California Rice

OEHHA Establishes Background Level of Inorganic Arsenic in Rice

California Rice
Rice grown near the Sacrmento Delta


California’s Office of Environmental Health Hazard Assessment (OEHHA) has gained approval from that state Office of Administrative Law approving amendments to Title 27, California Code of Regulations, Article 5. This action adopts new Section 25501.1 to provide guidance for businesses and the public by establishing default natural background levels for inorganic arsenic in white and brown rice.  These default background levels can assist businesses in determining the applicability of the warning requirements of Proposition 65.[1] 

The concentration levels established in Section 25501.1 account for the possible contribution of anthropogenic sources in deriving the naturally occurring safe harbor values for the section. The naturally occurring concentrations for of inorganic arsenic in rice are 80 parts per billion (ppb) for white rice and 170 ppb for brown rice.  This regulatory action will take effective on October 1, 2018.


The California Department of Food and Agriculture Soil Survey A study commissioned by the California Department of Food and Agriculture (CDFA) evaluated the toxic metal content of agricultural soil in California and the potential impact of fertilizers, which can contain trace elements such as arsenic33. Samples from Oxnard/Ventura, Santa Maria/San Luis Obispo Valley, Colusa/Glenn counties, Fresno, Coachella Valley, Imperial Valley, and Monterey/Salinas Valley were examined to compare arsenic concentrations in soils from uncultivated areas (i.e., baseline concentrations) to concentrations in cropland soils from the same region. To understand changes over time in arsenic levels in soils from uncultivated areas, the study compared total arsenic from archived soil samples collected in 1967 to samples from the same locations taken in 2001. The soil in these 50 sampling locations is considered representative of the different soil profiles found in California. While there were a few site-specific differences (the 2001 arsenic levels at five individual sites were above 1967 values), 1967 and 2001 levels of arsenic across these uncultivated areas overall did not significantly differ, as shown in Table 3 below. Thus, in the event that samples from uncultivated land in a particular region were unable to be obtained in 2001, levels from the 1967 samples from uncultivated land could confidently be compared to the 2001 cropland samples instead.

California is the second largest amount of rice cultivation of any state.  California currently exports 2.1 Billion pounds of rice per year.


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