Henrik Holbech

Henrik Holbech
University of Southern Denmark | SDU · Department of Biology

PhD

About

90
Publications
10,411
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Introduction
Henrik Holbech currently works at the Department of Biology, University of Southern Denmark. Henrik does research in Xenobiology and Endocrinology. Current projects include 'Improvement of methodologies involved in assessment of organism viability in ships' treated ballast water contributing to overall quest in preventing the spreading of aquatic invasive species' and the EU Horizon 2020 project, ERGO, investigating new biomarkers and endpoints to identify thyroid disrupting chemicals in different vertebrate classes including mammals, fish and amphibians.

Publications

Publications (90)
Article
This review examines the presence and evolution of thyroid‐like systems in selected aquatic invertebrates with a view to the potential use of these organisms in screens for vertebrate thyroid hormone axis disrupting chemicals (THADCs). Such a screen might assist the phasing‐out of some vertebrate testing. Although arthropods including crustaceans d...
Article
The estrogenic activity of the chemical UV-filters, 4-methylbenzylidene camphor (4-MBC) and octyl methoxy cinnamate (OMC) was investigated in an in vivo rainbow trout (Oncorhynchus mykiss) assay. Plasma vitellogenin concentrations were quantified by means of an Enzyme Linked Immuno Sorbent Assay (ELISA) in juvenile rainbow trout before and after in...
Article
Full-text available
The thymus is present in all gnathostome vertebrates and is an essential organ for the adaptive immune system via the generation of functional mature T‐cells. Over the life span of mammals, the thymus undergoes morphological and functional alterations, including an age‐related involution, which in humans starts in early life. Life history tradeoffs...
Article
To comply with regulations stated by the United Nation’s International Maritime Organization, ballast water discharged by ships must be treated to avoid the spread of invasive organisms including algae. In this study, Raman spectroscopy and multivariate data analysis was used to make a Partial Least Squares Discriminant Analysis (PLS-DA) classifica...
Article
A growing number of environmental pollutants are known to adversely affect the thyroid hormone system, and major gaps have been identified in the tools available for the identification, and the hazard and risk assessment of these thyroid hormone disrupting chemicals. We provide an example of how the adverse outcome pathway (AOP) framework and assoc...
Article
Full-text available
ERGO (EndocRine Guideline Optimization) is the acronym of a European Union-funded research and innovation action, that aims to break down the wall between mammalian and non-mammalian vertebrate regulatory testing of endocrine disruptors (EDs), by identifying, developing and aligning thyroid-related biomarkers and endpoints (B/E) for the linkage of...
Article
Full-text available
To limit the spreading of aquatic invasive species, regulations require ships’ ballast water to be treated before discharge. To validate ballast water treatment system (BWTS) performance, treated water is analyzed for living organisms in different size classes. Quantitative assessment of the size class 10–50 μm (mainly phytoplankton) is carried out...
Article
Vitellogenin (VTG), a well-established biomarker for the diagnosis of endocrine activity in fish, is used in multiple OECD test guidelines (TG) to identify activities of chemicals on hormonal pathways. However, the synthesis of VTG may not only be modified by typical endocrine-related pathways, but also through non-endocrine-mediated processes. In...
Article
The International Ballast Water Management (BWM) Convention entered into force in September 2017. In the convention, the International Maritime Organization (IMO) required two options: ballast water exchange (BWE) standard D-1, and ballast water performance standard D-2 which required ballast water treatment systems (BWTSs). We explored the impact...
Article
To challenge ballast water treatment system (BWTS) efficacy for organisms in the size-class 10-50 μm, intake concentration during tests must reach certain minimum requirements. Often, natural concentrations are too low to meet intake requirements and standard test organisms (STOs) are added. We tested the robustness of Tetraselmis suecica and Odont...
Article
This study investigates the extra UV fluence needed to meet the International Maritime Organisation's ballast water discharge standards for the 10-50 μm size-class using the approved vital stain (VS) method compared to the Most Probable Number (MPN) method for organism viability assessment. Low-and medium pressure UV collimated beam treatments were...
Chapter
Not all designed experiments in toxicology follow the simple dose–response designs that have been the subject of earlier chapters, where the only relevant factors are dose (or concentration) and replicate. Other factors sometimes must be considered. This chapter will deal with controlled and uncontrolled factors that should be taken into account to...
