WWW.DISSERTATION.XLIBX.INFO
FREE ELECTRONIC LIBRARY - Dissertations, online materials
 
<< HOME
CONTACTS



Pages:     | 1 |   ...   | 4 | 5 || 7 |

«RECETOX Research Centre for Environmental Chemistry and Ecotoxicology Laboratory tests of toxicity with enchytraeids RIGOROUS THESIS Brno, 2007 MSc. ...»

-- [ Page 6 ] --

Five replicates for control (without chemical) + 5 replicates for acetone + 5 replicates for each concentration was prepared. At the start of test, dry oat flakes (food) was mixed with soil and 10 adults with clitellum were introduced into the test vessel. The test vessels were closed by lid and were stored by 20 ± 2 0C and under 16/8 light–dark cycle. The food was added every week into the soil. At the end of test, the worms were killed by ethanol (5 ml) and coloured by Bengal red. The next day, the survival of adults and number of juveniles were manually counted.

–  –  –

Statistical analyses Program STATISTICA 6.0 software (StatSoft, Inc., 2004) was used for data evaluation.

No observed effect concentration (NOEC) was determined by analysis of variance (ANOVA) and Dunnett’s procedure at a 5% significant level. The concentration at which x% of adult survival was observed (LCx) and x% effect concentration for the reproductive output (ECx) were calculated according to Haanstra et al. (Haanstra et al., 1985) using logistic regression analysis.

2.1.4. Results and discussion Short-chain chlorinated paraffins The results indicate that SCCPs did not affect enchytraeid survival for species Enchytraeus albidus. The 30% mortality was occured in test with E. crypticus. From this reason, LC50 values could not be estimated. Reproduction was more sensitive endpoint than survival of adults. The EC50 = 6,027 (3,576-8,478) mg/kg and 7,809 (4,381-11,237) mg/kg were estimated for E. albidus and E. crypticus, respectively.

( ) Figure 1. Toxicity test with Short-chain chlorinated paraffins (SCCPs) and enchytraeid species E.

albidus. The results (adult mortality and reproduction = number of juveniles) are expressed as mean values ± standard error (SE), n = 5 replicates.

33 In conclusion, the used species were similarly low sensitive to SCCPs exposure in the artificial soil. In addition, the results are in a good accordance with the data from literature (Sverdrup et al., 2006a). They tested SCCPs in an agricultural soil (1.6 % of organic carbon) with species E. crypticus. Similarly, the highest test concentration (1,000 mg/kg) has not any effect on enchytraeid survival and reproduction in their test (Sverdrup et al., 2006a).

( ) Figure 2. Toxicity test with Short-chain chlorinated paraffins (SCCPs) and enchytraeid species E.

crypticus. The results (adult mortality and reproduction = number of juveniles) are expressed as mean values ± standard error (SE), n = 5 replicates.

Its possible that low toxicity of SCCPs to enchytraeids is influenced by their relatively high molecule (Mw = 320-500), their low water solubility (0.15-0.47 mg/l) and high sorption into soil matter. In any case, SCCPs most probably does not cause negative effects for enchytraeids in soils.

Toxaphene

The results of test with toxaphene are showed in the figure 3. Adult survival and reproduction (number of juveniles) were not markedly affected in the highest test concentration and LC50/EC50 values could not be estimated. Nevertheless, the NOEC values (620 mg/kg) for both the endpoints were estimated by ANOVA analysis at least. The species Enchytraeus albidus was similarly unsensitive to tested pesticide as well as the second enchytraeid species E. crypticus (see Table 2 in the Appendix II.)(the toxaphene test with E.

crypticus was made by Dr. Bezchlebová and from this reason, the results from this experiment are not presented in the chapture „Results and disccusion“ of my rigorous thesis but they are only included in the appropriate article – see Appendix II.). Unfortunatelly, there are no literature data on toxaphene toxicity to soil enchytraeids under laboratory test condition and hence, the data on enchytraeids are compared with the results from the other invertebrate tests from the mentioned article.

