Tolerable Daily Intake Level Research Articles

Regulating the Use of Bisphenol A in Baby and Children's Products in the European Union: Current Developments and Scenarios for the Regulatory Future

Parents of newborns and small children have recently been confronted with labels indicating that their purchases of a baby bottle, teethers or sippy cups are now ‘Bisphenol A-free’ (BPA). A synthetic chemical used in the production process of polycarbonate (plastics), Bisphenol A is currently making headline news in the US and the EU. Its questioned safety in food plastics, baby bottles and children's toys has turned plastics into a political issue as it is systematically framed as a risk in media coverage.Apart from regulatory exposure limits (Tolerable Daily Intake levels (TDI), Bisphenol A is currently not subject to any restrictions in use yet (although BPA will be subject to a ban on the EU level from spring 2011 onwards). However, with the REACH framework (Registration, Evaluation, Authorisation of Chemicals), a new regulatory framework for EU's chemical policy in place since June 2007, these exposure limits may be reviewed and BPA may face regulatory action. This article aims to analyse the regulatory process of Bisphenol A in the EU as an example of an uncertain risk dossier. On the basis of document and media analysis and interviews, the main aim is to gain an understanding of how uncertain risks are being regulated in the European Union. To that end, the self-regulatory behavior of industry is also considered. On the basis of the current regulatory tools in place and the current state of affairs, as well as developments in the controversy around BPA, the paper concludes by presenting four scenarios that illustrate the dynamics of the case and its possible regulatory outcomes.

A hierarchical Bayesian approach for risk assessment of melamine in infant formula based on cases of related nephrolithiasis in children

Although the 2008 outbreak of nephrolithiasis in children due to melamine-contaminated infant formula has subsided, it remains uncertain whether the present tolerable daily intake (TDI) of melamine provides sufficient protection for young children. To conduct a safety assessment for melamine in infant formula, we established a dose–response relationship based on 13 nephrolithiasis cases selected from 932 children, all of whom were under 5 years of age and had potentially been exposed to contaminated milk in China or Taiwan. According to the children's exposure history, distributions of individual daily melamine intake (mg/kg BW/day) were reconstructed using Monte Carlo simulations to account for uncertainties in exposure duration and melamine concentrations in the contaminated milk. Based on the simulated individual average daily intake (AVDI) of melamine, subjects were further classified into four separate AVDI groups: high, medium, low and a reference group. A statistical logistic model was then fitted for the dose–response relationship between nephrolithiasis incidence and daily melamine intakes using Markov chain Monte Carlo (MCMC) simulations. Based on the background exposure, spontaneous rate, and mode of action (MOA) of nephrolithiasis in children, the simulated lower bounds of the 95% CIs daily melamine intake ranged from 0.008 to 0.03 mg/kg BW/day corresponding to an additional risks of 0.1% is proposed as a plausible TDI, which is approximately an order lower than the current WHO-suggested TDI level of 0.2 mg/kg BW/day. More stringent regulations on melamine levels in infant formula should be considered to protect young children fully.

Bioaccumulation of cyanuric acid in edible tissues of shrimp following experimental feeding

Due to concerns that cyanuric acid (CYA)-contaminated feed had been used in aquaculture and could enter the human food chain, a method to quantify CYA residues in the edible tissues of fish and shrimp was previously developed and validated. This paper provides further data on the deliberate feeding of CYA to shrimp to determine the extent of residue accumulation in edible tissue. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) was employed for the analysis of CYA in shrimp tissue. Edible tissue of shrimp fed 1666 or 3333 mg kg−1 CYA in their diet (approximately 55 and 124 mg kg−1 body weight) contained 0.767 and 0.406 mg kg−1 CYA, respectively. The residue levels are below the World Health Organization (WHO) tolerable daily intake level for CYA and are generally considered unlikely to pose a human health risk.

