Cover Image
close this bookBasic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.)
close this folderIntroduction
View the documentUse of workshop
View the documentWorkshop participants
View the documentSupport staff
View the documentGlossary of commonly used environmental terms
View the documentList of references
close this folderEcological basics
View the documentEcosystem degradation
View the documentHabitat and niche
View the documentThe food chain
View the documentBiological magnification
View the documentNitrogen cycle
View the documentSociety and the carbon-oxygen cycle
View the documentHealth consequences of environmental degradation
View the documentPopulation and the environment
close this folderFreshwater and marine ecosystems
View the documentFreshwater ecosystems
View the documentEstuarine-mudflat ecosystems
View the documentSeagrass ecosystems
View the documentMangrove ecosystems
View the documentCoral reef ecosystems
View the documentHuman intrusions into the water cycle
View the documentDiversity of coastal and marine resources
View the documentPhilippine marine fisheries
View the documentMarine turtles
View the documentMarine food web
View the documentOcean pastures
View the documentThe menace of algal bloom
View the documentRed tide (Dynamics and public health aspects)
close this folderForest ecosystems
View the documentTropical forest -ecosystems
View the documentProtected areas: a tool for biological diversity conservation
View the documentEnvironmental effects of overexploitation for fuelwood in nearshore coastal resources
View the documentBiological diversity: and wildlife conservation
View the documentWildlife trade
close this folderGlobal warming and acid rain
View the documentClimate change and the greenhouse effect
View the documentHow deforestation contributes to the greenhouse effect
View the documentAcid rain
close this folderPollution
View the documentToxic and hazardous wastes
View the documentPollution and long-term effects on the human body
View the documentUrban pollution: The metro Manila environment
View the documentMining operations: environmental effects on soil, water, communities and atmosphere
View the documentPesticides: environmental and health effects
close this folderOthers
View the documentPhilippine commercial energy sources, 1990
View the documentCommon property resources in crisis
View the documentDegradation of the uplands
View the documentLowland degradation
View the documentEnvironmental issues in animal production
View the documentPlant genetic resources
View the documentNatural hazards

Toxic and hazardous wastes

Toxic and hazardous wastes


Human activities produce wastes. These wastes accumulate in amounts that may harm the environment and, at sufficiently high concentration, have undesirable effects on plants, animals and man. For example, mining processes contribute heavy metals which may be leached from exposed ores and. waste rocks such as iron, copper, mercury and lead. Factories which change raw materials to finished products produce large amounts of waste products. Industrial operations emit air pollutants like carbon monoxide, oxides of nitrogen, hydrocarbon and lead.

Damage to human health

Examples of toxic wastes affecting human health are numerous:

· Recently, just as the tong-term effects of mercury poisoning in Davao del Norte are being known, disturbing reports indicate that mercury poisoning is spreading to other parts of gold-rush Mindanao.

· In Metro Manila, a World Health Organization (WHO) study revealed that Metro Manilans are exposed to at least 10 times more lead in the air than WHO-prescribed standards. Lead mainly affects the central nervous system, causing fatigue, headache, tremors and convulsion.

· The Department of Agriculture warned residents of Monkayo, Davao del Norte, against eating the meat of animals suspected to have died after drinking from polluted bodies of water. Petrochemical analysis from the Bureau of Mines reported heavy traces of cyanide in water samples.

Important issues


So little is known about the health effects of hazardous wastes that setting exposure levels, in efforts to protect human health, often proves ineffective. Substances coming from wastes vary in their toxicities and produce different toxic effects. This is because they differ in the kinds of chemical reaction they undergo within the biochemical systems. For example, metallic mercury (Hg) is not poisonous. Ingestion of small amounts of mercury, as from a bit of silver amalgam a dentist uses to fill a cavity, is not considered a hazard. But, while metallic mercury is not toxic, its vapors are. Inhalation of enough mercury over a period of time affects the central nervous system, producing symptoms of insanity.

Hazardous Waste Management

Sound management of hazardous wastes is a goal not yet achieved in many countries, even developed ones. Many of the recommended/common ways of waste disposal have been proven to be ineffective and some even pose further hazards. For example, the sanitary landfill has been generally adopted as a substitute for open dumping and burning. Yet, it has been found that, in a sanitary landfill, there is a danger that explosive methane gas and toxic hydrogen sulfide gas, produced by anaerobic decomposition, can build up and explode.

Lack of Data

The lack of data on hazardous waste generation and its effects on health and environment continues to be a major stumbling block, thus hampering proper regulation.

Toxic and dangerous substances and materials that require priority consideration

Arsenic and compounds
Mercury and compounds
Cadmium and compounds
Thailium and compounds
Beryllium and compounds
Chromium(VI) compounds
Lead and compounds
Antimony and compounds
Phenolic compounds
Cyanide compounds
Organohalogenated compounds, excluding inert polymeric materials
Chlorinated solvents
Biocides and phytopharmaceutical substances
Tarry materials from refining and tar residues from distilling
Pharmaceutical compounds
Peroxides, chlorates, perchlorates and azides
Chemical laboratory materials
Selenium and compounds
Tellerium and compounds
Polycyclic aromatic hydrocarbons
Metal carbonyls
Soluble copper compounds
Acids and/or basic substances used in the surface treatment and finishing of metals
Organochlorines (e.g.,PCBs,DDT)