# Health Risk from Toxic Metals in Wild Rice Grown in Copper Mining-Impacted Sediments
## 3 Results and Discussion
### Toxic Metal Uptake and Accumulation in Wild Rice
For As, we observed a large uptake by the roots, with a bioaccumulation factor (BF) of 243.4 (Table 2, Figure 3A) for the wild rice samples from Sand Point, whereas the BF in shoots and seeds were 0.36 and 1.1, respectively. For the rice samples collected from Lake Plumbago, the BFs were lower in roots, shoots, and seeds (89.9, 1, and 1.1, respectively). BF value greater than one indicates bioaccumulation potential, which is seen in wild rice seed samples from both sites. Although the As levels were higher in the porewater in Lake Plumbago, the BFs in plant parts were lower, compared to those of the Sand Point samples. In contrast, the trace levels of Hg detected in the sediment and porewater showed no potential for plant uptake and bioaccumulation in wild rice in either location (Table 2, Figure 2B) because the BFs for all samples were below one. For Cd, while the BF for the Sand Point wild rice roots and shoots were 152.8 and 3.8, respectively, the value for seeds was below one. Similarly, for samples from Lake Plumbago, the BF for root samples was high (33.0) and the BF for shoots was below 1, while the BF for seeds was 1.9 (Table 2, Figure 2C). For Cr, seeds from both locations had BF values \(<\)1, while the roots showed high bioaccumulation (Table 2, Figure 2D). For two other toxic metals found in abundance, the BFs for Cu in Sand Point and Lake Plumbago root samples were 17.5 and 21.6, respectively (Table 2, Figure 3A). However, the BFs for shoot and seed samples from both locations were much lower. While for Sand Point wild rice samples, the BF for shoot samples was 1.9, the seed BF value was below one. For Lake Plumbago samples, the BF value for the shoot was below one, while for the seed samples it was 1.12 (Table 2, Figure 3A). For Zn, bioconcentration factors for wild rice plants from both locations were high (Table 2, Figure 3B). While for the Sand Point samples, the BFs for roots, shoots, and seeds were 29.9, 8.7, and 14, respectively, the BFs for wild rice harvested from Lake Plumbago were 9.1, 1.0, and 3.3 (Table 2, Figure 3B). As mentioned earlier, there are very few studies that examined the uptake, translocation, and bioconcentration of toxic metals in wild rice. According to a previous report by [PERSON] et al. [12] where wild rice plant tissue samples from four different locations in Northern Wisconsin were tested for the presence of toxic metals, As, Cd, Cr, Pb, and Se accumulated in the roots, whereas Cu and Zn were the highest in seeds. Interestingly, the study reported that Pb was low in roots, but was accumulated in the leaves and seeds [12]. Out of the four locations [PERSON] et al. [12] sampled, three had no known sources of contamination, whereas the fourth location was close to a Chlor-alkali plant that was the largest source of atmospheric Hg in Wisconsin. Despite sampling from sites not known to be contaminated, high levels of As, Pb, and Hg were reported in roots and seeds, which could indicate the presence of these metals in the sediments or the atmosphere. However, [PERSON] et al. [12] did not analyze sediment or water samples, so the bioconcentration factor could not be compared. However, the mean level of Cu they reported in wild rice seeds was 5.27 mg/kg, whereas a mean value of 9.0 mg/kg was reported by [PERSON] and [PERSON] [10] in store-bought wild rice. The average values of Cu in wild rice seeds from Sand Point and Lake Plumbago were 6.34 and 3.01 mg/kg, respectively, (\(p\) = 0.0016). Since Cu levels in the sediment (43.65 mg/kg) and roots (145 mg/kg) at the Sand Point location were high, these data indicate that translocation of Cu within the wild rice is low. The Lake Plumbago sediments had approximately half the level of Cu (23.47 mg/kg) compared to the Sand Point site (\(p\) = 0.0009); the Cu concentration in the roots was 57.83 mg/kg, and the corresponding level of the metal in the wild rice seeds was also approximately half that of the Sand Point site samples.