Analysis of Water from Georges Pond – September 2009

Criterion (Analyte)	South Shore Colony	138 Cousins	North (Town) Beach	Hall	Northwest Georges Pond Road	East 200 Georges Pond Road	Positive Control
pH (acidity)(1)	6.5	6.5	6.5	7	6.5	6.5	N/A
NO3- (nitrate) as nitrogen	N.D. (2)	N.D.	N.D.	N.D.	N.D.	N.D.	~5 ppm ~15 ppm
NO2^-(nitrite) as nitrogen	N.D. (3)	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.
PO4^-3 as total inorganic phosphate (4)	0.1 + or - 0.4	0.1 + or - 0.4	0.4 + or - 0.4	1.4 + or - 0.4	0.4 + or - 0.4	1.4 + or - 0.4	N/A
Detergent	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.	1.3 ppm(5)
Dissolved oxygen	>>1.0 mg/l (6)	>>1.0 mg/l	>>1.0 mg/l	>>1.0 mg/l	>>1.0 mg/l	>>1.0 mg/l	N.A.

(1) A pH of 7.0 is neutral; lower is more acid, higher is more alkaline. The pH of our stomachs is about 2 (strongly acidic); the pH of our blood is about 7 (neutral).

(2) N.D. = none detected; in this case less than 1 part per million (ppm).

(3) None detected; in this case less than 0.01 ppm

(4) These results are at the close to or at the lower limit of detection. The extent of uncertainty is shown.

(5) I added 1 drop of Joy (dishwasher detergent) to 1 liter of water to obtain the 1.3 ppm result.

(6) >> means much over, to be expected for surface waters. mg/l means milligrams/liter. A mg is a thousandth of a gram = 1/28 thousandth of an ounce. mg/l and ppm (parts per million) are equivalent. I ordered the low-range scale because I did not know what to expect at the surface, but knew we would need it when sampling deeper waters.