Cytological and Physiological Biomarker Responses from Green Mussels, Perna viridis (L.) Transplanted to Contaminated Sites in Hong Kong Coastal Waters

Biological monitoring of marine contaminants often involves the analysis of metals accumulated in mussel tissues. Critiques of this type of monitoring suggest that although relatively good indications of ambient metal concentrations are determined, actual biological harm is not elucidated. Biomarkers, techniques originally developed in medicine, have recently been employed in an attempt to ascertain the health of marine mussels. Biomarkers have been used with good effect in temperate marine pollution monitoring programmes. The use of biomarkers in the toxicological evaluation of tropical and subtropical waters is, however, generally lacking, which is somewhat surprising, as considerable industrialisation and environmental degradation is taking place in the Pacific-rim countries of Southeast Asia. In the present study, a suite of cytological and physiological biomarkers have been measured from mussels (Perna viridis: Mytilidae) transplanted within the coastal waters of Hong Kong. Mussels from contaminated sites, had labile lysosomal membranes, whereas animals from a cleaner reference site had more stable membranes. These cytological responses have been related to metal-induced stress and are simple, cost-effective markers of pollution. Cardiac activity from mussels transplanted to polluted sites was generally similar to that of individuals from the reference site, although a mild tachycardia was associated with one site. The cause of the tachycardia and the use of heart rate in mussels as a biomarker is discussed. Integrated physiological responses to stress, condition indices, revealed mussels from a clean reference site had higher indices than animals from contaminated sites. The relative sensitivities of the cytological and physiological biomarkers deployed in this study and their application to pollution monitoring is discussed.     

A new sentinel organism for vanadium and titanium

Using X-ray Energy Spectroscopy trace metal concentrations (Ti, V, Mn, Fe, Ni, Cu, Zn, As, Pb) were measured in specimens of Eudistylia vancouveri (feather duster tube worms) collected from floating wharves near and far from a storm water outfall in a metropolitan area. As for the well-studied bio-accumulator Mytilus edulis (mussels), higher metal concentrations were noted in specimens near the pollution source. In particular the worms accumulated certain metals, namely vanadium and titanium, not picked up by the mussels, signaling that a new sentinel organism could be available.     

Mercury pollution in the waters around Harboøre Tange and Limfjord,Denmark

High concentrations of mercury have been measured in mussels (Mytilus edulis) collected in two ‘hot spot’ areas: (1) near a closed-down chemical factory on the west coast of the Limfjord, and (2) on groynes in the immediate vicinity of a chemical deposit in the dunes on the Danish west coast. By collecting comparable samples of mussels from chains of buoys, the mercury pollution in the western Limfjord could be traced 50–100 km into the central and innermost parts of the Limfjord as a gradual decreasing mercury concentration gradient. By collecting mussels from groynes north and south of the chemical deposit, it was possible to monitor the relative extent of the mercury leakage to the North Sea before and after the excavation of the deposit. The investigations have demonstrated the applicability of M. edulis as a monitoring organism for mercury when importance is attached to concentration gradients and distribution patterns in well defined and homogeneous samples of mussels collected from natural populations.     

基于"标准化"背角无齿蚌(Anodonta woodiana)对太湖五里湖重金属污染的主动监测

将人工繁育的"标准化"背角无齿蚌(Anodonta woodiana)移殖至太湖五里湖,并以仍养殖在未受污染的中国水产科学研究院淡水渔业研究中心南泉基地的同批蚌作为对照,进行为期9个月的主动监测研究.每3个月回收一次蚌样,应用电感耦合等离子质谱仪(ICP-MS)测定15种重金属(Al、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ag、Cd、Ba、Tl和Pb)的含量.结果表明,南泉基地对照组和五里湖移殖组的蚌样对重金属均产生了明显的生物积累.培养3个月的五里湖移殖组蚌样中As的含量显著高于同期南泉基地对照组,而前者Mn、Fe、Zn和Ba含量显著低于后者;培养6个月的五里湖移殖组蚌样中Al和Pb的含量显著低于同期南泉基地对照组;培养9个月的五里湖移殖组蚌样中Pb含量显著低于同期南泉基地对照组.然而,南泉基地对照组和五里湖移殖组蚌样中重金属(Cr、Cu、As、Cd和Pb)含量均低于我国及国际上的相关标准.培养3、6和9个月的南泉基地对照组及五里湖移殖组蚌样的重金属污染指数分别为1.8、1.8,2.4、2.1和8.3、16.8,均值综合污染指数分别为0.0218、0.0289,0.0337、0.0218和0.0560、0.0732,属于正常背景水平,并且两水体蚌样的重金属污染指数和均值综合污染指数无显著差异,提示五里湖和南泉基地均未受到明显的重金属污染.     

