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105-460: The refuge contains a diverse mixture of pine and hardwood forest, old fields, and wetland habitats, including vernal pools . The refuge is an "important feeding and breeding areas for migratory birds and other wildlife." The rare Blanding's turtle species is found in the refuge where it is monitored as scientists are working to help increase the population in the region. The refuge "is 70% forested and there are 476 acres designated as wetlands" with

210-519: A direct bandgap , and can be used in laser diodes and LEDs to convert electrical energy directly into light. After World War I , the United States built a stockpile of 20,000 tons of weaponized lewisite (ClCH=CHAsCl 2 ), an organoarsenic vesicant (blister agent) and lung irritant. The stockpile was neutralized with bleach and dumped into the Gulf of Mexico in the 1950s. During

315-711: A sink or a source of carbon, depending on the specific wetland. If they function as a carbon sink, they can help with climate change mitigation . However, wetlands can also be a significant source of methane emissions due to anaerobic decomposition of soaked detritus , and some are also emitters of nitrous oxide . Humans are disturbing and damaging wetlands in many ways, including oil and gas extraction , building infrastructure, overgrazing of livestock , overfishing , alteration of wetlands including dredging and draining, nutrient pollution , and water pollution . Wetlands are more threatened by environmental degradation than any other ecosystem on Earth, according to

420-568: A tetrahedral structure in which each atom is bound to each of the other three atoms by a single bond. This unstable allotrope, being molecular, is the most volatile, least dense, and most toxic. Solid yellow arsenic is produced by rapid cooling of arsenic vapor, As 4 . It is rapidly transformed into grey arsenic by light. The yellow form has a density of 1.97 g/cm . Black arsenic is similar in structure to black phosphorus . Black arsenic can also be formed by cooling vapor at around 100–220 °C and by crystallization of amorphous arsenic in

525-554: A wood preservative . In the 1930s, a process of treating wood with chromated copper arsenate (also known as CCA or Tanalith ) was invented, and for decades, this treatment was the most extensive industrial use of arsenic. An increased appreciation of the toxicity of arsenic led to a ban of CCA in consumer products in 2004, initiated by the European Union and United States. However, CCA remains in heavy use in other countries (such as on Malaysian rubber plantations). Arsenic

630-412: A "habitat for a large number of bird species as well as migratory birds and waterfowl" and otters , minks , turkeys , coyotes , beavers , foxes , and deer . On March 26, 2005, the refuge officially opened for wildlife-dependent recreation. A map of existing trails is available at the visitor center and at the refuge website. As of September 24, 2014, there are 15 miles (24 km) of trails open to

735-500: A German battleship could not shell the area. Each of the 50 bunkers, officially referred to as "igloos", has inside dimensions of 81 feet (25 m) by 26 feet (7.9 m) by 12 feet (3.7 m), and a curved roof. Sides and roofs were mounded with dirt for extra protection and camouflage from aerial view. Bunker #303 is sometimes open for tours. After World War II the site served as a troop training ground, ordnance testing, and laboratory disposal area for Natick Labs, otherwise known as

840-490: A distorted octahedral complex, with the three atoms in the same double-layer being slightly closer than the three atoms in the next. This relatively close packing leads to a high density of 5.73 g/cm . Grey arsenic is a semimetal , but becomes a semiconductor with a bandgap of 1.2–1.4 eV if amorphized . Grey arsenic is also the most stable form. Yellow arsenic is soft and waxy, and somewhat similar to tetraphosphorus ( P 4 ). Both have four atoms arranged in

945-402: A frequency and duration to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally included swamps, marshes, bogs, and similar areas.' For each of these definitions and others, regardless of the purpose, hydrology is emphasized (shallow waters, water-logged soils). The soil characteristics and

1050-517: A major source of arsenic contamination of groundwater in regions with high levels of naturally-occurring arsenic minerals. Synthetic arsenates include Scheele's Green (cupric hydrogen arsenate, acidic copper arsenate), calcium arsenate , and lead hydrogen arsenate . These three have been used as agricultural insecticides and poisons . The protonation steps between the arsenate and arsenic acid are similar to those between phosphate and phosphoric acid . Unlike phosphorous acid , arsenous acid

1155-1259: A polar climate, wetland temperatures can be as low as −50 °C (−58 °F). Peatlands in arctic and subarctic regions insulate the permafrost , thus delaying or preventing its thawing during summer, as well as inducing its formation. The amount of precipitation a wetland receives varies widely according to its area. Wetlands in Wales , Scotland , and western Ireland typically receive about 1,500 mm (59 in) per year. In some places in Southeast Asia , where heavy rains occur, they can receive up to 10,000 mm (390 in). In some drier regions, wetlands exist where as little as 180 mm (7.1 in) precipitation occurs each year. Temporal variation: Surface flow may occur in some segments, with subsurface flow in other segments. Wetlands vary widely due to local and regional differences in topography , hydrology , vegetation , and other factors, including human involvement. Other important factors include fertility, natural disturbance, competition, herbivory , burial and salinity. When peat accumulates, bogs and fens arise. The most important factor producing wetlands

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1260-540: A portion of the overall water cycle, which also includes atmospheric water (precipitation) and groundwater . Many wetlands are directly linked to groundwater and they can be a crucial regulator of both the quantity and quality of water found below the ground. Wetlands that have permeable substrates like limestone or occur in areas with highly variable and fluctuating water tables have especially important roles in groundwater replenishment or water recharge. Substrates that are porous allow water to filter down through

