James M. Patrick

Kepone® bioconcentration, accumulation, loss, and transfer through estuarine food chains

Accumulation, transfer, and loss of Kepone in estuarine organisms were studied in laboratory bioassays. Kepone was bioconcentrated by oysters (Crassostrea virginica), mysids (Mysidopsis bahia), grass shrimp (Palaemonetes pugio), sheepshead minnows (Cyprinodon variegatus), and spot (Leiostomus xanthurus), from concentrations as low as 0.023 μg/l seawater. Bioconcentration factors ranged from 10 to 340 in static exposures and 900 to 13,500 in flow-through bioassays, and were dependent on species and exposure duration.

Waterborne and sediment-source toxicities of six organic chemicals to grass shrimp (Palaemonetes pugio) and amphioxus (Branchiostoma caribaeum).

Grass shrimp (Palaemonetes pugio) were exposed to either waterborne or sediment-source concentrations of fenvalerate, cypermethrin, 1,2,4-trichlorobenzene (TCB), tributyltin oxide (TBTO), triphenyltin oxide, and di-n-butylphthalate in static or flow-through test systems. Similarly, amphioxus (Branchiostoma caribaeum) were tested with fenvalerate, TCB, and TBTO. The LC50 and no-effect and 100% mortality concentrations are reported from 96-hr and 10-day tests. The toxicity of contaminated sediments could be explained by chemical partitioning into overlying or interstitial water. Amphioxus is not recommended as a routine test species because of (1) difficulty in distinguishing severely affected from dead individuals, (2) inability to determine the status of burrowed animals without disrupting sediment, (3) their relative lack of sensitivity in acute exposures to toxic chemicals, and (4) difficulty in routine collection of sufficient numbers of animals. Grass shrimp, however, are useful as an epibenthic test species for waterborne and sediment-source toxicants.

Acute Toxicity to and Bioconcentration of Endosulfan by Estuarine Animals

Acute (96-h) flow-through toxicity tests with endosulfan (Thiodan) were conducted with several estuarine animals. The test species and their 96-h lethal concentration for 50 percent of the organisms (LC 5 0 ) values were: pink shrimp (Penaeus duorarum), 0.04 μg/litre; grass shrimp (Palaemonetes pugio), 1.3 μg/litre; pinfish (Lagodon rhomboides), 0.3 μg/litre; spot (Leiostomus xanthurus), 0.09 μg/litre; and striped mullet (Mugil cephalus), 0.38 μg/litre. In a 56-day bioconcentration study (28-day uptake, 28-day depuration), striped mullet were exposed to 0.008 and 0.08 μg endosulfan/litre seawater. The two endosulfan isomers (endosulfan I and II) were rapidly metabolized to endosulfan sulfate; only trace amounts of each isomer were detected in edible tissue or offal of mullet exposed to 0.08 μg/litre (0.035 μg/litre measured) for 28 days. Maximum bioconcentration factors of endosulfan were 2249 in edible tissue and 2755 in whole-body analyses. After 48 h in pesticide-free seawater, endosulfan was not detected in the previously exposed mullet. Our studies suggest that endosulfan in the estuarine environment would be a hazard because of its acute toxicity and bioconcentration potential, but animals surviving exposure and moving to areas free of endosulfan would lose the chemical rapidly.

Comparative acute sensitivities of early life stages of atherinid fishes to chlorpyrifos and thiobencarb.

Sensitivity, expressed as the 96-hr LC50 derived from acute lethality tests, was compared for four ages (day-of-hatch, 7-day, 14-day, and 28-day) of three atherinid fishes:Leuresthes tenais (California grunion),Menidia menidia (Atlantic silverside), andMenidia peninsulae (tidewater silverside). Responses of each age-species combination exposed to the organophosphate insecticide chlorpyrifos and the carbamate herbicide thiobencarb were compared in both static and flowing seawater toxicity tests. Chlorpyrifos was highly toxic to all atherinids (96-hr LC50s ranged from 0.4 to 6.7 μg/ L); toxicity of thiobencarb was approximately two orders of magnitude lower (LC50 values from 199 to 1,405 μg/L). Responses to each pesticide were similar among the three species. Sensitivity was generally highest for 7-day and 14-day age groups, and flowing water tests were more sensitive measures of toxicity than static tests, especially for chlorpyrifos. Comparisons of three computational methods indicate that probit and moving average methods calculate comparable LC50 estimates with the binomial method being the least uniform point estimator.

Kepone®: Toxicity and bioaccumulation in blue crabs

Two long-term studies were conducted to determine toxicity, uptake and depuration of Kepone in blue crabs (Callinectes sapidus). In the first, Kepone was administered to crabs in seawater (0.03 or 0.3 μg Kepone/I) or food (eastern oyster,Crassostrea virginica, containing 0.25 μg/g Kepone). Uptake of Kepone in 28 days was primarily through the contaminated oysters. When these crabs were held in Kepone-free seawater and fed Kepone-free oysters for 28 days, no loss of the insecticide was evident. There were adverse effects on molting and survival in crabs fed oysters that contained 0.25 μg/g Kepone.A second study was conducted to determine: (1) the depuration of Kepone over a 90-day period in blue crabs fed oysters from the James River, Virginia (containing 0.15 μg/g Kepone); and (2) the effects of Kepone on molting and survival of blue crabs fed James River oysters or laboratory-contaminated oysters that contained 0.15 or 1.9 μg/g Kepone. Crabs fed Kepone-contaminated oysters followed by a diet of Kepone-free oysters for 90 days had detectable concentrations of the insecticide in tissues. Also, blue crabs that ate oysters containing Kepone in concentrations similar to those found in oysters from the James River, died or molted less frequently than crabs fed Kepone-free oysters meats.

