg^?1 for Zn, 41–660?mg?kg^?1 for Fe, 3–74?mg?kg^?1 for Cu, 1.1–16?mg?kg^?1 for Mn, 1.4–3.7?mg?kg^?1 for Se, 1.1–9.6?mg?kg^?1 for Cr, and 0.3–5.1?mg?kg^?1 for Ni. All sea cucumber species were rich sources of Na, Cl, Mg, Ca, Fe, Cu, Se and Cr for human consumption. Regarding contaminants, As, Cd and Pb concentrations in dried sea cucumbers were in the ranges of 1.1–6.1, 0.03–0.06 and 0.11–0.69?mg?kg^?1, respectively. Moreover, Hg values of 11 sea cucumbers were below the detection limit (0.01?mg?kg^?1).     

Determination of Chromium Species in Various Medicinal Plants Consumed in Hatay Region in Turkey

In this study, 22 species of medicinal plants (anise, centaury, chamomile, fennel, flax, green tea, indian hemp, laurel, licorice, linden, marestail, melissa, nettle, oat, red clover, riesenfenchel, rosehip, rosemary, sage, senna tea, yam, yarrow) were taken from five different local herbalists in Hatay. Chromium concentrations were determined by inductively coupled plasma-atomic emission spectroscopy. The highest chromium concentrations were detected in chamomile (4.21 ± 0.18 mg kg^?1), licorice (2.80 ± 0.12 mg kg^?1), melissa (2.71 ± 0.10 mg kg^?1), marestail (2.66 ± 0.10 mg kg^?1), and anise (1.98 ± 0.06 mg kg^?1). Minimal concentrations of chromium were found in riesenfenchel (0.33 ± 0.01 mg kg^?1), red clover (0.37 ± 0.01 mg kg^?1), centaury (0.43 ± 0.01 mg kg^?1), senna tea (0.49 ± 0.01 mg kg^?1), and linden (0.50 ± 0.01 mg kg^?1). Cr(III) and Cr(VI) concentrations in medicinal herbs were found in the range of 0.26–3.12 mg kg^?1 and 0.07–1.09 mg kg^?1, respectively.     

Survey of levels of cadmium in oysters,mussels, clams and scallops from the Pacific Northwest coast of Canada

Field and retail collections of bivalves from the Pacific Northwest, Canada, were analysed for cadmium concentrations by atomic absorption spectrophotometry (AAS). Both collections of varnish (Nuttallia obscurata) and manila (Venerupis philippinarum) clams contained cadmium concentrations of less than 0.5 µg g^?1, well below international safety guidelines of 1 and 2 µg g^?1 wet weight cadmium for the European and Hong Kong markets, respectively, as well as the 2 µg g^?1 safety guideline set by the Codex Alimentarius Commission (CAC). Cadmium concentrations in retail collections of the Pacific oyster, Crassostrea gigas, were generally above 2 µg g^?1 wet weight (range = 1.5–3.56 µg g^?1). Retail collections of the mussel, Mytilus spp., contained cadmium concentrations below the 2 µg g^?1 wet weight guideline, but not always the 1 µg g^?1 limit (range = 0.15?1.8 µg g^?1). However, field collections of Mytilus spp. contained cadmium concentrations between 0.35 and 4.00 µg g^?1 wet weight, and depending on sampling location, concentrations exceeded the CAC guidelines by more than two-fold. Locations where mussels had high cadmium concentrations correlated with regions that had previously reported high values for cadmium in Pacific oysters (r = 0.65; p < 0.05). Of the various shellfish analysed, the four species of scallops, Chlamys hastata, C. rubida, Crassadoma gigantea, and Patinopecten yessoensis, contained the greatest concentrations of cadmium, in excess of 5 µg g^?1 wet weight (range = 4.97–8.98 µg g^?1) with the greatest concentrations determined for C. gigantea. Cadmium concentrations in shellfish from the Pacific Northwest are greater than values reported for shellfish from other regions of the world and consumers need be aware of Health Canada consumption guidelines for shellfish from this region.     

