Temporal trends in dioxin, furan and polychlorinated biphenyl concentrations in bovine milk from farms adjacent to industrial and chemical installations over a 15 year period

The concentrations of polychlorinated dibenzo-p-dioxins, furans and polychlorinated biphenyls (PCBs) were measured in pooled bovine milk samples collected between 1991 and 2005 in County Cork, Ireland. The pooled samples were of bulk-tank milk collected from farms adjacent to industrial, chemical and pharmaceutical installations (target milk) or from rural farms distant from industrial activity (control milk). Comparing data between the first and last 3-year periods of the study revealed a 62% decrease in the mean total dioxin concentration in target milk from 1.58 to 0.60pg toxic equivalents (TEQ)/g fat. On the same basis the dioxin-like PCB concentration in target milk decreased by 80% over the study period (from 0.95pg to 0.19pg TEQ/g fat). The mean 'marker' PCB concentration in target milk from 1991 to 1993 inclusive was 3359pg/g fat. This value decreased by 75% to a mean of 849pg/g fat for the years 2003-2005 inclusive. The results of this study are consistent with low background dietary/environmental PCB contamination in both target and control herds. The total dioxin concentrations in all samples were well below the maximum tolerable limits permitted for marketable milk. The decrease in the total dioxin concentration in target and control milk samples over the study period was chiefly due to decreases in the concentration of dioxin-like PCBs, consistent with significant reductions in the concentration of PCBs in the dairy cow diet over the 15 year study period.     

利用对β-谷甾醇含量的检测鉴别生鲜乳中掺假植物脂肪的研究

本试验建立了气相色谱―质谱法测定生鲜乳中β-谷甾醇的检测方法,由于理论研究表明生鲜乳中的乳脂肪是动物油脂,不应含有或很少含有植物油脂中特有的甾醇β-谷甾醇,因此对多个地区生鲜乳中β-谷甾醇的本底含量进行分析,给出生鲜乳中掺假植物油脂的鉴定方法。用质量比1.25的氢氧化钾水溶液25 mL皂化样品,100 mL维生素C的乙醇溶液作为稳定剂和抗氧化剂,皂化液用石油醚和乙醚萃取,转溶剂至甲苯,离心进样质谱。选用高柱效的60 m DB-5毛细管柱,进样量1 μL,程序升温在35 min内实现β-谷甾醇与其他醇类及杂质的良好分离。选择离子414定量,检出限为0.10 mg/L,线性相关系数r=0.9991。运用该方法对6个地区生鲜乳中β-谷甾醇含量进行检测,结果得到最高值为0.86 mg/L,常见植物油中β-谷甾醇的含量为1～3 g/L。表明生鲜乳中利用植物脂肪代替乳脂肪时,每提高1%植物脂肪将多产生最少相当于本底量12倍的β-谷甾醇,从而判定生鲜乳中是否掺假植物脂肪。     

Influence of polychlorinated biphenyls on LH-stimulated secretion of progestereone and oxytocin from bovine luteal cells

Polychlorinated biphenyls (PCBs) due to their lipophilic properties can be easily accumulated in animal and human body and elicit diverse effects causing impairment of reproductive processes. Since these compounds were not be able to affect directly the luteal steroidogenesis, the aim of the present study was to verify hypothesis that PCBs can impair the effect of LH on the secretory function of luteal cells. Bovine luteal cells from different stages of the oestrous cycle (days 1-5, 6-10, 11-15 and 16-18) were exposed for 72h to various congeners of PCBs (PCB 126, PCB 77 and PCB 153) at the doses of 1, 10 or 100 ng/ml, in the presence or absence of LH (100 ng/ml), to determine the possible effect of these compounds on progesterone (P4) and ovarian oxytocin (OT) secretion. Only PCB 77 on days 1-5 and 16-18 increased P4 secretion. All PCBs decreased LH-simulated secretion of P4 from luteal cells obtained from all days of luteal phase. Dioxin-like congener (PCB 126) inhibited (P<0.05) the most evidently LH effect on P4 secretion. All congeners, except the lower doses of PCB 126, increased (P<0.05) OT secretion. They can also increase LH-stimulated secretion of OT, but the effect was dependent on the congener used and on the phase of oestrous cycle. On days 1-5 and 10-15, PCB 126 diminished LH-stimulated effect on OT secretion from luteal cells. PCB 77 (mimickig both dioxin and estradiol effect) in the higher doses, amplified effect of LH-stimulated OT secretion, while on all other days it diminished LH influence. PCB 153, which has estrogen-like properties, amplified LH effect on OT secretion during all studied days of the cycle. We conclude that PCBs (supposedly via estrogen and arylhydrocarbon - AhR receptor) may directly affect LH-stimulated function of CL. This does not appear to be a direct adverse effect on luteal steroidogenesis, but rather indirect on OT secretion from or within CL.     

