Uptake and Dupuration of Petroleum Hydrocarbons By the Backwater Clam,Meretrix Casta Chemnitz

Meretrix casta were experimentally exposed to water soluble fractions of refined and crude oil and their rate of accumulation of the petroleum hydrocarbons including total and individual aromatics viz., naphthalene, methylnaphthalene and dimethylnaphthalene, was studied. Subsequent transfer to clean waters in the laboratory and field resulted in depuration of the accumulated hydrocarbons from tissues. in general, the rate of discharge was found to be dependent on the concentration that the animals had been earlier exposed to and also the alkylation of aromatic hydrocarbons. Occasional increases were observed in the hydrocarbon values of clams which were placed in the field, compared to their laboratory counterparts, suggesting an intermittent source of petroleum hydrocarbon input into the environment. the influence on the rate of uptake, release and retention of hydrocarbons in the clams is discussed.     

植物-微生物修复石油烃污染土壤与根际微生态环境变化

石油烃作为一类持久性难降解有机污染物对土壤环境质量产生严重的危害。以天津大港油田原油污染土壤中筛选出的耐低温高效石油烃降解菌为靶细胞,以小麦、紫花苜蓿作为供试植物,利用盆栽试验,对植物-外源菌协同修复体系中的脱氢酶活性和土壤微生物多样性进行研究,分析其变化及其与石油烃降解率的关系。结果表明植物-微生物协同修复对石油烃具有较好的降解能力,其中小麦-固定化外源菌组具有最高的降解率,石油烃含量从最初的30 600 mg獉kg-1下降为24 300 mg獉kg-1,降解率为20.6%,并且其试验后期石油烃的降解率最大,远远高于其他时期,表现出良好的修复潜力。外源菌投加的初始阶段会迅速提高脱氢酶活性,然而这种影响随着降解时间延长而逐渐减弱。初期脱氢酶活性与总石油烃的降解存在较好的相关性,脱氢酶活性可以在一定程度上表征土壤石油烃的降解情况。微生物多样性与总石油烃降解也存在一定的相关性。     

The persistence of chronically accumulated hydrocarbons in the hard shell clam Mercenaria mercenaria

Hard shell clams, Mercenaria mercenaria, from the chronically polluted environment of the Providence River, USA, were transferred to a clean laboratory system located in lower Narragansett Bay, Rhode Island. The hydrocarbon contents of these transplanted clams were monitored for 120 days after transfer. After this period only slight depuration had occurred. A 41.9 g g wet weight^-1 average initial hydrocarbon burden decreased to 29.3 g g^-1, a decrease that became statistically significant (P<0.1) only after 120 days. At most, only 30% of the clams' hydrocarbons were lost. These findings indicate that the duration of the exposure period and the chemical nature of the source hydrocarbons are both instrumental in determining the persistence of these compounds in filter-feeding bivalves. Chronically accumulated petroleum hydrocarbons are strongly retained by the organisms and are only very slowly depurated.     

Accumulation,release and retention of petroleum hydrocarbons by the oyster Crassostrea virginica

Two Crassostrea virginica populations, differing in fat content, were experimentally exposed to a complex petroleum-hydrocarbon fraction. The hydrocarbons in this mixture were accumulated by both groups of oysters, and their lipid content, as well as the concentration of hydrocarbon in the water, were found to affect the rate and extent of accumulation. Hydrocarbons accumulated were rapidly, although incompletely, discharged when the oysters were transferred to an uncontaminated system. Amounts of hydrocarbons discharged and amounts retained after discharge are probably related to the level of contamination. The data can be interpreted as indicating that equilibration and the occurrence of multiple compartments where hydrocarbons can reside are factors involved in the uptake and retention of nonbiogenic hydrocarbons by oysters. The petroleum hydrocarbons contained in the oysters differed from the contaminating oil by displaying a greater aromatic content. In addition, gas-liquid chromatograms of aliphatic fractions of the hydrocarbons in the oysters rapidly showed a degraded appearance; the possibility that the oysters themselves are modifying the oil cannot be excluded.Contribution No. 3098 from the Woods Hole Oceanographic Institution.     

