Tissue distribution of polybrominated diphenyl ethers in male rats and implications for biomonitoring

Polybrominated diphenyl ethers (PBDEs) are a class of widely used flame retardants which have been found to persist, bioaccumulate, and potentially affect development in animals. Exposure to PBDEs can be through both diet and the environment and is generally estimated by measuring PBDEs in blood, adipose tissue, muscle, or milk samples. Using rats as a model, we investigated tissue distribution of PBDEs after oral administration and evaluated a suitable matrix for body burden estimation. Male rats were administered dust or corn oil containing 8 or 6 microg PBDEs kg(-1) body wt, respectively, in the diet for 21 days (N=4 rats per treatment), and the concentration of 15 PBDEs were measured in various tissues, plasma, and feces. PBDEs were found in all tissues, including the brain, and showed no difference in distribution patterns between treatments for most PBDEs. Tri- to hexa-BDEs comprised >80% of the total PBDEs in the adipose, brain, kidney, lung, and residual carcass, but <40% in the liver and plasma. The ratio of the lipid-weight concentration of tri- to hexa-BDEs in adipose tissue, residual carcass, and plasma was 1:1:2. For the hepta- to nona-BDEs, lipid-weight concentrations increased from adipose tissue to residual carcass to plasma in the ratio 0.3:1:>4. BDE-209 was the dominant congener in the liver and plasma, but was not detected in the adipose tissue or carcass. In summary, the lower brominated congeners tended to distribute equally into lipids implying both adipose tissue and plasma would be suitable matrices for biomonitoring. Plasma was the best matrix for detection of the higher brominated congeners (especially BDE-209), although on a lipid-weight basis tended to overestimate the total body burdens.     

Determination of trichothecenes in duplicate diets of young children by capillary gas chromatography with mass spectrometric detection.

Trichothecenes are mycotoxins produced by several fungal genera, mainly Fusarium species, that can contaminate a wide range of cereals used for human and animal consumption. They are associated with various adverse health effects in animals and humans such as feed refusal, vomiting and immunotoxic effects. A method based on capillary gas chromatography with mass spectrometric detection was developed and validated in-house for the determination of nine trichothecenes in duplicate diets of young children. The trichothecenes were extracted from the sample matrix by water/ethanol (90/10). The extracts were cleaned by means of ChemElut and Mycosep columns. The cleaned extracts were evaporated to dryness and derivatized to trimethylsilyl ethers at room temperature. The residues were dissolved in iso-octane and washed with water. The final extracts were analysed for trichothecenes by GC-MS. The response was linear in the range tested (1-10 microg kg(-1)). Recoveries for the trichothecenes were between 70 and 111%, with the exception of nivalenol, which had a low recovery (34%). The limit of quantification for all trichothecenes was below 0.4 microg kg(-1). Seventy-four food samples from young children collected by 74 respondents in a duplicate diet study were analysed for trichothecenes with the developed method. The mean levels of deoxynivalenol, nivalenol, HT-2 toxin and T-2 toxin were 5.8, 0.3, 0.3 and 0.1 microg kg(-1), respectively. Based on the individual results, dietary intake calculations were made. For deoxynivalenol, the tolerable daily intake of 1 microg kg(-1) body weight was exceeded by nine respondents. For the combined intake of T-2 and HT-2 toxin, the temporary tolerable daily intake of 0.06 microg kg(-1) body weight was exceeded by nine respondents.     

Role of biofilms in sorptive removal of steroidal hormones and 4-nonylphenol compounds from streams

