Sentinel species are organisms, often animals, used to detect risks to humans by providing advance warning of a danger. The terms primarily apply in the context of environmental hazards rather than those from other sources. Some animals can act as sentinels because they may be more susceptible or have greater exposure to a particular hazard than humans in the same environment. [1] People have long observed animals for signs of impending hazards or evidence of environmental threats. Plants and other living organisms have also been used for these purposes.
Many observations of animals point to toxicity in food, water or air that would or could harm humans.
The classic example is the "canary in the coal mine". The idea of placing a warm-blooded animal in a mine to detect carbon monoxide was first proposed by John Scott Haldane in 1895, [2] and canaries were used as early as 1896. [3] [4] [5] [6] Countries such as Britain, the United States, and Canada used canaries as a sentinel species. [7] Well into the 20th century, coal miners brought canaries into coal mines as an early-warning signal for toxic gases, primarily carbon monoxide. [8] The birds, being more sensitive, would become sick before the miners, who would then have a chance to escape or put on protective respirators. In some cases, the canaries were kept in cages with dedicated oxygen tanks so the birds could survive after their illness provided a warning. [9] "Canary in the coal mine" is now used as an idiom for a person or thing that warns people of danger. [10] [11]
In Minamata Bay, Japan, cats developed "dancing cat fever" before humans were affected due to eating mercury-contaminated fish. [12]
Dogs were recognized as early as 1939 to be more susceptible to tonsil cancer if they were kept in crowded urban environments. [12] Studies similarly found higher disease rates in animals exposed to tobacco smoke. [12]
Yushō disease was discovered when poultry began dying at alarming rates due to polychlorinated biphenyl (PCB) poisoning, although not before approximately 14,000 people were affected.
Rose bushes are often planted at the ends of vine rows in vineyards. One hypothesized reason is that roses are highly susceptible to powdery mildew, which can also afflict grape vines. Finding mildew on the roses is therefore sometimes taken as an early warning sign to take preventive measures to protect the adjacent vines. However the effectiveness of this practice is debated, since roses and vines are affected by different species of mildew (although both species occur under similar weather conditions). [13]
Animal sentinels must have measurable responses to the hazard in question, whether that is due to the animal's death, disappearance, or some other determinable aspect. [1] : 34 Many of these species are ideally unendangered and easy to handle. It is important that the species' range overlap with the range being studied. [14] Often the ideal species is determined by the characteristics of the hazard.
For example, honey bees are susceptible to air pollution. [1] : 35 Similarly both bats and swallows have been used to monitor pesticide contamination due to their diet of insects that may have been affected by the chemicals. [1] : 35 By the same token, aquatic animals, or their direct predators, are used as sentinel species to monitor water pollution. [15]
Some species may show effects of a contaminant before humans due to their size, their reproductive rate, or their increased exposure to the contaminant. [14]
Canaries were iconically used in coal mines to detect the presence of carbon monoxide. The bird's rapid breathing rate, small size, and high metabolism, compared to the miners, led birds in dangerous mines to succumb before the miners, thereby giving the miners time to take action.
A number of animals have been used to measure varying kinds of air pollution. These include honey bees for air pollution, bivalve molluscs [16] for online water-quality survey and pigeons for atmospheric lead. [1] : 35 Bats and swallows have been used to monitor pesticide contamination due to their diet of insects that may have been affected by the chemicals. [1] : 35
Aquatic DDT pollution has been quantitatively measured in California fish. PCB has been measured through the analysis of fish livers. [1] : 82 Toxaphene concentrations were discovered far from the area of its use through analysis of trout in the Great Lakes. [1] : 85 The evidence of atmospheric transport of the substance influenced the subsequent prohibition of its widespread use. Alligators may have been used to warn of hazardous contamination in Centreville, Mississippi retention ponds. [17]
Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there. [18] [19] [20]
The Protivin brewery in the Czech Republic uses crayfish outfitted with sensors to detect any changes in their bodies or pulse activity in order to monitor the purity of the water used in their product. The creatures are kept in a fish tank that is fed with the same local natural source water used in their brewing. If three or more of the crayfish have changes to their pulses, employees know there is a change in the water and examine the parameters. [18]
The discovery of West Nile virus in the Western Hemisphere was heralded by an outbreak of disease in crows and other wild birds. Other emerging diseases have demonstrated linkages between animal health events and human risk, including monkeypox, SARS, and avian influenza. In outbreaks of bubonic plague, rats begin dying out before humans. [ citation needed ]
Dogs may provide early warning of lead poisoning hazards in a home, and certain cancers in dogs and cats have been linked to household exposures to pesticides, cigarette smoke, and other carcinogens. [ citation needed ]
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance or energy. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
Water pollution is the contamination of water bodies, with a negative impact on their uses. It is usually a result of human activities. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources. These are sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. Water pollution may affect either surface water or groundwater. This form of pollution can lead to many problems. One is the degradation of aquatic ecosystems. Another is spreading water-borne diseases when people use polluted water for drinking or irrigation. Water pollution also reduces the ecosystem services such as drinking water provided by the water resource.
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the incomplete combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires.
