Larval development of hermit crab Clibanarius longitarsus: Synergistic effect of heavy metals

The levels of heavy metals copper and zinc were found to be high in the Vellar estuary. Therefore their effects on the larval development of the abundant hermit crab Clibanarius longitarsus were studied individually and in combination from hatching till moulting to glaucothoe stage in the laboratory using freshly hatched Artemia nauplii as food. The 96 h LC50 values found with 100 larvae each kept in 10 different concentrations of copper and zinc (350, 300, 250, 200, 150, 100, 50, 25, 10 and 5 ppb) were 50 ppb for copper and 90 ppb for zinc. Based on these 96 h LC50 values, three sublethal concentrations were chosen for the metals copper and zinc at 50%, 25% and 10% levels of the LC50 values. With increase in concentration of the test medium, the survival rate decreased and the time required for the completion of each zoeal stage increased. Copper was found to be more toxic than zinc as the survival rate in copper concentrations was lower than those in zinc concentrations. The survival rate in the mixed concentrations of metals was lower than in individual concentrations.     

Hepatic metallothionein production and resistance to heavy metals by rainbow trout (Salmo gairdneri)--I. Exposed to an artificial mixture of zinc, copper and cadmium

Rainbow trout developed elevated hepatic metallothionein concentrations after 4 weeks in a solution containing zinc, copper and cadmium in a fixed ratio of 400:20:1. Resistance to a combination of these metals increased in proportion to the concentration to which they were exposed for 4 weeks. The concentration of copper but not zinc or cadmium in the low molecular weight proteins separated by gel filtration was related to the concentrations of metallothionein present. The combined toxicity of the metals in the mixture was additive.     

Seasonal variation in trace metal concentrations in three talitrid amphipods from the Gulf of Gdansk, Poland

Talitrid amphipod crustaceans are increasingly being used as biomonitors of trace metal bioavailabilities in coastal waters, and it is important to understand how other factors, in addition to metal pollution, might affect their accumulated body concentrations. Seasonal variation (April-October 2000) in body concentrations of copper, zinc, cadmium, iron, manganese, lead and nickel has been investigated in three species, Orchestia cavimana, Talitrus saltator and Talorchestia deshayesii, from the region of the Gulf of Gdansk (including the Vistula Lagoon), Poland, an area with considerable temperature variation between summer and winter. Seasonal variation in the body metal concentrations of talitrid amphipod crustaceans was confirmed in each population, but only copper showed a consistent pattern. Copper concentrations fell from early to late summer, perhaps either as a result of the replacement of the older overwintering generation by the younger spring one, or as a result of the loss of haemocyanin in autumn amphipods entering a period of low metabolic activity. Metal concentration data for T. saltator from Gdynia-Osada Rybacka compared with equivalent data for 1996 and 1998 show a significant drop in metals associated with the influx of the Vistula river water, which occurred in 1998, following a major flood event in 1997.     

Haemolymph protein composition and copper levels in decapod crustaceans

Variations in haemolymph protein composition and concentration, in copper content and copper distribution in the tissue of decapod crustaceans are reviewed. Haemocyanin is the major haemolymph constituent (> 60%); the remaining proteins (in order of concentration) include coagulogen, apohaemocyanin, hormones and antisomes. Moulting, nutritional state, infection, hypoxia and salinity fluctuations are the major factors affecting the relative proportions and total quantities of the haemolymph proteins. With regard to haemocyanin, the changes in concentration during the moult cycle are principally associated with changes in haemolymph volume, rather than with changes in total haemocyanin content due to synthesis or catabolism. The role of the midgut gland in regulating haemolymph copper and haemocyanin concentration has been re-evaluated. More than 50% of the whole body copper load is stored in the haemolymph. In contrast, less than 3% of the copper load resides in the midgut gland. The latter has little potential for regulating haemolymph copper levels, at least in the short term (hours to a few days), though it may be involved in regulating haemocyanin levels over longer periods (weeks to months). The total copper content of the haemolymph remains within a narrow range, except during starvation when levels may decrease. Consequently, variations in the copper content of soft tissues, which constitute only 20% of decapod dry weight, do not significanlty alter whole body copper concentrations. Evidence that copper released following haemocyanin catabolism becomes bound to metallothionein for later use in the resynthesis of haemocyanin is reviewed and found to be inconclusive. The amount of copper that can be stored in this way is trivial compared with the amount of copper required to permit significant changes in haemolymph haemocyanin concentration. Average tissue copper requirements, calculated during the present study, are approx. 4 times higher than previous theoretical estimates.     