–  –  –

The both enchytraeids species were unsensitive to toxaphene exposure in comparison to the other test invertebrates as springtails, earthworms or nematodes (see Appendix II.). The sensitivity of invertebrates decresing in the order: springtails earthworms nematodes

enchytraeids. The possible explanation for the results could be:

1. Toxaphene is an insecticide with more specific mode of toxic action (neurotoxicity) and that is why springtails (Arthropoda: Hexapoda) could be more sensitive than worms.

2. It has been shown that arthropods are able to metabolise pollutants better than soil worms (van Brummelen and van Straalen, 1996) which have higher tendency to bioaccumulation (Jager et al., 2000) and biotransforming animals could be more sensitive to than bioaccumulating ones (Van Straalen, 2004).

3. Lower bioavailability of low soluble toxaphene to soil enchytraeids via soil pore water however, these possibilities did not explain the higher toxicity of toxaphene to earthworms or nematodes.

The sensitivity of nematodes would have been decreased if we had used the OECD soil in nematode test as well as in enchytraeid test. The used natural soil with the lower content of organic matter and different design of nematode test could finally increased bioavailability and toxicity of toxaphene to nematode worms in comparison to enchytraeids in OECD soil with a higher content of organic matter (see Table 2 in Appendix II.). On the other hand, the various toxicity betwen oligochaetes (earthworms versus enchytraeids) could not be explained satisfactory. In some studies (Römbke et Moser, 2002), the sensitivity of earthworms and enchytraeids to various chemicals was comparable but in the others, earthworms were more sensitive than their smaller relatives (Sverdrup et al., 2002b). There, one explanation is maybe disposable: smaller enchytraeids are in very close contact with soil pore water similarly as nematodes (Achazi et van Gestel, 2003) but bigger earthworms may uptake more toxaphene via ingestion of contaminated soil particles and food (horse manure) due to a higher sorption of toxaphene into solid phase (organic matter) in comparison to soil pore water. These hypothesis are partly supported by a field study, where the decreasing of abundance was 35 attributed to indirect effect via lack of food (this aspect was not relevant in our study because all organisms had enough food during the individual test periods) or toxaphene exposure via ingestion or a sensitivity of studied organisms (Bäumler et al., 1978 in Didden et Römbke, 2001).





N-polycyclic aromatic hydrocarbons (NPAHs) The dose response curves were different for the individual compounds (see Figure 4-7).

The effect of compounds on adult survival was in the same order of magnitude, nevertheless their toxicity decreased in the rank: 1,10-phenanthroline quinoline ≥ phenazine ≥ acridine.

The reproduction was more sensitive endpoint than survival of adults. The toxicity of compounds decreased nearly in the same rank as at survival: 1,10-phenanthroline ≥ quinoline phenazine acridine. The LC50 and EC50 values are described in the Table 15.

–  –  –

4 400 2 200 0 0 0 100 500 1000 1500 2000 2500 ( ) Figure 4. Toxicity test with Quinoline and enchytraeid species E. crypticus. The results (adult mortality and reproduction = number of juveniles) are expressed as mean values ± standard error (SE), n = 5 replicates.

36 10 500

–  –  –

) Figure 6. Toxicity test with Phenazine and enchytraeid species E. crypticus. The results (adult mortality and reproduction = number of juveniles) are expressed as mean values ± standard error (SE), n = 5 replicates.

37 10 500

–  –  –

The effects of phenazine and 1,10-phenanthroline on soil enchytraeids have never been studied. Thus, comparison with the literature data is possible only for acridine and quinoline, which have been tested in two studies among some other PAHs (Sverdrup et al. 2002b;

Bleeker et al., 2003). It was found that acridine has lower toxic effects than quinoline (Bleeker et al., 2003) and this is in agreement with our data (compare Table 15 and 16).

