Cadmium and Lead Accumulation in Three Endogeic Earthworm Species

The objective of this study was to assess the capability of earthworms from the same ecological group as heavy metal bioindicators. Three earthworm species from the endogeic group were studied: Aporrectodea caliginosa (Savigny, 1826), Perelia kaznakovi (Michaelsen, 1910) and Octolasion lacteum (Örley, 1885). Their accumulation of the heavy metals lead (Pb) and cadmium (Cd) were studied from three stations in Tehran province, Iran. O. lacteum was used to compare metal accumulations in two sites located next to a highway. A. caliginosa and P. kaznakovi were used at a third site located near the edge of a sewage system to compare metal accumulations between the two endogeic species in this area. At both locations, the concentrations of Cd and Pb in earthworms were higher than in the surrounding soil. The results of the study revealed that P. kaznakovi and A. caliginosa were better bioindicators for Pb, but O. lacteum was a better bioindicator for Cd. These earthworms can therefore be used as Cd and Pb bioindicators in environmental assessment.     

Use of organic amendments as a bioremediation strategy to reduce the bioavailability of chlorpyrifos insecticide in soils. Effects on soil biology

The sorption capacity of both an organic municipal solid waste by-product (MSW) and a cow manure (CM) in a soil polluted with chlorpyrifos, as well as its effect on soil microbial activity, and weight, reproductive parameters and glutathione-S-transferase activity of two earthworm species (Eisenia fetida and Lumbricus terrestris) were studied. Chlorpyrifos was added at the recommended application rate (5 L ha⁻¹; 768 mg chlorpyrifos kg⁻¹) and treated with MSW at a rate of 10% and CM at a rate of 5.8% in order to apply the same amount of organic matter to the soil. An unamended polluted soil was used as control. Earthworm cocoon number, average weight of cocoon, and number of juveniles per cocoon were measured after 30 days of incubation, whereas soil enzymatic activities, earthworm weight, and glutathione-S-transferase activity of earthworms were measured after 3, 45 and 90 days. Soil enzymatic activities, reproductive and glutathione-S-transferase activity in both worms decreased in polluted soil. The inhibition percentage of soil enzymatic activities, reproductive and glutathione-S-transferase activity in both worms was lower in MSW-amended soil than for CM-amended soil. The toxic effect of chlorpyrifos on E. fetida was lowest compared to L. terrestris. This suggested that the addition of organic wastes with higher humic than fulvic acid concentration is more beneficial for remediation of soils polluted with chlorpyrifos.     

Remediation of heavy metal-contaminated soils using phosphorus: evaluation of bioavailability using an earthworm bioassay

This study investigated the effectiveness of phosphorus (P) as an in situ remediation technique in site soils collected from the Tri-State mining area. The site soils were treated with two different types (KH₂PO₄ and Super Triple Phosphate fertilizer) and levels (600 and 5,000 mg/kg) of phosphorus. A toxicokinetic approach was used to determine whether phosphorus amendments reduced heavy metal bioavailability to the earthworm Eisenia fetida. Bioaccumulation factors were used as a measure of bioavailability. Depuration patterns of lead, zinc, and cadmium also were studied after removing earthworms from contaminated soils and then placing them in noncontaminated artificial soil. Results showed that the high phosphorus treatments significantly reduced lead, zinc, and cadmium bioavailability to the earthworms, probably due to formation of metal-phosphate complexes in the soils. Results also indicated that other soil characteristics in addition to amended phosphorus have an affect on bioavailability. Depuration experiments showed a biphasic elimination pattern for each metal. The current results indicate that phosphorus soil amendments may reduce ecological risk to soil-inhabiting invertebrates exposed to heavy metal-contaminated soils. Received: 19 November 2001/Accepted: 13 April 2002     

Application of Plant and Earthworm Bioassays to Evaluate Remediation of a Lead-Contaminated Soil

