Acute toxicity of a used chrome lignosulphonate drilling mud to several species of marine invertebrate

The acute toxicity of a used seawater chrome lignosulphonate drilling mud to several species of marine annelids, crustaceans and molluscs was evaluated. The medium density mud (13·4 lb/gal, 1·57 kg/litre) was composed primarily of seawater, bentonite clay, chrome lignosulphonate, lignite, sodium hydroxide and barium sulphate. The toxicity of four mud/seawater preparations was determined. These were the layered solids phase (LSP), the suspended solids phase (SSP), the unfiltered mud aqueous fraction (MAF) and the filtered mud aqueous fraction (FMAF). Four species each of marine annelids and bivalve molluscs and five species of marine crustaceans were evaluated. The median lethal concentration of the MAF (96-h LC₅₀) varied from 32 to > 100% MAF for the different species. The FMAF was slightly less toxic than the MAF. Adult polychaetes, Neanthes arenaceodentata and Ctenodrilus serratus, one-day old juveniles of opossum shrimp, Mysidopsis almyra, and four day zoeae of grass shrimp, Palaemonetes pugio, were the most sensitive to the MAF. Juvenile N. arenaceodentata, adult polychaetes, Ophryotrocha labronica, and three bivalve molluscs were highly tolerant to the MAF. The SSP preparation at concentrations of 10-20 ml/litre was toxic to post-larvae and juveniles of the commercial shrimp, Penaeus duorarum and P. aztecus, respectively. Exposure to the LSP preparation caused greater than 50% mortality amongst adult N. arenaceodentata, juvenile and adult coquina clams, Donax variabilis texasiana and adult scallops, Aequipecten amplicostatus. Other species tested were quite tolerant. A sublethal response observed was the inhibition of reproduction in the marine annelids, Dinophilus sp. and Ctenodrilus serratus. Toxicity of the mud aqueous fractions appeared to be due primarily to volatile soluble organic materials in the extract, whilst that of the SSP and LSP preparations appeared to be due to the smothering action of fine particulates in the mud. Based on the results of this investigation and published observations of solids concentrations in the water column during drilling mud discharge, it is concluded that discharge of a used chrome lignosulphonate drilling mud, such as that used in the present investigation, from offshore platforms is not likely to cause measureable damage to benthic, demersal or pelagic marine animals.     

Comparative toxicity of drilling muds: role of chromium and petroleum hydrocarbons

Samples of used drilling muds collected during the course of a single well drilling operation exhibited different degrees of acute toxicity to sheepshead minnows and grass shrimp. For moulting grass shrimp, Palaemonetes pugio, the 96-h LC₅₀'s were 360 to 14 560 ppm (μl/litre); many of these values were considerably lower than those reported from previous drilling mud assays. However, when some of the muds used in this study were tested on sheepshead minnows, Cyprinodon variegatus, the resulting 96-h LC₅₀'s (6300 to 100 000ppm) were well within the range of previously reported values.Although a number of the drilling mud samples had relatively high amounts of chromium due to the addition of sodium chromate, there was a low correlation between chromium concentration and toxicity. In only three drilling muds could chromium content alone account for the observed toxicities. Furthermore, chemical analyses revealed the presence of No. 2 fuel oil like petroleum hydrocarbons in the mud samples. Based on the results of toxicity tests with No. 2 fuel oil and the concentrations of oil present in the muds, the toxicity of the mud samples to grass shrimp appears to be largely attributable to the petroleum hydrocarbon content.     

Copper bioavailability to marine bivalves and shrimp: Relationship to cupric ion activity

Studies were performed to determine the effects of dissolved substances present in natural seawater and sediment on the bioavailability of added Cu⁺². Whole clams Macoma inquinata and shrimp, Pandalus danae, were exposed to four concentrations of Cu in a flow-through seawater system. Bioaccumulation of Cu was reduced in shrimp, Pandalus danae, clams, M. inquinata, and excised clam gills, Protothaca staminea, exposed to an aged, compared with an unaged, Cu-seawater solution. This is thought to be due to slow complexation of the Cu by dissolved substances present in natural seawater. In a static system, with added sediment, more than 50% of the added Cu⁺² became bound to the organic fraction of the sediment and was unavailable to suspension feeding clams, Protothaca staminea. In contrast, deposit feeding clams, Macoma inquinata, placed in the sediment approximately doubled in Cu body burden within two months.Complexed Cu appears to be less bioavailable than ionic Cu and hence measurements of ionic and weakly complexed Cu by differential pulse anodic stripping voltametry provide a better prediction of bioavailable Cu than conventional measurements of total Cu-seawater concentrations.     