Dioxins (PCDD/Fs) and PCBs in offal: Occurrence and dietary exposure

Offals are widely consumed in different cuisines, but information on the occurrence of dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in these foods is sparse. In the first structured investigation of its kind, this study reports levels of these contaminants in commonly consumed offals ( n = 173) such as lamb, ox, deer and pig’s liver, kidneys, tongue and heart, and offal products such as pâté, haggis, tripe and black pudding. The results support literature observations on the preferential accumulation of contaminants in liver tissue, as the highest concentrations of PCDD/Fs were observed in liver, relative to the other organs (e.g. 8.4 ng WHO-TEQ kg −1 lamb liver compared to 1.1 ng WHO-TEQ kg −1 lamb kidney and 1.27 ng WHO-TEQ kg −1 lamb heart). Offal products generally showed lower contaminant levels which may be a result of processing or dilution. For most samples, the main contribution to WHO-TEQ arose from PCDD/Fs rather than PCBs. Just under half of the lamb liver samples showed PCDD/F concentrations that exceeded the EU maximum limit of 6 ng kg −1 fat weight (although deer liver which is not subject to the regulation, generally showed higher levels). Dietary exposure estimates indicate that the weekly consumption of up to two 100 g portions of lamb, ox, calf or pig liver or one portion of deer liver would not breach the tolerable daily intake (TDI) level even when the rest of the diet was included. However, the consumption of more than one portion of deer liver per week may lead to the TDI being exceeded.

Perinatal Exposure to Bisphenol A Affects Sexual Differentiation of Behaviors in Offspring Mice

Bisphenol A (BPA) is one of the well-known environmental endocrine disrupters with mixed estrogen agonist/antagonist properties. Although many studies have focused on the toxicity to the reproductive system and development,less on the central nervous system. Published results have demonstrated that perinatal exposure to low doses of BPA (below the human tolerable daily intake level,0.05 mg/kg/day) does not affect reproductive system,but affects sexual behavior,social behavior,and other neurobehaviors. The purpose of this study was to investigate whether perinatal maternal exposure to BPA affects sexual differentiation of behaviors in offspring mice. After acclimatization for one week,adult female ICR mice were placed with males (two females:one male) and vaginal smears were examined daily. A sperm-positive smear determined gestational day (GD) 0. After detection,pregnant dams were orally exposed to BPA dissolved in peanut oil (50,5,0.5 or 0.05 mg/kg/day) or only peanut oil as a vehicle control from gestational day(GD) 7 through postnatal day (PND) 21. At PND 21 and PND 56 of age,open field,elevated plus-maze,Morris water maze,and step down were respectively used to test spontaneous activity and exploratory behavior,anxiety,spatial learning and memory,and passive avoidance memory in offspring mice. The results showed that perinatal exposure to BPA significantly inhibited the growth of body weight of male and female offspring (p 0.001). The results from open field showed that BPA decreased the spontaneous activity of male offspring on PND21 and PND 56 and female offspring on PND 21(p 0.05 or p 0.01),increased grooming and rearing in male but decreased grooming and rearing in female offspring on PND 21(p0.05 or p 0.01). The results from elevated plus-maze displayed that,after perinatal exposure to BPA,the frequency of open arms entrance and stayed time in the open arms were dose-independently increased,but stayed time in the closed arm was dose-independently decreased in the PND 21 male and female and the PND 56 female offspring(p 0.05 or p 0.01); however,the influence of BPA on the behaviors of male and female offspring on PND 56 was different,with increased entrance of the open arms and decreased entrance of the closed arm in female,and decreased entrance of the open arm and increased entrance of the closed arm in male offspring. The results of Morris water maze test showed that BPA dose-dependently increased the distances to find the platform in the water maze of PND 21 and PND56 male,especially under the dose of 5～50 mg/kg/day(p 0.05 or p 0.01),but no significant influence was found in the female mice. In addition,in the step down test,5～50 mg/kg/day BPA increased the frequency of error and reduced the latency of stepping down from the platform in PND 21 male; and 50 mg/kg/day BPA increased the frequency of error and reduced the latency of stepping down from the platform in PND 56 male and female offspring. These results suggest that perinatal maternal exposure to BPA affects sexual differentiation of behaviors during the puberty and adulthood of offspring mice. The spontaneous activity and exploratory behavior,spatial learning and memory,and passive avoidance memory in male offspring are more sensitive,while anxiety in female offspring is more sensitive to perinatal exposure to BPA.

