Highest Bioconcentration Factor Values Research Articles

Antimicrobials in Eisenia fetida earthworms: A comprehensive study from method development to the assessment of uptake and degradation

In this work, an accurate analytical method was developed for the simultaneous analysis of twenty-seven antimicrobials (AMs) in earthworms using liquid chromatography coupled to a triple quadrupole mass spectrometry detector (UHPLC-MS/MS). Adequate apparent recoveries (80–120 %) and limits of quantification (LOQ) (1 μg·kg−1 - 10 μg·kg−1) were obtained, with the exception of norfloxacin (34 μg·kg−1). The method was applied to evaluate the accumulation of sulfamethazine (SMZ) and tetracycline (TC) in earthworms after performing OECD-207 toxicity test, in which Eisenia fetida (E. fetida) organisms were exposed to soils spiked with 10 mg·kg−1, 100 mg·kg−1 or 1000 mg·kg−1 of SMZ and TC, individually. The results confirmed the bioaccumulation of both AMs in the organisms, showing a greater tendency to accumulate SMZ since higher bioconcentration factor values were obtained for this compound at the exposure concentrations tested. In addition, the degradation of both AMs in both matrices, soils and earthworms was studied using liquid chromatography coupled to a q-Orbitrap high resolution mass spectrometry detector. Thirteen transformation products (TPs) were successfully identified, eight of them being identified for the first time in soil/earthworm (such as 4-Amino-3-chloro-n-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide or 4-(dimethylamino)-1,11,12a-trihydroxy-6,6-dimethyl-3,7,10,12-tetraoxo-3,4,4a,5,5a,6,7,10,12,12a-decahydrotetracene-2-carboxamide, among others) and their formation/degradation trend over time was also studied. Regarding the biological effects, only SMZ caused changes in earthworm growth, evidenced by weight loss in earthworms exposed to concentrations of 100 mg·kg−1 and 1000 mg·kg−1. Riboflavin decreased at all concentrations of SMZ, as well as at the highest concentration of TC. This indicates that these antibiotics can potentially alter the immune system of E. fetida. This research represents a significant advance in improving our knowledge about the contamination of soil by AM over time. It investigates the various ways in which earthworms are exposed to AMs, either by skin contact or ingestion. Furthermore, it explores how these substances accumulate in earthworms, the processes by which earthworms break them down or metabolise them, as well as the resulting TPs. Finally, it examines the potential effects of these substances on the environment.

Plankton diversity and its heavy metal content in Ratai Bay of Pesawaran district, Lampung, Indonesia.

Artisanal and small-scale gold mining (ASGM) activity in Way Ratai River produces heavy metal wastes; therefore, further information regarding heavy metal concentrations in the water was needed, especially in plankton samples. Furthermore, the determination of plankton diversity was also carried out in the waters of Way Ratai to determine the bioconcentration factor (BCF). Eight sampling sites were chosen along the river reaching the coast of Way Ratai. The research was conducted in November 2020 and March 2021. Ten heavy metals, Ag, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn that are commonly found in mining areas, were determined in the water and plankton samples by using ICP-OES. The results indicated that the highest concentration found was Fe in plankton samples (0.725 mg/L in the river and 1.294 mg/L on the coast). Meanwhile, contents of Cd, Cu, Fe, Mn, and Zn in the river exceeded the predetermined water quality standards, while Ag and Pb metals were not detected. The Cd, Cr, Cu, Pb, and Zn content in seawater also exceeded quality standards. The highest BCF value (12.96) was found for Fe at station G, whereas the lowest BCF value (0.13) was found for Ag at stations G and H.

Artificial intelligence-based approaches to evaluate and optimize phytoremediation potential of in vitro regenerated aquatic macrophyte Ceratophyllum demersum L.