1365-404: A protective barrier to coastal shoreline. Mangroves stabilize the coastal zone from the interior and will migrate with the shoreline to remain adjacent to the boundary of the water. The main conservation benefit these systems have against storms and storm surges is the ability to reduce the speed and height of waves and floodwaters. Arsenic Arsenic is a chemical element with

1470-532: A role in human metabolism. However, arsenic poisoning occurs in multicellular life if quantities are larger than needed. Arsenic contamination of groundwater is a problem that affects millions of people across the world. The United States' Environmental Protection Agency states that all forms of arsenic are a serious risk to human health. The United States' Agency for Toxic Substances and Disease Registry ranked arsenic number 1 in its 2001 prioritized list of hazardous substances at Superfund sites. Arsenic

1575-422: A strong influence on wetland water chemistry, particularly in coastal wetlands and in arid and semiarid regions with large precipitation deficits. Natural salinity is regulated by interactions between ground and surface water, which may be influenced by human activity. Carbon is the major nutrient cycled within wetlands. Most nutrients, such as sulfur , phosphorus , carbon , and nitrogen are found within

1680-591: A subsidiary of Pfizer Inc., which produces roxarsone, voluntarily suspended sales of the drug in response to studies showing elevated levels of inorganic arsenic, a carcinogen, in treated chickens. A successor to Alpharma, Zoetis , continued to sell nitarsone until 2015, primarily for use in turkeys. During the 17th, 18th, and 19th centuries, a number of arsenic compounds were used as medicines, including arsphenamine (by Paul Ehrlich ) and arsenic trioxide (by Thomas Fowler ), for treating diseases such as cancer or psoriasis . Arsphenamine, as well as neosalvarsan ,

1785-410: A unique kind of wetland where lush plant growth and slow decay of dead plants (under anoxic conditions) results in organic peat accumulating; bogs, fens, and mires are different names for peatlands. Variations of names for wetland systems: Some wetlands have localized names unique to a region such as the prairie potholes of North America's northern plain, pocosins , Carolina bays and baygalls of

1890-415: A version of photosynthesis in the absence of oxygen with arsenites as electron donors , producing arsenates (just as ordinary photosynthesis uses water as electron donor, producing molecular oxygen). Researchers conjecture that, over the course of history, these photosynthesizing organisms produced the arsenates that allowed the arsenate-reducing bacteria to thrive. One strain , PHS-1, has been isolated and

1995-452: A wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic and aerobic processes, which, in turn, forces the biota, particularly rooted plants, to adapt to flooding". Sometimes a precise legal definition of a wetland is required. The definition used for regulation by the United States government is: 'The term "wetlands" means those areas that are inundated or saturated by surface or ground water at

2100-422: A wetland system includes its plants ( flora ) and animals ( fauna ) and microbes (bacteria, fungi). The most important factor is the wetland's duration of flooding. Other important factors include fertility and salinity of the water or soils. The chemistry of water flowing into wetlands depends on the source of water, the geological material that it flows through and the nutrients discharged from organic matter in

2205-403: A wetland) affects hydro-periods (temporal fluctuations in water levels) by controlling the water balance and water storage within a wetland. Landscape characteristics control wetland hydrology and water chemistry. The O 2 and CO 2 concentrations of water depend upon temperature , atmospheric pressure and mixing with the air (from winds or water flows). Water chemistry within wetlands

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2310-558: A whole. To replace these wetland ecosystem services , enormous amounts of money would need to be spent on water purification plants, dams, levees, and other hard infrastructure, and many of the services are impossible to replace. Floodplains and closed-depression wetlands can provide the functions of storage reservoirs and flood protection. The wetland system of floodplains is formed from major rivers downstream from their headwaters . "The floodplains of major rivers act as natural storage reservoirs, enabling excess water to spread out over

2415-594: A wide area, which reduces its depth and speed. Wetlands close to the headwaters of streams and rivers can slow down rainwater runoff and spring snowmelt so that it does not run straight off the land into water courses. This can help prevent sudden, damaging floods downstream." Notable river systems that produce wide floodplains include the Nile River , the Niger river inland delta, the Zambezi River flood plain,

2520-458: Is classified as a Group-A carcinogen . The three most common arsenic allotropes are grey, yellow, and black arsenic, with grey being the most common. Grey arsenic (α-As, space group R 3 m No. 166) adopts a double-layered structure consisting of many interlocked, ruffled, six-membered rings. Because of weak bonding between the layers, grey arsenic is brittle and has a relatively low Mohs hardness of 3.5. Nearest and next-nearest neighbors form

2625-440: Is determined by the pH , salinity , nutrients, conductivity , soil composition, hardness , and the sources of water. Water chemistry varies across landscapes and climatic regions. Wetlands are generally minerotrophic (waters contain dissolved materials from soils) with the exception of ombrotrophic bogs that are fed only by water from precipitation. Because bogs receive most of their water from precipitation and humidity from

2730-606: Is estimated that approximately 57 million people in the Bengal basin are drinking groundwater with arsenic concentrations elevated above the World Health Organization 's standard of 10 parts per billion (ppb). However, a study of cancer rates in Taiwan suggested that significant increases in cancer mortality appear only at levels above 150 ppb. The arsenic in the groundwater is of natural origin, and

