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Case study 7: N Environmentalist

You have been asked by E Regulator to attend the meeting because of your knowledge of environmental sampling issues. You have to give a short talk about some of the problems of environmental sampling for aluminium fluoride dust on grass.

You know that obtaining representative grass samples coated with aluminium fluoride dust is difficult because of the effect of environmental factors:

• Wind direction - more dust will settle on the vegetation located to the windward side of the plant.
• Rain - washes the dust off the grass into the soil.
• Animals - for example cows can urinate and defecate on the grass causing the dust to be displaced from the grass.
• Time of year - grass grows very slowly in the winter so fluoride concentrations tend to be much higher.

Other factors to be taken into account when analysing fluoride concentrations in grass in this type of situation are:

• The concentration of fluoride in the soil does not significantly affect the fluoride concentration of the grass.
• Most of the fluoride found on the grass comes from emissions from local industry.
• Evidence shows that though ingestion of vegetation containing high concentrations of fluoride leads to high levels of fluoride in the urine and in the bones of the animal, the concentration of fluoride in milk remains very low.
• It is usually assumed that the inhalation of fluoride from the atmosphere contributes a negligible amount to the total fluoride intake of animals in an area of industrial pollution.
• In your experience not all analytical laboratories have good quality assurance and quality control procedures. This means that there is a concern about the reliability of the analytical results for such laboratories.

You know that A N List is very young and graduated from the University of the Isles of Scilly, not a very good university in your opinion. You suspect that there may be problems with some of the analysis. You are suspicious why there is no result for February (missing data often means that someone has made a mistake) and you want to get to the bottom of this.

You are concerned about the relationship between E Regulator and Al Manufacturer and think that they might have done a deal on emission limits for aluminium fluoride dust without involving anyone else in the decision.