Document ppVE1xZYxZkg1b4xy52kLE67d

Stfim bm*? ft. tti--1*7 (tni) Qfcr infif nni*n - Toxicity and distribution of Aroclox 1254 in the pink shrimp Pentuut duorarum* ' D. R. Nimmo, R. R. Bulokmav, A. J. Wiuox, Jr. tad J. Foxnm byfaeniftoaUt rrctecisoa Agenqr, Galf Braes* Lsboratoiyi Sabin* Island, Glf Breeas, Ihrth, USA Abstract The polychlorinated biplwnyl Arocloi 1254 u re leased in mi accidental leatape of Ucat-cxrJuingc flukl from an IndntrUpUat, into tho Ktcambia River, near Fcnaacola, Florida, USA. This malrrUl m carried downstream, Mid is now found in the fauna of Escambia Bay and lte contiguous mltn, prime nursery area* for fishes and invertebrates auch aa peoaeid ahrimp. The significance of pollution by this cbomleaf waa assessed by establish-ng toxicity lovels. determining tontea of entry, ana investigating ita movement and distribu tion In various tissues of shrimp under controlled conditions in the laboratory. Aroclor 1234 added to the water waa toxio to the juvenile pink ahrimp Peaaeu* inorantm at a ooacentratioo of 1.0 part per billion within 15 days, bat waa leas Registered trademark. Monsanto Company, St. Louis, Mkaouri. Mention of commercial products docs not oonatitou endorsement by the Environmental Protection Agency. * Coatribatwa Bo. IB, Gulf Brtare Lahoretey. toxio to adult pink ahrimp. Shrimp obtained the contaminant from water and food and eonoenlratod it to 510.0 parts par million in the hcpatopanercaa. Areolar 1234 residue data from ahrimp ooQeetod in the estuary are iaalodad in lha atudy. btwiuelim Since 1900, pesticide toxicologists and ecologists have become increasingly aware of polychlorinated biphenyls (PCBa). First discovered in fishes, feathers, and boman hair (Jensen, 1966), residues have since been found in many organisms from diverse areas of the world. Structuredly. PCBs resemble chlorinated hydrocarbon pesticides auch as DDT. aod are widely used in formulating plastics, resins for rubber-based lacquers. Tarnishes, paints, lubricant*, beat-transfer fluid* and electrical insulators. PCBs are relatively v Uf.1. Residues of Aredor 1254 (is ppm) found bt ahrimp bepatopsBeraaeee from Escambia Bay and contiguous waters during 1969/1870. Each sample listed represents composite tinass of at least 6 individuate '* Xsitee BtsUwr. Tat U DSW 255135 V STLCOPCB4060826 > D. R. Nuuso st aL: Araslor hi ftmiw dm Hi. Fig. t. Fsriihw ef Araslor 1254 0a ppm) la sediment* ftoa Fsesmbia Bay tad (cottam* watsrs dome 10M/197O. NJ>.: less thaa CtU pom insoluble in voter, bat soluble in lipid and lipid sol vents. Is addition to their thermal stability they are also resistant to acid and base, and therefore, persist in the environment. PCBs are toxic to trout and blue gill (epp. not given) -- Ovstafsox, 1070; shrimp (Penoevs dvoronua) and oysters (Crrosostree virginiea) -- Doss ct al., 1870; and a fwh (Jjsqodon rhomboidn) -- Hanskx et al., 1971. Also, a 1*CB used as a binder in epoxy paint vas toxic to chickens (Guctafsox, 1970). Abnormally thin-abclicd eggs of birds in Great Britain and North America were associated with residues of chlorinated hydrocarbons including the PClis (Kisebrouoii ct at., 1908). In 1909, a 1*CB (Aroclor 1254) was discovered as a contaminant in water, sediment and fauna of Escambia Bay, Florida (Duke ct al.. 1070). One source of this material was traced to an accidental leak in a beat-cxcltangc system of an industrial plant located acverat kilometers upstream in Escambia Itiver. It is now present in