Occurrence and Distribution of Bacterial Indicators and

Transcription

1 PPLED ND ENVRONMENTL MCROBOLOGY, ug. 1977, p Copyright C 1977 mericn Society for Microbiology Vol. 34, No. 2 Printed in U.S.. Occurrence nd Distribution of Bcteril ndictors nd Pthogens in Cnl Communities long the Texs Cost SGR M. GOYL, CHRLES P. GERB, ND JOSEPH L. MELNCK* Deprtment of Virology nd Epidemiology, Bylor College of Medicine, Houston, Texs 773 Received for publiction 18 Februry 1977 ncresed construction of residentil cnl communities long the southern costline of the United Sttes hs led to concern bout their impct on wter qulity. Pollution of such ded-end cnls is potentilly hzrdous becuse of their hevy usge for recretionl ctivities. Coliforms, fecl coliforms, nd slmonelle in the surfce wter nd bottom sediments of six selected residentil costl cnls were monitored over period of 17 months. No sttisticlly significnt reltionship ws observed between the orgnism concentrtions nd temperture, ph, turbidity, nd suspended solids content of wter. n inverse reltionship between the concentrtion of indictor orgnism nd slinity of wter ws found, however, to occur t 99.9o level of significnce. ll of the microorgnisms studied were found to be present in greter numbers in sediments thn in the overlying wter, often by fctor of severl logs. Hevy rinfll resulted in lrge increses in the number of orgnisms in both wter nd sediment smples. Our results indicte tht bottom sediments in the shllow cnl systems cn ct s reservoirs of enteric bcteri, which my be resuspended in response to vrious environmentl fctors nd recretionl ctivities. n increse in the construction of residentil cnl communities long the Est nd Gulf costs of the United Sttes hs led to concern bout the impct of such mn-mde cnls on the environment. Pollution of such ded-end cnls is potentilly hzrdous becuse of their hevy usge for recretionl ctivities. There re more thn cnl communities long the Texs Gulf cost, the mjority of which re locted in Glveston County. Residentil cnls of six communities utilizing vriety of wste disposl methods were studied to determine their effect on bcteriologicl wter qulity within the cnls. The communities re designed so tht ech home hs cnl frontge, which llows owners to hve direct wter ccess for their bots, s well s for other recretionl ctivities. The result is mze of interconnecting cnls (Fig. 1) tht eventully led into by or other lrge bodies of wter. Mny of the communities, especilly long the Texs cost, re designed primrily for resort purposes nd re occupied only on weekends nd during the summer, but others re designed s permnent fmily residences. The growth of these communities hs been rpid nd lrgely unregulted, nd their effect on wter qulity hs yet to be thoroughly scertined. Pollution of such cnl systems is especilly undesirble becuse of their hevy usge for such recretionl ctivities s bthing, boting, skiing, fishing, nd skin nd scub diving. MTERLS ND METHODS Smpling sites. The cnl communities studied border Glveston By (Fig. 2). These communities were built upon mrsh lnd tht ws filled, in lrge prt, from mteril dredged in the sme re to form network of cnls tht llow residents ccess to the by. digrm of the network of one of these cnls is shown in Fig. 1. The mjority of the homes re occupied during the entire summer months but only on weekends during the rest of the yer. Severl of the communities utilize septic tnks for the tretment of household wstes, wheres others depend upon smll, pckged sewge tretment plnts tht dischrge unchlorinted wstes. The ge, depth, nd type of wste disposl system for ech of the communities studied re summrized in Tble 1. ll smples were collected from the shores of representtive cnls within ech community. Smples. Surfce wter smples were collected in sterile, wide-mouth, screw-cpped bottles. Sediment smples were obtined with the help of n Ekmn dredge nd were plced in individul plstic bgs. The smples were stored on ice for trnsport to the lbortory. n ll cses, the elpsed time between smpling nd nlysis never exceeded h. nlysis of coliforms. Lctose nd EC broth (Difco Lbortories, Detroit, Mich.) were employed to determine the most probble number (MPN) per 1 ml of coliforms nd fecl coliforms, respectively, using five-tube multiple-dilution technique (1). Cold.3 mm phosphte buffer ws used to mke 139 Downloded from on Jnury 13, 219 by guest