Water bodies or aquatic ecosystem are susceptible to heavy metal accumulation and can adversely affect the environment and human health especially in underdeveloped nations. Phytoremediation techniques of water bodies using aquatic plants or macrophytes are well established and are recognized as eco-friendly world over. Phytoremediation of heavy metals and other pollutants in aquatic environments can be achieved by using Ceratophyllum demersum L. - a well-known floating macrophyte. In vitro regenerated plants of C. demersum (7.5g/L) were exposed to 24, 72, and 120h to 0, 0.5, 1.0, 2.0, and 4.0mg/L of cadmium (CdSO4·8H2O) in water. Results revealed significantly different relationship in terms of Cd in water, Cd uptake by plants, bioconcentration factor (BCF), and Cd removal (%) from water. The study showed that Cd uptake by plants and BCF values increased significantly with exposure time. The highest BCF value (3776.50) was recorded for plant samples exposed to 2mg/L Cd for 72h. Application of all Cd concentrations and various exposure duration yielded Cd removal (%) between the ranges of 93.8 and 98.7%. These results were predicted through artificial intelligence-based models, namely, random forest (RF), extreme gradient boosting (XGBoost), and multilayer perceptron (MLP). The tested models predicted the results accurately, and the attained results were further validated via three different performance metrics. The optimal regression coefficient (R2) for the models was recorded as 0.7970 (Cd water, mg/L), 0.9661 (Cd plants, mg/kg), 0.9797 bioconcentration factor (BCF), and 0.9996 (Cd removal, %), respectively. These achieved results suggest that in vitro regenerated C. demersum can be efficaciously used for phytoremediation of Cd-contaminated aquatic environments. Likewise, the proposed modeling of phytoremediation studies can further be employed more comprehensively in future studies aimed at data prediction and optimization.

Phytoremediation Potential of Native Hyperaccumulator Plants Growing on Heavy Metal-Contaminated Soil of Khatunabad Copper Smelter and Refinery, Iran

The characterization of prospective plants is one of the critical issues in the efficiency and success of the phytoremediation process. Due to adaption and tolerance to different environmental stresses, native plant species have priority in this method. This study examined fifty plants of five species, namely Launaea acanthodes, Artemisia sp., Cousinia congesta, Peganum harmala, and Stipa sp., growing near a smelter and refinery in Iran to identify potential species for phytoextraction and phytostabilization. Therefore, Pb, Ni, Mn, Mo, S, and Cu concentrations in sampled plants and soils were analyzed. Three different pollution indices, namely metal accumulation index (MAI), translocation factor (TF), and bioconcentration factor (BCF) were used for evaluating the metal concentrations in roots and shoots of each plant species. The results indicated that Artemisia sp., with values of 3.21, 1.09, and 1.14 for MAI, BCF, and TF, respectively, is appropriate for phytoextraction in the study area. Plants such as Launaea acanthodes and Cousinia congesta with high BCF and low TF values showed the potential for phytostabilization. Investigating the indices for different elements demonstrated that Launaea acanthodes had a BCF value greater than 1 and a TF value less than 1; therefore, this plant could be used in the phytoremediation of arsenic through the phytostabilization technique. Furthermore, copper has very low bioavailability in these plant species. In addition, these native plant species were highly capable of accumulating sulfur from the soil because the BCF and TF indices for all inspected species were higher than 1; for Launaea acanthodes, the relevant TF value was about 10. The proposed native plant could be applied in practical applications of phytoremediation for soil remediation of contaminated sites around the metal factories and mines in southeastern Iran.

Levels of metals and elements in tissues of fish species in the Kızılırmak River (Turkey) and assessment of health risks and nutritional benefits

