ENVIRONMENTAL HAZARDS (PART TWO)

Chemical Hazards and their Health Effects

This is actually in continuation of the write-up on the Environmental Hazards around us.

Yes, we hear the word ‘chemicals’, we say chemicals, we even talk about chemicals, but we don’t take extra efforts in knowing how these chemicals affect our lives.

But first what are chemicals? Chemicals are substances that are artificially prepared or purified. Water, oxygen, gold are parts of chemicals in our environment.

Surprisingly, these chemicals are in our immediate environment and have their effects on us.

Now, what are chemical hazards in your environs? A chemical hazard is a type of occupational hazard which is caused by exposure to chemicals in the workplace, causing acute or long-term detrimental health effects.

But these chemical hazards are not limited to workplace alone; you can actually be exposed to chemical hazards in the comfort of your homes, in the buses, on the streets, everywhere, anywhere.

We can chemical hazards in form of liquids, vapors, fumes and flammable materials.

Tobacco smoke can be described as one of the environmental hazards that carry airborne chemical risk on health, in terms of death rates and ill-health associated with it. Diseases like lung cancer and other lung disease such as chronic bronchitis and emphysema, and disease of the heart, especially, and of blood vessels and other parts of the body are mostly caused by tobacco smoking. To a much lesser degree of risk, these adverse effects also apply to non-smokers exposed passively to side-stream tobacco smoke.

General airborne pollution is another chemical hazard in our environment. It arises from a variety of causes but can be subdivided into pollution from combustion or from other sources.

Combustion of coal and other solid fuels can produce smoke and sulphur dioxide and have them emitted into the environment.

Combustion of liquid petroleum products can generate carbon monoxide, oxides of nitrogen and other agents.

Industry and incineration can generate a wide range of products of combustion such as oxides of sulphur and nitrogen, polycyclic aromatic hydrocarbons, dioxins etc.

Combustion of fossil fuels generates varying amounts of particulate matter. It also adds to the environmental burden of carbon dioxide.

Nowadays some asthmatics people can be adversely affected by some levels of urban air pollution in most major cities around the world.

Health effects of this air pollution are asthma, bronchitis and similar lung diseases.

Products of combustion and other harmful airborne pollutants can also arise within the home. The nitrogen dioxide generated by gas fires or gas cookers can contribute to an increased respiratory morbidity of people living in the houses.

Certain modern building materials may liberate gases or vapors such as formaldehyde at low concentration, but which might eventually provoke mild respiratory and other symptoms in some occupants.

Special local environmental exposures can also arise in communities that are exposed to drifting pesticide sprays which may contain organophosphates. Organophosphates are a group of chemicals that have many domestic and industrial uses, though they are most commonly used as Insecticides and are also responsible for a number of poisonings to human health.

Some natural phenomena such as volcanic eruptions can also present serious risks to health to both environment and man. Fortunately they are rare but can be catastrophic.

Water can be an important source of chemical hazards. It can leach lead from pipes especially if the water is soft.

Some concern has been raised about possible increased cancer risks in association with chlorinated water but there is as yet no proof that a causal association between the two exists. Fluoride added to water reduces the risks of caries but can also have unwanted effects such as mottling of the teeth.

Nitrate in water usually arising from fertiliser leaching (natural or artificial) can increase the risk of methaemoglobinaemia ('blue babies') in bottle fed infants but this is extremely rare. Although pesticides can and do leach into water, there is no evidence that the current standards for water quality are inadequate in this respect, but most standards are based on evidence other than human epidemiology which in this context is extremely difficult to conduct.

Beyond the point of supply, further problems in drinking water quality may result. Thus for example water tanks containing lead may increase the burden of this metal in the water; while water softeners may increase its sodium content which can be harmful for bottle fed infants.

Deposition of solid hazardous waste can result in harmful substances leaching into water supplies, becoming airborne or being swallowed or otherwise absorbed directly by children playing at such sites. If the sites are well contained to prevent leaching into water supplies and segregated from human activity, then the risk to human health is usually immeasurably small.

However where the position of disposal sites and their contents are unknown and houses are proposed to be built on them or they are to be developed in other ways, extensive prior investigation may be needed in an attempt to estimate the health risks. 

To be continued......

NAHIMAT ADEKOGA