2 14 GOYL, GERB, ND MELNCK dilutions. Sediment smples were initilly diluted 1:1 with sterile, buffered wter, nd 2, 2, or.2 ml of this diluted mixture ws inoculted in the pproprite medium to give finl figure of 1, 1, or.1 ml of sediment, respectively. Double-strength broths were used when smple volume inoculted ws equl to or more thn 1 ml. soltion nd enumertion of slmonelle. Slmonelle were detected by three-tube multipledilution technique. pproprite mounts or dilutions of the smple were inoculted, for enrichment, into three replicte tubes of tetrthionte broth contining 1:1, brillint green. fter incubtion t 41. C (28) for 48 h, loopfuls from ech tube were streked on pltes of brillint green gr contining.8 g of sulfdizine per liter. fter incubting t 37 C for 24 h, two suspect colonies from ech plte were inoculted into triple sugr iron (TS) gr slnts nd further incubted for 24 h t 37 C. Strins exhibiting chrcteristic rection on TS gr were purified nd subjected to slide gglutintion test with slmonell poly "O" ntiserum (Difco) nd with group ser. soltes exhibiting gglutintion were considered to be slmonelle. Other prmeters. Slinity nd turbidity of wter smples were determined by using T/C refrctometer (O nstruments Corp., Bufflo, N.Y.) nd turbidimeter (model 21, Hch Chemicl Co., mes, ow), respectively. Temperture nd ph of the wter were recorded concurrently with sm- FG. 1. Cnl system of site 323. TBLE 1. PPL. ENVRON. MCROBOL. pling. The concentrtion of suspended solids ws determined by filtering three 1-ml portions through desiccted, preweighed fiberglss filters (Whtmn, grde GF/C). The filters were rinsed with distilled wter to remove slts, desiccted for 48 h, nd reweighed. The difference ws reported s milligrms of suspended solids per liter of wter. Sttisticl nlysis. Product-moment correltion coefficients were clculted on DEC1 computer using n SPSS sttisticl pckge. Significnce sttistics were clculted for ech of the coefficients. RESULTS ND DSCUSSON MPN of indictor orgnisms. The MPNs of totl nd fecl coliforms of the communities G GULF OF MEXCO FG. 2. Loctions of cnl community smpling sttions. Chrcteristics of cnl communities studied Sttion no. ge (yrs) Depthb (feet) Disposl system H ( ) Collection system nd tretment plnt H ( ) Collection system nd tretment plnt K (3.7) Collection system nd tretment plnt ( ) Septic tnk; lter chnged to collection system nd tretment plnt 323 nd ( ) 2% septic tnk; 7% collection system nd tretment plnt Period for which the cnl hs been in opertion. b Rnge of depth of the wter column in the cnl. Depth in meters is shown in prentheses. Downloded from on Jnury 13, 219 by guest

3 VOL. 34, 1977 under study were determined over 17-month period. The popultion of totl coliforms in the wter column ws found to vry between nd 3,, nd tht of fecl coliforms ws between 2 nd 24,. The concentrtions of totl nd fecl coliforms in sediments, however, vried between 94 nd 2,4, nd between 2 nd 92,, respectively. Coliform counts t sites H81, H82, nd K27 (hereinfter termed s the most polluted sites) were considerbly higher thn those t the other three sites. This my be due to the fct tht the communities locted on these highly polluted cnls hd collection systems tht dischrged the wter directly into the cnls, wheres the other three hd mostly septic tnks. ccording to Gonchriuk et l. (13), home septic tnk systems re potentilly very effective in removing pthogens if operted within their design cpcities. Our results indicte tht they were effective even considering the high wter tble in the res studied. However, generliztions should probbly not be mde since soil conditions nd proximity of the septic tnks to the cnls would influence the occurrence of fecl bcteri within the cnls. Totl coliform levels were lwys higher thn fecl coliform levels, which is not surprising since totl coliforms cn originte from nonfecl sources such s plnts nd soils (9). n generl, the number of indictor orgnisms t ll of the smpling sites ws lower for wter thn for sediment smples. lso, there ws comprtively less fluctution in the bcteril concentrtion in sediment thn in wter smples. ccording to Greenberg (1), dsorption nd sedimenttion tend to remove orgnisms from suspension nd concentrte them in bottom deposits, where they