1
|
Frankel TE, Crowell C, Giancarlo L, Hydorn D, Odhiambo BK. Investigating the potential impacts of coal ash runoff on the freshwater Seminole ramshorn snail (Planorbella duryi) under laboratory conditions. CHEMOSPHERE 2023; 310:136815. [PMID: 36241101 DOI: 10.1016/j.chemosphere.2022.136815] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Coal fly ash is an industrial waste product generated by coal fired powerplants which has been shown to contain elevated concentrations of several toxic trace metals. When stored in landfills or other repositories, these trace metals can enter nearby surface waters via a number of routes including leaching or runoff. Our study examined 1) the presence and concentration of eleven trace elements in a range of lab-created coal ash leachate solutions at neutral pH using ICP-OES, 2) the physiological effects of these leachate solutions on a freshwater gastropod (Planorbella duryi), and 3) the ability of these trace metals to bioaccumulate in the tissues of exposed individuals. As, Cd, Cu, Mg, Mn, and Pb were detected in solutions at increasing concentrations concurrent with ash concentration. Exposure to leachates caused significant delays in embryonic development, reduced juvenile shell growth, decreases in egg and clutch production, and the display of avoidance behaviors. Tissues of exposed snails contained elevated concentrations of As, Cd, Cu, and Cr, with bioconcentration factors 177,550 times higher in cadmium and 85,468 times higher in arsenic in the highest treatment compared to control organisms. Our results highlight the potential harmful effects of coal ash leachates on a novel freshwater invertebrate species using several unique methodologies, providing key information regarding their potential impacts on surrounding aquatic ecosystems.
Collapse
Affiliation(s)
- T E Frankel
- Department of Earth and Environmental Sciences, University of Mary Washington, Fredericksburg, VA, USA, 22401.
| | - C Crowell
- Department of Earth and Environmental Sciences, University of Mary Washington, Fredericksburg, VA, USA, 22401
| | - L Giancarlo
- Department of Chemistry and Physics, University of Mary Washington, Fredericksburg, VA, USA, 22401
| | - D Hydorn
- Department of Mathematics, University of Mary Washington, Fredericksburg, VA, USA, 22401
| | - B K Odhiambo
- Department of Earth and Environmental Sciences, University of Mary Washington, Fredericksburg, VA, USA, 22401
| |
Collapse
|
2
|
Tallarico LDF, Borrely SI, Hamada N, Grazeffe VS, Ohlweiler FP, Okazaki K, Granatelli AT, Pereira IW, Pereira CADB, Nakano E. Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2014; 110:208-215. [PMID: 25259848 DOI: 10.1016/j.ecoenv.2014.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/28/2014] [Accepted: 09/03/2014] [Indexed: 06/03/2023]
Abstract
A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies.
Collapse
Affiliation(s)
- Lenita de Freitas Tallarico
- Laboratório de Parasitologia/Malacologia, Instituto Butantan, Avenida Vital Brasil, 1500, CEP 05503-900, São Paulo, SP, Brazil; Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, no 2242, Cidade Universitária, CEP 05508-000, São Paulo, SP, Brazil.
| | - Sueli Ivone Borrely
- Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, no 2242, Cidade Universitária, CEP 05508-000, São Paulo, SP, Brazil
| | - Natália Hamada
- Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, no 2242, Cidade Universitária, CEP 05508-000, São Paulo, SP, Brazil
| | - Vanessa Siqueira Grazeffe
- Laboratório de Parasitologia/Malacologia, Instituto Butantan, Avenida Vital Brasil, 1500, CEP 05503-900, São Paulo, SP, Brazil
| | - Fernanda Pires Ohlweiler
- Laboratório de Malacologia, Superintendência de Controle de Endemias, Rua Cardeal Arcoverde, no 2878, CEP 05408-003, São Paulo, SP, Brazil
| | - Kayo Okazaki
- Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, no 2242, Cidade Universitária, CEP 05508-000, São Paulo, SP, Brazil
| | - Amanda Tosatte Granatelli
- Laboratório de Parasitologia/Malacologia, Instituto Butantan, Avenida Vital Brasil, 1500, CEP 05503-900, São Paulo, SP, Brazil
| | - Ivana Wuo Pereira
- Companhia de Saneamento Básico do Estado de São Paulo, R. Major Pinheiro Fróes, no 1.560, CEP 08680-000, Suzano, SP, Brazil
