Single-longitudinal-mode optical parametric oscillator for spectroscopic applications

We have developed a tunable, narrow-bandwidth nanosecond optical parametric oscillator system and applied it to spectroscopic studies. The system consists of a narrow-bandwidth grazing-incidence oscillator and a seeded power oscillator, generating Fourier-transform-limited 1.5-ns pulses (bandwidth <500 MHz) in the wavelength range 435 to 2000 nm with energy of 3.5 mJ at a pump energy of 22 mJ. Continuous scanning over 30 to 100 GHz (depending on wavelength) is demonstrated by recording of the resonance line of the Hg atom at 253.7 nm and a vibrational transition of the CO (2) molecule at 1528 nm.

Toxicological consequences of feeding PCB congeners to infant rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) monkeys

In a study designed to minimize interspecies extrapolation of toxicological data, nine rhesus (Macaca mulatta) and 15 cynomolgus (M. fascicularis) day-old infant monkeys were separated from their dams following parturition and hand-reared using a liquid non-human primate formulation. The infants were randomly divided into a control and a treated group which received a mixture of polychlorinated biphenyl (PCB) congeners analogous to those found in breast milk from Canadian women. The concentration of congeners in the dosing media resulted in each infant receiving a total of 7.5 microg PCB congeners/kg body weight/day. The congeners were added either to the liquid formulation or to corn oil and administered to the back of the monkey's mouth for 20 weeks. Monthly blood and adipose specimens were obtained during the dosing period and then periodically until the monkey was necropsied or taken off test (minimum of 66 weeks on test) for congener analysis. Parameters such as body weight, formula consumption, tooth eruption, somatic measurements, haematology and serum biochemistry were monitored throughout the study. In addition, a qualitative evaluation of the absorption and depletion of the various congeners was undertaken as was an immunological evaluation. For the monitored parameters, very few differences were found to be statistically significant. For the immunological parameters, the only statistically differences found were a reduction over time for immunoglobulins M and G antibodies to sheep red blood cells (cyno, P = 0.025; rhesus, P = 0.002) and a treatment-related reduction in the levels of the HLA-DR cell surface marker (mean percent, P = 0.016; absolute levels, P = 0.027). There were some qualitative differences regarding absorption and depletion rates for the various congeners, but it could not be definitely ascertained whether these differences were due to species differences or dosing mode. However, statistically significant differences were found for treatment (P = 0.0293) as well as for species and vehicle regarding the concentration of PCB in blood (species;--P = 0.0399; treatment--P = 0.0001) and adipose tissue (species--P = 0.0489; treatment--P = 0.0001).

Dissection of the fusarium I2 gene cluster in tomato reveals six homologs and one active gene copy

The I2 locus in tomato confers resistance to race 2 of the soil-borne fungus Fusarium oxysporum f sp lycopersici. The selective restriction fragment amplification (AFLP) positional cloning strategy was used to identify I2 in the tomato genome. A yeast artificial chromosome (YAC) clone covering approximately 750 kb encompassing the I2 locus was isolated, and the AFLP technique was used to derive tightly linked AFLP markers from this YAC clone. Genetic complementation analysis in transgenic R1 plants using a set of overlapping cosmids covering the I2 locus revealed three cosmids giving full resistance to F. o. lycopersici race 2. These cosmids shared a 7-kb DNA fragment containing an open reading frame encoding a protein with similarity to the nucleotide binding site leucine-rich repeat family of resistance genes. At the I2 locus, we identified six additional homologs that included the recently identified I2C-1 and I2C-2 genes. However, cosmids containing the I2C-1 or I2C-2 gene could not confer resistance to plants, indicating that these members are not the functional resistance genes. Alignments between the various members of the I2 gene family revealed two significant variable regions within the leucine-rich repeat region. They consisted of deletions or duplications of one or more leucine-rich repeats. We propose that one or both of these leucine-rich repeats are involved in Fusarium wilt resistance with I2 specificity.

