Marine Mammal Ecotoxicology

Impacts of Multiple Stressors on Population Health

Maria Cristina Fossi,Cristina Panti

• Publisher: Academic Press
• Year: 2018
• ISBN:
  9780128122501
• Topic: Biological Sciences
• Subtopic: Zoology
• Index: Biological Sciences

Marine Mammal Ecotoxicology: Impacts of Multiple Stressors on Population Health provides tactics on how to develop a comprehensive methodology for the study of existing threats to marine mammals. By presenting a conservation-biology approach and new and emerging technologies, this work helps provide crucial knowledge on the status of marine mammal populations that not only helps readers understand the ecosystem's health, but also instigate mitigation measures. This volume provides information that helps investigators unravel the relationships between exposure to environmental stressors (e.g., climate change, pollutants, marine litter, pathogens and biotoxins) and a range of endpoints in marine mammal species.

The application of robust examination procedures and biochemical, immunological, and molecular techniques, combined with pathological examination and feeding ecology, has led to the development of health assessment methods at the individual and population levels in wild marine mammals.

• Provides a comprehensive, worldwide update and state of knowledge on current research and topics on marine mammal ecotoxicology
• Includes coverage of both new and emerging technologies
• Features a multidisciplinary approach that gives readers a broad, updated overview of the threats facing marine mammals and related conservation measures

Section I

Legacy and Emerging Contaminants in Marine Mammal Populations

Outline

Chapter 1. Organochlorine Contaminants and Reproductive Implication in Cetaceans: A Case Study of the Common Dolphin

Chapter 2. Feeding Ecology Tools to Assess Contaminant Exposure in Coastal Mammals

Chapter 3. The Effects of Oil Exposure on Cetaceans

Chapter 4. Legacy Contamination in Estuarine Dolphin Species From the South American Coast

Chapter 5. Poly- and Perfluoroalkyl Substances in Marine Mammals

Chapter 6. Impacts of Marine Litter on Cetaceans: A Focus on Plastic Pollution

Chapter 7. Persistent Organic Pollutants in Cetaceans Living in a Hotspot Area: The Mediterranean Sea

Chapter 8. Pollutants in Tropical Marine Mammals of the Galápagos Islands, Ecuador: an Ecotoxicological Quest to the Last Eden

Chapter 1

Organochlorine Contaminants and Reproductive Implication in Cetaceans

A Case Study of the Common Dolphin

Sinéad Murphy^1,2, Robin J. Law^2,3, Robert Deaville², James Barnett⁴, Matthew W. Perkins², Andrew Brownlow⁵, Rod Penrose⁶, Nicholas J. Davison⁵, Jonathan L. Barber³, and Paul D. Jepson^{2 1}Galway-Mayo Institute of Technology, Galway, Ireland ²Zoological Society of London, London, United Kingdom ³Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, United Kingdom ⁴University of Exeter, Penryn, United Kingdom ⁵SRUC Veterinary Services, Inverness, United Kingdom ⁶Marine Environmental Monitoring, Cardigan, United Kingdom

Abstract

Organochlorines, such as polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), are persistent organic pollutants that both bioaccumulate and biomagnify within marine food webs. These legacy pollutants are known endocrine disruptors and have been reported to have adverse effects on endocrine, reproductive, and immune functions in humans, laboratory animals, and wildlife. This chapter will review evidence of pollutant-mediated effects on the reproductive system in cetaceans from exposure to PCBs and DDT. In addition, an assessment of reproductive failure and reproductive dysfunction was undertaken on stranded and bycaught female common dolphins from the Northeast Atlantic, and their association with exposure to PCBs was investigated. Within the sample, 16.8% (18 out of 107) of females presented with reproductive system pathologies that were associated with higher blubber ΣPCB lw concentrations, above the threshold for the onset of adverse health effects in marine mammals. Cases of reproductive failure were also reported that may be linked to exposure to these endocrine-disrupting chemicals. The continued exposure to legacy pollutants, and new emerging pollutants, raises concerns about the current and future population-level pollutant effects on Northeast Atlantic common dolphins.

Keywords

DDT; Delphinus delphis; Endocrine-disrupting chemicals; Neoplasm; PCB; Reproductive disorders; Reproductive failure

Introduction

Organochlorines (OCs) are known persistent organic pollutants (POPs) that both bioaccumulate and biomagnify within marine food webs. This chapter will focus on the legacy pollutants polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), which have been reported to have adverse effects on endocrine, reproductive, and immune functions in marine mammals (Hall et al., 2006a; Murphy et al., 2015; O’Shea et al., 1999; Reijnders et al., 1999; Vos et al., 2003). The chapter is divided into three sections, including an introduction to OCs and their effects, a review of the published cases of reproductive failure and dysfunction in cetaceans associated with exposures to OCs, and a new case study exploring the effects of PCBs on reproduction in short-beaked common dolphins (Delphinus delphis) in the Northeast Atlantic. Thus, this chapter provides a comprehensive overview of published and new information on OCs and reproductive implications in cetaceans.

PCBs were originally synthesized in the 19th century, but they came into widespread use in the 1930s. They were primarily used in mineral oils used as dielectric fluids in electrical equipment such as transformers and capacitors, but they were also used in a wide variety of other applications, including as flame retardants, in paints and lacquers, hydraulic fluids, caulks, and sealants (Diamond et al., 2010). A number of different products were produced, differing in the proportion of chlorine incorporated and the range of congeners comprising the product (e.g., Aroclor 1242, 1254 and 1260, manufactured by Monsanto: 42%–60% chlorine). Most of the PCB products were produced in the United States and Europe (Law and Jepson, 2017). In the mid-1960s, they were discovered as contaminants in fish from the River Viskan in Sweden, and later in other wildlife, highlighting their widespread environmental occurrence (Jensen, 1996; Jensen et al., 1969). Subsequently, it was discovered that PCBs are persistent and highly mobile, being transported to the Arctic by a process known as global distillation, or long-range atmospheric transport (Jepson and Law, 2016). Controls on production and use in both the United States and Europe, where over 1 million tons of PCBs were produced, began around the early 1980s.

Initially, marine environmental concentrations of PCBs declined rapidly following the ban in America and Europe in 1979 and 1985, respectively, but in some instances, this decline has stalled (Aguilar and Borrell, 2005; Borrell and Aguilar, 2007; Jepson et al., 2016; Law et al., 2012). Continued input into the marine environment through activities such as dredging of PCB-laden sediment and mariculture, as well as from land-based sources such as leakages from old landfills and ...