continue n ctive existence. Rittenberg et l. (21) found high coliform levels in mud extending severl miles from mrine sewge outflls dischrging primry effluent, suggesting tht survivl of bcteri ws incresed fter sedimenttion. Vn Donsel nd Geldreich (29) exmined wide vriety of sediments from bthing beches, recretionl lkes, rivers, nd creeks nd found tht totl coliform, fecl coliform, nd fecl streptococci concentrtions were 1 to 1, times higher in sediments thn in the overlying wter. The presence of lrge numbers of orgnisms in bottom sediments s compred to tht BCTERL PTHOGENS N CNL COMMUNTES 141 in wter is prticulrly hzrdous in light of the observtion by Grimes (16) tht incresed fecl coliform counts in wter followed disturbnce nd reloction of bottom sediments by dredging. He further stted tht mintennce dredging of bottom sediments hevily contminted with enteric pthogens could produce temporry helth hzrd in downstrem recretionl res. The observtion by Geldreich (8) tht pthogens cn survive in the bottom deposits of river or lke for severl weeks before they die lso supports the bove theory. The bility of enterobcteri to utilize nutrients relesed from sediments hs been shown (17, 19). Gerb nd McLeod (1) concluded on the bsis of lbortory results tht Escherichi coli could survive nd even grow for periods of time in unsterile nturl sewter when sediment obtined from the cnls observed in this study ws present. Studies by Gerb nd Schiberger (12) indicted tht viruses become redily dsorbed to prticulte mtter involved in sediment formtion, which my prolong their survivl time. Pthogens dsorbed to cnl bottoms pose little dnger to public helth, but resuspension of sediments in response to currents, storms, bot trffic, dredging, nd chnges in slinity nd orgnic mtter (3, 12, 16, 3) cn result in relese of dsorbed bcteri or viruses into the overlying wter, thus posing hzrd to humn helth. n contrst to our studies Syler et l. (24) found lower numbers of indictor orgnisms in sediment thn in wter smples from five loctions on the upper Chespeke By. These sttions were locted in wter rnging from 6 to 8. m in depth nd often severl kilometers from the nerest shore. The shllowness of the cnls we studied nd the limited flushing ction probbly id in the build-up of nutrients within the cnls, llowing more fvorble conditions for their persistence in sediments thn in open by res long cost. Sesonl occurrence of indictor orgnisms t the six sites is shown in Fig. 3 nd 4. The number of orgnisms ws usully higher in winter months thn in the summer. This is bit unusul becuse one would expect the number to be higher in summer when there is hevy usge of the cnls. However, our dt re in ccord with those of Syler et l. (24) nd Fust et l. (), who found higher coliform levels during t1e winter months in open by wters. Fust et l. () found tht fecl coliform survivl in esturine wter ws strongly influenced by temperture, with die-off incresing rpidly with elevted tempertures. Thus, even though the mount of wste being dischrged during the summer my hve been greter, fecl coliform numbers were less becuse of their rpid die-off. Shrp peks were observed in the number of totl coliforms in wter nd sediment smples t the three most polluted sites in June, No- Downloded from on Jnury 13, 219 by guest

4 142 GOYL, GERB, ND MELNCK PPL. ENVRON. MCROBOL. 7 STE: K-27 6i STE: H C -4- Z2-7 STE: H : E Totl Coliforms n Wter / Sediment *Fecl Coliforms n Wter MFecl Coliforms n Sediment Downloded from D F M M J J S O N D J F M MONTHS FG. 3. Comprison of monthly distribution oftotl nd fecl coliforms in wter nd sediment from hevily polluted sites. vember, nd Jnury. These peks were lwys ssocited with rinfll within 48 h of smpling. The peks in the number of totl coliforms were not lwys ssocited, however, with peks in fecl coliforms, which indictes tht most of the totl coliforms fter rinfll were from surfce runoff. n increse in the number of coliforms fter rinfll hs lso been reported by Fechem (6) nd Gerb nd Schiberger (11). Spordic increses in the MPN of bcteri were observed t some of the sttions nd could not be ssocited with rinfll. This sme sitution ws encountered by Fechem (6), who found peks of fecl coliforms during or immeditely fter storm nd t other times due to unexplined fctors. No cler-cut reltionship ws observed between