Dissection of the fusarium I2 gene cluster in tomato reveals six homologs and one active gene copy

The I2 locus in tomato confers resistance to race 2 of the soil-borne fungus Fusarium oxysporum f sp lycopersici. The selective restriction fragment amplification (AFLP) positional cloning strategy was used to identify I2 in the tomato genome. A yeast artificial chromosome (YAC) clone covering approximately 750 kb encompassing the I2 locus was isolated, and the AFLP technique was used to derive tightly linked AFLP markers from this YAC clone. Genetic complementation analysis in transgenic R1 plants using a set of overlapping cosmids covering the I2 locus revealed three cosmids giving full resistance to F. o. lycopersici race 2. These cosmids shared a 7-kb DNA fragment containing an open reading frame encoding a protein with similarity to the nucleotide binding site leucine-rich repeat family of resistance genes. At the I2 locus, we identified six additional homologs that included the recently identified I2C-1 and I2C-2 genes. However, cosmids containing the I2C-1 or I2C-2 gene could not confer resistance to plants, indicating that these members are not the functional resistance genes. Alignments between the various members of the I2 gene family revealed two significant variable regions within the leucine-rich repeat region. They consisted of deletions or duplications of one or more leucine-rich repeats. We propose that one or both of these leucine-rich repeats are involved in Fusarium wilt resistance with I2 specificity.

Postmortem tissue levels of polychlorinated biphenyls in female rhesus monkeys after more than six years of daily dosing with Aroclor 1254 and in their non-dosed offspring

Polychlorinated biphenyl (PCBs) analyses were made on prenecropsy blood samples and postmortem adipose, liver, kidney, and brain tissues from female rhesus monkeys fed a daily dose of 0, 5, 20, 40, or 80 micrograms Aroclor 1254/kg body weight for approximately 6 years. During this time, the females were bred with non-dosed males. All resulting offspring were nursed for 22 weeks and fed no additional PCBs until they were necropsied at approximately 120 weeks after birth. PCBs were also measured in necropsied infant tissues to determine PCB levels due to intake of PCB-contaminated milk from the dosed dams, in addition to in utero exposure. Polychlorinated biphenyl levels in all tissues of the adult monkeys increased with their dosage. The highest PCB levels were found in adipose tissue and the lowest levels were found in the brain. Polychlorinated biphenyl residues in the cortex of the kidney were lower than in the medulla, while in the brain no appreciable differences were observed between the occipital and frontal lobes. Necropsy tissues of infants from dosed dams contained more PCBs than those nursed by controls, but less than tissues from stillborn infants. Although no differences were observed between PCB tissue levels from monkeys having offspring and those having no offspring, those having a stillborn infant had higher PCB levels in their tissues than those with a viable infant. Similarly, monkeys that were euthanized because of poor health had higher PCB levels in their tissues than those necropsied at the conclusion of the study and showed a dramatic shift from tetra- and hexachlorobiphenyls to penta- and heptachlorobiphenyls in their tissues. The PCB distribution pattern in tissues from a dosed mother/infant pair differed considerably. A larger percentage of heptachlorobiphenyls was found in the infant than in its dam. The adipose/blood PCB ratio in the adult monkeys remained remarkably constant.

Female rhesus monkeys dosed with Aroclor 1254: analysis of polychlorinated biphenyl congeners in dam's milk and in the blood of dams and their offspring before, during, and after gestation

Specific polychlorinated biphenyl (PCB) congeners were measured before, during, and after gestation in the blood of rhesus monkeys, as well as in their milk and in the blood of their infants during lactation, as part of a long-term feeding study to evaluate the toxicology of Aroclor 1254 on pre- and postnatal development of infant monkeys. During gestation a considerable shift from the higher to lower chlorinated biphenyls in the blood was observed in both dosed and nondosed animals. The contribution of penta- and hexachlorobiphenyls in the milk slightly increased with higher dosage. In addition, the percentages of 2,2'3,4,5'-,2,2',4,5,5'-, and 2,3,3',4',6-pentachlorobiphenyls were remarkably lower in the milk of dosed dams than in the originally ingested Aroclor 1254. PCB congener levels in infant blood increased during the lactation period but immediately decreased upon weaning. The lower chlorinated biphenyls virtually disappeared from infant blood after 16 weeks of nursing. Some correlations were observed between PCB congener levels in mother and infant and the congener ratios calculated.