Effects of copper aspirinate and aspirin on tissue copper,zinc, and iron concentrations following chronic oral treatment in the adjuvant arthritic rat

Concentrations of copper, zinc, and iron were analyzed and compared in a number of tissues of adjuvant arthritic rats following 22 d of chronic treatment (per os) with either vehicle, aspirin or copper aspirinate, at doses of 100 mg/kg, 200 mg/kg, or 400 mg/kg. Such chronic treatment resulted in a negative balance in copper, zinc, and iron in many tissues. Among the tissues examined, liver and kidney exhibited the greatest changes in metal concentrations; brain and skeletal muscle exhibited the least. Arthritis-induced changes in the concentrations of all three metals in the liver were reversed upon treatment with aspirin. Treatment with copper aspirinate, on the other hand, resulted in an extremely high accumulation of copper in the liver. Arthritis-induced changes in copper, zinc, and iron concentrations in the pancreas and copper concentration in the plasma were generally not reversed upon treatment with either aspirin or copper aspirinate. Among the three metals examined, the degree of change observed as a result of drug treatments was greatest for iron and least for zinc. Finally, it appeared that the effects of aspirin and copper aspirinate on tissue metal concentrations were independent of the antiarthritic effects of these compounds.     

The effect of copper and zinc at neutral and acidic pH on the general haematology and osmoregulation of Oreochromis mossambicus

The objective of this study was to determine the effect of sublethal copper and zinc concentrations at a neutral and an acidic pH, on selected haematological parameters as well as on the total osmolality and electrolyte concentrations of Oreochromis mossambicus. In general, at neutral pH copper and zinc caused blood acidosis, increases in circulating white blood cell numbers, causing stimulation of the immune system, and a rapid release of red blood cells from haemopoietic tissue, as reflected in the decreases in mean corpuscular volume. Increases in red blood cells are attributed to an increase in the oxygen-carrying haemoglobin as an adaptation to altered respiratory homeostasis caused by copper and zinc. These increases are therefore a secondary reaction to the metals and not the result of direct stimulation of the haemopoietic tissue. In contrast, at an acidic pH copper and zinc concentrations usually caused blood alkalosis and decreases in white blood cell numbers, due to the bioconcentration of metals which blocks and suppresses the leucopoietic tissue. Decreases were also recorded in red blood cell counts, haemoglobin, haematocrit and mean corpuscular volume, which can be ascribed to anaemic and hypoxic conditions, gill damage and impaired osmoregulation.     

Heavy metals in relation to the biology of the mummichog, Fundulus heteroclitus

Heavy metal levels of cadmium, copper, mercury, manganese, and zinc were examined in the mummichog, Fundulus heteroditus from industrialized and non-industrialized environments. With one exception, the environment with the highest trace metal in its waters, had the fishes with the highest metal concentration. Except for mercury, the concentration factor varied inversely with the metal concentrations of the fish and water, suggesting a possible regulatory mechanism for metals in the tissues of mummichogs from environments with high metal concentrations. There was an inverse relationship between standard length and concentrations of zinc, manganese, copper and cadmium in whole male and female fishes. The viscera contained significantly greater concentrations of these metals than somatic muscle tissue. There were also significant differences between males and females with respect to whole-body zinc and copper concentrations, but no sex differences for manganese and cadmium.     

Uptake of six heavy metals by oat as influenced by soil type and additions of cadmium,lead, zinc and copper

Summary The influence of heavy metal additions on availability and uptake of cadmium, lead, zinc, copper, manganese and iron by oat was studied. The experiments were carried out as pot experiments using sandy loam, sandy soil and organic soil. Selective extractants were used to remove metals held in different soil fractions.Lead and copper were preferently bound by organics and oxides, zinc by oxides and inorganics, and cadmium by inorganics and organics.Addition of cadmium to the soils resulted in higher cadmium concentrations in all plant parts but lower concentrations of lead, zinc, copper, manganese and iron, and the accumulation indexes of these metals were also lower when cadmium was added to the soil.Addition of cadmium plus lead, zinc and copper resulted in higher cadmium concentrations in leaves and straw of plants grown in sandy loam and sandy soil, but lower concentrations when plants were grown in organic soil as compared with the results when cadmium was added separately. The transfer of cadmium, lead, zinc and copper from soil to plant was greatest from sandy soil, and zinc and cadmium were more mobile in the plant than were lead and copper.Cadmium concentrations in leaves correlated significantly with CaCl₂ and CH₃COOH extractions in sandy loam and sandy soil and with CH₃COOH extractions in organic soil.Generally, the total metal uptake was lowest from organic soil.     

