Introduction

With increasing evidence of cadmium's toxicity, both national and international agencies have sought to regulate its exposure. Because much is known about the toxic and health effects of cadmium; there is a large database from which to set standards for occupational, health, and environmental levels (Satoh et al. 2002).

Workplace Standards

OSHA has established workplace levels to protect the health of people occupationally exposed to cadmium.

The OSHA limits are

• Permissible Exposure Limit- TWA (PEL): 5 µg/m³ (fumes).

The National Institute of Occupational Safety and Health (NIOSH) has set an:

• Immediately Dangerous to Life and Health level (IDLH) which is 9 mg/m³ (NIOSH 2006; NTP 2004).

Health Standards

Many health agencies have set exposure standards designed to protect the general public from excess cadmium exposure from various sources.

FDA

• Maximum limit of cadmium in bottled water: 0.005 mg/L.

ATSDR

• Chronic durational oral minimal risk level (MRL) of 0.1 µg/kg/day of cadmium based on its renal effects.
• This MRL standard states how much cadmium can be taken in orally chronically without risk of adverse health effects (ATSDR 1999).

EPA

• Food - Reference dose is 1 x 10^-3 mg/kg/day (ATSDR 1999).
• Water - Reference dose for human exposure is 5 x 10^-4 mg/kg/day.
• Reference dose (Rfd) is an estimate of a daily exposure to the general population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious effects during a lifetime (IRIS 2006).

World Health Organization (WHO)

• Tolerable weekly intake for cadmium at 7�g/kg/body weight/week

Carcinogenicity

Positions on carcinogenicity of cadmium by U.S. and international health organizations.

• EPA classifies cadmium as a probable human carcinogen (Group B1).
• International Agency for Research on Cancer (IARC) classifies cadmium as a known human carcinogen.
• American Conference of Industrial Hygienists (ACGIH) classifies cadmium as a suspected human carcinogen.
• National Toxicology Program (NTP) classifies cadmium as known to be a human carcinogen (NTP 2004).

Environmental Standards

EPA

• Drinking water - maximum contaminant level for cadmium in drinking water is 0.005 mg/L. (ATSDR, 1999)
• Air - Cadmium is on the EPA National Emission Standards for Hazardous Air Pollutants (NESHAP) list of 189 hazardous air pollutants. Cadmium is listed as one of 33 hazardous air pollutants that present the greatest threat to public health in urban areas (ATSDR 1999).
• Soil – EPA biosolids rule states that the ceiling for the amount of cadmium that can be applied to land is 85 mg/kg fill material (NTP 2004).

Progress Check