Selenium, Cadmium, Copper, and Zinc Concentrations in Sediments and Mullet (Mugil cephalus) from the Southern Basin of Lake Macquarie, NSW, Australia

Selenium, cadmium, copper, and zinc concentrations were measured in sediments and the tissues of mullet (Mugil cephalus) collected from the southern basin of Lake Macquarie, NSW, Australia. Trace metals in surficial sediments are enriched in trace metals relative to background concentrations (selenium, 3–19; cadmium, 14–42; copper, 1.5–3.6; zinc, 0.77–2.2 times background). Selenium, cadmium, and copper in Lake Macquarie mullet tissues are elevated compared to those in mullet collected from the Clyde River estuary, a relatively pristine location. Selenium and copper concentrations are also elevated compared to those reported in mullet tissues from other nonpolluted coastal environments. Zinc concentrations in Lake Macquarie mullet muscle tissues are significantly higher than those in muscle tissues of mullet from the Clyde River estuary, but mullet from both locations have similar zinc concentrations in other tissues. These results show that contamination of sediment with trace metals has resulted in elevated trace metals in the benthic feeding fish M. cephalus. Little of the variation of trace metal concentrations between fish was explained by variation in mass. Selenium concentrations in mullet are of concern in muscle tissues as they are above recommended acceptable limits for safe human consumption, while concentrations in tissues are at levels that may effect fish growth, reproduction, and survival. Copper concentrations in mullet tissues are also at levels that may reduce fish growth. Received: 11 September 1999/Accepted: 9 July 2000     

Environmental Geochemistry of Abandoned Flotation Tailing Reservior from the Tonglvshan Fe-Cu Sulfide Mine in Daye,Central China

This study investigated metals of tailings from Tonglvshan mine in Daye and assessed the effect of metal contamination in water and sediment near the tailing reservoir. The concentration of copper, lead, zinc, cadmium, chromium and nickel was measured in deposit samples taken from a profile in an abandoned flotation tailing reservoir, as well as in water and sediment samples near the reservoir. The results of this study indicate that copper concentration ranges from 780 to 4390 mg/kg, 2–10 times higher than the limit values in soil, while the contents of other metals are below the limit values. Metal levels in water and sediments are high and varied widely in different sampling sites. The mean concentrations of copper, lead, zinc, cadmium, chromium and nickel in waters are 27.76, 2.28, 8.20, 0.12, 5.30 and 3.04 mg/L, while those in sediments are 557.65, 96.95, 285.20, 0.92, 94.30 and 4.75 mg/kg, respectively. All of the results indicate that the environment near the tailing reservoir is polluted to some extent by some kinds of metals, especially by copper, lead, zinc and cadmium, which may be caused not only by some discharge sources of metals, but also by life garbage and sewage.     

Investigation of Zinc,Copper, Lead and Cadmium Accumulation in the Tissues of <Emphasis Type="Italic">Sander lucioperca</Emphasis> (L., 1758) Living in Hirfanlı Dam Lake,Turkey

This study, some metals (zinc, copper, lead and cadmium) were analyzed in liver, muscle and gills of Sander lucioperca (Linnaeus, 1758) caught from the Hirfanlı Dam Lake in December 2007. The highest concentrations were found in liver (zinc:32.5 μg/g, lead:10.73 μg/g, copper:5.85 μg/g, cadmium:0.76 μg/g) of Sander lucioperca. It was seen that the accumulation of zinc, lead and cadmium primarily took place in liver followed by muscles and gills. It was observed that copper is mainly accumulated in liver followed by gill and mucsles.     