Earthworm acute toxicity, plant seed germination/root elongation (SG/RE) and plant genotoxicity bioassays were employed to evaluate the remediation of a lead-contaminated soil. The remediation involved removal of heavy metals by a soil washing/soil leaching treatment process. A portion of the soil after remediation was rinsed with water in order to simulate exposure to rainfall. The bioassay results showed that the soils before treatment (BT) and after treatment plus water rinsing (RT) were not toxic to earthworms in a 14-day exposure, while after treatment (AT) showed significant toxicity. The LC50 values for Eisenia fetida and Lumbricus terrestris were 44.04 and 28.83 (as % AT soil supplemented in artificial soil), respectively. The phytotoxicity data indicated that all three test soils significantly inhibited lettuce SG/RE in a dose-related manner, with AT being the most phytotoxic. In oats, RT had no effect on SG/RE and AT was more toxic than BT. For the two local site grass seeds tested (blue grama and sideoat grama), the AT soil was the most phytotoxic followed by BT and RT. In Allium cepa (common onion), BT and AT induced similar levels of genetic damage to root tip cells, whereas RT was not genotoxic. High salt levels generated during the remediation process appeared to be responsible for the increased toxicity of AT soil for both plants and earthworms. The rinsing of the AT soil with water effectively removed both acutely toxic and genotoxic components of the soil. Received: 20 May 1996/Revised: 7 August 1996     

Using earthworms to test the efficiency of remediation of oil-polluted soil in tropical Mexico

This study focuses on the medium-term effects of soil bioremediation on mortality and reproduction rates of Eisenia fetida (laboratory experiment) and of the tropical earthworm Polypheretima elongata (field experiment). We compared soils restored with the two bioremediation technologies landfarming (LF) and compost-bioremediation (BI) with control soils and with soils contaminated with 1% and 2% of petroleum. Control and restored soils both were fertile and showed low hydrocarbon contents. The mortality of E. fetida was not influenced by soil restoration and by contamination with 1% petroleum; it only increased in soils contaminated with 2% petroleum. However, the reproduction rate of E. fetida was significantly lower in the soils restored with LF and in those contaminated with 1% crude oil and significantly higher in the soils restored with BI. P. elongata showed the same reaction as E. fetida. We conclude that it is important to include reproduction or other sub-lethal tests for earthworms when estimating the efficiency of restoration techniques.     

Toxicity Assessment of Two Soils from Jales Mine (Portugal) Using Plants: Growth and Biochemical Parameters

Contaminants in soils can enter food chains through primary producers. Bioavailable contaminants can induce growth, and reproductive or biochemical changes in plants. To evaluate the bioavailability of heavy metals in two soils from Jales mine surroundings, bioassays with the plants Brassica rapa (RCBr) and Avena sativa were performed. Biochemical parameters (protein and malondialdehyde [MDA] content, and catalase and peroxidase activities) were also measured. The soils had different heavy metal contents: JNC soil contained low heavy metal concentrations, whereas JC soil had high heavy metal contents. Results stressed the difference between species sensitivity, with A. sativa showing no toxicity effects when exposed to both soils. On the other hand, B. rapa presented a decrease in growth parameters when exposed to JNC soil and no changes when exposed to JC soil. A Life Cycle Bioassay confirmed this trend for B. rapa exposed to JNC soil, but also evidenced that JC soil was affecting B. rapa in terms of flower and seed pod production. Biochemical assays showed that plants affected by heavy metals also displayed oxidative stress, with an increase in MDA production, reduction of protein content, and reduction of catalase and peroxidase activities. All bioassays revealed that JNC soil, although with a lower heavy metal content, had a higher bioavailable fraction when compared to JC soil, which consequently increased its toxicity to plants.     

Utility of Caenorhabditis elegans for Assessing Heavy Metal Contamination in Artificial Soil

There is an increasing need for the development of soil bioassay protocols. Currently the only internationally standardized soil test organism is the lumbricid earthworm Eisenia fetida. Many alternate soil test organisms have been proposed. This work compares Caenorhabditis elegans to several other test organisms, including E. fetida, for heavy metals in soil. In this evaluation, such factors as ease of testing and culturing, duration of testing, soil volume needed, and the sensitivity of the organism were considered. Results show that C. elegans is more sensitive than most other organisms evaluated and is similar in response to E. fetida. The second issue compares C. elegans LC₅₀ values to heavy metals criteria specified in the US EPA regulations for land application of sewage sludge. Currently, the regulations are set on total metals in the soil and do not consider bioavailability of the metals. Regulations do not consider soil physiochemical properties, such as organic matter content, clay content, and cation exchange capacity, which have been shown to affect the availability of metals to soil organisms. While the C. elegans LC₅₀ values are above standard values in artificial soil, work in our lab indicates that the LC₅₀s are below regulation values for other soil types. Due to the ease of culturing and testing, good sensitivity, along with the wealth of biological information and ecological relevance, C. elegans is a good organism for use in soil bioassays. Received: 2 June 1999/Accepted: 13 January 2000     