The usefulness of transplantation studies in monitoring of metals in the marine environment: South African experience

Due to their close proximity to the point sources of pollution, estuaries and harbours are exposed to metals. Mussels are used worldwide to monitor marine pollution due to their ability to take up contaminants and the ease of transplantation. Mussels were collected from two reference sites and transplanted in Richards Bay Harbour (2006 and 2010) and in three harbours. Transplanted and resident mussels were removed after 6 weeks exposure and metal concentrations were analysed using ICP-MS techniques. Transplanted mussels had higher metal concentrations than the resident mussels. This was attributed to regulation of metals by the resident mussels. Metal regulation was greater in mussels that are continuously submerged as opposed to those that undergo tidal influences. For monitoring it is essential that the reference population for transplantation is considered carefully as upwelling events in the pristine reference location results in significant increases in metal bioaccumulation.     

The effects of depuration,size and sex on trace metal levels in bay mussels

The effects of depuration, size and sex on the concentrations of Mn, Ni, Cu, Zn and Cd were determined for gonadal and somatic tissues of Mytilus edulis from Yaquina Bay, Oregon. After depuration, Mn levels decreased significantly in both tissues while Cu and Ni concentrations increased in somatic tissues. The latter finding may have been associated with a stress response manifested by the appearance of new byssal threads and attachment to the vessel. Larger, and presumably older, mussels contained higher concentrations of Ni, Cu and Cd in their somatic tissues while smaller animals had greater somatic levels of Mn. There were no significant differences in gonad concentrations between the two size groups. Manganese and Zn levels were greater in the gonads of female mussels and Cd was more concentrated in the somatic tissues of females.     

Cellular energy allocation in mussels (Mytilus galloprovincialis) from the stratified estuary as a physiological biomarker

This study demonstrates the usefulness of cellular energy allocation (CEA) evaluations as a physiological biomarker to infer the occurrence of natural stress in native populations of mussels inhabiting the stratified estuary (Krka River estuary, Croatia). Sampling sites were selected based on their differences in the salinity and temperature. The CEA value was calculated as a ratio between available energy (E_a) and energy consumption (E_c). Generally, higher values of E_a were recorded in June than in November, which were especially evident in the storage components (carbohydrates and lipids), while the constitutive component (proteins) remained relatively constant. The highest E_c was recorded in mussels at estuarine site compared to coastal site, which may be caused by the energetically costly maintenance of osmotic balance. Decrease in CEA recorded in estuarine mussels may ultimately result in a lower amount of energy available for growth, reproduction, or defence against other stresses (e.g. pollution).     

Application of artificial mussels (AMs) under South African marine conditions: A validation study

Over the last three decades there has been a significant decline in the number of marine pollution monitoring-related studies in South Africa. Thus, the current study was conducted to assess the current state of metal contamination within the South African marine environment through the validation of the artificial mussel (AM). Indigenous reference mussels (Perna perna) were deployed alongside the passive device within the South African marine environment for a 6 week exposure period. Analysis of metal uptake (Cd, Cr, Cu, Pb and Zn) was determined by filtration and elution of the AM chelex resins, microwave digestion of the transplanted mussels, and determination of their metal concentrations by ICP-MS and ICP-OES analysis. Uptake patterns between the AM and transplanted mussels showed significant temporal and spatial correlation for the majority of the elements analysed. While the AM provided relevant and complementary information on the dissolved metal concentrations, limitations were also observed.     

PCB-containing paint and plaster caused extreme PCB-concentrations in biota from the Sørfjord (Western Norway)--a case study

The Sørfjord (Western Norway) has a long history of industry and pollution, and has been monitored for several decades. The environmental monitoring has comprised analyses of different contaminants in sea water, mussel, fish, seaweed and sediments. Measurements of polychlorinated biphenyls (PCBs) in blue mussels (Mytilus edulis) some 17 years ago indicated a local source. In 2001 severe concentrations were measured in blue mussels and further investigations disclosed the primary source of PCBs in the Sørfjord. In 2002, extreme PCB-concentrations were found in cod (Gadus morhua) from the same area. However, no induction of EROD activity was detected, indicating the limitations of this assay as marker for PCB contamination. A future scientific challenge will be to understand the specific mechanisms and effects of such PCB accumulation in fish.     

Oil change in excretory products of mussels (Mytilus galloprovincialis)

Oil ingested by mussels appears in the faeces and pseudofaeces but differs in composition from the oil to which the animals are exposed. It contains more heavy fractions and larger aromatics, and there is a shift of aliphatic hydrocarbons towards heavier alkanes and isoprenoids. There is evidence that these changes are the result of metabolic processes in the mussels.     