Toxicity described in this holand work (Bleeker et al., 2003) was also higher than toxicity in our study. This might be related to the lower organic matter content in natural soil using in Bleker´s study. Surprisingly, the results from the second study (Sverdrup, 2002b) were relatively similar to ours but reason for that remains unclear (toxicity from this study should have been the highest in comparison with Bleker´s and our results due to the lowest organic carbon content of agricultural soil - see Table 16).

–  –  –

It is very well known that only bioavailable part of nominal concentration (mg/kg) applied to soil could cause toxicity to soil organisms. The bioavailability of compounds is influenced by many factors as structure of chemicals, physico-chemical properties of soil and 38 surrounding environment, ageing and sensitivity of the test species (e.g. Lanno, 2003). No less importance have also the exposure pathways for the organism (uptake of chemical in or on an organism). Enchytraeids could be exposed via contaminated food or soil pore water whereas contamination through a gase phase is mostly neglectable (Achazi et van Gestel, 2003). The pore-water exposure is treated as the most important route because oligochaete worms are in close contact with soil solution. The exposure via contaminated food raises significance rather for compounds with higher lipophilicity (Log Kow over 5.5) (Achazi et van Gestel, 2003).

All organic compounds are able to cause narcosis and many studies have shown that narcosis is strongly related to the lipophilicity of the compound, expressed as the n-octanolwater partitioning coefficient = Log Kow (e.g. Chen et al., 1997). These conclusions were confirmed in aquatic as well as terrestrial environment (e.g. Sverdrup et al., 2002c; Bleeker et al., 2003). The effective concentration from soil tests of toxicity has been more often

overestimated on effective concentration in soil pore-water according to the formula:

–  –  –

where:

L(E)Cwater (mmol/L) = effective concentration in soil pore-water, L(E)Csoil (mg/kg) = nominal effective concentration in soil, Mw = molecular weight, Kd = partitioning coefficient soil-water (overtaken from Sverdrup et al., 2002c).

Theoretically, this concentration express the concentration of compound in soil porewater that may cause the x% effect in soil. However, the using of this method assumes that organisms are exposed exclusively via pore water in soils. The other disadvantage is that the final value (LC or EC(mmol/L)) is strongly influenced by Kd value of the test soil. This aspect makes comparison the experimental data with the data from literature more difficult because the coefficients often differs in orders of magnitude due to the various physico-chemical properties of used soils and different values of experimental or estimated Log Koc (e.g.

Doucette, 2003).

In my study, the recalculated L(E)Cwater ( mol/L) values showed the opposite toxicity in comparison to primary results from the tests. Acridine was the most toxic compounds followed by phenazine, quinoline and the least toxic compound seemed to be 1,10phenanthroline (see Table 15). It is obvious that the more lipophilic compounds may potencially cause the higher toxicity as well as in the aquatic tests (e.g. Bleeker et al., 2003).

The similar conclusions were found also for soil nematodes in aquatic test of toxicity (Sochová et al., in press). Nematode species Caenorhabditis elegans was sensitive to tested compounds in this order (from the most toxic to the least toxic compound): acridine phenazine 1,10-phenanthroline quinoline. On the other hand, the nematode LC50 values (Sochová et al., in press) were one or two orders of magnitude higher than the overestimated LC50 values for enchytreids in my tests. This could be caused the different design of the both tests (duration of test, species sensitivity, water or soil medium, etc.). The EC10 = 1.77 ( mol/L) from the other test with E. crypticus (Sverdrup et al., 2002b) showing lower toxicity for acridine in their Danish natural soil in comparison with toxicity in artificial soil from my study. However, the comparison of my data with the ones from acute aquatic tests with Chironomus riparius (Bleeker et al., 2003) showed almost the same toxicity for acridine (LC50 value = 0.4 mol/L) (compare with Table 15) and about one order of magnitude higher for quinoline (LC50 value = 37.9 mol/L) for larvae of chironomids (Bleeker et al., 2003).

