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Arsenic in Groundwater Worldwide
Probability of occurrence of excessive arsenic concentrations
Various publications and web-sites were consulted to obtain information about the occurrence of arsenic in groundwater. An overview of regions with groundwater containing arsenic in excess of 50 µg/l is given in Appendix 1. Known aquifer types and sources of contamination are also included.
Geographical extent of areas contaminated with arsenic is shown on six continental maps (Figure 1 through 6). Probability of occurrence of excessive concentrations in these areas is indicated by three different colours:
- The areas indicated in red, have a relative high probability to contain arsenic in the groundwater. The locations of these areas are often well defined and many groundwater samples of these areas contain high concentrations of arsenic.
- The areas indicated in pink, have a relative low probability to contain arsenic contaminated groundwater. The precise location of the contaminated groundwater is not known and only few groundwater samples contain high concentrations of arsenic.
- Grey hatched areas are mentioned in the literature as contaminated areas, but no detailed information is available. For the remaining areas (indicated in yellow), no information about arsenic contamination has been found so far.
| Country | Region | Origin, natural or anthropogenic (concentration ranges ( µg l-1)) | Ref |
| Asia | |||
| Bengal basin | Holocene alluvial/deltaic sediments. Abundance of solid organic matter (<0.5-2500) | 9, 1 | |
| Cambodia | Mekong delta | Holocene alluvial/deltaic sediments. | 9 |
| China | Inner Mongolia (Tumet plain, Huhhot basin, Ba Men, Bayingao, Hexi) | Holocene alluvial and lacustrine sediments (<1-2400) | 9,1 |
| Xinjiang Provinces (Tianshan plain) | Holocene alluvial plain (40-750) | 9,1 | |
| Shanxi Province | Alluvial plain | 9,1 | |
| India | West Bengal (Bengal Basin) | Holocene alluvial/deltaic sediments. Abundance of solid organic matter (<10-3200) | 9,1 |
| Japan | Matsu&Turoko | Industrial | A |
| Kyushu | Geothermal field | 9 | |
| Mongolia | A | ||
| Myanmar | 9 | ||
| Nepal | Nawalparasi (Western region), Rautahat and Bara (Central), Bardia (Midwestern), Parsa, Rupandehi, Kapilbasthu and Banke | Recent sediments of the Terai region and groundwater of the active floodplain of the River Koshi | B |
| Pakistan | Indus River | 9 | |
| Philippines | Mindanao island | 12a | |
| Russia | Ural Mountain range | Mine drainage (400.000) | 9 |
| Kamchatka | Geothermal field | 9 | |
| Taiwan | Southwest and Northeast coastal zones | Sediments, including black shales (10-1820) | 9,1 |
| Thailand | Ron Phibun district, Nakhon Si Thammarat Province | Dredged Quaternary alluvium (some problems in limestone), tailing (1-5000) | 9 |
| Vietnam | Mekong delta, Red River delta | Holocene alluvial/deltaic sediments. (1-3050) | 9 |
| Europe | |||
| Austria | D | ||
| Belgium | Schelde estuary | Mining and industry (up to 30) | 9,1 |
| Denmark | D | ||
| England | Parts of SW England | Mining Pb, Ag | 9 |
| Estonia | Parts of NE Estonia | Industrial | 5 |
| France | Massif Central | Geothermal field | 9 |
| Germany | Bavaria | Upper Triassic Keuper Sandstone (<10-150) | 9 |
| Greece | Lavrion | Mining Pb, Ag | 9 |
| Thessaloniki | Geothermal field | 1 | |
| Hungary | Great Hungarian Plain | Alluvial Quaternary sediments (<2-176) | 9,1 |
| Iceland | Geothermal field | 9 | |
| Lithuania | D | ||
| Netherlands | Schelde estuary | Mining and industry | 1 |
| Romania | Great Hungarian Plain | Alluvial Quaternary sediments (<2-176) | 9 |
| Sweden | Kalix River estuary | Sediment pore water | 7 |
| North America | |||
| Canada | British Columbia | Mining (0.5-580) | 9 |
| Saskatchewan | Clay sediments, sediment pore water | 7 | |
| Ontario | Mining (35-100) | 9,1 | |
| Northwest Territories | Mining (64-530) | 9,1 | |
| Mexico | Lagunera region, Sonora province, other parts of northern Mexico | Volcanic sediments (Lagunera), calcareous formations (aquifer) (8-620) | 9,1 |
| Zimapan valley | Mining | 9 | |
| USA | San Joaquin valley, Tulare Basin, California | Holocene and older basin-fill sediments (<1-2600) | 9 |
| Southern Carson desert, Nevada | Holocene mixed aeolian, alluvial, lacustrine sediments, some thin volcanic ash bands (up to 2600) | 9 | |
| Basin and Range, Arizona | Alluvial basins, some evaporates (<1300) | 9 | |
| Coeur d'Alene district of Idaho | Valley-fill deposits (<1400) | 9 | |
| Lake Oahe, south Dakota | Lake sediments (<2000) | 9 | |
| Fairbanks mining district of Alaska | Schist, alluvium, mine tailings (<10000) | 9 | |
| Coeur d'Alene, Idaho | Pb-Zn-Ag mining | 9 | |
| Leviathan mine, California | Mining | 9 | |
| Kelly Creek Valley, Nevada | Mining | 9 | |
| Clark Fork River, Montana | Mining | 9 | |
| Lake Oahe, south Dakota | Mining | 9 | |
| Geyser Bight Umnak Island, Alaska | Geothermal field | 9 | |
| Honey Lake Basin, California | Geothermal field | 9 | |
| Coso Hot Springs, California | Geothermal field | 9 | |
| Imperial Valley, California | Geothermal field | 9 | |
| Long Valley, California | Geothermal field | 9 | |
| Steamboat Springs, Nevada | Geothermal field | 9 | |
| Yellowstone National Park | Geothermal field | 9 | |
| Lassen Volcanic National Park, California | Geothermal field | 9 | |
| South-eastern Michigan | E | ||
| South America | |||
| Argentina | Chaco-Pampean Plain | Quaternary deposits of loess (mainly silt) with intermixed rhyolitic or dacitic volcanic ash, often situated in closed basins (<1-5300). | 9,1 |
| Parts of Salta and Jujuy Provinces | Geothermal field | 9,1 | |
| Bolivia | Southern Altiplano (dept. Potosi) | Geothermal field | 1 |
| Chile | Antofagasta area | Quaternary volcanogenic sediments (100-1000) | 9,1 |
| El Tatio system in the Antofagasta region | Geothermal field | 9,1 | |
| Dominica | Geothermal field | 9 | |
| Jamaica | C | ||
| Peru | Mining | 3 | |
| Australia | |||
| New Zealand | Lake Ohakuri | Geothermal field | 9 |
| Wairakei | Geothermal field | 9 | |
| Broadlands | Geothermal field | 9 | |
| Orakei Korako | Geothermal field | 9 | |
| Atiamuri | Geothermal field | 9 | |
| Australia | Southeast Queensland | 8 | |
| New South Wales | Industry | 10, 2a, 6a | |
| Africa | |||
| Ghana | Ashanti Region, Central Ghana | Au mining | 9, 1 |
| Zimbabwe | Mining | 9 | |
| South Africa | Mining | 9 |
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