Genetic diversity and metal tolerance of two marine species: a comparison between populations from contaminated and reference sites

Long-term contamination of the marine environment surrounding a lead smelter offered a unique opportunity to examine how pollutants might have acted to alter genetic characteristics of populations of organisms in the receiving system. This study used random amplified polymorphic DNA analysis to compare the genetic diversity of populations of the prawn, Leander intermedius, and the isopod, Platynympha longicaudata from the smelter discharge site with reference populations. The genetic diversity of the prawn population from the smelter discharge site (Port Pirie) was lower than that found in one reference population, and not significantly different from the other two reference populations. Genetic diversity of the Port Pirie population of isopods was found to be significantly lower than that of all reference populations. Prawns and isopods were also exposed to metal mixtures in the laboratory in a similar ratio to that found in seston near the smelter effluent discharge site. Both pre-exposed and reference populations of prawns tolerated elevated levels of metals and exhibited no significant difference in response. This contrasted with the isopods, with the pre-exposed isopod population showing greater tolerance to elevated metal levels compared with the reference population. These results highlight the need to include a number of reference populations for comparative purposes in genetic diversity studies, and the need to assess the influence of pollution on the genetic diversity of more than one species if genetic diversity analyses are to be used to gauge remediation success.     

Trace metals in finfish from the New York Bight and Long Island Sound

Concentrations of silver, cadmium, chromium, copper, mercury, manganese, nickel, lead and zinc were measured in five species of finfish collected from the New York Bight and two from Long Island Sound. With few exceptions the trace metal contents were similar for the various species examined and also for a single species when comparing catch locations. Metal levels also were similar to concentrations reported by two other investigators who studied fish from the North Atlantic.     

Distribution of heavy metals in Port Phillip Bay

The distribution of cadmium, copper, iron, manganese, lead, and zinc in sediments of Port Phillip Bay, Victoria, Australia was investigated, and the impact of industrial discharges studied. The pre-cultural levels for these metals are in nearly all cases far less than the post-cultural levels, especially in those sediments deposited in the last half century in the vicinity of urbanized areas.     

Lead in Port Phillip Bay mussels

Lead levels in the indicator mussel Mytilus edulis, exceeds the WHO food standards in 19 of the 22 locations sampled in Port Phillip Bay, Melbourne. While this seriously reflects contamination of the food chain, LD₅₀ experiments on Mytilus indicate that the lethal effect of lead on this organism is much less severe than excessive doses of mercury, cadmium, copper or zinc. Little is known about the long term effects of lead on Mytilus.     

Comparative concentrations of metals in marine species from French Frigate Shoals, North Pacific Ocean.

Concentrations of arsenic, cadmium, chromium, copper, lead, mercury, selenium, and zinc were measured in coral, crab, eel, fish, lobster, and sediment samples collected from French Frigate Shoals, North Pacific Ocean. The sediments contained relatively high concentrations of selenium; moderate concentrations of arsenic, cadmium, copper and lead; and low concentrations of chromium and zinc. Metal concentrations were also determined in coral and crabs collected from the island of Oahu. Notably, a crab (Grapsus tenuicrustatus) and the undulated moray eel (Gymnothorax undulatus) exhibited high levels of copper and arsenic, respectively, relative to the other species studied. The concentrations of arsenic in the eel averaged 225 microg g(-1) dry wt, which was 3-12 times higher than that in all of the other species tested. The average concentration of copper in the crab was 343 microg g(-1) dry wt, 3-86 times greater than that in the other species studied. These data indicate background and comparative levels of the metals among the studied species. Lead levels in the coral (9-10 microg g(-1) dry wt) and crab (42-57 microg g(-1) dry wt) from Tern and Disappearing Islands were 23-283-fold greater than those from Oahu (0.4 and 0.2 microg g(-1) dry wt, respectively).     

