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     

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 and micronutrient elements in organic,brown and polished rice in Brazil

Concentration levels of As, Cd, Hg, Pb, Tl, Sn, Sb Co, Cu, Mn, Se, Zn, Cr, Ni and Mo in different types of rice cultivated in irrigated fields in Brazil were evaluated. Arsenic, Cd, Pb, Zn, Mn and Cu were found in higher concentrations in brown rice samples, suggesting the prevalence of these elements in the bran. Meanwhile, lower concentrations of Pb, Mo, Cr, Se and Co were found in parboiled rice. Organic rice did not differ of cultivated conventionally rice. Thallium, Hg and Sb were not detected in any rice sample whose limits of detection were 0.7 μg kg^?1, 2.5 μg kg^?1 and 8 μg kg^?1, respectively. The concentrations of the investigated elements were compared with those reported for polished rice and brown rice from other countries, unveiling concentrations in general at the same level for rice produced at non-contaminated sites.     

Sequential Determination of Cd, Cu and Pb in Tea Leaves by Slurry Introduction to Thermospray Flame Furnace Atomic Absorption Spectrometry

A simple procedure for the sequential determination of Cd, Cu and Pb in tea leaves by slurry introduction to thermospray flame furnace atomic absorption spectrometry was developed. Detection limits were 0.05 mg?kg^?1 for Cd, 2.1 mg?kg^?1 for Cu and 0.68 mg?kg^?1 for Pb using 0.67 % (m/v) slurries (100 mg/15 mL).     

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.     

Essential elements and contaminants in tissues of commercial pelagic fish from the Eastern Mediterranean Sea

BACKGROUND: It is important to determine the concentrations of essential and non‐essential metals in fish for human health. The essential elements and contaminants (Pb and Cd) were determined seasonally in the muscle and liver of some pelagic fish species round herring (Etrumeus teres), chub mackerel (Scomber japonicus), golden grey mullet (Liza aurata) and Mediterranean horse mackerel (Trachurus mediterraneus) from the Iskenderun Bay, Eastern Mediterranean Sea. RESULTS: The Na, K, Ca and Mg were the most abundant elements in muscle and liver tissues. The Na, K, Ca and Mg concentrations in fish tissues were between 51.7 and 3426 mg kg^?1. Muscle accumulated the lowest levels of elements. Trace element and contaminant levels in muscle were highest in spring and summer. The Cu, Zn and Cr concentrations were highest in summer. The Ni, Mn and Fe concentrations were highest in spring. The maximum Pb concentrations in the muscle and liver of fish species was 0.39 and 0.80 mg kg^?1 in autumn. The maximum Cd concentration in the muscle of fish was 0.27 mg kg^?1 in spring and the maximum Cd concentration in the liver was 0.78 mg kg^?1 in summer. CONCLUSION: The Cr, Pb, Cd, Cu and Zn levels in muscle were found to be lower than permissible limits reported by various authorities. Estimated weekly and daily intake for Pb and Cd by consumption of fish muscle were far below the PTWI and PTDI values established by FAO/WHO. Copyright © 2009 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.     

Lead and cadmium in mangrove root crab (Goniopsis cruentata), in natura and at food processing stages

ABSTRACT

Lead (Pb) and cadmium (Cd) were determined in mangrove root crab (Goniopsis cruentata) tissues (in natura) and in two culinary preparations by graphite furnace atomic absorption spectrometry. Mangrove root crab samples from three sampling sites along the Jaguaripe River, Bahia, Brazil, where lead-glazed ceramics are produced, and from two commercial preparations were collected or purchased in March and April 2016. Cd levels in raw and processed samples were below the methods’ limits of detection (0.016 mg kg^?1), while Pb levels in the raw tissues were determined only in the gills (0.67 mg kg^?1) and in the hepatopancreas (0.14 mg kg^?1). However, Pb levels increased from 0.05 to 2.84 mg kg^?1 in boiled/sorted muscle and in the traditional stew (with a 57-fold increase), respectively. Pb levels augmented significantly in the processed food due to migration of Pb used in the glazing of cooking ceramic utensils, surpassing the Brazilian and international safety limits.     

Chemical composition and toxic trace element composition of some Nigerian edible wild mushrooms

Two essential amino acids (methionine and tryptophan); anti‐nutritional factors (tannin and trypsin inhibitor) and toxic elements (Pb, Cd, Ni, As, Hg and Cr) were determined spectrophotometrically from five edible wild mushrooms. The tryptophan content was between 1.00 and 1.82 g (100 g)^?1 but methionine was low at 0.26–1.38 g (100 g)^?1. Tannin content was high (30.3–40.0 mg g^?1) but trypsin inhibitor was low (22.0–39.5 TIU g^?1). Trace elements analysis reviled Pb (0.34–5.06 mg kg^?1) to be the highest of all the trace elements. Cd was (0.06–1.70 mg kg^?1), Ni (0.26–2.08 mg kg^?1), As (0.17–0.92 mg kg^?1), Hg (0.01–0.05 mg kg^?1) and Cr (0.04–0.22 mg kg^?1). These mushrooms are nutritious but must be well processed to eliminate or at least reduce the levels of tannin and Pb to improve their nutritional values.     