2835-514: Is genuinely tribasic, with the formula As(OH) 3 . A broad variety of sulfur compounds of arsenic are known. Orpiment ( As 2 S 3 ) and realgar ( As 4 S 4 ) are somewhat abundant and were formerly used as painting pigments. In As 4 S 10 , arsenic has a formal oxidation state of +2 in As 4 S 4 which features As-As bonds so that the total covalency of As is still 3. Both orpiment and realgar, as well as As 4 S 3 , have selenium analogs;

2940-412: Is hydrology, or flooding . The duration of flooding or prolonged soil saturation by groundwater determines whether the resulting wetland has aquatic, marsh or swamp vegetation . Other important factors include soil fertility, natural disturbance, competition, herbivory , burial, and salinity. When peat from dead plants accumulates, bogs and fens develop. Wetland hydrology is associated with

3045-589: Is in alloying with lead. Lead components in car batteries are strengthened by the presence of a very small percentage of arsenic. Dezincification of brass (a copper-zinc alloy) is greatly reduced by the addition of arsenic. "Phosphorus Deoxidized Arsenical Copper" with an arsenic content of 0.3% has an increased corrosion stability in certain environments. Gallium arsenide is an important semiconductor material, used in integrated circuits . Circuits made from GaAs are much faster (but also much more expensive) than those made from silicon . Unlike silicon, GaAs has

3150-647: Is inhalation of atmospheric gases and dusts. During the Victorian era , arsenic was widely used in home decor, especially wallpapers. In Europe, an analysis based on 20,000 soil samples across all 28 countries show that 98% of sampled soils have concentrations less than 20 mg kg-1. In addition, the As hotspots are related to frequent fertilization and close distance to mining activities. Extensive arsenic contamination of groundwater has led to widespread arsenic poisoning in Bangladesh and neighboring countries. It

3255-427: Is little danger in eating fish because this arsenic compound is nearly non-toxic. Naturally occurring sources of human exposure include volcanic ash , weathering of minerals and ores, and mineralized groundwater. Arsenic is also found in food, water, soil, and air. Arsenic is absorbed by all plants, but is more concentrated in leafy vegetables, rice, apple and grape juice, and seafood. An additional route of exposure

Assabet River National Wildlife Refuge - Misplaced Pages Continue

3360-433: Is recovered primarily from copper refinement dust. On roasting arsenopyrite in air, arsenic sublimes as arsenic(III) oxide leaving iron oxides, while roasting without air results in the production of gray arsenic. Further purification from sulfur and other chalcogens is achieved by sublimation in vacuum, in a hydrogen atmosphere, or by distillation from molten lead-arsenic mixture. The word arsenic has its origin in

3465-561: Is related to the gammaproteobacterium Ectothiorhodospira shaposhnikovii . The mechanism is unknown, but an encoded Arr enzyme may function in reverse to its known homologues . In 2011, it was postulated that the Halomonadaceae strain GFAJ-1 could be grown in the absence of phosphorus if that element were substituted with arsenic, exploiting the fact that the arsenate and phosphate anions are similar structurally. The study

3570-467: Is released from the sediment into the groundwater, caused by the anoxic conditions of the subsurface. This groundwater was used after local and western NGOs and the Bangladeshi government undertook a massive shallow tube well drinking-water program in the late twentieth century. This program was designed to prevent drinking of bacteria-contaminated surface waters, but failed to test for arsenic in

3675-474: Is resistant to all-trans retinoic acid . A 2008 paper reports success in locating tumors using arsenic-74 (a positron emitter). This isotope produces clearer PET scan images than the previous radioactive agent, iodine -124, because the body tends to transport iodine to the thyroid gland producing signal noise. Nanoparticles of arsenic have shown ability to kill cancer cells with lesser cytotoxicity than other arsenic formulations. The main use of arsenic

3780-494: Is stable only below −50 °C, at which temperature it decomposes to the trichloride, releasing chlorine gas. ) Arsenic is used as the group 5 element in the III-V semiconductors gallium arsenide , indium arsenide , and aluminium arsenide . The valence electron count of GaAs is the same as a pair of Si atoms, but the band structure is completely different which results in distinct bulk properties. Other arsenic alloys include

3885-490: Is the 22nd most abundant element in seawater and ranks 41st in abundance in the universe. Minerals with the formula MAsS and MAs 2 (M = Fe , Ni , Co ) are the dominant commercial sources of arsenic, together with realgar (an arsenic sulfide mineral) and native (elemental) arsenic. An illustrative mineral is arsenopyrite ( Fe As S ), which is structurally related to iron pyrite . Many minor As-containing minerals are known. Arsenic also occurs in various organic forms in

3990-451: Is the only place in the world where both crocodiles and alligators coexist. The saltwater crocodile inhabits estuaries and mangroves. Snapping turtles also inhabit wetlands. Birds , particularly waterfowl and waders use wetlands extensively. Mammals of wetlands include numerous small and medium-sized species such as voles , bats , muskrats and platypus in addition to large herbivorous and apex predator species such as

4095-485: Is therefore called a monoisotopic element . As of 2024, at least 32 radioisotopes have also been synthesized, ranging in atomic mass from 64 to 95. The most stable of these is As with a half-life of 80.30 days. All other isotopes have half-lives of under one day, with the exception of As ( t 1/2 =65.30 hours), As ( t 1/2 =26.0 hours), As ( t 1/2 =17.77 days), As ( t 1/2 =26.26 hours), and As ( t 1/2 =38.83 hours). Isotopes that are lighter than