Changes in Selenium, Copper, Cadmium, and Zinc Concentrations in Mullet (Mugil cephalus) from the Southern Basin of Lake Macquarie, Australia, in Response to Alteration of Coal-Fired Power Station Fly Ash Handling Procedures

Selenium, copper, cadmium, and zinc concentrations were measured in mullet (Mugil cephalus) from the southern basin of Lake Macquarie, Australia, in 1997 to determine if improved ash-handling practices at an adjacent coal fired power station, implemented in 1995, had significantly lowered trace metal concentrations in mullet tissues. Mean muscle tissue concentrations of selenium (5.9 ± 0.7 μg/g dry mass), copper (3.6 ± 0.1 μg/g dry mass), and zinc (14 ± 1 μg/g dry mass) are lower than previously reported for mullet analyzed in 1993 (10 ± 2, 21 ± 3, 27 ± 3 μg/g dry mass, respectively). Cadmium concentrations in liver tissues increased from 2.3 ± 0.3 to 6 ± 2 μg/g dry mass. Significant intra-tissue correlations between metal concentrations were found for all tissues except muscle. Strong correlations of selenium, copper, and zinc concentrations were found in liver tissues, indicating a common primary source may exist for these metals, such as fly ash. All trace metals were found to have significant inter-tissue correlations, with strong correlations occurring for selenium between all tissues and for cadmium between all tissues except muscle. Regulation of copper, cadmium, and zinc appears to be occurring in muscle tissue. Selenium concentrations in mullet are still above levels considered to be of concern to human consumers. Trace metal concentrations are below that known to effect the health of fish. Mullet are directly exposed to trace metal concentrations as a result of feeding and the ingestion of contaminated sediment and detritus. Lower metal concentrations found in mullet tissues are attributed to the burial of highly contaminated sediment with material containing lower trace metal concentrations. Little of the variations in trace metal concentrations between mullet was explained by mass, gender, or age. Received: 20 August 2000/Accepted: 22 February 2001     

The Effect of pH on the Uptake and Toxicity of Copper and Zinc in a Tropical Freshwater Alga (Chlorella sp.)

Copper and zinc toxicity to the freshwater alga Chlorella sp. was determined at a range of pH values (5.5–8.0) in a synthetic softwater (hardness 40–48 mg CaCO₃/L). The effects of the metals on algal growth (cell division) rate were determined after 48-h exposure at pH 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0. The toxicity of both metals was pH dependent. As pH decreased from 8.0 to 5.5, the copper concentration required to inhibit the algal growth rate by 50% (IC50) increased from 1.0 to 19 μg/L. For zinc, the IC50 increased from 52 to 2700 μg/L over the same pH range. Changes in solution speciation alone did not explain the increased toxicity observed as the pH increased. Modelled Cu²⁺ and Zn²⁺ concentrations decreased with increasing pH, whereas toxicity was observed to increase. Measurements of extracellular (cell-bound) metal concentrations support the biotic ligand model (BLM) theory of competition between protons (H⁺) and metals for binding sites at the algal cell surface. Higher extracellular metal concentrations were observed at high pH, indicating reduced competition. Independent of pH, both extracellular and intracellular copper were directly related to growth inhibition in Chlorella sp., whereas zinc toxicity was related to cell-bound zinc only. These findings suggest that the algal cell surface may be considered as the biotic ligand in further development of a chronic BLM with microalgae. Conditional binding constants (log K) were determined experimentally (using measured intracellular metal concentrations) and theoretically (using concentration-response curves) for copper and zinc for Chlorella sp. at selected pH values. Excellent agreement was found indicating the possibility of using concentration-response data to estimate conditional metal-cell binding constants.     

Acute Toxicity of Aqueous Copper,Cadmium, and Zinc to the Mayfly <Emphasis Type="Italic">Rhithrogena hageni</Emphasis>

Heptageniid mayfly nymphs have been suggested as sensitive indicators of metal contamination in streams based on biomonitoring studies, experimentation in situ, and experimentation in microcosm. Laboratory tests were conducted to evaluate the sensitivity of Rhithrogena hageni, a heptageniid mayfly, to waterborne copper, cadmium, and zinc. Tests were conducted with soft water (hardness = 40–50 mg/L) at about 12°C. Toxicity endpoints were survival and moulting (%/day). Median 96 hr lethal concentrations were 0.137, 10.5, and 50.5 mg/L for copper, cadmium and zinc, respectively. The average daily moulting rate of survivors significantly decreased after exposure to these metals in solution.     