毛细管气相色谱法测定动物性食品中六六六和滴滴涕的残留量

采用毛细管气相色谱法对动物性食品中有机氯农药六六六（HCH）和滴滴涕（DDT）的残留进行检测。样品经高氯酸：冰醋酸（1：1,V/V）消化,正己烷提取,无水硫酸钠脱水,浓硫酸净化,采用DB5弹性石英毛细管柱,经程序升温分离,微电子捕获器（μECD）检测六六六和滴滴涕的残留量。方法的检出限为0．38～1．20μg/kg,加样平均回收率为81．37％～108．02％,相对标准偏差（RSD）为0．36％-2．35％。此方法灵敏度高,选择性好,操作简便。     

The effect of polychlorinated biphenyls (Delor 103, 105, and 106) in animal feed on the health of young pigs

Five trials involving 71 piglets and young porkers were conducted to test the toxic action of polychlorinated biphenyls (PCB) added to the complete feed mixtures as Delor 103, 105 or 106 (manufactured by Chemko Strázske) administered to the experimental groups. The intake of these biphenyls for 14 or 21 days at rates from 100 to 250 mg per kg of feed had no adverse effect on the health condition, production parameters and concentration of total protein, albumin, globulin, urea, glucose and cholesterol in blood serum. Delor 105 had the highest biological effectiveness: its intake increased the relative weight of liver, reduced the serum level of thyroid hormones and corticosteroids. When the weaned piglets consumed a starter feed with an addition of 1 mg of Delor 105 per kg (corresponding to a high natural PCB contamination) for 26 days, no adverse effect was recorded and, on the contrary, the growth of the animals was stimulated and their feed utilization was better. The results suggest that the young pigs are comparatively resistant to the toxic action of PCB.     

The effect of polychlorinated biphenyls (PCB) on chickens: the effect of long-term administration of medium doses of Delor 103 on the levels of thyroxine, triiodothyronine and total calcium in the blood serum

A trial with the continual administration of feed contaminated with the Delor 103 preparation (polychlorinated biphenyls--PCB) at a rate of 75 mg per kg for chicks lasted four weeks. The concentrations of serum thyroxine and triiodothyronine were found to decrease, the concentrations of total calcium increased and at the Delor 103 doses of 150 mg per kg even the phosphorus concentration and the activity of alkaline phosphatase in the serum of chicks decreased. The addition of potassium iodide to feed (250 mg per kg) did not influence the clinical picture of Delor 103 intoxication. The results confirm a finding that in the course of PCB intoxication severe disorders of the thyroid gland take place and calcium metabolism is disturbed. This finding is important in view of evaluation of the intoxication of young, growing chicks.     

