Stream Monitoring for Heavy Metals by Analysis of Aquatic Insect Larvae by Charles M. Weiss Professor of Environmental Biology Richard P. Maas Co-Princi pal Investigator and Steven A. Dressing Research Ass ist ant Department of Envi ronmental Sciences and Engineering School of Public Health The University of North Carol ina a t Chapel Hill Chapel Hill, North Carolina 27514 The work upon which this publication i s based was supported i n part by funds provided by the Office of Water Research and Technology, U. S. Department o f the Interior, Washington, D. C. through the Water Resources Research Institute of the University of North Carolina as authorized by the Water Research and Development Act of 1978. Project No. A-095-NC I Agreement No. 14-34-0001 -8035 ~l I ~I January 1981 ESE No. 602 I ~ I ACKNOWLEDGMENTS Dr. Leonard Smock, while completing his own doctoral research lent invaluable assistance i n the collection, taxonomy and sample preparation of the benthic organisms. The assistance of Mr. Charles T. Paige and Richie Beale i n the determination of anions and cations is gratefully acknowledged as we1 1 as the continuing helpful suggestions of Dr. Mark Shuman with reference to the analysis of heavy metals. Mrs. Donna Simmons patiently and carefully transferred the hand drafts of the manuscript and tables into final typed form. DISC LAIMER STATEMENT Contents of this publication do not necessarily reflect the views and policies of the Office of Water Research and Technology, U. S. Department of the Interior, nor does mention of trade names or commercial products constitute their endorsement or recommendation for use by the U. S. Government. Pb s tract The potential of aquatic insects for monitoring heavy metals i n North Carol i na streams and rivers was i nvesti gated. The caddisfly, Hydropsyche sp. and the midgefly, Chironomus sp., both common i n North Carolina Rivers, were exposed to a wide range of aqueous cadrni um, chromium and zinc concentrations under laboratory and fie1 d conditions. The rates of accumulation and 1o ss of the test metals as well as the equilibrium metal concentrations i n the test species a t a given metal exposure level were determined. The effects of other biol ogical a rid chemical factors i ncl uding water temperature, chemical speciation of the metal s , concentrations of competing metal s, sediment metal concentrations and organism weight on the metal accumulation of the organisms were a1 so evaluated. Chironomus sp. was found to accumulate all three metals to a greater extent than Hydropsyche sp., although a strong linear relationship was noted between aqueous and organi sm metal concentrations over the concentration range used for both organisms. Metal equilibrium between organisms and water was attained with one to three days i n all cases. Equilibrium organism metal concentrations increased with increasing water temperature for a given aqueous metal concentration. The rate of metal release following transfer of exposed organisms to metal free water was significantly slower for Hydropsyche sp. This characteristic would i ndi cate a greater util ity of Hydropsyche sp. for stream metal monitoring. Elevated organism metal concentrations were observed for 3 to 12 days following . exposure depending on organism species and metal exposure level Sediment and organi sm metal concentrations were posi tively correlated, a1 though information was limited by the exclusion of sediments from the laboratory metal exposure systems. Chemical speciation of cadmium was not observed to significantly affect organism metal uptake i n these experiments. The presence of potentially competing metal s were not found to si gni ficanty affect organi sm metal accumulation except i n one case where the presence of a very high concentration of Zn reduced Cd and Cr uptake i n both test species. Organi sm metal concentration was found to decrease