Content of selenium, total and inorganic arsenic and bioaccessibility of arsenic in children diets of Mexico

BACKGROUND: The aim of this study was to evaluate the intake of selenium, total and inorganic arsenic and the bioaccessibility of arsenic in diets of Mexican schoolchildren using an in vitro method. RESULTS: Total and inorganic arsenic concentrations in the diets ranged from 0.05 to 1.15 mg kg^?1 dry weight (DW) and from 0.023 to 0.088 mg kg^?1 DW respectively, while selenium levels were between 0.08 and 0.20 mg kg^?1 DW. Daily intake of total and inorganic arsenic ranged from 0.15 to 10.49 µg day^?1 kg^?1 body weight (BW) and from 0.06 to 1.11 µg day^?1 kg^?1 BW respectively, while that of selenium varied from 0.29 to 2.63 µg day^?1 kg^?1 BW. Bioaccessibility of total and inorganic arsenic ranged from 4 to 97% (mean 44 ± 21.5%) and from 33 to 97% (mean 71 ± 22.5%) respectively. CONCLUSION: Inorganic arsenic levels in the diets were low. Therefore there appears to be a low risk of adverse effects resulting from excess inorganic arsenic intake from these diets. Copyright © 2011 Society of Chemical Industry     

Dietary exposure of Hong Kong secondary school students to total mercury and methylmercury from fish intake

Fish is the main source of dietary exposure to methylmercury (MeHg), which is a public health concern owing to its potential neurotoxicity. To evaluate the public health risk, this study estimated the total mercury (tHg) and MeHg exposure from fish intake in Hong Kong secondary school students. Median tHg and MeHg concentrations of 280 samples purchased from different commercial outlets (covering 89 species of whole fish and three types of canned tuna), together with the local food consumption data of secondary school students obtained by semi-quantitative food frequency questionnaire in 2000, were used to estimate dietary exposure from fish intake for the average and high consumer (95th percentile exposure). For tHg, the median concentration was 63 µg kg^–1 (range 3–1370 µg kg^–1) and estimated exposures ranged 0.5–0.6 µg kg^–1 body weight (bw) week^–1 for an average consumer and 1.6–1.9 µg kg^–1 bw week^–1 for a high consumer. For MeHg, median concentration was 48 µg kg^–1 (range 3–1010 µg kg^–1) and estimated dietary exposures were 0.4–0.5 µg kg^–1 bw week^–1 for an average consumer and 1.2–1.4 µg kg^–1 bw week^–1 for a high consumer. These values are below the respective provisional tolerable weekly intake (PTWI) established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA). The health risk is greater for high consumers since MeHg exposures may approach or exceed the PTWI when other dietary sources are taken into account.     

Influence of mercury bioaccessibility on exposure assessment associated with consumption of cooked predatory fish in Spain

BACKGROUND: Predatory fish tend to accumulate high levels of mercury (Hg). Food safety assessment of these fish has been carried out on the raw product. However, the evaluation of the risk from Hg concentrations in raw fish might be modified if cooking and bioaccessibility (the contaminant fraction that solubilises from its matrix during gastrointestinal digestion and becomes available for intestinal absorption) were taken into account. Data on Hg bioaccessibility in raw predatory fish sold in Spain are scarce and no research on Hg bioaccessibility in cooked fish is available. The aim of the present study was to evaluate Hg bioaccessibility in various kinds of cooked predatory fish sold in Spain to estimate their health risk. RESULTS: Both Hg and bioaccessible Hg concentrations were analysed in raw and cooked fish (swordfish, tope shark, bonito and tuna). There were no changes in Hg concentrations during cooking. However, Hg bioaccessibility decreased significantly after cooking (42 ± 26% in raw fish and 26 ± 16% in cooked fish), thus reducing in swordfish and tope shark the Hg concentration to which the human organism would be exposed. CONCLUSION: In future, cooking and bioaccessibility should be considered in risk assessment of Hg concentrations in predatory fish. Copyright © 2011 Society of Chemical Industry     