Although the Kızılırmak River, the longest river in Turkey, is home to many fish species, there are a few studies reporting metal levels in fish in the river. The contents of 17 metals and elements (MEs) in various tissues of three fish species and surface water from the river were investigated. Significant differences in the ME levels among tissues were recorded, and the highest levels of most MEs were recorded in the gills and liver. The results revealed that correlations between MEs in tissues and fish size were not clear and consistent. Among the MEs, P (6058–109489) and Zn (933–47556) had the highest bioconcentration factor values. The levels of As and Cd in the river water exceeded water quality criteria. Health risk assessment methods (Target Hazard Quotient, Estimated Daily Intake and Lifetime Carcinogenic Risk) indicated that consumption of the studied fish species is safe. It was estimated that a weekly consumption of 490 g of C. gibelio, or 350 g of C. carpio or 280 g of T. tinca would not cause any health risks. Furthermore, it was found that fish species would provide significant benefits in terms of intake of nutrients such as P, K, Ca, Mg, Cu, Zn, Fe and Mn. These findings revealed that nutritional benefits from consumption of fish species outweigh the health risks posed by metals in fish.

Investigation of plant contamination to Ni, Pb, Zn, and Cd and its relationship with spectral reflections.

This study aims to investigate the toxicity of the plant to heavy elements (HMs). For this purpose, the estimated daily intake (EDI) parameters of potentially toxic elements (PTE) per kilogram of body weight, target hazard quotient (THQ) for non-carcinogenic disorders, total hazard index (HI), and bioconcentration factor (BCF) are determined in the plant at different stages of growth. In this study, the reaction of the plant to different electromagnetic waves at different stages of growth (DSG) is also investigated, and the relationship between the THQ values and electromagnetic waves is prepared. The results show that Pb has the highest EDI value (5.97), Pb (74.67) and Cd (9.75) have the highest THQ values, and Cd has the highest BCF value (30.44). Also, the results show that HI values are higher than the threshold in the growth (69.98), flowering (71.38), and fruiting (68.06) stages. Results of BCF indicate Pb, and Cd has absorption rate in Capsicum towards. Contaminated Capsicum plants submitted to electromagnetic waves showed a significant relationship between Pb and the b490, and b560 spectra, Cd and Ni the b450 spectrum, and Zn the b460 spectrum. This finding highlights the salience of employing electromagnetic waves in assessing contamination in plants. Put differently, THQ can be estimated using electromagnetic waves without any need for laboratory studies.

Uranium Rhizofiltration by Lactuca sativa, Brassica campestris L., Raphanus sativus L., Oenanthe javanica under Different Hydroponic Conditions

Rhizofiltration experiments were conducted using uranium-contaminated groundwater and lettuce (Lactuca sativa), Chinese cabbage (Brassica campestris L.), radish (Raphanus sativus L.), and buttercup (Oenanthe javanica), which are commonly grown and consumed in South Korea. The results of the rhizofiltration experiments with artificial solutions with different initial uranium concentrations (18, 32, 84, 116, 173, and 263 μg/L) show that the uranium accumulation and bioconcentration factor (BCF) of plant roots increase with increasing uranium concentration in the groundwater. Among the four plants, the uranium concentration in the roots of Raphanus sativus L. is 1215.8 μg/g dry weight, with a maximum BCF value of 2692.7. The BCF value of the artificial solutions with various pH values (pH 3, 5, 7, and 9) is the highest under acidic conditions (pH 3) for all four plants. The uranium BCF values based on different hydroponic conditions range from 170.5 to 11580.3 and the results are comparable with those of other studies using similar methods; the highest BCF value was determined for Brassica campestris L. at pH 3. The BCF values of Raphanus sativus L. after the rhizofiltration experiments with genuine groundwater contaminated with uranium are the highest among the four species; that is, 1684.7 and 1700.1 in Oesam-dong and Bugokdong groundwater samples with uranium concentrations of 83 and 173 μg/L, respectively. The results of the scanning electron microscope/electron dispersive X-ray spectroscope analyses show that uranium in contaminated groundwater is adsorbed as a solid phase on the root surface. These results demonstrate that Raphanus sativus L. has a high tolerance to high concentrations of uranium and low pH conditions and a remarkable potential for uranium accumulation.

