1998 From: Swedish Environmental Protection Agency
New Research On Environmental PollutantsCommon flame retardants affect the brains of mouse foetuses Animals that were given low doses of dioxin over a long period of time suffered spontaneous abortions and changes in the immune defence. Environmental pollutants in Baltic fish seem to reduce the ability of smokers to become pregnant. These are just some of the around 500 reports in a scientific symposium on environmental pollutants, Dioxin '98 that is held in Stockholm August 17-21. The full title of the meeting is Halogenated Environmental Organic Pollutants, Dioxin'98. It is opened by Swedish Environment Minister and arranged by the Swedish Environmental Protection Agency, Stockholm University, Karolinska Institutet, and the National Chemicals Inspectorate. Dioxins are only one of the groups of chemical substances that will be discussed during the symposium. It will mainly focus on other environmental organic pollutants with potential effects in humans and in wildlife and fish. Two special sessions will cover endocrine disrupting substances. Here is a small day by day selection of interesting reports: Risk Assessment And Management Risk Assessment And Management - Ulf G. Ahlborg Memorial Session Monday afternoon (2-5:20 pm) Low doses over a long period - harmful for e.g. sexual development During recent years, several scientists have reported harmful effects on the immune system, learning capacity and sexual development in various animal species which have been exposed to low doses of dioxins and dioxin-like compounds. Levels are often comparable to those which humans are exposed to. Here is a presentation of several of these studies, which try to imitate real-life exposure of low doses over a long period. Various monkeys have been studied, for example rhesus monkeys which were fed low doses of dioxins in their diet over a long period of time and suffered spontaneous abortion, learning difficulties and changes to the immune system. Sensitive Non-Carcinogenic Effects Of TCDD In Animals Linda S. Birnbaum, U.S. Environmental Protection Agency, Research Triangle Park, USA Fish Good Models For Dioxin Effects Zebra fish and trout are good models for examining the molecular mechanisms of dioxin toxicity even in other animal groups. Like other vertebrates, fish have so called Ah receptors, which are used to measure and understand the effects of dioxins. Experiments with fish, to gain a better understanding of how these receptors convey information, can give us a clearer picture of how dioxins and dioxin-like compounds work.In fish, it is mainly during the early stages that harmful effects from dioxin become evident. Primarily, it is the vascular system in young fish which is affected. Fish As Vertebrate Models Of Dioxin Toxicity Richard E. Peterson, University of Wisconsin, Madison, USA Toxic Pollutants In Northern Environments Northern environments, Tuesday morning (9-12 am)One of the sessions during Dioxin'98 will focus on toxic pollutants in northern environments. Via the atmosphere toxic pollutants travel considerable distances from southern areas and eventually reach the colder northern regions. Toxic Pollutants In Animals In Northern EnvironmentsA large Norwegian study has looked at concentrations of toxic contaminants in animals in northern and polar regions. Among other species, polar bears, porpoises and glaucous gulls have been studied, showing extremely high levels of PCB in some regions. Arctic fox also seems to have higher concentrations than members of the same species further south. In the case of polar bear, it was possible to link pollutants to disrupted hormone levels and lower survival rates among the young, believed to be caused by a large part of toxic pollutants carried over from the mothers during lactation. Environmental Pollutants In Top Predators From The Norwegian Coast And Arctic Janneche Utne Skaare, National Veterinary Institute, Oslo, Norway Persistent Effects In White-Tailed Eagle From suffering the highest concentrations of toxic pollutants among birds of prey in the world, white-tailed eagle living along the Baltic Sea now have clearly lower levels of PCB and DDT. It is still possible to show residual effects in some birds according to new Swedish findings. Female birds born during the worst years in the 1960s and 1970s have inferior eggs than other white-tailed eagles. Fewer eggs are hatched and some show no foetal development at all. The phsyiological reasons for these defects are still not known. Abnormal Dehydration In Eggs Of White-Tailed Eagle In Sweden Björn Helander, Swedish Society for Nature Conservation, and Swedish Museum of Natural History, Stockholm Toxic Pollutants In The Blood Of Inuits - N.B. Human Exposure II Wednesday afternoon (2 - 5 p.m.)A Canadian study shows that Inuits who largely live on fatty fish contaminated with organic pollutants have high levels of OH-PCBs, reaction products of PCB which are retained in the blood. Concentrations in the blood are on