4200-496: Is typically pyramidal owing to the influence of the lone pair of electrons . One of the simplest arsenic compounds is the trihydride, the highly toxic, flammable, pyrophoric arsine (AsH 3 ). This compound is generally regarded as stable, since at room temperature it decomposes only slowly. At temperatures of 250–300 °C decomposition to arsenic and hydrogen is rapid. Several factors, such as humidity , presence of light and certain catalysts (namely aluminium) facilitate

4305-455: Is used to detect precise levels of intracellular arsenic and other arsenic bases involved in epigenetic modification of DNA. Studies investigating arsenic as an epigenetic factor can be used to develop precise biomarkers of exposure and susceptibility. The Chinese brake fern ( Pteris vittata ) hyperaccumulates arsenic from the soil into its leaves and has a proposed use in phytoremediation . Inorganic arsenic and its compounds, upon entering

Assabet River National Wildlife Refuge - Misplaced Pages Continue

4410-545: Is usually saturated with water". More precisely, wetlands are areas where "water covers the soil , or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season". A patch of land that develops pools of water after a rain storm would not necessarily be considered a "wetland", even though the land is wet. Wetlands have unique characteristics: they are generally distinguished from other water bodies or landforms based on their water level and on

4515-505: The Millennium Ecosystem Assessment from 2005. Methods exist for assessing wetland ecological health . These methods have contributed to wetland conservation by raising public awareness of the functions that wetlands can provide. Since 1971, work under an international treaty seeks to identify and protect " wetlands of international importance ." A simplified definition of wetland is "an area of land that

4620-688: The Pantanal in South America, and the Sundarbans in the Ganges - Brahmaputra delta. Wetlands contribute many ecosystem services that benefit people. These include for example water purification , stabilization of shorelines, storm protection and flood control . In addition, wetlands also process and condense carbon (in processes called carbon fixation and sequestration ), and other nutrients and water pollutants . Wetlands can act as

4725-712: The Renaissance era . During the Bronze Age , arsenic was melted with copper to make arsenical bronze . Jabir ibn Hayyan described the isolation of arsenic before 815 AD. Albertus Magnus (Albert the Great, 1193–1280) later isolated the element from a compound in 1250, by heating soap together with arsenic trisulfide . In 1649, Johann Schröder published two ways of preparing arsenic. Crystals of elemental (native) arsenic are found in nature, although rarely. Cadet's fuming liquid (impure cacodyl ), often claimed as

4830-539: The Syriac word ܙܪܢܝܟܐ zarnika , from Arabic al-zarnīḵ الزرنيخ 'the orpiment ', based on Persian zar ("gold") from the word زرنيخ zarnikh , meaning "yellow" (literally "gold-colored") and hence "(yellow) orpiment". It was adopted into Greek (using folk etymology ) as arsenikon ( ἀρσενικόν ) – a neuter form of the Greek adjective arsenikos ( ἀρσενικός ), meaning "male", "virile". Latin -speakers adopted

4935-584: The United States Army Soldier Systems Center . A 1980s assessment led to the area's categorization as an EPA Superfund clean-up site in 1990, as it was contaminated with arsenic , pesticides, and other chemicals, which were removed. Extensive Army clean-up efforts continued for years, ending with the site being turned over to the U.S. Fish & Wildlife Service in 2000. [REDACTED]  This article incorporates public domain material from websites or documents of

5040-663: The United States Fish and Wildlife Service . Wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water , either permanently, for years or decades, or only seasonally. Flooding results in oxygen -poor ( anoxic ) processes taking place, especially in the soils . Wetlands form a transitional zone between waterbodies and dry lands , and are different from other terrestrial or aquatic ecosystems due to their vegetation 's roots having adapted to oxygen-poor waterlogged soils . They are considered among

5145-631: The Vietnam War , the United States used Agent Blue , a mixture of sodium cacodylate and its acid form, as one of the rainbow herbicides to deprive North Vietnamese soldiers of foliage cover and rice. Some species of bacteria obtain their energy in the absence of oxygen by oxidizing various fuels while reducing arsenate to arsenite. Under oxidative environmental conditions some bacteria use arsenite as fuel, which they oxidize to arsenate. The enzymes involved are known as arsenate reductases (Arr). In 2008, bacteria were discovered that employ

5250-444: The atmosphere , their water usually has low mineral ionic composition. In contrast, wetlands fed by groundwater or tides have a higher concentration of dissolved nutrients and minerals. Fen peatlands receive water both from precipitation and ground water in varying amounts so their water chemistry ranges from acidic with low levels of dissolved minerals to alkaline with high accumulation of calcium and magnesium . Salinity has

5355-576: The beavers , coypu , swamp rabbit , Florida panther , jaguar , and moose . Wetlands attract many mammals due to abundant seeds, berries, and other vegetation as food for herbivores, as well as abundant populations of invertebrates, small reptiles and amphibians as prey for predators. Invertebrates of wetlands include aquatic insects such as dragonflies , aquatic bugs and beetles , midges, mosquitos , crustaceans such as crabs, crayfish, shrimps, microcrustaceans, mollusks like clams, mussels, snails and worms. Invertebrates comprise more than half of