Toxicological consequences of aroclor 1254 ingestion by female rhesus (Macaca mulatta) monkeys. Part 2. Reproduction and infant findings

A group of 80 menstruating rhesus (Macaca mulatta) monkeys were randomly allocated to four similar test rooms (20 monkeys/room) and then randomly allocated within each room to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight. After 25 months of continuous dosing, approximately 90% of the treated females had attained a qualitative pharmacokinetic steady state with respect to the concentration of polychlorinated biphenyl (PCB) in their adipose tissue. Commencing on test month 37, each female was paired with an untreated male until either an impregnation occurred or the 29-month breeding phase of the study was completed. The females continued to receive their daily test dose during mating and gestation. To preclude an infant ingesting the mother's dosing capsule, dosing of the dam was discontinued when a nursing infant was approximately 7 wk old. Treatment was restarted when the infant was weaned at 22 wk of age. At parturition, and every 4 wk until weaning, milk and blood samples were obtained from the dam and a blood sample was obtained from the infant for PCB analysis. When the infant was 20 wk old, immunological testing was initiated and an adipose sample was obtained from the infant and dam for PCB analysis. Subsequently, further adipose and blood samples were obtained from the infant and blood specimens were obtained from the dam for PCB analysis. Concurrently, each infant was subjected to anthropometric measurements and detailed clinical examinations until it was approximately 122 wk old. At 122 wk some of the control and all of the treated infants were killed humanely and autopsied. A statistical analysis of the reproduction data provided evidence for a significant decreasing dose-related trend in conception rates and a significant increasing dose-related trend in foetal mortality. Several comparisons between impregnated and non-impregnated females did not implicate 'age' as a confounding factor regarding these results. The major findings with the infants involved some immunological test differences and mild clinical manifestations of PCB ingestion.

The elimination and estimated half-lives of specific polychlorinated biphenyl congeners from the blood of female monkeys after discontinuation of daily dosing with Aroclor 1254

The levels of thirty polychlorinated biphenyl congeners in the blood of female rhesus monkeys, previously dosed with Aroclor 1254 for over six years, were monitored every two weeks during the first year and monthly during the subsequent two years after dosing was discontinued. Both blood lipid and polychlorinated biphenyl congener levels generally declined during this post dosing period. The percent distribution of the PCB congeners during the post dosing period remained relatively constant with more than half of all polychlorinated biphenyls consisting of the mono-orthochlorine substituted biphenyls. The contribution of the mono-orthochlorine substituted biphenyls was significantly different for one out of three monkeys in two of the three dose groups, during the post dosing period. Half-life, estimations for nine of the congeners ranged from 0.3-7.6 years.

Polychlorinated biphenyl levels in the tissues of exposed and nonexposed humans

Polychlorinated biphenyls (PCBs) are synthetic chemicals, manufactured in volume from about 1929 to the 1970s. Environmental contamination by PCBs has been documented in various substances, including human tissue. PCBs have been measured in human tissue by a variety of analytical methods. PCB levels have been reported as an approximation of total PCB content expressed in terms of a commercial mixture, by identification and quantification of chromatographic peaks, or by qualitative and quantitative characterization of specific congeners. Until recently, the coplanar mono-ortho- and di-ortho substituted PCBs, which are especially toxic and present in significant concentration in humans from industrial countries, had not been measured in human tissues. Examples of various types of commonly used analyses are presented in general population subjects and in persons who experienced special exposure. In this paper, the usefulness of PCB blood determinations following potential exposure is demonstrated, and their application in health studies is illustrated from a number of case studies. Coplanar PCB, mono-ortho-substituted and di-ortho-substituted PCB levels in human blood are presented and compared with polychlorinated dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in the U.S. population. Dioxin toxic equivalents for the two groups of chemicals are calculated and compared. It is found that mono-ortho-substituted and, to a lesser extent, coplanar PCBs, contribute substantially to dioxin toxic equivalents (TEq) in blood from U.S. adults. Because of substantial PCB contribution to dioxin toxic equivalents, total dioxinlike toxicity can only be determined if dioxins, dibenzofurans, and dioxinlike PCBs are measured.(ABSTRACT TRUNCATED AT 400 WORDS)

