Cadmium in food production systems: a health risk for sensitive population groups

This paper gives an overview of the cadmium (Cd) situation in agricultural systems and human exposure in Sweden. Cadmium levels in agricultural soils (the plow layer) increase by 0.03% to 0.05% per year. Feed can give substantial contributions of Cd to local agricultural systems. Effects on human kidney function are indicated by some measurements already at today's exposure levels. If food products reach the maximum permissible levels given by the European Union, 10% to 25% of the Swedish population will be exposed to Cd levels above the provisional tolerable weekly intake (PTWI 7 microg Cd kg(-1) body weight). Sensitive groups in the population are individuals with low iron status (mainly women) and kidney disorders. Recent studies indicate that Cd plays a role in osteoporosis and that further research is needed to clarify if Cd is neurotoxic in early developmental stages. Firm actions have to be taken in order to stop a further increase of Cd in agricultural soils. Suggestions for prevention and measures are given in this paper.     

Potential nitrification and denitrification on different surfaces in a constructed treatment wetland

Improved understanding of the importance of different surfaces in supporting attached nitrifying and denitrifying bacteria is essential if we are to optimize the N removal capacity of treatment wetlands. The aim of this study was therefore to examine the nitrifying and denitrifying capacity of different surfaces in a constructed treatment wetland and to assess the relative importance of these surfaces for overall N removal in the wetland. Intact sediment cores, old pine and spruce twigs, shoots of Eurasian watermilfoil (Myriophyllum spicatum L.), and filamentous macro-algae were collected in July and November 1999 in two basins of the wetland system. One of the basins had been constructed on land that contained lots of wood debris, particularly twigs of coniferous trees. Potential nitrification was measured using the isotope-dilution technique, and potential denitrification was determined using the acetylene-inhibition technique in laboratory microcosm incubations. Nitrification rates were highest on the twigs. These rates were three and 100 times higher than in the sediment and on Eurasian watermilfoil, respectively. Potential denitrification rates were highest in the sediment. These rates were three times higher than on the twigs and 40 times higher than on Eurasian watermilfoil. The distribution of denitrifying bacteria was most likely due to the availability of organic material, with higher denitrification rates in the sediment than on surfaces in the water column. Our results indicate that denitrification, and particularly nitrification, in treatment wetlands could be significantly increased by addition of surfaces such as twigs.     

WESTERN WATER RESOURCES: THE DESERT IS BLOOMING,BUT WILL IT CONTINUE?1

ABSTRACT: The arid Southwest of the United States is confronted with increasing water demands and a limited resource. Past efforts to meet water demand have been directed toward development of scarce water resources. While development programs have been successful in stretching available supply, few feasible development options remain. Furthermore, heavy water utilization has affected water quality within drainage basins. It seems likely that water management will play a much more significant role in water resource allocation in the future. This paper will examine water development activity in the Southwest to date. Attention will be given to several of the problems that have arisen. The paper will then examine water management options. Particular attention will be given to water management options being implemented in the State of Arizona.     

Environmental education in the South Pacific: Towards sustainable development

Summary This paper suggests that for environmental education to have any meaning in the South Pacific, the variety of physical and cultural environments must be taken into account. It is not possible, however, for each country to develop its own programme, and thus, a kind of dependent development which is sustainable should be undertaken. Environmental education is much wider than utilising formal educational curricula; it should include the use of the media, the employment of environmental economists, and a continuous sharing of information between those who carry out environmental research and those who design and implement policy.Dr Jenny Bryant is a Senior Lecturer in the Department of Geography at the University of the South Pacific and Chairperson of the South Pacific Action Committee for Human Ecology and the Environment (SPACHEE). This paper was first presented to the 16th Pacific Science Congress in Seoul, Korea in August, 1987. It has been published elsewhere as part of a UNEP Regional Report (Dahl, 1988).     

DUI offenders' perceptions and misperceptions of basic alcohol information

This paper describes the perceptions and misperceptions of basic alcohol and DUI-related information held by two groups of subjects: first-time DUI offenders and multiple-DUI offenders. The results revealed that both samples of subjects were well informed regarding some basic information (e.g., tolerance, elimination of alcohol from the body by the liver, effect of several drinks on increased likelihood of accident) and that the multiple-DUI offenders appeared more knowledgeable on several items (e.g., penalty for refusing breath test, beverage equivalency). These results tend to discredit the knowledge-deficit model of DUI prevention/education/rehabilitation, and an alternative coping skills model is proposed.     