rinfll nd the level of fecl coliforms, which is in ccord with the dt of Fechem (6). Similrly, Gry (14) observed peks of E. coli ssocited with rinfll during the previous 12 h on three occsions, but decrese on two occsions. pek in the number of fecl coliforms in sediment did not lwys correspond to pek in the wter column; i.e., pek offecl coliforms ws observed more often in the wter column thn in the sediment. Tble 2 shows the mens, minim, mxim, nd stndrd devitions of totl coliforms nd fecl coliforms t the six sttions under study. Both groups of orgnisms were found in higher numbers in the sediment thn in the wter column t ll of the sttions nd on ll occsions. Totl coliforms in the sediment smples were 3 to 4,783 times higher thn in the wter smples (medin = 143), wheres this rtio for fecl coliforms ws 1 to 383 (medin = 1). s expected, the fecl coliform concentrtions were less thn third of the totl coliform concentrtions; the fecl coliform counts in the on Jnury 13, 219 by guest

5 VOL. 34, 1977 BCTERL PTHOGENS N CNL COMMUNTES S TE: 324 i ;lucl;l;~~~~~~~~.dtotl Coliforms n Wter / Sediment E - of C: S TE: 323 ~ : STE: 318 1,111.~~~~~~~~~L r1ul D F M M J J S O N D J F M MONTHS EFecl Coliforms n Wter OFecl Coliforms n Sediment FG. 4. Comprison of monthly distribution of totl nd fecl coliforms in wter nd sediment smples from lightly polluted sites. TBLE 2. Mens, minim, mxim, nd stndrd devitions of indictor orgnisms isolted from six sites Totl coliforms (MPN/1 ml) Fecl coliforms (MPN/1 ml) Totl coliform/fecl Sttion no. Mini- Stndrd Mini- Stndrd coliform Men Mximum Stndrd Men Mximum devi- rtio mum devition mumtin tion (e) (men) Surfce wter H81 6, , 1,88 2, , 4,846 8 H82, , 1,68 1, , 4,223 1 K27 1,91 3 3, 12,124 2, , 6, Bottom sediment H81 382,143 3, 1,6, 62,4 9, , 1, H82 192,87 16, 4, 242,119 16, , 3,731 1 K27 77,71 26, -2,4, 861,447 7, , 12, , , 13, , , 11, , ,229 1,7 46, 1, Mens were clculted ssuming tht the 2 nd < counts were equl to the counts reported. Downloded from on Jnury 13, 219 by guest

6 144 GOYL, GERB, ND MELNCK sediment smples were higher thn the wter counts but not s high s the totl coliform counts. sttisticlly significnt correltion ws observed between the log MPN of totl coliforms nd the log MPN of fecl coliforms in wter (Fig. ). lest-squre regression nlysis gve the reltionship: log totl coliforms (MPN/1 ml) =.96 [log fecl coliforms (MPN/ 1 ml)] +.87X. The correltion coefficient (r) for this reltionship ws.847, significnt t 99.9% probbility level. significnt reltionship ws lso found to exist between totl coliform nd fecl coliform concentrtions in sediment when dt from ll the sites were subjected to lest-squre regression nlysis, which gve the reltionship: log totl coliforms (MPN/1 ml) = 3.2 [log fecl coliforms (MPN/1 ml)] +.3X (Fig. 6). The correltion coefficient (r) for this reltionship ws.717, which ws lso significnt t 99.9% level of probbility. The mens of totl coliform/fecl coliform rtios in wter were between 6 nd 4, wheres they were between 1 nd 2,88 for sediment smples. This indictes tht lrge proportion 'U 9._ 1 6 m te U 2 l o o s of bcteri in the sediment smples were totl coliforms (which represent both humn nd nonhumn sources) rther thn fecl coliforms. This is lso supported by the dt of Crney et l. (4), who reported tht fecl contmintion ws more often responsible for coliforms in the wter column thn in the sediment. Other prmeters. The physicl nd chemicl chrcteristics of wter smples from the six sttions re shown in Tble 3. The dt revel tht slinity of the wter ws consistently low t the sites with the highest coliform counts. The lowest tempertures (9 to 12 C) occurred in Jnury nd the highest (31 C) occurred in September. The chnges in the turbidity, slinity, suspended solids, nd ph vlues do not, however, fll into redily discernible pttern. Neither is there ny correltion between these prmeters nd coliform counts, except slinity. Product-moment correltion coefficients were computed between bcteril concentrtions nd other physicochemicl prmeters of the wter smples from the six sites (Tble 4). Totl nd fecl coliforms in wter nd sediment smples E o SiteH81 H82 S S S K27 o o o 318 *m * PPL. ENVRON. MCROBOL. o Downloded from on Jnury 13, 219 by guest Fecl Coliforms Log MPN 1ml 1 FG.. Correltion nlysis of totl nd fecl coliforms in surfce wter.