The effects of used ferrochrome lignosulphonate drilling muds from a Santa Barbara channel oil well on the development of starfish embryos

The effects of water-soluble fractions (WSF) of thirteen used ferrochrome lignosulphonate muds on developing embryos of Patiria miniata were studied. The muds were collected during the drilling of a single slant well from Platform Hondo in the Santa Barbara Channel, California, at drilling depths of 4220 to 9858 ft. None of the embryos survived 48 hours' exposure in 25 % WSF of the muds (25,000 ppm mud added (v/v)). Significant reduction in growth and high abnormalities (up to 100%) were observed in the 15% WSF. In lesser concentrations the effects varied from significant reduction of growth, down to 0·5% for three muds, to significant enhancement of growth for several muds in some dilutions. The EC₅₀'s ranged from 5% to greater than 15% WSF. In the 5% WSF, decreased embryo growth was correlated with increasing Cr concentrations and possibly also with total organic carbon (TOC). Although experiments carried out with NaOH addition to simulate the strong alkalinity of the muds showed increased abnormalities and decreased embryo growth with increasing pH, in the chemically complex WSF (5% dilution) the opposite effect occurred. Dissociation of chrome lignosulphonate molecules from particulates may occur with increasing acidity and explain the relationship between pH and toxicity in dilute WSF. The results of these experiments are discussed in terms of the effects of dispersions of drilling muds in the oceanic environment. It is concluded that water column effects on organisms during the dumping of such muds are only likely within short distances of the discharge pipes of offshore drill rigs.     

Effects of hexavalent and trivalent chromium on the reproduction of Neanthes arenaceodentata (polychaeta)

This study compared the very different responses of the polychaete Neanthes arenaceodentata to chronic exposure of hexavalent (Cr VI) and trivalent (Cr III) chromium. The polychaetes were exposed to sublethal concentrations of Cr VI and Cr III for periods of 440 days (three generations) and 293 days (two generations), respectively. In the Cr VI test, polychaete reproduction ceased at 100 μg litre^?1, and the number of young produced was reduced at the 12·5 to 50 μg litre^?1 levels and above. However, polychaetes that lived in Cr III during the test showed no adverse effects in 50400 μg litre^?1.     

Effects of polynuclear aromatic hydrocarbons on fishes and shellfish: An overview of research in virginia

This paper discusses the following topics related to polynuclear aromatic hydrocarbon pollution in estuaries: (1) the use of oysters (Crassostrea virginica), hard clams (Mercenaria mercenaria) and brackish water clams (Rangia cuneata) in residue monitoring; (2) the effects of elevated PAH residues on oyster condition; (3) three years of field studies relating PAH sediment contamination to abnormalities in fishes; and (4) laboratory bioassays for effects and bioconcentration modeling. Oysters, hard clams and Rangia have been shown, from 3 years of field studies, to be good monitors of pollution inputs as one proceeds along salinity gradients from 25‰ to 0·5‰. Effects of increased body burdens of PAHs are shown by a lowering of the oysters' condition index, as measured by lipid levels. Fishes inhabiting the Elizabeth River, VA, which is highly contaminated with PAHs, have abnormalities (cataracts, skin lesions, abnormal fins, etc.). These abnormalities have higher incidence in regions of the river where the sediments are more heavily contaminated. Laboratory studies utilizing contaminated sediments have reproduced some of the abnormalities observed in the field. Bioconcentration of PAHs from sediments has been studied with oysters and hard clams. Oysters generally accumulate three times the body burdens of clams exposed to the same suspensions. A faster depuration rate (k₂) for clams appears to be responsible for the higher equilibrium body burden of oysters.     