Chapter
Regression modeling of toxicity data is increasingly required in the ecotoxicology community. The advantages of regression over hypothesis testing have been promoted by numerous authors. It is not the purpose of this chapter to explore the relative merits of hypothesis testing and regression modeling to evaluate ecotoxicity data. Rather, we present...
Chapter
This chapter describes different structures of, and approaches to, regulatory testing of chemicals. Focus is on standardized test guidelines and testing strategies with the use of the Organisation for Economic Co‐operation and Development (OECD) and US Environmental Protection Agency (USEPA) test guidelines as examples. If a more detailed and compr...
Chapter
Some regulatory test guidelines call for the determination of an NOEC for one or more responses, and it is important to understand the statistical models that are available for this purpose. This requires an understanding of the experimental designs that support these tests, the properties, such as power and sensitivities of the tests, and the limi...
Chapter
Survival analysis is one type of time‐to‐event analysis that has received considerable attention for many years. Chapter 8 introduced responses such as time to swimup and time to metamorphosis and developed some simple models for their analysis. In this chapter, other statistical methods for analyzing time‐to‐event data will be developed. These inc...
Chapter
This chapter is concerned with the estimation of effects concentrations, EC/LCx, for quantal responses. The focus will be on regression models that can be used for this purpose. The primary models used for quantal data in regulatory risk assessment are the probit and logistic models, but other models will be considered, including Weibull, and model...
Chapter
Some regulatory test guidelines call for the determination of an NOEC for one or more quantal responses, and it is important to understand the statistical models that are available for this purpose. This chapter will address tests that address that need. It is important to keep in mind the distinction between quantal and count data, since different...
Chapter
Continuous, quantal, and count data capture most responses that arise in ecotoxicity studies for regulatory risk assessment. There are nuances within these categories that occupy other chapters, such as time‐to‐event and mesocosm studies. The present chapter considers a different category of responses that are increasingly important, especially in...
Chapter
The primary task of risk assessors is to assess the potential for harm to the environment as a whole. One approach to this overall assessment comes from assembling the species data in a way to reflect a broader ecosystem. There are several parts to this assembly. First, a single value is required for each species and study. This could be the lowest...
Chapter
This chapter covers some important topics that do not fit easily in previous chapters because of complexities in the experimental design or method of analysis. It begins with a discussion of mesocosm and microcosm studies, a class of large, expensive studies that are sometimes considered the gold standard of ecotoxicity studies. As will be describe...
Chapter
Count data arises in many ecotoxicity studies and is distinguished from quantal in that for each subject, the count is not just zero or one but can be any nonnegative integer. Example count variables include the number of eggs produced by a frog or daphnid, the number of flowers or stems per plant, the number of micronucleated polychromatic erythro...
Chapter
This appendix develops some basic mathematic and statistical concepts that underlie the tests and models used in the book, but whose inclusion in the main text would disrupt the flow of ideas and will not be of interest to some readers. The topics include basic probability concepts, distribution functions, definition and illustrations of the method...
Chapter
This chapter introduces some basic concepts that apply to all chapters. A hierarchy of statistical models is provided that, in broad terms, defines the statistics used in this field of study and, specifically, in this text. These models range from conceptually very simple pairwise comparisons of treatment groups to a control, through trend tests ba...
Chapter
This chapter introduces some basic concepts that apply to all chapters. It begins with a discussion of the nature of toxicology or ecotoxicology studies, especially in the context of regulatory risk assessment, that distinguish them from experiments more generally. Some basic experimental design issues are discussed, such as types of control groups...
Article
Nitrate has the potential to affect steroid production. Nitrate concentrations in streams in agricultural areas may exceed concentrations showing effects in laboratory studies. The effects of nitrate and/or nitrite on endocrine relevant endpoints were tested in zebrafish and brown trout. Zebrafish were exposed in two experiments to nitrate (8.8 to...
Article
Trenbolone acetate is widely‐used in some parts of the world for its desirable anabolic effects on livestock. Several metabolites of the acetate, including 17β‐trenbolone (βTRB), have been detected in at low ng/L concentrations in surface waters associated with animal feedlots. The βTRB isomer can affect androgen receptor (AR) signaling pathways in...
Chapter
Ship’s ballast water has been a vector for the spreading of nonindigenous invasive species (NIS) around the globe for more than a century and has had devastating impact on aquatic ecosystems in many regions. Due to the harsh climate, shipping activities in Arctic waters have been limited compared to many parts of the world but will increase in the...