An Ecological Risk Assessment of Air Emissions of Trace Metals from Copper and Zinc Production Facilities

Trace metals are components of releases to air emitted by copper and zinc production facilities in Canada. Six metals (copper, zinc, nickel, lead, cadmium, and arsenic) are examined as part of an overall environmental assessment of these releases. Estimates of metal deposition rates to soils and surface waters were derived from monitoring data in the vicinity of the production facilities and also through dispersion modelling studies. Fate and transport modelling of the metals deposited allowed an estimation of critical loads. Estimated annual deposition rates were compared with 25^th-percentile critical loads typically representative of effects on sensitive organisms under 25% of conditions in sandy soils or circumneutral to acidic lake waters. The results of the comparison suggest that there is a potential for adverse effects on aquatic and/or soil-dwelling organisms from exposure to steadystate concentrations of metals in the vicinity of copper and zinc production facilities. Approaches of particular significance in these assessments include probabilistic estimation of critical loads for metals, allowance for the speciation of metals defining the bioavailable fraction and limiting critical effect levels to the high end of natural background metal concentrations.     

Heavy-metal-induced proline accumulation and its role in ameliorating metal toxicity in Chlorella vulgaris

Exposure of Chlorella vulgaris to elevated concentrations of copper, chromium, nickel and zinc led to intracellular accumulation of high concentrations of these metals. Concomitantly, accumulation of free proline occurred, depending on the concentration of metals in the external medium or in the cell. The greater the toxicity or accumulation of a metal, the greater the amount of intracellular proline in algal cells. However, higher concentrations of copper and chromium were inhibitory to proline accumulation by the test organism. The accumulation of proline was triggered within a few hours of metal treatment. Test metals also induced lipid peroxidation; copper was the most efficient inducer whereas zinc was the least. Pretreatment of C. vulgaris with proline counteracted metal-induced lipid peroxidation and potassium ion efflux. Thus the present work shows a protective effect of proline on metal toxicity through inhibition of lipid peroxidation.     

The loss,uptake and tissue distribution of copper and zinc during the moult cycle in an ecological series of talitrid amphipods (Crustacea:Amphipoda)

The exuvial loss, subsequent uptake, and tissue and body distributions of the essential trace metals copper and zinc were investigated in an ecological series of talitrid amphipods, immediately after moult and throughout a post-moult period. Negligible quantities of copper or zinc were detected in cast exuvia of individual talitrids. Neither tissue nor whole body copper and zinc concentrations underwent significant changes during the moult cycle and all species showed extreme conservatism in their handling of body copper. There appeared to be no differential treatment of copper between species at the time of moult throughout the ecological series, with no obvious increase in copper retention by the more terrestrial species. The impact of moult cycle stage therefore is unlikely to affect the use of littoral talitrid amphipods as biomonitors for ambient copper and zinc concentrations.     

INTER- AND INTRASPECIFIC VARIATION OF MOSSES IN TOLERANCE TO COPPER AND ZINC

Bryophytes are often viewed as slowly evolving with little genetic variation within and among populations. A study of heavy-metal tolerance was initiated to test the capacity of bryophytes to undergo genetic differentiation in response to natural selection. Tolerance of Funaria hygrometrica to copper and zinc was greater in populations that originated on soil with high concentrations of these metals. Protonemal growth was more inhibited by the metals than was germination, and copper was more toxic than zinc. Zinc and copper tolerances were correlated, but so were the zinc and copper concentrations of native substrates. The pattern of population differentiation for heavy-metal tolerance in this species is much like that of flowering plants. Five populations of Physcomitrium pyriforme, which does not occur on metal-contaminated soil, were all highly tolerant of zinc but extremely intolerant of copper. This species seems to have an inherent tolerance to the former. Significant variation in tolerance to copper and zinc occurred among populations, but tolerance did not correlate with metal contents in native substrates. This pattern differs from that of flowering plants. Normal populations of species that colonize contaminated sites tended to be more tolerant than populations of species that do not colonize such sites. The extensive population differentiation in Funaria hygrometrica augments the evidence from electrophoretic data that there is genetic variation among populations of mosses and liverworts.     

Cadmium, copper and zinc in tissues of deceased copper smelter workers

Workers at a copper and lead smelter in northern Sweden have a multifactorial exposure to a number of heavy metals. The concentrations of cadmium, copper and zinc in liver, lung, kidney and brain tissues have been determined by atomic absorption spectrometry in 32 deceased long-term exposed male lead smelter workers, and compared with those of 10 male controls. Furthermore, copper and zinc levels in hair and nails were determined by energy-dispersive X-ray fluorescence.

