Table 4.

Heavy metal content and standard limits of rice grains (mg kg⁻¹).

Elements	Sample	AM	Maximum	Minimum	CV (%)	Chinese Standardized Value a	International Standardized Value b
As	52	0.09 ± 0.03	0.192	0.03	33.33	0.5	0.2
Cd	52	0.01 ± 0.01	0.099	0.001	100	0.2	0.4
Cu	52	1.57 ± 0.69	4.373	0.353	43.95	10	Null
Pb	52	0.002 ± 0.003	0.011	0.0003	150	0.2	0.2
Zn	52	11.56 ± 2.61	21.593	4.679	22.58	50	Null

^a From provisions on the limitation of heavy metals in rice grains in the National Food Safety Standard of the People’s Republic of China (GB 2762-2017) and the Agricultural Industry Standards of the People’s Republic of China (NY 861-2004); ^b From the Codex Alimentarius Commission (CAC) Standard Codex Stan 193-1995: adopted in 1995; revised in 1997, 2006, 2008, and 2009; amended in 2010, 2012, 2013, and 2014.