Toxicity of Drilling-Mud Biocides to Developing Estuarine Macrobenthic Communities

The effects of various blocides, as used in drilling muds for exploratory drilling for oil offshore, were determined by comparing macrobenthic communities that developed from planktonic larvae in treated and untreated aquaria. Surflo®-B33 and Aldacide® were tested simultaneously. Harvest at seven weeks yielded 1,941 animals, representing 37 species of 6 phyla. The etfects of Surflo-B33 (25% dichlorophenol and other chlorophenals) on these communities were similar to those of pentachlorophenol (Tagatz et al, 1977; 1978), a biocide known to be toxic to many aquatic organisms (Rao, 1978). Significantly fewer (a=0.05) chordates, mollusks, and annelids occurred in 819 µg Surflo-B33/l (measured) than in the control; mollusks were most sensitive and also significantly fewer in aquaria receiving 41 µg/l. Average numbers of animals and species per aquarium did not significantly decrease in Aldacide (91% paraformaldehyde) at nominal concentrations of 15 and 300 µg/l. The high toxicity of the chlorophenols tested indicates that use of alternative biocides, possibly paraformaldehyde, should be considered for natural waters

Impact on and Recovery of Experimental Macrobenthic Communities Exposed to Pentachlorophenol

Recovery of macrobenthic animal communities in sand-filled aquaria was deter· mined 7 weeks after a 5-week exposure to 55 μglℓ. pentachlorophenol. The communities developed from planktonic larvae in flowing estuarine water continuously supplied during treatment and recovery. Significantly fewer (α= 0.05) individuals and species occurred in contaminated aquaria than in control aquaria immediately after exposure to pentachlorophenol. Numbers of arthropods, chordates, echinoderms, and mollusks were decreased; annelids and coelenterates were not affected. Seven weeks after exposure was discontinued, total numbers of individuals and species in previously contaminated and control aquaria no longer differed. The dominant echinoderm, Leptosynapta inhaerens, reduced numerically in contaminated aquaria at 5 weeks, increased in number not significantly different from the control at 12 weeks. However, there were some differences among species in previously contaminated aquaria and the control that could be attributed to the toxicant. Numbers of Galathowenia sp., the dominant annelid at 12 weeks and not collected at 5 weeks, were lower in previously contaminated aquaria than in control aquaria. The dominant mollusk, Laevicardium mortoni, did not recover after it was reduced in abundance by exposure to PCP. Major differences in community structure between 5 and 12 weeks were not toxicant related, however, and possibly represent natural succession. These consisted of reduced numbers of amphipods, Corophium acherusicum, and tunicates, Molgula manhattensis, at 12 weeks in both control and previously contaminated aquaria

Effects of a Lignosulfonate-Type Drilling Mud on Development of Experimental Estuarine Macrobenthic Communities

Drilling mud, as used in exploratory drilling for oil offshore, affected the composition of estuarine communities that developed from planktonic larvae in aquaria containing sand and flowing estuarine water. Aquaria contained: sand only; a mixture (by volume) of 1 part mud and 10 parts sand; 1 part mud and 5 parts sand; or sand covered by 0.2 CIU mud. For all environments, annelids, mollusks, arthropods, and coelenterates were the numerically dominant phyla collected in a 1 mm mesh sieve after eift weeks exposure; a total of 1,025 animals, representing 45 species, was collected. Annelids and coelenterates were significantly fewer (a=0.05) in aquaria containing drilling mud than in the control aquaria. Arthropods were significantly affected only by mud cover over sand; mollusks also were diminished in this environment, but not significantly. Exposure to concentrations of drilling mud reduced not only the number of individuals, but also the frequency of occurrence of macrobenthic species. Thus, the average number of annelid species in 1 part mud: 5 parts sand aquaria or in mud-covered aquaria was significantly less than in control aquaria, The average number of arthropod species per aquarium was also significantly less in the mud-cover exposure than in the control. Discharge of large quantities of drilling mud at levels tested in the laboratory could adversely affect the colonization of various substrata by benthic animals in nature

COMPRENDO: Focus and approach

Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body’s signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult. A major concern is that some of these EDCs appear to be biologically active at extremely low concentrations. There is growing evidence to indicate that the guiding principle of traditional toxicology that “the dose makes the poison” may not always be the case because some EDCs do not induce the classical dose–response relationships. The European Union project COMPRENDO (Comparative Research on Endocrine Disrupters—Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds) therefore aims to develop an understanding of potential health problems posed by androgenic and antiandrogenic compounds (AACs) to wildlife and humans by focusing on the commonalities and differences in responses to AACs across the animal kingdom (from invertebrates to vertebrates)

Fishes of the St. Johns River, Florida

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