Stream biofilms play an important role in geochemical processing of organic matter and nutrients, however, the significance of this matrix in sorbing trace organic contaminants is less understood. This study focused on the role of stream biofilms in sorbing steroidal hormones and 4-nonylphenol compounds from surface waters using biofilms colonized in situ on artificial substrata and subsequently transferred to the laboratory for controlled batch sorption experiments. Steroidal hormones and 4-nonylphenol compounds readily sorb to stream biofilms as indicated by organic matter partition coefficients (K(om), L kg(-1)) for 17β-estradiol (10(2.5-2.8) L kg(-1)), 17α-ethynylestradiol (10(2.5-2.9) L kg(-1)), 4-nonylphenol (10(3.4-4.6) L kg(-1)), 4-nonylphenolmonoethoxylate (10(3.5-4.0) L kg(-1)), and 4-nonylphenoldiethoxylate (10(3.9-4.3) L kg(-1)). Experiments using water quality differences to induce changes in the relative composition of periphyton and heterotrophic bacteria in the stream biofilm did not significantly affect the sorptive properties of the stream biofilm, providing additional evidence that stream biofilms will sorb trace organic compounds under of variety of environmental conditions. Because sorption of the target compounds to stream biofilms was linearly correlated with organic matter content, hydrophobic partition into organic matter appears to be the dominant mechanism. An analysis of 17β-estradiol and 4-nonylphenol hydrophobic partition into water, biofilm, sediment, and dissolved organic matter matrices at mass/volume ratios typical of smaller rivers showed that the relative importance of the stream biofilm as a sorptive matrix was comparable to bed sediments. Therefore, stream biofilms play a primary role in attenuating these compounds in surface waters. Because the stream biofilm represents the base of the stream ecosystem, accumulation of steroidal hormones and 4-nonylphenol compounds in the stream biofilm may be an exposure pathway for organisms in higher trophic levels.     

4-hydroxy-2-alkenals in polyunsaturated fatty acids-fortified infant formulas and other commercial food products.

4-Hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE) were determined using selected ion-monitoring gas chromatography-mass spectrometry (GC-MS) in 56 kinds of commercially available PUFA-fortified foods including infant formulas and baby foods. HHE and HNE, each specifically coming from the oxidation of n-3 and n-6 polyunsaturated fatty acids (PUFA), were observed at <10-77 and 41-132 microg kg(-1) in the infant formulas (n = 12) and at <10-52 and 36-116 microg kg(-1) in the baby foods (n = 7), respectively. 4-Hydroxy-2-alkenals in infant formulas and baby foods were further determined at 10 and 30 days after opening in an attempt to examine the time dependence of the levels of 4-hydroxy-2-alkenals. The values of HHE and HNE had increased appreciably to <10-220 and 79-792 microg kg(-1) in infant formulas and to <10-112 and 135-572 microg kg(-1) in baby foods, respectively, at 10 days and decreased, although statistically not significant, in most of the tested samples after 30 days, which suggested that the reactive compounds might interact with other constituents like proteins in the samples to form adducts or be decomposed with time. Based on the current study, it was calculated that 3-month to 1-year-old babies maintained exclusively on these commercially available PUFA-fortified infant formulas or baby foods could be exposed to a maximum of 20.2 microg kg(-1) body weight day(-1) of 4-hydroxy-2-alkenals, which is two orders of magnitude higher than the exposure of Korean adults estimated in a previous study of the authors' (2005). The present study may trigger future studies investigating the physiological influence of 4-hydroxy-2-alkenals originating from the diet on man at an early stage of development.     

Evaluation of aluminium concentrations in samples of chocolate and beverages by electrothermal atomic absorption spectrometry

Samples of chocolate, cocoa, tea infusions, soft drinks and fruit juice have been examined by, electrothermal atomic absorption spectrometry (ETA-AAS) for the presence of aluminium (Al). Fruit juices and chocolate were analysed after an adequate sample preparation; the other products were evaluated directly. Sampling was performed in duplicate for 248 independent samples. The mean Al concentration in chocolate was 9.2 +/- 7.5 mg kg(-1), and individual values were correlated with the per cent of cocoa in samples (Y = 0.63 + 0.27X, r = 0.78, p < 0.0001). Al concentration in commercial tea infusions ranged from 0.9 to 3.3 mg l(-1) (mean = 1.80 +/- 65 mg l(-1), whereas in laboratory-prepared samples it was 2.7 +/- 0.93 mg l(-1). In soft drinks, the concentrations of Al were lower, ranging from 9.1 to 179 microg l(-1); the highest values were observed in samples of orange squash (mean = 114 +/- 56 microg l(-1)). Apricot juice showed the highest Al level (mean = 602 +/- 190 microg l(-1)), being statistically, different from that of pear (mean = 259 +/- 102 microg l(-1)), but not different from that of peach juice (mean = 486 +/- 269 microg kg(-1)). Toxicologically, the amount of Al deriving from the consumption of these products is far below the acceptable daily intake of 1 mg kg(-1) body weight indicated by the FAO/WHO, and it is a verv low percentage of the normal Al dietary intake.     

