Toxicokinetics of PCDD, PCDF, and coplanar PCB congeners in Baikal seals, Pusa sibirica: age-related accumulation, maternal transfer, and hepatic sequestration

To assess the toxicokinetic behavior and potential toxicity of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) in Baikal seals, congener-specific levels and tissue distribution were evaluated in the liver and blubber, and the effects of biological factors including sex and growth were assessed. Total 2,3,7,8-TCDD toxic equivalents (TEQs) were in the range of 210-920 pgTEQ/g fat wt (180-800 pgTEQ/g wet wt) in the blubber and 290-7800 pgTEQ/g fat wt (10-570 pgTEQ/wet wt) in the liver. Non-ortho coplanar PCB126 was the most TEQ-contributed congener accounting for 37-59% of the total TEQs in the liver. From the unique congener profiles, weak metabolic properties of Baikal seals for 2,3,7,8-TCDF and 1,2,3,7,8-P5CDF are suggested. Concentrations of most congeners linearly increased with age in male seals, whereas in adult females the levels revealed an age-related decline. The increasing and declining rates were congener-specific. Maternal transfer rates of 5 representative congeners from adult female to pup through lactation, which was estimated from male-female differences in the body burden, was 1.1 ngTEQ/kg/day for the first pup and decreased with every lactational epoch. The liver-blubber distribution of 1,2,3,4,7,8-H6CDD, 1,2,3,6,7,8-H6CDD, PCB81, PCB126, and PCB169 was dependent on the hepatic total TEQ, indicating hepatic sequestration by induced cytochrome P450 (CYP). These results indicate that congener profile in Baikal seals is governed by complex factors including sex, tissue concentration, binding to CYP, and rates of absorption and metabolism/excretion.     

Bioaccumulation, temporal trend, and geographical distribution of synthetic musks in the marine environment

Bioaccumulation of synthetic musks in a marine food chain was investigated by analyzing marine organisms at various trophic levels, including lugworm, clam, crustacean, fish, marine mammal, and bird samples collected from tidal flat and shallow water areas of the Ariake Sea, Japan. Two of the polycyclic musks, HHCB and AHTN, were the dominant compounds found in most of the samples analyzed, whereas nitro musks were not detected in any of the organisms, suggesting greater usage of polycyclic musks relative to the nitro musks in Japan. The highest concentrations of HHCB were detected in clams (258-2730 ng/g lipid wt.), whereas HHCB concentrations in mallard and black-headed gull were low, and comparable with concentrations in fish and crab. These results are in contrast to the bioaccumulation pattern of polychlorinated biphenyls; for which a positive correlation between the concentration and the trophic status of organisms was found. Such a difference in the bioaccumulation is probably due to the metabolism and elimination of HHCB in higher trophic organisms. Temporal trends in concentrations of synthetic musks were examined by analyzing tissues of marine mammals from Japanese coastal waters collected during 1977-2005. HHCB concentrations in marine mammals have shown significant increase since the early 1990s, suggesting a continuous input of this compound into the marine environment. Comparison of the time trend for HHCB with those for PCBs and PBDEs suggested that the rates of increase in HHCB concentrations were higher than the other classes of pollutants. To examine the geographical distribution of HHCB, we have analyzed tissues of fish, marine mammals, and birds collected from several locations. Synthetic musks were not detected in a sperm whale (pelagic species) from Japanese coastal water and in eggs of south polar skua from Antarctica. While the number of samples analyzed is limited, these results imply a lack of long-range transportation potential of synthetic musks in the environment.     

青岛市牡蛎养殖场副溶血性弧菌污染水平及时间分布

目的 了解青岛市牡蛎养殖场副溶血性弧菌污染水平及在不同的季节随时间和温度变化的趋势,为食品安全风险评估提供参考.方法 在2013年6月—2014年5月采用最大可能实时荧光定量聚合酶链式反应(themost probable number real-time polymerase chain reaction,MPN r...     