Assessment of Trace Metal Contents of Indigenous and Improved Pastures and Their Implications for Livestock in Terms of Seasonal Variations

The research was aimed to determine seasonal effects on trace metals levels in soil, forages and blood plasma of animals. The mean cadmium, chromium and copper values in soil samples in different sampling seasons were ranged from 6.97 to 4.10, 0.060 to 0.72 and 3.54to 4.08 mg/kg, respectively, while, in forage samples were between 0.671-0.697, 1.57-2.22 and 6.75-7.06 mg/kg, respectively. Higher Cd, Cr and Cu concentrations were observed in blood plasma of young buffaloes during summer season, in dry buffaloes during spring season and in young buffaloes during autumn season, while lower Cd, Cr and Cu contents were noticed in blood plasma of lactating buffaloes in summer season. The highest bio-concentration factor value from soil to forage was determined for Cr while from forage to blood plasma of buffaloes was detected for Cd. The Cd, Cr and Cu correlation of soil with blood plasma were positive for all samples.

Phytoremediation potential of some grasses on lead heavy metal in tailing planting media of former tin mining

Abstract. Khodijah NS, Suwignyo RA, Harun MU, Robiartini L. 2019. Phytoremediation potential of some grasses on lead heavy metal in tailing planting media of former tin mining. Biodiversitas 20: 1973-1982. Agricultural production on tin tailings land must consider the safety of products from Pb metal contaminants. The presence of Pb metal can be overcome by using plants as phytoremediation. This study aimed to obtain information on the ability of phytoremediation of Pb by various types of grass and its interaction with the types of ameliorants in tin tailings media. Three species of grass were used, namely Pennisetum purpureum, Saccharum spontaneum, and Hymenachne acutigluma, and two types of ameliorant, namely lime and compost. The study was designed using a factorial treatment design laid out in a completely randomized design with two treatment factors, namely the type of grass and the type of ameliorant. Observations were done on growth, shoot Pb content and root Pb content. The ability of phytoremediation was assessed by using the approach of Bioconcentration factor (BCF) and Translocation Factor (TF) values. The highest phytoremediation ability was found in treatment of H. acutigluma grass treated with lime ameliorant, followed by S. spontaneum treated with lime ameliorous and S. spontaneum treated with compost ameliorant. Based on BCF values, P. purpureum and H. acutigluma were categorized as accumulators, and S. spontaneum was classified as an excluder. Based on TF values, the three types of grass used were classified as phytostabilisation. The high ability of phytoremediation in H. acutigluma was caused by its high BCF values, ​​while the high ability of phytoremediation on S. spontaneum was caused by its low translocation factor value and high Pb absorption efficiency.

Arsenic forms in phytoextraction of this metalloid in organs of 2-year-old Acer platanoides seedlings

The aim of the study was to estimate the significance of the role of arsenite (As(III)), arsenate (As(V)), and dimethylarsinic acid (DMA) presence in modified Knop medium in the efficiency of phytoextraction of arsenic (As) in Acer platanoides root, stem, and leaves. The addition of particular As forms in single, double, and triple experimental systems was associated with a lower increase of seedling biomass compared to control plants (system free of As forms addition). Depending on As forms and their concentration in solution, negative symptoms from slight visible changes (inorganic forms separately or jointly), through smaller and discolored leaves (after DMA addition), and finally to their withering (after high DMA addition) were observed. Changes of color and shape for root systems exposed to particular As forms separately or jointly were also observed, in spite of the fact that there were no significant changes in biomass of seedlings growing in all experimental systems. The highest mean concentrations of As in root, stem, and leaves (590, 70, and 140 mg kg−1 dry weight (DW), respectively) were observed in plants growing under different experimental systems. The highest bioconcentration factor values were 10.8 for plants exposed to 0.06 mM of As(III) and DMA, while the highest translocation factor (1.0) was recorded for plants growing under the same As forms (0.6 and 0.06 mM, respectively). The obtained results indicate that the presence of particular As forms not only determines As phytoextraction and transport of this metalloid form but also has a decisive influence on plant morphology and survivability. As regards the practical aspects of phytoremediation, the kind of As forms present in substrate are more important than their total concentration.

