256
Trace Elements in Abiotic and Biotic Environments
There is no evidence that exposure to naturally present levels of Ra has harmful
effects on human health. However, exposure to higher levels of Ra may result in
health effects, such as teeth fracture, anemia, and cataract. When the exposure lasts
for a long period of time, Ra may even cause cancer and the exposure can eventually
lead to death. These effects may take years to develop. They are usually caused by γ
radiation of Ra, which is able to travel fairly long distances through air.
Radium undergoes radioactive decay. During this process, α, β, and γ radiations are released. Alpha (α) particles can travel only a short distance and cannot
go through the skin. Beta (β) particles can penetrate through the skin, but they cannot go all the way through the human body, whereas γ radiation can go all the way
through the body.
Levels of occupational exposure to Ra are difficult to assess. Workers who are
occupationally exposed to Ra, through the mining and processing of U, are also
probably exposed simultaneously to U, Th, and Rn by inhalation and probably dermal exposure (ATSDR 1990a).
The International Agency for Research on Cancer (IARC 2012b, 2013) has classified 224 Ra, 226 Ra, 228 Ra, and their decay products in Group 1, human carcinogens.
226 Radium may occur in many different foods, and its activities have varied considerably. The mean 226 Ra contents of diets in 11 cities in the United States were
estimated to be from 0.52 to 0.73 pCi/kg of food consumed (0.019–0.027 Bq/kg).
Estimates of the mean concentrations of 226 Ra in milk and beef of the United States
are 0.23 pCi/L (0.009 Bq/L) and 0.22 pCi/kg (0.008 Bq/kg) fresh weight.
There is a potential for human exposure to Ra by the consumption of beef and
milk derived from cattle that graze on forage grown in soils containing Ra. No information is available on the occurrence of 228 Ra in food (ATSDR 1990a).
Average dietary exposure to 226 Ra (mBq/day) in different countries is estimated
as follows: Japan, 23; Poland, 42; Italy, 52; and the United States (New York), 52.
The greatest source of radionuclides in diet are cereals, potatoes, milk, and dairy
products (Pietrzak-Flis et al. 2001).
Trace Elements in Abiotic and Biotic Environments
There is no evidence that exposure to naturally present levels of Ra has harmful
effects on human health. However, exposure to higher levels of Ra may result in
health effects, such as teeth fracture, anemia, and cataract. When the exposure lasts
for a long period of time, Ra may even cause cancer and the exposure can eventually
lead to death. These effects may take years to develop. They are usually caused by γ
radiation of Ra, which is able to travel fairly long distances through air.
Radium undergoes radioactive decay. During this process, α, β, and γ radiations are released. Alpha (α) particles can travel only a short distance and cannot
go through the skin. Beta (β) particles can penetrate through the skin, but they cannot go all the way through the human body, whereas γ radiation can go all the way
through the body.
Levels of occupational exposure to Ra are difficult to assess. Workers who are
occupationally exposed to Ra, through the mining and processing of U, are also
probably exposed simultaneously to U, Th, and Rn by inhalation and probably dermal exposure (ATSDR 1990a).
The International Agency for Research on Cancer (IARC 2012b, 2013) has classified 224 Ra, 226 Ra, 228 Ra, and their decay products in Group 1, human carcinogens.
226 Radium may occur in many different foods, and its activities have varied considerably. The mean 226 Ra contents of diets in 11 cities in the United States were
estimated to be from 0.52 to 0.73 pCi/kg of food consumed (0.019–0.027 Bq/kg).
Estimates of the mean concentrations of 226 Ra in milk and beef of the United States
are 0.23 pCi/L (0.009 Bq/L) and 0.22 pCi/kg (0.008 Bq/kg) fresh weight.
There is a potential for human exposure to Ra by the consumption of beef and
milk derived from cattle that graze on forage grown in soils containing Ra. No information is available on the occurrence of 228 Ra in food (ATSDR 1990a).
Average dietary exposure to 226 Ra (mBq/day) in different countries is estimated
as follows: Japan, 23; Poland, 42; Italy, 52; and the United States (New York), 52.
The greatest source of radionuclides in diet are cereals, potatoes, milk, and dairy
products (Pietrzak-Flis et al. 2001).