Cadmium accumulation,distribution and elimination in the bivalve Macoma balthica: Neither metallothionein nor metallothionein-like proteins are involved

Accumulation and elimination of cadmium was investigated in the tellinid clam, Macoma balthica (L.). Accumulation of Cd was linear in soft tissues (0·35 μg g⁻¹ day⁻¹ dry weight) throughout a 29-day exposure period at 100 μg Cd litre⁻¹. Loss of Cd, measured after transfer of experimentally-contaminated clams to clean seawater, was exponential and relatively slow (biological half-time, 70 days). In contrast, Cd uptake onto the shell of Macoma was characteristic of saturation kinetics, indicative of physical adsorption processes. Amounts of Cd accumulated by the shell were low, and the elimination rate rapid (half-time, 7 days) compared with soft tissues.Gel chromatographic profiles of cytosol extracts from control and experimental groups of M. balthica revealed that most of the Cd was bound to high molecular weight ligands, an unusual feature in bivalve molluscs. Although the proportion of cytosolic Cd associated with very low molecular weight ligands is small (< 15%) this pool may be important in regulating Cd fluxes in Macoma during uptake and elimination phases. No evidence was found of metallothionein (or similar metal-binding protein) involvement in Cd accumulation and storage in either field or laboratory exposed clams.The metabolism of Cd in M. balthica is different from that reported for other bivalve groups in several respects. In particular, the relatively slow rate of Cd accumulation in Macoma may be an important adaptive advantage for survival in contaminated areas and may compensate for the absence of a recognised detoxifying (MT) system in this species.     

Bioaccumulation of chromium and its effects on reproduction in Neanthes arenaceodentata (polychaeta)

The levels of hexavalent chromium (Cr VI) that caused diminished reproductive ability in the polychaete Neanthes arenaceodentata were determined. Changes in numbers of offspring and time of spawning caused by Cr VI at 1 to 38 ug/litre during two generations of exposure (309 days) were measured. Time to spawning was unaffected but it was found that reductions in numbers of offsprings occurred at 16 to 38 μl/litre. Bioaccumulation of chromium was also measured and found to be proportional to exposure levels; however, a direct relationship between tissue concentration and reduced numbers of offspring could not be established.     

Changes in survivorship,behavior, and morphology in native soft‐shell clams induced by invasive green crab predators

Many studies on invasive species show reduced native densities, but few studies measure trait‐mediated effects as mechanisms for changes in native growth rates and population dynamics. Where native prey face invasive predators, mechanisms for phenotypic change include selective predation, or induced behavioral or morphological plasticity. Invasive green crabs, Carcinus maenas, have contributed to declines in native soft‐shell clams, Mya arenaria, in coastal New England, USA. We tested the hypothesis that clam ability to detect chemical cues from predators or damaged conspecifics would induce greater burrowing depth as a refuge from invasive crabs, and greater burrowing would require increased siphon growth. To determine how crab predation affected clam survivorship and phenotypic traits in the field, clams in exclosure, open, and crab enclosure plots were compared. Crab predation reduced clam density, and surviving clams were deeper and larger, with longer siphons. To determine whether the mechanism for these results was selective predation or induced plasticity, phenotypes were compared between clams exposed to chemical cues from crab predation and clams exposed to seawater in laboratory and field experiments. In response to crab predation cues, clams burrowed deeper, with longer siphons and greater siphon mass. Overall, crab predation removed clams with shorter siphons at shallow depths, and crab predation cues induced greater burrowing depths and longer siphons. Longer siphons and greater siphon mass of deeper clams suggests clams may allocate energy to siphon growth in response to crabs. By determining native behavior and morphological changes in response to an invasive predator, this study adds to our understanding of mechanisms for invasive impacts and illustrates the utility of measuring trait‐mediated effects to investigate predator–prey dynamics.     