Development of a standardized reproduction toxicity test with the earthworm species Eisenia fetida andrei using copper, pentachlorophenol and 2,4-dichloroaniline

This article describes a standardized test method for determining the effect of chemical substances on the reproduction of the earthworm Eisenia fetida andrei. It is based on the existing guidelines for acute toxicity testing with earthworms, and for reasons of standardization the same artificial soil substrate and earthworm species were chosen as prescribed by these guidelines. After being preconditioned for one week in untreated soil, earthworms are exposed to the chemical substances for 3 weeks. The number of cocoons produced is determined, and cocoons are incubated in untreated artificial soil for 5 weeks to assess hatchability. Results are presented from toxicity experiments with pentachlorophenol, copper, and 2,4-dichloroaniline. For these compounds no-effect levels (NEL) for cocoon production were 32, 60-120, and 56 mg.kg-1 dry soil, respectively. Hatching of cocoons was influenced by pentachlorophenol (NEL, 10 mg.kg-1), but not by copper and dichloroaniline. Following exposure, earthworms were incubated in clean soil again to study the possibility of recovery of cocoon production. For copper and dichloroaniline earthworms did recover cocoon production to a level as high as the control level or even higher; in case of pentachlorophenol, cocoon production was still reduced after 3 weeks in clean soil.     

Distribution of Arsenic and Trace Metals in the Floodplain Agricultural Soil of Bangladesh

Arsenic contaminated groundwater of Bangladesh is one of the largest natural calamities of the world. Soil samples were collected from floodplain agricultural land of Faridpur and Dhamrai regions to estimate the concentration of arsenic and other trace metals (copper, nickel, zinc, chromium, cadmium, lead, selenium, cobalt, mercury, and manganese). Average arsenic in Faridpur soil was recorded more than three times higher than the world limit and nearly five times higher than that of Dhamrai. The average copper, chromium and cobalt both in Faridpur and Dhamrai agricultural soil were also higher than the Dutch and the world standards. Both Fardipur and Dhamrai soil contain low amount of selenium in comparison to world limit (0.7 mg kg⁻¹). A poor correlation between manganese and arsenic was noticed in Faridpur. This may be played a subordinate role in the fixation of arsenic in soil. This study also reveals that the area which has arsenic and trace metal contaminated groundwater may also contain high level of arsenic and trace metals in the agricultural soil due to irrigation with contaminated groundwater.     

Suitability of lysosomal membrane stability in Eisenia fetida as biomarker of soil copper contamination

Accumulated metals in soils negatively affect dwelling organisms. Earthworms, which are widespread and perform various essential functions, are able to accumulate metals that can damage the coelomic cells. The aim of this work was to evaluate the effect on Eisenia fetida lysosomal membrane stability both during and after copper exposure, and finally to link this to internal concentrations. E. fetida specimens were exposed to a reference soil and two Cu-spiked soils (35 and 350 mg kg⁻¹ d.w.) for 14 days (uptake period) and then transferred into the reference soil for other 18 days (elimination period). After 3 days of uptake, internal Cu concentrations increased and were higher in the specimens exposed to soils spiked with 350 mg Cu kg⁻¹ d.w. After 2 days of elimination, a strong decrease of internal Cu concentrations was always observed. The lysosomal membrane stability, measured as neutral red retention-times, was approximately 50 min for the earthworms exposed to the reference soils, whereas it decreased, at the end of the uptake period, to 21 and 13 min, respectively, for the organisms exposed to soils spiked with 35 and 350 mg Cu kg⁻¹ d.w. A full recovery of the lysosomal membrane stability was reached after 14 and 18 days of the elimination period, respectively, for the organisms exposed to soils spiked with 35 and 350 mg Cu kg⁻¹ d.w. The neutral-red assay would seem a good biomarker since the lysosomal membrane stability of E. fetida appeared to respond rapidly and strongly to soil copper contamination.     