Vertical and temporal distribution of persistent organic pollutants in Toronto. 1. Organochlorine pesticides

From May to September 2005, five passive air samples were deployed over five, 1-month periods at five elevations on the CN Tower in Toronto, Canada, to investigate the vertical distribution, seasonality, and sources of organochlorine pesticides. A strong seasonality was observed between spring and the end of summer. Vertical profiles differed for different pesticide classes. For instance, alpha- and gamma-hexachlorocyclohexane exhibited higher concentrations (60-80 pg m(-3), respectively) near the ground during the spring and early summer, suggesting that surface-air exchange within the city or nearby Lake Ontario may be important sources. The vertical profile for chlordane isomers was variable, suggesting that both advective and local inputs are important. For dieldrin, no obvious trend with elevation was observed, suggesting that concentrations could reflect a regional air mass contamination. Strongest seasonality was observed for the endosulfans, a widely used pesticide in North America, that reached peak concentrations of 750-850 pg m(-3) during June/July. Advective inputs of endosulfan from regional or more distant agricultural regions can explain the relatively uniform concentrations with elevation throughout the study period. The approach used in this study demonstrates that monthly average vertical concentration profiles differ between pesticide groups and reflect their use as well as the relative magnitude of input from local versus regional sources.     

Spatial distribution and temporal variability of arsenic in irrigated rice fields in Bangladesh. 1. Irrigation water

Around 38% of the area of Bangladesh is irrigated with groundwater to grow dry season crops, most importantly boro rice. Due to high As concentrations in many groundwaters, over 1000 tons of As are thus transferred to arable soils each year, creating a potential risk for future food production. We studied the reactions and changing speciation of As, Fe, P, and other elements in initially anoxic water during and after irrigation and the resulting spatial distribution of As input to paddy soils near Sreenagar (Munshiganj), 30 km south of Dhaka, in January and April 2005 and February 2006. The irrigation water had a constant concentration of 397 +/- 7 microg L(-1) As (approximately 84% As(III)), 11 +/- 0.1 mg L(-1) Fe, and 2 +/- 0.1 mg L(-1) P. During the fast flow along the longest irrigation channel (152 m) As, Fe, and P speciation changed, but total concentrations did not decrease significantly, indicating that As input to fields was independent of the length of the irrigation channels. In contrast, during slow water flow across the fields, As, Fe, and P concentrations decreased strongly with increasing distance from the water inlet, due to formation and settling of As- and P-bearing Fe aggregates and by adsorption to soil minerals. Total As concentrations in field water were approximately 3 times higher close to the inlet than in the opposite field corner shortly after irrigation, and decreased to below 35 microg L(-1) over the next 72 h. The laterally heterogeneous transfer of As, Fe, and P from irrigation waterto soil has important consequences for their distribution in irrigated fields and needs to be considered in sampling and in assessing the dynamics and mass balances of As fluxes among irrigation water, soil, and floodwater.     

Regional trend and tissue distribution of brominated flame retardants and persistent organochlorines in raccoon dogs (Nyctereutes procyonoides) from Japan

The present study investigated concentrations and patterns of brominated flame retardants, such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs), and persistent organochlorines (OCs) in liver and adipose tissues of raccoon dogs (RD: Nyctereutes procyonoides) collected from two metropolises and a local prefecture in Japan during 2001-2006. Relatively high concentrations of PBDEs were found in RD livers, while HBCD levels were the lowest among the measured organohalogen compounds. Among PBDE congeners, BDE 209 was predominant in RDs from all the regions, indicating that pollution derived from the technical decaBDE product is extensive across Japan. On the other hand, concentrations of tetra- to nona-BDE congeners in RDs from a metropolis were significantly higher than those from the other two regions, implying that there were regional differences in the past usage of the technical tetraBDE and octaBDE products. Such a regional difference was also observed for HBCD levels. Lipid-normalized concentration ratios of liver to adipose tissue (L/A ratio) for tri to hepta-BDE congeners were lower than 1.0 in the investigated eight RDs, suggesting lipid-dependent accumulation. However, the LA ratios of BDE 209 exceeded 1.0 in all the specimens, suggesting hepatic retention of this compound. In addition, lipid-dependent accumulation of a-HBCD was observed, but the L/A ratios of gamma-HBCD were greater than 1.0 in some specimens. These results indicate that Japanese RDs have been recently exposed to BDE 209 and gamma-HBCD and accumulated both these compounds preferentially in blood-rich organs, probably due to their binding to proteins and/or rapid biotransformation, as reported in experimental rodents.     

