Document ID: EPA-HQ-OAR-2005-0083-0404
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-09-18T04:00Z

SEQ CHAPTER \h \r 1 Historical Summary of Strontium-90 in Milk

Surrounding the New Jersey / New York City Metropolitan Area

J. Scott Telofski, PE

National Air and Radiation Environmental Laboratory

United States Environmental Protection Agency

February 8, 2001

	Executive Summary

In the late 1950s, the United States Public Health Service (PHS) Milk
Monitoring Network was developed and consisted of as many as twelve
stations.  The purpose of the network was to determine trends of
radioactive materials in milk.  By summer of 1960, the network was
expanded to approximately 60 stations.  One of the radionuclides that
the milk was tested for was strontium-90.  In 1970, the responsibility
for collecting, analyzing, and interpreting environmental radiation
levels was transferred to the United States Environmental Protection
Agency (EPA).

In response to local and state agency requests, EPA Region 2 requested
EPA’s National Air and Radiation Environmental Laboratory (NAREL) to
compile the historical data for strontium-90 in environmental samples. 
The results of strontium-90 in milk analyses for sampling locations in
or near the New Jersey / New York City area have been tabulated and
graphed.  The cities include New York, Philadelphia, Trenton, Baltimore,
Hartford, and Wilmington.

It is apparent that Sr-90 concentrations in milk were highest during the
atmospheric testing period of the early 1960s.  After most above-ground
testing ceased, the levels of strontium-90 continually decline. 
Individual stations may show some increase due to non-Soviet and non-US
testing that was conducted after 1962, as well as from the Chernobyl
nuclear reactor accident.  This can be seen in the graphs shown in
Appendix B.  The composite graph shows that similar trends in Sr-90
concentrations in milk exist for all of the cities included in this
report, and the national average graph shows similar trends and levels
across the nation.

Introduction

In the late 1950s, the United States Public Health Service (PHS) Milk
Monitoring Network was developed and consisted of as many as twelve
stations.  The purpose of the network was to determine trends of
radioactive materials in milk.  Milk was chosen to be sampled since it
is an important element of the diet and is constantly available at all
seasons of the year and in all climates.  By summer of 1960, the network
was expanded to approximately 60 stations.  One of the radionuclides
that the milk was tested for was strontium-90.

In 1970, the responsibility for collecting, analyzing, and interpreting
environmental radiation levels was transferred to the United States
Environmental Protection Agency (EPA).  The EPA operated the monitoring
program out of the Radiation Office.  The daily operations of the
program were run by the Eastern Environmental Radiation Facility, now
the National Air and Radiation Environmental Laboratory (NAREL).  The
NAREL continues to runs the daily operations of the program. 

In response to local and state agency requests, EPA Region 2 requested
EPA’s National Air and Radiation Environmental Laboratory (NAREL) to
compile the historical data for strontium-90 in environmental samples. 
The results of strontium-90 in milk analyses for sampling locations in
or near the New Jersey / New York City area have been tabulated and
graphed.  The cities include New York, Philadelphia, Trenton, Baltimore,
Hartford, and Wilmington.

Sample Collection and Sources of Data

Throughout the 1960s, one or more milk samples were collected at a given
location in a month.  Each sample represents a composite, according to
production, from the suppliers of at least 80% of the milk consumed in a
given population center.  These individual milk samples were often
composited into one monthly sample to reduce analytical load, or they
may have been analyzed individually.  The results were reported in the
Radiological Health Data and Reports (sometimes titled Radiation Data
and Reports or Radiological Health Data) as average values for the
individual samples or as the concentration of the composite for that
month.  Only the month and year are published for these data. 
Therefore, for data reporting purposes, it is assumed that this
concentration can be applied to the middle (15th) of the respective
month.

The sampling program began with sampling of raw milk.  In 1960, when the
program was expanded to approximately 60 stations, pasteurized milk was
collected at the expansion locations, which sometimes included locations
where raw milk was also collected.  The duplication in milk sampling was
performed to determine if there were differences between raw and
pasteurized milk.  In December 1961, it was determined that there were
no significant differences in the results between raw milk samples and
pasteurized milk samples.  The collection of raw milk was discontinued
at that time.  However, only pasteurized milk samples are considered in
this report since all locations covered in this report did not
participate in the raw milk sampling program of the 1950s.

In July 1970, milk sample collection remained monthly, but analysis
frequency for strontium-90 was reduced to January, April, July, and
October (i.e., quarterly) analyses.  Beginning in July 1973, only the
July sample was routinely analyzed for strontium-90 (i.e., one
strontium-90 analysis per year).  Additional samples and analyses were
conducted in response to Chinese nuclear weapons tests (1976 and 1977)
and the Chernobyl nuclear reactor accident (1986).

Radiological Health Data and Reports contains the results of samples
collected through July 1974.  Beginning with samples collected in August
1974, the results were published in quarterly publications titled
Environmental Radiation Data (ERD) reports (since strontium-90 analysis
were quarterly, the first results are published in ERD for October
1974).  Beginning in 1978, the results are also stored in NAREL’s
electronic database.  Since all results of samples prior to the 1978
electronic database results are only present in print form, the results
were manually entered into electronic forms which created a database of
the results.  Results which are available from the NAREL’s electronic
database have been directly extracted electronically.  In situations
where more than one verified result exists in the NAREL electronic
database (e.g., replicate analysis for quality assurance purposes) the
results from the first analysis are used.

Uncertainty and Minimum Detectable Concentration Data

Data obtained from the Radiological Health Data and Reports did not have
sample specific uncertainties associated with the concentrations.  In
the October 1961 Radiological Health Data and Report, a Minimum
Detectable Concentration (MDC) value for Sr-90 was stated to be 1 pCi/L.
 This MDC was based upon the point where the 2-F uncertainty equaled
100%.  The following is the reported relationship between concentration
and uncertainty for Sr-90.

