Pollution problems, plant

Natural pesticides show promise for alleviating the pollution problem. Plants make some of these pesticides for their own protection, and bacteria synthesize others for purposes that are poorly understood. In spite of their promise, however, products based on natural pesticides have been on the market for years without much success, their major drawbacks being high cost and a reputation for unreliability. The present hope is that continuing research can... 

Hori ntalEetort. In 1800, the first commercial zinc process made use of the horizontal retort. In 1980, only three such plants remain because they are not competitive in terms of labor and fuel costs. Furthermore, the dust produced presents a serious pollution problem. Nevertheless, in 1956, the tonnage of zinc produced from horizontal retorts was above that of any previous year. The only remaining operation is in Russia with a capacity of 10,000 annual MT. 

Air pollution problems and labor costs have led to the closing of older pyrometaHurgical plants, and to increased electrolytic production. On a worldwide basis, 77% of total 2inc production in 1985 was by the electrolytic process (4). In electrolytic 2inc plants, the calcined material is dissolved in aqueous sulfuric acid, usually spent electrolyte from the electrolytic cells. Residual soHds are generally separated from the leach solution by decantation and the clarified solution is then treated with 2inc dust to remove cadmium and other impurities. 

In-plant controls are perhaps the best approach to eliminate waste generation and pollution problems, and many times good payback exists on recovery of products lost because of poor process controls. If the production department is responsible for the generation and in-plant control of wastes, this will help ensure that initial standards for water use and process loss are reasonable and that they are maintained (33). 

The predominant air pollution problem of the nineteenth century was smoke and ash from fhe burning of coal or oil in the boiler furnaces of stationary power plants, locomotives, and marine vessels, and in home heating fireplaces and furnaces. Great Britain took the lead in addressing this problem, and, in the words of Sir Hugh Beaver (3) ... 

As the name implies, these operations, if uncontrolled, can cause a serious air pollution problem. The main problem is the odors associated with the process. Examples of such industries are tanning works, rendering plants, and many of the food processing plants such as fish meal plants. In most cases, the emissions of particulates and gases from such plants are not of concern, only the odors. Requiring these industries to locate away from the business or residential areas is no longer acceptable as a means of control. 

The most widespread and persistent urban pollution problem is ozone. The causes of this and the lesser problem of CO and PMjq pollution in our urban areas are largely due to the diversity and number of urban air pollution sources. One component of urban smog, hydrocarbons, comes from automobile emissions, petroleum refineries, chemical plants, dry cleaners, gasoline stations, house painting, and printing shops. Another key component, nitrogen oxides, comes from the combustion of fuel for transportation, utilities, and industries. 

Such sessions often help to bring to the surface those parts of the plant where suspect waste issues or pollution problems are most critical. Such areas of operations are most likely to benefit from an audit and P2 program. 

In general, the main pollution problems associated with surfactants can be summarized as (1) foaming in river and wastewater treatment plants [314,326, 344,348,349,356,357], (2) transformation to bioactive metabolites (i.e., poly-ethoxylated alkylphenols, estrogenic compounds) under aerobic and anaerobic conditions [315,356], and (3) formation of certain cationics which are toxic to microorganisms at high concentrations [356,357]. 

Many deleterious effects have been associated with photochemically polluted air ozone is deflnitely associated with respiratory problems, plant damage, and material damage PAN has deflnitely been associated with plant damage, and some other members of this class of chemical compounds have been associated with eye irritation the hydroxyl radical is considered to be an important factor in the conversion of gas-phase intermediates to end products, such as sulfur dioxide to particulate sulfate the particulate complex is responsible for haze formation and has also been associated with eye irritation and respiratory effects. The aldehydes have been associated with eye irritation. Ozone and PAN themselves do not cause eye irritation. For purposes of control, much more research is needed, in order to relate the laboratory data about the concentrations of these various materials that have significant effects to their formation in the atmosphere from emission and their atmospheric distribution. The lack of convenient measurement methods has hindered progress in gaining this understanding. 

The use of biolc c indicators as an early detection system for severe air pollution episodes or for chronic air pollution problems is of interest to many urban and industrial control officials. Plants served as air pollution detection sterns long before pollution was acknowledged a problem by industry or government. Higher plants serve as useful detection tools, because they develop characteristic symptoms from acute exposure, even though the symptoms are not necessarily specific to cause. Cause and effect can be reliably ascertained, when an air pollution source is identified and symptom patterns are identified within given sensitive species. 

Plants have been used effectively in field surveys to determine the extent and magnitude of pollution problems and in bioassay techniques in conjunction with field surveys. Most general review articles (Table 11-1) treat, to some extent, the use of plants as indicators of air pollution. Went covered plant sensitivities to pollutants and the use of plants as indicators. He stressed the photochemical oxidants and recommended charcoal filtration for greenhouse use. Heck presented a detailed discussion and review of plants as indicators in field surveys and in the bioassay of photochemical problems. Heggestad and... 

Within the past few years, the rate of our understanding of how air pollution oxidants interect with biological systems has accelerated dramatically. This is the result partially of a reasonable level of federal grants and contract funds and partially of cooperative support by local and state agencies of research into specific pollution problems. Research supported by these agencies not only has helped establish an air pollution control policy, it has also helped develop a better scientific understanding of the biological effects of air pollution on man and plants. 

Pollution problems are hardly a new phenomenon, unique to the current century. Indeed, the history of every human culture appears to contain stories of the cavalier way we have treated our waste products. Until quite recently, people simply dumped wastes into the nearest river or lake, open pits, or the surrounding air, without thinking about the possible effects of those products on plants, animals, or their own lives. 

Nuclear energy avoids the mining and pollution problems of traditional fossil fuels, but it also poses contamination and health risks. Do you think governments should build nuclear power plants State your opinion and support it with convincing reasons. 

Mercury None known. Very toxic to fungi and green plants, and to mammals if in sulubie form a cumulative poison in mammals. Serious pollution problems from use of orgartomer-curials as fungicides and from industrial uses of mer-... 

In recent years, acute air pollution problems have been associated with large power plants. Stack discharges depend on the type of power plant. In oil-fired power plants, the emissions are mainly S02 and NOx. In coal-fired operations, emissions include S02, NOx and a variety of radioactive nuclides derived from coal. In nuclear power plants, emissions are limited to small amounts of radioactive fission products. 

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