April 11, 1979 QUALITY OF WATER TECHNICAL MEMORANDUM NO. 79.12 Subject: PROGRAMS AND PLANS--Questionable analytical values for lead and cadmium This is to notify you that lead and cadmium concentrations reported for samples collected during the period April 1978 to February 1979 are questionable because of a contamination problem with the nitric acid ampoules supplied by the Central Laboratories. For quite some time, nitric acid ampoules distributed to field and project offices for preservation of water samples for trace metal analysis have been purchased from a single, apparently reliable supplier. It is now known that during the specified period an unknown number of the ampoules received by the labs and redistributed to field and project offices were contaminated with lead, and to a much lesser extent, with cadmium. The necks of these ampoules contained a ring of blue paint that was extremely high in lead content and it is believed that at least some of the contamination problem may have originated with this blue paint. The extent of the contamination was sporadic in nature and varied greatly from ampoule to ampoule. A shipment of 100 boxes of l-mL ampoules (total shipment = 10,000 ampoules) that was received from the supplier in November 1978 was subsampled by the Atlanta Central Laboratory. Two ampoules from each box were selected at random and the acid from each was added to 250 mL of demineralized water. These acidified water samples were analyzed using the standard chelation- extraction procedure (method no. I-1400) for lead. The results were distributed into the following concentration ranges: Resulting lead concentration Lead per Percentage of if acid from one ampoule were ampoule lead concentrations in added to a water sample of the (micrograms) range indicated size; mq/L 250 ml 500 ml 1 liter 0.00-1.25 17 0-5 0-2 0-l 1.50-2.50 23 6-10 3-5 2-3 2.75-5.00 l9 11-20 6-10 3-5 5.25-12.50 29 21-50 11-25 6-12 12.75-25.00 6 51-100 26-50 13-25 25.25 -250 2 l0l-l000 51-500 26-250 >250 3 >l000 >500 >250 If desired, the following SAS procedures can be executed to obtain a graphical presentation of the distribution of the lead and cadmium data and to print out a subset of the data for which values exceed a specified concentration limit. These procedures must be executed following the procedure given above. (See WATSTORE Users Guide, Volume 3, Chapter IV, Section R, for additional information). //EXEC WRDSAS (TIME SHOULD EQUAL TIME GIVEN ON EXEC QWRETR card) //SYSIN DD* PROC QWSAS SNAME YEAR MONTH DAY TIME DECTIME; PROC CHART; HBAR P01025 P01026 P01027 P01049 P01050 P01051 / LEVELS=25; TITLE DATA FOR ALL STATIONS; (This procedure will produce histograms for each parameter. The histograms will include the data from all stations retrieved.) PROC PLOT; PLOT P01025*DECTIME='*'; PLOT P01026*DECTIME='*' PLOT P01027*DECTIME='*'; PLOT P01049*DECTIME='*'; PLOT P01050*DECTIME='*'; PLOT 01051*DECTIME='*' (The above procedure will produce graphs of concentration vs time for each parameter for all stations retrieved. Six graphs will be produced.) DATA; SET; IF P01025 >m or P01026 >m or P01027 >p or P01049 >n or P01050 >s or P01051 >t; (where m, n, p, r, s, and t are your specified limits in ug.L) PROC PRINT; VARIABLES STATION SNAME YEAR MONTH DAY TIME P01025 P01026 P01027 P01049 P01050 P01051; TITLE ANALYSES WITH VALUES EXCEEDING SPECIFIED LIMITS; /* (the above procedure will produce a table containing analyses which exceed limits specified by the requestor.) As can be seen, the contamination problem was severe, with nearly 60 percent of the ampoules containing more than 2.5 ug of lead. This amount of lead would result in an increase in lead concentration of 5 ug/L in a 500 milliliter water sample. Many of these ampoules were also analyzed for cadmium. The contamination was less severe, with the cadmium concentration running approximately 10 percent of the lead contamination concentration. It is imperative that all field and project offices dispose of any nitric acid ampoules with a blue ring that may still be in their possession. All nitric acid ampoules distributed by the central laboratories since December 1, 1978 have lacked the painted blue ring. Random analyses of acid ampoules purchased since December have shown them to be free of lead and cadmium contamination. A quality-control program involving regular analysis of each shipment of acid ampoules has been instituted and should insure that this problem will not be repeated in the future. All lead and cadmium determinations made during the period April 1978 to Fehruary 1979 should be considered suspect unless it is certain that the acid ampoules in question were not used to acidify the samples. We recommend that field and project office personnel carefully examine all lead and cadmium data collected during the above period. About the only way this can be done is to retrieve the data from the WATSTORE water quality file and compare lead and cadmium data from the period in question with prior data for that site or river reach. Lead and cadmium values for the period April 1978-February 1979 which appear suspect should be deleted from district or project files and from the WATSTORE Water Quality File unless field personnel have other knowledge that indicates the values are correct. If either the dissolved or total recoverable value for lead is deleted, then the corresponding dissolved or total recoverable value for cadmium should be considered suspect and should be deleted also unless the value is "zero." Also, if either the dissolved or total recoverable value for lead or cadmium is deleted then the suspended recoverable value must be deleted. The following procedure will facilitate the retrieval of the data in question from the water quality file. Refer to the WATSTORE Users Guide, Volume 3, Chapters 3 and 4, for additional information. //JOB CARD /*PROCLIB CARD // EXEC QWRETR (increase TIME and REGION if necessary) //SYSIN DD * Ml 197710197903S XA534 22 XQWSAS (Optional, use only if SAS procedures are desired) 0TIMES010250102G01027010490105001051 L XX (Where XX is district code, Columns 12-13) S (one or more station range cards) /* // EXEC QWTABLES (increase TIME and REGION if necessary) /* We deeply regret the problems and inconvenience that the contaminated acid ampoules have caused. For what it is worth, the Survey was not the only Federal agency adversely affected by this quality assurance problem of the supplier of the ampoules. As stated previously, the necessary quality control steps have been taken to prevent a recurrence of this situation. R. J. Pickering WRD Distribution: A, B, S, FO, PO