Measurement of environmental trace-metal levels with transplanted mussels and diffusive gradients in thin films (DGT): a comparison of techniques

Transplanted mussels and diffusive gradients in thin films (DGT) were used to assess levels of cadmium, copper, lead and zinc at four sites situated inside and outside of two enclosed marinas, near Melbourne, Australia. Mussels accumulated all metals except cadmium. Over one year, there were large temporal differences in tissue metal levels in mussels, but differences between sites were only apparent for copper and lead. DGT showed temporal differences of the same kind as those seen in the mussels, but appeared to have more power to discriminate between sites. DGT found higher copper levels inside marinas than outside, and high levels of zinc were found inside one marina. Levels of copper and zinc were high enough to be of environmental concern for one site. The effect of fouling on DGT measurements will have to be quantified, or avoided by the use of multiple short-term exposures, if the technique is to become a widespread in situ monitoring tool.     

Trace metals in fish and invertebrates of three California coastal Wetlands

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in microgram/g) found in biota were: Zn 12-650; Cu 1.9-440; Ni < 1-37; Cr < 1-55; Pb < 0.5-6.8; As < 1-8.5; Se < 1-3.8; Cd < 0.2-0.90; and Ag < 0.3-5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 micrograms/g) and the two water-column fish sampled (Fundulus parvipinnis and Atherinops affinis) (30 and 24 micrograms/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 micrograms/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6-55 and 2.6-37 micrograms/g), the most northern site and an active military base, and Ballona (< 1-30 and < 1-16 micrograms/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.     

Seston and sediment in Lake Norrviken

Seston and sedimenting material were measured over several years in a lake in central Sweden. The origin of the material is discussed on basis of the chemical composition and the amounts in terms of successively changing environmental conditions (mainly phosphorus). Assimilation of N and P by phytoplankton is calculated from the elemental composition of net plankton combined with C-14 data of C assimilation. Changes in the amount of seston are small compared to production, mineralization and sedimentation.     

Selenium and heavy metals in black marlin

Black marlin from the apparently unpolluted waters off north-eastern Australia have the highest muscle and liver concentrations of total mercury yet reported for a teleost species. Selenium concentrations are also high. There is a significant correlation between mercury and selenium concentrations, and concentrations of both those elements are significantly correlated to size of fish. Concentrations of cadmium, lead, zinc, copper or arsenic are not so correlated.The results of this study indicate there is a need for a moratorium on the use of this species for human consumption.     

Water quality control and its effect on the concentration of heavy metals in Port Kembla Harbour,N.S.W.

The concentrations of five heavy metals (iron, lead, zinc, copper and cadmium) were measured at two sites in Port Kembla Harbour over a period of 9 months. In comparing the results of this study with those recorded previously at these sites during 1974 and 1978, it is shown that the concentrations of all five metals have decreased substantially over the last decade. It is proposed that this decrease is due to the implementation of water quality control programmes by industries in close proximity to the harbour. The problems associated with undertaking future programmes in systems such as Port Kembla Harbour are discussed in the light of these results.     

Trace elements in farmed and wild gilthead seabream, Sparus aurata

In the present study, we sought to determine the concentration of several trace elements (total and organic mercury, selenium, cadmium, lead, arsenic, copper, chromium, iron, manganese, molybdenum, vanadium and zinc) in muscle tissue of gilthead seabream (Sparus aurata), an edible finfish species that is widely cultured in the Mediterranean area. The phenomenon of bioaccumulation and bioamplification (especially of mercury) was investigated by comparing farmed fish with wild specimens of the same species. Farmed specimens showed mercury and arsenic concentrations significantly lower than wild specimens, and no relationship was found between mercury concentration and body size. The lower level of methylmercury in farmed fish has important implications for consumer health.     

