Screening and testing for endocrine disruption in fish-biomarkers as "signposts," not "traffic lights," in risk assessment

Biomarkers are currently best used as mechanistic "signposts" rather than as "traffic lights" in the environmental risk assessment of endocrine-disrupting chemicals (EDCs). In field studies, biomarkers of exposure [e.g., vitellogenin (VTG) induction in male fish] are powerful tools for tracking single substances and mixtures of concern. Biomarkers also provide linkage between field and laboratory data, thereby playing an important role in directing the need for and design of fish chronic tests for EDCs. It is the adverse effect end points (e.g., altered development, growth, and/or reproduction) from such tests that are most valuable for calculating adverseNOEC (no observed effect concentration) or adverseEC10 (effective concentration for a 10% response) and subsequently deriving predicted no effect concentrations (PNECs). With current uncertainties, biomarkerNOEC or biomarkerEC10 data should not be used in isolation to derive PNECs. In the future, however, there may be scope to increasingly use biomarker data in environmental decision making, if plausible linkages can be made across levels of organization such that adverse outcomes might be envisaged relative to biomarker responses. For biomarkers to fulfil their potential, they should be mechanistically relevant and reproducible (as measured by interlaboratory comparisons of the same protocol). VTG is a good example of such a biomarker in that it provides an insight to the mode of action (estrogenicity) that is vital to fish reproductive health. Interlaboratory reproducibility data for VTG are also encouraging; recent comparisons (using the same immunoassay protocol) have provided coefficients of variation (CVs) of 38-55% (comparable to published CVs of 19-58% for fish survival and growth end points used in regulatory test guidelines). While concern over environmental xenoestrogens has led to the evaluation of reproductive biomarkers in fish, it must be remembered that many substances act via diverse mechanisms of action such that the environmental risk assessment for EDCs is a broad and complex issue. Also, biomarkers such as secondary sexual characteristics, gonadosomatic indices, plasma steroids, and gonadal histology have significant potential for guiding interspecies assessments of EDCs and designing fish chronic tests. To strengthen the utility of EDC biomarkers in fish, we need to establish a historical control database (also considering natural variability) to help differentiate between statistically detectable versus biologically significant responses. In conclusion, as research continues to develop a range of useful EDC biomarkers, environmental decision-making needs to move forward, and it is proposed that the "biomarkers as signposts" approach is a pragmatic way forward in the current risk assessment of EDCs.

Seawater carbonate chemistry, clearance rates, respiration rates, condition index and cellular turnover (RNA: DNA) of Juvenile King Scallop, Pecten maximus in a laboratory experiment

The decline in ocean water pH and changes in carbonate saturation states through anthropogenically mediated increases in atmospheric CO2 levels may pose a hazard to marine organisms. This may be particularly acute for those species reliant on calcareous structures like shells and exoskeletons. This is of particular concern in the case of valuable commercially exploited species such as the king scallop, Pecten maximus. In this study we investigated the effects on oxygen consumption, clearance rates and cellular turnover in juvenile P. maximus following 3 months laboratory exposure to four pCO2 treatments (290, 380, 750 and 1140 µatm). None of the exposure levels were found to have significant effect on the clearance rates, respiration rates, condition index or cellular turnover (RNA: DNA) of individuals. While it is clear that some life stages of marine bivalves appear susceptible to future levels of ocean acidification, particularly under food limiting conditions, the results from this study suggest that where food is in abundance, bivalves like juvenile P. maximus may display a tolerance to limited changes in seawater chemistry.

Xenophontis Cyropaedia,

Mode of access: Internet.

Buenos Aires y otras provincias arjentinas, con estractos de un diario de la esploración del Río Salado en 1862 y 1863,

Translation of: Buenos Ayres and Argentine gleanings.

Les americaines ou la preuvre de la religion chrétienne ... /

Mode of access: Internet.

Magazin des adolescentes, ou Dialogues entre une sage gouvernante, et plusieurs de ses élèves de la première distinction /

Mode of access: Internet.

Conversaciones familiares de doctrina christiana : tomo IV /

Mención de responsabilidad y año de publicación tomadas de la port. grab.

Conversaciones familiares de doctrina christiana entre gentes del campo, artesanos, criados, y pobres /

Mode of access: Internet.

"Xenophōntōs Kyrou paideias biblia oktō." Xenophontis De Ciri institutione libri octo.

Words between quotation marks transliterated from Greek.

Buenos Ayres and Argentine gleanings: with extracts from a diary of Salado exploration in 1862 and 1863.

Title vignette.

The works of the Right Rev. William Beveridge, with a memoir of the author, and a critical examination of his writings

v. l. Memoir of the life of the author, including critical remarks on his writings. The church catechism explained. Private thoughts on religion. Resolutions formed upon the foregoing articles. Private thoughts upon religion, pt. II. The great advantage and necessity of public prayer. The great necessity and advantage of frequent communion. A defence of the book of Psalms, collected into English metre, by Thomas Sternhold, John Hopkins, and others. Indexes.--v. 2-6. Sermons.--v.7-8 Thesaurus theologicus.--v.9. An exposition of the Thirty-nine articles of the Church of England.

Lettres d'Émérance à Lucie,

Mode of access: Internet.

The Zulus of Natal ; The Niger, Tshadda and Binuë.

Contains Life with the Zulus of Natal, South Africa / by G.H. Mason (London, 1855) and Narrative of the Niger, Tshadda, & Binuë exploration / by T.J. Hutchinson (London, 1855)

Cartas de Emeranza á Lucía /

Contiene: T. I (412 p.) - T. II (392 p.)

Almacén y biblioteca completa de los niños o Diálogos de una sabia directora con sus discípulas de la primera distinción /

Contiene: vol. 1 - vol. 2 - vol. 3