The distribution of zinc, cadmium, lead and copper within the hepatopancreas of a woodlouse

The distribution of metals within the hepatopancreas of Oniscus asellus (Crustacea, Isopoda) from two uncontaminated sites, and two sites contaminated with zinc, cadmium and lead, has been studied by atomic absorption spectrophotometry, light microscopy, transmission and scanning electron microscopy and X-ray microanalysis. The hepatopancreas contains two types of intracellular granule. The first type, in the S cells, are spherical granules which contain copper, sulphur and calcium. In woodlice from contaminated sites, these ‘copper’ granules, also contain zinc, cadmium and lead. The second type, in the B cells, are flocculent deposits which contain iron. In woodlice from contaminated sites, these ‘iron’ granules also contain zinc and lead. Moribund woodlice from contaminated sites have large numbers of ‘copper’ and ‘iron’ granules in the hepatopancreas and a fine deposit of zinc and lead on the membranes of the cells. There are numerous microorganisms in close association with the microvillous border of the hepatopancreas of woodlice from all four sites. Within the microorganisms of Oniscus asellus from contaminated sites, there are deposits of material which contain zinc, lead, calcium and phosphorus ‘Copper’ and ‘iron’ granules could have evolved as storage sites for essential metals to be utilized when demand from the body exceeds uptake from the food. Woodlice in contaminated sites may be able to ‘detoxify’ potentially harmful amounts of essential and non-essential metals by storing them in a relatively insoluble form within these granules.     

Effects of mine drainage on the river hayle,cornwall a) factors affecting concentrations of copper,zinc and iron in water,sediments and dominant invertebrate fauna

Concentrations of copper, zinc and iron were measured in waters, sediments and invertebrates collected from the River Hayle. In river water at least 70% of copper and iron was associated with the particulate fraction whereas 80% of zinc was in the soluble form. Although total concentrations of zinc in water exceeded those of copper approximately ten fold, copper predominated over zinc in the sediments by a factor of approximately three. Iron was the most abundant metal recorded in both water and sediments.Seasonal differences in total metal content of waters suggested that concentrations of copper, zinc and iron increased during. periods of high flow and decreased during lower flows. Copper concentrations in the sediment, unlike zinc and iron, showed markedly higher values during the summer sampling period when flows were minimal.In the free-living Trichoptera larvae, concentrations of copper and zinc in the tissue appeared to follow copper and zinc levels in the water. Similar relationships in Odonata and Plecoptera larvae were not obtained. Factors affecting animal/metal relationships are discussed with particular reference to adaptation shown by organisms exposed to high concentrations of heavy metals in their environment.Department of Applied Biology, Cambridge     

Comparison of metal levels in invertebrate detritivores and their natural diets: Concentration factors reassessed

Summary Concentration Factors (ppm in animal: ppm in diet) are presented for lead, zinc and cadmium in the snail Cepaea hortensis, and for lead and zinc in the woodlice Oniscus asellus and Philoscia muscorum, sampled at roadside sites. For each species such factors were found to be extremely variable, affected not only by season, and size and/or age of animals, but also by the choice of data used in estimating metal levels in the diet. It is concluded that factors other than seasonal changes in metal levels of senescent vegetation are primarily responsible for withinsite variation in the lead, zinc and cadmium concentrations of invertebrate detritivores.     

Mercury,cadmium, zinc,copper and selenium in harbour porpoise (Phocoena phocoena) from West Greenland

Muscle, liver, kidney and skin samples taken from 78 harbour porpoises (Phocoena phocoena) were analysed for mercury, cadmium, zinc, copper and selenium. The highest concentrations of mercury were found in the liver (geometric mean 4.17 g/g wet weight), whilst the highest concentrations of cadmium were in the kidney (g.m. 13.2 g/g ww). The levels of cadmium were more than ten times higher than in harbour porpoises from the North Sea and the British NW coast, whilst the mercury levels were about the same. The importance of the cadmium content in the prey is discussed, but this attempt did not revealed the differences. Very high levels of zinc (g.m. 359 g/g ww) and selenium (g.m. 28.6 g/g ww) were found in skin samples, respectively seven and ten times more than in liver. A significant correlation was found between age and the level of mercury and cadmium in all organs. The concentration of mercury and selenium in liver and skin samples and of cadmium and zinc in kidney samples were highly correlated.     