石油烃对栉孔扇贝血淋巴细胞DNA损伤的初步研究

为研究石油烃对海洋生物的毒性效应,将栉孔扇贝(Chlamys farreri)暴露于0.08、0.21和0.88mg·L-1石油烃中,采用单细胞凝胶电泳实验(彗星实验)技术检测不同暴露时间扇贝血淋巴细胞的DNA损伤程度,对照组中石油烃背景浓度为0.04mg·L-1。结果显示,低浓度(0.08mg·L-1)的石油烃短期(<7d)内即可导致栉孔扇贝血淋巴细胞的DNA损伤,并且随石油烃浓度的增大和暴露时间的延长,DNA损伤程度增加,石油烃浓度达0.88mg·L-1时,DNA损伤程度已非常严重。3d恢复实验后,各浓度组DNA损伤又均有不同程度的恢复。研究表明,彗星实验是检测石油烃对海洋贝类DNA损伤的一种有效手段,贝类血淋巴细胞DNA损伤有望成为石油烃污染的一种生物标志物,用于海洋污染的早期预警监测。     

Siphon nipping facilitates lethal predation in the clam Mesodesma mactroides (Reeve, 1854) (Mollusca: Bivalva)

In soft sediment marine communities, fishes frequently bite off extended siphons of buried clams; the consequential shortening of the siphon is known to reduce burial depth of the clams, secondarily increasing their vulnerability to lethal excavating predators. In this study, siphon nipping on the yellow clam, Mesodesma mactroides, was simulated by removing the top 6.6–30% of siphons. This caused a burrow reduction in 25–75%, respectively, compared to control individuals with intact siphons, in field and laboratory trials. To examine subsequent consequences of reduced burial depth, we exposed nipped and intact clams to potential predators in the laboratory simulating the observed natural clam abundance. Artificially nipped clams were consumed twice as much as control clams. The present results suggest that sympatric croppers contribute to the stock recovery failure by facilitation of lethal predation and that re-seeding to increase the local abundance of M. mactroides should be an essential aspect of conservation efforts in South America.     

Clamming up: environmental forces diminish the perceptive ability of bivalve prey

The lethal and nonlethal impacts of predators in marine systems are often mediated via reciprocal detection of waterborne chemical signals between consumers and prey. Local flow environments can enhance or impair the chemoreception ability of consumers, but the effect of hydrodynamics on detection of predation risk by prey has not been investigated. Using clams as our model organism, we investigated two specific questions: (1) Can clams decrease their mortality by responding to predators? (2) Do fluid forces affect the ability of clams to detect approaching predators? Previous research has documented a decrease in clam feeding (pumping) in response to a neighboring predator. We determined the benefits of this behavior to survivorship by placing clams in the field with knobbed whelk or blue crab predators caged nearby and compared mortality between these clams and clams near a cage-only control. Significantly more clams survived in areas containing a caged predator, suggesting that predator-induced alterations in feeding reduce clam mortality in the field. We ascertained the effect of fluid forces on clam perception of predators in a laboratory flume by comparing the feeding (pumping) behavior of clams in response to crabs and whelks in flows of 3 and 11 cm/s. Clams pumped significantly less in the presence of predators, but their reaction to blue crabs diminished in the higher velocity flow, while their response to whelks remained constant in both flows. Thus, clam reactive distance to blue crabs was affected by fluid forces, but hydrodynamic effects on clam perceptive distance was predator specific. After predators were removed, clams exposed to whelks took significantly longer to resume feeding than those exposed to blue crabs. Our results suggest that prey perception of predators can be altered by physical forces. Prey detection of predators is the underlying mechanism for trait-mediated indirect interactions (TMIIs), and recent research has documented the importance of TMIIs to community structure. Since physical forces can influence prey perception, the prevalence of TMIIs in communities may, in part, be related to the sensory ability of prey, physical forces in the environment that impact sensory performance, and the type of predator detected.     