Fusarium toxins in wheat from an area in Henan Province, PR China, with a previous human red mould intoxication episode.

Wheat samples of the 1998 and 1999 crops from Puyang, an area in Henan Province, PR China with a previous human red mould intoxication episode, were analysed for trichothecenes and zearalenone (ZEA). For the 1998 Puyang crop, deoxynivalenol (DON) was the predominant toxin detected abundantly and frequently at a level of up to 14,000 microg kg(-1) (mean 2850 microgkg(-1)) in 30 of 31 (97%) wheat samples. Among these were 21 (70%) with a DON level that exceeded the Chinese regulation of 1,000 microg kg(-1). Nivalenol (NIV) and 15-acetyl-DON (15-ADON) were also found at 578 microg kg(-1) (one sample) and 59-1,800 microg kg(-1) (mean 365 microg kg(-1), 20 samples), respectively. ZEA co-occurred in 21 samples at 9-1,400 microg kg(-1) (mean 209 microg kg(-1)). Twenty-five (89%) wheat samples from Zhumadian, a region without a history of human red mould intoxication in the same province, contained low levels of DON (53-1240, mean 223 microg kg(-1)) with seven (25%) co-contaminated with ZEA (10-217, mean 108 microg kg(-1)). All were free from 15-ADON and NIV. Significant differences in DON, 15-ADON and ZEA concentrations between both areas were found. DON (<1000 microg kg(-1)) and ZEA (5-111 microg kg(-1)) were also detected in the 1999 Puyang wheat. Proper environmental conditions for Fusarium species surviving winter combined with unusual high precipitation during wheat flowering were responsible for a high concentration of Fusarium mycotoxins in the 1998 Puyang wheat.     

Incidence of trichothecenes and zearalenone in poultry feed mixtures from Slovakia

A total of 50 samples of poultry feed mixtures of Slovakian origin were analyzed for eight toxicologically significant Fusarium mycotoxins, namely zearalenone (ZON), A-trichothecenes: diacetoxyscirpenol (DAS), T-2 toxin (T-2) and HT-2 toxin (HT-2) and B-trichothecenes: deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl-deoxynivalenol (15-ADON) and nivalenol (NIV). The A-trichothecenes and the B-trichothecenes were detected by means of high pressure liquid chromatography with tandem mass spectrometry detection (HPLC-MS/MS) and gas chromatography electron capture detection (GC-ECD), respectively. Reversed phase-high performance liquid chromatography with a fluorescence detector (RP-HPLC-FLD) was used for ZON detection. The most frequent mycotoxin detected was T-2, which was found in 45 samples (90%) in relatively low concentrations ranging from 1 to 130 microg kg(-1) (average 13 microg kg(-1)), followed by ZON that was found in 44 samples (88%) in concentrations ranging from 3 to 86 microg kg(-1) (average 21 microg kg(-1)). HT-2 and DON were detected in 38 (76%) and 28 (56%) samples, respectively, in concentrations of 2 to 173 (average 18 microg kg(-1)) for HT-2 and 64 to 1230 microg kg(-1) sample (average 303 microg kg(-1)) for DON. The acetyl-derivatives of DON were in just four samples, while NIV was not detected in any of the samples investigated. In as many as 22 samples (44%), a combination of four simultaneously co-occurring mycotoxins, i.e. T-2, HT-2, ZON and DON, was revealed. Despite the limited number of samples investigated during this study poultry feed mixtures may represent a risk from a toxicological point of view and should be regarded as a potential source of the Fusarium mycotoxins in Central Europe. This is the first reported study dealing with zearalenone and trichothecene contamination of poultry mixed feeds from Slovakia.     