Temporal changes in some chlorinated hydrocarbon residue levels of Canadian breast milk and infant exposure

Between 1967 and 1986, five national surveys were carried out to determine organochlorine residues in Canadian breast milk. In these surveys the number of samples, their geographic sampling distribution and fat content changed over the years. In addition, the number of samples obtained from younger mothers decreased, while those from older mothers (31-40 years) increased. Total DDTs showed the most consistent decline of all declining residues, while PCBs only decreased after 1982. Levels of oxychlordane and trans-nonachlor remained constant. Ratios of p,p'-DDE/p,p'-DDT gradually increased from 3.1 to 10.0 over the same period of time. With few exceptions, regional trends in residue levels followed those observed for the whole country. Although the number of reported chemicals increased since 1967, this was not necessarily reflected in the total accumulated residues in breast milk. By 1986, the daily intakes of all compounds at 8 weeks of nursing were well below the established acceptable daily intakes.

Determination of polychlorinated biphenyls in postpartum blood, adipose tissue, and milk from female rhesus monkeys and their offspring after prolonged dosing with Aroclor 1254

Analytical and quality control procedures are described for the determination of polychlorinated biphenyls in blood, adipose tissue, and milk from dosed female monkeys and their offspring, as part of a study to measure the toxicological effect of Aroclor 1254 on the pre- and postnatal development of fetus and infant, respectively. Recoveries of polychlorinated biphenyls from fortified blood, fat, and milk of monkeys ranged from 81 to 96%, whereas recoveries from fortified corn oil, used to evaluate routine analysis, ranged from 94 to 108%. The coefficient of variation for triplicate analyses of lipids and polychlorinated biphenyls in blood or adipose tissue or both was less than 10%. Polychlorinated biphenyl levels in blood, milk, and fat rose with increasing dosage. After weaning, when the infants were no longer exposed to polychlorinated biphenyls, their blood levels declined rapidly and approached maternal levels within 40-50 weeks. Approximately 100 weeks after weaning, polychlorinated biphenyl levels in adipose tissue of infants from treated dams reached the background levels of those in the control group.

Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaca mulatta) monkeys. Part 1B. Prebreeding phase: clinical and analytical laboratory findings

A group of 80 menstruating rhesus (Macaca mulatta) monkeys, with an average estimated age of 11.1 +/- 4.1 yr SD were first randomly allocated to four similar test rooms (20 monkeys/room), and then randomly allocated to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight. After 25 months of daily dosing, approximately 90% of the treated females attained a qualitative pharmacokinetic steady state with respect to the concentration of polychlorinated biphenyl (PCB) in their adipose tissue. Subsequently, oestrogen and progesterone concentrations in serum were determined for one complete oestrous cycle and various immunological tests were conducted, while the monkeys continued to receive their daily dose of PCB. During the prebreeding phase of the study, blood for clinical and analytical monitoring including haematology, serum biochemistry, serum hydrocortisone, serum proteins (alpha 1, alpha 2, beta and gamma-globulins), serum immunoglobulins (A, G and M) and thyroid variables (thyroxine/triiodothyronine (T3) uptake ratio, percentage T3 uptake and free thyroxine index), were obtained monthly, as were specimens to ascertain the concentration of PCB in the blood, adipose tissue and faeces. Major findings among treated monkeys included the following: changes in haematology (decreased erythrocyte count, haematocrit, reticulocyte count, and mean platelet volume), serum biochemistry (decreased cholesterol and total bilirubin), immunotoxicity (decreased antibody production to sheep red blood cells and alterations in the percentage of T helper and T suppressor cells) and pathology (the number of regions of sebaceous gland lobules per unit of histological length was significantly reduced). These effects were observed at PCB doses lower than those previously reported for non-human primates.