	Nuclide	2F = 100% (pCi/L)	2F = 50% (pCi/L)	2F = 10% (pCi/L)

	Sr-90	1	2	20

In the March 1964 report, new uncertainty information was provided, as
shown below.  Since these uncertainties were based upon additional
information and analyses, it was assumed that they were potentially more
accurate, and therefore were used for determining uncertainty and MDC
for all data prior to the March 1964 report as well as all subsequent
data found in the Radiological Health Data and Reports.

	Nuclide	Conc Range and (2F)	Conc Range and (2F)	MDC (pCi/L)

	Sr-90	0-20 ("2)	>20 ("10%)	2

Beginning with publication of the Environmental Radiation Data reports,
sample specific uncertainties were published along with each
concentration.  These uncertainties were input into the database. 
However, no MDC values were provided, so the MDC of 2 pCi/L was used. 
The data which were available in NAREL’s electronic database contained
sample specific uncertainties which were extracted from the database. 
However, until about 1994, the electronic database does not include
sample specific MDC values.  Therefore, it has been assumed that the MDC
should remain at 2 pCi/L until sample specific MDC values are present in
the electronic database.

Results

The results of Sr-90 in milk analyses for cities in or near the New
Jersey / New York area have been tabulated and graphed.  These cities
include New York, Philadelphia, Trenton, Baltimore, Hartford, and
Wilmington.  Appendices A1 through A6 contain tables of the Sr-90
results for the period from 1960 through 1997 for each city.  Graphs of
these data for each city, a composite of all six cities on one graph,
and a graph of the average of all stations across the nation are shown
in Appendix B.

It is apparent that Sr-90 concentrations in milk were highest during the
atmospheric testing period of the early 1960s.  After most above-ground
testing ceased, the levels of strontium-90 continually decline. 
Individual stations may show some increase due to non-Soviet and non-US
testing that was conducted after 1962, as well as from the Chernobyl
nuclear reactor accident.  This can be seen in the graphs shown in
Appendix B.  The composite graph shows that similar trends in Sr-90
concentrations in milk exist for all of the cities included in this
report.  The national average graph shows similar trends and levels
across the nation.

