## 3 Results and Discussion
### Risk and Hazard Assessment in Seaweeds  
Seaweeds are regularly consumed and are increasingly being utilized as a main component of the diet, both in ROK and other parts of Asia. Several kinds of seaweeds are consumed in greater quantities than others. For example, both dried and seasoned types of layer (_Phyropia_ spp.) in red seaweed are highly popular as rice dishes, and up to 1 g dry weight might be consumed at every meal in ROK. Similarly, sea mustard (_U. pinnatifida_) and sea tangle (_S. japonica_) in brown seaweeds are used for making soups, seasoning materials, and salads; therefore, considerable quantities could be consumed. Other brown seaweeds, such as gulf-weed (_Sargassum_ spp. ), are occasionally used as side dishes mixed with a variety of vegetables. Of these, _S. fusiforme_ (_lijiki_), an edible seaweed, is used to supplement various dishes and salads. Figure 3: Biplot of principal component analysis (PCA) showing the relationship between seaweeds with marine animals (crustaceans, cephalopod, fish, and shellfish) and the levels of six arsenals. The directions of the straight dotted arrows indicate the relative loadings of As[V], As[III], MMA, DMA, AsB, and AsC on the basis of PC1 and PC2, and their lengths are proportional to their effects on seaweeds with marine animals. Groups: (A, \(\blacksquare\)) _Sargassum_ spp., (B, \(\bullet\)) _Pyropia_ sp., _Enteromorpha_ sp., _Undaria_ sp., and _Saccharina_ sp., (C, \(\square\)) crustaceans, (D, \(\odot\)) cephalopods, (E, \(\blacklozenge\)) fish, (F, \(\blacktriangle\)) shellfish. As shown in Table 4, the concentrations of Pb and Cd were at safe levels that are below the maximum threshold values recommended by France (Pb < 5 mg/kg dw and Cd < 0.5 mg/kg dw), China (Pb < 1 mg/kg dw) and ROK (Cd < 0.3 mg/kg dw for only layer). These results are considered to meet food safety standards. However, most _Sargassum_ seaweeds can be classified as high-risk foods, because the inorganic As concentrations in them exceed the regulations and limits of several countries, including France, Spain, Australia-New Zealand, and China (3.0, 2.0, 1.0 and 0.3 mg/kg dw, respectively). Although only a few species, such as _S. fusiforme_ and _S. thumbergii_, of _Sargassum_ spp. are used as edible seaweeds, the levels of inorganic As in both _S. fusiforme_ and _S. thumbergii_ were 9.853 and 13.166 mg/kg fw, respectively, and thus their consumption in large amounts may be unsafe. Many countries have actively regulated the intake and import of _Sargassum_ seaweeds, particularly _S. fusiforme_. The Canadian Food Inspection Agency warned the public to abstain from eating _S. fusiforme_. In 2004, the European Commission and the UK Food Standards Agency issued a risk alert for _S. fusiforme_. Food Standards Australia-New Zealand and the Hong Kong Centre for Food Safety publicly warned against _S. fusiforme_ and discontinued its import and sales. In Japan, _S. fusiforme_ was publicized as a health food rich in all kinds of vitamins and minerals, but the governmental guidelines state that intake of _S. fusiforme_ should be restricted to less than 4.7 g daily, and even lower for pregnant women, children, and those in poor health. Contrary to popular concerns, the _Sargassum_ group of seaweed is rarely consumed. Among them, _S. thumbergii_ is utilized as a material for stock feed or medicines (anti-helmithic components) rather than food [55], and while _S. fusiforme_ is a typical edible seaweed in this group, the mean daily intake is very low, \(\sim\)0.11 g, according to the statistical standards of ROK [56]. Moreover, most of As in the edible _Sargassum_ group, including in _S. fusiforme_, is removed during the production and cooking processes [57]. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) noted that the provisional tolerable weekly intake of 15 mg/kg body weight (bw; equivalent to 2.1 mg/kg bw/day) was established in 1989. The provisional tolerable weekly intake based on the concentration of inorganic As for _S.