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Arsenic and the food we eat

Arsenic is a naturally occurring element widespread in our environment. Consequently, most foods contain trace levels of arsenic. Occasional consumption and exposure to low levels of organic arsenic is not a health concern.

Where and why arsenic is present in our environment

Arsenic is a common element, widespread in nature in both living systems and geologically. It occurs in our food in both organic and inorganic forms. Arsenic combined with carbon and hydrogen is called organic arsenic. Inorganic arsenic is formed from the combination of arsenic with oxygen, chlorine or sulphur.

Arsenic is naturally present in all soils. The arsenic content of plants is usually determined by the arsenic content of the soil, water, air, fertilisers and other chemicals.

Water often contains arsenic and extremely high levels may be found in groundwater from areas with geothermal activity and with arsenic rich rocks (Anke, 1986)¹.

Fish and seafood can accumulate considerable amounts of organic arsenic from their environment (WHO, 1981)².

Arsenic levels may be affected by:

• the past use of pesticides containing arsenic

• proximity to smelters or coal fired power plants

• erosion caused by intensive land use.

The health concerns arising from arsenic in our food

Occasional consumption and exposure to low levels of organic arsenic is not a health concern. Organic arsenic is commonly found in seaweed and other marine foods but has not been linked to any human illnesses.

Inorganic arsenic, formed from the combination of arsenic with oxygen, chlorine or sulphur, is more toxic and is known to add to the risk of people getting cancer if it is regularly consumed. However, it is not usually found at high levels in food.

How we monitor arsenic levels in the New Zealand diet

Our New Zealand Total Diet Survey (NZTDS) measures the total arsenic content in individual foods.

Previously the Maximum Allowable Daily Body Load (MADL) of total arsenic was 50 micrograms / kilograms of bodyweight / day. The World Health Organization set this MADL in 1967.

More recently, the Joint Food and Agriculture Organization / World Health Organization Expert Committee on Food Additives (JECFA) has set a Provisional Tolerable Weekly Intake (PTWI) of 15 micrograms / kilogram of bodyweight / week for inorganic arsenic. The PTWI may also be expressed as ug / kg bw / week.

The estimated weekly dietary exposures to total arsenic for the eight age-sex groups of the 2003/04 New Zealand Total Diet Survey (NZTDS) are presented in the table below.

Estimated weekly dietary exposure to total arsenic for the eight age-sex groups of the 2003/04 NZTDS

The total arsenic content in New Zealand foods is decreasing over time, with weekly dietary exposures to total arsenic figures from the 2003/04 NZTDS compared to figures from previous surveys. Please refer to the table below.

Estimated weekly dietary exposure (micrograms/kg body weight/week) to total arsenic for a young male in the 2003/04 NZTDS compared to previous NZTDSs

a. Pickston et al, 1985

b. ESR/Ministry of Health, 1994

c. Vannoort et al, 1995

d. Vannoort et al, 2000

New Zealand Total Diet Survey – report on the 2003/04 results

Total and inorganic arsenic in the UK’s Total Diet Study, 1999 [UK Food Standards Agency]

¹ Anke M. (1986). Arsenic. In: Mertz W (ed). Trace Elements in Human Nutrition and Animal Nutrition (Fifth Edition), Volume 2. Orlando: Academic Press; 347-372.

² WHO. (1981). Arsenic. Environmental Health Criteria No. 18. Geneva: World Health Organization.