Determination of seasonal variations in serum ochratoxin A levels in healthy population living in some regions of Turkey by enzyme-linked immunosorbent assay

This study has been undertaken to investigate the regional and seasonal variability in ochratoxin A (OTA) exposure of healthy population living in Black Sea and Mediterranean regions of Turkey by measuring serum OTA concentrations. The mean serum concentrations of OTA were determined to be 0.137 ng/mL (0.0306-0.887 ng/mL) and 0.312 ng/mL (0.028-1.496 ng/mL) in all samples for winter and summer, respectively by enzyme-linked immunosorbent assay (ELISA). The differences between mean values of OTA in all serum samples collected in summer and winter were statistically significant. The highest OTA concentration was determined in the children living in Black Sea Region in summer. The mean daily intake levels of OTA in all samples were estimated as 0.182 ng/kg b.w./day and 0.408 ng/kg b.w./day in winter and summer, respectively. The results showed that the mean serum concentrations of OTA in healthy population in both regions were found not to be exceeded 1 ng/mL in agreement with the distribution reported in most European countries and that the daily intake levels of OTA were calculated below the tolerable daily intake levels given by regulatory authorities. However, overall results suggest that Turkish population living in these regions is continuously exposed to OTA and that the exposure levels are also elevated in summer period compared to winter.

Toxicity value for 3-monochloropropane-1,2-diol using a benchmark dose methodology

3-Monochloropropane-1,2-diol (α-chlorohydrin, 3-MCPD) is a well-known contaminant that has been detected in a wide range of foods, and that is principally generated in foods prepared by hydrochloric acid hydrolysis, such as acid-hydrolyzed vegetable protein (acid-HVP). 3-MCPD is nephrotoxic to animals at high doses and induced tumors in some organs in both sexes of rodents. NITR have recently reported on the carcinogenicity of 3-MCPD in SD rats that were exposed for 2 years to drinking water. We considered that the kidney was the main target organ for 3-MCPD in SD rats and that renal tubular hyperplasia was the most sensitive endpoint. Benchmark dose analysis of the dose–response data for renal tubular hyperplasia in male and female rats exposed to 3-MCPD in drinking water for 2 years was conducted. We applied this to the benchmark dose (BMD) methodology to yield a point of departure for developing tolerable daily intakes (TDIs). The calculated BMDs and lower-bound confidence limits (BMDLs) for the critical endpoint were estimated using the seven different models. Predicted doses associated with 10% extra risk were calculated. The smallest Akaike’s Information Criterion (AIC) was used in selecting the appropriate model. The model chosen by AIC for males was the logistic and for females it was the multistage. In summary, the predicted BMD 10 and BMDL 10 were 1.21 mg/kg bw/day and 0.87 mg/kg bw/day for the male rat incidence data, and values for female rats were 26.31 mg/kg bw/day and 19.47 mg/kg bw/day. In this study, the BMDL 10 of 0.87 mg/kg bw/day for male rats was suggested as the point of departure for deriving the human tolerable daily intake level of 3-MCPD.

Mercury and other trace elements in farmed and wild salmon from british Columbia, Canada

AbstractThe present study reports measured levels of Hg and other trace elements in commercial salmon feed; farmed Atlantic, coho, and chinook salmon (n = 110); and wild coho, chinook, chum, sockeye, and pink salmon (n = 91). Metal concentrations in farmed and wild salmon from British Columbia, Canada, were relatively low and below human health consumption guidelines. Methylmercury in all salmon samples (range, 0.03–0.1 μg/g wet wt) were below the 0.5 μg/g guideline set by Health Canada. Negligible differences in metal concentrations were observed between the various species of farmed and wild salmon. Metal concentrations generally were higher in commercial salmon feed compared to farmed salmon. Mercury showed slight bioaccumulation potential in farmed salmon, with biomagnification factors (BMFs) ranging between 0.8 and 1.9. Other metals, such as Cd, Pb, and Ni, exhibited biodilution, with BMFs of much less than one. The relatively low degree of biomagnification of metals observed in farmed salmon likely resulted from the combination of low gastrointestinal absorption efficiency, negligible transfer to muscle tissue relative to other compartments, and a high degree of growth dilution in these fish. Human dietary exposure calculations indicate intakes of Hg, Cd, Pb, Cu, As, and Ni via farmed and wild British Columbia salmon are a relatively small percentage of total intakes (0.05–32%) compared to other Canadian foodstuffs, such as fruits, vegetables, chicken, and beef (68–99%). Although total dietary exposure of Cd, Pb, and Cu approached provisional tolerable daily intake levels, the contribution from British Columbia salmon was less than 2%. Our findings indicate farmed and wild British Columbia salmon remain a safe source of omega‐3 highly unsaturated fatty acid intake for cardioprotective and, possibly, other health benefits.

