The BOR syndrome and renal agenesis-prenatal diagnosis andfurther clinical delineation

This is the first report of prenatal diagnosis of a fetus with brachio-oto-renal dysplasia (BOR) syndrome with right-sided renal agenesis and severe left hypoplasia. The father of this fetus had malformed external ears, a left-sided preauricular pit and branchial cyst, and bilateral mild to moderate deafness without a demonstrable renal anomaly. This family highlights the variable expressivity seen in the autosomal dominant BOR syndrome, the importance of genetic counselling for families with BOR syndrome, and the aetiologic heterogeneity of renal agenesis.     

Prenatal diagnosis in Canada — 1990: A review

This paper presents the results of a detailed study of the genetic prenatal diagnostic services available in Canada in 1990. All 22 genetic centres offering prenatal diagnostic services as well as the 64 laboratories processing samples were surveyed. Data were collected from each to determine what testing was being done, how many women were being tested, for what conditions, and with what outcomes. Also, data on the 35 formal outreach sites were collected. The statistics presented are for the 1990 calendar year. This survey was conducted for the Canadian Royal Commission on New Reproductive Technologies.     

Vitamin and thyroid status in arctic grayling (Thymallus arcticus) exposed to doses of 3,3',4,4'-tetrachlorobiphenyl that induce the phase I enzyme system

Induction of phase I biotransformation enzymes is recognized as a hallmark response in fish exposed to coplanar PCBs. Depletions of vitamins A and E and disrupted thyroid hormone and glandular structure secondary to this induction have not yet been examined in an arctic fish species. Arctic grayling were exposed to a single oral dose of 0 (control), 10, 100 or 1000 ng 3,3',4,4'-tetrachlorobiphenyl (TCB) g(-1) bodyweight, a contaminant found in most arctic fish. After 30 and 90 days of exposure, TCB concentrations in tissues, hepatic phase I activity (as ethoxyresorufin-O-deethylase (EROD)), plasma and tissue vitamin A and E concentrations, plasma thyroid hormone levels and thyroid glandular structure were examined. Total plasma osmolality, as an indicator of overall fish health was also monitored. TCB recovery in tissues was low and extremely variable, making comparisons between intended dose groups inappropriate. Therefore, correlation analysis between actual recovered TCB concentrations and biochemical responses was employed. Hepatic EROD activity correlated strongly with liver TCB concentrations. Liver concentrations of vitamin A were altered as a function of TCB concentrations and EROD activity, but plasma vitamin A status was not affected. Vitamin E was depleted by TCB accumulation in blood and EROD induction in liver of males only at 90 days postexposure. Thyroid hormones status and glandular structure were not affected by the short duration TCB exposures used in this experiment. TCB concentrations were correlated with an elevation in plasma osmolality. Results from this experiment indicate that the vitamin status and osmoregulation of arctic grayling exposed to TCB can be compromised. Further studies of field populations exposed to this type of contaminant are warranted.     

Accumulation of bis(tributyltin) oxide by the mud crab, Rhithropanopeusharrisii

Accumulation of ¹⁴C labelled bis(tributyltin) oxide (TBTO) by the mud crab, $\text{Rhithropanopeus}$$\text{harrisii}$, was determined through short-term exposure to labelled water and food. The potential for trophic accumulation during chronic low level exposure is emphasized.     

Effects of organic acids on adsorption of lead onto montmorillonite,goethite and humic acid

Adsorption isotherms for Pb onto six soil components (quartz, feldspar, kaolinite, montmorillonite, goethite and humic acid) were studied. The influence of pH, EDTA and citric acid on the adsorption of Pb onto montmorillonite, goethite and humic acid were considered. Results indicate that the experimental data fit the Langmuir Adsorption Isotherm. The adsorption capacity for Pb at pH 6 was found to be in the order: humic acid (22.7 mg g(-1)) > goethite (11.04 mg g(-1)) > montmorillonite (10.4 mg g(-1)) > kaolinite (0.91 mg g(-1)) > feldspar (0.503 mg g(-1)) > quartz (0.148 mg g(-1)). Generally, the amount of Pb adsorbed onto montmorillonite, goethite and humic acid decreased with increasing concentrations of EDTA and citric acid and with increases in alkality. However, there were two exceptions: (1) addition of citric acid increased the amount of Pb adsorbed onto humic acid; and (2) the amount of Pb adsorbed onto goethite decreased with increasing pH in the presence of EDTA. Some mechanisms involved in the adsorption reactions are discussed.     

Background levels of non-ortho-substituted (coplanar) polychlorinated biphenyls in human serum of Missouri residents

This study characterizes the levels of polychlorinated biphenyls (PCB) congeners PCB 77, PCB 81, PCB 126, and PCB 169, in a group of 150 men and women with no documented exposure to PCBs. Its purpose is to provide current referent levels of coplanar PCBs in Missouri residents and to compare those levels to levels reported in the literature from the United States and other countries. Although this study used an extensive questionnaire assessing potential sources of exposure, no positive relations were found between these exposure sources and participants' PCB levels. The PCB levels for the four congeners measured were lower than any reported in the literature. PCBs 126 and 169 are only two of the dioxin-like congeners; however, their contribution makes up 11% of the total TEQ. Age was significantly related to PCB 126 and PCB 169. For every one-year increase in age, both PCB congeners increased by approximately 0.4 parts per trillion (ppt). There was no gender difference for PCB 126; however, PCB 169 levels were 3 ppt higher in males than females.     

Exposure efficiency: concept and application to perchloroethylene exposure from dry cleaners

Standard approaches for computing population exposures due to specific sources of air pollutants are relatively complex. In many cases, more simple and approximate methods would be useful. This paper develops an approach, based on the concept of exposure efficiency, that may be used for estimating the impact of a source (or source class) on the integrated population exposure. The approach is illustrated by an example, which uses the concept of exposure efficiency to examine the impact of perchloroethylene emissions from dry cleaners in the United States. The paper explores the geographic variability of exposure efficiency by evaluating it for each of 100 randomly selected dry cleaners. For perchloroethylene, which has a long atmospheric residence time, the site-to-site variability in exposure efficiency is found to be relatively small. This suggests that simple exposure assessments, based on generic distributional characterizations of exposure efficiency, may be used in risk assessments without introducing appreciable uncertainty. For many compounds, like perchloroethylene, the uncertainty inherent in the estimation of cancer potency or source emissions would dominate these small errors.     

The challenges of marine spatial planning in the Arctic: Results from the ACCESS programme

Marine spatial planning is increasingly used to manage the demands on marine areas, both spatially and temporally, where several different users may compete for resources or space, to ensure that development is as sustainable as possible. Diminishing sea-ice coverage in the Arctic will allow for potential increases in economic exploitation, and failure to plan for cross-sectoral management could have negative economic and environmental results. During the ACCESS programme, a marine spatial planning tool was developed for the Arctic, enabling the integrated study of human activities related to hydrocarbon exploitation, shipping and fisheries, and the possible environmental impacts, within the context of the next 30 years of climate change. In addition to areas under national jurisdiction, the Arctic Ocean contains a large area of high seas. Resources and ecosystems extend across political boundaries. We use three examples to highlight the need for transboundary planning and governance to be developed at a regional level.