Radioecological studies of activation products released from a nuclear power plant into the marine environment

The seaweeds Fucus vesiculosus, Fucus serratus, Ascophyllum nodosum and Cladophora glomerata and crustaceans of the Idothea and Gammarus families have proven to be excellent bioindicators for radioactive corrosion products released from a nuclear power plant into the marine environment. These bioindicators have been used to map the spatial and temporal distribution of the released radioactivity. The activity has been followed up to 150 km from the power plant, and the decrease in activity concentration C(z) in the bioindicators with distance z can be expressed by a power function C(z) = α. z^?1·4 where α is a constant.The variation with time of activity concentration very well reflects the amount of activity discharged from the power plant, with surprisingly good resolution in time.The bioindicators exhibit different uptake patterns of the radionuclides detected, and variations from summer to winter for the crustaceans Idothea, when compared to Fucus, has been found.     

A preliminary assessment of oxygen isotope fractionation and growth increment periodicity in the estuarine clam Rangia cuneata

Rangia cuneata is an upper estuarine clam common in the coastal regions of the Gulf of Mexico. Limited data exist regarding oxygen isotope fractionation and microstructural increment periodicity in this species. As these clams were recently identified as an invasive species in other regions, such data may be useful for environmental management purposes. Additionally, the shell of this clam is common in archeological middens, and thus may serve as a paleoenvironmental proxy. In order to assess these aspects of the species’ natural history, samples were collected from the upper Mobile Bay, Alabama, USA. A stable oxygen isotope profile was generated from one of these valves, and compared to growth increments seen in thin section. Time-series water temperature data from near the collection site were used to construct idealized models of oxygen isotope variation, assuming equilibrium fractionation, constant shell growth, and stable water δ¹⁸O values. Comparison of the modeled and measured data suggest the shell was precipitated in, or near oxygen isotope equilibrium with ambient water, and that the microstructural increments in the shell were precipitated in response to tidal cycles.     

Axial vibration analysis of the mud recovery line on deepwater riserless mud recovery drilling system

The series connection of multistage pumping module is the common concept of deepwater riserless mud recovery drilling system. In this system, the influence of the mass of pumping module on the vibration of mud recovery line cannot be ignored, and the lumped mass method has been utilized to discretize the mud recovery line. Based on the analysis of different boundary conditions, the paper establishes the axial forced vibration model of the mud recovery line considering the seawater damping, and the vibration model analysis provides the universal solution to the vibration model. An example of the two-stage pumping system has been used to analyze the dynamic response of mud recovery line under different excited frequencies. This paper has the important directive significance for the application of riserless mud recovery drilling technology in deepwater surface drilling.     

The rate of infill and colonization by invertebrates of borrow pits in the Wash (S.E. England)

The outer borrow pit had a volume of 458 000 m³ when excavated and was further increased (by 22 500 m³) by the erosion of a lagoon, but was completely infilled in 3·5 years. The rate of sedimentation in the outer borrow pit, though declining with time, was considerably greater than previously recorded rates for intertidal banks and probably accounted for the paucity of fauna in the pit until completely infilled. Poorly sorted, unconsolidated, anaerobic, clay and silt sediments initially accumulated in the outer pit with up to 5 cm liquid mud at the surface, but after 2 years the predominant fraction was fine sand. Only Nepthys hombergii became established in the outer borrow pit before the pit was completely infilled, when the other pre-excavation, dominant species returned. The expectation that Capitella capitata and oligochaete species (opportunistic, ‘pollution indicator’ species) would be the first colonizers was not realized, though the oligochaete, Tubificoides benedeni was the most abundant species in the more consolidated, sandier sediments in the inner borrow pit 4 years after its excavation. The density of invertebrates in the inner pit was greater than the surrounding mud flats and was a focus for birds feeding in the area. The outer borrow pit after complete infill also had higher desities of bird food species than before excavation but was rarely visited by birds.     