	APPENDIX A1

	Data Tables for New York, NY

Sr-90 in Milk Results

New York, NY

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

June 15, 1960	11	2	2

July 15, 1960	12	2	2

August 15, 1960	8	2	2

September 15, 1960	8	2	2

October 15, 1960	8	2	2

November 15, 1960	10	2	2

December 15, 1960	7	2	2

February 15, 1961	6	2	2

March 15, 1961	8	2	2

April 15, 1961	8	2	2

May 15, 1961	10	2	2

June 15, 1961	10	2	2

July 15, 1961	10	2	2

August 15, 1961	6	2	2

September 15, 1961	10	2	2

October 15, 1961	8	2	2

November 15, 1961	8	2	2

December 15, 1961	9	2	2

January 15, 1962	12	2	2

February 15, 1962	8	2	2

March 15, 1962	8	2	2

April 15, 1962	9	2	2

May 15, 1962	14	2	2

June 15, 1962	14	2	2

July 15, 1962	15	2	2

August 15, 1962	14	2	2

September 15, 1962	20	2	2

October 15, 1962	23	2.3	2

November 15, 1962	16	2	2

December 15, 1962	11	2	2

January 15, 1963	16	2	2

February 15, 1963	15	2	2

March 15, 1963	16	2	2

April 15, 1963	13	2	2

May 15, 1963	22	2.2	2

June 15, 1963	38	3.8	2

July 15, 1963	44	4.4	2

August 15, 1963	42	4.2	2

September 15, 1963	37	3.7	2

October 15, 1963	32	3.2	2

November 15, 1963	31	3.1	2

December 15, 1963	28	2.8	2

January 15, 1964	28	2.8	2

February 15, 1964	26	2.6	2

March 15, 1964	22	2.2	2

April 15, 1964	25	2.5	2

May 15, 1964	28	2.8	2

June 15, 1964	36	3.6	2

July 15, 1964	32	3.2	2

August 15, 1964	23	2.3	2

September 15, 1964	19	2	2

October 15, 1964	18	2	2

November 15, 1964	22	2.2	2

December 15, 1964	18	2	2

January 15, 1965	16	2	2

February 15, 1965	20	2	2

March 15, 1965	21	2.1	2

April 15, 1965	19	2	2

May 15, 1965	21	2.1	2

June 15, 1965	22	2.2	2

July 15, 1965	20	2	2

August 15, 1965	16	2	2

September 15, 1965	15	2	2

October 15, 1965	15	2	2

November 15, 1965	14	2	2

December 15, 1965	13	2	2

January 15, 1966	13	2	2

February 15, 1966	13	2	2

March 15, 1966	13	2	2

April 15, 1966	13	2	2

May 15, 1966	15	2	2

June 15, 1966	17	2	2

July 15, 1966	15	2	2

August 15, 1966	15	2	2

September 15, 1966	12	2	2

October 15, 1966	11	2	2

November 15, 1966	13	2	2

December 15, 1966	12	2	2

January 15, 1967	12	2	2

February 15, 1967	10	2	2

March 15, 1967	11	2	2

April 15, 1967	11	2	2

May 15, 1967	13	2	2

June 15, 1967	11	2	2

July 15, 1967	15	2	2

August 15, 1967	9	2	2

September 15, 1967	11	2	2

October 15, 1967	9.9	2	2

November 15, 1967	8	2	2

December 15, 1967	9	2	2

January 15, 1968	11	2	2

February 15, 1968	8	2	2

March 15, 1968	7	2	2

April 15, 1968	11	2	2

May 15, 1968	14	2	2

June 15, 1968	19	2	2

July 15, 1968	18	2	2

August 15, 1968	14	2	2

September 15, 1968	12	2	2

October 15, 1968	7	2	2

November 15, 1968	9	2	2

December 15, 1968	9	2	2

February 15, 1969	7	2	2

March 15, 1969	8	2	2

April 15, 1969	11	2	2

May 15, 1969	10	2	2

June 15, 1969	12	2	2

July 15, 1969	11	2	2

August 15, 1969	13	2	2

September 15, 1969	12	2	2

October 15, 1969	8	2	2

November 15, 1969	9	2	2

December 15, 1969	9	2	2

January 15, 1970	5	2	2

February 15, 1970	7	2	2

March 15, 1970	10	2	2

April 15, 1970	9	2	2

May 15, 1970	9	2	2

June 15, 1970	13	2	2

July 15, 1970	13	2	2

October 15, 1970	8	2	2

January 15, 1971	9	2	2

April 15, 1971	8	2	2

July 15, 1971	9	2	2

October 15, 1971	7	2	2

January 15, 1972	7	2	2

April 15, 1972	6	2	2

July 15, 1972	12	2	2

October 15, 1972	8	2	2

January 15, 1973	7	2	2

April 15, 1973	4	2	2

July 15, 1973	4	2	2

July 15, 1974	9	2	2

July 15, 1975	7	1.5	2

July 15, 1976	6.9	2	2

October 15, 1976	5.8	0.8	2

July 15, 1977	6.2	1.2	2

October 03, 1977	5.1	0.8	2

October 11, 1977	6.4	0.8	2

October 17, 1977	6.4	0.8	2

October 24, 1977	4.8	0.8	2

July 15, 1978	4.2	1	2

July 02, 1979	7.9	1	2

July 07, 1980	4.4	1.2	2

July 06, 1981	4.2	1.1	2

July 12, 1982	3.1	1.2	2

July 11, 1983	2.33	0.28	2

July 02, 1984	3.82	0.93	2

July 01, 1985	1.75	0.57	2

May 05, 1986	2.7	0.51	2

May 15, 1986	3.38	0.78	2

May 25, 1986	2.9	1.2	2

June 01, 1986	3.5	2	2

June 10, 1986	4.33	0.6	2

June 17, 1986	3.73	0.43	2

July 07, 1986	4.28	0.91	2

July 06, 1987	2.7	0.65	2

July 11, 1988	2.24	0.9	2

July 03, 1989	1.1	1.1	2

July 02, 1990	2.09	0.99	2

July 01, 1991	1.855	0.056	2

July 06, 1992	1.903	0.0041	2

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX A2

	Data Tables for Philadelphia, PA

Sr-90 in Milk Results

Philadelphia, PA

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

June 15, 1960	10	2	2

July 15, 1960	11	2	2