Bioindication of Heavy Metals in Soil by Liverworts

Studies were made of the accumulation of the heavy metals Ba, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Sr, V, and Zn and the macroelements N, P, K, Ca, and Mg in liverworts Conocephalum conicum, Marchantia polymorphia, and Pellia epiphylla collected from 57 microhabitats in Poland (Lower Silesia, Tatry Mts., and Puszcza Augustowska forest) and one microhabitat in the Czech Republic (Moravsky Kras). Ecological differentiation of Conocephalum conicum, Marchantia polymorpha and Pellia epiphylla populations is closely correlated with the soil chemistry. The evidence for this assumption are the significant positive correlations between concentrations of elements in soil and in the examined liverworts. In particular, correlations between contents of chromium and cobalt in soil and in Conocephalum conicum and between nickel, chromium, copper, and barium in soil and in Pellia epiphylla prove that these plants can be useful in monitoring of contamination of soil with elements mentioned above. Concentrations of cobalt in almost all the examined liverworts surpass the average background values of this element established for terrestrial bryophytes what proves that these plants tolerate increased accumulated amounts of this element and may therefore act as bioindicator for this heavy metal. Cationic equilibrium of Conocephalum conicum, Marchantia polymorpha and Pellia epiphylla examined according to Czarnowski (1977) pointed to the existence of some disturbances in ionic balance of these plants caused probably by elevated concentrations of microelements (especially iron, cobalt, lead, and copper) in their tissues. Received: 30 October 1996/Revised: 2 March 1997     

Effects of heavy metals on earthworms along contamination gradients in organic rich soils

Earthworm communities and metal (bio)availability to earthworms along contamination gradients was studied in order to support chemical analyses in risk assessment of metal contaminated soils. Earthworms were sampled in three metal contaminated areas with different habitat and soil properties in Finland. Earthworm and soil samples were collected at three distances (1, 2, and 4 km) from the emission sources. Earthworms were identified as to species and analyzed for heavy metals. Total soil metal concentrations were analyzed using an ultrasound-assisted extraction method and bioavailable metal fraction was estimated by acetic acid extraction. In two of the three areas studied, heavy metal concentrations close to the emission sources were high enough to have harmful effects on earthworms and their environments. In general, diversity, total numbers, and biomass of earthworms increased with increasing distance from the emission sources. When individuals were available for analyses close to the emission source, positive correlations between metal concentrations in the earthworms and those in the soils were observed.     

Hazardous Effects of Eight Years of Application of Four Organic Waste Materials on Earthworm Numbers and Biomass in Field Lysimeters

The hazardous effects on the earthworm numbers and biomass of eight consecutive yearly applications of three levels (12.5, 25, and 50 tons of dry matter/ha/y) of four different organic sludges (municipal sewage, industrial sewage, alcohol fermentation processing, and leather processing) to earthworm-free soils were examined using field lysimeters. Results were compared with those of pig manure compost (PMC)-treated soil. Of five species (Amynthas agrestis, A. sangyeoli, A. hupeiensis, Drawida koreana, and D. japonica) from 390 adult specimens collected 4 and 8 years after treatment, the number of species appeared to be lower in sludge-treated soils than in PMC-treated soils. Earthworm populations and biomass were correlated negatively with the pollution index [∑(heavy-metal concentration in soil/tolerable level)/number of heavy metal] 4 and 8 years after treatment. These results suggest that the long-term application of these sludges, particularly from industrial sewage and leather processing, might affect adversely the establishment of Megascolecid and Moniligastrid earthworms in field conditions.     