Characterizing the effect of heavy metal contamination on marine mussels using metabolomics

Marine mussels (Mytilus) are widely used as bioindicators to measure pollution in marine environments. In this study, (1)H NMR spectroscopy and multivariate statistical analyses were used to differentiate mussel groups from a heavy metal-polluted area (Onsan Bay) and a clean area (Dokdo area). Principal component analysis and orthogonal projection to latent structure-discriminant analysis revealed significant separation between extracts of mussels from Onsan Bay and from the Dokdo area. Organic osmolytes (betaine and taurine) and free amino acids (alanine, arginine, glutamine, phenylalanine, and threonine) were more highly accumulated in Onsan Bay mussels compared with Dokdo mussels. These results demonstrate that NMR-based metabolomics can be used as an efficient method for characterizing heavy metal contamination derived from polluted area compared to clean area and to identify metabolites related to environments that are contaminated with heavy metals.     

Uptake and loss of zinc and lead by mussels (Mytilus edulis) and relationships with body weight and reproductive cycle

The uptake and loss of zinc and lead from the whole soft parts of the mussel Mytilus edulis were investigated under natural conditions in north-east England. Mussels in which high concentrations of these metals were found were transferred to an area where low concentrations were found, and vice versa. Mussels from both areas were also kept in tanks and periodic measurements of metal contents were made. Indications of uptake and loss were greatly affected by changing body weights and the work suggests that phase of reproductive cycle (for animals in the environment) and condition (for animals in tanks) have to be closely considered when reporting on levels of metals in mussels, especially in terms of concentration.     

Levels of PCBs and DDTs in mussels from the N.W. Mediterranean

The concentration of synthetic chlorinated hydrocarbons has been monitored in mussels collected on the north-west Mediterranean coast. DDT and PCB contamination is widespread in this region and the results suggest that the mussels are directly exposed to DDT. Seasonal changes in fat content of the mussels and the (unknown) rates of chlorinated hydrocarbon accumulation and excretion make the detailed interpretation of data difficult and limit the value of mussels as bio-indicators of pollution.     

Comparison of the effects of pollution on the marine bivalve Donax trunculus in the vicinity of polluted sites with specimens from a clean reference site (Mediterranean Sea)

The physiological and biochemical characteristics of tissue samples of the marine mussel, Donax trunculus, from an oil-polluted site (Qiryat Yam) and from a site adjacent to an industrial factory (Frutarom) producing polyvinyl chloride (PVC) were compared with samples from a clean reference site (Akko). All sites were located along the sandy shores of the Israeli Mediterranean Sea. The mussels from the oil-polluted site showed increased activity of the system of active transport of organic anions (SATOA) in the gills and the renocardial organ and also of the multixenobiotic resistance transporter (MXR) in the gills. In contrast, samples collected near the PVC factory showed a decrease in SATOA activity and no increase in the activity of MXR in the gills. Specimens from the reference site demonstrated a redox state of equilibrium between energy production and utilization, while in Donax from both the oil polluted and the PVC-polluted sites, the mitochondrial redox state reflected intensive consumption of energy. No significant changes were found in the activity of reduced glutathione s-transferase (GST) in the cytosolic fraction of the digestive gland of Donax collected from any of the three sites. The data demonstrate a differential increase in the anti-chemical defense systems and an intensification of energy metabolism in the mussels exposed to pollution.     

Polycyclic aromatic hydrocarbon pollution in native and caged mussels.

During 1999, a biological monitoring study was conducted at four sites along the Ligurian coast (Cornigliano, Voltri, Vado Ligure and Sanremo). At each site the concentration and composition of polycyclic aromatic hydrocarbons (PAH) were investigated in native and caged mussels. The mussels (Mytilus galloprovincialis), sampled in the Spring and the Autumn, showed different accumulation patterns according to the source of pollution they were exposed to. The PAH concentrations were higher in the native than in the caged mussels. The coastal sites were classified according to PAH concentrations found in mussel tissue samples: Native mussels: Vado Ligure < Voltri < San-remo < = Cornigliano, Caged mussels: Vado Ligure = Voltri = San-remo < Cornigliano. The different classification is explained by the different location of the organisms: native mussels were located near the air-water interface, while caged mussels were situated at -3 m from the water surface. The PAH concentrations in the native and caged mussels showed a similar seasonal variability, and can provide the same information about the sources of PAHs.     