August 15, 1960	10	2	2

September 15, 1960	7	2	2

October 15, 1960	6	2	2

November 15, 1960	6	2	2

December 15, 1960	7	2	2

January 15, 1961	6	2	2

February 15, 1961	8	2	2

March 15, 1961	7	2	2

April 15, 1961	9	2	2

May 15, 1961	8	2	2

June 15, 1961	11	2	2

July 15, 1961	10	2	2

August 15, 1961	9	2	2

September 15, 1961	6	2	2

October 15, 1961	7	2	2

November 15, 1961	8	2	2

December 15, 1961	9	2	2

January 15, 1962	8	2	2

February 15, 1962	9	2	2

March 15, 1962	10	2	2

April 15, 1962	11	2	2

May 15, 1962	15	2	2

June 15, 1962	13	2	2

July 15, 1962	14	2	2

August 15, 1962	10	2	2

September 15, 1962	17	2	2

October 15, 1962	15	2	2

November 15, 1962	15	2	2

December 15, 1962	11	2	2

January 15, 1963	18	2	2

February 15, 1963	22	2.2	2

March 15, 1963	13	2	2

April 15, 1963	18	2	2

May 15, 1963	30	3	2

June 15, 1963	39	3.9	2

July 15, 1963	30	3	2

August 15, 1963	25	2.5	2

September 15, 1963	22	2.2	2

October 15, 1963	21	2.1	2

November 15, 1963	21	2.1	2

December 15, 1963	21	2.1	2

January 15, 1964	20	2	2

February 15, 1964	19	2	2

March 15, 1964	20	2	2

April 15, 1964	22	2.2	2

May 15, 1964	28	2.8	2

June 15, 1964	26	2.6	2

July 15, 1964	21	2.1	2

August 15, 1964	17	2	2

September 15, 1964	16	2	2

October 15, 1964	15	2	2

November 15, 1964	16	2	2

December 15, 1964	16	2	2

January 15, 1965	16	2	2

February 15, 1965	18	2	2

March 15, 1965	17	2	2

April 15, 1965	18	2	2

May 15, 1965	20	2	2

June 15, 1965	18	2	2

July 15, 1965	15	2	2

August 15, 1965	13	2	2

September 15, 1965	12	2	2

October 15, 1965	13	2	2

November 15, 1965	11	2	2

December 15, 1965	11	2	2

January 15, 1966	11	2	2

February 15, 1966	12	2	2

March 15, 1966	12	2	2

April 15, 1966	14	2	2

May 15, 1966	14	2	2

June 15, 1966	14	2	2

July 15, 1966	13	2	2

August 15, 1966	12	2	2

September 15, 1966	10	2	2

October 15, 1966	11	2	2

November 15, 1966	10	2	2

December 15, 1966	11	2	2

January 15, 1967	12	2	2

February 15, 1967	11	2	2

March 15, 1967	11	2	2

April 15, 1967	10	2	2

May 15, 1967	9	2	2

June 15, 1967	11	2	2

July 15, 1967	9	2	2

August 15, 1967	9	2	2

September 15, 1967	9	2	2

October 15, 1967	9.3	2	2

November 15, 1967	8	2	2

December 15, 1967	6	2	2

January 15, 1968	10	2	2

February 15, 1968	9	2	2

March 15, 1968	8	2	2

April 15, 1968	0	2	2

May 15, 1968	11	2	2

June 15, 1968	16	2	2

July 15, 1968	14	2	2

August 15, 1968	12	2	2

September 15, 1968	8	2	2

October 15, 1968	6	2	2

November 15, 1968	7	2	2

December 15, 1968	8	2	2

January 15, 1969	9	2	2

February 15, 1969	8	2	2

March 15, 1969	10	2	2

April 15, 1969	8	2	2

May 15, 1969	9	2	2

June 15, 1969	9	2	2

August 15, 1969	11	2	2

September 15, 1969	10	2	2

October 15, 1969	11	2	2

November 15, 1969	9	2	2

December 15, 1969	9	2	2

January 15, 1970	9	2	2

February 15, 1970	7	2	2

March 15, 1970	8	2	2

April 15, 1970	8	2	2

May 15, 1970	9	2	2

June 15, 1970	9	2	2

July 15, 1970	12	2	2

October 15, 1970	8	2	2

April 15, 1971	7	2	2

June 15, 1971	0	0	2

July 15, 1971	10	2	2

October 15, 1971	7	2	2

April 15, 1972	5	2	2

July 15, 1972	8	2	2

October 15, 1972	6	2	2

January 15, 1973	4	2	2

April 15, 1973	5	2	2

July 15, 1973	5	2	2

July 15, 1974	5	2	2

July 15, 1975	4.4	1.2	2

July 15, 1976	4.7	1	2

October 08, 1976	4.6	0.6	2

October 12, 1976	4.3	0.7	2

October 13, 1976	4.1	0.9	2

October 15, 1976	3.2	0.4	2

October 22, 1976	4.1	0.5	2

October 29, 1976	5.5	0.7	2

November 08, 1976	5.1	0.7	2

December 03, 1976	5	0.7	2

July 15, 1977	5.7	1.5	2

October 03, 1977	3.7	0.8	2

October 11, 1977	4.9	1	2

July 15, 1978	4.9	1.3	2

July 03, 1979	4.4	1	2

July 07, 1980	5	1.8	2

July 06, 1981	2.99	0.81	2

July 06, 1982	3.9	1.3	2

August 08, 1983	3	1.4	2

July 02, 1984	2.77	0.46	2

July 08, 1985	2.69	0.63	2

May 05, 1986	2.56	0.31	2

May 15, 1986	2.4	1.1	2

May 22, 1986	1.41	0.45	2

June 02, 1986	2.25	0.28	2

June 07, 1986	1.6	1.2	2

June 16, 1986	2.26	0.35	2

July 06, 1987	1	2.4	2

July 05, 1988	2.01	0.69	2

July 05, 1989	1.2	0.49	2

July 02, 1990	1	2.4	2

July 08, 1991	2.13	0.55	2

July 08, 1992	1.53	0.46	2

July 06, 1993	1.46	0.48	2

July 06, 1994	1.19	0.49	0.6

July 07, 1995	1.26	0.57	0.739

July 08, 1996	1.56	0.53	0.6531

July 14, 1997	0.84	0.57	0.8412

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX A3

	Data Tables for Trenton, NJ

Sr-90 in Milk Results

Trenton, NJ

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

