Horses have also been poisoned from crib biting tanalised rails and the loss of deer in recently constructed compounds has also been recorded in NZ. Dogs housed in kennels made from tanalised wood may develop contact dermatitis and arsenic poisoning. A weathering period of at least four weeks is considered necessary to reduce the risk to grazing animals.Įven seasoned timber may be dangerous and cases of poisoning are reported of possums housed in boxes made from tanalised timber.

Animals are exposed to a very real risk if they lick freshly tanalised wood. The arsenic oxide imparts a brown colour to treated wood. A green powder (copper chrome arsenic) may be left in the posts and battens that may contain up to 5% of arsenic. Timber can be preserved by soaking it for over 4 - 6 weeks in arsenical salts (eg copper chrome arsenic) or an arsenic oxide which are then fixed in the wood in a relatively insoluble form. It was once used in New Zealand as a rabbit and rat poison but its main use now is as a hide dressing, which contains 50% W/V of As2O3 (Trade name Peltex). Disturbances to the top layer of these soils, as in post hole digging, may allow puddles of water to accumulate in the underlying soil layers which contain toxic levels of arsenic.ĭuring the roasting of metallic ores as well as in the production of arsenic, arsenic trioxide is produced and may be carried as a dust to contaminate soil, herbage and water.Īrsenic trioxide is the most commonly used arsenical compound and being an amorphous or crystalline, white, tasteless powder its resemblance to flour and chalk has lead to many fatal poisonings. Soils in the thermal regions of New Zealand have particularly high arsenical concentrations, and mud from the Waiotapu valley has been shown to contain as much as 2% of arsenic. Natural sources of arsenic are arsenical pyrites (FeS2 FeAs2), the sulphates, realgar (As2S3) and orpiment (As2S3). Arsenical compounds are widely distributed in nature and can be found in soils and ores mainly as sulphides. Metallic arsenic exists in three oxidative states elementary, trivalent (arsenite) and pentavalent (arsenate). SourcesĪrsenic exists in two forms grey or metallic arsenic which is very stable and a metalloid form or yellow arsenic. Arsenic leaching into ground water from copper-chrome-arsenic treated fenceposts is currently causing concern. Nevertheless arsenic has been a constant source of poisoning to both humans and domestic animals. In recent years the incidence has declined due to the marked reduction in the use of arsenical compounds, the banning of arsenical sheep dips, and the replacement of arsenical orchard sprays, herbicides and other pesticides with more effective materials. Arsenic was once a very common cause of poisoning in farm animals and pets in NZ.

Arsenic poison antidote