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5460-490: The food chain , are progressively metabolized through a process of methylation . For example, the mold Scopulariopsis brevicaulis produces trimethylarsine if inorganic arsenic is present. The organic compound arsenobetaine is found in some marine foods such as fish and algae, and also in mushrooms in larger concentrations. The average person's intake is about 10–50 μg/day. Values about 1000 μg are not unusual following consumption of fish or mushrooms, but there

5565-457: The nonmetals . Though stable in dry air, arsenic forms a golden-bronze tarnish upon exposure to humidity which eventually becomes a black surface layer. When heated in air, arsenic oxidizes to arsenic trioxide ; the fumes from this reaction have an odor resembling garlic. This odor can be detected on striking arsenide minerals such as arsenopyrite with a hammer. It burns in oxygen to form arsenic trioxide and arsenic pentoxide , which have

5670-403: The symbol As and the atomic number 33. It is a metalloid and one of the pnictogens , and therefore shares many properties with its group 15 neighbors phosphorus and antimony . Arsenic is a notoriously toxic heavy metal . It occurs naturally in many minerals , usually in combination with sulfur and metals, but also as a pure elemental crystal . It has various allotropes , but only

5775-542: The 20th century. A 2006 study of the remains of the Australian racehorse Phar Lap determined that its 1932 death was caused by a massive overdose of arsenic. Sydney veterinarian Percy Sykes stated, "In those days, arsenic was quite a common tonic, usually given in the form of a solution ( Fowler's Solution ) ... It was so common that I'd reckon 90 per cent of the horses had arsenic in their system." The toxicity of arsenic to insects, bacteria, and fungi led to its use as

5880-521: The As ion as the formation of such an anion would be highly endothermic and even the group 1 arsenides have properties of intermetallic compounds. Like germanium , selenium , and bromine , which like arsenic succeed the 3d transition series , arsenic is much less stable in the +5 oxidation state than its vertical neighbors phosphorus and antimony , and hence arsenic pentoxide and arsenic acid are potent oxidizers . Compounds of arsenic resemble, in some respects, those of phosphorus , which occupies

5985-723: The Assabet River National Wildlife Refuge (FARNWR) is a non-profit organization formed in 2000, nearly a full year prior to the transfer of the annex to the U.S. Fish and Wildlife Service . Since that time, the Friends Group has provided the refuge invaluable assistance in preparing to open the refuge for wildlife-dependent recreational activities by removing physical safety hazards; conducting biological surveys of vernal pools, raptors , bats, invasive plant species ; and conducting numerous public outreach and education programs. The land on which

6090-595: The Assabet River in what is now the refuge in Maynard in his famous journal, and he wrote a poem entitled "Old Marlborough Road" about the road which ran from Concord to Marlborough, parts of which are in the ARNWR and now known as Winterberry Way and Powerline Trail. Origins of the refuge date back to the 1942 World War II -era seizure of land spanning Maynard, Sudbury, Hudson, and Stow by federal eminent domain as

6195-639: The Fort Devens-Sudbury Training Annex. Landowners were given about ten days to pack up and leave, and by their own accounts received around ten cents on the dollar of what the land was actually worth. One of the most interesting features of the refuge is the World War II-era ammunition bunkers. The site was chosen as it had convenient railroad shipping to the Boston Navy Yard , yet was far enough inland that

6300-552: The Greek term as arsenicum , which in French ultimately became arsenic , whence the English word "arsenic". Arsenic sulfides (orpiment, realgar ) and oxides have been known and used since ancient times. Zosimos ( c.  300 AD ) describes roasting sandarach (realgar) to obtain cloud of arsenic ( arsenic trioxide ), which he then reduces to gray arsenic. As the symptoms of arsenic poisoning are not very specific,

6405-486: The II-V semiconductor cadmium arsenide . A large variety of organoarsenic compounds are known. Several were developed as chemical warfare agents during World War I, including vesicants such as lewisite and vomiting agents such as adamsite . Cacodylic acid , which is of historic and practical interest, arises from the methylation of arsenic trioxide, a reaction that has no analogy in phosphorus chemistry. Cacodyl

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6510-639: The Okavango River inland delta, the Kafue River flood plain, the Lake Bangweulu flood plain (Africa), Mississippi River (US), Amazon River (South America), Yangtze River (China), Danube River (Central Europe) and Murray-Darling River (Australia). Groundwater replenishment can be achieved for example by marsh , swamp , and subterranean karst and cave hydrological systems. The surface water visibly seen in wetlands only represents

6615-522: The Southeastern US, mallines of Argentina, Mediterranean seasonal ponds of Europe and California, turloughs of Ireland, billabongs of Australia, among many others. Wetlands are found throughout the world in different climates. Temperatures vary greatly depending on the location of the wetland. Many of the world's wetlands are in the temperate zones , midway between the North or South Poles and

6720-502: The US, the best known classifications are the Cowardin classification system and the hydrogeomorphic (HGM) classification system. The Cowardin system includes five main types of wetlands: marine (ocean-associated), estuarine (mixed ocean- and river-associated), riverine (within river channels), lacustrine (lake-associated) and palustrine (inland nontidal habitats). Peatlands are

6825-430: The United States by 2013 in all agricultural activities except cotton farming. The biogeochemistry of arsenic is complex and includes various adsorption and desorption processes. The toxicity of arsenic is connected to its solubility and is affected by pH. Arsenite ( AsO 3− 3 ) is more soluble than arsenate ( AsO 3− 4 ) and is more toxic; however, at a lower pH, arsenate becomes more mobile and toxic. It