estuarine organisms, including shrimp captured from Escambia Bay and contiguous waters (Fig. 1). Sediments from the river and upper bay spjtear to be a reservoir for the compound (Fig. 2). In earlier experiments, shrimp exposed to these sediments for 30 days accumulated the chemical (Ximmo et al., 1871). In this paper wu report toxicity oT Aroclor 1254 hi water, rates of accumulation from food and water. and distribution f this PCB in tha organs of the pink shrimp Penaetu duontrmm. Materials sal methods Shrimp for laboratory studies were obtained from two sources. Juvenile (2.5 to 3.8 cm) pink shrimp (Penaeut drtorrnium) were collected with a small net from Santa Rosa Sound at Pcnsaeola Beach, Florida, in June through September. Adult pink shrimp from Tampa, Florida, were purchased from a live-bait dealer. Background concentrations of chlorinated hy drocarbon compounds in tho liepstopancrcasc* o( nil shrimp never exceeded 0.6 parts per million (ppm); wholo-body residues were less titan 0.01 ppm. All shrimp were acclimated in flowing sea water for several days in the laboratory. Juveniles feel on detritus carried in by the flowing unfdtcrcd sea water and adults were fed mullet (JtrngS ccphiilu*) muscle containing less than 0.03 ppm organochlorinc com pounds each day. Beach sand with no detectable orgsnochlorme compound* vas provided as a sub strate for the shrimp. ' Shrimp were exposed to Aroclor 1254 (hereafter called Aroclor) in flowing-water systems. The Aroclor was dissolved in polyethylene glycol 200, infused into the flowing water with syringe pumps, then mixed by DSW 255136 STLCOPCB4060827 Vtl. 11. Ha. J. I'JTt 0. It. Nimmo ri si.: Aroolnr in /Vh>-mji Juormrum iua a series of balTlcs ns it Ihm-cil into nqtmria. 'J'lio volume of the aquniii varied front IS to 1U0 1 commensurate with the numbers and sizes of lest Animals anil flow rate of water. Animal to voluino ratio was 1 animal per 21 water. Concentrations of Arodor were routinely measured by gas chromatography. No attempt was mado'to control salinities which ranged from 25 to 32X.. bat electric aquarium heaters were used to main tain water temperatures between 20* and 30 *C. Fig. 3. Aroclor chromatograms. (A) Aroclor 1254 standard, (B) Aroclor 1254, recovered from Pcnar.ua duorantm hepntopancreas after shrimps hnd been fed fish containing material (soe Table 4). Concentrations of DDT and its metabolite* were negligible, therefore, no attempt was m.ido to soparate them from Aroclor isomer*. Gas flow 25 ml/min, nitrogen; injection temperature 210 *C, ovrn temperature 190 "C, detector temperature 210 C; IP electron rapture detector; 162.4 x 0.317 cm glass-column packed with 2% OY-i on 100/120 Gas Chrora Q Concentrations of Aroclor in shrimp were deter mined from pooled samples by gas chromatography. When a group of 10 .shrimp was exposed to a constant concentration of Aroclor in flowing-water, individual residues didcrcd by a factor of 10. Consequently, laboratory analyses are from composite samples of at least 10 individuals, unless stated otherwise. All analyses on Penttcus dvorarum from Escambia Bay anti contiguous waters wero on composite oamplca of at 5 individuals. IVix'iuling on tyjh-. and weight of tho sample-1*, four inclluxis of pr-|iaration were employed. (1) Sample* of slirimp or fixsl iteins larger limn 1 g '-ere mixed with anhydrous sodium sulfate in a blcmlcr arid extracted for 4 h with petroleum ether in a Soxhb-t apparatus. Extracts were concentrated and eluted from a