어촌, 농촌, 도시 지역별 주민의 식품을 통한 다이옥신의 섭취량 추정

본 연구에서는 식생활 양상이 서로 다를 것으로 생각되는 어촌, 농촌, 도시 지역별 각각 213명, 193명, 187명을 대상으로 직접면담과 24시간 회상법에 의한 식사섭취조사를 실시한 후 35가지 식품 중 다이옥신 함량 자료를 이용하여 추정한 다이옥신 섭취상태를 비교·평가하였다. 지역별 조사대상자의 평균 연령은 어촌 61.5세, 농촌 57.6세, 도시 49.4세순으로 유의하게 높았으며, 신장은 도시 대상자가 160.0 ㎝로 어촌의 158.1 ㎝나 농촌의 157.7 ㎝보다 유의하게 높았다. 지역별 남녀 성별 분포는 유의한 차이가 없었다. 1일 에너지 섭취량은 농촌 1707.7 ㎉, 도시 1596.5 ㎉, 어촌 1493.8 ㎉로 농촌이 어촌보다 유의하게 높았다. 1일 총 식품섭취량은 지역별 유의한 차이가 없었으나 어패류는 어촌지역이, 곡류, 채소류, 육류, 조미료류는 농촌지역이, 당류, 두류, 난류, 해조류, 우유류, 유지류는 도시지역이 가장 높았다. 35종 식품의 다이옥신 함량자료를 이용하여 평가한 어촌, 농촌, 도시 대상자의 1일 다이옥신 섭취량은 어촌이 0.70 pgTEQ/㎏/day로 농촌의 0.32 pgTEQ/㎏/day나 도시의 0.46 pgTEQ/㎏/day보다 유의하게 높았다. 곡류, 두류, 채소류, 어패류를 통한 다이옥신 섭취량은 어촌이, 난류와 우유류를 통한 다이옥신 섭취량은 도시가 가장 높았다. 전체 대상자의 다이옥신 섭취량은 육류, 난류, 어패류, 유지류, 조미료류 및 총 식품섭취량과 각각 유의한 정의 상관관계를 보였다. 이상의 연구결과를 종합할 때 식품을 통한 다이옥신 섭취량은 어촌 지역이 농촌이나 도시보다 높고 어패류나 동물성식품을 통한 섭취가 높았으나, 세 지역 모두 우리나라 내용(耐容) 1일 섭취량보다 낮아 안전한 수준이었다.

Evaluation of organ distribution of microcystins in the freshwater phytoplanktivorous fish Hypophthalmichthys molitrix

To evaluate the public health risk of exposure to microcystins in fish food in China, the distribution pattern of microcystin-LR and microcystin-RR in various organs (liver, intestine, kidney, muscle and lipid) of the dominant freshwater phytoplanktivorous fish Hypophthalmichthys molitrix in Hangzhou, China's Tiesha River was investigated with the method of HPLC-ESI-MS analysis. The distribution of microcystins was different in the fish organs and the major total microcystins (microcystin-LR and microcystin-RR) were present in the intestines (6.49 micro g/g fresh weight), followed by the livers (4.52 micro g/g fresh weight) and the muscles (2.86 micro g/g fresh weight). Microcystins were detected in kidneys (1.35 micro g/g fresh weight), but not detected in lipid. The results suggested that the mean daily intake from fish was 0.03 micro g/kg body weight which was very close to the recommended WHO tolerable daily intake (TDI) level of 0.04 micro g/kg body weight per day, and local people were warned they may have health risk if they consumed fish from the river.