Levels of chlorinated hydrocarbon residues in Canadian human breast milk and their relationship to some characteristics of the donors

A total of 412 breast milk samples from women in all provinces of Canada were analysed for polychlorinated biphenyls, eight chlorinated benzenes, 2,3-dichloronaphthalene, Mirex, alpha, beta, gamma and delta hexachlorocyclohexane, alpha and gamma chlordane, oxychlordane, transnonachlor, p,p'-DDT and some analogues, heptachlor epoxide, dieldrin and octachlorostyrene. No delta-hexachlorocyclohexane, heptachlor or aldrin were found in any of the samples, while median levels of the 1,2,4- and 1,3,5-trichlorobenzene, 1,2,3,4- and 1,2,3,5-tetrachlorobenzenes, gamma chlordane, o,p'-DDT and octachlorostyrene were all less than the minimum detectable level (MDL). All other compounds were present at median levels ranging from < 0.1 to 7.2 ng/g whole milk, but did not occur in all samples. Di to tetrachlorobenzenes, except 1,2,4-trichlorobenzene, 2,3-dichloronaphthalene and alpha-chlordane were observed in < 50% of the samples. From 1967 to 1986 a steady decline of hexachlorobenzene, gamma-hexachlorocyclohexane, DDTs, heptachlor epoxide and dieldrin was observed in Canadian breast milk. In addition, a decrease in some chlorinated benzenes, gamma-hexachlorocyclohexane and PCBs was also observed between 1982 and 1986. Levels of oxychlordane and trans-nonachlor remained constant. Canadian breast milk contamination appears to be one of the lowest among the industrialized nations. Regional and provincial differences in residue levels appeared minimal, although more often samples from Quebec and British Columbia had higher levels of some contaminants, such as oxychlordane, than samples from other provinces. No relationship was found between maternal age and residue levels, but some contaminants, such as PCBs, were significantly higher in the milk of mothers who breastfed their first child as compared to multiparous mothers. Breast milk residue levels were not related to fish consumption.

Assessment of human exposure to chemical contaminants in foods

One of the most important factors in assessing risk to human health from potentially harmful chemicals in foods is the availability of good data on the exposure of the public to such substances. The means of acquiring these data generally involves monitoring programmes using appropriate sampling procedures and reliable analytical methods for measuring the compounds of concern in a variety of substrates. Two approaches are generally employed: a biological monitoring programme which measures substances in human fluids and tissues, and a food analysis monitoring programme, preferably a total diet study, wherein food is prepared for consumption prior to analysis. The choice of approach to use and chemicals to monitor depend on the situation within a particular country. The analysis of food has the advantage of short term impact since problems can be identified relatively quickly and control measures established. Biological monitoring on the other hand tends to indicate both accumulated and current exposure from all sources, including air, water and food. In Canada both approaches have been used for a number of years with major surveys of human milk and adipose tissue, and the total diet study, being conducted approximately every five years. Details of these programmes together with some of the pertinent findings are presented.

Levels of specific polychlorinated biphenyl congeners in fatty foods from five Canadian cities between 1986 and 1988

A total of 155 fatty food composites from five major Canadian cities were analysed for 36 selected polychlorinated biphenyl (PCB) congeners. Total PCB congener levels of more than 1 ng/g (wet weight) were found in fresh water fish, canned fish, butter, marine fish and cheese, with fresh water fish (18.7 ng/g) containing 5 to 10 times more total PCBs than the other four food commodities. Milk (2%), cooking oils/salads and canned meat soup contained less than 0.1 ng/g (wet weight). The observed total PCB residue levels in fatty foods were well within the Canadian guidelines for fish, dairy products, poultry, eggs and beef. The most predominant congeners found in fish, butter, cheese, meat and poultry were the 2,2',4,4',5-, 2,3',4,4', 5-pentachloro-, 2,2',3,4,4',5'-, 2,2',4,4',5,5'-hexachloro- and 2,2',3,4,4',5,5'-heptachlorobiphenyls. The predominant congener pattern was not always evident in other dairy products (e.g. ice cream) and processed foods (e.g. canned meat soup). An attempt was made to relate the intake of PCB congeners from fatty foods with congener levels found in adipose tissue of Canadians. The estimated daily intake of some specific PCB congeners from fatty foods, in most cases accounted for more than half the total deposit of these congeners in adipose tissue of Canadians.