June 15, 1960	10	2	2

July 15, 1960	8	2	2

August 15, 1960	7	2	2

September 15, 1960	7	2	2

October 15, 1960	8	2	2

November 15, 1960	10	2	2

December 15, 1960	6	2	2

January 15, 1961	6	2	2

February 15, 1961	6	2	2

March 15, 1961	9	2	2

April 15, 1961	8	2	2

May 15, 1961	8	2	2

June 15, 1961	10	2	2

July 15, 1961	8	2	2

August 15, 1961	8	2	2

September 15, 1961	8	2	2

October 15, 1961	8	2	2

November 15, 1961	10	2	2

December 15, 1961	8	2	2

January 15, 1962	8	2	2

February 15, 1962	9	2	2

March 15, 1962	8	2	2

April 15, 1962	8	2	2

May 15, 1962	11	2	2

June 15, 1962	12	2	2

July 15, 1962	10	2	2

August 15, 1962	9	2	2

September 15, 1962	18	2	2

October 15, 1962	14	2	2

November 15, 1962	16	2	2

December 15, 1962	8	2	2

January 15, 1963	14	2	2

February 15, 1963	10	2	2

March 15, 1963	14	2	2

April 15, 1963	19	2	2

May 15, 1963	25	2.5	2

June 15, 1963	33	3.3	2

July 15, 1963	32	3.2	2

August 15, 1963	25	2.5	2

September 15, 1963	22	2.2	2

October 15, 1963	19	2	2

November 15, 1963	18	2	2

December 15, 1963	19	2	2

January 15, 1964	20	2	2

February 15, 1964	17	2	2

March 15, 1964	18	2	2

April 15, 1964	18	2	2

May 15, 1964	25	2.5	2

June 15, 1964	25	2.5	2

July 15, 1964	23	2.3	2

August 15, 1964	16	2	2

September 15, 1964	16	2	2

October 15, 1964	14	2	2

November 15, 1964	17	2	2

December 15, 1964	14	2	2

January 15, 1965	14	2	2

February 15, 1965	18	2	2

March 15, 1965	16	2	2

April 15, 1965	16	2	2

May 15, 1965	15	2	2

June 15, 1965	16	2	2

July 15, 1965	16	2	2

August 15, 1965	14	2	2

September 15, 1965	12	2	2

October 15, 1965	11	2	2

November 15, 1965	11	2	2

December 15, 1965	12	2	2

January 15, 1966	10	2	2

February 15, 1966	14	2	2

March 15, 1966	11	2	2

April 15, 1966	14	2	2

May 15, 1966	11	2	2

June 15, 1966	14	2	2

July 15, 1966	12	2	2

August 15, 1966	11	2	2

September 15, 1966	10	2	2

October 15, 1966	10	2	2

November 15, 1966	10	2	2

December 15, 1966	11	2	2

January 15, 1967	10	2	2

February 15, 1967	10	2	2

March 15, 1967	10	2	2

April 15, 1967	10	2	2

May 15, 1967	10	2	2

June 15, 1967	11	2	2

July 15, 1967	10	2	2

August 15, 1967	9	2	2

September 15, 1967	10	2	2

October 15, 1967	9.6	2	2

November 15, 1967	11	2	2

December 15, 1967	8	2	2

January 15, 1968	9	2	2

February 15, 1968	8	2	2

March 15, 1968	8	2	2

April 15, 1968	14	2	2

May 15, 1968	9	2	2

June 15, 1968	15	2	2

July 15, 1968	12	2	2

August 15, 1968	11	2	2

September 15, 1968	8	2	2

October 15, 1968	6	2	2

November 15, 1968	9	2	2

December 15, 1968	10	2	2

January 15, 1969	9	2	2

February 15, 1969	7	2	2

March 15, 1969	8	2	2

April 15, 1969	9	2	2

May 15, 1969	9	2	2

June 15, 1969	10	2	2

July 15, 1969	9	2	2

August 15, 1969	13	2	2

September 15, 1969	9	2	2

October 15, 1969	9	2	2

November 15, 1969	8	2	2

December 15, 1969	7	2	2

January 15, 1970	8	2	2

February 15, 1970	10	2	2

March 15, 1970	7	2	2

April 15, 1970	0	2	2

May 15, 1970	8	2	2

June 15, 1970	8	2	2

July 15, 1970	11	2	2

October 15, 1970	8	2	2

January 15, 1971	7	2	2

April 15, 1971	10	2	2

July 15, 1971	9	2	2

October 15, 1971	7	2	2

January 15, 1972	6	2	2

April 15, 1972	8	2	2

July 15, 1972	6	2	2

October 15, 1972	7	2	2

January 15, 1973	6	2	2

April 15, 1973	6	2	2

July 15, 1973	4	2	2

July 15, 1975	5.7	1.6	2

July 15, 1976	4	1	2

October 22, 1976	5	0.5	2

November 01, 1976	7.5	0.9	2

July 15, 1977	5.1	1.2	2

October 03, 1977	4.4	0.8	2

October 11, 1977	6.6	1	2

October 17, 1977	4.1	0.7	2

July 15, 1978	4.8	1.3	2

July 20, 1979	4.6	1	2

July 11, 1980	4.6	1.4	2

July 09, 1981	4.6	1.2	2

July 01, 1982	3.4	1.1	2

July 07, 1983	4.27	0.89	2

July 05, 1984	2.4	1.3	2

July 10, 1985	2.54	0.37	2

May 06, 1986	3	1.4	2

May 15, 1986	0.18	0.64	2

May 25, 1986	2.4	1	2

June 01, 1986	3.4	0.37	2

June 15, 1986	2.73	0.29	2

July 01, 1986	-0.2	0.46	2

July 08, 1987	3	0.37	2

July 06, 1988	1.84	0.97	2

July 05, 1989	1.7	1.5	2

July 03, 1990	2.1	0.13	2

July 03, 1991	2.16	0.92	2

July 09, 1992	0.84	0.11	2

July 08, 1993	1.16	0.59	2

July 07, 1994	1.44	0.5	0.58

July 07, 1995	1.26	0.54	0.679

July 02, 1996	1.55	0.57	0.754

July 18, 1997	0.75	0.57	0.8726

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX A4 

	Data Tables for Baltimore, MD

Sr-90 in Milk Results

Baltimore, MD

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

August 15, 1960	6	2	2

September 15, 1960	7	2	2

October 15, 1960	8	2	2

