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SUBMITTED BY: PREPARED BY: APPROVED BY: ARm-0503 E G & G, Bionomics Aquatic Toxicology Laboratory 790 Main Street Wareham, Massachusetts June, 1978 Brenda F. Wilson (^fvL't\Jux ^ lu)i Aquatic Biologist Stephen J. Ells , au AquStic Toxicologist George A. Cary 003772 SUMMARY OF HISTOPATHOLOGICAL EXAMINATIONS OF FATHEAD MINNOW (Pimephales promelas) EXPOSED TO 78.03 FOR 30 DAYS. FC-'/ZJ' RESEARCH REPORT SUBMITTED TO 3M COMPANY ST. PAUL, MINNESOTA REPORT #BW-78-9-301 SUBMITTED BY E G & G, Bionomics Aquatic Toxicology Laboratory 790 Main Street Wareham, Massachusetts September, 1978 003773 INTRODUCTION An "egg and fry test" was conducted between March 31 and May 4, 1978 (Bionomics Report #BW-78-6-175, June, 1978) to assess the sub-lethal effects of 78.03 on fathead minnows (Pimephales promelas). Effects on egg hatchability and on survival and growth of fry were measured. To further investi gate possible effects due to exposure to 78.03, histopathological examinations of exposed fish were also performed. The results of these examinations are reported here. MATERIALS AND METHODS Upon termination of the egg and fry study, five fish from each replicate of the high 78.03 concentration (100 mg/, nominal) and control were preserved in 10% buffered formalin and sent to the Environmental Pathology. Laboratories, Inc. Carolina, Rhode Island. The fish were examined for gross lesions, and sagital sections were prepared by a pathologist. Fish were placed with indentifying numbers into processing cassettes, dehydrated, cleared and infiltrated on an Auto-technicon tissue processor using the method of the Armed Forces Institute of Pathology. The fish were then placed in a vacuum oven and subsequently embedded in paraffin. All blocks were sectioned at 6 microns: one G03774 2 slide was prepared from each block and stained with hematoxylin and eosin. Special staining procedures such as PAS, Trichrome and Acid Fast were used occasionally when requested by the pathologist. All blocks were sealed with paraffin and stored. Slides were labeled, boxed and delivered with all work sheets to the pathologist for examination. Two slides were prepared from each fish. Tissues processed and examined included but were not limited to; gill, thymus, liver, spleen, heart, gonad, kidney, foregut, hindgut, olfactory mucosa (nares), brain, ear, skin, muscle, pancreas and pharyngeal mucosa. RESULTS A summary of the examination of each fish is reported in Table 1. Only those tissues which were missing or contained demonstrable change are listed. The only tissue changes observed were hyperplasia of gill lamellar epithilium and fatty change of the liver. These changes were judged to be minimal and consistent with changes seen routinely in healthy fish. Autolipis of gill tissue was observed in several fish. This change was probably due to the poor penetration of the buffered formalin to the pos terior dorsal portion of the gill space. 603775 3 Based on these data, it is concluded that 30 days exposure to a nominal 78.01 concentration of 20 ug/)l did not cause any significant, demonstrable, tissue changes in 30 day old fathead minnow fry. ) ) G03776 ) Table 1 -- Histopathological examination of fathead minnow (Pimephales promelas) exposed 30 days to 100 mg/Z nominal 78.03 and control water. 100 mg/% 78.03 Fish # 1 2 3 4 5 6 Sex Ukna Ukn Ukn Ukn Fb F 7F 8 9 10 J F Ukn F Organ Condition Missing Tissue Normal Spleen, gonad, nares, ear Normal Spleen, gonad, thymus Normal Heart, gonad, nares Normal Spleen, gonad, thymus Normal Spleen, nares Liver-Fatty change ic Gill-Hyperplasia (epithelium) I Nares, thymus Liver-Fatty change I Gill-Hyperplasia (epithelium) 1 Nares, ear Liver-Fatty change I Spleen, ear Liver-Fatty change I Spleen, gonad, nares, ear Liver-Fatty change I Spleen, nares C03777 Table 1 (cont.) Fish # Control 1 Sex Ukn 2 Ukn 3F 4F 5 MMd 6F 7 Ukn 8 Ukn 9F 10 Ukn a Female. b Unknown. c Lesions are minimal. d Male Organ Condition Missing Tissue Liver-Fatty Gonad, nares, change I ! thymus Gill-hyperplasia , (epithelium) I Liver-Fatty change I Spleen, gonad, nares Gill-hyperplasia Thymus (epithelium) I Normal Spleen, nares Normal Spleen, thymus heart Liver-Fatty change I Spleen, heart Liver-Fatty change X Spleen, heart, gonad, thymus, nares Liver-Fatty change I Spleen, gonad, nares, thymus Liver-Fatty change I Gill hyperplasia (epithelium) I Spleen, nares Normal Gonad, thymus CQ3778 .. t l ) SUBMITTED BY: PREPARED BY: ) APPROVED BY E G & G, Bionomics Aquatic Toxicology Laboratory 790 Main Street Wareham, Massachusetts September/ 1978 Stephen J. Ells 'mm Aqmuaaltic Toxicologist George A. Cary J 003779