Estimation of Target Hazard Quotients and Potential Health Risks for Metals by Consumption of Seafood in Taiwan

The purpose of this paper is to describe the impact of metal pollution on the main seafood and assess the potential health risk from consuming the contaminated seafood in Taiwan. The results of geometric mean (GM) metal concentrations in various seafood showed that the copper, zinc, and arsenic concentrations in oysters were significantly (p < 0.001) higher than those in the other seafood by about 1,057, 74.3, and 56.2 times, respectively. The green color found in the oysters was due to high GM copper and zinc concentrations of 909 (ranging from 113–2,805) and 1,293 (ranging from 303–3,593) μg/g dry wt, respectively. In addition, using a maximum consumption rate of 139 g/day of oysters for individuals, calculations yield target hazard quotients (daily intake/reference dose) of below 1 for cadmium and mercury and high values of 1.61, 9.33, and 1.77 for inorganic arsenic, copper, and zinc in adults, respectively. The various lifetime cancer risks for inorganic arsenic (maximum exposed individuals risk ranging from 9.93 × 10⁻⁶ to 3.11 × 10⁻⁴) might be caused by consuming different seafood in Taiwan. The highest risk estimate for inorganic arsenic was 5.10 × 10⁻⁴ for consumption of oysters by Machu Islands residents. The long-term exposure of metals through consumption of oysters, especially for some high-risk groups, could be dangerous. Taking inorganic arsenic for example, a 10⁻⁶ upper limit on lifetime risk as the health protection standard would require maximum oyster residue levels of approximately 0.0076–0.056 μg/g wet wt, for consumption rates of 139–18.6 g/d. In the light of known risks to public health, the government should issue an immediate warning to the public to refrain from eating all seafood harvested from the Taiwan coastal areas, especially the Hsiangshan area and the Machu Islands. Received: 18 January 1998/Accepted: 6 July 1998     

Toxicity of metal mixtures to a tropical freshwater alga (Chlorella sp): the effect of interactions between copper,cadmium, and zinc on metal cell binding and uptake

The individual and combined effects of copper, cadmium, and zinc on the cell division rate of the tropical freshwater alga Chlorella sp. were determined over 48 to 72 h. Metal mixtures were prepared based on multiples of their single-metal median effective concentration (EC50) values, i.e., toxic units (TU) using a triangular mixture design with five toxicant levels (0, 0.75, 1.0, 1.25, and 1.5 TU). Single-metal EC50 values after a 72-h exposure were 0.11, 0.85, and 1.4 microM for copper, cadmium, and zinc, respectively. Significant interactions were observed for all metal combinations after 48 and 72 h. An equitoxic mixture of Cu + Cd was more than concentration additive (synergistic) to the growth of Chlorella sp., while combinations of Cu + Zn, Cd + Zn, and Cu + Cd + Zn were all less than concentration additive or were antagonistic. To determine the effect of each metal on the uptake of the other, extracellular (membrane-bound) and intracellular metal concentrations, both alone and in mixtures, were compared. The increased growth inhibition observed for mixtures of Cu + Cd was due to higher concentrations of cell-bound and intracellular copper in the presence of cadmium compared with copper alone (i.e., cadmium-enhanced copper uptake). In contrast, both extra- and intracellular cadmium concentrations were reduced in the presence of copper. In mixtures of Cu + Zn, copper also inhibited the binding and cellular uptake of zinc, which resulted in decreased toxicity. Zinc had no appreciable effect on the uptake of copper by Chlorella sp. Our results suggest that all three metals share some common uptake and transport sites on Chlorella cells and that copper out competes both cadmium and zinc for cell binding. Determination of metal cell distribution coefficients (K(d)) confirmed that K(d) values for cadmium and zinc in single-metal exposures decreased in the presence of copper.     