average 30 times higher than in other populations (control group), but levels of up to 100 times higher than "normal" can occur. This is the first study to link levels of OH-PCB to age, indicating primarily a relation between PCB levels and age. OH-PCBs are suspected to be hormone disrupting.Analysis Of Hydroxylated Metabolites Of PCBs In Whole Blood From Canadian Inuit Courtney Sandau, Environment Canada, Hull, Canada Epidemiology Tuesday p.m. (2 - 5 p.m.) Female Vietnam War Veterans Exposed To "Agent Orange" Show Poorer Health Female American soldiers exposed to the herbicide "Agent Orange" during the Vietnam War show a number of health problems which are not present in comparable groups not exposed to the herbicide. The problems concern various forms of cancer and reduced fertility. The study compared the women's combat positions with records showing where "Agent Orange" was used. This resulted in an estimation of how large the exposure was for these women."Agent Orange" is a weed-killer containing the most toxic dioxin (TCDD) which was used in large amounts during the Vietnam War as a defoliant. Health Problems Of American Women Veterans Of The Vietnam War Linda Spoonster Schwartz, Yale School of Medicine, Pawcatuck, USA Baltic Fish Causes Reduced Fertility And Lower Birth Weight There seems to be a link between reduced fertility and large consumption of fish from the Baltic Sea, contaminated with organic toxic pollutants such as PCB. This mainly applies to women who smoke more than ten cigarettes a day. However, only a minor link was found between the consumption of Baltic Sea fish and infertility.Another study found that women that grew up in fishing villages on the Swedish east coast, who also frequently eat fish from the Baltic Sea, run an increased risk of having children with low birth weight. Consumption of contaminated fish is one of the major exposure routes of organic pollutants, such as PCB, for people in Sweden. Times To Pregnance And Miscarriages In Women With A High Dietary Intake Of POC-Contaminated Fish Lowered Birthweight Among Infants Born To Women With High Intake Of Fish Contaminated With POC Lars Rylander, University Hospital, Lund, Sweden Hormone Disrupting Chemicals Endocrine Disruption I Wednesday afternoon (2-5 p.m.)Two sessions during Dioxin'98 deal with endocrine disruptive pollutants. Among other things, the thyroid hormone system, which regulates metabolism will be discussed. New Findings Regarding Possible Health Effects Of Common Brominated Flame RetardantsTetrabromobisphenol-A (TBBP-A) is the most widely employed brominated flame retardant. TBBP-A can compete with the thyroid hormone tyroxine - one of the few effects shown for TBBP-A in biological systems. Several other brominated flame retardants can also affect the thyroid endocrine system, and in a more complex way than hitherto believed. In tests on pregnant mice, TBBP-A and other brominated flame retardants have been shown to accumulate in the brains of unborn mice. The same applies to other toxic pollutants, e.g. certain PCBs. This is due to substances passing through blood barriers to the foetus by binding to a carrier protein in the blood. Structure Dependent Multiple Interactions Of PHAHs With The Thyorid Hormone System Abraham Brouwer, Wageningen Agricultural University, The Netherlands Endocrine Disrupting Substances In Men Who Eat Fish A large study has revealed the levels of various endocrine disrupting substances among men of varying ages and dietary habits. Swedish and Latvian men included in the study did not, however, show any direct disturbances in hormone levels. On the other hand, it became evident that several toxic pollutants, e.g. various brominated flame retardants, now appear to be as wide-spread as PCB and DDT in humans, although levels are still low. Dietary Exposure To Persistent Organochlorines And Pituitary, Thyorid And Testosterone Hormone Levels In Male Adults Lars Hagmar, University Hospital, Lund, Sweden Toxic Pollutants As A Cause Of Blood Sugar Disturbances An American study of workers exposed to dioxins has examined the tendency to develop diabetes. Dioxins are believed to influence the thyroid hormone tyroxine, which in turn plays an important role in regulating blood sugar levels. The study showed that workers with a high exposure had higher blood sugar levels than those with low exposure. Among the most exposed workers, a slight increase in the number of diabetes cases was noted. An Evaluation Of Diabetes Mellitus, Serum Glucose, And Thyroid Function Among U.S. Workers Exposed To 2,3,7,8-Tetrachlorodibenzo-P-Dioxin Geoffrey Calvert, National Institute for Occupational Safety and Health, Cincinnati, USA Brominated Flame Retardants Polymer Additives And Monomers, Thursday morning (9-12 am)Dioxin'98 will include a special section for brominated flame retardants, particularly those which contain bromine and resemble toxic pollutants such as PCB and DDT. Flame Retardants Which Cause Behavioural DisturbancesMice which have been exposed