Fish and shellfish are an important part of our healthy diet as they are high in good fats, quality protein, and other essential nutrients while low in saturated fats. Yet many of these aquatic creatures worldwide are contaminated with persistent organochlorine compounds (POCs), which include PCBs, dioxins, and many organochlorine pesticides (e.g., DDT, HCB, lindane, chlordane). Insofar as these persistent chemicals are highly toxic and bioaccumulative, a basic understanding of their health impacts is crucial. The learning objectives of this first half of the lecture hence are to learn about: (1) the basic nutritional values of fish; (2) the toxicities of POCs; (3) the tolerance levels of POCs in fish, as so set forth by various health regulatory authorities worldwide; and (4) the fish consumption patterns occurring in some of the regions.