MERCURY AND OTHER TRACE ELEMENTS IN FARMED AND WILD SALMON FROM BRITISH COLUMBIA, CANADA

The present study reports measured levels of Hg and other trace elements in commercial salmon feed; farmed Atlantic, coho, and chinook salmon (n = 110); and wild coho, chinook, chum, sockeye, and pink salmon (n = 91). Metal concentrations in farmed and wild salmon from British Columbia, Canada, were relatively low and below human health consumption guidelines. Methylmercury in all salmon samples (range, 0.03-0.1 microg/g wet wt) were below the 0.5 microg/g guideline set by Health Canada. Negligible differences in metal concentrations were observed between the various species of farmed and wild salmon. Metal concentrations generally were higher in commercial salmon feed compared to farmed salmon. Mercury showed slight bioaccumulation potential in farmed salmon, with biomagnification factors (BMFs) ranging between 0.8 and 1.9. Other metals, such as Cd, Pb, and Ni, exhibited biodilution, with BMFs of much less than one. The relatively low degree of biomagnification of metals observed in farmed salmon likely resulted from the combination of low gastrointestinal absorption efficiency, negligible transfer to muscle tissue relative to other compartments, and a high degree of growth dilution in these fish. Human dietary exposure calculations indicate intakes of Hg, Cd, Pb, Cu, As, and Ni via farmed and wild British Columbia salmon are a relatively small percentage of total intakes (0.05-32%) compared to other Canadian foodstuffs, such as fruits, vegetables, chicken, and beef (68-99%). Although total dietary exposure of Cd, Pb, and Cu approached provisional tolerable daily intake levels, the contribution from British Columbia salmon was less than 2%. Our findings indicate farmed and wild British Columbia salmon remain a safe source of omega-3 highly unsaturated fatty acid intake for cardioprotective and, possibly, other health benefits.

In situ studies on the distribution patterns and dynamics of microcystins in a biomanipulation fish – bighead carp ( Aristichthys nobilis)

The distribution and dynamics of microcystins in various organs of the phytoplanktivorous bighead carp were studied monthly in Lake Taihu, which is dominated by toxic cyanobacteria. There was a good agreement between LC-MS and HPLC-UV determinations. Average recoveries of spiked fish samples were 63% for MC-RR and 71% for MC-LR. The highest MC contents in intestine, liver, kidney and spleen were 85.67, 2.83, 1.70 and 1.57 μg g −1 DW, respectively. MCs were much higher in mid-gut walls (1.22 μg g −1 DW) than in hind- and fore-gut walls (0.31 and 0.18 μg g −1 DW, respectively), suggesting the importance of mid-gut wall as major site for MC absorption. A cysteine conjugate of MC-LR was detected frequently in kidney. Among the muscle samples analyzed, 25% were above the provisional tolerable daily intake level by WHO. Bighead is strongly resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination in eutrophic waters.

Modelling Human Exposure of Methylmercury from Fish Consumption

Abstract Mercury and its compounds are widely distributed in the environment and the principal cause of methylmercury accumulation in humans is fish consumption. The rate of methylmercury accumulation depends on many factors including the amount, size, type and frequency of fish consumed, as well as contamination levels in the aquatic habitat. The ability to predict accurately human exposure to methylmercury through fish consumption is essential to the setting of public consumption guidelines. This paper describes the development of an innovative method of estimating human exposure to methylmercury through sport fish consumption by mathematical modelling. Through a judicious combination of fish methylmercury bioaccumulation models and survey information on human fish-eating habits, the model allows for a scientifically based estimation of the average daily exposure to methylmercury from fish consumption. It provides a practical tool to estimate the methylmercury uptake from a fish diet as governed by the diet frequency, fish species and fish size. The efficacy of the model is demonstrated by application to six common Lake Ontario fish species. Results showed that the human methylmercury exposure from fish consumption is a serious issue, as demonstrated by the exceedance of the tolerable daily intake levels in many instances. It was also found that the level of human methylmercury uptake depends heavily on the species of fish consumed; among the six species studied, walleye carries the highest risk, followed by yellow perch, while rainbow trout seems to be the safest with the lowest bioaccumulation levels.

Estimation of Intake Level of Di (2-ethyhexyl) phthalate (DEHP) of Japanese Pregnant Woman Based on Measurement of Concentrations of Three Urinary Metabolites

[corrected] The daily intake level of di (2-ethyhexyl) phthalate (DEHP) of Japanese pregnant women was estimated on the basis of the measurement of the urinary concentrations of three DEHP metabolites. Spot urine samples were collected from 42 pregnant women who visited the gynecology division of a hospital for routine health check between June and October, 2003. The urinary concentrations of three DEHP metabolites, namely, mono (2-ethyhexyl) phthalate (MEHP), mono (2-ethy-5-hydroxyhexyl) phthalate (MEHHP), and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) were measured by HPLC/MS/MS. The concentrations of urinary MEHP, MEOHP and MEHHP (n=40) were 3.27-39.5 (median 9.83), 1.51-41.0 (median 10.4) and 4.6-26.6 (median 10.9) microg/g cre, respectively. The ranges of the estimated daily intake of DEHP per body weight based on the MEHP, MEOHP and MEHHP concentrations (n=40) were 3.45-41.6 (median 10.4), 0.66-17.9 (median 4.55) and 1.47-8.57 (median 3.51) microg/kg/day, respectively. The maximum estimated intake level per body weight (41.6 microg/kg/day) reached the Tolerable Daily Intake (TDI) level of 40-140 microg/kg/day set by the Ministry of Health and Welfare (now the Ministry of Health, Labour and Welfare). The health risk of DEHP exposure of our study subjects was found to be minimum from the viewpoint of the current knowledge of its risk level, although the human health effects of low-level DEHP exposure have to be studied further.