Ochratoxin A in conventional and organic cereal derivatives: a survey of the Italian market, 2001-02.

Ochratoxin A is a mycotoxin produced mainly by Penicillium verrucosum and Aspergillus ochraceus. Although typically considered a cereal contaminant, it has also been detected in dried fruit, nuts, meat and derivatives. To estimate the quantity of ochratoxin A that might be ingested by Italian consumers from these foods, 211 cereal derivatives (flours and bakery products) were analysed by high-performance liquid chromatography. Products were from conventional and organic agriculture and from integrated pest management agriculture. All commercial flours and derivatives examined contained ochratoxin A at concentrations very much below the legal limit (3 microg kg(-1)): the highest value, 0.816 microg kg(-1), was detected in a sample of spelt whole flour from organic agriculture. In many samples, the ochratoxin content was below the limit of detection; only rarely did values exceed 0.5 microg kg(-1). In baby foods, four samples were above the particularly restrictive Italian legal limit of 0.5 microg kg(-1). Although some significant differences were found between samples from conventional and organic agriculture when some product categories were examined (namely, baby foods as semolina and rice creams), no important difference was found between the two types of agricultural practice when all types of cereal derivatives were considered together.     

Occurrence of patulin in conventional and organic fruit products in Italy and subsequent exposure assessment.

The occurrence of patulin was investigated in 100 conventional and 69 organic fruity foodstuffs samples commercially available in Italy by using an HPLC method with a limit of quantification of 0.5 microg kg(-1). Patulin was detected in 26 (26%) conventional and 31 (45%) organic products with a significantly higher (p<0.01) mean concentration in the organic products (4.78 vs. 1.15 microg kg(-1)). Mean patulin concentrations in conventional apple juices, pear juices, other juices and fruits purees were 3.14, 0.22, 0.19, 0.11 microg kg(-1), respectively, and 7.11, 11.46, 2.10, 0.18 microg kg(-1) in the relevant organic products. Four samples of juices (one conventional and two organic apple, and one organic pear) contained patulin at concentrations above the limit of 50 microg kg(-1), four at concentrations between 10 and 25 microg kg(-1), and the remaining ones below 10 microg kg(-1). Patulin was detected (<1 microg kg(-1)) in only three of the 23 fruity baby food samples tested (homogenized fruits, 11 conventional and 12 organic). Based on the available data on Italian intakes of fruit juices, the estimated daily intakes of patulin, were 0.38 and 1.57 ng kg(-1) body weight (bw) from conventional and organic products, respectively. Estimated daily intakes of patulin for children were higher, 3.41 ng kg(-1) bw from conventional and 14.17 ng kg(-1) bw from organic products, but largely below the provisional maximum tolerable daily intake (PMTDI) of 400 ng kg(-1) bw. Patulin was also found in two samples of organic apple vinegar (<5 microg kg(-1)) and in fresh apples with rotten spots (12 out of 24 samples) with maximum levels at 16,402 and 44,572 microg kg(-1) for conventional and organic apples, respectively.     

Spatial distribution of natural enrichments of arsenic, selenium, and uranium in a minerotrophic peatland, Gola di Lago, Canton Ticino, Switzerland

Gola di Lago is a small (ca. 3 ha), minerotrophic peatland in Canton Ticino, southern Switzerland. Chemical analyses of peat show remarkable concentrations of As, Se, and U. Coring at regular intervals (19 sites) revealed several zones of pronounced accumulation, with As concentrations up to 350 mg kg(-1) (2000 mg kg(-1) on a mineral matter basis). Both Fe and S are also enriched at this depth, suggesting that redox-related transformations have affected all three elements. High concentrations of Se (up to 28 mg kg(-1)) and U (up to 470 mg kg(-1)) were also detected, representing on a mineral matter basis 350 and 2900 mg kg(-1), respectively. An intermittent stream entering the peatland contained up to 400 microg of As L(-1), but the permanent stream leaving the mire contains <2 microg L(-1). A three-dimensional map of the spatial distribution of As shows that the main source of As is the intermittent stream and not the basal, mineral sediment underlying the peatland. Arsenic is highly enriched not only in shallow peat layers at the interface between the stream and peatland today but also in deeper peat layers in the center of the mire, at what must have been the stream-peat interface in the past. By sequential extraction of fresh peat samples, 100% of the As could be extracted from a shallow sample but only 19% from a sample taken from the deeper layers. In both cases, most of the As was associated with the organic matter fraction (73% and 57% respectively). Although this peatland is an effective geochemical trap for As in the stream waters, the mechanisms of removal remain unclear.     

