Thyroid dysfunction Dental Fluorosis: David Kennedy and used with permission of victims of dental fluorosis. Exposure to excess fluoride can result in dental fluorosis, a condition in which the teeth enamel becomes irreversibly damaged.
Definition[ edit ] Kates defines environmental hazard as "the threat potential posed to man or nature by events originating in, or transmitted by, the natural or built environment". Hazards may be grouped according to their characteristics.
Areal extent of damage zone  Intensity of impact at a point  Duration of impact at a point  Rate of onset of the event  Predictability of the event  Natural hazards may be defined as "extreme events that originate in the biosphere, hydrosphere, lithosphere or atmosphere"  or "a potential threat to humans and their welfare"  which include earthquake, landslide, hurricane and tsunamis.
Technological and man made hazards include explosions, release of toxic materials, episodes of severe contaminationstructural collapses, and transportation, construction and manufacturing accidents etc.
A distinction can also be made between rapid onset natural hazards, technological hazards and social hazards which are described as being of sudden occurrence and relatively short duration, and the consequences of longer term environmental degradation such as desertification and drought, .
In this sense the environmental conditions we may consider hostile or hazardous can be seen as neutral in that it is our perception, human location and actions which identify resources and hazards within the range of natural events. He says "natural hazards, therefore, result from the conflict of geophysical processes with people and they lie at the interface what has been called the natural events system and the human interface system.
Firstly through location, because it is only when people and their possessions get in the way of natural processes that hazard exists. In this context we can see that there may be an acceptable variation of magnitude which can vary from the estimated normal or average range with upper and lower limits or thresholds.
In these extremes the natural occurrence may become an event that presents risk to the environment or people.
As long as the variation of the environmental element remains fairly close to this expected performance, insignificant damage occurs and the element will be perceived as beneficial. However when the variability exceeds some threshold beyond the normal band of tolerance, the same variable starts to impose a stress on society and become a hazard.
Classification[ edit ] Hazards can be classified as different types in several ways. One of these ways is by specifying the origin of the hazard. One key concept in identifying a hazard is the presence of stored energy that, when released, can cause damage.
Stored energy can occur in many forms: Another class of hazard does not involve release of stored energy, rather it involves the presence of hazardous situations. Examples include confined or limited egress spaces, oxygen-depleted atmospheres, awkward positions, repetitive motions, low-hanging or protruding objects, etc.
Hazards may also be classified as naturalanthropogenicor technological. They may also be classified as health or safety hazards and by the populations that may be affected, and the severity of the associated risk. In most cases a hazard may affect a range of targets, and have little or no effect on others.
Identification of hazards assumes that the potential targets are defined. Based on energy source[ edit ] Biological hazard Main article: The term and its associated symbol may be used as a warning, so that those potentially exposed to the substances will know to take precautions.
The biohazard symbol was developed in by Charles Baldwin, an environmental-health engineer working for the Dow Chemical Company on the containment products.
Biological hazards include viruses, parasites, bacteria, food, fungi, and foreign toxins. Many specific biological hazards have been identified. For example, the hazards of naturally-occurring bacteria such as Escherichia coli and Salmonellaare well known as disease-causing pathogens and a variety of measures have been taken to limit human exposure to these microorganisms through food safety, good personal hygiene and education.
However, the potential for new biological hazards exists through the discovery of new microorganisms and through the development of new genetically modified GM organisms. Use of new GM organisms is regulated by various governmental agencies. Bt corn and Roundup ready crops. Biological hazards can include medical waste or samples of a microorganismvirus or toxin from a biological source that can affect health.
Many biological hazards are associated with food, including certain virusesparasitesfungibacteriaand plant and seafood toxins.MATERIAL SAFETY DATA SHEET Product Name: Genfarm Metsulfuron WG Herbicide This revision issued: September, Page: 1 of 6 Issued by: .
The objective of a toxicological risk assessment is to evaluate the potential health risks associated with exposure to leachable impurities, contaminants, or other residues in a medical device or drug product.
Global methylmercury exposure from seafood consumption and risk of developmental neurotoxicity: a systematic review Mary C Sheehan a, Thomas A Burke b, Ana Navas-Acien c, Patrick N Breysse c, John McGready d & Mary A Fox b. a. Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, North Wolfe Street, Baltimore, MD , United States of . Module 2: Toxin Exposure Among Children Introduction: Toxic Chemicals. Chemicals surround us. Both natural and synthetic chemicals are used as pesticides, made into fibers for clothing, synthesized into medicines, and manipulated to build furniture, technological devices, and more. Exposure to airborne hazardous chemicals in the workplace can pose significant health risks to workers. Most exposure to these chemicals happens when workers inhale vapours, dusts, fumes or gases, but absorption through the skin may also be a significant source of exposure for some chemicals.
Tabulated dose-response assessments that the Office of Air Quality Planning and Standards (OAQPS) uses for risk assessments of hazardous air pollutants. Threshold of Toxicological Concern (TTC) aids assessment of human health risks from exposure to low levels of chemicals when toxicity data are limited.
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