November 15, 1960	7	2	2

December 15, 1960	10	2	2

January 15, 1961	6	2	2

February 15, 1961	6	2	2

March 15, 1961	6	2	2

April 15, 1961	7	2	2

May 15, 1961	7	2	2

June 15, 1961	10	2	2

July 15, 1961	12	2	2

August 15, 1961	10	2	2

September 15, 1961	8	2	2

October 15, 1961	8	2	2

November 15, 1961	7	2	2

December 15, 1961	8	2	2

January 15, 1962	10	2	2

February 15, 1962	9	2	2

March 15, 1962	8	2	2

April 15, 1962	11	2	2

May 15, 1962	17	2	2

June 15, 1962	17	2	2

July 15, 1962	16	2	2

August 15, 1962	20	2	2

September 15, 1962	18	2	2

October 15, 1962	18	2	2

November 15, 1962	17	2	2

December 15, 1962	17	2	2

January 15, 1963	15	2	2

February 15, 1963	14	2	2

March 15, 1963	12	2	2

April 15, 1963	15	2	2

May 15, 1963	26	2.6	2

June 15, 1963	30	3	2

July 15, 1963	28	2.8	2

August 15, 1963	26	2.6	2

September 15, 1963	22	2.2	2

October 15, 1963	20	2	2

November 15, 1963	19	2	2

December 15, 1963	21	2.1	2

January 15, 1964	19	2	2

February 15, 1964	20	2	2

March 15, 1964	22	2.2	2

April 15, 1964	22	2.2	2

May 15, 1964	30	3	2

June 15, 1964	31	3.1	2

July 15, 1964	26	2.6	2

August 15, 1964	20	2	2

September 15, 1964	18	2	2

October 15, 1964	18	2	2

November 15, 1964	19	2	2

December 15, 1964	18	2	2

January 15, 1965	17	2	2

February 15, 1965	18	2	2

March 15, 1965	18	2	2

April 15, 1965	18	2	2

May 15, 1965	21	2.1	2

June 15, 1965	19	2	2

July 15, 1965	17	2	2

August 15, 1965	14	2	2

September 15, 1965	14	2	2

October 15, 1965	16	2	2

November 15, 1965	15	2	2

December 15, 1965	17	2	2

January 15, 1966	13	2	2

February 15, 1966	13	2	2

March 15, 1966	13	2	2

April 15, 1966	13	2	2

May 15, 1966	16	2	2

June 15, 1966	17	2	2

July 15, 1966	13	2	2

August 15, 1966	12	2	2

September 15, 1966	12	2	2

October 15, 1966	12	2	2

November 15, 1966	11	2	2

December 15, 1966	10	2	2

January 15, 1967	12	2	2

February 15, 1967	11	2	2

March 15, 1967	11	2	2

April 15, 1967	12	2	2

May 15, 1967	13	2	2

June 15, 1967	13	2	2

July 15, 1967	11	2	2

August 15, 1967	10	2	2

September 15, 1967	11	2	2

October 15, 1967	10.9	2	2

November 15, 1967	10	2	2

December 15, 1967	10	2	2

January 15, 1968	9	2	2

February 15, 1968	8	2	2

March 15, 1968	7	2	2

April 15, 1968	11	2	2

May 15, 1968	9	2	2

June 15, 1968	14	2	2

July 15, 1968	12	2	2

August 15, 1968	13	2	2

September 15, 1968	9	2	2

October 15, 1968	9	2	2

November 15, 1968	11	2	2

December 15, 1968	9	2	2

January 15, 1969	8	2	2

February 15, 1969	7	2	2

March 15, 1969	6	2	2

April 15, 1969	8	2	2

May 15, 1969	11	2	2

June 15, 1969	9	2	2

July 15, 1969	11	2	2

August 15, 1969	8	2	2

September 15, 1969	7	2	2

October 15, 1969	11	2	2

November 15, 1969	8	2	2

December 15, 1969	6	2	2

January 15, 1970	9	2	2

February 15, 1970	6	2	2

March 15, 1970	6	2	2

April 15, 1970	5	2	2

May 15, 1970	9	2	2

June 15, 1970	10	2	2

July 15, 1970	8	2	2

October 15, 1970	7	2	2

January 15, 1971	9	2	2

April 15, 1971	7	2	2

July 15, 1971	10	2	2

October 15, 1971	8	2	2

January 15, 1972	7	2	2

April 15, 1972	6	2	2

July 15, 1972	7	2	2

October 15, 1972	7	2	2

January 15, 1973	5	2	2

April 15, 1973	4	2	2

July 15, 1973	8	2	2

July 15, 1974	5	2	2

July 15, 1975	5.2	1.7	2

July 15, 1976	5.2	1.6	2

October 08, 1976	6.1	0.6	2

October 15, 1976	5.5	0.6	2

November 05, 1976	5.5	0.7	2

December 03, 1976	5.8	0.7	2

July 15, 1977	5.2	1.3	2

October 03, 1977	3.7	0.7	2

October 10, 1977	4.1	0.8	2

October 17, 1977	3.7	0.8	2

October 24, 1977	4.4	1	2

July 15, 1978	5	1.5	2

July 06, 1979	4.3	1	2

July 07, 1980	2.7	0.9	2

July 06, 1981	4.2	1.2	2

July 02, 1982	2.2	1.1	2

July 01, 1983	2.45	0.29	2

July 06, 1984	2.49	0.78	2

July 05, 1985	2.56	0.84	2

May 02, 1986	0.7	1.5	2

May 15, 1986	2.5	1.7	2

May 25, 1986	1.9	0.41	2

May 31, 1986	0.6	5.9	2

June 07, 1986	2.26	0.35	2

June 16, 1986	0.5	1.2	2

July 03, 1986	2.34	0.39	2

July 02, 1987	2.17	0.64	2

July 01, 1988	2.8	0.24	2

July 06, 1990	1.46	0.7	2

July 12, 1991	1.16	0.6	2

July 01, 1993	0.99	0.5	2

July 01, 1994	0.58	0.48	0.753

July 07, 1995	0.74	0.44	0.627

July 05, 1996	1.26	0.54	0.6931

July 03, 1997	1.06	0.73	1.058

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX A5

	Data Tables for Hartford, CT

Sr-90 in Milk Results

Hartford, CT

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

April 15, 1960	8	2	2

May 15, 1960	9	2	2

June 15, 1960	10	2	2

July 15, 1960	6	2	2