Their results of toxicity for Chironomus riparius were also very well in accordance with the 39 EC50 values for E. crypticus in pore-water in LUFA 2.2 soil from the same study (Bleeker et al., 2003). On the other hand, the toxicity from acute or chronic aquatic tests with daphnids showed higher differencies in toxicity (one order of magnitude lower, higher or in the same order of magnitude) as for enchytraeids for different NPAHs (Feldmannová et al., 2006). In addition, these findings are relevant for narcosis but NPAHs are thanks to incorporation of nitrogen atom candidates also for the more specific mode of toxic action. Nevertherless, NPAHs indicated rather narcosis to soil invertebrates in the present available studies (Sverdrup et al., 2002b,c; Bleeker et al., 2003).

402.1.5. References

Adams, J. and Giam, C. S. (1984): Polynuclear azaarenes in wood preservative wastewater.

Environmental Science and Technology, 18: 391-394.

Adrian, N. R., Suflita, J. M. (1994): Anaerobic biodegradation of halogenated and nonhalogenated N-, S-, and O-heterocyclic compounds in aquifer slurries.

Environmental Toxicology and Chemistry, 13: 1551-1557.

ATSDR (1998): Toxicological profile for toxaphene. Atlanta, GA, Agency for Toxic Substances and Disease Registry. Centre for Desease Control and Prevention.

Bidleman, T. F., Patton, G. W., Walla, M. D., Hargrave, B. T., Vass, W. P., Erickson, P., Fowler, B., Scott, V., Gregor, D. J. (1989): Toxaphene and other organochlorines in Arctic Ocean fauna: evidence for atmospheric delivery. Arctic, 42: 307–313.

Bleeker, E. A. J. (1999): Toxicity of Azaarenes: Mechanisms and Metabolism. Disertation thesis. Universiteit van Amsterdam, Amsterdam, The Netherlands. 145 pp.



Pages:     | 1 |   ...   | 4 | 5 || 7 |


Similar works:

«SCHOOLS: Studies in Education Fall 2005 The (Progressive) Schools Our Children Deserve By Alfie Kohn [This is a transcript of the keynote address for a conference on progressive education sponsored by the School in Rose Valley and held at Swarthmore College on October 7, 2004.] I’m delighted to be with what I will presumptuously assume is a friendly crowd, such that the kinds of criticisms I offer of traditional schooling are not seen as offensive or even terribly surprising. That creates a...»

«A report on the Commonwealth Ombudsman’s activities under Part V of the Australian Federal Police Act 1979 FOR THE PERIOD 1 JULY 2014 TO 30 JUNE 2015 February 2016 Report by the Commonwealth Ombudsman under the Australian Federal Police Act 1979 2014-15 Annual Report on the Commonwealth Ombudsman’s activities under Part V of the Australian Federal Police Act 1979 ISSN 1835-3290 © Commonwealth of Australia 2016 The Commonwealth owns the copyright in all material produced by the Ombudsman....»

«Katherine M. Clabeaux Garden Program Sustainability Spring 2013 Planting Seeds of Knowledge: Sustainability of San Francisco Bay Area School Garden Programs Katherine M. Clabeaux ABSTRACT Historically, Untied States school garden programs have existed to augment classroom education. Previously conducted studies have proven the efficacy of using school garden programs as an educational tool, however these studies have not examined the sustainability of using garden programs long-term. To...»

«TREASURY INSPECTOR GENERAL FOR TAX ADMINISTRATION Affordable Care Act: Controls Over Financial Accounting for the Premium Tax Credit Should Be Improved March 2, 2016 Reference Number: 2016-13-021 This report has cleared the Treasury Inspector General for Tax Administration disclosure review process and information determined to be restricted from public release has been redacted from this document.. Phone Number / 202-622-6500 E-mail Address / TIGTACommunications@tigta.treas.gov Website /...»