Florisil column with 0%' ethyl ether in petro leum ctlicr. (2) Samples less than 1 g were analyzed by a modification of the micro-method of Esc(private communication). Samples were weighed in Duall1 tissuo grinders and extracted with three 2.0 m! portions of acetonitrile. The acetonitrile extracts ive. c coinhinril and diluted with C ml of 2% Na, SO, in dist illed water, then agitated and extracted with *.hn; 2.0 ml portions of hcvanc. These extracts were com bined and concentrated to about 0.5 ml, then tran ferred to a Sizo "B" Chromaflex1 column contair.n 1.5 g of Florisil topped with 1.3 g of anhydrous sodium sulfate. The residue was eluted from the column wiiii 20.0 ml of 1 % ethyl ether in hexane. (3) Water ran p! i were extracted with petroleum ether, tlicn the extra-. ** were dried with anhydrous sodium sulfate and ic duced to an appropriate volume. (4) Sediments were analyzed by the method of KtUMO ct nl (1071, All eluates were adjusted to an appropriate volume for analysis by electron-capture gas chromatographequipped with OV-1 columns. Quantitation of Aroclor 1254, a multiplo-peakcd compound, was made by averaging the heights of 5 major peaks which had retention times relative to aldrin of 1.31 (/ F), 1.57 (K), 2.32 {VIII). 2.74 {IX) and 3.27 (A') (Fig. 3j Interference from DDT was negligible duo to t!.c relatively high residues ofAroclor J 254 in most rain pies Laboratory tests indicated recovery rates above S0`,o. but data in this report do not include a correction fac tor for recovery. The presence of Aroclor 1254 in shrimp and sediments was verified by mass spectro soopy at the Environmental Protection Agency La boratory, Athens, Georgia. Results Acute and chronic biosassays Acute toxicity tests at this laboratory showed that Aroclor was about one tenth ns toxic to juvenile Pcnat.ua duararum as DDT (Table 1) For ex.,in- :10.0 parts per billion (ppb) DDT in the water killed 100% of a population of shrimp in Ofi h. wbcicns 100.0 ppb in tho water was necessary to obtain the aamo results with Aroclor. In chronic flowing-water bioassays, Aroclor at 0.94 ppb killed 51% of tho juvenile shrimp (2.5 to 3.8 cm) within 15 days (Table 2). Juvenile shrimp were more sr.nMtivc to Aroclor than adults. Exposure to 3.5 ppb for 35 days resulted in a mortality of .>0% in a group of adult slirimp (0.5 to 12.0 crn). Tho data 1 Kontes Glass Co., ViuoUml, N. J., USA. to* DSW 255137 STLCOPCB4060828 1*4 D. R. Nnnto ot iL: Aroelor in Penmen* iwerwrum ' A`e> > show the need for challenging soveral stages in the lifo cycle of shrimp with chemicals such as Aroclor. We hnve observed that symptoms of Aroclor poisoning in shrimp are different from those of roost organochlorinc insecticides. Pink shrimp which we exposed to 0.15 ppb or more DDT showed nervous impairments such os tremors, loss of equilibrium and, finally, paralysis as defined by cessation of locomotor movements. In tests with Aroclor, regardless of its concentration, shrimp Bhowtd delayed mortality and died at a rate of one or two per day with no apparent prior symptoms of poisoning. Like others (Duke, et al., 1970; Wildish, 1970), wo suggest that crustaceans may be more susceptible to the chemical during molting. Accumulation and Iranifar of Arochrr ir, t'.z The uptake of Aroclor from wale;- * Penaent duorarum (3.8 to 7.6 cm) and the f.' - tion to tho hcpatopancrcas, whole body nr.-J r. h- dominal musclo was. measured (Fig. 4) Ac ut was linear with tiir.o in the hcpatopuiu. -> p 1 i and wholo body (r-- 0.90). but a plateau was rr -.