长江中下游地区克氏原鳌虾氨基脲污染现状及组织分布特征

目的 了解长江中下游地区克氏原鳌虾中呋喃西林代谢物氨基脲暴露水平及组织分布特征.方法 根据中国小龙虾产业发展报告(2020),对长江中下游9个主要养殖产区进行克氏原螯虾样品的采集,参考农业部783号公告,对克氏原鳌虾样本水解后,在37℃恒温条件下避光衍生化16 h,后净化提取,通过液相色谱-串联质谱法对克氏原鳌虾整体及...     

Iodine absorption, excretion, recycling, and tissue distribution in the dairy cow.

Research on iodine metabolism was reviewed with special reference to cattle and milk secretion. Iodine metabolism in the fetus and thyroid activity as related to milk secretion and iodine feeding have also been considered. Between 70 and 90% of dietary iodine is absorbed directly from the bovine rumen, reticulum, and omasum. In the abomasum, rate of iodide secretion is approximately 18 times the rate of absorption. Circulating thyroxine is not secreted into the abomasum but enters the small intestine in the bile. Most of the iodide secreted into the abomasum is reabsorbed from the small and large intestines; absorption of thyroxine averages less than 10%. The thyroid usually contains an amount of iodine equal to the daily dietary intake; extrathyroidal tissues concentrate only .006 to .04% as much radioiodine per unit weight as the thyroid. At normal iodine intake (less than 10 mug/kg body weight daily), iodine losses average 30% of the daily intake in feces, 40% in urine, and 8% in milk. Milk iodine is influenced by amount and chemical form of dietary iodine, stage of lactation or milk yield, seasonal effects, goitrogens, and thyroid status. Cows secrete less iodine into milk than most other species and have an efficient iodine recycling system via the gastrointestinal tract which conserves iodine and can protect them against low dietary iodine.     

Enantiomeric specificity of methylsulfonyl-PCBs and distribution of bis(4-chlorophenyl) sulfone, PCB, and DDE methyl sulfones in grey seal tissues

PCB methyl sulfones (MeSO2-PCBs) are lipophilic PCB metabolites of which five of the environmentally relevant meta/para pairs are chiral (i.e., exist as atropisomeric pairs). Methylsulfonyl-DDE (MeSO2-DDE) is a DDE metabolite, while bis(4-chlorophenyl) sulfone (BCPS) is a commercial monomer used for thermoplastic production. All these sulfones are well-known environmental contaminants. In this study, liver, lung, and adipose tissue in grey seals (Halichoerus grypus) from the Baltic Sea, naturally exposed to organochlorines via their food, were analyzed for the compounds mentioned. MeSO2-PCBs, 3-MeSO2-DDE, and BCPS were all found in significantly higher concentrations in the liver than in lung and blubber. Their strong liver retention, represented by a median of 42 microg/g l.w. of sigmaMeSO2-PCBs, has previously been mainly neglected in assessments of exposure. The highest concentrations of PCBs and DDE were still found in the grey seal blubber. The atropisomeric composition of MeSO2-PCB congeners was determined, and their enantiomeric fractions were calculated and compared in blubber, liver, and lung tissues. The enantiomeric specificity was equal in all tissues. A notably high abundance (>94%) was observed for one atropisomer in each chiral MeSO2-PCB pair. The first eluting atropisomer (A1) was dominating for all para-substituted MeSO2-PCBs studied, while the second eluting atropisomers (A2) were as dominant in all meta-substituted MeSO2-PCBs in all samples analyzed. In the liver, as much as 50% of sigmaMeSO2-PCBs consisted of the second eluting atropisomer (A2) of 5-MeSO2-CB149. The results imply that the sulfone group is crucial for the specific liver retention of MeSO2-PCBs, 3-MeSO2-DDE, and BCPS.     