The highest cadmium concentrations among both workers and controls were observed in kidney, followed in order by liver, lung and brain. The levels in kidney, liver and lung were all significantly higher in the workers than in the controls (p < 0.03). Among the workers relatively strong positive correlations (p < 0.03) were observed between cadmium concentrations in liver and lung, liver and kidney, liver and brain, and lung and brain. In the exposed workers a positive correlation was observed between cadmium and zinc concentrations in the kidney (r_s = 0.38; p = 0.034). This is probably mainly due to the protein metallothionein, which is stored in the kidney, binding equimolar amounts of these two metals.

The highest concentrations of copper were found in hair and nails among both workers and controls, followed in order by liver, brain, kidney and lung. The tissue concentrations of copper in brain, lung and kidney were all significantly higher among the smelter workers than in the controls (p ≤ 0.036). Copper levels in lung and age at time of death were positively correlated among the exposed workers (r_s = 0.39; p = 0.029). In the same group, positive correlations between copper and zinc concentrations in kidney (r_s = 0.45; p = 0.009) and nails (r_s = 0.68; p < 0.001) were also observed, reflecting possible biological interactions between these two metals.

Among both workers and controls, the highest zinc concentrations were found in hair, followed in order by nails, liver, kidney, brain and lung. Significantly higher tissue concentrations among the workers as compared with the reference group were noted in kidney, liver and brain (p ≤ 0.033).

Neither copper nor zinc concentrations in hair and nails seemed to provide a useful measure of the trace element status of the smelter workers.     

Biological effects of high copper and zinc concentrations and their interaction in rapeseed plants

In experiments with rapeseed (Brassica napus L., cv. Westar) plants, it was confirmed that copper was considerably more toxic than zinc. The toxic effects of 50 and 150 μM CuSO₄ were comparable to those of 1000 and 2500 μM ZnSO₄. The analysis of the effects of these concentrations of copper and zinc on photosynthetic pigment contents and on the rate of lipid peroxidation did not reveal any reasons for different toxicities of these heavy metals (HM). Among biological effects studied, significant differences were found in the organ distribution of these metals in plants grown on both the standard medium and the medium with high concentrations of copper or zinc. Copper retained in the roots in relatively small amounts and was poorly transported over the aboveground part of the plants. It stayed mainly in the lower leaves, and its distribution changed only a little during the recovery of plants following the HM treatment. In contrast, zinc proved to be highly mobile, it was concentrated in the upper leaves and actively transported when the plants were transferred to a medium with the optimal HM concentrations. High copper concentrations slowed strongly zinc uptake by the roots but practically did not change its movement over the plant. In contrast, high zinc concentrations facilitated copper uptake by the roots but reduced its transfer to the aboveground organs. The data presented here allow us to hypothesize that biological peculiarities of organ and cellular distribution of copper and zinc in plants and interaction of these HM play an important role in the toxic effects of high concentrations of these HM and the mechanisms of adaptation to them at industrial environmental pollution used by rapeseed plants.     

Reference ranges of copper and zinc and the prevalence of their deficiencies in an Arab population aged 15-80 years

Serum concentrations of copper and zinc were measured by flame atomic absorption spectrophotometry in 560 Kuwaitis aged from 15 to 80 yr who were in apparent good health to establish reference ranges and determine the prevalence of the deficiency of the trace metals. Zinc/copper ratios were derived by calculation. Because the mean +/- SD (microM) for copper in females (24.9 +/- 7) was significantly higher (p<0.0001) than in males (21.0 +/- 5.8) and vice versa for zinc (17.0 +/- 3.5 [males] vs 15.5 +/- 3.4 [females]) and zinc/copper ratios (0.87 +/- 0.28 [males] vs 0.67 +/- 0.27 [females]), gender-specific reference ranges were established in addition to reference ranges for the total population. The reference range for zinc was closer to those reported for other populations than was copper. Body mass index (BMI) and copper values were lower and the zinc/copper ratio was higher in the young (15-24 yr) compared to the older subjects. Copper concentrations were positively associated with BMI values (r=0.302, p<0.0001). Smokers had significantly lower (p=0.011) BMI than nonsmokers. The prevalence of copper and zinc deficiency, 0.36% and 0.53%, respectively, was low. Generally, the values for serum copper and zinc obtained for the Kuwaiti population studied suggest adequate dietary intake of the trace metals.     