6930-610: The United States' commercial fish and shellfish stocks depend solely on estuaries to survive. Amphibians such as frogs and salamanders need both terrestrial and aquatic habitats in which to reproduce and feed. Because amphibians often inhabit depressional wetlands like prairie potholes and Carolina bays, the connectivity among these isolated wetlands is an important control of regional populations. While tadpoles feed on algae, adult frogs forage on insects. Frogs are sometimes used as an indicator of ecosystem health because their thin skin permits absorption of nutrients and toxins from

7035-438: The analogous As 2 Te 3 is known as the mineral kalgoorlieite , and the anion As 2 Te is known as a ligand in cobalt complexes. All trihalides of arsenic(III) are well known except the astatide, which is unknown. Arsenic pentafluoride (AsF 5 ) is the only important pentahalide, reflecting the lower stability of the +5 oxidation state; even so, it is a very strong fluorinating and oxidizing agent. (The pentachloride

7140-534: The dominant plants and the source of the water. For example, marshes are wetlands dominated by emergent herbaceous vegetation such as reeds , cattails and sedges . Swamps are dominated by woody vegetation such as trees and shrubs (although reed swamps in Europe are dominated by reeds, not trees). Mangrove forest are wetlands with mangroves , halophytic woody plants that have evolved to tolerate salty water . Examples of wetlands classified by

7245-572: The environment. In 2014, China was the top producer of white arsenic with almost 70% world share, followed by Morocco, Russia, and Belgium, according to the British Geological Survey and the United States Geological Survey . Most arsenic refinement operations in the US and Europe have closed over environmental concerns. Arsenic is found in the smelter dust from copper, gold, and lead smelters, and

7350-584: The equator. In these zones, summers are warm and winters are cold, but temperatures are not extreme. In subtropical zone wetlands, such as along the Gulf of Mexico , average temperatures might be 11 °C (52 °F). Wetlands in the tropics are subjected to much higher temperatures for a large portion of the year. Temperatures for wetlands on the Arabian Peninsula can exceed 50 °C (122 °F) and these habitats would therefore be subject to rapid evaporation. In northeastern Siberia , which has

7455-591: The fields). The accidental use of arsenic in the adulteration of foodstuffs led to the Bradford sweet poisoning in 1858, which resulted in 21 deaths. From the late-18th century wallpaper production began to use dyes made from arsenic, which was thought to increase the pigment's brightness. One account of the illness and 1821 death of Napoleon I implicates arsenic poisoning involving wallpaper. Two arsenic pigments have been widely used since their discovery – Paris Green in 1814 and Scheele's Green in 1775. After

7560-399: The first synthetic organometallic compound , was synthesized in 1760 by Louis Claude Cadet de Gassicourt through the reaction of potassium acetate with arsenic trioxide . In the Victorian era , women would eat "arsenic" (" white arsenic " or arsenic trioxide) mixed with vinegar and chalk to improve the complexion of their faces, making their skin paler (to show they did not work in

7665-504: The following areas: According to the Ramsar Convention: The economic worth of the ecosystem services provided to society by intact, naturally functioning wetlands is frequently much greater than the perceived benefits of converting them to 'more valuable' intensive land use – particularly as the profits from unsustainable use often go to relatively few individuals or corporations, rather than being shared by society as

7770-570: The grey form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition ). Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III–V compound semiconductor gallium arsenide . Arsenic and its compounds, especially the trioxide, are used in the production of pesticides , treated wood products, herbicides , and insecticides . These applications are declining with

7875-613: The groundwater. Many other countries and districts in Southeast Asia, such as Vietnam and Cambodia , have geological environments that produce groundwater with a high arsenic content. Arsenicosis was reported in Nakhon Si Thammarat , Thailand, in 1987, and the Chao Phraya River probably contains high levels of naturally occurring dissolved arsenic without being a public health problem because much of

7980-456: The increasing recognition of the toxicity of arsenic and its compounds. Arsenic has been known since ancient times to be poisonous to humans. However, a few species of bacteria are able to use arsenic compounds as respiratory metabolites . Trace quantities of arsenic have been proposed to be an essential dietary element in rats, hamsters, goats, and chickens. Research has not been conducted to determine whether small amounts of arsenic may play

8085-468: The interface between truly terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet highly dependent on both." In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. Under the Ramsar international wetland conservation treaty , wetlands are defined as follows: An ecological definition of

8190-462: The known animal species in wetlands, and are considered the primary food web link between plants and higher animals (such as fish and birds). Depending on a wetland's geographic and topographic location, the functions it performs can support multiple ecosystem services , values, or benefits. United Nations Millennium Ecosystem Assessment and Ramsar Convention described wetlands as a whole to be of biosphere significance and societal importance in

8295-438: The most biologically diverse of all ecosystems, serving as habitats to a wide range of aquatic and semi-aquatic plants and animals , with often improved water quality due to plant removal of excess nutrients such as nitrates and phosphorus . Wetlands exist on every continent , except Antarctica . The water in wetlands is either freshwater , brackish or saltwater . The main types of wetland are defined based on

