WATER QUALITY--Sampling:  Pesticides

                                                 June 19, 1975


Subject:  WATER QUALITY--Sampling:  Pesticides

Enclosed for your information is a copy of "Guidelines on Sampling
and Statistical Methodologies for Ambient Pesticide Monitoring,"
which was compiled by the Monitoring Panel of the Federal Working
Group on Pest Management. Input from the Geological Survey to the
compilation of these guidelines, particularly to the section on 
the Hydrologic Environment, was provided by Herman Feltz, our 
representative on the Monitoring Panel. Although these guidelines 
are generally consistent with the Division's procedures for 
sampling and analysis of pesticides in the hydrologic environment, 
as defined in recent instructional memoranda and in the Survey's 
TWRI on analysis of organic substances, there are some differences 
due to the general nature of the guidelines.

In the past, samples collected by Division personnel as part of 
the National Pesticide Water Monitoring Program have not been 
shipped in a chilled condition as called for in the guidelines (p. 
IV-8).  This was due in part to the lack of suitable containers 
for shipping glass bottles in an iced condition without breakage, 
and in part to the persistent nature of the pesticides that we 
were monitoring initially.  The Operations Section currently is 
working on a design for a container in which we can safely ship 
the iced bottles. Until an acceptable container is developed, we 
recommend that the bottles be kept chilled before and after 
shipping on the premise that the persistent pesticides for which 
we are analyzing will not seriously degrade by being raised to 
ambient temperature during the few days required for shipment. We 
further recommend immediate extraction and chilling of the 
extracts when the samples arrive at the laboratory.

Section III of the guidelines calls for freezing of soil samples.
Plans are being completed for additional research by Division 
personnel on the advantages and disadvantages of preservation of 
water samples by freezing. At the present time, we do not 
recommend that water or sediment samples be frozen.

I hope you will find the guidelines useful in field operations. 
Please route them to personnel under your supervision as 
appropriate. Questions concerning the guidelines should be 
addressed to the Chief, Quality of Water Branch.

                             R. J. Pickering 
                             Chief, Quality of Water Branch


WRD Distribution: A,B,FO-LS,PO