August 15, 1960	10	2	2

September 15, 1960	9	2	2

October 15, 1960	8	2	2

November 15, 1960	10	2	2

December 15, 1960	8	2	2

January 15, 1961	6	2	2

February 15, 1961	7	2	2

March 15, 1961	8	2	2

April 15, 1961	9	2	2

May 15, 1961	8	2	2

June 15, 1961	10	2	2

July 15, 1961	10	2	2

August 15, 1961	8	2	2

September 15, 1961	7	2	2

October 15, 1961	10	2	2

November 15, 1961	8	2	2

December 15, 1961	7	2	2

January 15, 1962	10	2	2

February 15, 1962	10	2	2

March 15, 1962	7	2	2

April 15, 1962	10	2	2

May 15, 1962	9	2	2

June 15, 1962	14	2	2

July 15, 1962	12	2	2

August 15, 1962	10	2	2

September 15, 1962	13	2	2

October 15, 1962	12	2	2

November 15, 1962	14	2	2

December 15, 1962	7	2	2

January 15, 1963	12	2	2

February 15, 1963	12	2	2

March 15, 1963	12	2	2

April 15, 1963	12	2	2

May 15, 1963	19	2	2

June 15, 1963	36	3.6	2

July 15, 1963	38	3.8	2

August 15, 1963	32	3.2	2

September 15, 1963	24	2.4	2

October 15, 1963	24	2.4	2

November 15, 1963	24	2.4	2

December 15, 1963	26	2.6	2

January 15, 1964	24	2.4	2

February 15, 1964	22	2.2	2

March 15, 1964	24	2.4	2

April 15, 1964	22	2.2	2

May 15, 1964	23	2.3	2

June 15, 1964	23	2.3	2

July 15, 1964	22	2.2	2

August 15, 1964	20	2	2

September 15, 1964	16	2	2

October 15, 1964	14	2	2

November 15, 1964	14	2	2

December 15, 1964	15	2	2

January 15, 1965	16	2	2

February 15, 1965	15	2	2

March 15, 1965	16	2	2

April 15, 1965	16	2	2

May 15, 1965	14	2	2

June 15, 1965	16	2	2

July 15, 1965	15	2	2

August 15, 1965	13	2	2

September 15, 1965	12	2	2

October 15, 1965	13	2	2

November 15, 1965	13	2	2

December 15, 1965	11	2	2

January 15, 1966	11	2	2

February 15, 1966	10	2	2

March 15, 1966	11	2	2

April 15, 1966	12	2	2

May 15, 1966	11	2	2

June 15, 1966	15	2	2

July 15, 1966	11	2	2

August 15, 1966	11	2	2

September 15, 1966	10	2	2

October 15, 1966	11	2	2

November 15, 1966	9	2	2

December 15, 1966	10	2	2

January 15, 1967	10	2	2

February 15, 1967	10	2	2

March 15, 1967	9	2	2

April 15, 1967	9	2	2

May 15, 1967	9	2	2

June 15, 1967	9	2	2

July 15, 1967	11	2	2

August 15, 1967	10	2	2

September 15, 1967	9	2	2

October 15, 1967	8	2	2

November 15, 1967	7	2	2

December 15, 1967	10	2	2

January 15, 1968	11	2	2

February 15, 1968	8	2	2

March 15, 1968	7	2	2

April 15, 1968	10	2	2

May 15, 1968	10	2	2

June 15, 1968	11	2	2

July 15, 1968	14	2	2

August 15, 1968	13	2	2

September 15, 1968	11	2	2

October 15, 1968	4	2	2

November 15, 1968	9	2	2

December 15, 1968	8	2	2

January 15, 1969	8	2	2

February 15, 1969	7	2	2

March 15, 1969	6	2	2

April 15, 1969	8	2	2

May 15, 1969	8	2	2

June 15, 1969	8	2	2

July 15, 1969	8	2	2

August 15, 1969	10	2	2

September 15, 1969	7	2	2

October 15, 1969	6	2	2

November 15, 1969	6	2	2

December 15, 1969	7	2	2

January 15, 1970	10	2	2

February 15, 1970	6	2	2

March 15, 1970	7	2	2

April 15, 1970	7	2	2

May 15, 1970	8	2	2

June 15, 1970	9	2	2

July 15, 1970	8	2	2

October 15, 1970	7	2	2

January 15, 1971	8	2	2

April 15, 1971	6	2	2

July 15, 1971	9	2	2

October 15, 1971	6	2	2

January 15, 1972	6	2	2

April 15, 1972	5	2	2

July 15, 1972	7	2	2

October 15, 1972	4	2	2

January 15, 1973	5	2	2

April 15, 1973	4	2	2

July 15, 1973	4	2	2

July 15, 1974	5	2	2

July 15, 1975	3.1	1	2

July 15, 1976	5.7	1.6	2

October 08, 1976	4.1	0.5	2

October 12, 1976	3.6	0.3	2

October 15, 1976	3.9	0.5	2

October 22, 1976	3.4	0.5	2

October 29, 1976	2.4	0.3	2

December 03, 1976	4	0.6	2

July 15, 1977	5.6	1.5	2

October 03, 1977	4	0.8	2

October 10, 1977	3.3	0.7	2

October 17, 1977	4.7	0.7	2

October 24, 1977	2.6	0.5	2

July 15, 1978	4.8	1.5	2

July 11, 1979	3.1	1	2

July 07, 1980	2.7	0.9	2

July 06, 1981	3.5	1.1	2

July 06, 1982	3.6	1.1	2

July 11, 1983	2.43	0.36	2

July 16, 1984	2.4	1	2

July 08, 1985	2.78	0.86	2

May 05, 1986	1.94	0.7	2

May 15, 1986	0.9	1.5	2

May 25, 1986	1.85	0.89	2

June 02, 1986	1.2	1.1	2

June 06, 1986	2.64	0.7	2

June 16, 1986	2.28	0.51	2

July 01, 1986	1.86	0.47	2

July 06, 1987	2.22	0.69	2

July 11, 1988	2.47	0.9	2

July 02, 1990	1.59	0.86	2

July 06, 1992	2.34	0.61	2

July 08, 1996	0.75	0.72	1.13

July 10, 1997	1.31	0.65	0.9238

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX A6

	Data Tables for Wilmington, DE

Sr-90 in Milk Results

Wilmington, DE

Date (1)	Concentration (pCi/L)	2-Sigma Uncertainty (2) (pCi/L)	Minimum
Detectable Concentration (3) (pCi/L)