Spatial Patterns in a Bioindicator: Heavy Metal and Selenium Concentration in Eggs of Herring Gulls (Larus argentatus) in the New York Bight

Concentrations of selenium and five heavy metals (lead, cadmium, mercury, chromium, and manganese) in the eggs of herring gulls (Larus argentatus) were studied at six breeding colonies in the New York Bight to detect locational differences and to explore their use as a bioindicator of point source or nonpoint source pollution. The herring gull is widespread in North America, Europe, and Asia, and has urban-adapted counterparts in the southern hemisphere as well. We anticipated that the chromium contamination at Jersey City and high levels of manganese in industrial releases to the Passaic River would be reflected in the nearest colony (Shooter's Island), and that lead contamination from bridge remediation would be apparent in the Jamaica Bay colonies. There were significant locational differences in all metal levels, although the patterns were not the same for all metals. Shooter's Island in Newark Bay ranked first or second for five of the elements, but inexplicably had the lowest mercury level. Cadmium levels were highest at Canarsie Pol in Jamaica Bay, but mercury levels were highest at the relatively isolated Lavallette colony in northern Barnegat Bay. Chromium and manganese levels were indeed highest at Shooter's Island, but the lead levels in Jamaica Bay were only intermediate. We predicted that the essential trace elements, manganese, chromium, and selenium, which are known to be present at relatively high concentrations in various animal species, would have relatively low coefficients of variation, reflecting homeostatic mechanisms. This was confirmed. In conclusion, herring gull egg contents can be used to monitor metal concentrations at nearby colonies to indicate areas of concern for particular metals. They may confirm suspected associations or identify hitherto unsuspected problems. Received: 22 June 1996/Accepted: 14 October 1996     

Heavy Metals and Selenium in Grebe Feathers from Agassiz National Wildlife Refuge in Northern Minnesota

Metal levels in feathers can often be used as an indicator of exposure and of potential effects in birds. In previous work at Agassiz National Wildlife Refuge, northwestern Minnesota, pied-billed grebe (Podilymbus podiceps) eggs had significantly higher levels of manganese and mercury and significantly lower levels of selenium than eared (Podiceps nigricollis) or red-necked grebes (Podiceps grisegena), but in 1999, pied-billed grebes had significantly higher levels of mercury, but lower levels of selenium and tin than the other grebes. This led us to examine whether these patterns held up in feathers of grebes as a function of age. The feathers of young birds represent local exposure. We collected feathers of flightless young and adult grebes from 1997 to 1999 in the marshes at Agassiz National Wildlife Refuge. Regression models indicated that year, age, or species were significant factors accounting for variations in the levels of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium, depending on the metal. Overall, there were significant intraspecific differences for all metals. Pied-billed grebes had the highest levels of arsenic, chromium, and selenium, and eared grebes had the highest levels of cadmium, manganese, and mercury. Pied-billed and western grebes (Aechmophorus occidentalis) had the highest levels of lead. There were significant age-related differences in cadmium, chromium, and mercury for both eared and red-necked grebes, for arsenic in eared grebes, and for lead and manganese in red-necked grebes. Adults had higher levels of all metals, except young had higher levels of chromium. Mercury in the feathers of eared grebes were higher than found from other studies with a wide range of aquatic and marine birds and were above those known to cause adverse effects in laboratory studies, suggesting some cause for concern.     

Metals in Fish along the Southeast Coast of India

Metal concentrations (cadmium, chromium, iron, lead, copper, manganese, zinc and mercury) in the muscle of five fish species (Epinephelus chlorostigma, Lutjanus russelli, Terapon jarbua, Cynoglossus arel and Lagocephalus lunaris) from the six fish landing centres along southeast coast of India were measured. In Cuddalore and Mudasalodai, the level of toxic metals cadmium, chromium and manganese were well above the permissible limits. Concentrations of cadmium, chromium, manganese and mercury in C. arel were above the permissible limit and it is consistent with their habitat and diet. The results showed a relationship between metal concentrations and pollution status of the areas.     

Non-carcinogenic Health Risk Assessment and Source Apportionment of Selected Metals in Source Freshwater Khanpur Lake,Pakistan

Selected metals (calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, sodium, lead, strontium and zinc) were measured in water samples from a source freshwater Lake. Average levels of cadmium, cobalt, chromium and lead in the waters were significantly higher than the guideline values. Health risk assessment was then carried out to determine health risk via oral route and dermal contact. Hazard quotient (via ingestion) levels of cadmium, cobalt, chromium and lead were higher than unity; suggesting potential adverse effects on local residents. Principal component analysis revealed considerable anthropogenic contributions of the metals in the water reservoir.     