with increasing organism weight a t 1o w aqueous metal con.c entrations, however this trend disappeared a t higher metal exposure 1e ve1 s The s trony relati onstiip between water and organism metal concentration and the relatively slow loss of organism bound metal following exposure i ndicate that organism monitoring of heavy metals i n streams should be a time and cost effective method of screening North Carolina streams and river for heavy metal discharges. iii Table o f Contents Page I I .................................................. ACKNOWLEDGEMENTS ii .......................................................... Abstract iii .................................................... List of Tables v i ................................................... Li st o f Fi gures v i i i ........................................... SUMMARY AND CONCLUSIONS x ii ...................................................... INTRODUCTION 1 ............................................ Objectives and Scope 5 ............................................. MATERIALS AND METHODS ............................................... Field Methodology ........................................... Analytical Procedures .................................... Laboratory-Fie1 d Experiments Laboratory Studies on Effects o f Cadmium Speciation on Uptake ............................................. by Hydropsyche sp ............................................ RESULTS AND DISCUSSION ............................................... Field Collections .... Laboratory Exposures t o Metals Fol lowed by Stream Desorption .... Effect of Water Metal Concentration on Oganism Metal Content .......... Effect of Aquatic Insect Species on Metal Accumulation ............ Effect of Water Temperature on Organism Metal Uptake ............. Effect of Competing Metals on Organism Metal Uptake . Effect of Substrate Metal Concentration on Organism Metal Uptake ....... Effect of Organism Weight on Organism Metal Concentration ............. Effect of Metal Speciation on Organism Metal Uptake ....................................... Kinetics o f Metal Release ....... A Model Re1 atin g Organism and Stream Metal Concentrations ......................................... Field Test o f the Model ........................................................ REFERENCES . .. . . . . . . . . . . . . . . .. . .. . .. . . . . .. . .. . . . . . . .. .. . . . . . . . . . . . APPENDICES 1. Daily Total and Filtered Cadmium Concentrationsat Stations No. 6, No. 7, No. 10-Up, No. 10-Down, January 12 t o ................................O.,........ February 10, 1978 2. Daily Total and Fi 1t ered Chromium Concentrations at Stations No. 6, No. 7, No. 1.0 .-.U.p., ..a.n.d. .N.o.. ..1.0.-D..ow..n,. ..J.a.n.u. .a.r y. .1.2.. t.o .. ..... February 10, 1978 3. Daily Total and Filtered Zinc Concentration a t Stations No. 6, No. 7, No. 1.0.-.U.p.,. .N..o.. .1.0.-.D.o.w.n., ..J.a..n.u.a.r.y. .1.2. t..o. ......... February 10, 1978 4. Weight Normalized Organism Metal Concentration (vglg) from.. . . Dai l y Fie1d Collections and Laboratory Aquari a Exposures . .. . . . 5. Cadmium, Chromium and Zinc (vg/g) of Stream Substrates .. .. ., .. . . . 6. Total and Dissolved Metals (vgll) of Stream Water ............................. 7. Stream Water Quality Parameters 8. muaria W..a.te.r. .W..a..l.it.y. .P..a.ra.m..e.t.e.rs.,. .M.e.a.n. .V..a.lu.e.s. .D..u.r.in.g. .E.x.p.o.s.u.r.e. Periods List of Tables Page + 1 Measured Aquaria Metal Concentrations for H dro s che sp. . Laboratory Experiments Water From Eno River and organ Creek. 13 2 Measured Exposure Aquaria Metal Concentrations for Chironomus sp .Laborato.r.y. .E..x.p.o.su..re. .E..x.p.e.r.im..e.n.ts.,. .W..a.te.r. .F.r.o.m. .E.l. 1.e .r.b.e.e. .C.r.e.e.k. .. 14 Station 6 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Composition of Media in Aquaria 19 4 Cadmium Concentrations i n Total Water and Filtered Water (ug/l ) and Benthic. .M..a.c.r.o.i.n.v.e.r.t.e.b.r.a.te.s. .