Cadmium, lead, and zinc removal by expression of the thiosulfate reductase gene from Salmonella typhimurium in Escherichia coli

The thiosulfate reductase gene (phsABC) from Salmonella typhimuriumwas expressed in Escherichia coliin order to produce sulfide from inorganic thiosulfate and precipitate metals as metal sulfide complexes. The sulfide-engineered strain removed significant amounts of heavy metals from the medium within 24 h: 99% of zinc up to 500 M, 99% of lead up to 200 M, 99% of 100 M and 91% of 200 M cadmium. In a mixture of 100 M each of cadmium, lead, and zinc, the strain removed 99% of the total metals from solution within 10 h. Cadmium was removed first, lead second, and zinc last. These results have important implications for removal of metals from wastewater contaminated with several metals.     

Heavy metals in Lake George, Uganda, with relation to metal concentrations in tissues of common fish species

The northern end of Lake George, Uganda, and its associated wetlands receive localized metal pollution from a former copper mine and tailings left after metal extraction. The aim of this study was to determine (i) whether the heavy metals are a threat to the biology of the major commercial fish species and (ii) whether consumption of the fish threatens human health. Concentrations of copper, zinc, cobalt and nickel in detrital sediments, plankton, and five fish species from sites in Lake George, the Kazinga Channel and Lake Edward (which are inter-connected) were determined using atomic absorption spectroscopy. The detrital sediments of Hamukungu Bay, Lake George, had average concentrations (g/g dry weight) of 96.3 zinc, 270.4 copper, 57.4 cobalt and 42.8 nickel. There were no significant differences between the Hamukungu Bay and the North Lake George site of Bushatu: both receive inflows from the mining activities. Concentrations of copper and zinc were significantly higher than background values from unpolluted freshwater ecosystems. Plankton samples showed a metal concentration gradient consistent with a gradient from the source of pollution in northern Lake George, along the Kazinga Channel to Lake Edward. The liver tissues of fish had markedly higher concentrations of copper and zinc than flesh. Concentrations of cobalt and nickel were relatively low. The highest mean concentrations of metals in liver tissue occurred in Oreochromis leucostictus (189.0 g/g Cu) and Bagrus docmac (187.5 g/g Zn) whilst the lowest occurred in Oreochromis niloticus (15.3 g/g and 78.2 g/g dry weight copper and zinc, respectively). However, O. niloticus contained the highest concentrations of cobalt (11.2 g/g) and nickel (3.8 g/g). Liver Somatic Indices (LSI) of the fish species from the different sites indicated a reduction of LSI in those fish from the most contaminated zones of northern Lake George compared with all other sites. This suggests there could be anatomical and physiological abnormalities linked to the heavy metal pollution. The flesh had only low concentrations of metals; well within international guidelines for consumption. A person would have to consume 9 kg of fresh flesh of Clarias sp. and 65 kg of O. leucostictus daily to exceed the WHO recommended intake for copper, and even more for other metals. This implies that currently metal pollution in Lake George presents an ecological rather than a human health concern.     

Effects of several metals on spore,biomass, and geosmin production byStreptomyces tendae andPenicillium expansum

Cultures ofStreptomyces tendae andPenicillium expansum grown on Actinomyces and Czapek's media, respectively, were exposed to 5 mg L^–1 of manganese, magnesium, iron, cobalt, nickel, copper and zinc, supplied as sulfate salts. Only copper markedly increased geosmin (1, 10-dimethyl-9-decalol), biomass, and spore production. inductively coupled plasma-atomic emission spectrometric analysis ofS. tendae andP. expansum cells did not indicate an accumulation of copper. Both 1 and 5 mg L^–1 copper, as copper sulfate, increased total geosmin production in cultures ofS. tendae on several media, but decreased production on others, suggesting that substrate composition affects responses to copper.     

Zinc,cadmium, mercury and selenium in minke whales,belugas and narwhals from West Greenland

Summary Samples of muscle, liver and kidney from 24 minke whales (Balaenoptera acutorostrata), 43 belugas (Delphinapterus leucas), and 98 narwhals (Monodon monoceros) were analyzed for zinc, cadmium, mercury, and selenium. Highly significant age accumulation of mercury was found. A lower level of significance of age accumulation of cadmium in belugas and narwhals is probably due to the fact that some of the highest cadmium concentrations are in subadults and young adults. The maximum concentrations of cadmium and mercury are very high: 1.68, 73.7, and 125 g cadmium, and 9.88, 42.8, and 4.61 g mercury per g wet weight of narwhal muscle, liver and kidney, respectively. The cadmium concentrations are correlated in the three organs, as are mercury and to a lesser extent selenium concentrations. The concentrations of mercury and selenium in liver are highly correlated.     