8400-837: The plants and animals controlled by the wetland hydrology are often additional components of the definitions. Wetlands can be tidal (inundated by tides) or non-tidal. The water in wetlands is either freshwater , brackish , saline , or alkaline . There are four main kinds of wetlands – marsh , swamp , bog , and fen (bogs and fens being types of peatlands or mires ). Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types. Sub-types include mangrove forests , carrs , pocosins , floodplains , peatlands, vernal pools , sinks , and many others. The following three groups are used within Australia to classify wetland by type: Marine and coastal zone wetlands, inland wetlands and human-made wetlands. In

8505-408: The presence of mercury vapors. It is glassy and brittle. Black arsenic is also a poor electrical conductor. Arsenic sublimes upon heating at atmospheric pressure , converting directly to a gaseous form without an intervening liquid state at 887 K (614 °C). The triple point is at 3.63 MPa and 1,090 K (820 °C). Arsenic occurs in nature as one stable isotope , As, and

8610-552: The public for wildlife observation, half of which are open to biking. The Assabet River Rail Trail has a section with a north end at the South Acton (MBTA station) and a south end at the north entrance to ARNWR (from White Pond Road, Stow). The refuge is open for hunting and fishing, with hunting seasons set for deer, turkeys, grouse, woodcock, rabbits and squirrels. Dogs are not allowed, nor are other pets, horses, fires, overnight camping, ATVs, or snowmobiles. The Friends of

8715-938: The public uses bottled water . In Pakistan, more than 60 million people are exposed to arsenic polluted drinking water indicated by a 2017 report in Science . Podgorski's team investigated more than 1200 samples and more than 66% exceeded the WHO minimum contamination level. Since the 1980s, residents of the Ba Men region of Inner Mongolia, China have been chronically exposed to arsenic through drinking water from contaminated wells. A 2009 research study observed an elevated presence of skin lesions among residents with well water arsenic concentrations between 5 and 10 μg/L, suggesting that arsenic induced toxicity may occur at relatively low concentrations with chronic exposure. Overall, 20 of China's 34 provinces have high arsenic concentrations in

8820-444: The rate of decomposition. It oxidises readily in air to form arsenic trioxide and water, and analogous reactions take place with sulfur and selenium instead of oxygen . Arsenic forms colorless, odorless, crystalline oxides As 2 O 3 (" white arsenic ") and As 2 O 5 which are hygroscopic and readily soluble in water to form acidic solutions. Arsenic(V) acid is a weak acid and its salts, known as arsenates , are

8925-406: The same group (column) of the periodic table . The most common oxidation states for arsenic are: −3 in the arsenides , which are alloy-like intermetallic compounds, +3 in the arsenites , and +5 in the arsenates and most organoarsenic compounds. Arsenic also bonds readily to itself as seen in the square As 3− 4 ions in the mineral skutterudite . In the +3 oxidation state , arsenic

9030-443: The same structure as the more well-known phosphorus compounds, and in fluorine to give arsenic pentafluoride . Arsenic makes arsenic acid with concentrated nitric acid , arsenous acid with dilute nitric acid, and arsenic trioxide with concentrated sulfuric acid ; however, it does not react with water, alkalis, or non-oxidising acids. Arsenic reacts with metals to form arsenides , though these are not ionic compounds containing

9135-429: The soil and underlying rock into aquifers which are the source of much of the world's drinking water . Wetlands can also act as recharge areas when the surrounding water table is low and as a discharge zone when it is high. Mangroves , coral reefs , salt marsh can help with shoreline stabilization and storm protection. Tidal and inter-tidal wetland systems protect and stabilize coastal zones. Coral reefs provide

9240-537: The soil of wetlands. Anaerobic and aerobic respiration in the soil influences the nutrient cycling of carbon, hydrogen, oxygen, and nitrogen, and the solubility of phosphorus thus contributing to the chemical variations in its water. Wetlands with low pH and saline conductivity may reflect the presence of acid sulfates and wetlands with average salinity levels can be heavily influenced by calcium or magnesium. Biogeochemical processes in wetlands are determined by soils with low redox potential. The life forms of

9345-412: The soils and plants at higher elevations. Plants and animals may vary within a wetland seasonally or in response to flood regimes. There are four main groups of hydrophytes that are found in wetland systems throughout the world. Submerged wetland vegetation can grow in saline and fresh-water conditions. Some species have underwater flowers, while others have long stems to allow the flowers to reach

9450-530: The sources of water include tidal wetlands , where the water source is ocean tides ); estuaries , water source is mixed tidal and river waters; floodplains , water source is excess water from overflowed rivers or lakes; and bogs and vernal ponds , water source is rainfall or meltwater . The world's largest wetlands include the Amazon River basin , the West Siberian Plain ,

9555-406: The spatial and temporal dispersion, flow, and physio-chemical attributes of surface and ground waters. Sources of hydrological flows into wetlands are predominantly precipitation , surface water (saltwater or freshwater), and groundwater. Water flows out of wetlands by evapotranspiration , surface flows and tides , and subsurface water outflow. Hydrodynamics (the movement of water through and from

9660-476: The stable As tend to decay by β decay , and those that are heavier tend to decay by β decay , with some exceptions. At least 10 nuclear isomers have been described, ranging in atomic mass from 66 to 84. The most stable of arsenic's isomers is As with a half-life of 111 seconds. Arsenic has a similar electronegativity and ionization energies to its lighter pnictogen congener phosphorus and therefore readily forms covalent molecules with most of