A pilot study on the effects of Aroclor 1254 ingestion by rhesus and cynomolgus monkeys as a model for human ingestion of PCBs

A pilot study using female cynomolgus (Macaca fascicularis) and female rhesus (Macaca mulatta) monkeys was conducted to study the effects of chronic ingestion of polychlorinated biphenyls (PCBs). Four control and four treated monkeys of each species received an apple juice-gelatin mixture containing 0 and 280 micrograms Aroclor 1254/kg body weight/day, respectively, 5 days/wk. The cynomolgus monkeys, which were mature monkeys with a poor breeding history, were treated for approximately 55 wk, while the rhesus monkeys, which were just attaining sexual maturity, were treated for approximately 120 wk. After 38 wk on test, the treated and control rhesus monkeys were mated with untreated males. The clinical signs resulting from the Aroclor 1254 ingestion were similar for both species, and the time of onset after initiation of treatment was not appreciably different between the two species. Several treatment and interspecies differences were found with regard to the haematological and serum biochemistry parameters monitored, but age differences between the two species may have contributed to these findings. Periodic analysis of adipose tissue, blood and faecal specimens for PCBs suggested that the rhesus monkey retained more of the ingested PCB than did the cynomolgus monkey. Following mating, all of the treated rhesus monkeys aborted within 30-60 days after becoming pregnant, while all of the control monkeys had viable offspring.

Trends in the levels of some chlorinated hydrocarbon residues in adipose tissue of Canadians

Trends in the levels of hexachlorobenzene, hexachlorocyclohexanes, oxychlordane, t-nonachlor, heptachlor epoxide, dieldrin, DDTs and polychlorinated biphenyls in adipose tissue of the Canadian population were followed from 1969 to 1985. Residues of lindane, dieldrin and p,p'-DDT continuously and significantly (P<0.025) decreased during that time, coinciding with restrictions on their use. Other residues also decreased significantly between 1969 and 1985, although not always continuously, while t-nonachlor levels did not change significantly since 1972. In general no consistent and/or significant differences were observed between the sexes, but in some instances differences were found for a particular residue in a given year. Three arbitrarily chosen age groups (0-25; 26-50 and > or =51 years) showed a downward trend in residue levels with time. The results of the surveys also indicate an increase in adipose tissue burden of chlorinated hydrocarbons with age, but this increase became apparently less significant with increasing age.

The effect of long-term feeding of Aroclor 1254 to female rhesus monkeys on their polychlorinated biphenyl tissue levels

The result of feeding Aroclor 1254 to female Rhesus monkeys at doses of 0, 5, 20, 40 and 80 micrograms/kg body weight/day for a period of 37 months was measured in terms of polychlorinated biphenyl (PCB) levels in blood, adipose tissue, and feces. PCB concentrations in whole blood increased more rapidly during the first 10 months of the study than in the remaining 27 months for all dose groups. On a blood-lipid basis, however, another rapid increase in PCB levels was observed after 27 months of dosing, which could not be explained on the basis of an overall decrease in blood-lipid levels. Concentrations in adipose tissue and adipose fat increased continuously during the 37 months of dosing. These observations were reflected in the ratio profiles of PCB levels in blood/PCB levels in adipose tissue, which remained relatively static between the 2nd and 27th month of continuous feeding. Expressing the data in terms of relative concentrations (concentration/dose) suggests that bio-accumulation or retention of PCBs may be dose-dependent, particularly for adipose tissue, with the higher relative concentrations of the lowest dose group significantly (p less than 0.001) different from all other dose groups. Similarly, the limited feces data available suggests a dose-dependent PCB absorption. The distribution of PCB peaks in the gas chromatographic elution pattern of all analyzed substrates showed considerable deviation from that of administered Aroclor 1254. Only minor changes in the percent distribution pattern were observed between dose groups.