(.u.g../g.). .S.e.p.t.e.m.b..e.r .1.9.7.7. .t.o. ........ June 1978 21 5 Cadmium in Water and Benthi c M.a.c.r.o.i.n.v.e.r.t.e.b.r.a.te.s. .S.t.a.t.i.o.n. .6.,. ..... May23, 1978toJune20, 1978 24 6 Cadmium i n Water and Benthic M.a .c. r. o. i. n. v. e. r. t. e. b. r. a. te. s. . S. t. a. t. i. o. n. . 7. ,. . . . . . May 23, 1978 t o June 20, 1978 25 7 Estimation of the C.ad.m..iu.m. .V..a.r.ia.n.c.e. .f.o.r. .W..a.te.r. .a.n.d. .B..e.n.th.i.c. ....... Macroinvertebrates 26 8 Chromium Concentrations in Water an.d . . B. .e . n.t h. o. s. ,. . S. e. p. t. e. m. b. e. r. .1 .9. 7. 7. . . . to June 1978, A1 1 Sample Stations 30 9 Chromium Concentrations i n W.a.t.e.r .a.n.d. .C..h.ir.o.n.o.m.u.s. .s.p... .M.a.y. .2.3.,. .1.9.7.8 toJune20, 1978, Station6 33 10 Chromium Concentrations i n Water, Stenonema rubrum, 8E h-eme7rel-la, and Hydropsyche sp., May 23, 1978 t o June 2 0 m , tation 34 11 Estimation of C..hr.o.m.i.u.m. .V..a.ri.a.n.c.e. .f.o.r. .W..a.te.r. .a.n.d. .B.e.n.t.h.i.c .M..a.c.ro.-. .... invertebrates 35 12 Zinc Concentrations i n Water (ug/1) and .B. .e n t.h. o. s. . (. u. g ./g ).,. . A ll Stations, September 1977 t o June 1978 39 13 Zinc Concentrations i n Water (u.g ../ l.). . a. n. d. . B. e.n. t. h. o. s. . (. u. g. ./ g. )., . . S. t. a. t. i. o. n. 6 May 23, 1978 t o June 20, 1978 42 14 Zinc Concentrations i n Water (p..g./.l.) .a.n.d. .B..e.n.th.o.s. .(.p.g../g.).,. .S.t.a.t. i.o.n. 7 May23, 1978to June 20, 1978 43 15 Estimation of t.h.e.. Z..in.c. .V..a.r.ia.n.c.e. .f.o..r .W..a.te.r. .a.n.d. .B..e.n.th.i.c. .M..a.cr.o.-. ... invertebrates 4 5 Table 16 Relationship (corr. coef., r2) of Metal Concentrations in Hydropsyche sp. and Chironomus sp. to- M etal Co.n.c.e.n.t.r.a.ti.o.n. .i.n.. Water i n a Temperature Range of 22.7 24.g°C 67 17 Mean Values of Metal Concentrations i n Organisms, Water and Substrate, Morgan- Creek and Eno River. .S.a.m..p.l.e.s., ................. August 1 5, 1979 September 4, 1979 74 18 Correlation of Metal Concentrations i n Organis.m.s. .w.i. t.h.. M..e.ta.l. .... Concentration i n Stream Water and Substrates 82 19 Metal Concentrations fo.r. R..ep.1. i.c.a..te.. C.h.i. r.o.n.o.m..us. .s.p... .S.a.m..p.l.es. .o.f. ... DifferentMeanWeights 84 20 Metal Concentrations fo.r. R..e.p.l.i.c.a.te. .H..y.d.ro.p.s.y.c.h.e. .s.p... .S.a.m..p.le.s. .o.f. .. Different Mean Weights 8 5 21 Mean Values and 95% Confidence Interval of Cadmium i n %dro s che s p. an.d. .T..o.ta.l. .a.n.d. .F..re.e. .C..ad.m..iu.m. .i.n.. W..a.t.er. .o.f. ......... xposure quaria 90 22 Chemical Speciation of Ca, Cd, Cr. .a.n.d. .Z.n. .i. n. .S.t.r.e.a.m. .a.n.d. .A..q.u.a.r.ia. . Water Samples by Use of REDEQL2 94 23 Detection Intervals and Metal Release Rate Constants for Meta.l. . Desorbed from Hydropsyche sp. and Chironomus sp. i n Streams 97 24 Mean, Standard Deviation and 95% Confidence Interval of Organism Metal Concen.t.r.a.ti.o.n. .f.o..r .a. .G..iv.e.n. .M..e.ta.l. .C..o.n.c.e.n.t.ra..ti.o.n. .a.n.d. ........ Temperature 101 25 Correlation Coefficients for All Experiments, Dissolved Metal and Organism Metal .C..o.n.c.e.n.tr.a.t.io.n. ,.. T.o.t.a.l .M..e.ta.l. .a.n.d. .O.r.g.an.i. sm. ..M.e.t.a.l ... Concentration 104 26 Intercepts, Slopes, Correlatio.n. .C..o.e.f.f.i.c.ie.n..ts. .a.n.d. .S.i.g.i.n.i.f.i.c.a.n.c.e. . Level s of Statistical Models 106 27 Water Quality Parameters from Model Testing E..x.p.e.ri.m..e.n.t .F.o.u..rt.h. .. Creek, October 23, 1980 to October 30, 1980 108 + 28 Metal Concentrations i n wdro syche sp. and Substrate as Co-l lected i n Model Testing E..x.p.e.ri.m..en..t ..o.u.r.t.h. .C.r.e.e.k.,. .O.c.t.o.b.e.r. .2.3,. .1.9.8.0. ..... October 30, 1980 109 29 Predicted versus Observed Hydropsyche sp. and Fourth Creek 24-hour Com.p.o.s.i.te. .C.d. .a.n.d. .C.r. .C..o.n.c.e.n.t.r.a.t.io.n..s .f.r.o.m. .M..o.d.el. .T..e.s.ti.n.g.. . Experiment 110