Arsenic
Full Profile
(Group 1)
(Arsenic in Drinking Water, Group 1)
(Group 1)
General Information
Arsenic is a semi-metallic element. Although it is rare to find pure arsenic in nature, inorganic arsenic compounds are found in complex minerals containing copper, lead, iron, nickel, cobalt, and other metals.[2] Most arsenic compounds are white powders with no odour.[3] Of all commercially traded arsenic compounds, arsenic trioxide is the most important.[2] There are numerous other synonyms and product names for arsenic; see HSDB or IARC Monograph for more information.[4,5]
In both IARC Monograph Volumes 23 and 84, arsenic and its compounds were classified as Group 1, carcinogenic to humans. A recent IARC review of Class 1 carcinogens reaffirmed this classification.[32] The evaluation applies to the whole group, not necessarily to each individual compound.[4] Occupational epidemiology studies have established a strong association with inhalation exposure and the development of lung cancer, particularly in the smelting and mining industries.[3] Long-term exposure to arsenic through ingestion (i.e. medicinal, drinking water) can cause skin cancer.[2] Other cancer sites associated with arsenic exposure include the digestive tract, liver, bladder, kidney, prostate and lymphatic and hematopoietic systems.[2,32]
Discolouration and thickening of the skin on hands and feet are characteristic of chronic arsenic ingestion,[6] often preceding malignancy.[3] Neurological changes including peripheral neuropathies are also reported from low dose, chronic exposure.[3] Because of its effectiveness as a poison, data on acute exposure resulting in death is well established and includes respiratory, kidney and cardiovascular damage, and haematological changes.[3]
How did CAREX choose this agent for review?
Regulations and Guidelines
Occupational Exposure Limits (OEL)
| Canadian Jurisdictions | Substance | OEL |
|---|---|---|
| Canada Labour Code | Arsenic Arsine |
0.01 mg/m3 [bei] 0.005 ppm |
| MB, NL, PEI, NS | Arsenic Arsine |
0.01 mg/m3 [bei] 0.005 ppm |
| BC, ON | Arsenic Arsine |
0.01 mg/m3 0.005 ppm |
| SK | Arsenic | 0.01 mg/m3 0.03 [stel] |
| AB | Arsenic Arsine |
0.1 mg/m3 0.05 ppm |
| QC | Arsenic Arsine |
0.2 mg/m3 0.05 ppm |
| NB | Arsenic Arsine |
0.01 mg/m3 [bei] 0.05 ppm |
| YT | Arsenic Arsine |
0.5 mg/m3 0.05 ppm |
| NT and NU | Arsenic Arsine |
0.2 mg/m3 0.6 mg/m3 [stel] 0.05 ppm 0.15 ppm [stel] |
| Other Jurisdiction | Substance | OEL |
| ACGIH 2011 TLV | Arsenic Arsine |
0.01 mg/m3 [bei] 0.005 ppm |
Canadian Environmental Guidelines
| Jurisdiction | Limit | Year |
|---|---|---|
| Canadian Drinking Water Guidelines | 0.01 mg/L | 2010[7] |
| Ontario Outdoor Air Guidelines | 0.03 µg/m3 | 2006[9] |
| Canadian Soil Quality Guidelines for Environmental Health | 12 ppm | 1997[10] |
Arsenic was not included in other Canadian government environmental guidelines reviewed.[8]
Canadian Agencies/Organizations
| Agency | Designation/Position | Year (ref) |
|---|---|---|
| Health Canada | DSL – low priority substance (already risk managed) | 2006[11] |
| CEPA | Schedule 1 and 6, paragraphs 'b' and 'c' | 2011[12] |
Main Uses
Although the major use for arsenic has been for chromated copper arsenate (CCA) in the wood preservation industry, use patterns have changed in recent years.[13]
In December 2003, a voluntary agreement was made in the United States and Canada to stop using CCA in wood with residential applications including play structures, decks, fencing and boardwalks.[14] Prior to 2004, 90% of arsenic consumption in the US was for pressure treated wood; the figure reported for 2007 was 50%.[13] Marine timbers, plywood flooring and roofing, utility poles and glue-laminated beams can still be treated with CCA.