«6.045J/18.400J: Automata, Computability and Complexity Prof. Nancy Lynch, Nati Srebro 6.045 Final Exam Solutions May 18, 2004 Susan Hohenberger Name: • Please write your name on each page.• This exam is open book, open notes.• There are two sheets of scratch paper at the end of this exam.• Questions vary substantially in difficulty. Use your time accordingly. • If you can not produce a full proof, clearly state partial results for partial credit. • Good luck! Problem Points Grade 1...»

«The Thinning of Arctic Sea Ice, 1988-2003: Have We Passed a Tipping Point? R. W. Lindsay and J. Zhang Polar Science Center, University of Washington, Seattle, WA Submitted to Journal of Climate, 12 November 2004 Accepted 21 June 2005 ABSTRACT Recent observations of summer arctic sea ice over the satellite era show that record or near record lows for the ice extent occurred in the years 2002–2004. To determine the physical processes contributing to these changes in the arctic pack ice, we...»

«HOCKING COLLEGE BOARD OF TRUSTEES MEETING Tuesday, December 15,2009 HOCKING 5:00 P.M. COLLEGE Inn at Hocking College AGENDA Call to Order Trustee Geiger o Trustee Geiger Administering the Oath of Office o Roll Call Trustee Swart o Trustee Geiger Approval of Minutes o Enrollment Report Dr. Short o Academic Committee Report Trustee Light! o Dr. Weiland • Information 1. Academic calendars for 2010-11 and 2011-12 Budget Committee Report Trustee Willard/ o Dr. Hill • Information ) 1. Monthly...»

«Gene expression under cold stress in Arabidopsis Item type text; Dissertation-Reproduction (electronic) Authors Lee, Byeong-ha Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Downloaded 16-Nov-2016...»

«Taiwan Journal of Linguistics Vol. 8.2, 63-86, 2010 CLAUSAL INTEGRATION AND THE EMERGENCE OF MITIGATIVE  AND ADHORTATIVE SENTENCE-FINAL PARTICLES IN CHINESE Foong Ha Yap, Jiao Wang, Charles Tsz-kwan Lam ABSTRACT This paper identifies a number of different pathways that give rise to sentence final particles in Chinese. In particular, it focuses on a strategy referred to as ‗clausal integration‘. Diachronic evidence is given for the emergence of sentence final particles er yi yi and ye yi...»

«REFERENCIA: Díez Pampliega, Cristina (2010). Mecanismos en el proceso de privatización de la enseñanza pública.REIFOP, 13 (2), 80-87. (Enlace web: http://www.aufop.com/ Consultada en fecha (dd-mm-aa): Mecanismos en el proceso de privatización de la enseñanza pública Cristina DÍEZ PAMPLIEGA RESUMEN Correspondencia En el ejemplo del distrito de Puente de Vallecas, se Cristina Díez Pampliega observa cómo el progresivo desarrollo de la red de enseñanza concertada en detrimento de la red...»

«PNNL-13281 Comparison of Nozzles and Flow Straighteners for Tank Waste Sluicing Applications O. D. Mullen D. R. Jackson September 2000 Prepared for The U.S. Department of Energy Under Contract DE-AC06-76RLO 1830 This work is funded by the Office of Science and Technology within the U.S. Department of Energy's Office of Environmental Management under the Tanks Focus Area Program DISCLAIMER This report was prepared as an account of work sponsored by an agency of the Unit Government. Neither the...»

«SUBURBAN REVISIONS A Thesis Presented to The Academic Faculty By Alyssa Shank Durden In Partial Fulfillment Of the Requirements for the Degree Master of Architecture I Georgia Institute of Technology August, 2005 SUBURBAN REVISIONS Approved by: Richard Dagenhart, Advisor College of Architecture Michael Dobbins College of Architecture Michael Gamble College of Architecture Date Approved: May 16, 2005 ii to my grandmother, Mary Ellen Shank, who inspired me to write and encouraged me to draw since...»





 
<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.