The presence of Penicillium and Penicillium mycotoxins in food wastes

A total of 97 samples (48 summer and 49 winter) of food waste from private households were investigated for Penicillium and for mycotoxins. Twenty-five Penicillium species were isolated and Penicillium crustosum, Penicillium brevicompactum, Penicillium chrysogenum, Penicillium expansum, Penicillium roqueforti, Penicillium spinulosum, Penicillium viridicatum, Penicillium commune, Penicillium citrinum and Penicillium solitum were, in decreasing order, the most frequently identified species. Mycotoxins produced by several of these species, including mycophenolic acid, roquefortine C, penitrems A-F and thomitrems A and E, were detected. Of the 48 summer samples, 36 were severely infected and contained more than 10(5) colony forming units (CFU) Penicillium/g sample. The levels of mycotoxins in these samples were in the range 75-19000 microg/kg mycophenolic acid, 40-920 microg/kg roquefortine C, 35-7500 microg/kg penitrem A, 20-2100 microg/kg thomitrem A and 20-3300 microg/kg thomitrem E. Of the 49 winter samples, only one was found to contain mycophenolic acid (4800 microg/kg) and roquefortine C (190 microg/kg), and this sample was severely infected with P. roqueforti. Thirty samples of food waste collected from the food manufacturing industry were also investigated. The number of Penicillium in these samples was between 10(5) and 10(6) colony forming units (CFU)/g sample. Seven of these samples contained mycophenolic acid ranging from 50 to 600 microg/kg and three of these samples also contained roquefortine C in the range 100-250 microg/kg.     

Brominated and chlorinated dioxins, PCBs and brominated flame retardants in Scottish shellfish: methodology, occurrence and human dietary exposure

The most commonly consumed shellfish species produced in Scotland - mussels, oysters and scallops - were investigated for the occurrence of a range of brominated and chlorinated contaminants in order to establish current levels and estimate human dietary exposure. Flesh from individual sub-samples was representatively pooled and 35 composites were analysed for brominated and chlorinated dioxins (PBDD/Fs, PCDD/Fs), brominated and chlorinated biphenyls (PBBs, PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs) and tetrabromobisphenol A (TBBPA). The analytical methodology used (13)C(12) labelled surrogates of the target compounds, with GC coupled to (usually) high resolution MS, and LC-MS/MS for HBCD and TBBPA analysis. Positive identifications were made in the majority of samples for most analytes with the exception of TBBPA and most PBDD congeners measured. None of the levels detected for PCDD/F and PCB were above the maximum permitted levels specified in European Union regulations. The levels of brominated furans predominated over brominated dioxins, reflecting the environmental distribution and source emission profiles of these contaminants, and relatively high levels of the tri-brominated congeners were observed. Levels of the flame retardant chemicals reflected current and legacy use, with appreciable concentrations of PBDEs and HBCDs (predominantly alpha-HBCD) but far lower levels of PBBs. TBBPA was not detected in any of the species. In general, mussels and oysters displayed relatively higher levels of contamination than scallops, although the gonad tissue of the latter showed significant levels of brominated dioxins. The estimated adult dietary intakes of PCDD/Fs and PCBs arising from the consumption of a typical portion of these foods in combination with an otherwise average UK diet were in the range 0.5-0.6 pg World Health Organisation (WHO)-toxic equivalent (TEQ)(2005)/kg bodyweight per day. These estimated dietary intakes are well within the Tolerable Daily Intake for dioxins and dioxin-like PCBs of 2 pg WHO-TEQ(2005)/kg bodyweight/day endorsed by the independent expert Committee on Toxicology of Chemicals in Food, Consumer Products and the Environment. The corresponding intakes for sumPBDEs and sumHBCDs were 5.6-6.1 and 5.9-7.9 ng/kg bodyweight/day respectively.     