Determination of some specific isomers of polychlorinated biphenyl congeners in fatty foods of the Canadian diet

A total of 93 fatty food composites from the cities of Ottawa and Halifax (Canada) were analyzed for 34 selected isomers of polychlorinated biphenyls (PCBs). All fatty foods contained some PCB isomers with the 2,3,4,2',4',5'- and 2,4,5,2',4',5'-hexachlorobiphenyls present in all samples, except in skim milk and some dehydrated soups. The overall lowest PCB residues of all food commodities were found in skim milk, lamb, margarine and soups. Among the dairy products the highest PCB isomer levels were found in cheese and butter. The sum of all PCB isomers in these two commodities gave residue levels on a wet basis of 2.0 and 3.4 ng/g respectively. In the meat, fish and poultry class the highest specific PCB isomer levels were found in fish, especially freshwater fish, which contained a total of 21.0 ng PCB/g fish. In addition 28 out of the 34 selected PCB isomers were present in freshwater fish. Residue levels in canned fish were the second highest of all food commodities. The observed total PCB residue levels were below the Canadian guidelines for fish, dairy products, poultry, eggs and beef. A comparison of the percentage distribution of PCB isomers in fatty foods and human milk was difficult to evaluate due to the large variation of the fatty food data. However out of 31 PCB isomers reported in fatty foods, 25 were also found in human milk, although not to the same extent.

Levels and trends of chlorinated hydrocarbon contaminants in the breast milk of Canadian women

A total of 210 breast milk samples from 5 different regions across Canada were analyzed for polychlorinated biphenyls (PCBs), hexachloro-1,3-butadiene, ten chlorinated benzenes, two chlorinated naphthalenes, Mirex, photomirex, alpha, beta and gamma hexachlorocyclohexane, alpha and gamma chlordane, oxychlordane, trans-nonachlor, p,p'-DDT and some analogs, heptachlor epoxide, dieldrin and octachlorostyrene. There was no evidence for the presence of hexachloro-1,3-butadiene, Mirex, octachlorostyrene, chlorinated naphthalenes or tetrachlorobenzenes in the breast milk. Residues of other compounds were found in all samples, except 1,2-dichlorobenzene, gamma hexachlorocyclohexane, alpha and gamma chlordane and p,p'-TDE, which were less frequently observed, while o,p'-DDT was only found in approximately one quarter of all samples. Since 1967, a steady decline in heptachlor epoxide, dieldrin and p,p'-DDT and related residues is apparent. At the same time however, there is an apparent increase in PCB residue levels since 1970. This apparent increase should be viewed with some caution, since much of this increase might be attributed to better sampling and analytical techniques. Residue levels of breast milk in Canada were similar to those found in other industrial nations. Regional differences in residue levels appeared to be minimal.

A pilot study in adult rhesus monkeys (M. mulatta) treated with Aroclor 1254 for two years

Aroclor 1254, at a dose level of 280 micrograms/kg body weight equivalent to 200 micrograms/kg/day, was given 5 days per week to rhesus monkeys over a 27 to 28 month period. Terminal clinical signs of varying severity included fingernail detachment, exuberant nail beds, weight loss, stomatitis and normocytic anemia. At necropsy the bone marrow was hypocellular with increased M:E ratio and cytoplasmic vacuoles in erythroid precursor cells. Histopathologic lesions included dilatation of the tarsal gland ducts, atrophy or absence of splenic and lymph node germinal centers, bone marrow depletion, gingival erosion and ulceration, moderate mucinous hypertrophic gastropathy with cystic dilatation of occasional gastric glands, hepatocellular enlargement and necrosis, hypertrophy of biliary duct epithelium, hyperplasia of biliary ducts, hypertrophy of the gall bladder epithelium, and an equivocal increase in the number of lysosomes in thyroid follicular epithelial cells. PCB tissue concentrations were lowest in brain and highest in blood. The results suggest that severe potentially fatal PCB toxicity can develop in rhesus monkeys following ingestion of Aroclor 1254 at 200 micrograms/kg/day for a period of 27 months or longer.