Phytoextraction with Salix viminalis in a moderately to strongly contaminated area.

We tested the suitability of Salix viminalis for phytoextraction with the analysis of selected elements in soil, root, and leaf, and by visual tree condition assessment in an area with varying levels of contamination. Bioconcentration factor (BCF) and translocation factor (TF) were used to assess the phytoextraction potential of willows. The middle part of the study area was strongly contaminated, while the northern and southern parts were moderately contaminated. We found increasing element concentrations toward deeper layers. Mean concentrations of elements in roots were similar among the three parts, while in leaves the highest concentrations were found in the strongly contaminated part of the study area. Tree condition scores were the lowest in the strongly contaminated part of the study area, which was caused by Al, Ca, K, Mg, Ni, Sr, and Zn concentration. These elements induced leaf disease and leaf feeders. The highest BCF values were found for Cu, Fe, Mn, and Zn in root, and for Cd and Zn in leaves, indicating that S. viminalis had high accumulation potential of these elements. Furthermore, TF values were high for Cd, Mn, Sr, and Zn. Our results also demonstrated that soil element composition has major influence on the condition of S. viminalis individuals. Furthermore, visual condition assessment was found to be a useful tool to assess the phytoextraction potential of trees.

Cadmium in edible plants from Silesia, Poland, and its implications for health risk in populations

The health risk associated with cadmium exposure through consumption of edible plants cultivated in different parts of the Silesia administration area inhabitants has been estimated. The impact of the arable soils acidity on the BCF (bioconcentration factor) has been also analyzed. The concentration of cadmium in arable soils and in 118 samples of vegetables - carrots, beets, potato, celery (tuber), parsley (root) were determined. The cadmium content in examined soil samples were in the range from >0.5–68.5mgkg−1 d.w. The most contaminated samples, above the maximum permissible concentration, originated from the central part of the region. The highest BCF value in case of parsley roots and carrots has been shown (0.941 and 0.828 respectively). Significant correlation between soil pH and BCF in examined edible plants has been demonstrated. In the exposure scenario, which assumes the consumption of the most contaminated vegetables from Silesia administration area, the value of the hazard quotient (HQ) for Cd was 2.56. On the contaminated arable soils from the central part of Silesia administration area the non-edible plants should be cultivated. In case of acidic and slightly acidic pH-range of arable soils, some methods of metals immobilization in soil are recommended e.g. liming.

Assessment of toxicological health risk of trace metals in vegetables mostly consumed in Punjab, Pakistan

In the present study, levels of trace metals in two commonly consumed vegetables (Spinacia oleracea and Brassica campestris) were assessed. Both vegetables are cultivated in a semi-arid area which receives effluents from various sources. Leafy parts and tender stems are used for human consumption as well as for farm animals as a source of nourishment. However, the aim of the present study was to appraise the concentrations of trace metals in different tissues of both vegetables at the time of harvesting when they become accessible to the humans. The analysis showed that mean trace metal levels in the stem of S. oleracea showed the highest bioconcentration of Zn (25.43 mg kg−1), while in the stem (28.56 mg kg−1) and roots (22.40 mg kg−1), Fe level was the highest. In case of B. campestris, Fe level was highest (18.45 mg kg−1) in the stems. Copper (Cu) has the highest bioconcentration factor values (BF = 1.030) in the stem of B. campestris, whereas Mn (BF = 0.010) was the least accumulated element in the leaves and roots of B. campestris. Collectively, bioconcentration of trace metals in plant tissues exceeded the standard values set by the World Health Organization (WHO) and the US Environmental Protection Agency. So, the vegetables cultivated in effluent-impacted areas may stance a potential public health risk for end-consumers.