Accumulation of cadmium and copper by the terrestrial snail Arianta arbustorum L.: kinetics and budgets

Summary Specimens of the terrestrial gastropod Arianta arbustorum were fed on cadmium- or copper-enriched agar plates with the aim of performing an input/output analysis and of studying the distribution of these metals in several organs of the snails. After a feeding period of 20 days about 45% of cadmium were lost. 36% accumulated in the hepatopancreas, where a cadmium concentration of more than 500 g/g was measured. The efficiency of cadmium assimilation decreased from about 90% at the beginning to about 55% after 20 days. Copper was distributed more evenly than cadmium, but the main site of copper storage seemed to be the foot/mantle tissues, where 49% of the ingested copper were found. The efficiency of copper assimilation always exceeded 95%. The patterns of distribution and assimilation of copper and cadmium are discussed in relation to differences in the cytological and biochemical detoxification mechanisms which exist for these metals in molluscs.     

Trace metals in edible marine molluscs and crustaceans from Lebanon

Samples of the edible tissue of cephalopod molluscs (cuttlefish, squid, octopus) and crustaceans (lobster, shrimp) collected off the coast of Lebanon were found to concentrate similar levels of cadmium, copper, nickel, and chromium. Lead and zinc were highest in the cephalopods and iron was highest in the crustaceans.The molluscs collected from Beirut had higher levels of many metals than those taken from the other locations. The Beirut octopus had higher lead, cadmium, copper, iron, and chromium. Lead, cadmium, and copper were also highest in the Beirut cuttlefish while iron and zinc were elevated. The crustaceans from Beirut showed no strong tendency to concentrate higher metal levels, except for the Beirut lobster which had higher copper than the other samples.In the cuttlefish, the analysis of bone showed generally higher cadmium, zinc, nickel, and chromium but lower copper and iron than the muscle. However, at Beirut, the bone samples had much higher iron. Levels of most metals in the exoskeletons of the lobster and shrimp were quite similar to those in the muscle tissue with the exception of iron in the lobster which was highest in the exoskeleton, and zinc in both crustaceans, which was more highly concentrated in the muscle.     

Metal resistance in Pseudomonas strains isolated from soil treated with industrial wastewater

Heavy metal concentrations in soil treated with industrial wastewater of Aligarh City (U.P.), India were determined. The analysis of test samples revealed high levels of Fe, Zn, Ni and Cu. A total of 45 Pseudomonas spp. were isolated from soil and were characterized on the basis of morphological, cultural and biochemical characteristics. MICs of Hg²⁺, Cd²⁺, Cu²⁺, Cr³⁺, and Zn²⁺ for each isolate were determined. Eighty percent of the strains isolated from soil harboured resistance to copper, whereas 73.3% of the isolates exhibited resistance to cadmium, 71.1% to chromium and zinc and 48.8% to mercury. A maximum MIC of 200 g/ml for mercury and 1600 g/ml for other metals was observed. Metal resistance was found to be plasmid mediated as evidenced by transformation studies. Further, the transmissible nature of chromium resistance was confirmed by conjugation. Agarose gel electrophoresis using the miniprep method for plasmid isolation revealed that these isolates harboured plasmids of molecular weights (45 & 47 kb) using EcoRI and HindIII digests of DNA and undigested DNA as standard markers.     

The anthropogenically stressed periphyton of Lake Orta,Italy

A long history of discharge of industrial wastes has left Lake Orta contaminated with high concentrations of acid, ammonia and copper. To study the effect of this chronic pollution on periphyton, I sampled epilithic algae and associated invertebrates at several sites from 1987 to 1988. Although biomass varied both spatially and seasonally, the taxonomic composition of these communities remained relatively stable. The dominant algae were chlorophytes and the dominant invertebrates were trichopterans. Comparisons with nearby unpolluted Lake Mergozzo, and with general equations developed for neutral lakes in North America indicate that these anthropogenic stresses are more clearly reflected by changes in the taxonomic composition and size distribution of the community than by changes in its biomass.Contribution No 375 from the Groupe de recherches en Ecologie des Eaux douces, Université de Montréal.Contribution No 375 from the Groupe de recherches en Ecologie des Eaux douces, Université de Montréal.     

