a little bit of info

From the AUSTRALIAN GOVERNMENT - Department of the Environment and Water Resourses (see link)

Arsenic and its compounds are ranked 10 out of 90 substances.

Health effects
What effect might arsenic and compounds have on my health?
Very high levels of arsenic can result in death. Consumption of lower levels of arsenic can cause digestive tract pain, nausea, vomiting and other stomach disorders, decreased production of red and white blood cells, damage to blood vessels, abnormal heart rhythms, a ‘pins and needles’ feeling in the hands and feet and liver and kidney damage.
Ingesting or inhaling low levels of inorganic arsenic for a long time can cause a darkening of the skin and the appearance of small ‘corns’ or ‘warts’ on the hands, feet and torso. Contact with inorganic arsenic may also cause redness and swelling to the skin.
Studies show that ingestion of inorganic arsenic can increase the risk of skin, lung, bladder, liver, kidney or prostate cancer. Inhalation of inorganic arsenic can increase the risk of lung cancer. Inorganic arsenic is a recognised human carcinogen, a substance capable of causing cancer.
Some studies have indicated that long-term exposure to low levels of arsenic in children may result in lower IQ scores. Children may be less efficient at converting inorganic arsenic to the less toxic organic arsenic. For this reason, children may be more susceptible to health effects than adults.
Some evidence exists that inhaled or ingested arsenic can affect pregnant women and their unborn babies. Large doses that cause illness to the pregnant females can also cause low birth weight, foetal malformations or foetal death. Arsenic can cross the placenta and may be found in foetal tissues. Arsenic has also been found at low levels in breast milk.