Management of land and livestock contaminated with polychlorinated biphenyls

Investigations were conducted on several small neighbouring beef cattle and sheep farms that were found to be contaminated with polychlorinated biphenyls (PCBs). The residues detected contained about 62% w/w chlorine and soil concentrations ranged from 0.35 to 1.9 mg/kg. Beef cattle and sheep grazing the contaminated land had PCB concentrations in their fat of 0.3 to 1.7 mg/kg and 0.19 to 0.45 mg/kg, respectively. The concentration of PCBs in the caudal fat of cattle was 0.3 to 2 times the concentration of PCBs in the land they were grazing and was positively related to stocking rates. PCBs were present in milk fat from cattle at about the same concentration as in caudal fat, and lactation appeared to contribute to decontamination. Wool grease from sheep contained about 1 to 2 times the concentration of PCBs in subcutaneous fat. Calves of contaminated cows also became contaminated. The half-life for decontamination of PCBs in a group of 8 young female beef cattle was calculated at 13 months. PCBs were detected in pasture samples at concentrations ranging from less than 0.01 mg/kg to 0.12 mg/kg. However, PCBs were not detected in any sample of hay cut from these paddocks. In 4 sheep fed a sole ration of this hay, traces of PCBs were detected in their fat following 89 days of feeding. Grazing livestock for meat production on land contaminated with PCBs is not recommended because livestock readily acquire residues, and PCBs persist in soil and livestock for long periods. Grazing sheep for wool production on land contaminated with PCBs may be an option.     

PCB concentrations in hair, blood, tissues and secretions of chronically-exposed dairy cows, fattening bulls and calves. 1. Course and relation of some polychlorinated biphenyls in hair, milk and tissues in exposed nursing cows and conventionally raised dairy cows]

20 cows contaminated chronically with PCB were kept as nurse cows or in a tie-stall. The contamination in different substrates (hair, milk, blood, feces) was examined for a period up to 8 months. The distribution of PCB in the carcass of some animals was registered in addition. The system of keeping nurse cows turned out to be useful in order to overcome a contamination situation. Drying off gravid animals in the first step helps solving problems of handling contaminated milk. With low contaminated animals a short dry off period is sufficient, so that the milk--after calving--is marketable (report II, in preparation). In case of nurse cows with two calves post partum a continuous decline of PCB-concentrations in the milk can be observed. With biological half life periods of 2-4 months, milk with PCB 153-concentrations of 0.15-0.20 mg/kg fat will be marketable within this period. Cows milked by milking-machines show a decline of PCB in the milk similar to nurse cows. Two animals had a limited increase p.p., probably caused by mobilization of fat in the high lactation stage. Over longer periods, the biological half-life-periods were comparable to nursing cows. Hair is easy to sample and store; it is useful as a diagnostic substrate beside the milk in order to estimate the degree of contamination in individual animals. The ratio of PCB-concentrations between perirenal fat and hair is 1:0.95 (s = +/-0.192); the ratio of PCB-concentrations between perirenal fat and milk is 1:0.77 (s = +/- 0.122).(ABSTRACT TRUNCATED AT 250 WORDS)     

A gas-chromatographic headspace method for the determination of acetone in bovine milk, blood and urine

An automated headspace gas-chromatographic method has been developed for the determination of acetone in the milk, blood and urine of dairy cows. Five ml samples were saturated with 2 g of sodium chloride and equilibrated for 30 min at 90 degrees C in a Hewlett-Packard HP 19395 A automatic headspace sampler. The headspace volatiles were transferred without splitting to a 25 m x 0.3 mm x 0.4 microns Carbowax column in a Shimadzu GC 9A gas chromatograph, operating isothermally at 50 degrees C. The coefficients of variation for the determination of acetone were 1.5-4.4% for urine, 10.0-24.9% for milk and 2.0-19.6% for blood. The detection limits were 0.0055 mg/100 ml for milk, 0.0072 mg/100 ml for blood and 0.0080 mg/100 ml for urine. The analysis time of 5 min per sample provided an adequate rate of throughput for routine monitoring.     

Animal-derived feeds as possible vectors for bovine spongiform encephalopathy (BSE) in Germany. 1. Comparative risk assessment for a single animal food of animal origin

