Contaminants future trends

To describe the future trends of POP contamination in the European atmosphere... 

Some recent developments and future trends in international regulation of chemical contaminants in food are discussed in section 12.5. It is attempted to foresee some issues that could be of interest and concern for food scientists and legislators dealing with contaminants in food in the early part of the new millennium. Certainly, persistent organic pollutants, many of which are chlorinated hydrocarbons, and some of which have been used in the past and in fact may still be used in parts of the world as pesticides, will be among those issues of justified concern. 

Although the magnitude of contamination by BTs in coastal waters of Indonesia is low, and no immediate public health problems could be seen, increasing levels of BTs contamination in recent years still causes concern. Information concerning organotin contamination and its potential effects on the ecosystems in Indonesia are still scarce. Continuous monitoring studies are required to observe future trends and to delineate toxicological implications. 

However several POPs, particularly the OCPs and dioxins, remain at low levels in the Australian environment and several remain persistent at low levels in body fats and fluids of Australians. The levels reflect the past use and persistence of OCPs in the Australian environment, contamination of the food chain and the capacity of the body to metabolise and store in body fats. The dioxins remain due to the ubiquitous nature of their sources with combustion as a major source and their persistence. Future trends are likely to mean very low-level residues in human fats of DDE, cyclodienes, HCB, HCHs and dioxins in the long term. Their rate of decline will probably depend on removing HCB from chlorinated industrial chemicals and OCPs from the environment (e.g. remediation of contaminated soils) by hazardous waste treatment methods (e.g. physical, chemical and biological degradation or fixation) or secure landfill. 

The latest annual TLV list is contained in the publication Threshold Limit Values and Biological Exposure Indices. This publication should be consulted for future trends in recommendations. The ACGIH TLVs are adopted in whole or in part by many countries and local administrative agencies throughout the world. As a result, these recommendations have a major effect on the control of workplace contaminant concentrations. The ACGIH may be contacted for additional information at Kemper Woods Center, 1330 Kemper Meadow Drive, Cincinnati, OH 45240. 

In relation to future trends of the membrane treatments described in this chapter, they are expected to be applied for medical and research wastes of low-medium activity contaminated with Cs, or other radioisotopes with similar characteristics. Furthermore, membrane treatment has been proved as an efficient and quick treatment in an incident that generates low-medium radioactive wastes. 

ABSTRACT This paper built hydrogeological conceptual model of Luan River region based on hydrogeological conditions obtained by drilling tests. Internationally accepted software Visual Modflow was used in numerical modeling in this area. With well adjusted parameters we established pollution transport model to analyze and predict the future 20a of Luan River groundwater contamination migration trends. 

Over a period of about twenty years the results of surveillance for veterinary drug residues in meat and animal products in the UK have provided reassurance that residues of veterinary drugs occur at very low concentrations and generally at low frequencies. Over this period repeated surveillance and improved communication and awareness of the producer and feed industry has resulted in a downward trend in the level and incidence of residues detected. However, contamination hot spots remain (e.g. animal medicated feed) and will continue to be monitored in the future. In addition, as new products are introduced into the market they will be evaluated during the licensing process to establish any risk from their residues present in human food. The UK also imports a significant amount of animal-derived food and the presence and risk to the UK consumer of residues in these products must also be considered and appropriate measures taken to protect the UK consumer. 

Tateya, S., Tanabe, S., Tatsukawa, R. (1988) PCBs on the globe possible trend of future levels in the open ocean environment. In Toxic Contaminant in Large Lakes. Vol. II. Sources, Fate and Controls of Toxic Contaminants. Schmidtke, N.W., Ed., pp. 237-281, Lewis Publishers Ltd., Chelsea, MI. 

The Great Lakes have served as a focal point for PCB research. This research has provided an understanding of the processes controlling fate and transport of PCBs, and has led to the development of models than can be applied to other contaminants and water bodies. The processes of atmospheric deposition and net sediment accumulation are described adequately in these models, but the exchange at the sediment-water interface and seasonal depositional patterns need further improvements. While concentrations have declined in air, water and sediments over the last decade, trends in fish indicate a slowing or stopping of such a decline. Thus future research efforts should address the bioaccumulation process and foodweb dynamics, and the physical processes mentioned above. 

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