Selection favours low hsp70 levels in chronically metal‐stressed soil arthropods

Thirty‐eight populations of woodlice (Oniscus asellus, Porcellio scaber) and millipedes (Julus scandinavius) from 28 differently metal‐polluted field sites were analysed for their 70‐kDa stress protein (hsp70) level. Although ANOVA revealed significant dependence of the hsp70 level on the concentrations of water‐soluble lead, cadmium and zinc and the soil pH, each of these parameters accounted for at most 18% of the intersite variability of the stress protein level only. A multivariate model based on multiple regression analysis explained more than 96% of hsp70 variance and revealed both the pollution history of a site (strong metal contamination for more than 70 years) and invertebrate species identity to act as the most important parameters. The model accounted for the observation that most of the populations from long‐term polluted sites exhibited comparatively low stress protein levels in response to their own (contaminated) habitats. In contrast, isopods (O. asellus) from a control site were not able to maintain a low hsp70 level when they were exposed to either an artificial metal cocktail or soil taken from one of the contaminated field sites. They did not acclimatize to the exposure conditions within 3 months. We propose that selection of insensitive phenotypes in long‐term polluted soils has taken place so as to minimize the stress protein level which, in turn, is indicative of high intracellular protein integrity. Long‐term selection for a high hsp70 level to compensate for adverse metal impact was not observed, which suggests that such a strategy may trade off against other fitness consequences. In this context, insensitivity to metal stress involved increased selectivity in food choice and reduced variability in stress response. Multiple regression models showed species‐specificity in those abiotic factors which determined (1) high hsp70 levels in sensitive populations as well as (2) low hsp70 levels in insensitive ones. Therefore, abiotic factors can be assigned to act as the main components of selection: lead and cadmium for J. scandinavius and O. asellus, zinc for P. scaber.     

Benthic algal populations respond to aluminum,acid, and aluminum-acid mixtures in artificial streams

Elevated aluminum (Al) concentrations are often associated with acid-stressed aquatic ecosystems, so it has been unclear whether acidic water or elevated Al is more responsible in changing community composition. Experiments were done to investigate effects of acidification and increased Al on the abundance of benthic algae in artificial streams supplied with natural water and nominal treatments of (a) pH 4.8, (b) 500 µg l^-1 Al, or (c) the mixture of pH 4.8 and 500 µg l^-1 Al compared to a control without added Al or acid. These treatments are referred to as Acid, Al-only, Acid + Al, and the control, respectively. In the Acid treatment the abundance of two diatoms, two green algae, dry weight biomass, and chlorophyll a decreased; one diatom and one filamentous blue-green alga increased. In the Al-only treatment, densities of two diatoms, one green alga, one blue-green alga, dry weight biomass, and chlorophyll a increased. In the Acid + Al treatment, abundances of one green alga, two blue-green algae, and concentrations of chlorophyll a decreased below the levels observed in the Acid treatment. Acid and Al concentrations were altered by each other and by chemical and biological processes in the stream system. Species of diatoms, green algae, and blue-green algae responded individually to treatments and mixtures of acid and Al. Shifts in the abundance of species may change food web relationships for higher-level consumers, and algae may be useful biomonitors of ecological stress.     

Effects of long-term in vitro exposure to aluminum,cadmium or lead on differentiation and cholinergic receptor expression in a human neuroblastoma cell line

Neurotoxicity of long-term exposure to lead, aluminum and cadmium has been studied in vitro on the human neuroblastoma cell line IMR32 by measuring cytotoxicity, and the effects on neuronal-specific characteristics such as nitrite outgrowth and expression of cholinergic receptors as parameters of toxicity. Cytotoxicity was highest with cadmium, intermediate with lead and lowest with aluminum exposure. Lead, but not cadmium and aluminum, interfered with neurite growth. The expression of a-bungarotoxin binding sites and muscarinic receptors was markedly increased by cadmium and not affected by aluminum exposure. Lead induced only an increase of toxin binding sites. These in vitro modifications are discussed in relation to the possible use of neuronal cell lines for detecting neurotoxic effects of heavy metals.Abbreviations ACh acetylcholine - -Bgtx -bungarotoxin - BrdUr 5'-bromodeoxyuridine - CNS central nervous system     

Enteromorpha as a monitor of heavy metals in estuaries

An account is given of the use of Enteromorpha to monitor zinc, cadmium, mercury and lead pollution in six estuaries and the British North Sea coast. The ranges for each element were: Zn, 19–437 µg g^–1; µg g^–1 Cd, 0.07–4.8 µg g^–1; Hg, 0.02–0.23 µg g^–1. It is suggested that tissue analysis of Enteromorpha is one of the most useful biological techniques available in estuaries for pin-pointing aqueous (as opposed to sediment) metal contamination, and also for providing data suitable for world-wide comparisons. Provisional values are given for concentrations corresponding to moderate and high pollution.Deceased     