Effects of petroleum hydrocarbons on the cytochrome P450 content of the mollusc bivalveMytilus galloprovincialis

The cytochrome P₄₅₀, identified by the characteristic 450 nm spectral peak of its carbon monoxide complex, was detected in the hepatopancreatic microsomes ofMytilus galloprovincialis, collected from Ponteau (Bay of Fos, France) in 1982 and 1983. When mussels were exposed to a variety of petroleum hydrocarbons, the cytochrome P₄₅₀ content increased. It is shown that aromatic hydrocarbons are more effective than alkanes in inducing a high level of cytochrome P₄₅₀. The possible use of this haemoprotein in hydrocarbon pollutant detection is discussed.     

Bioremediation of highly contaminated oilfield soil: Bioaugmentation for enhancing aromatic compounds removal

This study evaluated the effectiveness of different amendments--including a commercial NPK fertilizer, a humic substance （HS）, an organic industrial waste （NovoGro）, and a yeast-bacteria consortium--in the remediation of highly contaminated （up to 6% of total petroleum hydrocarbons） oilfield soils. The concentrations of hydrocarbon, soil toxicity, physicochemical properties of the soil, microbial population numbers, enzyme activities and microbial community structures were examined during the 90-d incubation. The results showed that the greatest degradation of total petroleum hydro- carbons （TPH） was observed with the biostimulation using mixture of NPK, HS and NovoGro, a treatment scheme that enhanced both dehydrogenase and lipase activities in soil. Introduction of exogenous hydrocarbon-degrading bacteria （in addition to biostimulation with NPK, HS and NovoGro） had negligible effect on the removal of TPH, which was likely due to the competition between exogenous and autochthonous microorganisms. None- theless, the addition of exogenous yeast-bacteria consor- tium significantly enhanced the removal of the aromatic fraction of the petroleum hydrocarbons, thus detoxifying the soil. The effect of bioaugmentation on the removal of more recalcitrant petroleum hydrocarbon fraction was likely due to the synergistic effect of bacteria and fungi.     

石油污染土壤对蚯蚓的致死效应及回避行为的影响

土壤石油污染对生态系统和人类健康有严重影响,其毒害诊断和风险评价的研究日益受到重视。以赤子爱胜蚓(Eiseniafoetida)为受试生物,利用受石油污染的实际土壤,将高浓度污染的土壤与清洁土壤混合,配制成不同污染水平的石油污染土壤,通过直接暴露的方式,分别以蚯蚓急性毒性死亡率和回避反应作为测试终点,评价了石油污染土壤对蚯蚓的生态毒性。结果显示,石油烃污染土壤对蚯蚓的7d-LC50和14d-LC50分别为32.5和29.4g·kg-1,而土壤中石油烃的浓度为8.0g·kg-1时,蚯蚓即有明显回避反应(回避率达80%),前两者为后者的3.7～4.1倍。可见,与急性毒性实验的测试终点LC50相比,行为测试终点对石油烃的响应更灵敏。蚯蚓的回避反应可更加及时地反映出土壤受石油污染的状况,发挥更好的指示作用。     

Effects of exposure to sublethal concentrations of crude oil on the copepod Centropages hamatus

Female copepods of the species Centropages hamatus show decreased ingestion rates and decreased egg viability when exposed to crude oil/seawater dispersions having crude oil concentrations of 10–80 ppb. However, rates of egg production were not significantly affected by these exposure levels. In addition, we found no evidence for accumulation of petroleum hydrocarbons by copepods exposed to 200 ppb of South Louisiana crude oil. The results imply that biosynthetic pathways involved in oogenesis may be influenced by sublethal concentrations of crude oil or that petroleum hydrocarbons directly affect the viability of eggs. Recruitment into field populations of copepods could be severely reduced as a consequence of exposure to low levels of physically dispersed crude oil.     