7 VOL. 34, 1977 BCTERL PTHOGENS N CNL COMMUNTES C '- 2 - E'4 C-.).. o * o Site H81 H82* * K * * U Fecl Coliforms Log MPN 1ml-1 FG. 6. Correltion nlysis of totl nd fecl coliforms in bottom sediments. TBLE 3. Physicochemicl chrcteristics of wter smples tken t six sites Sttion Turbidity (NTU)- Slinity (gkg) Suspended solids ph Temp ( C) no. vg Rnge vg Rnge vg Rnge vg Rnge vg Rnge H H K Between 9 nd 14 mesurements were tken t ech sttion. NTU, Nphelometric turbidity units. were strongly correlted to ech other t 99.9% level of probbility. strong negtive correltion ws observed between totl coliforms nd slinity. With decresing slinity, there ws corresponding increse in the vlue of totl nd fecl coliforms, both in wter nd sediment smples. This reltionship hs lso been demonstrted by Roper nd Mrshll (22), who showed tht E. coli remined firmly dsorbed to sline sediments but ws rpidly desorbed fter dilution of the electrolyte below criticl concentrtion. n inverse correltion between survivl ofe. coli nd slinity of wter hs been demonstrted previously by Fust et l. (). The observed increse in the number of orgnisms my be due prtly to desorption of bcteri fter dilution s result of hevy rinfll. Such effects would not be observed in deeper wter or in res of sprse rinfll, becuse dilution of the sewter would not be s gret. This could explin why n increse in turbidity did not correlte with n increse in Downloded from on Jnury 13, 219 by guest

8 146 GOYL, GERB, ND MELNCK TBLE 4. Product-moment correltion coefficients of ll mesured prmeters Sus- Prmeter Temp ph Turbidity Slinity pended TCW TCS FCW FCS SL/W SL/S solids Temp " ph b Turbidity Slinity b -.963b -.631b b Suspended solids TCW b.847b.7732b TCS b.7169b FCW b FCS b SL/W SL/S 1. TCW, TCS, FCW, FCS, Log MPN (per 1 ml) oftotl coliforms in wter, totl coliforms in sediments, fecl coliforms in wter, nd fecl coliforms in sediments, respectively. SL/W nd SL/S, MPN (per 1 ml) of slmonelle in wter nd sediment, respectively. b Significnt t 99.9% level of probbility. the number of fecl orgnisms in the wter column, s hd been observed by Syler et l. (24). Deeper wter would require the ctul suspension of sediment mteril to cuse concurrent increse in the number of orgnisms in the wter column, wheres, in shllower wter, sediment-ssocited bcteri could lso be resuspended by decrese in slinity. The impct of sediment-ssocited bcteri on the qulity of the overlying wter is in gret prt relted to the depth of the wter. n deep, open by wters the volume of wter bove the sediment would be such tht, if the orgnisms were entirely resuspended, their impct on the totl number of fecl orgnisms in the wter column would be negligible. However, in shllow, mnmde cnls they could hve mrked effect on the totl number of orgnisms in suspension. Considering the re of sediment mteril smpled in reltionship to the volume of overlying wter, s much s 1% increse in the number of orgnisms in the wter column would occur in the shllower cnls if the orgnisms in the sediment were resuspended. t is known tht the gretest number of bcteri occur in the upper few millimeters of sediment (29), which is the sediment profile most esily resuspended by chnging environmentl conditions. t is interesting tht temperture nd turbidity hd strong positive correltion, which is gin in contrst to the results of Crney et l. (4), who found greter vlues of turbidity in winter thn in summer. There ws no effect of ph on ny of the vribles studied, except on totl coliforms in wter which gve strong negtive correltion. strong correltion ws lso found to occur between slmonelle in sediment smples nd fecl coliforms in wter smples. Temperture, turbidity, nd suspended PPL. ENVRON. MCROBOL. solids did not hve ny correltion with vrious microbiologicl prmeters. Effect of distnce from sewge outfll on wter qulity. n severl of the cnl systems studied, the pollution originted from point sources, i.e., sewge outflls. To determine the chnge in wter qulity in reltion to distnce from source of pollution within cnl system, wter nd sediment smples were obtined ner sewge outfll serving one of the cnl communities under study. The smples of wter nd sediment were tken t distnces of 1, 3, nd 6 feet (c. 3., 91.4, nd m, respectively) from the outfll (Tble ). s expected, the MPNs of indictors nd pthogens in the wter nd sediment smples decresed s function of distnce from the outfll, probbly due to dilution effect. On ll occsions, however, the bcteril concentrtions were higher in sediments thn in the