Afterdamp is the toxic mixture of gases left in a mine following an explosion caused by methane-rich firedamp, which itself can initiate a much larger explosion of coal dust. The term is etymologically and practically related to other terms for underground mine gases—such as firedamp, white damp, and black damp, with afterdamp being composed, rather, primarily by carbon dioxide, carbon monoxide and nitrogen, with highly toxic stinkdamp-constituent hydrogen sulfide possibly also present. However, the high content of carbon monoxide is the component that kills, preferentially combining with haemoglobin in the blood and thus depriving victims of oxygen. Globally, afterdamp has caused many of the casualties in disasters of pit coalfields, including British, such as the Senghenydd colliery disaster. Such disasters continue to afflict working mines, for instance in mainland China.
John Scott Haldane was a British physician physiologist and philosopher famous for intrepid self-experimentation which led to many important discoveries about the human body and the nature of gases. He also experimented on his son, the celebrated and polymathic biologist J. B. S. Haldane, even when he was quite young. Haldane locked himself in sealed chambers breathing potentially lethal cocktails of gases while recording their effect on his mind and body.
Mountaintop removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining at the summit or summit ridge of a mountain. Coal seams are extracted from a mountain by removing the land, or overburden, above the seams. This process is considered to be safer compared to underground mining because the coal seams are accessed from above instead of underground. In the United States, this method of coal mining is conducted in the Appalachian Mountains in the eastern United States. Explosives are used to remove up to 400 vertical feet of mountain to expose underlying coal seams. Excess rock and soil is dumped into nearby valleys, in what are called "holler fills" or "valley fills".
Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels.
Human impact on the environment refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the needs of society is causing severe effects including global warming, environmental degradation, mass extinction and biodiversity loss, ecological crisis, and ecological collapse. Some human activities that cause damage to the environment on a global scale include population growth, neoliberal economic policies and rapid economic growth, overconsumption, overexploitation, pollution, and deforestation. Some of the problems, including global warming and biodiversity loss, have been proposed as representing catastrophic risks to the survival of the human species.
A bioindicator is any species or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot.
Aquatic biomonitoring is the science of inferring the ecological condition of rivers, lakes, streams, and wetlands by examining the organisms that live there. While aquatic biomonitoring is the most common form of biomonitoring, any ecosystem can be studied in this manner.
Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals or improper disposal of waste. The most common chemicals involved are petroleum hydrocarbons, polynuclear aromatic hydrocarbons, solvents, pesticides, lead, and other heavy metals. Contamination is correlated with the degree of industrialization and intensity of chemical substance. The concern over soil contamination stems primarily from health risks, from direct contact with the contaminated soil, vapour from the contaminants, or from secondary contamination of water supplies within and underlying the soil. Mapping of contaminated soil sites and the resulting clean ups are time-consuming and expensive tasks, and require expertise in geology, hydrology, chemistry, computer modelling, and GIS in Environmental Contamination, as well as an appreciation of the history of industrial chemistry.
Environmental issues in Australia describes a number of environmental issues which affect the environment of Australia and are the primary concern of the environmental movement in Australia.
Environmentally, Colombia is a mega-diverse country from its natural land terrain to its biological wildlife. Its biodiversity is a result of its geographical location and elevation. It is the fourth largest South American country and only country in South America to have coasts on the Pacific and Caribbean Sea. Colombia's terrain can be divided into six main natural zones: The Caribbean, the Pacific, The Orinoco region, The Amazonia region, the Andean region, and the Insular region. 52.2% of the environment is predominately the Andes, Amazon, and Pacific Basins, followed by the Orinoco basin 13.9%, the Andes and the Caribbean. The Tropical Andes, Choco, and the Caribbean are considered biodiversity hotspots which puts these areas at high risk of concentration of colonizing activities. Colombia host over 1800 bird species and at least one new species are detected every year. Decades of civil war and political unrest have impeded biological and environmental research in Colombia. The political unrest in Colombia catalyzes the alteration of land patterns through the cultivation of coca and opium crops, the redirection of extractive activities, and land abandonment in some areas.
The domestic canary, often simply known as the canary, is a domesticated form of the wild canary, a small songbird in the finch family originating from the Macaronesian Islands.
Blackdamp is an asphyxiant, reducing the available oxygen content of air to a level incapable of sustaining human or animal life. It is not a single gas but a mixture of unbreathable gases left after oxygen is removed from the air and typically consists of nitrogen, carbon dioxide and water vapour. The term is etymologically and practically related to terms for other underground mine gases such as fire damp, white damp, stink damp, and afterdamp.
Environmental toxicology is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels.
The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal burning produces hundreds of millions of tons of solid waste products annually, including fly ash, bottom ash, and flue-gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals. Coal is the largest contributor to the human-made increase of carbon dioxide in Earth's atmosphere.
Environmental effects of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change.
Environmental health policy is governmental action intended to prevent exposure to environmental hazards or "eliminate the effects of exposure to environmental hazards".
A bioassay is an analytical method to determine the potency or effect of a substance by its effect on living animals or plants, or on living cells or tissues. A bioassay can be either quantal or quantitative, direct or indirect. If the measured response is binary, the assay is quantal; if not, it is quantitative.
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