June 15, 1960	10	2	2

July 15, 1960	10	2	2

August 15, 1960	7	2	2

September 15, 1960	8	2	2

October 15, 1960	8	2	2

November 15, 1960	8	2	2

December 15, 1960	8	2	2

January 15, 1961	8	2	2

February 15, 1961	6	2	2

March 15, 1961	6	2	2

April 15, 1961	7	2	2

May 15, 1961	12	2	2

June 15, 1961	10	2	2

July 15, 1961	8	2	2

August 15, 1961	12	2	2

September 15, 1961	9	2	2

October 15, 1961	15	2	2

November 15, 1961	8	2	2

December 15, 1961	9	2	2

January 15, 1962	10	2	2

February 15, 1962	11	2	2

March 15, 1962	9	2	2

April 15, 1962	14	2	2

May 15, 1962	14	2	2

June 15, 1962	17	2	2

July 15, 1962	12	2	2

August 15, 1962	12	2	2

September 15, 1962	14	2	2

October 15, 1962	14	2	2

November 15, 1962	16	2	2

December 15, 1962	15	2	2

January 15, 1963	16	2	2

February 15, 1963	18	2	2

March 15, 1963	17	2	2

April 15, 1963	13	2	2

May 15, 1963	31	3.1	2

June 15, 1963	41	4.1	2

July 15, 1963	34	3.4	2

August 15, 1963	28	2.8	2

September 15, 1963	27	2.7	2

October 15, 1963	24	2.4	2

November 15, 1963	24	2.4	2

December 15, 1963	22	2.2	2

January 15, 1964	22	2.2	2

February 15, 1964	19	2	2

March 15, 1964	22	2.2	2

April 15, 1964	28	2.8	2

May 15, 1964	34	3.4	2

June 15, 1964	28	2.8	2

July 15, 1964	23	2.3	2

August 15, 1964	19	2	2

September 15, 1964	18	2	2

October 15, 1964	14	2	2

November 15, 1964	16	2	2

December 15, 1964	17	2	2

January 15, 1965	18	2	2

February 15, 1965	18	2	2

March 15, 1965	20	2	2

April 15, 1965	19	2	2

May 15, 1965	18	2	2

June 15, 1965	21	2.1	2

July 15, 1965	16	2	2

August 15, 1965	15	2	2

September 15, 1965	14	2	2

October 15, 1965	16	2	2

November 15, 1965	13	2	2

December 15, 1965	14	2	2

January 15, 1966	13	2	2

February 15, 1966	13	2	2

March 15, 1966	13	2	2

April 15, 1966	17	2	2

May 15, 1966	17	2	2

June 15, 1966	16	2	2

July 15, 1966	13	2	2

August 15, 1966	12	2	2

September 15, 1966	12	2	2

October 15, 1966	12	2	2

November 15, 1966	11	2	2

December 15, 1966	13	2	2

January 15, 1967	11	2	2

February 15, 1967	11	2	2

March 15, 1967	11	2	2

April 15, 1967	11	2	2

May 15, 1967	13	2	2

June 15, 1967	12	2	2

July 15, 1967	12	2	2

August 15, 1967	10	2	2

September 15, 1967	11	2	2

October 15, 1967	9.8	2	2

November 15, 1967	11	2	2

December 15, 1967	9	2	2

January 15, 1968	13	2	2

February 15, 1968	8	2	2

March 15, 1968	9	2	2

April 15, 1968	11	2	2

May 15, 1968	11	2	2

June 15, 1968	16	2	2

July 15, 1968	12	2	2

August 15, 1968	10	2	2

September 15, 1968	9	2	2

October 15, 1968	6	2	2

November 15, 1968	7	2	2

December 15, 1968	9	2	2

January 15, 1969	9	2	2

February 15, 1969	10	2	2

March 15, 1969	8	2	2

April 15, 1969	9	2	2

May 15, 1969	8	2	2

July 15, 1969	10	2	2

August 15, 1969	11	2	2

September 15, 1969	6	2	2

October 15, 1969	9	2	2

November 15, 1969	7	2	2

December 15, 1969	7	2	2

January 15, 1970	7	2	2

February 15, 1970	7	2	2

March 15, 1970	10	2	2

April 15, 1970	7	2	2

May 15, 1970	8	2	2

June 15, 1970	11	2	2

July 15, 1970	13	2	2

October 15, 1970	8	2	2

January 15, 1971	8	2	2

April 15, 1971	8	2	2

July 15, 1971	10	2	2

October 15, 1971	6	2	2

January 15, 1972	6	2	2

April 15, 1972	8	2	2

July 15, 1972	11	2	2

October 15, 1972	10	2	2

January 15, 1973	4	2	2

April 15, 1973	3	2	2

July 15, 1973	8	2	2

July 15, 1974	5	2	2

July 15, 1975	6.5	1.4	2

July 15, 1976	5.2	1.7	2

October 12, 1976	6.6	1.2	2

October 15, 1976	5.6	0.6	2

October 22, 1976	6.2	1	2

October 29, 1976	5.1	0.6	2

November 15, 1976	3.5	0.6	2

July 15, 1977	5.9	1.6	2

October 03, 1977	4.8	1.1	2

October 17, 1977	7	1.2	2

October 24, 1977	5	1	2

July 15, 1978	5.3	1.3	2

July 02, 1979	3.7	1	2

July 07, 1980	3.1	1.5	2

July 20, 1981	3.59	0.99	2

July 07, 1982	2.4	1.2	2

May 12, 1986	2.19	0.91	2

May 15, 1986	2.52	0.27	2

May 25, 1986	2.9	1.5	2

May 31, 1986	2.3	1.6	2

June 09, 1986	2.1	2.8	2

June 18, 1986	2.91	0.45	2

July 03, 1986	2	1.1	2

July 13, 1987	3.73	0.86	2

July 06, 1988	2.2	1	2

July 19, 1989	2.11	0.93	2

July 11, 1990	1.51	0.78	2

July 13, 1994	1	0.45	0.598

July 20, 1995	0.85	0.59	0.847

July 23, 1996	0.55	0.74	1.203

July 09, 1997	1	0.66	0.9224

Notes:	(1)	For the period 1960 through 1978, sample specific collection
dates were not published for routine samples.  For data presentation
purposes, the individual or the composite sample for that month is
assumed to be “collected” on the 15th of the month.  For non-routine
samples collected during 1976 and 1977 (i.e., increased sampling due to
Chinese atmospheric nuclear weapons tests) and for samples collected
after July 1978, specific collection dates are available and are used.

(2)	The uncertainties were reported in Radiological Health Data and
Reports to be " 2 pCi/L for Sr-90 concentrations less than 20 pCi/L, and
10% of the concentration for Sr-90 concentrations greater than 20 pCi/L.
 Sample specific uncertainties are available for data beginning in
October 1975.

(3)	The Minimum Detectable Concentrations (MDC) were reported in
Radiological Health Data and Reports as either 1 or 2 pCi/L.  The value
of 2 pCi/L is used since it was based upon more data than the 1 pCi/L
value.  This MDC is also used for results reported in Environmental Data
Reports and for values in the National Air and Radiation Environmental
Laboratory’s (NAREL) electronic database where no sample specific MDC
is provided.  When the NAREL’s electronic database provides sample
specific MDC values (beginning in July 1994), those values are reported.

	APPENDIX B

	Graphs for Sr-90 in Milk for Selected Cities