to brominated flame retardants PBDE during the foetal period when the brain is rapidly developing, show permanent disturbances in behaviour, memory and learning. These findings are particularly interesting considering the increase of PBDE in human breast milk. Earlier, similar effects have been shown after exposure to various PCBs. Developmental Neurotoxicity Of Brominated Flame Retardants, PBDE And TBBPA Per Eriksson, Uppsala University, Sweden Brominated Flame Retardants In Marine Animals The presence of brominated flame retardants in various whale, seal and dolphin species has been researched. The survey shows an alarming presence of these substances in dolphins and seals. Moreover, brominated flame retardants are still manufactured and tests show that many of them degrade very slowly. The presence of brominated substances in sperm whales, which seek food at great depths, indicates that these pollutants are found at several hundred meters depth in the Atlantic. Polybrominated Biphenyls And Diphenylethers In Sperm Whales And Other Marine Mammals- A New Threat To Ocean Life? Jacob de Boer, DLO - Netherlands Institute for Fisheries Research, Ijmuiden, The Netherlands Brominated Flame Retardants In Breast Milk - NB Human Exposure I And Polymer, Additives And Monomers Two Swedish studies have shown a presence of the brominated flame retardant PBDE in breast milk in Swedish women. A markedly rising trend over the past 25 years has been shown, with levels of PBDE increasing more than 50 times. A link between smoking and increased concentrations of PBDE in breast milk can also be shown. PBDEs In Beast Milk From Primiparous Women In Uppsala, Sweden Koidu Norén, the Karolinska Institutet, Stockholm and Per-Ola Darnerud, the Swedish National Food Administration, Uppsala, Sweden Human Exposure Human Exposure II, Thursday afternoon (2 - 5 p.m.)Army Food Serves Environmental ResearchOne problem in measuring toxic pollutants is the difficulty in assessing whether levels are increasing or decreasing over time. Tests in the environment can be carried out, for example, by analysing core samples containing sediments. But to establish the intake via our food has been difficult. Now, researcher Dwain Winters at the US Environmental Protection Agency has found an interesting solution. He has analysed dioxins and PCBs in meat from almost the entire century, by locating old army food parcels. The oldest sample is a 1908 "Emergency Ration" of beef and ground wheat, one of the first tinned foods available. A total of 14 samples from beef, pork, chicken and a type of bacon snack were taken. The results show that concentrations in food closely follow the development of levels in the environment, with increases until the end of the l960s, when they reached their peak. After that dioxins and PCBs in food have decreased. Trends In Dioxin And PCB Concentrations In Meat Samples Dwain Winters, U.S. Environmental Protection Agency, Washington DC, USA Symposium Highlights Friday morningA panel of representatives from the various seminars will present the most important developments discussed at the conference. What Will Future Environmental Research Look Like? POP/EDC Science: An Interdisciplinary Challenge For The 2000s. An increasingly interdisciplinary approach will be required to tackle the problems of toxic pollutants, according to Ross Norstrom, researcher into toxic pollutants at Environment Canada. For example, studies and models of toxicity and bioaccumulation must include physiological and zoological parameters of the animals studied, in order to be realistic. Regarding substances which will be of interest, he believes that PCB will still be in the forefront during this generation. Moreover, a more complex picture with more non-persistent substances, will force researchers to look for effects in animals at a lower stage in the food chain, since this is where influence can be made. Current studies of long-lived substances, he believes, will focus on work places and other local sources. Ross Norstrom, Environment Canada, Hull, Canada Global Convention On Persistent Organic Pollutants There is on-going international work to find agreement on how to identify new environmentally hazardous persistent chemicals which can be transported long distances by air or water. Bo Wahlström will speak about efforts to build a global convention on persistent organic pollutants. Bo Wahlström, UNEP, Geneva, Switzerland Questions During the symposium you will reach the scientists through the Secretariat, Dixon'98, phone +46-8-16 19 45, fax +46-8-16 49 09. Please ask for: Niklas Johansson, Swedish Environmental Protection Agency, Tel +46 8 698 14 38, [email protected], or Åke Bergman, Stockholm University, Tel +46 8 16 39 97, [email protected]. Press contacts Swedish Environmental Protection Agency: Suzanne Kolare, Tel +46 8 698 16 97, mobile 0708-26 16 97, [email protected] Stockholm University: Agneta Paulsson, +46-8- 16 22 56, [email protected]
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