Bioaccumulation of metals in timber and edible fruit trees growing on reclaimed coal mine overburden dumps

A field study was carried out (IB-valley areas, Mahanadi Coalfields Limited) to assess the bioaccumulation of heavy metals in the tree species, changes in physicochemical and nutritional properties of mine soils, and bioavailability of metals. Only limited amount of topsoil was added in the plantation pits in the ratio of 1:4 (topsoil: weathered mine spoils), which significantly improved pH and fertility. Out of the six analysed metals, the highest concentration was found for Fe followed by Mn > Zn > Cu > Cd > Ni in mine soils. Metal accumulation and bioconcentration factor (BCF) for each metal were calculated for edible fruit (Mangifera indica, Anacardium occidentale, Psidium guajava, Artocarpus heterophyllus and Syzygium cumini) and timber trees (Acacia mangium, Eucalyptus spp., Techtona grandis and Gravellia robusta). Higher metal accumulations were observed in edible fruit trees than control plants growing in garden soil. Significant variations of metal accumulations were observed amongst timber tree species with higher BCF values. Present study suggested that in spite of addition of topsoil, no significant improvement was observed for the bioavailable metal concentration in the mine soils. Additional care should be undertaken, if edible fruit trees are considered for afforestation of coal mine spoils.

Phytoremediation potential of charophytes: Bioaccumulation and toxicity studies of cadmium, lead and zinc

The ability for usage of common freshwater charophytes, Chara aculeolata and Nitella opaca in removal of cadmium (Cd), lead (Pb) and zinc (Zn) from wastewater was examined. C. aculeolata and N. opaca were exposed to various concentrations of Cd (0.25 and 0.5 mg/L), Pb (5 and 10 mg/L) and Zn (5 and 10 mg/L) solutions under hydroponic conditions for 6 days. C. aculeolata was more tolerant of Cd and Pb than N. opaca. The relative growth rate of N. opaca was drastically reduced at high concentrations of Cd and Pb although both were tolerant of Zn. Both macroalgae showed a reduction in chloroplast, chlorophyll and carotenoid content after Cd and Pb exposure, while Zn exposure had little effects. The bioaccumulation of both Cd and Pb was higher in N. opaca (1544.3 μg/g at 0.5 mg/L Cd, 21657.0 μg/g at 10 mg/L Pb) whereas higher Zn accumulation was observed in C. aculeolata (6703.5 μg/g at 10 mg/L Zn). In addition, high bioconcentration factor values (> 1000) for Cd and Pb were observed in both species. C. aculeolata showed higher percentage of Cd and Pb removal (> 95%) than N. opaca and seemed to be a better choice for Cd and Pb removal from wastewater due to its tolerance to these metals.

Phytosequestration of Metals in Selected Plants Growing on a Contaminated Okhla Industrial Areas, Okhla, New Delhi, India

Contamination of metal ions in soil and water represents more pressing threats to resources as well as human health. The present research was carried out to screen the phytosequester plants growing in industrial waste- and wastewater-affected industrial areas of Okhla, New Delhi, India. Accumulation trend of metal Fe, Zn, Cu, Cr, Pb, Cd, Hg, and As from soil and wastewater by plants were collected for study. Among aquatic plants Hydrilla verticillata, Marsilea quadrifolia, and Ipomea aquatica were found to be highest metals accumulator, Eclipta alba and Sesbania cannabina among terrestrial plant were highest accumulator of metals. Among the algal spp. Spirulina platensis and Phormidium papyraceum were the most efficient in accumulating Cd and Hg. The maximum bioconcentration factor (BCF) was recorded in Hygroryza aristata for the metals (Hg, Cd) in M. quadrifolia (Cd, Cr), in E. alba (Cr, Cu), and in S. platensis (Hg, Pb). However, the translocation factor (TF) of metals was found more in M. quadrifolia followed by I. aquatica than other plants. Among all the plants, H. verticillata showed high TF and low BCF values for toxic metals (Pb, Cr) and was suitable for phytostabilization of these metals. Our study showed that native plant species growing on contaminated sites may have a potential of phytosequestration of these metals.