The occurrence of marine Cladocera on the west coast of Sweden

The present paper is based on a 3-year field study of marine Cladocera in the waters off Gothenburg on the Swedish west coast. The group mainly occurred from May to September, when there was a temperature stratification of the waters. The dominant species, Evadne nordmanni Lovén, may occur in large numbers during the entire warm period, both in offshore and inshore waters. The species Podon leuckarti G.O. Sars, P. intermedius Lilljeborg, and Pleopis (=Podon) polyphemoides (Leuckart) occurred separately both in time and space. The occurrence of different species may primarily be regulated by abiotic factors, e.g. temperature and currents, but may also be modified by competition for food between closely related species. During the early summer, the populations of E. nordmanni and Podon leuckarti seem to be comprised of specimens brought in by the sea, while the estuarine species Pleopis polyphemoides seems to be more indigenous within the area.     

Exposure to anti-cancer drugs during preparation and administration. Investigations of an open and a closed system

Systems for the preparation and administration of drugs are designed to ensure that the drug is not contaminated. They do not necessarily consider the work environment for the medical staff and new techniques are therefore desirable. The aim of this work is to compare a new closed system for the preparation and administration of drugs with the traditional technique with regard to airborne emission and surface spillage of drugs. Platinum, determined using adsorptive voltammetry, was used as the tracer for airborne emission. Air samples were collected during the preparation and administration, and the collected platinum on the filters was determined by adsorptive voltammetry. For determination of spills and leakage onto surfaces the radioisotope 99m-technetium was used as a tracer. The radiation from the isotope was determined on protective gloves and bench covers after preparation and administration. The mean airborne emission was 6 ng m(-3) with the closed system and 15 ng m(-3) with the traditional pump technique. The average surface spillage using the closed technique was 0.005 microL. This is significantly smaller than with the traditional technique, which resulted in an average spillage of 64 microL. Our results also show that the dominant part of the leakage is surface spillage. Inexperienced nurses could also adequately handle the closed system.     

Origins and biological accumulation of small plastic particles in fur seals from Macquarie Island

One hundred and sixty four plastic particles (mean length 4.1 mm) recovered from the scats of fur seals (Arctocephalus spp.) on Macquarie Island were examined. Electron micrographs of 41 of the plastic particles showed that none could be identified as plastic pellet feedstock from their shapes. Commonly, such pellets are cylindrical and spherical. Instead, all the 164 plastic particles from the seal scats were angular particles of 7 colors (feedstock particles are normally opaque or white) and could be classified into 2 categories: i) fragmented along crystal lines and likely to be the result of UV breakdown; and ii) worn by abrasion (where striations were clearly visible) into irregular shapes with rounded corners. White, brown, green, yellow and blue were the most common colors. In composition, they came from 5 polymer groups; polyethylene 93%, polypropylene 4%, poly(1-Cl-1-butenylene) polychloroprene 2%, melamine-urea (phenol) (formaldehyde) resin 0.5%, and cellulose (rope fiber) 0.5%. The larger groups are buoyant with a specific gravity less than that of seawater. These small plastic particles are formed from the breakdown of larger particles (fragments). Their origin seems to be from the breakdown of user plastics washed ashore and ground down on cobbled beaches. Certainly most particles (70%) had attained their final form by active abrasion. It is hypothesized that the plastic particles were washed out to sea and then selected by size and consumed by individuals of a pelagic fish species, Electrona subaspera, who in turn were consumed by the fur seals. Thus, the particles were accumulated both by the fish and the seals in the usual process of their feeding.     

粮食生产系统中的镉:对敏感人群的健康威胁

本文概述了瑞典农业系统中镉的状况以及镉的人类暴露状况.农业土壤(耕层)中的镉每年增加0.03%～0.05%.饲料是当地农业系统中镉增加的重要原因.当前暴露水平下已经有一些测量表明人体肾功能受到影响.如果粮食中的水平达到欧盟允许的最大限度,那么10%～25%的瑞典人群暴露的镉水平将超过暂时可容忍的每周摄入量(PTWI,7μg Cd/kg体重).人群中的敏感者是那些低铁状况(主要是女性)和肾紊乱的个体.最近的研究表明镉对骨质疏松症有影响,但还需要进一步的研究来辨别镉是否在早期发展阶段毒害神经.必须采取坚决行动来阻止农业土壤中镉含量进一步增加.本文给出了预防及采取措施的建议.