CHEMICALS IN THE ENVIRONMENT
There are many chemicals in the environment which can be detrimental to health. Some occur naturally and others are man made.
Although no single chemical may occur in illegal quantities, the cumulative affect of many different types of chemicals can increase a person's sensitivity and eventually lead to problems.
Chemicals may enter a property from many different sources, including:
1. Air Pollutants
Chemicals drift into your property in the air. Some remain suspended in air and may be inhaled. Others settle on your skin and may be absorbed through sweat glands. Other chemicals may settle on surfaces inside or outside a building, and over time accumulate (i.e. increase in concentration).
For example, exhaust fumes from cars, burning off garden waste by neighbours, factory smoke stacks, burning builders rubbish, etc.
2. Cleaning Chemicals
Many cleaning products contain dangerous chemicals. Even fumes from some concentrated chemicals may be dangerous in which case they should be mixed with water in a well ventilated place and inhaling should be avoided as this is done.
Some may leave residues in garden soil and hence should be disposed of carefully and properly. Some may leave a film of residue on cleaned surfaces, and should be washed off the surface with water after finishing cleaning. It may be advisable to schedule cleaning to be done when there are no other people around.
3. Chemical Breakdowns/Reactions
Many substances undergo chemical changes over time, some fast and others slow. Some of the resultant products may be very safe, but others may be poisonous.
For example, when treated pine logs, plastics, and some types of paint burn they will release toxic fumes. If left under normal conditions (in the absence of extreme heat), they may still release toxic chemicals but at a much slower and more manageable rate.
4. Leakages/Spills
Areas where beer, petrol, oil, kerosene, etc are spilt are difficult to grow plants in. Pesticide spills can result in very high concentrations of chemicals in an area (something which may never have been intended by the manufacturer).
5. Pesticides
Some pesticides will decompose quickly after application, leaving residues which are relatively harmless. Others are very slow to decompose and can continue to be toxic for decades or even longer. This ‘residual’ characteristic of a pesticide is measured in terms of ‘half life’.
Half life is the amount of time it takes, under ‘normal’ conditions, for 50% of the quantity of chemical applied to decompose. For example, DDT has a half life of 35 years, meaning if 1 litre is sprayed on an area, half a litre will still be active 35 years later.
Many chemicals which have been used to spray house foundations in the past (in developed countries) have half lives exceeding 100 years.
When applied, pesticides are often sprayed or dusted with the intention being for the chemical to be carried to the target area through the air. The problem is that movement of air is not really controllable or totally predictable. Some particles will inevitably find their way to places where they are not intended to go. If conditions are windy, and direction of air movement is changeable, the application of pesticides can become extremely unpredictable.
Uneven application of pesticides can result in higher than intended concentrations in some places. Only reliable, experienced operators following well defined safety procedures should apply residual pesticides in areas in which people live or work.
6. Solid Wastes
Some solid wastes, if not properly disposed of, can accumulate on a property. Builders rubbish is often not fully disposed of. Residues of concrete or plaster (dust or solid) can raise soil pH (making it more alkaline) and make it difficult to grow some types of plants in a garden.
Residues of acid (e.g. used to clean bricks) or metal will lower soil’s pH value making the soil more acidic. Sharp objects left behind may cause accidents (e.g. cuts) later on.