Metal levels in economically important bivalve species from Turkey

Concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were determined in economically important bivalve species: oyster (Ostrea edulis), wedge clam (Donax trunculus), manila clam (Ruditapes philippinarium) and warty clam (Venus verrucosa) from the Marmara and Aegean seas. Samples were collected seasonally between 2008 and 2009. Metal levels of bivalves were found in the following ranges: As 0.02–3.40, Cd 0.02–2.80, Cr 0.19–0.82, Cu 0.82–25.06, Hg?<?LOD–0.12, Ni 0.09–0.73, Pb 0.05–4.16 and Zn 6.85–899?mg?kg^?1. The most abundant elements were Zn?>?Cu?>?As. In addition, the results showed that oysters had the highest concentrations of Zn in all seasons. The next abundant heavy metal detected was Cu in oyster and other clam species. It was concluded that in the future, these metals should be monitored regularly.     

Aluminium,nickel, cadmium and lead in candy products and assessment of daily intake by children in Spain

Aluminium (Al), nickel (Ni), cadmium (Cd) and lead (Pb) levels in a total of 263 samples of 12 types of candies widely consumed in Spain, were evaluated. Samples were analysed using an ICP-MS method after acidic sample mineralization. Concentration ranges of Al, Ni, Cd and Pb were 21.28–62.91 µg g^?1, 0.40–1.27 µg g^?1, 0.12–1.01 µg g^?1 and 1.03–7.14 µg g^?1, respectifgvely. Statistically significant positive correlations were calculated between concentrations of Ni–Al and Pb–Cd (p-values < 0.05). Taking into consideration the relatively high metal content, together with the high caloric density of these products, as well as high content of particular nutrients such as sugars that can induce development of certain pathologies like obesity and caries, indicate that frequent consumption of candy products is not recommended.     

Toxic metal content in 52 frequently prescribed herbal medicines on the Korean market

This study was conducted to investigate the toxic metal content (Pb, As, Cd and Hg) of 52 frequently prescribed herbal medicines and to identify herbal medicines that exceed the Korea Food and Drug Administration (KFDA) maximum limits. A total of 3534 samples, including 1966 domestic samples and 1568 imported samples, were analysed using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Total amounts of Pb, As, Cd and Hg were significantly different between domestic (0.63 mg kg^?1) and imported (0.81 mg kg^?1) medicines (p < 0.05). Among the 52 kinds of samples, 4 kinds of herbs required quality control for Pb and 12 kinds of herbs required quality control for Cd. No sample contained As and Hg above the limits.     

Determination of toxic and essential elements in sunflower honey from Thrace Region,Turkey

The aim of this study was to determine the levels of copper (Cu), manganese (Mn), zinc (Zn), iron (Fe), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni) and selenium (Se) in sunflower honeys obtained from Thrace Region of Turkey. Trace and toxic element determination was performed by atomic absorption spectrometry after microwave digestion. The accuracy of the method was checked by the standard reference material, NIST‐SRM 1515 Apple leaves. The maximum contents of trace and toxic elements in honey samples from Kesan (polluted area) were found as 0.46, 0.82, 1.98, 14.0, 9.86 μg kg^?1, 0.48 mg kg^?1, 137, 115 and 290 μg kg^?1 for Cu, Mn, Zn, Fe, Cd, Pb, Cr, Ni and Se, respectively.     

Toxic and essential elements in butter from the Black Sea region,Turkey

In this study, 88 randomly selected samples of butter produced in the Black Sea region of Turkey were purchased from different retail markets during different periods and investigated for toxic and essential elements content. Quantitative analyses of elements in the samples were performed using an inductively coupled plasma-mass spectroscopy (ICP-MS). Mean concentrations of As, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn in the butter samples were 18.93, 100.32, 384.66, 4199.1, 887.47, 168.64, 56.13, 16.34 and 384.66 µg kg^?1, respectively. Cd and Co were detected in 19 (mean content 0.29 µg kg^?1) and 81 (mean content 3.81 µg kg^?1) samples of 88 butter samples, respectively. However, the dietary intake of these elements by the population of the Black Sea region is currently well below the dietary reference intake (DRI) and provisional tolerable weekly intake (PTWI) levels of essential and toxic elements.     