A long-term study of the effects of water-soluble fractions of No. 2 fuel oil on the survival,development rate,and growth of the mud crab Rhithropanopeus harrisii

Mud crabs, Rhithropanopeus harrisii (Gould), were exposed continuously for 6 months after hatching to water-soluble fractions (WSF) of No. 2 fuel oil. Survival, growth and development rate were monitored during this time. The zoeal stages were the most sensitive to fuel oil. A 20% WSF (0.36 ppm total naphthalenes, 1.26 ppm total hydrocarbons) was acutely toxic to these stages. Of the zoeal stages, the first stage appeared to be the most sensitive. The combined duration of the 4 zoeal stages was significantly increased by increasing WSF exposure concentrations. The megalopa and crab stages were not particularly sensitive to continued petroleum hydrocarbon exposure, particularly when compared to zoeal stages. However, mean duration of the megalopa and first crab stages was significantly affected by oil exposure. Individuals which survived the highest exposure concentrations as larvae appeared to grow larger during the crab stages, so that at the end of 6 months comparably staged crabs were equal to or larger than both control crabs and those exposed to low WSF concentrations. Stage distributions at the end of 6 months showed no differences due to WSF exposure. Sex ratios, which could be determined at the end of 6 months, were approximately 1, indicating no sex-related differential sensitivity to WSF exposure, at least as larvae or juveniles. The data indicate that these crabs possess considerable ability to recover from the effects of chronic sublethal exposure to petroleum hydrocarbons. The most deleterious effects of oil pollution on this species may be due to its impact on larval recruitment into the adult population.     

Responses of Mytilus edulis on exposure to the water-accommodated fraction of North Sea oil

Individuals of Mytilus edulis L., collected from the Erme estuary (S.W. England) in 1978, were exposed to low concentrations (7 to 68 g l^-1) of the water-accommodated fraction (WAF) of North Sea crude oil. The pattern of accumulation of petroleum hydrocarbons in the body tissues was affected by the presence of algal food cells, the period of exposure, the hydrocarbon concentration in seawater, the type of body tissue and the nature of the hydrocarbon. Many physiological responses (e.g. rates of oxygen consumption, feeding, excretion, and scope for growth), cellular responses (e.g. lysosomal latency and digestive cell size) and biochemical responses (e.g. specific activities of several enzymes) were significantly altered by short-term (4 wk) and/or long-term (5 mo) exposure to WAF. Stress indices such as scope for growth and lysosomal latency were negatively correlated with tissue aromatic hydrocarbons.     

添加不同营养助剂对石油污染土壤生物修复的影响

实验室条件下研究NPK复合肥、诺沃肥和腐殖酸三种物质不同配比添加对石油污染土壤的生物修复效果.在60d的修复实验中,定期取样测定土壤含油量、总异养菌数、石油烃降解菌数和脱氢酶活性,并采用PCR-DGGE技术研究修复过程中微生物多样性变化.结果表明,NPK肥的添加和NPK肥-诺沃肥-腐殖酸复合添加能够提高土壤中微生物的数量、微生物多样性和脱氢酶活性.在含油量为84600mg.kg-1的土壤中,添加营养助剂的处理60d后石油烃降解率为31.3%—39.5%,不添加营养助剂的石油烃降解率仅为3.5%.NPK肥-诺沃肥-腐殖酸复合添加对石油烃的降解率要高于NPK肥的单独添加(高8%),其原因可能是诺沃肥-腐殖酸能够有效提高土著微生物的活性,增加微生物的多样性,增强石油烃的降解.     

Degradation rates of aged petroleum hydrocarbons are likely to be mass transfer dependent in the field

Evidence for on site biodegradation may be difficult to provide at heterogeneous sites without additional experiments in controlled laboratory conditions. In this study, microbial activities measured as CO₂ and CH₄ production were compared in situ, in intact soil cores and in bottle microcosms containing sieved soils. In addition, biodegradation rates were determined by measuring the decrease in petroleum hydrocarbon concentrations at 7°C in aerobic and anaerobic conditions. Elevated concentrations of CO₂ and CH₄ in the soil gas phase indicated that both the aerobic and anaerobic microbial activity potentials were high at the contaminated site. Aerobic and anaerobic microbial degradation rates in laboratory experiments of petroleum hydrocarbons were highest in soils from the most contaminated point and degradation in the aerobic and anaerobic microcosms was linear throughout the incubation, indicating mass-transfer-dependent degradation. Different results for microbial activity measurements were obtained in laboratory studies depending on pretreatment and size of the sample, even when the environmental conditions were mimicked. These differences may be related to differences in the gas exchange rates as well as in changes in the bioavailability of the contaminant in different analyses. When predicting by modeling the behavior of an aged contaminant it is relevant to adapt the models in use to correspond to conditions relevant at the contaminated sites. The variables used in the models should be based on data from the site and on experiments performed using the original aged contaminant without any additions.     