Organochlorine compound and trace metal contaminants in fish near Sydney's ocean outfalls

Sydney's inshore sewage outfalls were significant contributors to organochlorine contamination of inshore sedentary fish such as red morwong. Diversion of the sewage to deepwater outfalls has resulted in marked declines in the concentrations of these compounds in inshore red morwong. Apart from lead, however, similar trends did not occur for concentrations of trace metals. A wide variety of trace metals and organochlorine compounds were found in the flesh and/or livers of a variety of fish species caught at sites associated with the present deepwater ocean outfalls off Sydney. Fish caught at locations remote from Sydney also contained a wide variety of trace metals although organochlorine compounds were usually at lower levels. The mean contaminant levels in all species of offshore fish were generally found to be low when compared to the Australian National Food Authority's Maximum Residue Limit (NFA MRL). No fish analysed was found to have levels of an organochlorine compound above the MRL and no fish was found to have levels of zinc or lead above the MRL. When detected, fish with levels of a trace metal above the MRL appeared to be distributed throughout New South Wales, independent of the deepwater ocean outfalls off Sydney. There is no evidence as yet that the commissioning of the deepwater outfalls has led to an increase in levels of contaminants in the fish examined to the extent that they are of concern relative to the NFA MRLs.     

Statistical analysis of trend monitoring data of heavy metals in flounder (Platichthys flesus)

Six years trend monitoring data of mercury, cadmium, copper, lead, and zinc in flounder from the Sound and the Great Belt (Danish coastal waters) are statistically assessed using a series of multilinear, regressive models in terms of the measurements of metal levels and various biological parameters (e.g. length) for individual fish. With the exception of zinc in females from the Great Belt, each element exhibited no significant differences in relation to biological parameters from year to year at the two areas. Linearly increasing trends in the concentrations were found for cadmium without sex dependance from the two areas and for zinc and copper in females from the Sound and zinc in males from the Great Belt. Zinc is, in both areas, significantly correlated with the sex as is copper in the flounder from the Sound. The statistical models used have been found very useful and easy to interpret.     

Trace metal solubility in an anoxic fjord

Intermittent anoxia in the Saanich Inlet water column provides an easily accessible marine O₂/H₂S interface to study the response of metals to both a steep redox gradient and the availability of reactive reduced sulfur species. Our study indicates a strong anoxic zone sink for copper and cadmium and the characteristically enhanced solubility of manganese and iron. Thiosulfate and sulfite are below detection limits (1 μM and 0.1 μM, respectively) and thus not important in metal complexation. Elemental sulfur concentrations are high at the oxic/anoxic interface and throughout the anoxic zone, indicating the potential for metal complexation by polysulfides. A thermodynamic approach employing metal sulfide formation and class specific sulfidic ligand complexation to generate equilibrium profiles adequately describes the solubility of iron, copper, and cadmium. The extension of this scheme to other transition and class B metals in other marine environments with redox fronts is suggested.     

Impaired Functions in Nile Tilapia,Oreochromis niloticus (Linnaeus, 1757), from Polluted Waters

Oreochromis niloticus is an endemic species in the River Nile and represents the main object of fishery in the Nile Delta Lakes of which Lake Maryût is the smallest and most polluted. Due to current pollution problems, fish production in the lake greatly declined. Besides fish biology, this study considered a wide array of water databases in selected sites along the lake. Hydrologic and biologic data were compared to that of a reference fish hatchery. Water concentrations of ammonia, manganese, nickel, cadmium, lead and mercury proved hazardous to fish, whereas chromium, copper, iron, zinc, pH, alkalinity, hardness, phosphate, nitrate, and nitrite always fell within acceptable levels. Physiologic evaluation of O. niloticus pointed out improper growth, protein inadequacy, and functional impairment in fish inhabiting polluted sites, in particular the lake main basin. These were reflected by data of specific formulae as RNA/DNA and the relative RNA content (r) in cells of the liver and gill arches as well as by the relative mobilization of serum protein fractions. It seems, however, that growth competence is additionally affected by the stress impact exerted upon fish by massive population numbers in some cramped commercial ponds.     

Heavy metal residues in tissues of marine turtles

Heavy metal concentrations in the tissues of marine turtles are presented. The most frequently monitored elements are mercury, cadmium and lead; and the tissues mainly analysed in nearly all the stranded individuals are muscle, liver and kidney. The highest mercury and cadmium levels were found in liver and kidney respectively; the majority of the lead burden existed in bones and carapace, while arsenic was present mainly in muscle tissue. Mercury occurred quite completely as methylmercury in muscle, whereas in liver the main form was the inorganic one. Arsenic was exclusively present in the metallorganic form either in muscle tissue or in liver. Metals in the eggs were mainly present in the yolk. Significantly higher concentration of mercury, copper, zinc and iron were found in yolk than albumen, while shell contained highest levels of manganese and copper. The load of trace metals in these animals strictly correlated with the species seems to depend on their different food behaviour.     