Analysis and risk assessment of arsenic,cadmium and lead in two fish species (Sardina pilchardus and Xiphias gladius) from Algerian coastal water

ABSTRACT

In this study, the levels of arsenic (As), cadmium (Cd) and lead (Pb) have been determined in the flesh of two species of fish, sardine (Sardina pilchardus) and swordfish (Xiphias gladius) fished in the Algerian coast. Quantification of As, Cd and Pb was carried out using an ICP-MS method and the results were compared with the thresholds set by national and international regulatory bodies. In a further step, the risk to consumers was assessed using estimated daily intake (EDI), target hazard quotient (THQ) and hazard index (HI).The average concentration of As and Pb was higher in sardine (1.82; 0.10 mg kg^?1 w.w., respectively), than in swordfish (1.10 mg kg^?1 w.w.; not determined), whereas the concentration recorded for Cd was the same for both species (0.01 mg kg^?1 w.w.). These concentrations are below maximum limits set in regulations. The THQs and HI were widely below 1. The consumption of these fish does not pose risk to the consumers.     

Comparison of Two Analytical Methods for the Analysis of Methylmercury in Fish

In this study, we compared a high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method and an isotope dilution gas chromatography mass spectrometry (ID-GC-MS) method for the analysis of methylmercury (MeHg) in fish samples. Using HPLC-ICP-MS, the limit of detection (LOD) was 2.0 ngHg?·?g^?1 for inorganic Hg and was 5.0 ngHg?·?g^?1 for MeHg. In comparison, the LOD for MeHg was 3.4 ngHg?·?g^?1 for using ID-GC-MS. Certified reference material (CRM) results agreed well with certified values for both methods. The mean recovery for analysis of CRM BCR 463 by HPLC-ICP-MS was 99?±?2.1 % for MeHg and was 103?±?2.1 % for total Hg. Two CRMs, BCR 463 and CRM DORM2, were analyzed by ID-GC-MS, the mean recovery of MeHg was 87?±?1.9 % for BCR 463, and the mean recovery of MeHg was 102?±?2.9 % for CRM DORM2. Matrix samples spiked with Hg or MeHg at various concentrations were analyzed by two methods. For HPLC-ICP-MS method, the mean recovery for MeHg spiked samples was 93?±?4.2 %. For ID-GC-MS method, the mean recovery for MeHg spiked samples was 91?±?5.2 %. A total of 19 predatory fish and 54 tuna fish samples were analyzed using both methods. No significant difference was observed between the MeHg data generated from both methods. The average relative standard deviation (RSD) between the two datasets for 19 predatory fish samples was 8.8 %. The average RSD between two datasets for 54 tuna fish samples was 4.4 %.The HPLC-ICP-MS method offers substantial advantages over the method of ID-GC-MS because the former method can determine the total mercury (Hg) and MeHg in a single chromatographic run and the analysis time is much shorter. The latter method is time consuming due to overnight digestion and having to conduct presample analysis for signal-matched isotope dilution spiking and requires more expensive isotope labeled reagents.     

Integrated processing of fresh Indian sea buckthorn (Hippophae rhamnoides) berries and chemical evaluation of products

An efficient pilot‐scale process was developed to produce nutraceutical products from fresh sea buckthorn (Hippophae rhamnoides) berries. Fresh berries were subjected to high‐pressure dewatering using a continuous screw press. The separated liquid phase containing 80–90% of pulp oil was clarified at 80 °C and centrifuged to obtain pulp oil, clear juice and sludge. The pulp oil yield was 2.7–2.8% of fresh berry weight with 66–70% extraction efficiency. The pulp oil was remarkably rich in carotenoids (2450–2810 mg kg^?1), tocopherols (1409–1599 mg kg^?1) and sterols (4096–4403 mg kg^?1), with a characteristic fresh berry flavour and 16:1 as the major fatty acid (45.6–49.1%). The clear juice obtained was free from oil and contained high amounts of vitamin C (1683–1840 mg kg^?1) and phytochemicals such as polyphenols (2392–2821 mg kg^?1) and flavonoids (340–401 mg kg^?1). Isorhamnetin (251–310 mg kg^?1) was the major flavonoid in the juice, along with quercetin (77–81 mg kg^?1) and kaempherol (12–16 mg kg^?1). The juice was very acidic (pH 3), with high concentrations of organic acids (30.8–36.0 g kg^?1). High‐performance liquid chromatography profiling of organic acids revealed quinic acid (18.1–19.9 g kg^?1) as the major acid in the juice. The seeds in the pressed cake were separated and extracted for oil using supercritical CO₂. Copyright © 2006 Society of Chemical Industry     