Heavy metals in the terrestrial isopod Porcellio scaber Latreille. II. Subcellular fractionation of metal-accumulating lysosomes from hepatopancreas

Two populations of metal contaminated Porcellio scaber Latreille were studied: one consisting of animals that had been fed heavy metals in the laboratory for several months, and one from a metal-polluted site in the field (Braubach, FRG). Density gradient centrifugation was performed on hepatopancreas homogenates in order to identify cellular fractions and their association with lead, copper and cadmium. Marker enzymes were used for localisation of cellular fractions in the density gradient. Two lysosomal fractions, called the light and heavy fraction, were separated. They contained mainly lead, but also copper and some cadmium.Abbreviations AP acid phosphatase - ER endoplasmic reticulum - LDH lactic dehydrogenase - MDH malic dehydrogenase - NADH nicotinamide adenine dinucleotide - P. scaber Porcellio scaber     

Atomabsorptionsmessungen von Blei,Cadmium, Kupfer,Eisen und Zink im Seston der Ostsee

Zusammenfassung 1. Auf einer Forschungsfahrt in die Ostsee im April/Mai 1973 wurden 100 Sestonproben entnommen und auf ihren Gehalt an Blei, Cadmium, Zink, Kupfer und Eisen mit Hilfe der flammenlosen Atom-Absorptions-Spektrometrie analysiert.2. Die mittlere Konzentration im Seston der Ostsee beträgt für Blei 123 ppm, für Cadmium 5,8 ppm, für Zink 300 ppm, für Kupfer 61 ppm und für Eisen 3535 ppm.3. Im Vergleich zu Metallanalysen ozeanischen Sestons müssen die Blei- und Cadmiumkonzentrationen als stark überhöht angesehen werden.4. Die Konzentrationen des partikulär gebundenen Eisens, Zinks und Kupfers können bis auf lokal stark erhöhte Eisen- und Zinkkonzentrationen als natürlich angesehen werden.5. Arbeitsweise und Meßgenauigkeit der Metallanalytik werden beschrieben.

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Atomic absorption measurements of lead, cadmium, copper, iron and zinc in seston of the Baltic Sea

During a cruise with R. V. Alkor from Kiel Bight to Finnish Bay, nearly 100 seston samples were taken during April/May 1973. Samples from the 23 stations were analyzed for lead, cadmium, copper, iron and zinc by flameless atomic absorption spectrometry. The mean values for lead and cadmium were 123 and 5.8 ppm, respectively; for zinc, 733 ppm, for copper, 61 ppm, and for iron, 3535 ppm. In contrast to trace-metal analyses of off shore seston, the concentrations for lead and cadmium in Baltic-Sea seston are very high; these results are in good agreement with analyses of the dissolved metals. The concentrations of zinc, copper and iron in the particulate matter from the Baltic-Sea, apart from some local influences, agree well with values published from the concentrations in off shore seston. The distribution and variation of the individual values are discussed. The method for analysing the metals and its precision are briefly described.

     

Perturbation of monovalent cation composition in Ulva lactuca by cadmium, copper and zinc

Discs of thallus cut from the macroalga Ulva lactuca were incubated in filtered seawater containing cadmium, zinc, copper or cobalt (30 m). The metal uptake rates differed for each metal in the order Cu > Zn > Cd > Co. Exposure of the macroalga to metals resulted in a disruption of intracellular monovalent cation composition. Intracellular potassium was irreversibly lost and sodium was accumulated by cadmium- or copper-treated U. lactuca, which was assumed to indicate irreversible disruption of the plasmalemma. Exposure to zinc caused an increase in sodium concentrations, whereas potassium concentrations were not significantly different from the controls, suggesting that the integrity of the plasmalemma had been maintained at the zinc concentration used. Intracellular magnesium was also lost from copper-treated algae, which again indicated a loss of integrity of the cell membrane.     

