Assessing metal bioaccumulation in aquatic environments: The inverse relationship between accumulations factors, trophic transfer factors and exposure concentration

Rio Tinto Minerals, Greenwood Village, Colorado, United States
Aquatic Toxicology (Impact Factor: 3.51). 08/2007; 84(2):236-46. DOI: 10.1016/j.aquatox.2007.02.022
Source: PubMed

ABSTRACT Bioaccumulation potential in aquatic biota is typically expressed using ratios of chemical concentrations in organism tissue (typically whole body) relative to chemical exposure concentrations, such as bioconcentration factors (BCFs). Past reviews of metal BCFs for aquatic biota, which account for water-only exposures, have shown that BCFs are often highly variable between organisms and generally inversely related to exposure concentration. This paper further evaluates trends in metal bioaccumulation data by evaluating data for bioaccumulation factors (BAFs) and trophic transfer factors (TTFs). Bioaccumulation factor data were compiled from field studies that account for combined waterborne and dietary metal exposures. Trophic transfer factor data for metals were compiled from laboratory studies in which aquatic food chains were simulated. Natural aquatic food webs are rarely sufficiently understood to properly evaluate exact predator-prey relationships (i.e., TTFs). Results indicate that field BAFs, like laboratory BCFs, tend to be significantly (p < or = 0.05) inversely related to exposure concentration. Bioaccumulation factors are frequently 100-1000 times larger than BCFs for the same metal and species. This difference is attributed to both lower exposure levels in the field and inclusion of the dietary exposure route. Trophic transfer factors for the metals reviewed, including selenium and methyl mercury were also observed to be inversely related to exposure concentration, particularly at lower exposure concentrations. These inverse relationships have important implications for environmental regulations (e.g., hazard classification and tissue residue-based water quality criteria) and for the use of metal bioaccumulation data in site-specific environmental evaluations, such as ecological and human health risk assessments. Data presented indicate that for metals and metalloids, unlike organic substances, no one BAF or TTF can be used to express bioaccumulation and/or trophic transfer without consideration of the exposure concentration.

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    • "However, the metabolites were not determined in the present study, thus, ignoring possible metabolism might run the risk of underestimating the actual bioaccumulation of pharmaceuticals. Previous studies on metal bioaccumulation in an aquatic environment indicated that BAFs, similar to laboratory BCFs, tend to be significantly inversely related to the exposure concentration (DeForest et al., 2007); however, this relationship was also found in previous studies on pharmaceuticals (i.e., ROX, ERY and DIC) (Liu et al., 2014a, 2014c; Schwaiger et al., 2004). In this study, the BAFs of frequently detected LPhACs (ROX, ERY, CBZ and DIC) in the liver and brain tissues were compiled for the two wild fish species (Fig. 2). "
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    ABSTRACT: The occurrence, bioaccumulation and risk assessment of lipophilic pharmaceutically active compounds (LPhACs), such as antibiotics (roxithromycin, erythromycin and ketoconazole), anti-inflammatories (ibuprofen and diclofenac), β-blockers (propranolol), antiepileptics (carbamazepine) and steroid hormones (17α-ethinylestradiol), were investigated in the downstream rivers of sewage treatment plants in Nanjing, China. The results indicate that these LPhACs were widely detected in the surface water and fish samples, with the mean concentrations of the total LPhACs (ΣLPhACs) being in the range of 15.4 and 384.5 ng/L and 3.0 and 128.4 ng/g (wet weight), respectively. The bioaccumulation of the ΣLPhACs in wild fish tissues was generally in the order the liver > brain > gill > muscle. Among the target LPhACs, however, an interspecies difference in tissue distribution was evident for erythromycin. The bioaccumulation factors of LPhACs in the liver and brain, the two major targeted storage sites for toxicants, exhibited an obvious negative correlation with the aquatic concentrations (P < 0.05). Finally, risk quotients posed by pharmaceuticals were assessed by comprehensive and comparative methods for different aquatic organisms (algae, daphnids and fish). The overall relative order of susceptibility was estimated to be algae > daphnids > fish. However, the results indicate that diclofenac, ibuprofen and 17α-ethinylestradiol each posed chronic risks for high trophic level organisms (fish). In all of the risk assessments, erythromycin was found to be the most harmful for the most sensitive algae group. In this work, however, the total BAF and toxicological interactions of pharmaceuticals were not performed due to the lack of metabolite information and combined toxicity data, which represents a major hindrance to the effective risk assessment of pharmaceuticals.
    Science of The Total Environment 04/2015; 511. DOI:10.1016/j.scitotenv.2014.12.033 · 4.10 Impact Factor
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    • "Bioaccumulation factors could be calculated for As, Cd, Cu, Pb, Se, and Zn based on spatially and temporally colocated concentrations measured in brine shrimp and filtered surface water samples. Consistent with other studies (McGeer et al. 2003; DeForest et al. 2007), BAFs for these trace elements tended to be inversely related to dissolved concentrations in surface water (Fig. 9). The slope of the relationship between the log element concentration in brine shrimp versus the log element concentration in filtered surface water was statistically significant (p<0.001) for all elements except P b (p = 0. 26 ) . "
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    ABSTRACT: This paper presents long-term monitoring data for 19 elements with a focus on arsenic (As), copper (Cu), and selenium (Se), in surface water (2002-2011), brine shrimp (2001-2011), and brine flies (1995-1996) collected from Great Salt Lake (GSL, Utah, USA). In open surface waters, mean (±standard deviation [SD]; range; n) As concentrations were 112 (±22.1; 54.0-169; 47) and 112 μg/L (±35.6; 5.1-175; 68) in filtered and unfiltered surface water samples, respectively, and 16.3 μg/g (±5.6; 5.1-35.2; 62) dry weight (dw) in brine shrimp. Mean (±SD; range; n) Cu concentrations were 4.2 (±2.1; 1.3-12.5; 47) and 6.9 μg/L (±6.6; 1.9-38.1; 68) in filtered and unfiltered surface water samples, respectively, and 20.6 μg/g (±18.4; 5.4-126; 62) dw in brine shrimp. Finally, mean (±SD; range; n) dissolved and total recoverable Se concentrations were 0.6 (±0.1; 0.4-1.2; 61) and 0.9 μg/L (±0.7; 0.5-3.6; 89), respectively, and 3.6 μg/g (±2.2; 1.1-14.9; 98) dw in brine shrimp. Thus, Se in open lake surface waters was most often in the range of 0.5-1 μg/L, and concentrations in both surface water and brine shrimp were comparable to concentrations measured in other monitoring programs for the GSL. Temporally, the statistical significance of differences in mean dissolved or total recoverable As, Cu, and Se concentrations between years was highly variable depending which test statistic was used, and there was no clear evidence of increasing or decreasing trends. In brine shrimp, significant differences in annual mean concentrations of As, Cu, and Se were observed using both parametric and nonparametric statistical approaches, but, as for water, there did not appear to be a consistent increase or decrease in concentrations of these elements over time.
    Environmental Monitoring and Assessment 03/2015; 187(3):4231. DOI:10.1007/s10661-014-4231-6 · 1.68 Impact Factor
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    • "Notably, earthworm accumulated a certain amount of toxic metals of in their tissues, and inevitably introduced metals into terrestrial food chains. However, the general consensus is that while earthworms can render metals available to their predators, the concentrations of metals do not bio-magnify during transference to higher-trophic levels (DeForest et al., 2007; Roodbergen et al., 2008). Nevertheless, we cannot exclude the possibility that the accumulation of metals by earthworms has no potentially serious ecotoxicological impacts. "
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