Heavy metals in some Chinese herbal plants

The concentrations of nine heavy metals, cadmium, cobalt, copper, iron, manganese, nickel, lead, zinc and mercury in 42 Chinese herbal medicinal plants were determined. Generally, all the samples studied had, relative to the other trace metals, higher concentrations of iron, manganese, and zinc. The concentration range of the metals determined was comparable to that in many of the East Asian vegetables and fruits. A few samples were found to contain relatively higher concentrations of the toxic metals such as cadmium, lead, and mercury. This was probably caused by contamination during air-drying and preservation.     

Hepatic zinc,copper, and iron in the developing turkey embryo and newly hatched poult

The ontogeny of hepatic tissue growth and trace metal deposition was examined in the developing turkey embryo and newly hatched poult. Hepatic concentrations of zinc and iron in the embryo declined by about twofold between day 16 of incubation and hatching. Hepatic copper concentration increased approximately fourfold by day 23 of incubation and then declined rapidly through hatching. During the post-hatching period, hepatic zinc concentration increased twofold by day 10, whereas a small increase in hepatic iron concentration occurred just prior to hatching and continued through the third day post-hatching. A significant positive correlation existed between hepatic zinc and iron concentrations in the developing embryo. The concentrations of both these metals were inversely correlated with hepatic copper concentration during the same time. Total hepatic zinc and iron content increased throughout the entire time studied, whereas total copper content increased up to hatching and then declined during the first week post-hatching. The most rapid phase of hepatic metal accretion differed for each metal, with zinc being rapidly accumulated during the post-hatching period, copper during the last half of incubation and iron at about the time of hatching and the first few days post-hatching. Each of these metals demonstrated a specific relationship to hepatic tissue growth that changed between the embryonic and neonatal periods of development.     

The effects of cadmium and copper on the renal uptake and metallothionein binding of gold in the rat and hamster

Rats and hamsters, (pre)-treated with copper and cadmium, were used to investigate whether species-differences in renal metallothionein synthesis in response to gold were determined by changes in the kidney concentrations of other metals. The effects of both dietary copper limitation and excess on the renal metabolism of gold also were studied in the rat. In this species, all of the pre-treatments affected the renal concentrations of total and metallothionein-bound copper, but none of them altered either the kidney uptake or thionein-binding of gold. Incorporation of zinc into the metallothionein, which accompanied the binding of gold in this fraction of the kidney, however, was influenced slightly by the pretreatments. In hamsters, pretreatment with cadmium, which increased the concentrations of total and thionein-bound zinc in the kidneys, also did not affect the renal uptake of gold, although it increased significantly the binding of gold to the metallothionein fraction of the renal cytosol. This increased binding of gold also was accompanied by further increases in the zinc and copper contents of the metallothionein; the contents of total and thionein-bound cadmium, however, remained essentially unchanged. Concentrations of copper and zinc in the hamster kidney were not affected significantly by subcutaneous administration of copper alone (five daily doses, each of 3.2 mg Cu/kg body wt.), but were increased when gold was given during the copper-treatment. The concentrations of gold, copper and zinc in the renal metallothionein fraction also were increased under these conditions. From these results it seems that kidney metallothionein synthesis in response to gold may be related to the changes in either the concentration or distribution of zinc, rather than copper.     

Concentration of Selenium in Liver in Relation to Copper Level in Normal and Copper-Poisoned Sheep

Copper absorption, liver accumulation and development of copper toxicosis in sheep are influenced by a variety of other elements, in particular molybdenum, sulphur and zinc (Underwood 1977). In a previous study on liver concentrations of copper, molybdenum and zinc in normal and copper-poisoned sheep, no direct correlation was found between the concentrations of the three metals, but molybdenum was significantly lower in the livers from sheep dead from chronic copper poisoning than in normal animals (Frøslie & Norheim 1976).     

Trace metals in the benthic habitat of the Maarsseveen Lakes system,The Netherlands

The cadmium, zinc, lead and copper concentrations in benthic invertebrates and sediment were determined during two consecutive winters in the Maarsseveen Lakes system. A sequential extraction procedure was applied to estimate the bioavailability of the trace metals in the sediment. Based on the trace metal analyses of organisms and sediment, it is concluded that the Maarsseveen Lakes system has background levels of cadmium, zinc, lead and copper. As the majority of metals was present in geochemically more stable sediment phases, the sequential extractions provided limited additional information on trace metal bioavailability.