< --.-cl Table 1. Penman duorarum. Comparison of toxidlies of p, p' -- DDT nrd Aroclor 1254 lo shrimp in flowing-voter teste, Deem temperature and salinity of sea u-altr in DDT experiment vert 24 *0 and 231L, respectively; for Aroclor 1254, 10 mC and 31 X. DDT* Teat concentration (ppb) Mortality 43 h 90 h (%) 1%) Aroclor 1254* Teat concentration (ppb) Mortality 48 h 90 h (%> (%) 10.0 1.0 0.5 0.1 Control 100 100 30 80 0 40 10 20 00 100.0 10.0 1.0 Control 0 100 00 00 00 Personal communication, J. I. Lowe, Environmental Protection Agency, Gulf Breeze. Florida 32501. USA. *Dcke et *L, 1970. EXPOSURE TIME (days) Pig. 4. Penaeus duoraram. Rates of absorption of Aroclor 1 .54. in various tissues of shrimp exposed to 2.5 ppb uf the i!. 'rnual in flowing water. Unexpected shrimp showed no dotci <, residue, r -- correlation coefficient Table 2. Remits of tkron'C bioassays with Aroclor 1254 and Iht pink shtimp Penaeus duorarum in flowing u\iter Shrimp rcrstium-tclson length (cm) Concentration* Average (Pfb) Lalinily (X.) Average No. of teat Kcplicatc3 Days tomperature individual exposed rci Average mortality (%) Level of significance 2.5 - 3.8 2.5 - 3.9 2.5 - 3.9 2.5 - 3.8 2.5 - 3.8 4.2 - 7.2 4.2 - 7.2 4.2 - 7.2 0.C - 9.0 0.G - 9.0 7.C - 6.5 7.0 - 8.5 9.5-12.5 9.5-12.5 Control 32 0.57 32 0.94 32 9.4 32 19.0 32 Control 1 29 2.4 29 3.1 29 Control 2!) 4.7 29 Control :n 4.0 31 Control 28 3.5 28 29 29 29 20 29 23 28 28 20 20 29 29 20 20 * Average of at lcaat three determinations. * Student's (-test. * Chi-square. 65 5 16 12 20 2 15 30 o.io- 45 3 15 51 0 00> 20 2 15 90 0.001* 20 2 15 100 0.001* 23 1 32 4 -- 20 1 17 05 0.00!' 25 1 32 SO 0.001* 43 1 63 2G -- 40 1 63 83 0.001* CO 1 IS 9 -- . CO 1 18 41 0.001* 50 1 33 8 -- 50 1 35 60 0.001* DSW 255138 STLCOPCB4060829 rot. 11. a*. 3. mi D. R. Kimmo et iL: Aroolor in Pauuut duormrmm (00 o 00 w 400 ^ tr aoo 2 u O cc joo < < too O l'j. ELIMINATION TIME (weeks) Fig. 5. Penacxj duorarum. Rates of elimination from hepatopancreaa and subsequent inorraaa in remaining lmoo. i-i.'.m; were exposed to 7.5 ppb Aroclor 1254 in flowing water for 1C day*, then plaood in Aroclor-Cree environment. Coir.poim* ticaue cample* from S individual* were analyzed for each determination. Unexpoead ahrimp showed no delectable residue* r - eorrelation coefficient |/'JV C jt.'C. in the muscle within 2 days, with little increase there after. Residues in the hcpatopancrcas reached 510.0 ppm after 22 clays and represented a 2.04 x 10* in crease over the 2.5 ppb Aroclor in the test water. During this experiment, 50% of the exposed and 7% of the unexposed shrimp died. In a subsequent experiment, most of tho Aroclor was lost from the hcpatopancrcas and transferred to other tissues (Fig. 5). Adult shrimp (9.5 to 11.5 cm) were first exposed to 7.5 ppb Aroclor in tho water for 1C days, then placed in an Aroclor-fieo environment for 5 weeks. Total weight (pg) in the hcpatopancrcas decreased by 80% in 5 weeks, but that in the remain ing tissues almost doubled. Wholo-body loss was from 731 to 4C0 pg or about GO % in 5 weeks. A slightly different picture exists concerning tho loss of Aroclor from tho tissues if wc express tho amount in j*arts per million (Fig. 5). Aroclor (in ppm) showed little change in tissues other than tho hepatopanereas during jw'.t cxjiosuro. In contrast, tho rato of elimination from the hcpatopancrcas was constant and linear with time (r 0.9'J), tho biological halfhfo in this organ being 17 days. Aroclor in more pcraislcnt in the other tissues of rhrimp than DDT, the inaectieido being completely eliminated in 3 weeks (Xixxio ct oh, lb?uj. tVhilo tho Pcnucuo duorarum were held in the Arocloi-free environment, 23% of tho exposed shrimp died, with no loss of tho unoxposod. Accumulation in body organs Residues found in laboratory experiments are com pared with those in natural populations of shrimps in Escambia and Pensacola Bays in Table 3. In all tests, tho shrimp incorporated the chemical. The propor tion of Aroclor in tissuoe of shrimp which were expo :d to 0.2 ppb in tho water for 50 days was nearest to that found in shrimps captured alive from the bays Tho distribution of Aroclor in the tissues of shrimp is much the samo os DDT, maximum amounts oc curring in the hcpatopancrcas and least in abdominal muscle or cxoskelcton (Nimmo ct al., 1970). (lencrall> . the distribution of Aroclor in tho tissues of Pcimrus duorarum corresponded to the amount of lipid . ': tissues. Wo believo water and food are sources of ArocI-r to shrimp, but wo da not know which c-w tribute.; more. Fakfante (19G9) summarized earlier work on tho feeding habits of shrimp and rc|>orlcd that the three commercially-important pcnacid shrimp*, pink Pcnaeus duorarum, whilo P. selijrrus, and bro P. azlecu*. aro omnivorous. Some of tho contents found in digestive tract* by other investigators iiuin.lo in organic debris, detritus, and a variety of algao, in cluding diatoms. Aroclor attached to detrital material in aquaria or in field substrate* was probably ingested by the shrimp. DSW 255139 STLCOPCB4060830 100 D. R. Ndmio et *1.: Arvdor in Ptnatut duormrun, t* cr. Table 3. Distribution of Aroclor 1254 in tissues of exposed Ptnaeus duontnm tritick bad accumulated chew.ua! from m.V food and in penaeid shrimps from natural populations tit Iks Pensacola estuary, Florida, USA Method* of exposure llcpato- Ventral Digcetivo pancreas nerve tract PP5 Heart Cilb Exoakeloton Abdc.'ninl inusi'. Water l*ink shrimp exposed to 35 ppb Aroclor in water for 35 days Pink shrimp exposed to 0.2 ppb Aroclor in water lor 90 days Food Pink shrimp fed spot* (43.0 ppm whole body) for 16 days Pink shiimp fed spot (field-captured, 0.2 ppm whole body) for Hi day* Pink shrimp fed croskor* (0.08 ppm in mueele) for 50 day* Natural population* Pink shrimp captured 10. I. 1970* Pink shrimp captured 3. IV. 1070* White shrimp captured 28. VIII. 1970* Brown shrimp captured 28. VIII. 1070* 108 30 148 0.6 64 16 4.6 17 08 120 U 32 3.2 M 05 24 16 <0.1 1.0 6.4 1.1 0.6 05 4.0 1A 14 6.7 77 59 14 24 1.4 0.8 25 38 6.5 05 03 0.2 15 04 0.6 -- 05 1.0 44 1.4 0.6 05 0.2 0.8 0.8 3.1 2.2 * Tho spot Leiostamus xanihurus were previously exposed to 5.0 ppb Aroclor 1254 in th* water for 12 days. * Atlantic croaker Micropogon undulatus were captured in Escambia Bay, Florida. * Pensacola Bay. * Escambia Bay. 15 0.7 5t <0 1 e.c 09 * 0.1 1.3 0.0 Table 4. Percentages* of 5 peats in Aroclor 1254 recovered molecules or differential solubilities in the various from water, fish and Pcnarus duorarusn systems. Item Peak (%) IV V VIII IX X Standard 10.0 185 25.0 22.2 20.0 Water (302. S) 8.2 15.6 30.0 224 23.1 Fish muscle* 5.1 10.8 27.4 27.9 28.4 Shrimp hopatopancress* 2.8 10.9 23.9 31.1 31.1 `P^.kfifhL- X 100. sum of 5 peaks * Tho Atlantic croaker if\cropo</on undulatus were captured front Excambia B.iy and contained 0.C8 ppm Aroclor 1254. * Tito shrimp Penatus dnorarum wore fed Atlantic croaker muscle. Wo investigated' differences