overlying wter, nd most of the bcteri in wter ner the outfll were of fecl origin. Cross-sectionl nlysis of cnl. Tble 6 shows comprison of the bcteril counts obtined from surfce wter nd sediment smples tken cross the width of the cnl t site K27. pprently, the sediment towrd the midpoint of the cnl contins higher percentge of orgnisms thn does sediment on the bnks of this cnl. The number of orgnisms in wter smples ws similr t ll of the smpling points cross the width of the cnl. t hs been shown tht wter in river is homogeneous with respect to microorgnism distribution (31). Studies of polluted freshwter cnl communities in southern Florid hve shown tht the gretest concentrtion of orgnic sludge occurs in the cnl center (2). The pprent concentrtion of bcteri in sediments ner the Downloded from on Jnury 13, 219 by guest

9 VOL. 34, 1977 BCTERL PTHOGENS N CNL COMMUNTES 147 middle of the cnl suggests tht the vlues for ever, only one of the simultneously collected coliforms in sediments my be much higher wter smples ws positive for slmonelle. thn reported in this study becuse, out of ne- The density of slmonelle in sediment smples cessity, our smples were lwys obtined from ws low, however, the highest being 1/1 the bnk of the cnl rther thn from the ml. Slmonelle densities s high s 79/1 cm3 middle. hve been reported in polluted freshwter sedi- MPN of slmonelle. Slmonelle were iso- ments by Vn Donsel nd Geldreich (29). llted 17 of 36 times from sediment smples t though the density of slmonelle in the wter ll of the six sites exmined (Tble 7). How- nd sediment ws rther low, the orgnisms TBLE. Distribution of bcteri in reltion to distnce from the sewge outfll Distnce from the Totl coliforms (MPN/1 ml) Fecl coliforms (MPN/1 ml) Slmonelle (MPN/1 sewge outfll (feet) Wter Sediment Wter Sediment Wter Sediment 8,33 1,383,3 8,7 817, (3.)b 6 1,363, , (91.4)b 8 13,3 17 6,1 <3 3 6 (182.8)b 24 3,3 11 1,1 <3 3 ll MPN vlues re the men of three different observtions. b Meters. TBLE 6. Comprison of microbil popultions cross the width of the cnl t site K27 Totl coliforms (MPN/1 ml) Fecl coliforms (MPN/1 ml) Slmonelle (MPN/1 Loction on lterl ml) section Wter Sediment Wter Sediment Wter Sediment (est bnk) 13,41 8,7 3,82 2,73 <3.3 B 19,99 37, 1,1 97,8 <3 14 C (midpoint) 19,82 878, 6, 92, D 8,1 99, 2;9 12,1 <3 43 E (west bnk) 13,97 23, 2, 18,63 <3 17 Men of smples tken on four different occsions from two different loctions on the cnl. TBLE 7. Serovrs of slmonelle isolted from six cnls nd their reltionship to concentrtions of indictor orgnisms Sttion Smple Month no. H82 Wter Dec. H81 Sediment Dec. H81 Sediment Jn. H81 Sediment Feb. H81 Sediment Mr. H82 Sediment Dec. H82 Sediment Jn. K27 Sediment Nov. K27 Sediment Dec. K27 Sediment Jn. K27 Sediment Feb. K27 Sediment Mr. K27 Sediment pr. 318 Sediment Nov. 318 Sediment Dec. 323 Sediment Nov. 323 Sediment Dec. 324 Sediment Dec. MPN (per 1 ml) of: Totl coli- Fecl coli- Slmoforms forms nelle , 1,1 11 1,6, 28, 3 16, 3, 4 7, 2,4 4 16, 22, 11 4, 92, 7 2,4, 2,6 9 26, 7, 4 92, 2,8 9 22, 2,2 1 3, 3, 9 92, 2,4 9 16, , , , , 63 3 Slmonelle iso- Totl coli- Fecl coli- ltes forms/fe- frssl clcl forms/slforms monelle No. Serovr B B B F F 7 2, 3 B 6 1,314 2 B B 4 1,7 1 F B B B,F F B B B B B Downloded from on Jnury 13, 219 by guest

10 148 GOYL, GERB, ND MELNCK were recovered by strightforwrd isoltion procedures. lso, the bsence of pthogens in smples positive for fecl contmintion is no gurntee tht microbil hzrds re bsent from such res. To quote Crney et l. (4): "Enteric pthogens like slmonell nd shigell my not survive in the esturine environment or my become debilitted or ltered by the low temperture, high slt concentrtion, nd other environmentl influences, so tht selective medi re, in essense, finl blow." The density reltionship of slmonelle nd fecl coliforms in sediment smples ws not constnt, but vried between 1:9 nd 1:2,, with medin of 1:198. f the number of slmonelle in the sediment smple is compred to the number of fecl coliforms in the wter smple, the medin rtio is 1:13 (rnge = 1:.3 to 1:27), which is much higher thn medin of 1 slmonell in mud per 1 fecl coliforms in the overlying wter in freshwter systems (29). The minimum density of fecl coliforms per 1 ml ssocited with isoltion of slmonelle ws 13 for sediment nd 14 for wter. Of the 17 times tht slmonelle were isolted, the fecl coliform concentrtion ws less thn 2,/1 ml 6 times. Slmonelle hve been isolted in the pst from wter with low coliform counts (2, 26, 27). Slmonelle were lwys isolted when the fecl coliform concentrtion ws >2,/1 ml, except on two occsions when the wter nd sediment smples hd fecl coliform vlues of 2,2/1 ml nd 17,/1 ml, respectively. The verge men rtios relting pthogens to indictors were 1 slmonell to 4 totl coliforms nd 13 fecl colifonns for wter smples nd 1 slmonell to 29,128 totl coliforms nd 46 fecl coliforms for sediment smples. Dt collected from field investigtions throughout the United Sttes showed tht slmonell isoltions could occur with nerly 1% frequency when the fecl coliform concentrtion ws >2,/1 ml (8). The isoltion of greter numbers of slmonelle from the bottom sediments thn from the overlying wter in the present study is supported by the dt of Vn Donsel nd Geldreich (29), who isolted slmonelle from 22 of 48 sediment smples from smll strems nd recretionl lkes, wheres only 4 of the simultneously collected wter smples were positive for this orgnism. Similrly, of the 19 smples of sediment nd river wter exmined over 1- yer period, pproximtely 9% of the slmonell isoltes were from bottom sediments (18). Hendricks (17) demonstrted tht certin strins ofslmonell nd Shigell cn metbo- PPL. ENVRON. MCROBOL. lize substrtes present in queous extrcts of bottom sediments t 24C or below. Svge (23) found extended survivl time of S. typhi in sterilized freshwter mud. Thus, survivl of these orgnisms cn be expected to be longer in the sediment of the cnl thn in the wter column. Only two slmonell serovrs were isolted during this study. t is interesting to note tht both B nd F serovrs were isolted from the sites with the highest coliform counts, wheres only type B ws isolted from lightly polluted sites (no. 318, 323, nd 324). Of 33 isoltes, 27 were type B. On one occsion, both types B nd F were encountered in single sediment smple from site K27. Type B is the most frequently reported serovr in disese outbreks due to slmonelle in the United Sttes. The observtion tht 1 to % of ll the fecl coliforms recovered from recretionl wters cn be identified serologiclly s enteropthogenice. coli (9), coupled with n incresed rte of recovery of indictor orgnisms s well s of slmonelle, led us to believe tht sediments cn ct s reservoirs of proven pthogenic bcteri. lthough bcteril stndrds for judging the potentil helth hzrds for recretionl use of mrine wters hve never been unequivoclly greed upon becuse of the need for epidemiologicl studies, rbitrry bcteril stndrds hve been utilized in the United Sttes. The Ntionl Technicl dvisory Committee on Wter Qulity Criteri hs recommended limit of 1, totl coliforms per 1 ml nd 2 fecl coliforms per 1 ml for recretionl wter (7). This vlue ws regulrly exceeded in the three sites tht utilized collection systems. We believe tht the occurrence of lrge numbers of enteric bcteri nd viruses (C. P. Gerb, S. M. Goyl, E. M. Smith, nd J. L. Melnick, Mr. Pollut. Bull., in press) in the cnl bottom sediments is significnt in tht it my gretly ffect the overll long-term wter qulity of the cnl system. n previously reported study (1), we demonstrted tht bcteri of fecl origin survived for much greter period of time in sediment obtined from these cnls thn in the overlying wter. Viruses re lso known to persist for longer periods of time in mrine wter when ssocited with solids (12), nd dsorbed viruses re lso infectious (2). Thus, evlution of helth hzrds should be concerned with the presence of pthogens in the sediment s well s in the wter column, especilly in such shllow wter s present in cnl communities tht re hevily used for recretionl purposes. The hevy bot trffic Downloded from on Jnury 13, 219 by guest

11 VOL. 34, 1977 contributes to the continul resuspension of sediment in the cnls in ddition to the effects of currents nd storms. The very design of cnl communities, with mny ded-end cnls, probbly ggrvtes the wter qulity problem by reducing tidl flushing ction. This ids in the build-up of wste mteril in the bottom of the cnls. These communities re too remote for connection to mjor sewge tretment fcilities vilble in lrger cities long the cost of Texs, nd septic tnks or smll, pckged tretment plnts must be relied upon for sewge tretment. The results of this study indicte tht dischrge of treted wstewter could pose potentil public helth hzrd. Better design criteri of cnl communities, such s elimintion of sewge dischrge into or ner the cnls by construction of longer outfll pipes or construction of cnls to llow better tidl flushing, should be encourged to reduce the ccumultion of