| | - Carlos Alberto de Bragança Pereira
- Departamento de Estatística, Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, no 1010, CEP 05008-090, São Paulo, SP, Brazil
| | - Eliana Nakano
- Laboratório de Parasitologia/Malacologia, Instituto Butantan, Avenida Vital Brasil, 1500, CEP 05503-900, São Paulo, SP, Brazil
| |
Collapse
|
3
|
Byzitter J, Lukowiak K, Karnik V, Dalesman S. Acute combined exposure to heavy metals (Zn, Cd) blocks memory formation in a freshwater snail. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:860-868. [PMID: 22218978 DOI: 10.1007/s10646-011-0847-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/17/2011] [Indexed: 05/31/2023]
Abstract
The effect of heavy metals on species survival is well documented; however, sublethal effects on behaviour and physiology are receiving growing attention. Measurements of changes in activity and respiration are more sensitive to pollutants, and therefore a better early indicator of potentially harmful ecological impacts. We assessed the effect of acute exposure (48 h) to two heavy metals at concentrations below those allowable in municipal drinking water (Zn: 1,100 μg/l; Cd: 3 μg/l) on locomotion and respiration using the freshwater snail, Lymnaea stagnalis. In addition we used a novel assessment method, testing the ability of the snail to form memory in the presence of heavy metals in both intact snails, and also snails that had the osphradial nerve severed which connects a chemosensory organ, the osphradium, to the central nervous system. Aerial respiration and locomotion remained unchanged by acute exposure to heavy metals. There was also no effect on memory formation of these metals when administered alone. However, when snails were exposed to these metals in combination memory formation was blocked. Severing the osphradial nerve prevented the memory blocking effect of Zn and Cd, indicating that the snails are sensing these metals in their environment via the osphradium and responding to them as a stressor. Therefore, assessing the ability of this species to form memory is a more sensitive measure of heavy metal pollution than measures of activity, and indicates that the snails' ability to demonstrate behavioural plasticity may be compromised by the presence of these pollutants.
Collapse
Affiliation(s)
- Jovita Byzitter
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, 2104 HSC Hospital Drive NW, Calgary, AB, Canada
| | | | | | | |
Collapse
|
4
|
Cui J, Shan B, Tang W. Effect of periphyton community structure on heavy metal accumulation in mystery snail (Cipangopaludina chinensis): a case study of the Bai River, China. J Environ Sci (China) 2012; 24:1723-1730. [PMID: 23520840 DOI: 10.1016/s1001-0742(11)60976-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The ratio of metal:P stoichiometry was used to identify the accumulation pathways of heavy metals (V, Cr, Co, Ni, Cu, Cd, and Pb) from periphyton to snails Cipangopaludina chinensis Gray (C. chinensis) in the Bai River watershed. The results showed that periphyton communities were mainly composed of two types of algae, filamentous green algae and unicellular diatoms. The proportion of unicellular diatoms in the periphyton community is a key factor that influences metal accumulation in C. chinensis. The V, Cr, Co, Ni, and Cd content of C. chinensis increased steadily as the corresponding metal content of periphyton increased, but Cu and Pb in the snail did not increase in the periphyton. Mechanisms of V, Cr, and Ni accumulation were found to be related to the proportion of diatoms, while Cd and Pb accumulation were dependent on the physiological characteristics of C. chinensis. The accumulation of Cu in C. chinensis was closely related to their grazing behavior. The metal: P stoichiometry revealed that Cr, Ni, and Cd can reduce the potential ecological risks associated with increased P inputs to the ecosystem. V and Co were considered to be relatively safe, regardless of the periphyton P content. Finally, Pb may not be prone to transfer to higher trophic levels, and may pose the lowest ecological risks of the studied heavy metals, but Cu can cause potential ecological risks when eutrophication has occurred.