Single versus multiple occupancy--effects on toxicity parameters measured on Eisenia fetida in lead nitrate-treated soil

The mortality (7 and 14 d), weight change (7 and 14 d), and metal uptake of Eisenia fetida (Savigny, 1826) kept in Pb(NO3)2-treated Kettering loam soil in single- and multiple-occupancy (10 earthworms) test containers were determined. The number of earthworms to dry mass (g) ratio of soil was 1:50 in both sets of test containers. Lead concentrations were in the nominal range of 0 to 10,000 mg Pb/kg soil (mg/kg hereafter). Levels of mortality at a given concentration were statistically identical between the single- and multiple-occupancy tests, except at 1,800 mg/kg, at which significantly (p < or = 0.05) more mortality occurred in the multiple-occupancy tests. Death of individual earthworms in the multiple-occupancy tests did not trigger death of the other earthworms in that soil. The LC50 values (concentration statistically likely to kill 50% of the population) were identical between the multiple- and single-occupancy soils: 2,662 mg/kg (2,598-2,984, 7 d) and 2,589 mg/kg (2,251-3,013, 14 d) for the multiple-occupancy soils and 2,827 mg/kg (2,443-3,168, both 7 and 14 d) for the single-occupancy soils (values in brackets represent the 95% confidence intervals). Data were insufficient to calculate the concentration statistically likely to reduce individual earthworm mass by 50% (EC50), but after 14 d, the decrease in earthworm weight in the 1,800 and 3,000 mg/kg tests was significantly greater in the multiple- than in the single-occupancy soils. At 1,000, 1,800, and 3,000 mg/kg tests, earthworm Pb tissue concentration was significantly (p < or = 0.05) greater in earthworms from the multiple-occupancy soils. The presence of earthworms increased the NH3 content of the soil; earthworm mortality increased NH3 concentrations further but not to toxic levels.     

Application of organic wastes on a benzo(a)pyrene polluted soil. Response of soil biochemical properties and role of Eisenia fetida

In this paper we studied the bioremediation effects of a soil artificially contaminated by benzo(a)pyrene with and without two organic wastes (organic municipal solid waste, MSW, and poultry manure, PM) and with and without worms (Eisenia fetida) over 90 days. For the organic treatments, soil samples were mixed with MSW at a rate of 10% or PM at a rate of 7.6%, in order to apply the same amount of organic matter to the soil. An unamended and non-polluted soil was used as control. Cellulase and glutathione-S-transferase activities in worms and the earthworms’ weight were measured at four different incubation times (3, 15, 60 and 90 days). Cocoon numbers, average weight per cocoon and number of juveniles per cocoon were measured 30 days after the benzo(a)pyrene exposure. Extractable benzo(a)pyrene in soils and E. fetida was determined during the incubation period. To observe the effects of bioremediation of the contaminated soil, ATP, urease and phosphatase activities were measured. At the end of the incubation period and when compared with the polluted soil without worms and organic matter, the extractable benzo(a)pyrene decreased by 41.2% for the unamended polluted soil and without worms, by 45.8% for the organic-PM polluted soil and without worms, 48.3% for the organic-MSW polluted soil and without worms, 55.4% for the organic-PM polluted soil and with worms, and 66.3% for the organic-MSW polluted soil and with worms. This meant that worm hydrocarbon absorption was lowest in the contaminated soil amended with MSW and with worms, causing an increase in catabolic activity of the soil. These results suggested that the co-application of organic wastes and E. fetida for the bioremediation of benzo(a)pyrene polluted soil is potentially advantageous.     

Effects of waste water sediments on the levels of heavy metals ion the soil and plants

Field small-plot experiments studied the effects of sediments of waste water from Saransk disposal systems. The content of toxic heavy metals (lead, arsenic, and cadmium) in the waste-water sediments, was shown to be not greater than their maximum permissible concentrations (32, 2, and 10 mg per kg of dried soil, respectively). With the use of waste-water sediments, the content of manganese, copper, tin, nickel, vanadium, beryllium, cobalt, iron, and chromium was found to correspond to their baseline level in the soil and plants.