The occurrence of BSE cases in Germany after the ban of meat and bone meal for ruminant feed in 1994 requires a detailed investigation of animal derived feedstuffs regarding their specific risks as vectors for the disease. Accepting the theory that BSE is a prion transmitted disease, the theoretical infectious potential was calculated for animal derived feedstuffs. This calculation was based on the assumption, that risk material (brain, spinal cord) of one clinically diseased cattle was rendered in the process as established in Germany (133 degrees C, 3 bar, 20 min) or, alternatively, that one diseased animal was slaughtered resulting in normal processing of the by-products for human food production. From this risk assessment it became obvious that meat and bone meal was one, but probably not the most important source for the spreading of BSE. Taking into account the high sensitivity of calves it can be speculated that certain products, e.g. from bone processing (bone meal) and fat melting (mixed animal fats), commonly used for the formulation of milk replacers, might have been more important as pathways. As it can't be excluded retrospectively that infected meat and bone meal was imported from the UK, this non-calculable influence may have been related to the significance of the other products. The calculation model underlines that efficient removal of specified risk material (brain, spinal cord) and adequate processing (133 degrees C, 3 bar, 20 min) or alternatively other equivalent treatments of fats are prerequisites for minimising the risk of feed borne transmission of BSE by animal derived feedstuffs. The epidemiological consequences are part of a subsequent paper.     

Flotation of mastitis pathogens with cream from subclinically infected quarters. Prospects for developing a cream-rising test for detecting mastitis caused by major mastitis pathogens

Bacterial isolates, originating from 36 subclinically infected quarter milk samples, were labelled with 75Se and checked for cream-rising at various temperatures in a system analogous to the ABR test ("Abortus Bang Ringprobe"; the cream-rising test based on stained brucella organisms for detection of brucellosis). Diagnostic specificity and sensitivity were analyzed in experiments where labelled bacterial isolates were mixed with a number of quarter milk samples with known bacteriological status as well as samples from healthy control quarters. Creaming at 37 degrees C resulted in specific "recognization" as the bacterial isolates showed preferential flotation in the milk samples from which they had been isolated as well as is milk samples harbouring the same bacterial species. At lower creaming temperatures, the specificity was lost since all the isolates became concentrated in the cream phase irrespective of the milk sample. When comparing the specific recognization by cream of the respective bacteria, bacterial species vary: The prospects for developing diagnostic cream-rising tests for Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli seems promising, but less so for coagulase-negative staphylococci, Streptococcus dysgalactiae, and Streptococcus uberis. The mechanism behind the cream-rising of labelled bacteria at 37 degrees C seems to lie in specific fat globule membrane-bound immunity of IgA type. Therefore the milk fat globules from chronically infected quarters function as absorbents for the respective isolates. Flotation of bacteria with cream indicates an in vivo mechanism enabling bacteria to invade the upper parts of milk ducts within the udder.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dynamics of exogenous progesterone in the blood of pigs stressed with polychlorobiphenyls (PCB)

For a period of 70 days, young gilts were given rations containing a commercial mixture of polychlorinated biphenyls (PCB), produced in Czechoslovakia (Delor 105). One group of animals (A) was given feed containing 10 mg chlorobiphenyls per kg, the other group (B) was given feed containing 50 mg chlorobiphenyls per kg; on the whole, each animal of group A got 1 g of PCB mixture and each animal of group B 5 g. In about the mid-time of the experiment and before its termination the animals were given an i. m. injection of progesterone; then the animals were studied for the changes in the concentration of blood plasma progesterone. Statistically significant (P less than 0.05) and highly significant (P less than 0.01) differences in the values of the biological half-life of progesterone were found between the group of PCB-treated animals and the control group, and between groups A and B.     

The effect of polychlorinated biphenyls on the vitamin A, vitamin E, and ascorbic acid status in young pigs

Admixture for 14 to 26 days of concentrations between 1 mg/kg to 250 mg/kg of polychlorinated biphenyls, Delor 103, 105, and 106 (Chemko, Strázeke) to ready-mixed feedstuffs was studied in 5 experiments for its effects on 71 piglets and store pigs. Neither growth nor general health were in any way impaired. Polychlorinated biphenyls produced different effects upon vitamin A, vitamin E, and ascorbic acid levels in different organs. Vitamin A concentrations in blood serum, for example were reduced by 100 mg/kg and 250 mg/kg of Delor 105 as well as by 250 mg/kg of Delor 103. Liver levels were not significantly depressed. No changes were recordable from vitamin E levels in blood serum and liver. Ascorbic acid saturation of the organism was positively affected. Its concentrations and overall levels in the liver in all experimental groups were higher than those in all controls. Significant rise of ascorbic acid concentrations in blood serum, urine, and kidneys occurred merely in response to 100 mg/kg and 250 mg/kg of Delor 105 as well as to 250 mg/kg of Delor 103. No adverse effect of tissue-borne residues of polychlorinated biphenyls on the status of administered vitamins was recordable 1 to 4 months after termination of experimental supply. Feed intake with 1 mg/kg of Delor 105, which was equivalent to increased natural contamination, did not cause any negative phenomena in any of the probands.     