Characterization and prediction by near-infrared reflectance of mineral composition of rocket (Eruca vesicaria subsp. sativa and Eruca vesicaria subsp. vesicaria)

BACKGROUND: Minerals are essential for human nutrition and must be obtained from our diet. Crucifer vegetables are a good source of these nutrients. Our objectives were to determine the genetic variability for mineral content and to evaluate the use of near‐infrared reflectance spectroscopy (NIRS) for prediction of ashes and minerals among and within the rocket species Eruca vesicaria subsp. sativa and vesicaria. The minerals studied were iron (Fe), copper (Cu), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and zinc (Zn). RESULTS: The maximum mean values obtained for all the accessions (mean ± SE) were 235.5 ± 1.5 mg ashes kg^?1, 273.3 ± 4.2 mg Fe kg^?1, 18.1 ± 0.4 mg Cu kg^?1, 2.8 ± 0.1 g Na kg^?1, 71.6 ± 1.0 g K kg^?1, 64.6 ± 1.2 g Ca kg^?1, 6.8 ± 0.1 g mg kg^?1, 101.6 ± 1.2 mg Mn kg^?1, and 67.1 ± 0.4 mg Zn kg^?1 of dry weight. CONCLUSION: The statistical analysis showed significant differences for all the minerals, except Ca, for each accession studied individually and for accessions grouped within countries. The results indicate that NIRS can be used as a rapid screening method for determining total mineral, Fe, Na, K, and Zn in rocket. Copyright © 2011 Society of Chemical Industry     

Survey of pesticide residues in maize,cowpea and millet from northern Cameroon: part I

In northern Cameroon, the misuse of pesticides for pest control is common among small-scale farmers. Therefore, monitoring of pesticide residues was carried out on stored maize, cowpea and millet from eight localities. The determination of residues of organochlorines (lindane, α-endosulfan and β-endosulfan), organophosphorus compounds (malathion and pirimiphos-methyl), synthetic pyrethroids (permethrin) and carbamates (carbufuran) was performed using GC–ECD/NPD and GC–MS for confirmation. Organochlorine pesticides were detected more frequently and in higher concentrations, ranging from 0.02 ± 0.01 mg kg^?1 for β-endosulfan in millet to 9.53 ± 4.00 mg kg^?1 lindane in maize, than organophosphorus compounds, with concentrations varying from 0.04 ± 0.03 mg kg^?1 for pirimiphos methyl to 0.23 ± 0.38 mg kg^?1 for malathion in maize. Permethrin was found only in maize at 0.39 ± 0.23 mg kg^?1. No carbofuran was found. More than 75% of samples contained pesticide residues above the maximum residue limit (MRL); showing a potential human dietary risk related to consumption of these grains.     

Analysis of environmental chemical residues in products of emerging aquaculture industry in Uganda as case study for Sub-Saharan Africa

