1,034,456 research outputs found
Contamination
Soil contamination occurs when substances are added to soil, resulting in increases in concentrations
above background or reference levels. Pollution may follow from contamination when contaminants
are present in amounts that are detrimental to soil quality and become harmful to the environment or
human health. Contamination can occur via a range of pathways including direct application to land and
indirect application from atmospheric deposition.
Contamination was identified by SEPA (2001) as a significant threat to soil quality in many parts of
Scotland. Towers et al. (2006) identified four principal contamination threats to Scottish soils: acidification;
eutrophication; metals; and pesticides. The Scottish Soil Framework (Scottish Government, 2009) set out
the potential impact of these threats on the principal soil functions.
Severe contamination can lead to ācontaminated landā [as defined under Part IIA of the Environmental
Protection Act (1990)]. This report does not consider the state and impacts of contaminated land on
the wider environment in detail. For further information on contaminated land, see āDealing with Land
Contamination in Scotlandā (SEPA, 2009).
This chapter considers the causes of soil contamination and their environmental and socio-economic
impacts before going on to discuss the status of, and trends in, levels of contaminants in Scotlandās soils
Marine pollution hazards related to agriculture
For several centuries, agricultural activity (arable farming and livestock raising)
has developed in harmony with the environment. Farmers produced
what nature allowed them to produce without large quantities of input.
At the end of the last century, with the introduction of fertilizers, the
development of plant breeding and modern techniques of livestock-rearing
and crop protection, yields have progressively grown to present the levels.
At the end of the 1970's, it became apparent that progress in
agriculture had brought with it several less desirable phenomena such as
the presence of residues of plant protection products in food, nitrates in
ground water, the degradation of certain soils, growing uniformity of the
countryside, and so on (F.A.O., 1994a).
Some of these negative effects, due to the increased agricultural
activity, may also affect the marine environment. Following is an outline
account of the various hazards emanating from agriculture with special
reference to the Maltese Islands.peer-reviewe
Manufacturing contamination prevention handbook
Manufacturing management discipline handbook concerning contamination prevention may present principles and guidelines which can be adopted for industrial and commercial manufacturer usage. Contamination prevention program is categorized into three basic aspects: initial prevention; control of amount of unpreventable contamination; and detection and elimination of remaining contamination
Bacterial contamination monitor
Economical, simple, and fast method uses apparatus which detects bacteria by photography. Apparatus contains camera, film assembly, calibrated light bulb, opaque plastic plate with built-in reflecting surface and transparent window section, opaque slide, plate with chemical packages, and cover containing roller attached to handle
Monitoring insulator contamination level under dry condition with a microwave reflectometer
āBuild-up of surface contamination on high voltage
insulators can lead to an increase in leakage current and partial
discharge, which may eventually develop into flashover.
Conventional contamination level monitoring systems based on
leakage current, partial discharge, infrared and ultraviolet
camera are only effective when the contamination layer has been
wetted by rain, fog or condensation; under these conditions
flashover might occur before there is time to implement remedial
measures such as cleaning. This paper describes studies exploring
the feasibility of applying microwave reflectometry techniques to
monitor insulator contamination levels. This novel method
measures the power generated by a 10.45 GHz source and
reflected at the insulator contamination layer. A theoretical
model establishes the relationship between equivalent salt deposit
density (ESDD) levels, dielectric properties and geometry of
contamination layers. Experimental results demonstrate that the
output from the reflectometer is able to clearly distinguish
between samples with different contamination levels under dry
conditions. This contamination monitoring method could
potentially provide advance warning of the future failure of wet
insulators in climates where insulators can experience dry
conditions for extended periods
Contamination control handbook
Contamination Control Handbook provides technical information on avoiding contamination of physical, chemical or biological systems or products. The book includes control methods for product design, gases and liquids, airborne and surface contamination, radiation, packaging handling, storage and personnel
Robust Estimation under Heavy Contamination using Enlarged Models
In data analysis, contamination caused by outliers is inevitable, and robust
statistical methods are strongly demanded. In this paper, our concern is to
develop a new approach for robust data analysis based on scoring rules. The
scoring rule is a discrepancy measure to assess the quality of probabilistic
forecasts. We propose a simple way of estimating not only the parameter in the
statistical model but also the contamination ratio of outliers. Estimating the
contamination ratio is important, since one can detect outliers out of the
training samples based on the estimated contamination ratio. For this purpose,
we use scoring rules with an extended statistical models, that is called the
enlarged models. Also, the regression problems are considered. We study a
complex heterogeneous contamination, in which the contamination ratio of
outliers in the dependent variable may depend on the independent variable. We
propose a simple method to obtain a robust regression estimator under
heterogeneous contamination. In addition, we show that our method provides also
an estimator of the expected contamination ratio that is available to detect
the outliers out of training samples. Numerical experiments demonstrate the
effectiveness of our methods compared to the conventional estimators.Comment: 32 pages, 3 figures, 3 table
Random contamination and select response styles affecting measures of fit and reliability in factor analysis
This research examines the effects of nonattending response pattern contamination and select response style patterns on measures of model fit (CFI) and internal reliability (Cronbach's Ī±). A simulation study examines the effects resulting from percentage of contamination, number of manifest items measured and sample size. Initial results indicate that sample size very mildly affects CFI but does not influence Ī±. Percent contamination decreases both CFI and Ī± in a nearly linear fashion over a limited range of contamination. Finally, whereas an increase in the number of manifest items increases resilience to random contamination for Ī±, the opposite was observed for CFI. An increase in the number of manifest items resulted in larger decreases in CFI. Implications are briefly discussed
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