Distribution of Heavy Metal Residues in Fish from the River Nile Tributaries in Egypt

The distribution patterns of some metals (zinc, iron, copper, cadmium and lead) in fish samples collected from El Menofiya Governorate, Egypt were studied. The samples were collected from El Menofiya, canal water supplies (El Sarsawia, El Bagoria and Bahr Shebin), in addition to El Embaby, El Menofi and Miet Rabiha drainage canals each 2 month during periods of 16 month, June 2007–Septemper 2008. In the present investigation, the high concentrations of metals were found in fish samples collected from the drainage canal. The highest mean concentration of lead (1.864 μg/g), copper (1.495 μg/g) and cadmium (1.840 μg/g) were found in fish samples collected from El-Embaby drain. While the highest mean concentration of iron (108.26 μg/g) and zinc (24.35 μg/g) were present in fish samples collected from Miet-Rabiha drain. Lead and cadmium were found in higher concentration than those recommended by FAO for fish.     

Phytoextraction Potential of <Emphasis Type="Italic">Prosopis juliflora</Emphasis> (Sw.) DC. with Specific Reference to Lead and Cadmium

Root and shoot samples of Prosopis juliflora were assessed for their heavy metal content to evaluate the species as a green solution to decontaminate soils contaminated with lead and cadmium. The highest uptake of both the metals was observed in plants from industrial sites. Sites with more anthropogenic disturbance exhibited reduced chlorophyll levels, stunted growth, delayed and shortened reproductive phase. The ratios of lead and cadmium in leaves to lead and cadmium in soil were in the range of 0.62–1.46 and 0.55–1.71, respectively. Strong correlation between the degree of contamination and concentrations of lead and cadmium in plant samples identifies P. juliflora as an effective heavy metal remediator coupled with environmental stress.     

Metals in the Surface Sediments of Selected Water Reservoirs, Slovakia

Ruzin and Velke Kozmalovce water reservoirs (Slovakia) receive potentially toxic elements through rivers draining catchment areas polluted with the former extensive mining of ore-bearing deposits. In this study, the concentrations and fractionation of metals (antimony, arsenic, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, vanadium and zinc) have been studied in the surface sediments of the two water reservoirs. Comparison of metal concentrations found in the sediments with the mean shale values revealed a significant anthropogenic enrichment mostly with antimony (22.7), copper (8.5), zinc (5.5), cadmium (4.7), mercury (4.7), arsenic (4.5) and lead (3.9), and antimony (9.8), cadmium (8.8), zinc (4.9), lead (3.3) and arsenic (3.1) in the Ruzin and Velke Kozmalovce reservoirs, respectively. The results of fractionation study showed that the major proportion of cadmium (44.9–52.6%), cobalt (35.7–58.3%) and zinc (27.8–48.7%) was found in labile fractions, i.e., water- and acid-soluble fractions, although copper and nickel exhibited also significant labile fractions. When the risk assessment code was applied to the fractionation study, cadmium and cobalt came under high and very high risk category for the environment, and therefore might cause adverse effect to aquatic life.     

Induced Metal Tolerance in Microbenthic Communities from Three Lowland Rivers with Different Metal Loads