in the proportion of Aroclor peaks with respect tho standard; the chango is greatest in the hcpatopancrcos of shrimp (Kig. 3; Table 4). Heights of 5 peaks used for quantitation of the chemical show '.he greatest reduction in peak* IV and V, witli some increase in IX and X. Wo do not know whether this reflects actual alterations in tho Results of field studies Distribution of shrimp in tho estuary in relation to salinity is a factor which regulates the amount of Aroclor in tho body (l'ig. i). The brown shrimp Penatus azteevs from upper Escambia Hay had the highest residues (132.0 ppm in the hej-atr-pun'-n as). Tho white shrirnp P. setifrrus from the mouths of small streams emptying into Escambia Bay h.vl a maximum residue of 59.0 ppm. The bight.`t ri niuc in the pink shrimp P. duorarum captured in Pons icolu Bay wos 15.0 ppm. P. srtiferus is most ab'in-lunt m low salinity water* of less than 10TJ. and i' . us occurs mostly in waters of 10%. or more, (he n'-undanco of P. duorarum is not as dependent on salinity (Faiifantb.1909). Although this distribution may very with locale, t3q>cs of substrate and seasonal tempera tures, shrimp wit h the highest residue.-; in this st ud v v ere those captured in tile lower salinities. Bo.au .c higher concentralions of Arocloi occur in the sediments o: ujqier Escambia Bay (I'hg. 2), it is possible that burrowing activities of brown shrimp in these sedi ment* could have caused additional absorption of leached chemical through tho gills (Ximmo et nl., 1071) as well as ingestion of contamii rued fotni. SW 255140 STLCOPCB4060831 FW. 11, .Ye. 3.1D71 1>. R. MuutO tl al.: Aradar ii /Vaanu duornrum Il>7 DUnufian and ccnrliuimu In our invcslipntions. (hero h.u been no cvhlcnco that Aroclor in the water, xrtliiiirnU, or biol in Etcambia Hay was toxic to shrimp. We found no dead or dying shrimp in area* of "fish kills" which occurred frequently during rummer months of tho past two years. Aroclor in water sattiplot collected-IK cm above the scilittu'iils in the trpjicr Hay was below that considered toxic to shrimp, but it wu dclectablo (0.00 ppb in unfill ered water). It probably leached from the sediment* or was attached to suspended particulate matter. Adnlt shrimp in livo capes placed dircctlj' on sediments in upper Escambia Bay for 3 weeks did not die nor did tho "controls" held 48 cm above in an uncontaminated substratum. Shrimp on lower sediments accumulated almost 3 timoa more Aroclor (6.7 ppm in the hcpatopancrcas) than did controls. Nevertheless, our laboratory investigations show that Aroclor 1254 in solution is toxic in the 1 ppb range to shrimp. Therefore, tho occurrence of this chemical in tho water of Escambia Bay or in other estuarine areas is reason for concern. Wo also believe the residues found in shrimp from the Escambia Bay are high enough to be of importance, although we have not found a correlation between residues and mortality. If postlarval or juvenile shrimp were exposed directly to the sediments in upper Escambia Bay for a period of weeks, a threat could exist because of availability of PCB-ladcn detritus and also the leaching of the chemical at the water-substrate interface. We ore now investigating this possibility. Deaths of shrimp due to this or any other oontaminant in natural environments would be difficult to observe. Except as larvae, shrimp aro primarily benthic, secretive animals, and hide by burrowing in the sediment. If they are active at night, they usually remain