Heavy metals is a general term covering potentially toxic metals such as arsenic, cadmium, chromium, copper, lead, nickel and zinc. Heavy metals may be discharged into the environment and be found as suspended particulate matter in the atmosphere, in stream and marine sediments, or dissolved in water. There are 35 metals of major concern with regard to occupational exposure. About 20 of these may constitute occupational health hazards if not properly handled and may lead to toxic effects in humans. Toxicity may be either acute or chronic.

Acute toxic effects from metals are usually the result of the inhalation of air or the ingestion of liquids containing the metals in very high concentrations. Dangerously high concentrations of metals in workroom air may occur after industrial accidents (such as explosions, sudden leakage of metal fumes from normally closed containers, sudden failure in ventilation systems). Inhalation of high concentrations of metals is irritating and may cause severe damage to the respiratory tract. Fatalities may occur either immediately after exposure or up to several weeks later. Ingestion of high concentrations of metals may take also place through their leakage from containers and pipes into beverages. For example, acute intoxication has often occurred from consumption of home-brewed alcoholic drinks distilled in lead radiators or copper pans. The symptoms following the ingestion of excessive amounts of metals are those of food poisoning, with nausea, vomiting, abdominal pains and, in certain cases, diarrhoea.

The effects of chronic occupational exposure to metals are the most frequent, and are mainly derived from industrial activity. The toxicity of some metals, such as lead, has been known to man for centuries, and may lead to lead paralysis and colic. The inhalation of mercury vapour in mining and in the felt hat industry frequently causes severe central nervous-system symptoms; and long-term exposure to cadmium in workroom air causes pulmonary emphysema and kidney damage with proteinurea.

Illiteracy is the inability to read and write. A person is defined as illiterate if he cannot, with understanding, both read and write a short and simple statement on his everyday life; and as functionally illiterate if he cannot engage in all those activities in which literacy is required for the effective functioning of his group and community, and also for enabling him to continue to use reading, writing and calculation for his own and the community's development. Lack of such abilities prevents individuals from going about their daily activities in modern society, seeking suitable employment, or moving about normally with comprehension of the usual printed expressions and messages they encounter. Its consequences include inability to take up basic social services, fill in even simple forms, and understand traffic instructions or other danger signs.

Instability in the shipping industry in terms of cargo values and tons shipped cannot be separated from the major economic variables of production of manufactured goods and primary commodities. Shipping and shipbuilding industries also have a mutual dependence. Increased trade causes demand for tonnage; decreased trade means unutilized capacity. On the other hand, under-tonnaging and overtonnaging in relation to demand seems to be an industry characteristic, causing instability in freight rates. Tensions and uncooperative attitudes arise from competition between traditional maritime countries and organizations of major shipowners, and countries, many of them developing, and their shipowners and shippers seeking either to enter the industry or obtain fairer rates. Protectionism and politics play their parts in obstructing development of a better organization of international shipping. Within the shipping industry problems are generated by the instabilities in the commodities trades affecting cargoes. There are specific problems for tanker shipments of liquids, and for dry cargoes of which over 40% are bulk commodities.

Violation of civil rights is a daily state of affairs in many countries of the world.