The effect of polyclorinated biphenyls in chickens: the effect of short-term administration of high doses of Delor 103 on the levels of thyroxine, triiodothyronine, sodium, potassium and calcium in the blood

The trial with a short-time receiving (7 days) of high doses of the preparation Delor 103 (PCB) to chickens (1000 mg.kg-1 feed stuffs) had a long-run negative effect on their state of health. Clinical picture of intoxication resembled an involution syndrome. A defect persistence of the conversion of thyroid hormone T4 to T3 was found. Regeneration of T4 hormone production was rather fast. Supplement of hormones T4 and T3 to feed had no significant influence on the course of intoxication, but it caused changes in concentrations of K+, Ca++, and the total calcium in the blood serum of the birds. Simultaneous supplement of Delor 103 moderated the intensity of changes induced by exogenous flow of thyroid hormones. Histological changes were demonstrated in the primary lymph organs, which supported of findings of immunosuppressive effect in PCB. Supplement of the thyreostatic Carbimazol (Carbimazolum/1-carbaetoxy-3-methyl-2-thioimidazolin um) caused no symptoms testifying to hypofunction of thyroid gland in chickens.     

Tissue deposition of polychlorinated biphenyls in cats fed Atlantic Ocean bluefish.

Bluefish (Pomatomus saltatrix), a very popular marine sport fish caught in Atlantic coastal waters, contain significant levels of polychlorinated biphenyls (PCBs). Since fish can be an appreciable portion of human and feline diets, a feeding study was conducted with cats fed exclusively bluefish for 86 days with determination of tissue concentrations of PCBs. The concentrations of PCBs in brain, liver, and fat were significantly higher (p = 0.01) in the fish-fed cats than in the control group using the Wilcoxon rank sum test. The highest PCB levels were in fat, the median concentrations being 48 and 0.61 ppm (dry weight) in the fish-fed and control cats, respectively. The significance of the results is discussed.     

Persistent organic pollutants in meat,liver, tallow and bone marrow from semi-domesticated reindeer (Rangifer tarandus tarandus L.) in Northern Norway

Background

The aim of this project was to study 14 polychlorinated biphenyls (PCBs), 5 dichlorodiphenyl trichloroethans (DDTs), 12 organochlorine pesticides (OCPs) and 6 polybrominated diphenylethers (PBDEs) in meat, liver, tallow and bone marrow from semi-domesticated reindeer.

Methods

Meat, liver, tallow, and bone marrow samples (n= 30) were collected from semi-domesticated reindeer in Northern Norway. Determination of the persistent organic pollutants (POPs) concentrations was done by using gas chromatography–mass spectrometry (GC-MS). Dependent sample t-test and Pearson’s correlation test were used in statistical analysis.

Results

Concentrations of the persistent organic pollutants in the samples from semi-domesticated reindeer were generally low and slightly above the limit of detection (LOD). For PCBs and OCPs, ≥ 50% of the samples had concentrations above LOD. For the DDTs and PBDEs, the proportion of samples with concentrations above LOD varied between 3.7 and 45.5% depending on the sample type. Concentrations of PCB 99, 105, 138/163, 153 and 187 differed significantly between meat and liver, whereas concentrations of PCB 183 were significantly different between tallow and bone marrow. Furthermore, concentrations of hexachlorobenzene (HCB) were significantly different between meat and liver. Significant correlations were revealed in concentrations of 5 PCB congeners between the studied tissue types.

Conclusion

Concentrations of the POPs revealed in this study were generally low.     