The response of microbenthic communities to sustained metal stress was studied in three lowland rivers with different levels of pollution. Tolerance against zinc and cadmium was determined in short-term toxicity tests with microbenthic assemblages colonizing glass discs. Photosynthetic activity served as an endpoint in tests for algae, whereas for bacteria thymidine incorporation was determined. For bacterial assemblages from unpolluted locations, EC₅₀ values in short-term tests ranged between 6.7 and 56.2 μM zinc, and 8.7 and 25.5 μM cadmium, respectively. Bacterial assemblages from the two most polluted sites were significantly more tolerant for zinc (EC₅₀: 994 μM and >1,000 μM) and cadmium (EC₅₀: 218 μM and 154 μM). Results indicated a shift in community composition toward pollution-adapted organisms when a threshold concentration of 1 μM zinc is exceeded. Although an increasing community tolerance was also indicated for algae, EC₅₀ values for microbenthic algae from all sites exceeded in most cases the highest metal concentrations tested (Zn: 1,000 μM; Cd: 320 μM). Since species composition of algal assemblages was found to change at much lower metal levels, it is concluded that short-term toxicity tests measuring photosynthesis inhibition do not reflect well the long-term effects of these metals. Toxic effects of metals on both algal and bacterial assemblages are attenuated by precipitation and complexing capacities of the biofilm. Received: 9 June 1998/Accepted: 6 December 1998     

Bioaccumulation of Heavy Metals in Freshwater Fish Species,Anzali, Iran

The main objectives of study were to monitor the metals concentrations, in freshwater fish species, Carassius gibelio and Esox lucius; and to identify any relationships between species and bioaccumulation of metals. The highest concentration of metals (cadmium, 1.96; copper, 24.2; zinc, 49.6; lead, 5.4; chromium, 4.4) between the fish species and tissues was in the liver of Esox lucius, while the lowest (cadmium,0.21; copper,7.2; zinc,19.4; lead,0.9; chromium,0.6 μg/g) found in the muscle of Carassius gibelio. Results showed that the metal concentrations were in fishes in descending order of zinc > copper > lead > chromium > cadmium, similarly in the tissue liver > kidney > gill ~ intestine > muscle.     

Heavy Metal Concentrations in Feathers of Korean Shorebirds

This study presents concentrations of zinc, manganese, copper, lead, and cadmium in the feather of five shorebird species from Yeongjong Island, Korea in the East Asian–Australian migration flyways. The objectives of this study were to determine levels of heavy metal concentrations in the feathers of shorebirds, to evaluate the pattern of heavy metal concentrations in the feather and the liver, and to examine the correlation between heavy metal concentrations in the feathers and livers. We hypothesized that difference of heavy metal concentrations will show by the breeding ground of shorebirds. Lead concentrations in dunlins (geomean = 14.8 μg/g wet weight) and great knots (20.8 μg/g wet weight) feathers were significantly higher than Terek sandpipers (3.32 μg/g wet weight); other metals were not different among shorebirds. Zinc, lead, and cadmium concentrations in the feather were correlated with the liver concentrations, but manganese and copper concentrations were not. Zinc, manganese, copper, lead, and cadmium concentrations in the feather from this study were within the range of earlier studies for wild birds, but cadmium concentrations in dunlins were higher than other studies. Because lead concentrations in livers and feathers of the Terek sandpiper were lower than in other shorebirds, we suggest that Terek sandpipers were exposed to lower lead concentrations than Kentish plovers, dunlins, and great knots on their breeding ground. An erratum to this article can be found at     

Copper, zinc, and cadmium concentrations in Peromyscus maniculatus sampled near an abandoned copper mine

Concentrations of zinc, copper, and cadmium were determined in soil and liver, kidney, bone and stomach contents of deer mice (Peromyscus maniculatus) from two sites near an abandoned mine and one control site, on Vancouver Island, British Columbia, Canada. Soil concentrations of copper were significantly elevated at the mine and off site vs the reference site. In contrast, there was no difference in soil cadmium and zinc concentrations between the mine and reference site. Concentrations of copper, cadmium and zinc in livers of mice from the mine site were significantly elevated relative to the reference and off site locations. Cadmium kidney concentrations tended to be greater in mice from the mine versus the off site and reference site. No differences in bone cadmium, copper and zinc and, kidney copper and zinc concentrations were noted among mice from the three locations. Diet of mice from mine and off sites contained significantly greater copper concentrations than the reference population; no differences in cadmium or zinc diet concentrations in mice from the three sites were noted. Comparison of ratios of metal concentrations in diet:soil and concentrations in liver:soil suggest that for zinc and copper, soil and diet are of equal importance as a source of metal contamination to these mice. In contrast, cadmium diet:soil and cadmium liver:soil ratios were much greater than one indicative of bioconcentration of cadmium from soil to diet and from soil to liver. For assessing routes of metal exposure, in this case for deer mice inhabiting an abandoned mine site, for copper and zinc, soil will most likely be indicative of exposure conditions. In contrast, concentrations of cadmium in diet will be more representative of amounts that the animal is potentially ingesting. Of further importance is that relative to reference sites, mice inhabiting an abandoned copper mine site have significantly elevated tissue levels of copper. This is turn will provide a route of metal exposure to canivorous birds such as owls and hawks. The toxicological significance of this exposure to birds of prey has yet to be assessed adequately.     