Carnitine in milk: a survey of content,distribution and temporal variation

Acid-soluble free carnitine and short-chain acylcarnitines were released following a selective alkaline hydrolysis scheme and estimated with use of a coupled carnitine acetyl transferase–Ellman reaction. Liquid skim milk contained elevated total carnitine levels compared to whole milk, due both to the minor contribution of liposoluble long-chain acylcarnitines in milkfat and the higher solids-not-fat content. Data are also reported for a range of dried protein products derived from milk (1–64 mg/100 g), and the stability characteristics of endogenous carnitine are described. A study of a single lactating cow exhibited decreasing concentrations of total carnitine with time postpartum during transition from colostrum to mature milk (>9 mg/100 g to ca. 3 mg/100 g). Regional influences on bovine milk carnitine levels within Australasia were shown to be insignificant, while carnitine content in milk powders and pooled herd milk were relatively constant across a production season. Bovine milk was compared against samples of caprine, ovine, equine, human, canine and feline milks. A survey of anhydrous infant formulas indicated diverse carnitine contents (6.9–30.1 mg/100 g) as a consequence of their complex and varied compositions and the common practice of supplementation.     

Blood and tissue distribution of gamma glutamyl transferase in calves.

In five male and five female calves, we studied the tissue distribution of gamma-glutamyl transferase. The enzyme was mainly in kidney, pancreas, and liver; there was no sex-related difference. The relative hepatic and pancreatic specificity of the enzyme indicated that the measure of its activity in serum could be a test of hepatic or pancreatic damage in the calf. Serum activity measured within 159 samples of apparently healthy calves was 15.3 +/- 3.7 U/liter, not differing significantly from that of adult cow.     

Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana).: 1. Yield and vigour inter-relationships

Vegetative growth and yield of grapevines grown in the field on their own roots or grafted to a range of rootstocks were investigated under drip irrigation with water of three salinity levels (0.40, 1.75 and 3.50 dS/m) over a five‐year period. Rootstocks were Ramsey, 1103 Paulsen, J17–69 and 4 hybrids (designated R1, R2, R3 and R4) derived from parentage involving Vitis champini, V. berlandieri and V. vinifera. Of measured yield components (bunches per shoot, bunches per vine, weight per bunch, weight per berry and total yield), only weight per berry was significantly reduced by high salinity (3.50 dS/m) in each year of the trial with the exception of Sultana on 1103 Paulsen and R2 in 1991 and Sultana on Ramsey in 1993. Weights of one‐year‐old pruning wood were also reduced by high salinity in all years for own roots and all rootstocks, with the exception of R2. Mean yield values at each salinity level over the five‐year period of the trial were highest for Sultana on Ramsey, 1103 Paulsen and R2. High salinity had no effect on five‐year mean yields of Sultana on Ramsey, 1103 Paulsen and R2. Yield (five‐year means) of Sultana on Ramsey and R2 at 1.75 dS/m were significantly higher than at 0.40 dS/m by 14.6% and 13.4% respectively. In contrast, 5‐year mean yields of Sultana on J17–69, own roots, R1, R3 and R4 at 3.50 dS/m were reduced by 54, 30, 20, 30 and 30% respectively. Yield of Sultana on J17–69, R1 and R4 rootstocks was reduced by 47, 20 and 24% respectively at 1.75 dS/m. When yield was regressed against bunches per vine and weight per bunch for Sultana on own roots and on Ramsey rootstock, bunches per vine was the main determinant of yield, while weight per berry showed a poor correlation with yield at all salinity levels. Rootstock ranking for salt tolerance based on yield at high salinity was the same as rankings for pruning wood weights at high salinity. The same occurred at medium salinity, demonstrating that vigour imparted by the rootstock was a major factor in Sultana salt tolerance as measured by yield. Mean root weighted soil saturation paste electrical conductivities (RWEC_e) (determined from soil saturation paste salinities and root length densities) were in the range 2.0–2.6 dS/m for the low salinity treatment, increasing to approximately 5.4 dS/m with increasing salinity of irrigation water. Yield reduction for own‐rooted vines for each 1.0 dS/m increase in RWEC_e above 2.6 dS/m was 9.3%.     