9765-575: The substance was frequently used for murder until the advent in the 1830s of the Marsh test , a sensitive chemical test for its presence. (Another less sensitive but more general test is the Reinsch test .) Owing to its use by the ruling class to murder one another and its potency and discreetness, arsenic has been called the "poison of kings" and the "king of poisons". Arsenic became known as "the inheritance powder" due to its use in killing family members in

9870-719: The surface of the water. When trees and shrubs comprise much of the plant cover in saturated soils, those areas in most cases are called swamps . The upland boundary of swamps is determined partly by water levels. This can be affected by dams Some swamps can be dominated by a single species, such as silver maple swamps around the Great Lakes . Others, like those of the Amazon basin , have large numbers of different tree species. Other examples include cypress ( Taxodium ) and mangrove swamps. Many species of fish are highly dependent on wetland ecosystems. Seventy-five percent of

9975-496: The surface. Submerged species provide a food source for native fauna, habitat for invertebrates, and also possess filtration capabilities. Examples include seagrasses and eelgrass . Floating water plants or floating vegetation are usually small, like those in the Lemnoideae subfamily (duckweeds). Emergent vegetation like the cattails ( Typha spp.), sedges ( Carex spp.) and arrow arum ( Peltandra virginica ) rise above

10080-464: The surrounding environment resulting in increased extinction rates in unfavorable and polluted environmental conditions. Reptiles such as snakes , lizards , turtles , alligators and crocodiles are common in wetlands of some regions. In freshwater wetlands of the Southeastern US, alligators are common and a freshwater species of crocodile occurs in South Florida. The Florida Everglades

10185-456: The toxicity of arsenic became widely known, these chemicals were used less often as pigments and more often as insecticides. In the 1860s, an arsenic byproduct of dye production, London Purple, was widely used. This was a solid mixture of arsenic trioxide, aniline, lime, and ferrous oxide, insoluble in water and very toxic by inhalation or ingestion But it was later replaced with Paris Green , another arsenic-based dye. With better understanding of

10290-451: The toxicology mechanism, two other compounds were used starting in the 1890s. Arsenite of lime and arsenate of lead were used widely as insecticides until the discovery of DDT in 1942. In small doses, soluble arsenic compounds act as stimulants , and were once popular as medicine by people in the mid-18th to 19th centuries; this use was especially prevalent for sport animals such as race horses or work dogs and continued into

10395-440: The types of plants that live within them. Specifically, wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants . A more concise definition is a community composed of hydric soil and hydrophytes . Wetlands have also been described as ecotones , providing a transition between dry land and water bodies. Wetlands exist "...at

10500-605: The wildlife refuge sits was originally occupied by Native Americans and then became farmland for early colonists in the seventeenth and eighteenth centuries. During the Revolutionary War, ammunition wagons traveled along Old Marlborough Road (part of which is now a path in the refuge) from Concord to Marlborough to provide George Washington arms for his defense of Trenton . In 1851 transcendentalist Henry David Thoreau , who lived in Concord, wrote about his walk along

10605-489: Was also used in various agricultural insecticides and poisons. For example, lead hydrogen arsenate was a common insecticide on fruit trees , but contact with the compound sometimes resulted in brain damage among those working the sprayers. In the second half of the 20th century, monosodium methyl arsenate (MSMA) and disodium methyl arsenate (DSMA) – less toxic organic forms of arsenic – replaced lead arsenate in agriculture. These organic arsenicals were in turn phased out in

10710-451: Was found that addition of sulfur, phosphorus, and iron oxides to high-arsenite soils greatly reduces arsenic phytotoxicity. Arsenic is used as a feed additive in poultry and swine production , in particular it was used in the U.S. until 2015 to increase weight gain, improve feed efficiency , and prevent disease. An example is roxarsone , which had been used as a broiler starter by about 70% of U.S. broiler growers. In 2011, Alpharma,

10815-495: Was indicated for syphilis , but has been superseded by modern antibiotics . However, arsenicals such as melarsoprol are still used for the treatment of trypanosomiasis , since although these drugs have the disadvantage of severe toxicity, the disease is almost uniformly fatal if untreated. In 2000 the US Food and Drug Administration approved arsenic trioxide for the treatment of patients with acute promyelocytic leukemia that

10920-583: Was the first organometallic compound known (even though arsenic is not a true metal) and was named from the Greek κακωδία "stink" for its offensive, garlic-like odor; it is very toxic. Arsenic is the 53rd most abundant element in the Earth's crust , comprising about 1.5  parts per million  (0.00015%). Typical background concentrations of arsenic do not exceed 3 ng/m in the atmosphere; 100 mg/kg in soil; 400 μg/kg in vegetation; 10 μg/L in freshwater and 1.5 μg/L in seawater. Arsenic

11025-1020: Was widely criticised and subsequently refuted by independent researcher groups. Arsenic may be an essential trace mineral in birds, involved in the synthesis of methionine metabolites, with feeding recommendations being between 0.012 and 0.050 mg/kg. Some evidence indicates that arsenic is an essential trace mineral in mammals. However, the biological function is not known. Arsenic has been linked to epigenetic changes , heritable changes in gene expression that occur without changes in DNA sequence . These include DNA methylation, histone modification, and RNA interference. Toxic levels of arsenic cause significant DNA hypermethylation of tumor suppressor genes p16 and p53 , thus increasing risk of carcinogenesis . These epigenetic events have been studied in vitro using human kidney cells and in vivo using rat liver cells and peripheral blood leukocytes in humans. Inductively coupled plasma mass spectrometry (ICP-MS)

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