Collapse
Affiliation(s)
- Jingguo Cui
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | | | | |
Collapse
|
5
|
Spade DJ, Griffitt RJ, Liu L, Brown-Peterson NJ, Kroll KJ, Feswick A, Glazer RA, Barber DS, Denslow ND. Queen conch (Strombus gigas) testis regresses during the reproductive season at nearshore sites in the Florida Keys. PLoS One 2010; 5:e12737. [PMID: 20856805 PMCID: PMC2939879 DOI: 10.1371/journal.pone.0012737] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 08/02/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Queen conch (Strombus gigas) reproduction is inhibited in nearshore areas of the Florida Keys, relative to the offshore environment where conchs reproduce successfully. Nearshore reproductive failure is possibly a result of exposure to environmental factors, including heavy metals, which are likely to accumulate close to shore. Metals such as Cu and Zn are detrimental to reproduction in many mollusks. METHODOLOGY/PRINCIPAL FINDINGS Histology shows gonadal atrophy in nearshore conchs as compared to reproductively healthy offshore conchs. In order to determine molecular mechanisms leading to tissue changes and reproductive failure, a microarray was developed. A normalized cDNA library for queen conch was constructed and sequenced using the 454 Life Sciences GS-FLX pyrosequencer, producing 27,723 assembled contigs and 7,740 annotated transcript sequences. The resulting sequences were used to design the microarray. Microarray analysis of conch testis indicated differential regulation of 255 genes (p<0.01) in nearshore conch, relative to offshore. Changes in expression for three of four transcripts of interest were confirmed using real-time reverse transcription polymerase chain reaction. Gene Ontology enrichment analysis indicated changes in biological processes: respiratory chain (GO:0015992), spermatogenesis (GO:0007283), small GTPase-mediated signal transduction (GO:0007264), and others. Inductively coupled plasma-mass spectrometry analysis indicated that Zn and possibly Cu were elevated in some nearshore conch tissues. CONCLUSIONS/SIGNIFICANCE Congruence between testis histology and microarray data suggests that nearshore conch testes regress during the reproductive season, while offshore conch testes develop normally. Possible mechanisms underlying the testis regression observed in queen conch in the nearshore Florida Keys include a disruption of small GTPase (Ras)-mediated signaling in testis development. Additionally, elevated tissue levels of Cu (34.77 ng/mg in testis) and Zn (831.85 ng/mg in digestive gland, 83.96 ng/mg in testis) nearshore are similar to reported levels resulting in reproductive inhibition in other gastropods, indicating that these metals possibly contribute to NS conch reproductive failure.
Collapse
Affiliation(s)
- Daniel J. Spade
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
| | - Robert J. Griffitt
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
| | - Li Liu
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida, United States of America
| | - Nancy J. Brown-Peterson
- Department of Coastal Sciences, University of Southern Mississippi, Ocean Springs, Mississippi, United States of America
| | - Kevin J. Kroll
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
| | - April Feswick
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
| | - Robert A. Glazer
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Marathon, Florida, United States of America
| | - David S. Barber
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
| | - Nancy D. Denslow
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| |
Collapse
|
6
|
Ma T, Gong S, Zhou K, Zhu C, Deng K, Luo Q, Wang Z. Laboratory culture of the freshwater benthic gastropod Bellamya aeruginosa (Reeve) and its utility as a test species for sediment toxicity. J Environ Sci (China) 2010; 22:304-13. [PMID: 20397422 DOI: 10.1016/s1001-0742(09)60109-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study aimed to develop original laboratory culture and sediment toxicity testing protocols for the freshwater gastropod Bellamya aeruginosa (Reeve), a new potential species for sediment toxicity testing. B. aeruginosa was successfully cultured with an effective culture system under proposed laboratory conditions. Optimal ad libitum feeding levels for larvae, juveniles, and adults were 2.0, 6.0, and 16.0 mg fish food/(snail x day), respectively. Mean survival rates of juveniles were higher than 90%. The snails could be sexed at 9 weeks of age, and their generation time is approximately 4 months. Reproduction continued all year around; the mean fecundity was 0.55 newborn/(female x day). The utility of this species for bioassays was evaluated in both 10-day and 28-day case studies with artificial sediments. The 10-day LC50 of Cu for larvae was 480 gg/g dry weight (dw), and the lowest observed effects concentration of Cu for survival and growth of larvae was 195 microg/g dw. Survival and growth are reliable indicators of acute toxicity. Larvae accumulated more Cu than adults. B. aeruginosa exhibited a higher sensitivity to Cu exposure than standard test species (Hyalella azteca and Chironomus tentans). The 28-day test of sediment toxicity with adults showed that fecundity was a robust endpoint indicator of reproductive toxicity, and the biochemical endpoints of superoxide dismutase, catalase, and glutathione could be used as sensitive biomarkers for Cu-induced oxidative damage. B. aeruginosa can be therefore recommended as a candidate for the standardization of the freshwater sediment toxicity test protocol.