There are several other current uses of arsenic. One use occurs in the metallurgical industry, for hardening copper and lead-antimony alloys; applications include ammunitions, solders, battery posts, bearings and lead shot[13]. A second occurs in glassmaking, where arsenic is used as a bubble dispersant or colouring agent.[3] Finally, in the semi-conductor industry, high-purity arsenic is used in several semiconductor applications, such as; solar cells, light emitting diodes, lasers, and integrated circuits.[2]
Historically, arsenic has been included in agricultural chemicals, either directly of after conversion to arsenic acid, and was widely used as a pesticide and fertilizer. This is generally not allowed any longer,[3] though arsenicals may be used in emergency situations (e.g. pine beetle infestation).[15] Until the 1970s, arsenic was used in the treatment of leukemia, psoriasis, and asthma.[2] In the 1990s, there was renewed interest in the use of arsenic for treatment of a specific type of leukemia.[3]
Canadian Production and Trade
Historically, Canada produced refined arsenic trioxide in Ontario. The plant ceased smelting operations in 1961.[17] The USGS reports that arsenic trioxide is still produced by Canada (250 tonnes per year as of 2007).[13] The smelter in Trail, BC started producing gallium arsenide in 1981.[18]
Canadian arsenic was also obtained from the treatment of arsenious gold in mines operated in Ontario and the Northwest Territories.[16] In 1992, two mines were operational.[17]
Production and Trade
| Activity | Quantity | Year |
|---|---|---|
| Import: Mainly from the US | 41 t of 'arsenic' | 2010[11] |
Canada did not export arsenic in 2010.[11]
Occupational Exposures
Inhalation and dermal contact are the most important routes of occupational exposure.[2] The main occupations exposed include workers involved in mining, copper or lead smelting and the wood preservation industry.[2,3]
Environmental Exposures
Consumption of arsenic in food is generally considered the primary route of exposure for the general population not living near a point source, although drinking water can also be a significant source in areas where arsenic is found in bedrock.[21] Areas in Canada with arsenic-rich geologic deposits include the Yukon, Northern B.C., Nunavut Islands, the east coast, and few hot spots in Southern Ontario.[22]
Quantifying the relative contribution of food and drinking water is difficult because arsenic uptake varies based on the form (i.e. organic or inorganic) and valence state of arsenic.[23] Based on limited available research,[24,25] intake of inorganic arsenic, considered to be more toxic, is estimated to be 25% of total arsenic intake. In Canada, sources of arsenic in food include shellfish, meat, poultry, grain and dairy products.[26] In Ontario, 84% of the daily intake or arsenic was estimated to come from food, 15% from water, and <1% from soils/dusts and a negligible amount from skin contact.[26] This trend is expected to be relatively similar across Canada.
Arsenic in pigments and paints may be ingested through contamination of hands, fingernails, food, cups, or cigarettes.[2]
The average ambient air concentration in 11 Canadian cities and one rural site in 1990 was 0.001 µg/m3 (0.0005 – 0.017 µg/m3).[23] Although weathering and erosion of arsenic-containing rocks and soils contributes to natural levels of arsenic in the environment, anthropogenic sources are the most significant contributors. Examples include base-metal mining and gold production;[19] waste and coal burning[27]; leaching from arsenic treated sawdust and wood or smoke from treated wood;[2] and the applying of arsenic-based pesticides.[9]
Monosodium Methanearsonate (MSMA), an arsenic-containing pesticide, was used in BC forests from 1995-2004 in an attempt to slow the pine beetle infestation.[13] When arsenic accumulation in woodpeckers and other insect-feeding species became evident, MSMA was removed from BC markets.[28]
Some Canadian sites with high arsenic levels from mining/smelting residues include Moira Lake, Ont., Yellowknife, NWT, Bathurst, NB, and Rabbit Lake, Saskatchewan.[9] Samples taken recently near Sydney, Nova Scotia found 20% of background soil samples and 95% of tar pond soil samples were above Canadian health-based soil guidelines for arsenic.[29]
