This study involved the development and evaluation of a number of biomonitoring
techniques for use with members of the Ulvaceae, Enteromorpha intestinalis (L.) Link, and
Viva lactuca (L.). The techniques included both previously established ones and those
which required development. The two main procedures developed for these algae were the
neutral red retention technique (making use of a vital stain) and the ion leakage Health
Index (based upon electrolyte leakage). Following optimisation both were used to produce
quantitative structure-activity relationships (QSARs) for a series of n-alcohols using log KOW
as the physicochemical parameter. The resultant QSARs were statistically indistinguishable
with line equations of -0.88 log KOW + 2.87 and -0.95 log KOW + 2.83 respectively, with
r² values of 0.98, suggesting that both reflect the same non-specific narcotic effect on
membrane integrity. However the neutral red retention technique was less useful than the
Health Index with low reproducibility and is therefore unsuitable for use as an
environmental biomonitor.
The effects of other compounds with specific modes of action were established using the
ion leakage technique, the high toxicity of the antifouling compound tributyltin being
reflected in the Health Index. Further development of the ion leakage technique involved
inductively coupled - plasma mass spectrometry (ICP/MS) in the identification of ions lost
during leakage. Synergistic toxicity was investigated exposing the algae to UV light and
anthracene, simulating photo-induced toxicity. No photo-induced toxicity was observed
although UV exposure did reduce the Health Index.
An environmental assessment was carried out for algae from clean sites and organically
and inorganically polluted sites, comparing the Health Index with other measures of health
and bioaccumulation data. A long term study of a clean site showed the algal Health Index
to be influenced by seasonally dependent physical parameters, but reflected reduced health
in algae exposed environmentally to organic pollutants. Algae exposed to long term heavy
metal pollution in the Fal Estuary had 'normal'. Health Indices, however chlorophyll
fluorescence induction techniques did highlight a reduced photosynthetic efficiency in these
algae.
The ion leakage technique has potentially a wide application in field and laboratory based
biomonitoring and direct toxicity studies. Chlorophyll fluorescence analysis was also shown
to be useful although it requires further investigation and evaluation.
Date of Award | 1996 |
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Original language | English |
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Awarding Institution | |
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Evaluation of Techniques For The Biomonitoring of Pollutants in Members of The Ulvaceae
Schild, R. (Author). 1996
Student thesis: PhD