Fate of ivermectin residues in ewes' milk and derived products

The fate of ivermectin (IVM) residues was studied throughout the processing of daily bulk milk from 30 ewes (taken up to 33 d following subcutaneous administration of 0.2 mg IVM/kg b.w.) in the following milk products: yoghurt made from raw and pasteurized milk; cheese after pressing; 30- and 60-day ripened cheese; and whey, secondary whey and whey proteins obtained after cheese-making (albumin cheese). The concentration of the H2B1a component of IVM was analysed in these dairy products using an HPLC method with fluorescence detection. The mean recovery of the method was, depending on the matrix, between 87 and 100%. Limits of detection in the order of only 0.1 microg H2B1a/kg of product were achieved. Maximum concentrations of IVM were detected mostly at 2 d after drug administration to the ewes. The highest concentration of IVM was found on day 2 in 60-day ripened cheese (96 microg H2B1a/kg cheese). Secondary whey was the matrix with the lowest concentration of IVM (<0.6 microg H2B1a/ kg). Residue levels fell below the limits of detection between day 5 (for secondary whey) and day 25 (for all cheese samples). In the matrices investigated, linear correlations between daily concentrations of IVM, milk fat and solid content were evident. During yoghurt production, fermentation and thermal stability of IVM was observed. During cheese production, approximately 35% of the IVM, present in the raw (bulk) milk samples, was lost. From the results it was concluded that the processing of ewes' milk did not eliminate the drug residues under investigation. The consequences of IVM in the human diet were discussed. Milk from treated animals should be excluded from production of fat products like cheese for longer after treatment with IVM than for lower fat products.     

The correspondence between U.K. 'action levels' for lead in blood and in water

This paper considers whether the Department of the Environment's water lead concentration criterion for lead pipe replacement and action in individual cases, i.e. 50 micrograms/l in any sample, is too high when set against the Department of Health's advisory action limit for blood lead concentration of 25 micrograms/100 ml. The relationships between blood lead and water lead concentrations found in the Glasgow and Ayr duplicate diet studies, together with unpublished data from Glasgow and Liverpool, indicate that over 10% of people exposed to an average water lead concentration of 100 micrograms/l (the earlier action level) would have blood lead concentrations above 25 micrograms/100 ml, as would about 4% of those exposed to 50 micrograms/l (the Maximum Admissible Concentration in an EEC Directive). For adults, average water lead concentrations should not exceed 30 micrograms/l to ensure compliance with the limit for blood lead, i.e. so that not more than 2% exceed 25 micrograms/100 ml. However, for one of the critical groups, bottle-fed infants (whose diet is 90% water), average water lead concentrations should not exceed 10-15 micrograms/l. The WHO's Provisional Tolerable Weekly Intake (PTWI) for children (25 micrograms/kg body weight) also implies that their water lead concentrations should not exceed 10-15 micrograms/l.     

Geographical distribution (2000) and temporal trends (1981-2000) of brominated diphenyl ethers in Great Lakes hewing gull eggs