Decontamination and/or revegetation of fly ash dykes through naturally growing plants

Present study is focused on the decontamination and/or revegetation of fly ash dykes through naturally growing plants, namely Calotropis procera, Cassia tora, Chenopodium album, Sida cardifolia, Blumea lacera. The results of sequential extraction study showed that maximum amount of metals (Na, K, Fe, Mn, Cr, Pb, Ni, Cd) were associated with residual and Fe–Mn fractions. Diethylenetriamine penta acetic acid (DTPA)–triethanolamine (TEA) extraction assessed the bioavailability of the metals. The total metal accumulation in tested plants was found in the order; C. album > S. cardifolia > C. tora > C. procera > B. lacera. The maximum bioconcentration factor (BCF) was recorded in S. cardifolia for the metals (Na, Fe, Zn, Cd), in C. procera for the metals (Mn, Cu, Ni, Cr) and in C. album for the metals (Co, Pb). However, the translocation factor (TF) of most of the metals was found more in S. cardifolia followed by C. album than other plants . Among all the plants, C. album have shown high BCF and low TF values for toxic metals (Pb, Cd) and suitable for phytostabilization of these metals. Principal component analysis was used to predict translocation behavior of the metals in different parts of the plants which was found similar for the metals (Cu, Zn, Mn, Cr). All examined plants are suitable for revegetation (naturally grows on fly ash dykes) and S. cardifolia and C. album may be used for decontamination purposes.

Comparative study on bioaccumulation of lead and cadmium by the cyanobacterium Synechocystis sp. PCC 6803 under laboratory conditions

Bioremoval techniques have been employed in cleaning water bodies that suffer from detrimental effects of heavy metal pollution. In the present laboratory study, bioaccumulation of Pb2+ and Cd2+ was assessed using the unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism widely used in genetic, physiological and morphological studies. Growth was measured as cell counts and showed that Pb2+, at low exposure concentrations (0.5 and 1 µg mL–1), had a positive influence on Synechocystis sp. PCC 6803, resulting in slight growth stimulations; however, the species could not withstand long periods of exposure to both metals at higher concentrations (2, 4, 6 and 8 µg mL–1). The highest inhibitions (53.14% and 70.07% for Pb2+ and Cd2+, respectively, at 8 µg mL–1) were recorded after six days. Rapid metal removal was observed during the first two days of incubation, followed by a gradual reduction. Though the differences in accumulated amounts seemed to be narrow, the percentage of Pb2+ removed from the solution was always higher than that of Cd2+ in all the treatments. Accumulated amounts increased in a dose-dependent manner for both metals. The maximum accumulations (155.63 and 199.83 mg g–1 dry weight for Pb2+ and Cd2+, respectively) were recorded at the end of six days. The species can be considered a good accumulator of metals, with high bioconcentration factor values of 20 657 and 24 980 for Pb2+ and Cd2+, respectively.

Arsenic Bioaccumulation in Freshwater Fishes

ABSTRACT The arsenic ambient water quality criterion (AWQC) for protection of human health via ingestion of aquatic organisms is currently 0.14 μ g/L. This AWQC is derived using a bioconcentration factor (BCF) of 44, which is a consumption-weighted average based on two data points for oysters and fish that was proposed by the U.S. Environmental Protection Agency in 1980 for broad application to freshwater and marine environments. This BCF is based on the assumption that bioaccumulation is a simple linear function of the exposure concentration. In the nearly quarter of a century since this BCF was promulgated, there have been additions to the arsenic bioaccumulation database and a broader scientific understanding of bioaccumulation mechanisms and how they can be applied to estimating tissue concentrations in aquatic organisms. From this database, we identified 12 studies of arsenic bioaccumulation in freshwater fishes in order to explore differences in laboratory-generated BCFs and field-generated bioaccumulation factors (BAFs) and to assess their relationship to arsenic concentrations in water. Our analysis indicates that arsenic concentrations in tissue and arsenic BAFs may be power functions of arsenic concentration in water. A power function indicates that the highest BCF values may occur at low background levels and may decrease as environmental concentrations increase above the ambient range.