Evaluation of the Relative Resistance of Twelve Species of Fish in Toxicity Bioassays with Electroplating Waste

The present paper deals with the evaluation of the relative resistance of 12 species of fish in static toxicity bioassay tests of electroplating waste. The electroplating waste is highly toxic as it contains several toxic metals like copper, nickel, cadmium, zinc, lead and chromium alongwith cyanides, acids and alkalies. On the basis of TL₅₀, the fish Clarias batrachus ist the most resistant fish and Labeo rohita the most sensitive. The relative resistance of the fish is in the decreasing order: Clarias batrachus, Saccobranchus fossilis, Ophiocephalus gachua, Ophiocephalus punctatus, Puntius stigma, Puntius sophore, Mystus vittatus, Cyprinus carpio, Colisa fasciatus, Notopterus notopterus, Cirrhina mrigala and Labeo rohita.     

Seston fatty acid composition and copepod RNA:DNA ratio with respect to the underwater light climate in fluvial Lac Saint-Pierre

The relationship between the underwater light availability at different wavelengths (from 351 to 700?nm) and the fatty acid (FA) composition of seston, as well as the trophic transfer of fatty acids from producers to consumers and its influence on copepod growth condition, were investigated throughout fluvial Lac Saint-Pierre (Québec, Canada). Seston and zooplankton were collected at 11 sampling sites located within distinct water masses discriminated according to their underwater spectral characteristics. Diffuse light attenuation coefficients (K_d(??)) varied among sampling sites and wavelengths (??) and were negatively correlated to seston composition in some essential fatty acids. Particularly, the relationships between K_d(??) and the seston concentration in 20:5n3 and 22:6n3 differed and were wavelength dependent, being stronger for ?? close to the absorption maxima of chlorophyll a, suggesting a potential link with photosynthetic processes. The concentrations of 16:1n7, 18:3n3 and 20:5n3 in copepods were strongly correlated to those in the seston, which points towards the trophic transfer of these fatty acids between primary producers and herbivorous consumers. Moreover, the growth condition of copepods, as expressed by their RNA:DNA ratio, was correlated to the concentrations of 16:1n7, 18:3n3 and 20:5n3 in the seston and in copepods. Our field study sheds light on the potential importance, yet to be precised, of specific wavelengths as a driver of Lac Saint-Pierre??s productivity through their influence on fatty acids composition of seston and its nutritional quality for primary consumers.     

Heavy metals in surface sediment and epibenthic macroinvertebrates from the coastal zone and continental slope of Kenya

In surface sediments, a statistically significant increase was measured in the concentration of copper and cadmium along all transects, and of zinc along only the most southern (Gazi) transect, radiating into the Indian Ocean perpendicular to the Kenyan coast. Mean copper and cadmium increased from 5 to 30 μg g⁻¹ dry wt and from 0.01 to 0.34 μg g⁻¹ dry wt in shallow coastal (±20 m depth) to deep-sea stations (±2000 m depth), respectively. These gradients were found both during the south-east monsoon and north-east monsoon period. The shallow estuarine zone of the Sabaki river mouth showed significantly enhanced levels of total organic carbon and nitrogen and all metals analysed, except cadmium.In crustaceans, the concentration of copper and particularly cadmium was significantly above baseline levels, varying from 45 to 90 μg g⁻¹ dry wt and 1.0 to 8.5 μg g⁻¹ dry wt, respectively. Zinc levels (49–102 μg g⁻¹ dry wt) were at about baseline levels or a little elevated. On the contrary, lead showed very low concentrations, varying from 0.1 to 0.6 μg g⁻¹ dry wt. Other species generally showed the same pattern.