Arsenic
General information
Arsenic causes many livestock deaths in Australia, even though there are few arsenic-based compounds registered for use here. Problems continue to occur because arsenic is a toxic metalloid and persists in the environment. Poisoning is usually due to carelessness in allowing animals access to materials contaminated with arsenic.
Overview
| Signs of poisoning | Clinical signs associated with poisoning depend on the form in which the arsenic is taken, the species of animal and the amount ingested. General signs of acute poisoning include purging, straining, abdominal pain and often diarrhoea containing blood and mucus. Weakness and a staggering gait are often noticed before convulsions and death. Unless a large amount of the chemical is consumed, signs usually take a day to become severe, and death may not occur for a week or more. Signs of chronic poisoning include emaciation, loss of appetite, swelling of joints, loss of hair and brick-red mucus membranes. Weakness increases as the animal approaches death. Diarrhoea may also be present. |
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| Diagnosis | Clinical signs associated with poisoning depend on the form in which the arsenic is taken, the species of animal and the amount ingested. General signs of acute poisoning include purging, straining, abdominal pain and often diarrhoea containing blood and mucus. Weakness and a staggering gait are often noticed before convulsions and death. Unless a large amount of the chemical is consumed, signs usually take a day to become severe, and death may not occur for a week or more. Signs of chronic poisoning include emaciation, loss of appetite, swelling of joints, loss of hair and brick-red mucus membranes. Weakness increases as the animal approaches death. Diarrhoea may also be present. |
| Treatment | If poisoning is suspected, consult your veterinary surgeon. Treatment involves removing any unabsorbed arsenic from the gut by oral purging with sodium thiosulphate. Supportive fluid therapy, antibiotics and anti-inflammatory drugs will also promote survival and recovery. |
| Sources of arsenic | The most significant sources of arsenic are old arsenical dip solutions used in the past for cattle tick and sheep lice control. Arsenic-based cattle dips were removed from the market in June 1983 and the use of arsenic-based products for sheep and cattle was banned in January 1987. However, poisonings still occur because the arsenic-based products were not always disposed of properly. Arsenic poisoning occurs when animals ingest the chemical, or absorb it through the skin. Ingestion is the more likely route of exposure as arsenic-based chemicals are no longer used for parasite control. In areas where old arsenical dips have been pumped out, the soil may contain potentially fatal concentrations of arsenic still in a form that can be absorbed by animals. Rain coupled with disturbance of the soil may produce a very attractive arsenic brew for any stock which have access. Burying arsenic will not stop soil contamination. Arsenic containers will eventually leak and the soluble arsenic can move through the soil and persist in locations which are accessible to livestock. Burial may also lead to pollution of underground water, streams or drainage areas. Storing concentrates in sheds or fenced-in areas which may be considered stock-proof is also potentially dangerous. |
| Disposing of arsenic | Discuss disposal options with your local council. |
| Sources of arsenic | The most significant sources of arsenic are old arsenical dip solutions used in the past for cattle tick and sheep lice control. Arsenic-based cattle dips were removed from the market in June 1983 and the use of arsenic-based products for sheep and cattle was banned in January 1987. However, poisonings still occur because the arsenic-based products were not always disposed of properly. Arsenic poisoning occurs when animals ingest the chemical, or absorb it through the skin. Ingestion is the more likely route of exposure as arsenic-based chemicals are no longer used for parasite control. In areas where old arsenical dips have been pumped out, the soil may contain potentially fatal concentrations of arsenic still in a form that can be absorbed by animals. Rain coupled with disturbance of the soil may produce a very attractive arsenic brew for any stock which have access. Burying arsenic will not stop soil contamination. Arsenic containers will eventually leak and the soluble arsenic can move through the soil and persist in locations which are accessible to livestock. Burial may also lead to pollution of underground water, streams or drainage areas. Storing concentrates in sheds or fenced-in areas which may be considered stock-proof is also potentially dangerous. |