Accumulation of 14C-1-naphthalene by an oceanic and an estuarine copepod during long-term exposure to low-level concentrations

Accumulation of the bi-cyclic aromatic hydrocarbon ¹⁴C-1-naphthalene in adult female Calanus helgolandicus Claus and adult female Eurytemora affinis Poppe in sea water concentrations of hydrocarbon ranging from 0.2 to 992 g/l was studied during exposure periods of up to 15 days as part of an investigation of the possible effects on marine zooplankton of persistent exposure to low levels of petroleum hydrocarbons. With both species the body levels of radioactivity increased rapidly during the first few days of the exposure period, but after exposure for 7 to 8 days to sea water containing 50 g hydrocarbon/l an equilibrium condition was approached; in some experiments where E. affinis was exposed to 1.0 and 10 g hydrocarbon/l for 15 days there was no further increase in body levels of radioactivity after 7 to 8 days. Using a low concentration of hydrocarbon (1 g/l), the quantity of radioactivity accumulated after 10 days was found to be nearly fifty times greater in the smaller species, E. affinis, than in C. helgolandicus, when expressed in terms of body weight. After they had been exposed to the hydrocarbon for several days the copepods contained a considerable proportion of radioactivity that was no longer identifiable as naphthalene and was presumably present as metabolites. Radioactivity accumulated in the copepods after several days was rapidly lost after they were transferred to uncontaminated sea water: e.g. C. helgolandicus lost nearly 90% of its body level of radioactivity in 24 h. Thereafter the rate of loss was greatly reduced, and 5% of the original body level of radioactivity still remained in the copepods at the end of 11 days. Experiments on the breakdown of naphthalene added at low concentrations to sea water samples containing natural microbial populations indicated degradation rates of 0.1 to 0.2 g/l/24 h in oceanic water, and 2.6 g/l/24 h in inshore water samples. The results are discussed in terms of the possible transfer of hydrocarbon to a higher trophic level in areas subjected to constant low-level inputs of petroleum hydrocarbons.     

Physiological evaluation of naphthalene intoxication in the tropical acrid clam Anadara granosa

Changes in vital physiological activities — shell movements and burrowing behaviour, uptake and depuration, filtration and respiration — on exposure to sublethal concentrations of naphthalene (Nap) were investigated in the tropical arcid blood clam Anadara granosa L. from the Bombay coast in 1986. On exposure to ambient concentrations exceeding 5g Nap ml^-1, shell valves opened widely within the first hour of exposure. The compressed muscular foot was stretched vertically upwards with copious secretion of mucus, and did not exhibit any evidence of burrowing behaviour. Those exposed to 5g Nap ml^-1 regained their normal physiological activities on transfer to stressor-free medium, whereas those exposed to higher levels became intoxicated and narcotized. Bioaccumulation of Nap was dependent upon environmental concentration, increasing exponentially with time over a 9h exposure period. Further exposure, up to 96h, however, did not increase tissue levels substantially. About 65% of the total body burden of Nap was depurated within 3h of transfer to Nap-free medium. Rates of filtration and oxygen consumption were significantly reduced (ca 70%, p<0.001) compared to control clams. Percent inhibition in these physiological activities was dependent upon tissue and ambient concentrations of Nap. On transfer to pollutant-free medium, clams exhibited remarkable recovery. Rates of both filtration and oxygen consumption were gradually increased and restored to normal levels, as observed in controls. However, clams exposed to upper limits lost their ability to burrow back into the sedimentary bed, leaving them susceptable to predators. Furthermore, induction of anaerobiosis and disruption of osmotic balance on exposure to Nap together with aerial exposure at low-water periods and salinity changes, acted synergistically and proved detrimental. The rates of growth and mortality observed in the natural population of blood clams, harvested from the coastal waters off Bombay, have been explained in terms of the impact of petroleum and allied waste products released from petrochemical industries.     