Geographical distribution of brominated diphenyl ether (BDE) flame retardants in the North American Great Lakes ecosystem in 2000 was determined by analysis of herring gull eggs (13 egg pools) from a network of 15 monitoring colonies scattered throughout the lakes and connecting channels. sigmaBDEs were found at concentrations ranging from 192 to 1,400 microg/kg, mean of 662 +/- 368 microg/kg (wet weight of egg contents). Highest concentrations were found in northern Lake Michigan and Toronto harbor (1,000-1,400 microg/kg) and lowest in Lake Huron and Lake Erie (192-340 microg/kg). The distribution suggested that input from large urban/ industrial areas through air or water emissions contributes local contamination to the herring gull food web in addition to background levels from regional/global transport. The congener composition was similar among sampling sites. Major congeners were BDE-47 (43%), BDE-99 (26%), BDE-100 (13%) BDE-153 (11%), BDE-154 (4%), BDE-183 (2%) and BDE-28 (1%). Temporal trends of BDE contamination, 1981-2000, were established by analysis of archived herring gull eggs (10 egg pools) from colonies in northern Lake Michigan, Saginaw Bay, Lake Huron and eastern Lake Ontario. BDE-47, -99 and -100, and BDE-153, -154 and -183 concentrations were grouped separately for analysis because these two groups had different trends and are primarily associated with the Penta BDE and Octa BDE flame retardant formulations, respectively. SigmaBDE47,99,100 concentrations were 5-12 microg/kg (wet weight) in 1981-1983 and then increased exponentially (p < 0.00001) at all three sites to 400-1,100 microg/kg over the next 17 years. Doubling times were 2.6 years in Lake Michigan, 3.1 years in Lake Huron and 2.8 years in Lake Ontario. SigmaBDE154,153,183 concentrations generally increased but varied in an erratic fashion among sites and decreased as a fraction of sigmaBDE over time. Concentrations of sigmaBDE154,153,183 were 100-200 microg/kg in eggs from all three colonies in 2000. Therefore, most of the dramatic increases in sigmaBDE concentrations observed over the past 20 years in the Great Lakes aquatic ecosystem seem to be connected with the Penta BDE formulation, which is mainly used as a flame retardant in polyurethane foam in North America. If present rates of change continue, concentrations of sigmaBDEs will equal or surpass those of sigmaPCBs in Great Lakes herring gull eggs in 10-15 years.     

Occurrence of aflatoxin in commodities imported into Qatar, 1997-2000.

The occurrence of aflatoxin in commodities imported into Qatar was investigated from 1999 to 2000. During the 4 years, 351 samples of susceptible commodities were analysed. Aflatoxin was detected in 71 (20%) samples in the range 0.1-20 microg kg(-1) and in 50 (14%) samples above the permitted level of 20 microg kg(-1). The highest incidence and levels of aflatoxin contamination were recorded in pistachio without shell followed by pistachio with shell. Aflatoxin levels >20 microg kg(-1) in the pistachio samples varied from 8.7 to 33%. The highest level of total aflatoxin found in pistachio without shell was 289 microg kg(-1). A few samples of corn and corn products (three of 54 analysed), peanut and peanut products (nine of 42 analysed) and other nuts like almond, walnut and cashew (one of 40 analysed) were found contaminated with low levels (0.1-20 microg kg(-1)) of aflatoxins. Only one sample of custard powder and one sample of roasted peanut were found with aflatoxin >20 microg kg(-1)     

Estimation of chromium bioavailability from the diet by an in vitro method.

An in vitro method was used to study the dialysable fraction of chromium (Cr) from the diet which simulates human gastric and intestinal digestion. The percentage of dialysed Cr was used to assess the bioavailability. The duplicate diet approach was used to obtain ten different sets of samples each representative of the normal diet consumed in southern Spain. In each case triplicate analysis of Cr was carried out by electrothermal atomization-atomic absorption spectrometry in acid-mineralized samples. The Cr dietary intake ranged from 16 to 117 microg/day, and the dialysable Cr fraction ranged from 0.4% to 1.6%. The Cr absorption was higher for low levels of daily dietary intake of Cr (< 40 microg) than for levels of 40-80 microg; for high levels (> 80 microg) there was an increase in the dialysable fraction. The energy and nutrient intake of these diets was also evaluated.     