Uptake and toxicity of toxaphene in several estuarine organisms.

The organochlorine insecticide, toxaphene, was tested in flow-through bioassays to evaluate its toxicity to estuarine organisms. The organisms tested and their respective 96-hr LC5Os (based on measured concentrations) are: pink shrimp (Penaeus duorarum), 1.4Μg/L; grass shrimp (Palaemonetes pugio), 4.4Μg/L; sheepshead minnow (Cyprinodon variegatus), 1.1Μg/L; and pinfish (Lagodon rhomboides), 0.5Μg/L. Toxaphene concentration estimated to reduce shell deposition in American oysters (Crassostrea virginica) by 50% (EC50) was 16Μg/L. Concentration factors (concentration of toxaphene in tissues divided by concentration measured in water) for fishes and oysters in 96 hr ranged from 3,100 to 20,600 and for shrimp, from 400 to 1,200.Individuals from various ontogenetic stages of longnose killifish (Fundulus similis) were exposed to toxaphene for 28 days in flow-through bioassays. Toxaphene was toxic to embryos, fry, juveniles, and adult fish, but fertilization of ova in static tests was not affected by the concentrations tested (0.32 to 10Μg/L). The 28-day measured LC50s for all stages ranged from 0.9 to 1.4Μg/L. Toxaphene was accumulated in ova and other body tissues of the longnose killifish; concentration factors in ova were 1,000 to 5,500, and in whole-body tissues, 4,200 to 60,000.

THE EFFECTS OF URBANIZATION ON THE CHEMICAL QUALITY OF THREE TIDAL BAYOUS IN THE GULF OF MEXICO

Water and sediment quality in threetidal bayous located near Pensacola, Florida, wereassessed during 1993–1995. The primary objective wasto determine the environmental condition of therelatively small urban bayous by comparing thechemical quality of the sediments and surface waterwith published guidelines and criteria developed toprotect marine life. Surface water concentrations ofmost potential toxicants such as heavy metals,organochloride pesticides, PAHs and PCBs were usuallybelow method detection limits. The major exception tothis trend was for copper which consistently exceededFlorida and National acute and chronic water qualitycriteria. Nickel, cadmium and chromium intermittentlyexceeded these criteria. Sediment contamination wassite-specific and chemically diverse. Theconcentrations of as many as 17 compounds exceededproposed Florida sediment quality assessmentguidelines indicating the potential for adversebiological effects. Nutrient concentrations, with oneexception, were below average levels found in otherFlorida estuaries. Seasonal variation in contaminantconcentrations for sediment collected from the samesampling station was less than an order of magnitude. The differences in the concentrations of the sameanalytes as measured for the multiple samplingstations located within the same bayou varied 1 to 2orders of magnitude and over 2 orders of magnitude forthe 20 sampling stations located in the three bayous. A within-bayou sediment contaminant gradient wasevident; sediment quality generally improved seaward.

Effects of Sodium Pentachlorophenate on Several Estuarine Animals: Toxicity, Uptake, and Depuration

Several estuarine animals were exposed to sodium pentachlorophenate (Na-PCP), in flow-through toxicity tests. The following are test animals and their 96-hr LC50 values: grass shrimp (Palaemonetes pugio), > 515 μg/l brown shrimp (Penaeus aztecus), > 195 μg/1; longnose killifish (Fundulus similis), > 306 μg/1; pinfish (Lagodon rhomboides), 53.2 μg/1; and striped mullet (Mugil cephalus), 112 μg/1. The 192-hr EC50 (effect measured was shell deposition) for the eastern oyster (Crassostrea virginica) was 76.5 μg/1.

Periphyton and Sediment Bioassessment in North Florida Bay

Periphyton colonization and sediment bioassessment were used ina survey to compare the relative environmental condition ofsampling sites located in Florida Bay and four peripheral sloughareas during the summer of 1995. Periphyton biomass, pigmentcontent, tissue quality and community composition weredetermined. In addition, benthic community composition and thetoxicities of whole sediments and associated pore waters weredetermined for two species of rooted macrophytes, an epibenthicinvertebrate and bioluminescent bacteria. Several locational differences were observed for the response parameters.Periphyton biomass was significantly greater in the Taylor Riverand the least in Shell Creek (P < 0.05). Most sediments were notacutely toxic to mysid shrimp nor phytotoxic. However, sedimentsfrom the Taylor River were more phytostimulatory than others (P< 0.05). Contaminant bioresidues were similar at most sites,however, mercury, chromium and nickel concentrations weregreater for periphyton colonized in the Taylor River and TroutCreek areas. Structural characteristics of the periphytic algalcommunity usually were statistically similar but a consistenttrend of lower density and diversity was evident for ShellCreek. The benthic community was the least diverse and dense inthe Canal C-111. The results of this study provide an initialindication of differences in the role of several slough areas aspossible sources of bioavailable contaminants to Florida Baywhich warrants additional investigation.

Accumulation of sediment-bound PCBs by fiddler crabs

The primary objective of this research was to characterize rates of PCB uptake and depuration by fiddler crabs in a simulated spoil bank habitat that contained PCBs in weathered sediment. Also, the authors examined whether the concentration of PCBs in substrates affected bioaccumulation by mixing PCB-laden sediments with clean sand. In a pilot study, they tested Uca pugilator, an inhabitant of relatively dry and sandy areas, and U. minax, which inhabits wetter and muddier substrates, to determine if species differ in PCB uptake and depuration rates.