Some aspects of cadmium flow in the U.S

Brain tumor epidemiology: consensus from the Brain Tumor Epidemiology Consortium

Epidemiologists in the Brain Tumor Epidemiology Consortium (BTEC) have prioritized areas for further research. Although many risk factors have been examined over the past several decades, there are few consistent findings, possibly because of small sample sizes in individual studies and differences between studies in patients, tumor types, and methods of classification. Individual studies generally have lacked samples of sufficient size to examine interactions. A major priority based on available evidence and technologies includes expanding research in genetics and molecular epidemiology of brain tumors. BTEC has taken an active role in promoting understudied groups, such as pediatric brain tumors; the etiology of rare glioma subtypes, such as oligodendroglioma; and meningioma, which, although it is not uncommon, has only recently been registered systematically in the United States. There also is a pressing need for more researchers, especially junior investigators, to study brain tumor epidemiology. However, relatively poor funding for brain tumor research has made it difficult to encourage careers in this area. In this report, BTEC epidemiologists reviewed the group's consensus on the current state of scientific findings, and they present a consensus on research priorities to identify which important areas the science should move to address.

Cadmium and prostate cancer: a critical epidemiologic analysis

Laboratory data implicate cadmium as a prostate carcinogen. However, epidemiological studies concerning the association between cadmium and prostate cancer are inconclusive. This article reviews the epidemiological literature on cadmium and prostate cancer with a special focus on highly exposed occupational cohorts. We searched the MEDLINE database from 1966 to 2002 for articles on cadmium and prostate cancer. All published analytical and descriptive studies that included relevant data were reviewed. In addition, we reviewed the experience of cohorts highly exposed to cadmium in nickel-cadmium battery plants. Of 4 descriptive studies, 3 reported a positive association between cadmium and prostate cancer. Of 10 case-control studies, 5 (50%) reported a positive association. Of 11 cohorts studies, 3 (33%) found a positive association. Finally, 4 studies on cohorts exposed in occupational nickel-cadmium batteries were identified and analyzed. The summary score of the standardized mortality ratios (SMRs) was weakly but not significantly positive 126 (95% confidence interval C.I.: 83-184). In contrast to laboratory studies, epidemiological studies do not convincingly implicate cadmium as a cause of prostate cancer. Future epidemiological studies that attempt to resolve the discrepancy between laboratory and epidemiological studies of cadmium carcinogenesis may benefit from incorporating biological measures of cadmium exposure.

Overview of analysis of carcinogenic and/or mutagenic metals in biological and environmental samples. I. Arsenic, beryllium, cadmium, chromium and selenium

One of the most dangerous and pernicious forms of pollution arises from the potential mobilization of a spectrum of toxic trace metals and metalloids in our environment. Among the most important elements in this regard are arsenic, beryllium, cadmium, chromium and selenium whose adverse toxic effects are now well recognized including their carcinogenicity and/or mutagenicity. These agents (and their derivatives) can be widely dispersed throughout the environment as a result of fossil fuel combustion, industrial and agricultural processes and natural processes. The trend for the immediate future appears to be of greater exposure to these metals not only as a result of generally increased usage patterns but also because of prospective enhanced use of fossil fuels for space heating and electricity generation. In order to more readily evaluate trends of human exposure as well as the toxicity, bioavailability, bioaccumulation and transport of these elements, sensitive analytical procedures are required for the determination of their various oxidation states (as well as their organic derivatives) in complex matrices such as those found in both environmental and biological samples. Hence, the principal objective of this overview is to highlight the more recent trends and state-of-the-art methodologies for the determination of arsenic, beryllium, cadmium, chromium and selenium (in their various forms) in environmental compartments such as air, water, soil and in human tissues (primarily blood, urine, and milk). Techniques to be discussed primarily include atomic absorption spectrometry, neutron activation analysis, gas chromatography, differential pulse polarography and electrochemical analysis. The importance of quality control and differentiation according to speciation will also be stressed.

Effect of cadmium on the immune response in rats

Adult male inbred Wistar rats were given a subtoxic dose of cadmium (25 ppm) orally for 4 weeks prior to and during immunization with sheep erythrocytes (E). The control group received tap water during the experimental period. No difference in the antibody response to E was found between the two groups. Mononuclear peripheral blood cells from experimental and control rats were stimulated with concanavalin A (Con A). The experimental rats had received 25 ppm Cd in the drinking water from weaning until sacrifice at 15 weeks of age. There was no difference in [3H]thymidine incorporation between the cells of the experimental group and those of the control group. Addition of Cd at very low concentrations to the cultures significantly depressed the [3H]thymidine incorporation of the cells from both groups of rats. Thus, a subtoxic dose of Cd apparently had no effect on the in vivo immune response in rats.

A prospective atmospheric emission inventory for cadmium--the European community as a study area

The quantities of cadmium emitted to the atmosphere from natural and human sources have been estimated for the member states of the European Community, allowing the construction of an atmospheric emission inventory for cadmium at the regional level. A survey of the available emission data was used to calculate an emission factor (g cadmium emitted tonne -1 material consumed or produced) for each source. This value was applied to the most recent consumption or production data for the region to obtain an annual discharge estimate. Predictions of future trends in cadmium emissions from human sources over the next two decades were based on economic forecasts for the process in question. The iron and steel industries and refuse incineration are the two largest sources of airborne cadmium in the region, followed by volcanic action and zinc production. It is forecast that there will be an increase in cadmium emissions over the next two decades due mainly to the iron and steel industries and zinc production. A comparison of the emission estimates obtained in this study with those given in previously published inventories reveal disparities in the source strengths for some processes. In particular, it would appear that cadmium emissions from coal combustion and non-ferrous metal production have been overestimated in some past studies.

Sources of cadmium in the environment

This paper is concerned with quantifying the major sources of cadmium in the European Community and assessing the relative significance of such inputs to the environmental compartments, air, land, and water. The methodology involved identification of potential sources of cadmium, including natural processes, as well as those associated with human activities. This was followed by a review of any emission studies of these processes and subsequent estimation of an emission factor for each source. The emission factor was applied to the most recent production or consumption data for the process in question to obtain an estimate of the annual discharge. The steel industry and waste incineration, followed by volcanic action and zinc production, are estimated to account for the largest emissions of atmospheric cadmium in the region. Waste disposal results in the single largest input of cadmium to land; the quantity of cadmium associated with this source is greater than the total from the four other major sources--coal combustion, iron and steel production, phosphate fertilizer manufacture and use, and zinc production. The characterization of cadmium inputs to aquatic systems is incomplete but of the sources considered, the manufacture of cadmium-containing articles accounts for the largest discharge, followed by phosphate fertilizer manufacture and zinc production.

Sources, transport and alterations of metal compounds: an overview. I. Arsenic, beryllium, cadmium, chromium, and nickel

An overview is presented of the current state of knowledge of the salient aspects of the sources, transport, and alterations of arsenic, beryllium, cadmium, chromium, and nickel. This information is considered vital for a better assessment of the scope of potential human hazard to these ubiquitous toxicants and their compounds. Stress is focused on both natural and industrial activities, particularly on the latter's projected trends. Increasing use patterns per se of most of these metals, as well as aspects of waste disposal and the anticipated increased combustion of fossil fuels for power generation and space heating (particularly in the United States), are major causes of potential health concern. Additionally, attention is drawn to the need for increased research to fill the gaps in our knowledge in these vital areas, all in the hope of permitting a more facile identification and quantification of the potential hazard to exposure to these agents.