Combined effects of a parasite,QPX, and the harmful-alga,Prorocentrum minimum on northern quahogs,Mercenaria mercenaria

Northern quahogs, Mercenaria mercenaria (L.), frequently are infected with the parasite Quahog Parasite Unknown (QPX, Labyrintohomorpha, Thraustochytriales), which can cause morbidity and mortality of the quahogs. Possible interactions between this parasitic disease and exposure to the harmful dinoflagellate Prorocentrum minimum in M. mercenaria were studied experimentally. Quahogs from Massachusetts with variable intensity of QPX infection were exposed, under controlled laboratory conditions, to cultured P. minimum added to the natural plankton at a cell density equivalent to a natural bloom. After 5 days of exposure, individual clams were diagnosed histologically to assess prevalence and intensity of parasitic infection, as well as other pathological conditions. Further, cellular defense status of clams was evaluated by analyzing hemocyte parameters (morphological and functional) using flow-cytometry. Exposure of quahogs to P. minimum resulted in: a lower percentage of phagocytic hemocytes, higher production of reactive oxygen species (ROS), larger hemocyte size, more-numerous hemocytic aggregates, and increased numbers of hemocytes in gills accompanied by vacuolation and hyperplasia of the water-tubular epithelial cells of the gills. Quahogs had a low prevalence of QPX; by chance, the parasite was present only in quahogs exposed to P. minimum. Thus, the effect of QPX alone on the hemocyte parameters of quahogs could not be assessed in this experiment, but it was possible to assess different responses of infected versus non-infected quahogs to P. minimum. QPX-infected quahogs exposed to P. minimum had repressed percentage of phagocytic hemocytes, consistent with immuno-modulating effect of P. minimum upon several molluscan species, as well as smaller hemocytes and increased hemocyte infiltration throughout the soft tissues. This experiment demonstrates the importance of considering interactive effects of different factors on the immunology and histopathology of bivalve shellfish, and highlights the importance of considering the presence of parasites when bivalves are subjected to harmful-algal blooms.     

Clam community composition and prey shell size impacts moon snail (Gastropod: Naticidae) drilling frequencies in South Carolina,USA

Moon snail predation on clams is a common model system of predator–prey interactions. In this system, the predator bores through the shell of its prey, leaving a distinct and identifiable hole. Some paleoecological and behavioral research on moon snails suggests a trend in predation preference directed toward clams with small shells. Rarely, however, have studies tested relative drilling frequencies across species and size ranges in natural assemblages of clam communities. We examined the clam community composition at two beaches in South Carolina, USA, and we then tested moon snail predator preferences for (a) clam prey species and (b) whether their selection is related to prey shell size. We collected a total of 1,879 clam shells, identified each shell to species and recorded their anteroposterior length. The species composition of clams differed significantly between the two beaches; Anadara ovalis was dominant at both sites, but three of ten total species were only collected at one beach. Folly Beach had nearly a 60% higher the overall drilling frequency (34.6%) versus Edisto Beach (21.8%), and this may be linked to the differences in clam community compositions at the sites. For A. ovalis and Mulinia lateralis, shells with larger lengths have lower probabilities of being bored by a moon snail. Anadara brasiliana, which generally is a thinner‐shelled clam species, had the highest total drilling frequency (77.2%), and Noetia ponderosa, a thicker‐shelled clam, had a considerably lower drilling frequency (12.0%). We conclude that both community level factors (species composition) and population characteristics (shell size distributions) may influence the local drilling frequency by moon snails.     

Histopathologic biomarker response of clam, <Emphasis Type="Italic">Ruditapes decussates</Emphasis>, to organophosphorous pesticides reldan and roundup: A laboratory study

Clam Ruditapes decussates was used as a biomonitoring organism to measure the potential impact of pollution. The present study investigated histological alterations of R. decussates following a long-term exposure to a sublethal-level of pesticides Reldan and Roundup. The clams were taken to the laboratory and kept for days to adjust to a continuous closed flow system with quality water control. After the adjustment period, clams were exposed either to sublethal concentrations of Reldan (0.6 μl L^?1) or Roundup (1.1 μl L^?1) for 90 days. Clams were taken to determine the histological damage at 30, 60 and 90 days. Most histological alterations were highly localized in the glandular cells of the gills, mantle tissues and digestive gland; secretions of glandular cells were found to be increased by increasing the time of exposure. Histopathological results showed the activation of resistance mechanisms that allowed the clams to survive under sublethal stresses. Thus, histological changes on localized tissues were sensitive and they have positive correlation to the time of exposure to the pesticides, suggesting that they may serve as biomarkers for Reldan and Roundup exposures.     