Aflatoxin (B1, B2, G1, and G2) Contamination in Rice of Mexico and Spain,from Local Sources or Imported

Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B₁, B₂, G₁, and G₂) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high‐pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 μg/kg, the range was from 1.6 to 1383 μg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 μg/kg), from Tortosa, Tarragona (AFt = 104.6 μg/kg), and Calasparra, Murcia (AFt = 103.9 μg/kg). The rice imported from France to Spain had AFt of 26.6 μg/kg and from Pakistan AFt of 18.4 μg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 μg/kg), and those imported from the United States (AFt = 14.4 μg/kg) and Uruguay (AFt = 15.6 μg/kg). The imported rice had better quality in terms of the presence of AFs.     

Blood and tissue distribution of gamma glutamyl transferase in the cow.

To test the hepatic specificity of gamma-glutamyl transferase in the cow, the tissue distribution of this enzyme was studied in 10 healthy adult cows. It was located mainly in kidney, pancreas, and liver. The relative hepatic specificity of this enzyme indicated that measurement of its activity in serum could be a valuable test of hepatic damage in the cow. The blood activity measured within 54 plasmas and 54 serums of apparently healthy animals was almost the same, 17.7 +/- 5.7 U/liter for plasma and 18.6 +/- 6.2 U/liter for serum.     

Dose-response feeding study of short chain chlorinated paraffins (SCCPs) in laying hens: effects on laying performance and tissue distribution, accumulation and elimination kinetics

Technical short chain chlorinated paraffins (C10-C13 with 60% chlorine) were fed to 93 laying hens from 24 to 32 weeks of age in increasing concentrations of up to 100 mg/kg feed. No significant influence on health, relative organ weights or performance (laying intensity, egg weight, feed consumption) was noted. The chlorinated paraffin content of the tissues was linearly related to the concentration of short chain paraffins of the feed. The highest concentrations were found in abdominal fat, egg yolk and fatty tissues. Breast muscle, egg albumen and bile fluid contained minimal or no residues. Less than 1% of the chlorinated paraffins ingested were incorporated into the body (without head, feet, gut and feathers), whereas about 1.5% were eliminated with the egg yolk and 30% were excreted with urine and faeces. A six-week kinetic depuration study revealed a biphasic elimination with half-lifes of 4-40 min (liver, kidneys, legs, fat, blood) for the initial rapid phase, and 15-30 days (blood, fat, liver, yolk, kidneys, legs) for the terminal slow phase.     

Spatial distribution and temporal variability of arsenic in irrigated rice fields in Bangladesh. 2. Paddy soil

Arsenic-rich groundwater from shallow tube wells is widely used for the irrigation of boro rice in Bangladesh and West Bengal. In the long term this may lead to the accumulation of As in paddy soils and potentially have adverse effects on rice yield and quality. In the companion article in this issue, we have shown that As input into paddy fields with irrigation water is laterally heterogeneous. To assess the potential for As accumulation in soil, we investigated the lateral and vertical distribution of As in rice field soils near Sreenagar (Munshiganj, Bangladesh) and its changes over a 1 year cycle of irrigation and monsoon flooding. At the study site, 18 paddy fields are irrigated with water from a shallow tube well containing 397 +/- 7 microg L(-1) As. The analysis of soil samples collected before irrigation in December 2004 showed that soil As concentrations in paddy fields did not depend on the length of the irrigation channel between well and field inlet. Within individual fields, however, soil As contents decreased with increasing distance to the water inlet, leading to highly variable topsoil As contents (11-35 mg kg(-1), 0-10 cm). Soil As contents after irrigation (May 2005) showed that most As input occurred close to the water inlet and that most As was retained in the top few centimeters of soil. After monsoon flooding (December 2005), topsoil As contents were again close to levels measured before irrigation. Thus, As input during irrigation was at least partly counteracted by As mobilization during monsoon flooding. However, the persisting lateral As distribution suggests net arsenic accumulation over the past 15 years. More pronounced As accumulation may occur in regions with several rice crops per year, less intense monsoon flooding, or different irrigation schemes. The high lateral and vertical heterogeneity of soil As contents must be taken into account in future studies related to As accumulation in paddy soils and potential As transfer into rice.