Conquering terra firma: The copper problem from the isopod's point of view

Summary 1. Copper is an element of great importance for crustaceans such as isopods and amphipods. While their marine relatives can obtain all necessary chemical components from the surrounding sea water via gills or other epithelia, the species which have conquered terra firma face the problem of extracting practically all vital substances from their food.2. In marine forms, the water flow maintained via ciliary or muscular mechanisms is sufficient to provide several orders of magnitude more copper than required; food probably plays only a minor role in copper supply.3. Terrestrial isopods have to rely entirely on their food as a source of copper. They can do several things in order to ensure an adequate supply: increase food consumption, improve the selective absorption of copper from the food material passing through the gut (possibly in symbiosis with copper concentrating micro-organisms), increase copper stores, thus widening safety margins for times of low supply, reduce copper losses by regulating the transport of this metal between the stores and other body parts.4. It was shown that terrestrial isopods consume about as much food as their marine relatives.5. Extraction of copper from primary vegetable matter seems to be very difficult, both for terrestrial forms likePorcellio scaber and for intertidal forms such asLigia oceanica or the amphipodOrchestia gammarella; extraction is possible only at very high copper concentrations.6. A way out of this calamitous situation seems to be in cooperation with micro-organisms which liberate copper from the tightly bound states in which it exists in the primary plant material. This is true forP. scaber but it probably also holds forO. gammerella, L. oceanica and other species feeding on decaying algae on the shore.7. The amount of copper stored in the hepatopancreas increases with increasing dependence of the species on the terrestrial environment, the values obtained for intertidal species being intermediate between marine and truly terrestrial species.8.P. scaber (and probablyOniscus asellus) will extract up to 95% of the copper present in artificially enriched leaf litter whereas intertidal forms feeding onFucus will not extract more than 50%, mostly only 20% or less, from artificially enriched seaweeds.9. Copper is more strictly relegated to storage cells of the hepatopancreas in terrestrial isopods than it is in marine or intertidal ones. Extensive movements of copper inP. scaber are accompanied by the synthesis of special carrier proteins, whereas in marine or intertidal species this metal seems to be able to move more freely in an easily dissociable state between the storage cells and other cells of the hepatopancreas.

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Eroberung des Festlands: Das Kupferproblem vom Gesichtspunkt der Isopoden

Kurzfassung Marine Crustaceen müßten theoretisch in der Lage sein, dem Atemwasser genügend viel Kupfer zu entnehmen, um selbst schwerste tägliche Verluste zu ersetzen. Im Vergleich dazu dürfte das in der Pflanzennahrung angebotene Cu mengenmäßig eine nur geringe Rolle spielen. Dennoch muß das vegetabilische Cu ausreichen, um den Bedarf herbivorer terrestrischer Crustaceen an diesem Metall zu decken. Die Probleme, die im Zusammenhang mit der Immigration vom Meer zum Land hinsichtlich der Kupferversorgung entstehen, werden am Beispiel litoraler und terrestrischer Isopoden und Amphipoden — zum Teil in spekulativer Form — diskutiert. Vergleichende Untersuchungen haben ergeben, daß terrestrische und litorale Isopoden die Menge der aufgenommenen Nahrung gegenüber marinen Arten nicht erhöhen und daß die Assimilation von Cu aus der Nahrung in ausreichender Weise nur durch die Beihilfe von Mikroorganismen möglich zu sein scheint. Der Zugang zu einem nährstoffreichen, von Mikroorganismen gut durchgearbeitetem Substrat muß also eine der Hauptvoraussetzungen für eine funktionierende Kupferversorgung aus pflanzlichem Material sein. Außerdem nimmt die Menge des im Hepatopancreas gespeicherten Cu in der Reihe marine — litorale — terrestrische Crustaceen zu. Auch die Leistungsfähigkeit der Kupferassimilation ist im Vergleich zu litoralen bei terrestrischen Isopoden größer. Während beiPorcellio scaber die Kupferassimilation in direkter Abhängigkeit vom Kupfergehalt der Nahrung steht und Werte über 90% erreichen kann, beträgt beiLigia oceanica undOrchestia gammarella die Kupferassimilation bei mittlerem Kupfergehalt (0,2 bis 0,3µg/mg Trockengewicht) nur etwa 66%, um dann wieder abzunehmen. Schließlich wird im Vergleich zu marinen und litoralen Isopoden der Kupferstoffwechsel terrestrischer Isopoden besser geregelt, indem Cu ausschließlicher in besonderen Zellen gespeichert und jede umfangreiche Mobilisierung des Metalls von der Synthese charakteristischer Sekrete begleitet wird, die Stoffe (wahrscheinlich Proteide) enthalten, deren Aufgabe zu sein scheint, freies Cu zu binden. Dies würde sowohl dessen toxische Eigenschaften reduzieren, als auch Verluste dieses Metalls an das Blut und in das Darmlumen verhindern.