Polychlorinated biphenyl (PCB) toxicity in adult cynomolgus monkeys (M. fascicularis): a pilot study

Aroclor 1254 and Aroclor 1248, at doses of 11.7 and 4.7 mg/kg body weight (equivalent to 5 and 2 mg/kg/day), were given 3 days per week to groups of cynomolgus monkeys, and caused weight loss, fingernail loss, facial edema, epiphora, and death. Blood and adipose tissue PCB concentrations rose with the length of treatment. Tissue concentrations in blood, adipose tissue, liver and kidneys were highest in monkeys treated with Aroclor 1254, reflecting dose differences. There was considerable variation, both within and between groups, in hematologic responses to PCB treatment. Aroclor 1254-treated monkeys had depressed and weakly responsive erythropoiesis. Aroclor 1248-treated monkeys had active but ineffective or depressed erythropoiesis with severe macrocytic or moderate normocytic anemia. Biochemical determination of blood serum constituents revealed treatment and time-related trends towards hypoalbuminemia and increased alkaline phosphatase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, lactic dehydrogenase, cholesterol, triglycerides, total bilirubin and direct bilirubin values. Pathologic lesions common in both Aroclor groups were dilatation of meibomian glands duct; mucinous hyperplasia of the gastric mucosa; atrophy and loss of germinal centers in the splenic and other lymphoid follicles; enlargement, fatty degeneration, and necrosis of hepatocytes; bile duct and gall bladder epithelial cell hypertrophy and hyperplasia; and thyroid aberrations in follicular cell size and number of intracytoplasmic lysosomes. Lesions seen exclusively in an Aroclor 1254-treated monkey were widespread mucinous metaplasia and hyperplasia of the fundic mucosa. The results suggest that in general, cynomolgus monkeys may be more refractory or less susceptible to PCB toxicity than rhesus monkeys and, that Aroclor 1248 may be more toxic than Aroclor 1254.

The determination of polychlorinated biphenyl in small samples of monkey milk and tissues. II. Extraction efficiency

The extraction efficiency of benzene, toluene, dichloromethane, acetone:hexane and chloroform:methanol with respect to lipids and polychlorinated biphenyls was investigated using small samples of monkey adipose tissue, liver, kidney, brain, skin, feces and milk. The most efficient solvents were: acetone:hexane and chloroform:methanol for brain, feces, kidney, liver and milk; acetone:hexane and dichloromethane for adipose tissue; acetone:hexane and toluene for blood and dichloromethane for skin tissue. Within these solvent pairs acetone:hexane was the most outstanding with respect to an average of 90% PCB recoveries from fortified samples in the range of 0.02-2 ppm. In addition, a comparison was made between the lipid determination before and after Florisil column chromatography. Only adipose and blood lipids were sufficiently recovered from Florisil to make a lipid determination after chromatography feasible.

Experiences in human milk analysis for halogenated hydrocarbon residues

Factors affecting the different stages of human milk analysis for halogenated hydrocarbon residues are explored. The variation in milk fat during breast feeding and its consequences for sampling are outlined. Extraction efficiency is discussed in terms of fat content, residue recovery and sample size. The importance of clean-up procedures is illustrated by the removal of fat from the extract and unknown contaminants from adsorbents. Polychlorinated biphenyls (PCBs) are partially separated from other halogenated hydrocarbon residues on a Florisil-silicic acid column. Both packed and capillary gas chromatographic columns can be used for identification and quantification of residues in human milk. Confirmation by chemical derivation and mass spectrometry is illustrated by the perchlorination of PCBs and PCB isomer distribution respectively. Fortification of samples and the use of a collaborative study are described as a means for method evaluation.

The determination of polychlorinated biphenyl in small samples of monkey milk and tissues. I

The feasibility of analysing less than or equal to 5 ml blood and 1 ml monkey milk samples for polychlorinated biphenyls (PCBs) was tested by fortification of similar size human blood and milk samples with Aroclor 1260 at the 1, 5, 10 and 10 ng/g level, respectively. Recoveries were 71, 82 and 89% for blood and 95% for milk. Recoveries of > 90% were obtained, when 100 mg samples of monkey liver, kidney and adipose tissue were fortified with Aroclor 1254 at the 0.2, 0.5 and 1 microgram/g level. The methodology was then applied to blood, collected from monkeys receiving Aroclor 1254 at definite intervals of dosing. The initial PCB level rose from 2.2 to 4.5 ng/g after 120 days. Monkey milk analysed at different days of lactation showed little variation in the PCB content on a whole milk basis. The peak height ratios varied among the substrates and with those of standard Aroclor 1254.