pthogenic microorgnisms in the wter nd sediment. CKNOWLEDGMENTS This reserch ws supported by grnt from the Ntionl Ocenic nd tmospheric dministrtion's Office of Se Grnts, Deprtment of Commerce, through institutionl grnt to Texs &M University. The technicl ssistnce of Clrence Johnson, Bob Hinton, nd Jim Dy nd the computer progrmming ssistnce of George Terrell re grtefully cknowledged. BCTERL PTHOGENS N CNL COMMUNTES 149 LTERTURE CTED 1. mericn Public Helth ssocition Stndrd methods for the exmintion of wter nd wstewter, 14th ed. mericn Public Helth ssocition, New York. 2. Boring, J. R., W. T. Mrtin, nd L. M. Elliott soltion of Slmonell typhimurium from municipl wter, Riverside, Cliforni, 196. m. J. Epidemiol. 93: Crlson, G. F., F. E. Woodrd, D. F. Wentworth, nd. J. Sproul Virus inctivtion on cly prticles in nturl wters. J. Wter Pollut. Control Fed. 4:R89-R Crney, J. F., C. E. Crty, nd R. R. Colwell Sesonl occurrence nd distribution of microbil indictors nd pthogens in the Rhode River of Chespeke By. ppl. Microbiol. 3: Fust, M..,. E. otky, nd M. T. Hrgdon Effect of physicl prmeters on the in situ survivl of Escherichi coli MC-6 in n esturine environment. ppl. Microbiol. 3: Fechem, R Fecl coliforms nd fecl streptococci in strems in the New Guine Highlnds. Wter Res. 8: Federl Wter Pollution Control dministrtion Report of the Committee on Wter Qulity Criteri. U.S. Government Printing Office, Wshington, D.C. 8. Geldreich, E. E Bufflo Lke recretionl wter qulity: study in bcteriologicl dt interprettion. Wter Res. 6: Geldreich, E. E Microbiologicl criteri concepts for costl bthing wters. Ocen Mngement 3: Gerb, C. P., nd J. S. McLeod Effect of sediments on the survivl of Escherichi coli in mrine wters. ppl. Environ. Microbiol. 32: Gerb, C. P., nd G. E. Schiberger Biscyne By: bcteriologicl dt interprettion. Fl. Sci. 36: Gerb, C. P., nd G. E. Schiberger Effect of prticultes on virus survivl in sewter. J. Wter Pollut. Control Fed. 47: Gonchriuk, E.., G. V. Svchenko, nd M.. Levynt Decontmintion of sewge wters contining typhoid fever pthogens in n experimentl instlltion for underground filtrtion. Gig. Snit. 31: Gry, E Survivl ofescherichi coli in strem wter in reltion to crbon dioxide nd plnt photosynthesis. J. ppl. Bcteriol. 39: Greenberg,. E Survivl of enteric orgnisms in se wter. Public Helth Rep. 71: Grimes, D. J Relese of sediment-bound fecl coliforms by dredging. ppl. Microbiol. 29: Hendricks, C. W Enteric bcteril metbolism of strem sediment elutes. Cn. J. Microbiol. 17: Hendricks, C. W ncresed recovery rte of slmonelle from bottom strem sediments versus surfce wters. ppl. Microbiol. 21: Hendricks, C. W., nd S. M. Morrison Multipliction nd growth of selected enteric bcteri in clen mountin strem wter. Wter Res. 1: Johnson, G. V., J. Ky, C. Morrissey, nd K. W. Schng Pollution in Dde County: sttus report, p n Conference on the Mtter of Pollution of the Nvigble Wters of Dde County, Florid, nd Tributries, Embnkments, nd Costl Wters, October 2-22, 197. U.S. Deprtment of the nterior, Federl Wter Qulity dministrtion, Wshington, D.C. 21. Rittenberg, S. C., T. Mittwer, nd. vler Coliform bcteri in sediments round three mrine sewge outflls. Limnol. Ocenogr. 3: Roper, M. M., nd K. C. Mrshll Modifiction of the interction between E. coli nd bcteriophge in sline sediment. Microb. Ecol. 1: Svge, W. G. 19. Bcteriologicl exmintion of tidl mud s n index of pollution ofthe river. J. Hyg. : Syler, G. S., J. D. Nelson, Jr.,. Justice, nd R. R. Colweil Distribution nd significnce of fecl indictor orgnisms in the upper Chespeke By. ppl. Microbiol. 3: Schub, S.., nd B. P. Sgik ssocition of enteroviruses with nturl nd rtificilly introduced colloidl solids in wter nd infectivity of solids-ssocited virions. ppl. Microbiol. 3: Seligmnn, R., nd R. Reitler Enteropthogens in wter with low Escherichi coli titer. J. m. Wter Works ssoc. 7: Smith, R. J., R. M. Twedt, nd L. K. Flnign Reltionship of indictor nd pthogenic bcteri in strem wter. J. Wter Pollut. Control Fed. 4: Spinco, D. F Elevted temperture technique for the isoltion of slmonell in strems. ppl. Microbiol. 14: Vn Donsel, D. J., nd E. E. Geldreich Reltionship of Slmonelle to fecl coliforms in bottom sediments. Wter Res. : Weiss, C. M dsorption of E. coli on river nd esturine silts. Sew. nd. Wstes 23: Witzenhusen, R us welcher Wssertiefe soll die Wsserprobe ffir die bkteriologische Untersuchung entnommen werden? Zentrlbl. Bkteriol. Prsitenkd. nfektionskr. Hyg. bt. 1 Orig. 16: Downloded from on Jnury 13, 219 by guest