Collapse
Affiliation(s)
- Taowu Ma
- College of Biology and Environmental Science, Jishou University, Jishou 416000, China.
| | | | | | | | | | | | | |
Collapse
|
7
|
Peralta-Videa JR, Lopez ML, Narayan M, Saupe G, Gardea-Torresdey J. The biochemistry of environmental heavy metal uptake by plants: Implications for the food chain. Int J Biochem Cell Biol 2009; 41:1665-77. [DOI: 10.1016/j.biocel.2009.03.005] [Citation(s) in RCA: 446] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 03/12/2009] [Accepted: 03/13/2009] [Indexed: 10/21/2022]
|
8
|
Libralato G, Avezzù F, Losso C, Volpi Ghirardini A. Influence of storage methods, refrigeration or freezing, on the toxicity of wastewater samples to oyster embryos. ENVIRONMENTAL TECHNOLOGY 2009; 30:535-541. [PMID: 19603701 DOI: 10.1080/09593330902831226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
One of the main concerns in wastewater whole effluent assessment is the sampling phase and the sample chain of custody before any toxicity evaluation. The major problem is related to establishing the correct method for sample storage in order to perform toxicity bioassays. The toxicity of some domestic and glass factory industrial wastewater samples stored both by refrigeration at 4 +/- 1 degrees C for no more than three days, and freezing at -18 +/- 1 degrees C for no more than one month was compared via the embryo larval development bioassay with the oyster Crassostrea gigas. The results showed no significant differences between the toxicities of refrigerated and frozen wastewater samples. The wastewater classification, according to a score based on four toxicity classes, showed that the preservation methods did not alter the toxicity classification of the samples. In particular, it was demonstrated that the samples considered as 'not acutely toxic' after refrigeration were also found to have this classification after freezing.
Collapse
Affiliation(s)
- G Libralato
- Environmental Sciences Department, University of Venice Cà Foscari, Campo della Celestia 2737/b, 1-30122 Venice, Italy.
| | | | | | | |
Collapse
|
9
|
Ansaldo M, Nahabedian DE, Di Fonzo C, Wider EA. Effect of cadmium, lead and arsenic on the oviposition, hatching and embryonic survival of Biomphalaria glabrata. THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:1923-1928. [PMID: 19108873 DOI: 10.1016/j.scitotenv.2008.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 11/19/2008] [Accepted: 12/01/2008] [Indexed: 05/27/2023]
Abstract
Biomphalaria glabrata is a widespread freshwater gastropod mollusc. The easy aquaculture of these organisms allow its use as an accessible tool for contamination bioassays. B. glabrata showed marked metabolic responses when exposed to cadmium, lead and arsenic. Those responses could also affect the reproduction of the snails. Taking into account this hypothesis, B. glabrata were exposed for 96 h (acute laboratory bioassays) to different concentrations of cadmium (0.1, 0.05 and 0 mg/L), lead (0.5, 0.1, 0.05 and 0 mg/L) and arsenic (0.5, 0.1, 0.05 and 0 mg/L). Snails were removed from the aquaria while eggs were left in the same contaminant concentrations. The effect of the assayed toxicants on snail reproduction was registered as the alterations of the total number of laid eggs (TNLE), hatching time and embryonic survival. At 0.10 mg/L cadmium significantly decreased the TNLE (p<0.05) and no embryos survived. The lowest assayed level (0.05 mg/L) of cadmium, delayed the hatching time twice when it was compared with the control group (p<0.01). Lead decreased the TNLE at 0.5 mg/L level (p<0.01). The other assayed doses (0.05 and 0.10 mg/L) also decreased embryonic survival significantly (p<0.05 and p<0.01 respectively) and extended twice the time to hatching (p<0.01). The 0.50 mg/L level killed all embryos. Arsenic at all studied concentrations decreased the TNLE (p<0.05) while the hatching time was increased by 50%. Embryo survival only decreased at the highest level (0.5 mg/L) of arsenic assayed. In summary, the acute exposure (96 h) to cadmium lead and arsenic, altered the reproduction of B. glabrata, modifying the TNLE, hatching time and embryonic survival.