Ion release from dental casting alloys as assessed by a continuous flow system: Nutritional and toxicological implications

Objectives The aims of this study were to quantify the metallic ions released by various dental alloys subjected to a continuous flow of saliva and to estimate the nutritional and toxicological implications of such a release. Methods Four pieces of three nickel-based, one noble, one high-noble and two copper–aluminum alloys were cast and then immersed in a continuous flow of artificial saliva for 15 days. To simulate three meals a day, casts were subjected to thrice-daily episodes, lasting 30 min each and consisting of pH decreases and salinity increases. After 15 days, the metallic ions in the artificial saliva were analyzed. Data were expressed as averaged release rate: μg/cm 2/day of ion released for each alloy. The highest value of 95% Cl of each ion was adapted to a hypothetical worst scenario of a subject with 100 cm 2 of exposed metal surface. The results were compared with the tolerable upper daily intake level of each ion. Results The copper–aluminum alloys released copper, aluminum, nickel, manganese and iron. The nickel-based alloys essentially released nickel and chromium, while the beryllium-containing alloy released beryllium and significantly more nickel. The noble and high-noble alloys were very resistant to corrosion. The amount of ions released remained far below the upper tolerable intake level, with the exception of nickel, released by beryllium-containing nickel-based alloy, whose levels approach 50% of this threshold. Significance The daily amount of ions released seems to be far below the tolerable upper intake levels for each ion.

Human Monitoring of Phthalates and Risk Assessment

Some phthalates, such as di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP), and their metabolites are suspected of producing teratogenic and endocrino-disrupting effects. In this study, urinary levels of phthalates (DEHP, DBP, diethyl phthalate (DEP), butylbenzyl phthalate BBP), and monoethylhexyl phthalate (MEHP, a major metabolite of DEHP) were measured by high performance liquid chromatography (HPLC) in human populations (women [hospital visitors], n = 150, and children, n = 150). Daily exposure level of DEHP in children was estimated to be 12.4 µg/kg body weight/d (male 9.9 µg/kg body weight/d, female 17.8 µg/kg body weight/d), but, in women was estimated to be 41.7 µg/kg body weight/d, which exceeded the tolerable daily intake (TDI, 37 µg/kg body weight/day) level established by the European Union (EU) Scientific Committee for Toxicity, Ecotoxicity, and the Environment (SCTEE) based on reproductive toxicity. Based on these data, hazard indices (HIs) were calculated to be 1.12 (41.7/37 TDI) for women and 0.33 (12.4/37 TDI) for children, respectively. These data suggest that Koreans (women and children) were exposed to significant levels of phthalates, which should be reduced to as low a level as technologically feasible to protect Koreans from the exposure to toxic phthalates.

History of Inuit Community Exposure to Lead, Cadmium, and Mercury in Sewage Lake Sediments

Exposure to lead, cadmium, and mercury is known to be high in many arctic Inuit communities. These metals are emitted from industrial and urban sources, are distributed by long-range atmospheric transport to remote regions, and are found in Inuit country foods. Current community exposure to these metals can be measured in food, but feces and urine are also excellent indicators of total exposure from ingestion and inhalation because a high percentage of each metal is excreted. Bulk domestic sewage or its residue in a waste treatment system is a good substitute measure. Domestic waste treatment systems that accumulate metals in sediment provide an accurate historical record of changes in ingestion or inhalation. We collected sediment cores from an arctic lake used for facultative domestic sewage treatment to identify the history of community exposure to Pb, Cd, and Hg. Cores were dated and fluxes were measured for each metal. A nearby lake was sampled to measure combined background and atmospheric inputs, which were subtracted from sewage lake data. Pb, Cd, and Hg inputs from sewage grew rapidly after the onset of waste disposal in the late 1960s and exceeded the rate of population growth in the contributing community from 1970 to 1990. The daily per-person Pb input in 1990 (720,000 ng/person per day) exceeded the tolerable daily intake level. The Cd input (48,000 ng/person per day) and Hg input (19,000 ng/person per day) were below the respective TDI levels at the time.