below the substrate by day. Hero, they may obtain higher concentrations of Aroclor than when swimming, and if they die, dead shrimp do not surface after dying as do fish, rather they decompose rapidly or arc quickly eaten by predators. Aroclor occurs in the tissues of shrimp which were captured several kilometers from the original sources of the material in Escambia Bay (Fig. 1). This suggests the potential of this material to be dispersed through the ecosystem, and it might bo available to man through his seafood. Wo believe this contamination should serve as a warning to increase monitoring of the environment for Aroclor and related industrial mate rials. . Summary . 1. A concentration of 1 0 part per billion of Aroclor in tho water kills tho juvenile pink shrimp Penatus iuoranaH within 15 day* in tho laboratory. Adult shrimp aro not susceptible, but higher concentra tion* of 2.4 to 4J ppb kill within 17 to 53 days -- depending on tho maturity of test individuals. 3. In Inliomlory train in which Aroclor was added to tho water, P. dunrurum absorbed tho material and rnnccntralcd it in Die hcjiatopancreas. Sulrscqucntjy, it was transferred U> other tiwniCK, then lost. It -was moro persistent in the tissues of shrimp than the chemically-related pesticide, DDT. ' 3. Aroclor was absorbed from tho water and its subsequent distribution in tissues was similar to that found in wild shrimp from contaminated areas. In the laboratory, shrimp aluo obtained tho Aroclor from food, and wo concludo that both souroes aro available to shrimp in tho Pensacola estuary. 4. Concentrations of Aroclor in P. ivorarum from tho estuary appear to reflect distribution patterns in shrimp. Aroclor in shrimp captured at considerable * distances (up to 24 km) from tho original source demonstrate the potential for dispersion and concen tration of this material in an oeoayatem. Literature died Dexx, T. W., J. I. Lows aid A. J. Wilson. Jr.: A poly chlorinated biphonyi (Aroclor 1254) in the water, sediment, and biota of Eecambia Bay. Florida. Bull. Envir. Contam. Toxicol. 6,171--180 (1970). . Fakvaktk, I. P.: Western Atlantia shrimp* of the genus Penaea*. Fishery Bull. Fish Wild!. Serv. U.S. C7, 481--491 (1000). Gustafson. C. G.: PCB's-prevslcnt and persistent. Envir. Set. Technot. 4. 814--810 (1070). Hansen, D. J., P. R- Parrish. J. 1. Lowe. A. J. Wilson, Jr. and P. D. Wilson: Chronic toxicity, uptake, and reten tion of Aroclor 1254 in two estuarine fishes. Bull. Envir. Contam. ToxicoL C, 112--119 (1071). Jexszx, 8.: Report of a new chemical hatard. New Sci. 32, 612 (1000). Kruuo, D. R., A. J. Wilson, Jr. and R. K. Blackman: Jjocaliznlion of DDT in tho body orgnns of pink and wliito shrimp. Bull. Knvir. Contam. Toxicol. 5. 333--341 (1070). --, 1*. D. Wilson, It. It. Blackman ami A. J. Wilson, Jr.: PolyohlorinAtod biphenyl absorbed from sediment* by fiddler crabs and pink shrimp. Nature. Lond. 231, 50--52 (1971). RisEsnouou, R. W., P. Hi tenk. D. It. Plakall, S. G. Her man and M. N. Kirvlx: Polychlorinated liiplienyls in global ccosyr.tem. Nature. Lond. 220, 100S--1102 (IDOx). Wildish, D. J.: Tlie toxicity of polychlorinated biplicnyl* (PCB) in aoa water to Oammaru* oeeauicut. Bull. Envir. Contam. ToxicoL 5, 202--204 (1970). First author's address: Dr. D. R. Kimmo Environmental Protection Aganey Gulf Breeze Laboratory Sabine Island Gulf Breeze, Florida 32501 UNA Data of final manuscript acceptance: June 23, 1071. Communicated by J. Runt. Xlisrui ' DSW 255141 STLCOPCB4060832