Metal Determination in Tea,Wheat, and Wheat Flour Using Diluted Nitric Acid,High-Efficiency Nebulizer,and Axially Viewed ICP OES

This study deals with the determination of Cu, Al, Cd, Mo, Pb, V, Sr, Ni, Cr, Co, Zn, Mn, and Fe in tea, wheat grain, and wheat flour by inductively coupled plasma optical emission spectrometry (ICP OES) with axially viewed plasma. Ultrasonic nebulization (USN) or pneumatic nebulization with aerosol desolvation (PN/DES) is used to introduce the sample solution into the ICP. Solutions of nitric acid (HNO₃) with different concentrations of the acid (4.6 to 9.1 mol L^?1) and hydrogen peroxide (H₂O₂) were investigated for sample decomposition in closed vessel (made of TFM-polytetrafluoroethylene (PTFE)) under microwave irradiation. Certified reference materials of tea, wheat flour, or bush branches and leaves were analyzed (0.5 g of sample in the presence of 2 mL H₂O₂?+?3 mL HNO₃?+?2 mL H₂O). Element concentrations found were in accordance with those certified in most cases, excepting for Al and V. Plasma-related matrix effects were not observed as denoted by the signal of the Ar 420.069-nm emission line. The analyte recoveries in spiked chamomile tea and wheat flour samples ranged from 87 to 107 %. By using USN, the limits of quantification (LOQs) of Cu, Al, Cd, Mo, Pb, V, Sr, Ni, Cr, Co, Zn, Mn, and Fe were 0.033, 0.006, 0.023, 0.33, 2.0, 0.33, 0.001, 0.33, 0.07, 0.033, 0.07, 0.001, and 0.02 μg g^?1, respectively. Quite similar LOQs were obtained for both nebulizers employed, with the exception of Pb; the LOQ of Pb was three times lower by using PN/DES. Commercialized tea, wheat grain, and wheat flour were analyzed, and the concentrations found were reported.     

Trace elements in edible tissues of three shrimp species (Penaeus semisulcatus,Parapenaeus longirostris and Paleomon serratus)

Accumulation levels of trace elements in edible tissues of three shrimp species (Penaeus semisulcatus, Parapenaeus longirostris and Paleomon serratus) from the Gulf of Antalya, Turkey were investigated. Copper (Cu), cadmium (Cd), zinc (Zn), iron (Fe) and manganese (Mn) concentrations were determined by atomic absorption spectrophotometry. The lowest Cu (1.33 mg kg^?1) and Cd (0.23 mg kg^?1) and highest Mn (1.52 mg kg^?1) concentrations were found in P. longirostris, the lowest Zn (6.25 mg kg^?1), Fe (1.84 mg kg^?1) and Mn (0.25 mg kg^?1) concentrations in P. serratus and the highest Cu (6.19 mg kg^?1), Cd (2.36 mg kg^?1), Zn (30.84 mg kg^?1) and Fe (33.89 mg kg^?1) concentrations in P. semisulcatus. The Cd levels detected in P. semisulcatus and P. serratus were above legislative limits. Our results show that there were significant differences in trace element concentrations among the three shrimp species. The highest levels of the five trace elements investigated, with the exception of Mn, were found in edible tissue of P. semisulcatus. Copyright © 2007 Society of Chemical Industry     

Occurrence of glyphosate in beer from the Latvian market

A sensitive LC-MS/MS method for the determination of glyphosate in beer has been developed, validated, and applied to analyse 100 beer samples from 24 different producers and distributors in Latvia. The selected samples represented most beer brands and varieties sold in local supermarkets. Different procedures for sample preparation and chromatographic separation were compared. The final version of the method consisted of solid phase extraction, chromatographic separation on aminopropyl stationary phase, and detection using tandem mass spectrometry. The concentration of glyphosate in beer varied from below the LOD of 0.2 μg kg^?1 up to 150 μg kg^?1, higher than previously reported. Significantly higher (p < 0.01) content of glyphosate was observed in beers that did not have the country of production disclosed on the label and were sold in local supermarkets by distributors from Latvia (1.8 μg kg^?1 median concentration in locally produced beer, 6.7 μg kg^?1 in beer of undisclosed origin).     