Seasonal Accumulations of Some Heavy Metal in Water,Sediment and Tissues of Black-Chinned Tilapia <Emphasis Type="Italic">Sarotherodon melanotheron</Emphasis> from Biétri Bay in Ebrié Lagoon,Ivory Coast

The seasonal accumulation of cadmium, copper, lead, mercury and zinc was determined in sediments, water, and black-chinned tilapia (Sarotherodon melanotheron; muscle, brain, kidney and liver tissues) collected monthly from Biétri Bay. The mean water concentration of metals (in mg L⁻¹) ranged from 0.01 to 0.30 (mercury), 0.02–0.26 (cadmium), 2.40–4.80 (lead), 9.05–9.68 (copper), and 12.05–19.87 (zinc). The seasonal variations showed a significant difference in the levels of mercury, cadmium and lead among season. The highest mercury (0.30 ± 0.02 μg L⁻¹), cadmium (0.26 ± 0.02 mg L⁻¹) and lead (4.80 ± 1.03 mg L⁻¹) levels were observed during dry season, while the lowest levels (0.21 ± 0.01, 0.02 ± 0.01 and 2.40 ± 0.02 mg L⁻¹, respectively mercury, cadmium and lead) were measured during rainy season. The average cadmium (0.58 ± 0.36 mg L⁻¹), copper (42.15 ± 19.40 mg L⁻¹), lead (58.47 ± 38.10 mg kg⁻¹), mercury (0.79 ± 0.47 μg kg⁻¹) and zinc (187.58 ± 76.99 mg kg⁻¹) concentrations determined in Biétri Bay sediments showed a similar trend as in water. The seasonal variations of mercury, cadmium and lead in tissues revealed that these metals were higher concentrated during dry and swelling seasons. The levels of zinc and copper followed by lead were higher in the tissues. The order of tissues metals concentrations was: kidney > liver > brain > muscle.     

Metals in Laysan Albatrosses from Midway Atoll

We examined the concentrations of lead, cadmium, selenium, chromium, manganese, arsenic, tin, and mercury in the heart, liver, kidney, salt gland, and feathers of adult (n = 10) and young (n = 15) Laysan albatrosses (Diomedea immutabilis) from Midway Atoll in the north-central Pacific Ocean. Lead poisoning has been reported in some Laysans nesting near buildings on Midway, but other heavy metals have not been examined. We examined tissue distribution of metals by age and gender (adults only). We also examined tissue concentrations in three birds with a droop-wing syndrome characteristic of lead poisoning. We compared metal levels in salt gland (a special excretory organ of marine birds) with those in other tissues. All metals varied significantly across tissues in both adults and chicks, and the relative tissue concentrations were similar in adults and chicks for most metals. Adults had higher levels of most metals in most organs, with significant differences mainly for cadmium (up to 20× higher in kidney and salt gland) and for mercury (17× higher in kidney). However, chicks had significantly higher manganese in liver and arsenic in salt gland. The salt gland had concentrations of most metals (except cadmium, selenium, and mercury) comparable to the kidney levels, which is consistent with it serving as an excretory organ for the cations. Chicks with droop-wings had very elevated levels of lead in their tissue (16.8 ppm in feathers, 14 ppm in liver and kidney), whereas levels of other metals were not significantly different from the apparently normal chicks. Received: 1 April 1999/Accepted: 29 June 1999     