Biological effects of oil on early development of the Baltic herring Clupea harengus membras

The effects of petroleum hydrocarbons from two crude oils and one fuel oil (No. 1) were studied on the ontogenic development of the Baltic herring Clupea harengus membras L. Herring eggs exposed to water-soluble fractions of the oils at the time of fertilization showed no decrease in numbers of fertilized eggs compared to eggs exposed 6 or 72 h after fertilization. During embryongenesis, treatment with 3.1 to 8.9 ppm or 3.3 to 11.9 ppm total oil hydrocarbons from light fuel oil and the two crude oils respectively, gave rise to alterations in embryonic activity, decreased heart rate, and premature or delayed hatching. Although many larvae hatched from eggs exposed to contaminated water (3.1 to 11.9 ppm total oil hydrocarbons), the majority of the (70 to 100%) were malformed or dead 1 day after hatching. Exposure of eggs to 5.4–5.8 ppm total oil hydrocarbons resulted in significantly (P<0.001) decreased lengths of the larvae. Increased temperature (from 9° to 14°C) aggravated the effects of the oils. The results are discussed in relation to the potential effects of oil spills and chronic oil pollution on fish eggs and larvae in the Baltic Sea.     

Blooms of surf-zone diatoms along the coast of the Olympic Peninsula,Washington. XI. Regeneration of ammonium in the surf environment by the Pacific razor clam Siliqua patula

A 20 month field study was conducted on ammonium excretion rates of the Pacific razor clam Siliqua patula Dixon along the beaches of Washington State, USA. Excretion rates of all those nutrients likely to be regenerated in sufficient quantity to affect surf diatom growth were measured; ammonium appeared to be the most important metabolite. Excretion of ammonium by razor clams far exceeded that by other beach fauna. Ammonium excretion rates of razor clams were positively correlated with shell length, but no correlation between ammonium excretion rate and water temperature was evident. This may be an artifact or may represent some degree of seasonal acclimation of the species to temperature. Weight-specific ammonium excretion rates were negatively related to clam size, indicating a possible large (and unknown) contribution of regenerated ammonium by smaller clams in their first year of growth; smaller clams were rarely captured during this study.Contribution No. 1048 from the Department of Oceanography, University of Washington, Seattle, Washington 98195, USA.     

Fate of petroleum hydrocarbons taken up from food and water by the blue crab Callinectes sapidus

Radiolabeled paraffinic and aromatic hydrocarbons, including benzopyrene, fluorene, naphthalene, methylnaphthalene, methylcholanthrene, hexadecane, heptadecane and dotriacontane, were taken up from food and water by the blue crab Callinectes sapidus. In 2 days, approximately 10% of the benzopyrene and fluorene were taken up from the water when their concentrations were 2.5 and 30 g/l, respectively. When given food with radiolabeled hydrocarbons, 2 to 10% of the hydrocarbons were assimilated by the carbs, with the remainder excreted. After uptake of hydrocarbon from water or food, a major pathway for the elimination of hydrocarbon and metabolites was through fecal material. All hydrocarbons used in the study were metabolized, with similar rates for both paraffinic and aromatic hydrocarbons. More than 50% of the radioactivity assimilated by the crabs was in the hepatopancreas, suggesting that the hepatopancreas was the site of hydrocarbon metabolism. Twenty-five days aftex exposure to radiolabeled hydrocarbons, radioactivity was found only in the hepatopancreas. The hepatopancreas contained highly polar hydrocarbon metabolites, including dihydroxy-compounds and their conjugates, while blood contained both monohydroxy-and dihydroxy-compounds. No evidence was found of storage of hydrocarbons by any of the crab tissues.