Saxitoxins and okadaic acid group: accumulation and distribution in invertebrate marine vectors from Southern Chile

Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an history of HABs spanning more than 30 years, but there is limited investigation of the bioaccumulation of marine toxins in the bivalves and gastropods from the Region of Aysén. In this study, bivalves (Mytilus chilenses, Choromytilus chorus, Aulacomya ater, Gari solida, Tagelus dombeii and Venus antiqua) and carnivorous gastropods (Argobuccinum ranelliformes and Concholepas concholepas) were collected from 28 sites. Researchers analysed the accumulation of STX-group toxins using a LC with a derivatisation post column (LC-PCOX), while lipophilic toxins (OA-group, azapiracids, pectenotoxins and yessotoxins) were analysed using LC-MS/MS with electrospray ionisation (+/–) in visceral (hepatopancreas) and non-visceral tissues (mantle, adductor muscle, gills and foot). Levels of STX-group and OA-group toxins varied among individuals from the same site. Among all tissue samples, the highest concentrations of STX-group toxins were noted in the hepatopancreas in V. antiqua (95 ± 0.1 μg STX-eq 100 g^?1), T. dombeii (148 ± 1.4 μg STX-eq 100 g^?1) and G. solida (3232 ± 5.2 μg STX-eq 100 g^?1; p < 0.05); in the adductor muscle in M. chilensis (2495 ± 6.4 μg STX-eq 100 g^?1; p < 0.05) and in the foot in C. concholepas (81 ± 0.7 μg STX-eq 100 g^?1) and T. dombeii (114 ± 1.2 μg STX-eq 100 g^?1). The highest variability of toxins was detected in G. solida, where high levels of carbamate derivatives were identified (GTXs, neoSTX and STX). In addition to the detected hydrophilic toxins, OA-group toxins were detected (OA and DTX-1) with an average ratio of ≈1:1. The highest levels of OA-group toxins were in the foot of C. concholepas, with levels of 400.3 ± 3.6 μg OA eq kg^?1 (p < 0.05) and with a toxic profile composed of 90% OA. A wide range of OA-group toxins was detected in M. chilensis with a toxicity < 80 μg OA eq kg^?1, but with 74% of those toxins detected in the adductor muscle. In all evaluated species, there was no detection of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods. In addition, the STX-group and OA-group toxin concentrations in shellfish was not associated with the presence of HAB. The ranking of toxin concentration in the tissues of most species was: digestive glands > mantle > adductor muscle for the STX-group toxins and foot > digestive gland for the OA-group toxins. These results gave a better understanding of the variability and compartmentalisation of STX-group and OA-group toxins in different bivalve and gastropod species from the south of Chile, and the analyses determined that tissues could play an important role in the biotransformation of STX-group toxins and the retention of OA-group toxins.     

Use of Multivariate Optimization to Develop Methods for Direct Copper and Lead Determination in Breast Milk by Graphite Furnace Atomic Absorption Spectrometry

A direct method for lead and copper determination in breast milk by graphite furnace atomic absorption spectrometry, using aqueous calibration, was proposed in this study. Samples were diluted with hydroximethylaminomethane 80 %?v/v, pH 8. The dilution determination for Pb and Cu was 1:1 and 1:9, respectively. Fractional factorial (2^4?1) and central composite designs were used to optimize experimental conditions (pyrolysis and atomization temperatures, pyrolysis time, and modifier) using 10 μL samples introduced into a graphite furnace. The methods allowed for copper and lead determination under optimized conditions with an aqueous calibration curve between 0 and 180 μg L^?1 for Cu and 0 and 48 μg L^?1 for Pb. The detection limits were 0.92 μg L^?1 and 6.4 μg L^?1 for Pb and Cu, respectively. Intra and inter-assay studies revealed coefficients of variation of 5.0 and 6.3 %, and 6.4 and 5.5 % for Pb and Cu, respectively. Recovery studies at three concentration levels (three consecutive days, n?=?7/day) presented results between 107 and 109 % for Pb and 102 and 103 % for Cu. Good accuracy was obtained for both metals through recoveries studies using certified reference material (infant formula NIST® 1846). The method determined lead and copper in six samples and the concentrations ranged from 2.90 to 27.9 μg L^?1 for Pb and 384 to 1,212 μg L^?1 for Cu. While copper is an essential element, lead has no nutritional function and is cumulative at low concentrations. Therefore, safe, efficient, and validated methods should be available to determine its concentration in breast milk.     

Aflatoxins and heavy metals in animal feed in Iran

The occurrence of aflatoxin (aflatoxin B₁, aflatoxin B₂, aflatoxin G₁ (AFG₁) and aflatoxin G₂ (AFG₂)) and heavy metal (Pb, Cd, As and Hg) contamination was determined in 40 industrially produced animal feed samples which were collected from the southwest of Iran. The results indicated that 75% of samples were contaminated by four aflatoxins and the level of AFB₁ and sum of aflatoxins were higher than the permissible maximum levels in Iran (5 and 20 µg kg^?1, respectively) in all feed samples. A positive correlation was found between four types of aflatoxins in all the tested samples (p < 0.01) and the positive correlation between AFG₁ and AFG₂ was significant (r² = 0.708). All feed samples had lead concentrations lower than the maximum EU limit, while 5%, 17% and 42.5% of feed samples had As, Cd and Hg concentrations higher than the maximum limits, respectively.