Seasonal dynamics of the hepatotoxic microcystins in various organs of four freshwater bivalves from the large eutrophic lake Taihu of subtropical China and the risk to human consumption

So far, little is known on the distribution of hepatotoxic microcystin (MC) in various organs of bivalves, and there is no study on MC accumulation in bivalves from Chinese waters. Distribution pattern and seasonal dynamics of MC-LR, -YR and -RR in various organs (hepatopancreas, intestine, visceral mass, gill, foot, and rest) of four edible freshwater mussels (Anodonta woodiana, Hyriopsis cumingii, Cristaria plicata, and Lamprotula leai) were studied monthly during Oct. 2003-Sep. 2004 in Lake Taihu with toxic cyanobacterial blooms in the summer. Qualitative and quantitative determinations of MCs in the organs were done by LC-MS and HPLC. The major toxins were present in the hepatopancreas (45.5-55.4%), followed by visceral mass with substantial amount of gonad (27.6-35.5%), whereas gill and foot were the least (1.8-5.1%). The maximum MC contents in the hepatopancreas, intestine, visceral mass, gill, foot, and rest were 38.48, 20.65, 1.70, 0.64, 0.58, and 0.61 microg/g DW, respectively. There were rather good positive correlation in MC contents between intestines and hepatopancreas of the four bivalves (r=0.75-0.97, p<0.05). There appeared to be positive correlations between the maximum MC content in the hepatopancreas and the delta13C (r=0.919) or delta15N (r=0.878) of the foot, indicating that the different MC content in the hepatopancreas might be due to different food ingestion. A glutathione (GSH) conjugate of MC-LR was also detected in the foot sample of C. plicata. Among the foot samples analyzed, 54% were above the provisional WHO tolerable daily intake (TDI) level, and the mean daily intakes from the four bivalves were 8-23.5 times the TDI value when the bivalves are eaten as a whole, suggesting the high risk of consuming bivalves in Lake Taihu.

Rapid methods for deoxynivalenol and other trichothecenes

Method development for deoxynivalenol (DON) and other trichothecenes in recent years was driven by the analytical necessities arising from its widespread (and increasing) occurrence in foods and feeds. This has resulted in the establishment of guideline levels for animal feed, tolerable daily intake (TDI) levels for humans, and most importantly, in the prospect of low-tolerance levels for these toxins in foods in the near future. In order to ensure reliable determination of the toxin content at the tolerance levels, routine analytical methods must have detection limits of less than the tolerance level. This paper intends to give an overview of current analytical developments of rapid testing for deoxynivalenol and other trichothecene mycotoxins, with a special focus on antibody-based techniques. This includes high-throughput instrumental analysis for the laboratory environment, as well as rapid visual tests for on-site testing. The applicability of rapid tests within an integrated detection system for mycotoxins in foods is discussed.

Low dose effects of bisphenol A on sexual differentiation of the brain and behavior in rats

There is an endocrinological concern that environmental endocrine disrupters (EEDs) may influence sexual differentiation. Bisphenol A (BPA), one of EEDs, is released from polycarbonate plastics, and has been detected in the human umbilical cord. In this study, we examined the effect of BPA on the sexual differentiation of open-field behavior and the sexually dimorphic nuclei in the brain in the offspring of rats exposed to BPA during the fetal and suckling periods at a dosage below the human tolerable daily intake (TDI) level. In the control group, females were more active in the open field and had a larger locus coeruleus (LC) volume than males. BPA abolished and inverted the sex differences of the open-field behavior and the LC volume, respectively, without affecting the reproductive system. We also compared the effects of estrogenic compounds, diethylstilbestrol (DES) and resveratrol (RVT), to that of BPA because of their structural similarities. DES affected the open-field behavior, LC volume and reproductive system, while RVT affected the LC volume and the reproductive system. These results suggest that the brain is highly sensitive to BPA at a dosage below TDI and that the disrupting effects of BPA on sexual differentiation may vary from those of RVT and DES.