Article
Mild analgesics such as acetylsalicylic acid (ASA) and acetaminophen (APAP) exert their pain-relieving effect in humans by inhibition of prostaglandin synthesis. Prostaglandins play key roles in developmental and reproductive processes in vertebrates, and in recent years, it has been suggested that weak analgesics might also act as endocrine disrup...
Article
Feminization of male and juvenile fish caused by exposure to estrogens or estrogenic chemicals in effluents from central wastewater treatment plants (WWTP) is a worldwide issue of concern. Intersex and induction of the female yolk protein, vitellogenin, in male and juvenile fish are robust biomarkers for estrogenic exposure, and feminized fish have...
Article
Full-text available
The Organisation for Economic Cooperation and Development (OECD) provides several standard test methods for the environmental hazard assessment of chemicals, mainly based on primary producers, arthropods, and fish. In April 2016, two new test guidelines with two mollusc species representing different reproductive strategies were approved by OECD me...
Article
Mollusks are known to be uniquely sensitive to a number of reproductive toxicants including some vertebrate endocrine disrupting chemicals. However, they have widely been ignored in environmental risk assessment procedures for chemicals. This study describes the validation of the Potamopyrgus antipodarum reproduction test within the OECD Conceptual...
Data
S6 — Case Study Summary Vinclozolin S6 — Vinclozolin — Table S6–5
Data
S5 — Case Study Summary Trenbolone S5 — Trenbolone Table S5–5 S5 — Trenbolone Table S5–6
Data
S4 — Case Study Summary Propiconazole S4 — Case Study Summary TBT S4 — TBT Table S4–1 S4 — TBT Table S4–2 S4 — TBT Table S4–3
Data
S1 — Case Study Summary EE2 S1 — EE2 Tables S1–7
Article
Full-text available
A SETAC Pellston Workshop(®) "Environmental Hazard and Risk Assessment Approaches for Endocrine-Active Substances (EHRA)" was held in February 2016 in Pensacola, Florida, USA. The primary objective of the workshop was to provide advice, based on current scientific understanding, to regulators and policy makers; the aim being to make considered, inf...
Article
Full-text available
In this paper existing regulatory frameworks and test systems for assessing potential endocrine-active chemicals are described, and associated challenges discussed, along with proposed approaches to address these challenges. Regulatory frameworks vary somewhat across geographies, but all basically evaluate whether a chemical possesses endocrine act...
Article
This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Sur...
Article
Environmental estrogens and androgens can be present simultaneously in aquatic environments and thereby interact to disturb multiple physiological systems in organisms. Studies on interaction effects in fish of androgenic and estrogenic chemicals are limited. Therefore, the aim of the present study was to evaluate feminization and masculinization e...
Article
The chemical UV filter benzophenone-3 (BP-3) is suspected to be an endocrine disruptor based on results from in vitro and in vivo testing. However, studies including endpoints of endocrine adversity are lacking. The present study investigated the potential endocrine disrupting effects of BP-3 in zebrafish (Danio rerio) in the Fish Sexual Developmen...
Article
The aim of the present study was to investigate the effects of the androgenic endocrine disruptor 17β-trenbolone on the sexual development of zebrafish (Danio rerio) with special emphasis on the question whether adverse outcomes of developmental exposure are reversible or persistent. An exposure scenario including a recovery phase was chosen to ass...
Article
Altered concentration of the vertebrate yolk protein precursor vitellogenin is a recognized biomarker for endocrine disruption in fish, and within recent years yolk protein alteration has also been associated with endocrine disruption in bivalves. Species-specific, direct and sensitive methods for quantification of vitellogenin in fish have been av...
Article
Unlabelled: Isoflavones with estrogenic activity produced in Fabaceae plants are known to leach from agricultural areas to freshwater systems, but the effect of waterborne isoflavones in fish has not been thoroughly characterized. Therefore, the estrogenic effect of waterborne biochanin A was investigated in zebrafish (Danio rerio) and juvenile br...
Article
In July 2011, the Fish Sexual Development Test (FSDT) has officially been adopted as OECD test guideline 234 for the detection of endocrine disrupting chemicals (EDCs). Sex ratio and vitellogenin (VTG) induction are the mandatory endocrine endpoints within this test, whereas gonad staging is only included as an option. In the present study, five FS...