Photochemistry of 4-chlorophenol on cellulose and silica

The photochemistry of 4-chlorophenol (4-CP) was studied on silica and cellulose, using time-resolved diffuse reflectance techniques and product degradation analysis. The results have shown that the photochemistry of 4-CP depends on the support, on the concentration, and also on the sample preparation method. Transient absorption and photoproduct results can be understood by assuming the formation of the carbene 4-oxocyclohexa-2,5-dienylidene in both supports. On cellulose, at concentrations lower than 10 micromol g(-1), the carbene leads to the unsubstituted phenoxyl radical, and phenol is the main degradation product. At higher concentrations a new transient resulting from phenoxyl radicals coupling was also observed, and dihydroxybiphenyls are also formed. The reaction of the carbene with ground-state 4-CP was also detected through the formation of 5-chloro-2,4'-dihydroxybiphenyl. 4-Chlorophenoxyl radical and degradations products resulting from its coupling were also detected. Oxygen has little effect on the photochemistry of 4-CP on cellulose. On silica the transient benzoquinone O-oxide was formed in the presence of oxygen. Benzoquinone and hydroquinone are the main degradation products. In well-dried samples the formation of hydroquinone is reduced. At higher concentrations the same products as detected on cellulose were observed. 4-CP undergoes slow photochemical decomposition under solar radiation in both supports. The same main degradation products were observed in these conditions.     

Ochratoxin A in raisins and currants: basic extraction procedure used in two small marketing surveys of the occurrence and control of the heterogeneity of the toxins in samples.

A basic extraction procedure for analysis of ochratoxin A (OTA) in currants and raisins is described, as well as the occurrence of OTA and a control of heterogeneity of the toxin in samples bought for two small marketing surveys 1999/2000 and 2001/02. Most samples in the surveys were divided into two subsamples that were individually prepared as slurries and analysed separately. The limit of quantification for the method was estimated as 0.1 microg kg(-1) and recoveries of 85, 90 and 115% were achieved in recovery experiments at 10, 5 and 0.1 microg kg(-1), respectively. Of all 118 subsamples analysed in the surveys, 96 (84%) contained ochratoxin A at levels above the quantification level and five samples (4%) contained more than the European Community legislation of 10 microg kg(-1). The OTA concentrations found in the first survey were in the range < 0.1-19.0 microg kg(-1) with a median concentration of 0.9 microg kg(-1). In the 2001/02 study, the range was < 0.1-34.6 microg kg(-1) with a median of 0.2 microg kg(-1). Big differences were often achieved between individual subsamples of the original sample, which indicate a wide heterogeneous distribution of the toxin. Data from the repeatability test as well as recovery experiments from the same slurries showed that preparation of slurries as described here seemed to give a homogeneous and representative sample. The extraction with the basic sodium bicarbonate-methanol mixture used in the surveys gave similar or somewhat higher OTA values on some samples tested in a comparison with a weak phosphoric acid water-methanol extraction mixture.     

Levels of the flame retardants hexabromocyclododecane and tetrabromobisphenol A in the blubber of harbor porpoises (Phocoena phocoena) stranded or bycaught in the U.K., with evidence for an increase in HBCD concentrations in recent years

Within the U.K. Marine Mammals Stranding Program, analysis of brominated flame retardants began in 1999. Initially, the focus of attention was the brominated diphenyl ethers. Since the withdrawal of the pentamix and octamix polybrominated diphenyl ether (PBDE) formulations from the EU market prior to August 2004, two other high-volume products, hexabromocyclododecane (HBCO) and tetrabromobisphenol A (TBBP-A), have been included. We report the concentrations of these compounds in the blubber of harbor porpoises (Phocoena phocoena) stranded or dying due to physical trauma in the U.K. during the period 1994-2003. Analysis was undertaken using LC/MS method on a diastereoisomer basis. Eighty-five samples were analyzed for HBCD, and 68 of these for TBBP-A. alpha-HBCD dominated over the other isomers and was detected in all samples analyzed at concentrations ranging from 10 to 19 200 microg kg(-1) wet weight. The maximum concentration was about double that reported in earlier U.K. studies. TBBP-A was detected in only 18 samples and at much lower concentrations, from 6 to 35 microg kg(-1) wet weight. Investigation of possible time trends indicated a sharp increase in HBCD concentrations from about 2001 onward, which was not confounded by age (length), sex, nutritional status, or location. This may be a result of changing patterns of use of HBCD following limitations on the production and use of two PBDE formulations within the EU and will feed ongoing risk assessment activities.