CHROMIUM DISTRIBUTION AND TRANSFER IN SEAWATER OF BOHAI GULF

The concentrations of dissolved chromium in seawater of the Bohai Gulf vary from trace to 1.6 μg /1 while those of particulate chromium from trace to 8.66 μg/1, indicating that the concentration of chromium in seawater of nearshore and estuary in the Bohai Gulf is higher than that of offshore, and reflecting the effects of estuarine and terrestrial pollutions. Observation data indicate that there is a positive correlation between particulate chromium and COD.The result shows that organic matter in seawater has a strong ability to combine chromium. When particulate chromium meets with seawater in estuary, it gradually settles down to sea-bottom sediments. Ratio of particulate chromium to total chromium in the Bohai Gulf yields a higher value, exceeding 90% in estuarine area, i.e. particulate chromium is a predominant form in seawater of the Bohai Gulf.     

LPS胁迫下五个群体菲律宾蛤仔TYR基因在鳃和肝胰腺中表达特性研究

为了解TYR基因与蛤仔免疫的关系,本实验利用荧光定量PCR技术研究了菲律宾蛤仔五个群体(白蛤、白斑马蛤、斑马蛤、养殖和野生群体)的鳃组织和肝胰腺组织在LPS胁迫下TYR基因在不同时间(0 h、3 h、12 h、24 h、48 h)的表达特性。结果表明,在LPS注射后鳃组织中TYR6基因表达水平在白蛤和白斑马蛤3 h、6 h、12 h,野生蛤仔3 h,斑马蛤3 h、6 h,养殖群体6 h、12 h显著上调(P<0.05),3h野生蛤仔和斑马蛤达到峰值, 6 h白蛤、白斑马蛤、养殖群体达到峰值(P<0.05);在肝胰腺中,养殖群体和白斑马蛤6 h,白蛤6 h、24 h,野生群体24 h,斑马蛤3 h显著上调, 3 h野生蛤仔和斑马蛤达到峰值,6h养殖群体、白蛤、白斑马达到峰值(P<0.05);鳃组织中TYR10基因表达水平在白蛤、野生群体和白斑马蛤3 h,养殖群体3 h、6 h,斑马蛤3 h、12 h显著上调(P<0.05),肝胰腺组织中TYR10基因表达水平在白蛤3 h,野生群体3 h、6 h、12 h,斑马蛤、养殖群体6 h显著上调(P<0.05),推测T...     

The present-day condition and regularities of the distribution of the bottom communities in Taganrog Bay

Six benthic communities (Oligochaeta, Neanthes, Hypanis, Dreissena, Chironomidae, and Cerastoderma) were distinguished in Taganrog Bay. The main factors influencing the distribution of the benthic communities in Taganrog Bay in 2003 are the salinity, the character of the sediment, and the origin of the fauna.     

Disruption of magnesium regulation in the crab Cancer productus exposed to chlorinated seawater

Exposure of the crab Cancer productus to chlorinated seawater resulted in alterations in haemolymph sodium and magnesium concentrations. At the highest chlorination levels, which approached the 96-h LC₅₀, regulation of both ions was essentially abolished. Reciprocal changes in the sodium and magnesium levels suggested an effect on the activity of the bladder wall, which has been implicated in the regulation of haemolymph magnesium in crustaceans.Additionally, exposure to 1·19 μg/ml applied Cl (0·68 μg/ml TRO) for 96 h resulted in a fourfold increase in the ammonia excretion rate. Crabs also contributed considerable chlorine demand to the exposure seawater. Measurements of TRO in the inhalant seawater and water exiting the crabs' branchial chambers indicated a reduction in TRO equivalent to 57% of that initially present in the inhalant water (0·51 μg/ml TRO).Measurements of ammonia concentrations in the exposure water indicated that ammonia in seawater was consumed in reactions with oxidants. This was especially evident at higher levels of chlorination. At 0·58 μg/ml applied Cl and above, chlorination resulted in near disappearance of ammonia from the water.