A study was conducted to analyse market-regulated heavy metals (lead, mercury and cadmium), organochlorine pesticides and total polychlorinated biphenyls (PCBs) in samples of 38 farmed fish comprising Nile tilapia (Oreochromis niloticus) (20 samples) and African catfish (Clarias gariepinus) (18 samples) from ten selected fish farms in Uganda. The goal of this case study was to understand the safety of aquaculture products from Sub-Saharan Africa. Lead was detected in all the 38 samples (maximum = 1.08 mg kg^?1 (dry weight)), mercury in 31 out of 38 samples (maximum = 0.35 mg kg^?1 (dry weight)), and cadmium in two samples (maximum = 0.03 mg kg^?1 (dry weight)). Total levels of PCBs were below the limit of detection of 0.02 mg kg^?1 (wet weight) in all the samples. Traces of 4,4′-dichloro-diphenyldichloroethylene (DDE) were detected in ten out of 38 samples (maximum = 0.01 mg kg^?1 (wet weight)) making it the most prevalent organochlorine pesticide. Other pesticides detected were: 4,4′-dichloro-diphenyl-trichloroethane (DDT) and endosulfan sulphate, which were found in one fish sample (both 0.002 mg kg^?1 (wet weight)). There was no statistically significant difference between the levels of lead and mercury in catfish and tilapia (t-test at p = 0.05). More catfish samples (eight) contained DDE as compared with tilapia (two). Cadmium, DDT and endosufan sulphate were only detected in catfish implying that catfish is more prone to contamination than tilapia. The levels of contaminants were below the US Food and Drug Administration (USFDA) action levels and European Union maximum residue limits (MRLs), indicating that such fish have the potential for export to these markets.     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.     

Total dietary intake of mercury in the Canary Islands,Spain

Estimating the risk associated with dietary intake of heavy metals by consumers is a vital and integral part of regulatory processes. The assessment of exposure to mercury shown in this paper has been performed by means of a study on the whole diet. Total mercury (Hg) levels were determined by cold vapour atomic absorption spectrometry (AAS) in 420 samples of regularly consumed food and drink. The total Hg concentrations measured in the different groups of food ranged from non-detectable to 119 µg kg^?1 w/w. The fish group had the highest concentrations of total Hg. All groups of food with regulated Hg content showed levels that were lower than the legally set values. The food consumption data used in the analysis were taken from the latest nutritional survey made in the Canary Islands, Spain. The estimated total Hg intake of local population (5.7 µg/person day^?1) did not exceed the provisional tolerable weekly intake (PTWI) limit of 0.3 mg week^?1 of total mercury (43 µg/person day^?1) fixed by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives. Fishery products contributed 96% of the total Hg intake. The mean Hg intake for each island in this archipelago, formed by seven, has also been calculated. Fuerteventura, Lanzarote and El Hierro are the islands with the highest level of Hg intake (7.0, 7,0 and 6.1 µg/person day^?1, respectively). La Palma Island, due to its low fish consumption, had the lowest level of Hg intake (4.5 µg/person day^?1), followed by La Gomera (5.4 µg/person day^?1), Tenerife (5.5 µg/person day^?1) and Gran Canaria (5.6 µg/person day^?1). A comparison has been made of the results obtained in this study with those found for other national and international communities.     

Nitrate and nitrite content in organically cultivated vegetables

The nitrate and nitrite content of leaf vegetables (Swiss chard, sea beet, spinach and cabbage), “inflorescence” vegetables (cauliflower) and fruit vegetables (eggplant and vegetable marrow) grown with organic fertilizers have been determined by a modified cadmium–Griess method. Samples were purchased from organic food stores as well as collected directly from an organic farm in Madrid (Spain). Nitrate levels were much higher in the leaf vegetables (especially Swiss chard species; average over the different samples and species of 2778.6 ± 1474.7 mg kg^{? 1}) than in inflorescence or fruit products (mean values between 50.2 ± 52.6 and 183.9 ± 233.6 mg kg^{? 1}). Following Swiss chard species, spinach (1349.8 ± 1045.5 mg kg^{? 1}) showed the highest nitrate content, and nitrite was found above the limit of detection in some samples only (spinach, 4.6 ± 1.0 mg kg^{? 1}; sea beet, 4.2 ± 0.7 mg kg^{? 1} and Swiss chard, 1.2 ± 0.4 mg kg^{? 1}). Some vegetables (spinach, cabbage and eggplant) had lower nitrate content in the samples harvested in summer, showing the influence of climatic conditions on the nitrate levels in a plant. The samples taken directly from the organic farm, with the exception of eggplant, had higher or slightly higher average nitrate values than samples purchased in the organic food stores, ranging from 117 to 1077%.