Collapse
Affiliation(s)
- Martín Ansaldo
- Instituto Antártico Argentino, Dirección Nacional del Antártico, Cerrito 1248, (1010) Buenos Aires, Argentina.
| | | | | | | |
Collapse
|
10
|
Marchese M, Gagneten AM, Parma MJ, Pavé PJ. Accumulation and elimination of chromium by freshwater species exposed to spiked sediments. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2008; 55:603-609. [PMID: 18274820 DOI: 10.1007/s00244-008-9139-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 01/21/2008] [Indexed: 05/25/2023]
Abstract
The bioaccumulation and elimination capacity of chromium were examined in four freshwater species: the submersed aquatic plant Ceratophyllum demersum (Ceratophyllaceae), the oligochaete Limnodrilus udekemianus (Tubificidae), the crab Zilchiopsis collastinensis (Decapoda), and the fish Cnesterodon decemmaculatus (Poeciliidae). All of the species were exposed simultaneously to sediments spiked with Cr (K(2)Cr(2)O(7)) at different concentrations for 28 days, followed by 7 days without Cr to evaluate the concentration of residual Cr. We found that Cr accumulated in the tissues of all four species. The highest bioconcentration factor obtained for each species is as follows: C. demersum, 718.66 (+/-272.91); L. udekemianus, 172.55 (+/-80.8), Z. collastinensis, 67.72 (+/-35.4); C. decemmaculatus, 23.11 (+/-12.82), all at 28 days of exposure.
Collapse
Affiliation(s)
- Mercedes Marchese
- Instituto Nacional de Limnología-INALI (CONICET-UNL), José Maciá 1933, 3016, Santo Tomé, Santa Fe, Argentina.
| | | | | | | |
Collapse
|
11
|
Bernard A. Biomarkers of metal toxicity in population studies: research potential and interpretation issues. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1259-65. [PMID: 18654897 DOI: 10.1080/15287390802211885] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biomarkers of effects are molecular tools that can serve to identify changes or effects occurring in the organism because of exposure to a given toxicant or stressor. The potential of biomarkers of effects in epidemiology resides mainly in their greater sensitivity and specificity as compared with more traditional endpoints. Noninvasiveness and objectivity are also important features of effect biomarkers that allow minimizing of the risks of participation and response biases in population studies. Since effect biomarkers are not specific for a given metal, they should always be used in combination with biomarkers or tests of exposure. Dose-response/effect relationships emerging between effect and exposure biomarkers should be carefully analyzed in order to avoid confounding by sampling conditions, subjects' characteristics or lifestyle, or else recent changes in exposure levels. It is also important to exclude the possibility of secondary associations, as well as to make sure that metal exposure is the cause of the effect and not the opposite (reverse causality). Assessing the health significance of associations between effect biomarkers and metal exposure is a delicate task, which necessarily implies some personal judgment. Factors to consider in this exercise include the magnitude and type of adverse effect, the possibility of some reversal, the strength of associations, and the type and size of populations at risk.
Collapse
Affiliation(s)
- Alfred Bernard
- Department of Public Health, Catholic University of Louvain, Brussels, Belgium.
| |
Collapse
|
12
|
Ra JS, Kim HK, Chang NI, Kim SD. Whole effluent toxicity (WET) tests on wastewater treatment plants with Daphnia magna and Selenastrum capricornutum. ENVIRONMENTAL MONITORING AND ASSESSMENT 2007; 129:107-13. [PMID: 17106776 DOI: 10.1007/s10661-006-9431-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2005] [Revised: 01/20/2006] [Accepted: 03/09/2006] [Indexed: 05/12/2023]
Abstract
Whole effluent toxicity (WET) tests, with Daphnia magna and Selenastrum capricornutum, were introduced to evaluate the biological toxicities of effluents from the wastewater treatment plants (WWTPs) in Korea. In WET tests of WWTPs effluents, 33.3% (33/99) for D. magna and 92.6% (75/81) for S. capricornutum revealed greater than 1 toxic unit (TU), even though all the treatment plants investigated were operating in compliance with the regulations, as assessed using conventional monitoring methods (i.e., BOD and total concentration of N or P, etc). There were only minor differences in toxicities according to the types of influents (municipal and agro-industrial) in all treatment plants. However, the effluents treated by an activated sludge treatment process were found to exhibit significantly lower toxicity than those treated by rotating biological contactor (RBC) and extended aeration processes. The seasonal variations in the toxicity were lower in the summer compared to winter, which may have been due to the rainfall received to the sewage intake system during the former period. The impact of WET on river water was also investigated based on the discharge volume. At sites A and B, the total impact of toxicity to stream and river waters was observed to be 70.9% and 90.4% for D. magna and S. capricornutum, respectively. The other four small treatment plants (sites F, G, H and I), with relative discharging volumes between 0.001 and 0.002, contribute less than 1% to the total toxicity.
Collapse
Affiliation(s)
- Jin Sung Ra
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
| | | | | | | |
Collapse
|
13
|
|