Article
Previous in vitro studies have reported the potential of perfluorooctane sulfonate (PFOS) to increase the toxicity of other compounds. Given the complex nature of mixtures of environmental pollutants in aquatic systems together with the persistent and bioaccumulative properties of PFOS, this study aimed at evaluating the long-term effects and toxic...
Article
Results are presented from a validation (with 5 laboratories) of the Fish Sexual Development Test (FSDT) developed to detect endocrine disrupters (EDs) and included in the OECD (Organisation for Economic Co-operation and Development) working program. The aromatase-inhibiting fungicide prochloraz was tested in zebrafish (Danio rerio) and fathead min...
Article
In streams, chemicals such as 17β-estradiol (E2) are likely to occur in pulses. We investigated uptake and biomarker responses in juvenile brown trout (Salmo trutta) of 3- or 6-h pulses of concentrations up to 370 ng E2 L(-1). Uptake by the fish was estimated from disappearance of E2 from tank water. A single 6-h pulse of 370 ng E2 L(-1) increased...
Technical Report
Full-text available
No. 150 JT03325479 Complete document available on OLIS in its original format This document and any map included herein are without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries and to the name of any territory, city or area.
Article
The bromophenol 2,4,6-tribromophenol (TBP) is widely used as an industrial chemical, formed by degradation of tetrabromobisphenol-A, and it occurs naturally in marine organisms. Concentrations of TBP in fish have been related to intake via feed, but little is known about effects on fish health after oral exposure. In this study, we exposed adult ma...
Article
Feminization of fish caused by certain estrogenic compounds e.g. 17 alpha-ethinylestradiol (EE2) has been shown to be partly reversible. So far it has not been studied if this applies for androgenic compounds too. The androgenic steroid trenbolone acetate (TbA) is used as growth promoter in beef cattle in the United States, South America, and Austr...
Article
The main effluent from oil and gas production is produced water (PW), a waste that contains low to moderate concentrations of oil-derived substances such as polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs). PW components may be present in seawater at low concentrations over large areas in the vicinity of oil and gas production facilit...
Article
The sensitivity of juvenile brown trout towards estrogenic chemicals (17beta-estradiol [E2], estrone [E1], 17alpha-ethinylestradiol [EE2], 4-tert-octylphenol [OP], and n-butylparaben [BP]) was tested in laboratory experiments with plasma and liver vitellogenin concentrations as endpoints. Vitellogenin concentrations were also assessed in juvenile b...
Article
Some chemicals have the potential to adversely affect sexual development through multiple endocrine actions. Prochloraz is an imidazole fungicide that displays diverse mechanisms of action, including inhibition of aromatase activity, inhibition of androgen synthesis, and antagonism of the androgen receptor. The objective of this study was to assess...
Article
Full-text available
Juvenile zebrafish (Danio rerio) were exposed to different dilutions (0, 0.67, 2.5, 10, and 50%) of effluent water from a Swedish pulp mill that previously has been reported to be androgenic to fish. Exposure was performed between days 10-38 days post-hatch. Fish were sampled for whole-body vitellogenin concentrations at day 38 post-hatch and for h...
Article
Managed by the Organisation for Economic Co-operation and Development (OECD), a comprehensive work is carried out in numerous laboratories to develop test guidelines for the detection of endocrine disrupting chemicals in humans, and various animal species. Development of tests to detect chemicals with endocrine disrupting properties in fish is a pa...
Article
In the present study, the effects of the anti-estrogen ZM 189,156 and the aromatase inhibitor fadrozole were evaluated in a 40-day juvenile assay developed for screening of endocrine disrupting chemicals. Juvenile zebrafish were exposed from 20 to 60days post hatch (dph) to ZM 189, 154 (100μgl−1 and 200μgl−1) and fadrozole (10, 32, and 100μgl−1). V...
Article
In a partial life-cycle test, the impact of 17alpha-ethinylestradiol (EE2) and 17alpha-methyltestosterone (MT) on juvenile zebrafish was evaluated by use of vitellogenin measurements and gonadal development. Exposure to EE2 (1-25 ng/l) resulted in a dose-dependent increase in vitellogenin production starting at 2 ng/l. Significant changes in sex ra...
Article
Several histological methods were tested for their potential to detect the in vivo induction of vitellogenin in zebrafish, after exposure to 17beta-oestradiol (E2), and validated by correlating semi-quantitative measurements on digital images to vitellogenin plasma values measured by ELISA and morphological criteria. All methods, except for vitello...