乳粉中1-油酸-2-棕榈酸-3-亚油酸甘油三酯的测定

建立乳粉中1-油酸-2-棕榈酸-3-亚油酸甘油三酯（1-oleic-2-palmitic-3-linoleic acid triglyceride，OPL）的气相色谱检测方法。样品经乙醚和石油醚提取，提取液浓缩近干，正庚烷定容，通过CP-TAP CB弹性石英毛细管柱分离，以氢火焰离子化检测器检测，外标法定量。结果表明：通过CP-TAP CB弹性石英毛细管柱程序升温分离，进样口温度330 ℃，分流进样，分流比1∶10，进样体积1.0 μL；氢火焰离子化检测器温度360 ℃，载气：氮气，尾吹流量（氮气）25 mL/min；乳粉中OPL的添加量为1～6 g/100 g时，加标回收率为95.2%～101.9%，相对标准偏差为1.289%～1.998%；方法的检出限为0.2 g/100 g，定量限为1.0 g/100 g。该方法操作简单、结果准确、重复性好，适用于乳粉中OPL的测定。     

Reduction of aflatoxin M1 in milk using hydrogen peroxide and hydrogen peroxide plus heat treatment.

Use of hydrogen peroxide (H2O2) under various conditions of temperature and time to inactivate aflatoxin M1 in artificially contaminated raw milk was examined. The degree of inactivation was measured by Enzym Linked Immunosorbent Assay (ELISA). It appeared that there is no change in the content of aflatoxin M1 in milk contained H2O2 and examined after 24 hours without heat treatment and in contaminated milk without add of H2O2 and heat treated treatment at (63 degrees C for 30 min, 75 degrees C for 15 sec) but slight inactivation (4.3%) was obtained in milk boiled for 5 min without H2O2. Maximum inactivation (27.8%, 28.8% and 45.1%) were obtained using 1% H2O2 followed by heat treatment at 36 degrees C for 30 min, 75 degrees C for 15 sec and boiling for 5 min respectively.     

Suppression of heat-stable enterotoxin production by Yersinia spp. in milk

One of 16 raw milk isolates of Yersinia enterocolitica and Y. intermedia produced heat-stable enterotoxin (ST) in milk at 25 degrees C but not at 4 degrees C after 21 days of incubation. A catabolite repression of ST synthesis by the lactose-fermenting strain of Y. enterocolitica was observed when 4.6% lactose was added to trypticase soy broth. However, the lactose-fermenting strain was killed by acid produced by lactose fermentation in milk and did not produce ST in milk with the pH adjusted to neutrality. This study suggested that lactose and fat in milk are not the fundamental inhibitors of ST synthesis by Y. enterocolitica and that repression of ST synthesis may be related to other components.     

The effects of dietary fat or fiber addition on yield and composition of milk from sows housed in a warm or hot environment

Sixty sows were individually penned in a thermoneutral (20 degrees C) or hyperthermal (32 degrees C) environment and fed a basal (corn-soybean meal), high-fiber (48.5% wheat bran) or high-fat (10.6% choice white grease) diet from d 100 of gestation through a 22-d lactation. The diets were determined to contain 3.28, 2.76 and 3.75 Mcal ME/kg, respectively. All pigs received 8.0 Mcal of ME and 17.5 g of lysine daily prior to parturition and were allowed to consume their respective diets ad libitum after parturition. Litter size was standardized at 9 to 10 pigs by d 2 postpartum. Milk yields were determined for five, 4-d periods from about d 2 through 22 of lactation via a D2O dilution technique. Daily milk yield and litter weight gain began to plateau, and the efficiency of utilizing milk DM and milk energy for gain was depressed (P less than .01), in the latter stages of the lactation. Heat exposure (32 degrees C) reduced (P less than .05) voluntary ME intake and milk energy yield of the sow and increased (P less than .05) the sow's weight loss during lactation. In the hot environment, increasing dietary energy concentration resulted in a linear (P less than .08) increase in milk fat content and milk energy yield over the duration of the 22-d lactation. In the latter stages of lactation, pigs consuming high-fat milk required more (P less than .09) milk and milk energy per unit of weight gain. In the warm environment, milk energy yield was increased by dietary fat or fiber additions in early lactation, but not in late lactation. These results indicate that the effects of thermal heat stress on sow milk energy yield and litter weight gain are aggravated by dietary fiber addition and minimized by dietary fat addition.