Could you inform me about the other biocides?

Herbicides are used to destroy the weeds without doing any harm to crop. These are mostly used in agriculture.

The major herbicides used today include 2,4-D, atrazine, dicamba, clopyralid, glufosinate ammonium, glyphossate, imazapic, linuron, metoalachlor, triclopyr, picloram and paraquat

Nematicide is a pesticide used to kill the parasitic roundworms. A mixture of neem cake is reported to be an effective nematicide. Several compounds from carbamates, oxime carbamates, organophosphorus, organophosphate and phosphonothioate are used as nematicides.

Miticides or acaricides are the pesticides used to destroy and eradicate mites. Carbamate, organochlorine, permethrin and organophosphate miticides are the common ones.

Molluscicides are called snail baits and are pesticides against all sorts of snails that can damage the crops in agriculture or in garden. Iron III phosphate, aluminium sulphate, metaldehyde and acetyl cholinesterase inhibitors are the commonly used molluscicides and the last one is highly toxic to animals and human beings.

Rodenticides are poisons used to kill rodents such as rat and mouse. Rodenticides are tasteless, odourless, and lethal and have delayed poisonous effect. Rodents, normally, eat little, wait and if they do not become sick, they eat further.

The important rodenticides include:

• Anticoagulants, for example 4-hydroxycumarin
• Metal phosphides, for example zinc phosphide
• Arsenic
• Bromethalin
• Chloralose
• Crimidine
• 4-amine
• Phosacetim
• Fluoroacetamise
• Endrin
• 1, 3-Difluoro-2-propanol
• Pyrinuron
• Thallium
• Tetramethylene disulfotetramine
• Sodium fluoroacetate
• Scilliroside
• Zyklon B (hydrogen cyanide)

All are poisons and should be handled carefully.

What are the applications of ozone?

Ozone is a pollutant, but it has many industrial applications. They include:.

• As a disinfectant in hospitals, food processing factories and aged care homes
• Water disinfectant in place of chlorine, also in swimming pools
• To kill bacteria in food
• Washing of fresh fruits and vegetables to kill bacteria, mould and yeast
• In chemical synthesis in the industry
• Used to remove the contaminants such as iron, arsenic, hydrogen sulphide and nitrites in water
• Clean and bleach industrial plants.
• In processing plastics
• Ozone is also used in bleaching wood pulp.
• It is also used to detoxify cyanide wastes from gold and silver mining.

There are several other applications because of the high oxidation potential of ozone.

What are the common toxic heavy metals in our food?

Although iron is essential it is also toxic and the toxic metals include:

• Arsenic
• Lead
• Mercury
• Cadmium
• Iron
• Aluminium

Arsenic - It is the most common cause of acute heavy metal poisoning. It is released from different industries to the environment. Shellfish, cod and haddock contain arsenic. Paints, rat poison, fungicides are the other sources. The target organs are kidneys, central nervous system, digestive tract and skin.

Lead - It accounts for most of the cases of paediatric heavy metal poisoning. It reduces the intelligence of the children. The old houses still have the lead pipes. Industry produces every year 2.5 million tons of lead and most of this is used in batteries. Bones, brain, kidneys and thyroid gland are the target organs. The paints also contain lead salts to dry them quickly. Therefore children should not be allowed to lick painted doors or windows. It is a problem throughout the world. Back hair dye and black printing ink have also lead.

Mercury - Its emissions are there from nature as well as from the industry. Chloralkali plants and paper industries are significant polluters. Dental amalgam is also a source of pollution. Fishes have more mercury. Target organs are the brain and kidneys. The present problem of mercury in our environment is the incandescent light bulbs, which we use in our houses. Some politicians want to ban these bulbs because they consume much more electricity. Politics and industry, therefore, recommend energy saving compact fluorescent light (CFL) bulbs. But, the problem is they keep silent about the mercury present in these energy saving CFL bulbs which then could become one of the serious environmental contamination to our soil and ground water. When these bulbs are used up, they form solid wastes. In Western countries we can give back fused bulbs where we bought them and it is the law which regulates this. What will happen in other countries where there are no such possibilities? People simply throw used up bulbs with their household waste or near their houses, the mercury goes to the soil and ground water. The plants take these metals and the animals along with their feed or grass and we are the last in this chain to get it from our food. We must be very careful to keep ourselves and our families free from such poisons.

Cadmium - it is used in nickel-cadmium batteries, PVC plastics and paint pigments. Cigarette (tobacco) also contains cadmium. The absorption is through respiratory system. Liver, placenta, kidneys, lungs, brain and bones are the target organs.

Iron - it is a heavy metal of concern because iron supplements may acutely poison young children, 5 to 9 years. If the children consume 30mg iron tablets per day, it may spoil their health. The health problems associated with free radicals are dangerous to children. Too much of iron supplement is not healthy for adults. It accumulates in liver, heart muscles, kidney and other organs, rusting a reddish brown oxide coating forms on iron by the action of oxygen and moisture there and producing countless number of free radicals.

Aluminium - it is not a heavy metal but it is ingested through the use of food additives, antacids, nasal sprays and antiperspirants. Other sources are drinking water automobile exhaust, tobacco smoke, aluminium foil, aluminium cookware, ceramics and fancy fire works. Target organs for aluminium are the central nervous system, kidney and digestive system. The question of Aluminium and Alzheimer’s disease is not yet answered. It is proved that aluminium could cross the blood-brain barrier without any problem.

Fish and omega-3 fatty acids – what is the origin of these fatty acids?

It is a good question. The human beings could not synthesize the omega-3 fatty acids. That is why we have to take them from our food.

Salmon, herring, mackerel, sardines and anchovies are rich in omega-3 fatty acids. Other fatty fish have lesser amounts of omega-3 fatty acids. The important question is whether the fish could synthesize omega-3 fatty acids or not.

The fish could not synthesize the omega-3 fatty acids like human beings. What is the origin of omega-3 fatty acid then? The orign is the food habits of fish. Their diets contain much plankton and algae and the fish gets the omega-3 fatty acids from them.

Fish is very healthy, but some precautions must be taken by us. Too much of fatty fish are not good for our health. It is because they could contain lot of poisonous heavy metals like cadmium, arsenic, mercury etc. and the fat soluble chlorinated chemicals like many pesticides, PCBs and dioxins.

But the benefits of fish intake generally outweigh the potential risks. But persons with problems with environmental poisons must be careful with fish consumption. As you know always the dose makes the poison. Twice in a week, 150 to 200 g fish is good for all.