Application of the Mussel Watch concept in studies of the distribution of hydrocarbons in the coastal zone of the Ebro Delta

The Mussel Watch concept was applied in a study of man-induced chemical changes in the Ebro Delta on the Catalonian coast to obtain a preliminary assessment of the distribution of synthetic organic compounds, petroleum and biogenic hydrocarbons in the local coastal zone. Mussels, oysters and clams were selected as the indicator organisms. Levels of petroleum accumulated by mussels were generally high, in the order of 100–800 μg^?1 dry weight, equivalent to those in mussels in the most polluted harbours and bays of California. The relative distributions of the steranes and pentacyclic triterpanes in the mussels were significantly different from those found in petroleum from a local field, indicating that local petroleum was not contributing to the present contamination. The composition of biogenic compounds was variable, probably reflecting differences in the composition of local plankton communities, PCB levels were high in relation to current levels in mussels from US sites, reflecting continuing PCB use in Spain. The Delta appears to be a point source of a number of organochlorine compounds, including HCB, the DDT compounds, endrin and γ-chlordane. Levels of the DDT compound o,p′-DDD, a pharmacologically active substance, were unexpectedly high; identification was confirmed by GS/MS. Many unidentified peaks were present on EC chromatograms, indicating a more complex pattern of contamination than might be suggested by printed summaries of data.     

Asia-Pacific mussel watch: monitoring contamination of persistent organochlorine compounds in coastal waters of Asian countries

Contamination of persistent organochlorines (OCs) such as PCBs (polychlorinated biphenyls), DDT and its metabolites (DDTs), HCH (hexachlorocyclohexane) isomers (HCHs), chlordane compounds (CHLs), and HCB (hexachlorobenzene) were examined in mussels collected from coastal waters of Asian countries such as Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Far East Russia, Singapore, and Vietnam in 1994, 1997, 1998, 1999, and 2001 to elucidate the contamination status, distribution and possible pollution sources and to assess the risks on aquatic organisms and human. OCs were detected in all mussels collected from all the sampling sites investigated. Considerable residue levels of p,p(')-DDT and alpha-HCH were found in mussels and the concentrations of DDTs and HCHs found in mussels from Asian developing countries were higher than those in developed nations suggesting present usage of DDTs and HCHs along the coastal waters of Asian developing countries. On the other hand, lower concentrations of PCBs detected in mussels from Asian developing countries than those in developed countries indicate that PCBs contamination in mussels is strongly related to industrial and activities. To our knowledge, this is a first comprehensive report on monitoring OCs pollution in the Asia-Pacific region.     

Aspects of the usefulness of five marine pollution biomarkers, with emphasis on MN and lipid content

By using cellular biomarkers, such as the formation of the micronucleus, the morphometric alterations of lipids and the morphometric changes in the lysosomal system, we investigated effects of experimental exposure to phenanthrene, Cu, Cd, and Hg for 15 days in mussels. Concerning micronuclei, the evaluation of the total nuclear abnormalities, instead of the micronucleus only, as a biomarker of marine pollution, indicated more statistically significant differences between the control and the pollutant treated groups. Contrary to the existing knowledge showing that there is an increase in lipid content after pollutant exposure, our results showed that there was a decrease in the amount of lipid, as well as an increase in the number of neutral lipids. Furthermore, although prior studies found that fewer lysosomes formed after pollutant exposure, this was not confirmed by our work, as pollutant treated animals exhibited a decrease in the volume and an increase in the numerical density of lysosomes, compared to control groups.     

Trace metals in mussels from the N.W. Mediterranean

A coastal survey in the northwestern Mediterranean region was initiated to measure existing levels of selected trace metals in mussels. For most metals the highest values were found in samples from port cities and areas in the vicinity of river discharge. Marked seasonal variation for many metals was evident; an overall increase in metal concentration in mussels from most stations during March 1974 was attributed to high precipitation and attendant run-off rather than to local pollution. Data comparison indicates that average metal levels in northwestern Mediterranean mussels do not differ markedly from those measured in similar species from different localities throughout the world.     

Heavy metal concentrations and biomarkers of oxidative stress in native mussels (Mytilus edulis chilensis) from Beagle Channel coast (Tierra del Fuego, Argentina)

The aim of this study was to evaluate the usefulness of oxidative stress biomarkers of pollution in native mussels Mytilus edulis chilensis from the Beagle Channel. Spatial and seasonal variations of catalase, glutathione-S-transferase and lipid peroxidation in gills and digestive gland were analyzed in relation to environmental parameters, heavy metals in sediment and in tissue. Four sites with anthropogenic impact and a control site were selected and monitored during the four seasons of 2007. We found significant differences among sites in concentrations of dissolved nutrients and heavy metals in sediments, with the highest values recorded at sites with anthropogenic pressure. Different patterns were observed between concentrations of metals in tissues and in sediments suggesting differences in bioavailability. There were also significant differences in biomarker responses among sites, despite the strong seasonal variability. Our results showed relatively moderate levels of pollution in the study area as a result of urban influences.