Searches of environmental and consumer product databases yielded the following results on current potential for exposure to arsenic in Canada:
NPRI and US Household Products Database
| NPRI 2009[26] | ||
|---|---|---|
| Search term: 'arsenic' | ||
| Category | Quantity | Industry |
| Released into Environment | 77.7t | Mining, smelters, waste control, pulp and paper, oil refineries, power generation, and wood production (221 companies) |
| Disposed of | 17,098t | |
| Sent to off-site recycling | 397.1t | |
| US Household Products 2010[31] | ||
|---|---|---|
| Search Term | Quantity | Product Type |
| 'arsenic and its compounds' | 1 | colourant |
Sources
- Wikimedia Commons Photo: Native arsenic
- NTP 12th report on carcinogens for Arsenic Compounds, Inorganic (2011) (PDF)
- ATSDR Toxicological Profile for Arsenic (2005) (PDF)
- IARC monograph volume 23, Suppl. 7, (1987) (PDF)
- Hazardous Substances Database (Search term: 'arsenic')
- ASTDR ToxFAQs Sheet (2007) (PDF)
- Guidelines for Canadian Drinking Water (2010) (PDF)
- Exposure Guidelines for Residential Indoor Air Quality (1987) (PDF)
- Wang, S, Mulligan C. Occurrence of arsenic contamination in Canada: Sources, behaviour and distribution. Sci. Tot. Environ. Volume 366, Issues 2-3, 2006, Pages 701-721
- Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health: Arsenic (Inorganic), Canadian Council of Ministers of the Environment (1997).
- Health Canada's Prioritization of the Domestic Substances List
- CEPA List of Toxic Substances
- US Geological Survey 2007 Arsenic Yearbook (PDF)
- Pest Management Regulatory Agency, re-evaluation Notice (PDF)
- Environment Canada: A Case against Arsenic Based Pesticides (2008)
- Summary of the Results of Environment Canada's Assessment 2000 Program for the Canadian Wood Preservation Industry. Prepared for Environment Canada. (PDF)
- Canadian Minerals Yearbook, 1960 (PDF)
- Canadian Minerals Yearbook, 1986 (PDF)
- Priority Substances List Assessment report (CEPA) for Arsenic and its Compounds (1993) (PDF)
- TradeMap (Canadian international trade data, free subscription required)
- World Health Organization: Arsenic in Drinking Water: Background document for the development of WHO Guidelines for Drinking-water Quality (2003) (PDF)
- Grosz, A.E., (2004), 'A preliminary geochemical map for arsenic in surficial materials of Canada and the United States' Applied Geochemistry, Vol. 19, pp. 257-260
- Health Canada, Environmental and Workplace Health: Arsenic
- Hazell, T. (1985) Minerals in foods: dietary sources, chemical forms, interactions, bioavailability. World Rev. Nutr. Diet., 46: 1.
- EPA (1988) Special report on ingested inorganic arsenic. Skin cancer; nutritional essentiality. Report No. EPA-625/3-87/013, Risk Assessment Forum, U.S. Environmental Protection Agency, Washington, DC.
- Arsenic in the Environment Fact Sheet, Government of Ontario, 2001 (PDF)
- Health Canada – It's Your Health: "Arsenic in Drinking Water" (PDF)
- Environment Canada: Wildlife and Landscape Science News, Summer 2008
- Lambert TW, Lane S (2004). 'Lead, arsenic, and polycyclic aromatic hydrocarbons in soil and house dust in the communities surrounding the Sydney, Nova Scotia, tar ponds,' Environmental Health Perspectives. Vol. 112, No. 1, pp. 35-41.
- The National Pollutant Release Inventory
- Household Products Database (US)
- IARC Monograph Volume 100: A review of human carcinogens—Part C: metals, arsenic, dusts, and fibres (2011)
Other Resources
- EU Research on Environmental Health; The ASHRAM Project; Arsenic health risk and molecular epidemiology
- EU legislation; Wood preserved with Arsenic
- EPA Arsenic in Drinking Water Webpage
- Studies of arsenic (and other contaminants) in Canadian Arctic communities, conducted under the Northern Contaminants Program (NCP)
- Decke P, Cohen B, Butala J, Gordon T (2002): 'Exposure to Wood Dust and Heavy Metals in Workers Using CCA Pressure-Treated Wood'American Industrial Hygiene Association Journal, Vol. 63, No. 2, pp. 166171
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