Document 1Qpz7kpJZ8ER3VBgvXMreQk95

AR 226-035 SUMMARY OF HISTOPATHOLOGICAL EXAMINATIONS OF FATHEAD MINNOW (Pimephales promelas) EXPOSED TO 78.01 FOR 30 DAYS. p M - 3 V'Z"*-' RESEARCH REPORT SUBMITTED TO 3M COMPANY ST. PAUL, MINNESOTA i.i REPORT #BW-78-9-300 SUBMITTED BY E G & G, Bionomics Aquatic Toxicology Laboratory 790 Main Street Wareham, Massachusetts September, 1978 006410 INTRODUCTION An "egg and fry test" was conducted between March 31 and May 4, 1978 (Bionomics Report #BW-78-6-195., June, 1978) to assess the sub-lethal effects of 78.01 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 78.01, 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 78.01 concentration (20 ug/, nominal) were preserved in 10% buffered formalin and s e n t ... to the Environmental Pathology Laboratories, Inc. Carolina, Rhode Island. Control fish from a similar ongoing study were also examined. i The fish were examined for gross lesions, and sagital sections were prepared by a pathologist. Fish were placed with identi fying 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 006411 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 \y Table 1. Only those tissues which were missing or contained demonstrable change are listed. i 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 x^ith 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. 006412 3 Based on these data, it is concluded that 30 days exposure to a nominal 78.03 concentration of 100 mg/Z did not cause any significant, demonstrable, tissue changes in 30 day old fathead minnow fry. 006413 Table 1 -- Histopathological examination of fathead minnow (Pimephales promelas) exposed 30 days to 20 ug/2. nominal 78.01 and control water. 20 uq/ 78.01 Fish # 1 2 3 4 5 6 7 8 9 10 Control 1 2 , 3 4 Sex Fa Uknb Ukn Ukn F F F F F F Ukn Ukn F F Organ Condition Missing Tissue Normal Ear, thymus Normal Normal Normal Spleen, gonad nares ' Spleen, gonad, thymus Spleen, heart, gonad, nares Normal Spleen, nares . Normal Spleen, nares, thymus Normal Spleen, heart. Normal Normal Spleen, heart, nares Spleen Gill Hyperplasia Spleen, heart, (epithelium) Ic thymus i Liver-fatty change I Gill-hyperplasia (epithilium) I Gonad, nares, thymus Liver-fatty change I Spleen, gonad, nares Gill-hyperplasia Thymus (epithilium) I Normal Spleen, nares 006414 Table 1 (cont.) Fish # Control 5 6 7 8 9 Sex Md F Ukn Ukn F 10 Ukn a Female. b Unknown. c Lesions are minimal, d Male Organ Condition Missing Tissue Normal Liver-fatty change I Spleen, thymus heart Spleen, heart Liver-fatty change I Liver-fatty change I Spleen, heart, gon ad, thymus, nares Spleen, gonad, nares, thymus Liver-fatty change I Gill hyperplasia (epithelium) I Spleen, nares Normal Gonad, thymus V 006415 SUBMITTED BY: PREPARED BY: APPROVED BY: E G & G, Bionomics Aquatic Toxicology Laboratory 790 Main Street Wareham, Massachusetts September, 1978 Stephen J. Ells oxicologist George A. Cary V 006416