Uptake and Elimination of Cadmium and Zinc by Eisenia andrei During Exposure to Low Concentrations in Artificial Soil

Bioaccumulation factors (BAFs) are often used in the risk assessment process to estimate trophic transfer of contaminants such as metals from soil. BAFs can be derived from laboratory studies through the determination of steady-state concentrations or kinetic estimation methods. In this study, bioaccumulation tests were performed with artificial soil spiked at low levels with cadmium or zinc to determine uptake and elimination kinetics of both metals by the compost worm Eisenia andrei. The metal-amended soils were acclimated for 21 days prior to the test, after which worms were individually incubated in the soils. The uptake phase comprised 0–21 days, after which the test organisms were transferred into clean soil and the elimination phase continued for an additional 21 days. Subsamples of soil and earthworms (whole body) were collected from independent replicates throughout the uptake phase and elimination phase and analyzed for total metal concentrations. Uptake of Cd in E. andrei increased linearly with time and did not reach steady state within the testing period. Cd uptake and excretion were described by a one-compartment first-order kinetics model. Zn concentrations rapidly increased in E. andrei after 1 day of exposure but subsequently decreased to background levels throughout the remainder of the uptake phase; internal Zn concentrations did not change from background levels during the elimination phase. Kinetic BAFs were calculated for Cd and Zn. Cd is a nonessential metal that is bioaccumulated at a relatively rapid rate, while Zn is an essential metal, and as such, it is regulated by E. andrei. Metal essentiality and concentration significantly impact bioaccumulation of metals by terrestrial invertebrates.     

Elemental Composition and Sources of Fine Particulate Matter (PM2.5) in Delhi,India

It is essential to understand the occurrence from and plant bioavailability of soil microplastics to heavy metals in soils to assess their environmental fate and risk. The purpose of this study was to evaluate the effect of different microplastic concentrations on the bioavailability of copper and zinc in soil. The relationship between the availability of heavy metals in soil assessed by chemical methods (soil fractionation) and the bioavailability of copper and zinc assessed by biological methods (accumulation in maize and cucumber leaves) in relation to the concentration of microplastics. The results showed that copper and zinc in soil shifted from stable to effective fraction with increasing polystyrene concentrations, which would increase the toxicity and bioavailability of heavy metals. When the concentration of polystyrene microplastics increased, copper and zinc accumulation in plants increased, chlorophyll a and chlorophyll b decreased, and malondialdehyde increased. It is shown that the addition of polystyrene microplastics promoted the toxicity of copper and zinc and inhibited plant growth.

     

Leaching of Heavy Metals from Artificial Soils Composed of Sewage Sludge and Fly Ash

The purpose of this study was to determine the leaching characteristics of heavy metals from artificial soils composed of sewage sludge and fly ash. A leaching experiment was carried out over a period of 90 days. The leachates from artificial soils were collected every 15 days, and the concentrations of cadmium, lead, copper, zinc, chromium, and nickel in leachates were determined. Results showed that pH values of the artificial soils leachate were stable, ranging from 6.71 to 7.62 at the end of the experiment. Except of the cadmium, the concentrations of chromium, nickel, and copper in leachates of the artificial soils reached a stable level at the end of the experiment. The final concentrations of copper in leachates varied from 27.1 to 127.5 μg L⁻¹, which was lower than European threshold value for drinking water, (1,000 μg L⁻¹), while final nickel and chromium concentrations in leachates exceeded the European threshold ones. Amorpha fruticosa and Robina pseudoacacia grown in the artificial soils had different effects on cadmium, nickel, chromium, and copper leaching behavior. Amorpha fruticosa resulted in higher Ni and Cu concentrations in leachates, while Robina pseudoacacia enhanced leaching concentration of Cr.