: Microplastics in Freshwater Systems: A Review on Its Accumulation and Effects on Fishes

Asif Raza

CONTENTS

  • 12.1 Introduction 205
  • 12.2 Microplastics Overview: Types and Sources 206
  • 12.3 Microplastics 207
  • 12.4 Methods of Ingestion of MPs by Fishes 208
  • 12.4.1 Data Analysis 208
  • 12.5 Effects of Microplastics on Fishes 210
  • 12.6 Recent Global Actions on MPs 211
  • 12.7 Conclusions 213

References 213

Introduction

Plastic materials are of vital use, being noncorrosive, durable, nonreactive, lightweight and easy to handle, and its cheap manufacturing cost has made it a material of choice. Plastic production continues to accelerate and the reason behind this is the adoption of a use-and-dispose culture by almost all the developed and developing countries. Annual plastic production has increased from 1.5 million tonnes in the 1950s to 288 million tonnes in 2012 [1], with only 9% of plastics being currently recycled in the US [2]. The nonrecycled plastic is being disposed of in dump yards; a major proportion of it is thrown as debris into water bodies, including oceans and rivers. It is estimated that 275 million metric tonnes of plastic waste is being generated each year (based on reports from 192 coastal countries in the year 2010). Due to a variety of physical, chemical and biological factors, these nonrecycled plastics in the water bodies break down to form microplastics (MPs). MPs from personal-care products are one of the potential sources of direct addition to freshwater streams. Most of the studies have occurred in marine water systems, but little data are available on the abundance and distribution of MPs in freshwater systems;

* Previously published as Open Access article in Preprints 2018, 2018100696 (doi: 10.20944/ preprints201810.0696.vl).

however, MP pollution is found in estuarine water and freshwater systems [3,4]. Most studied impacts of plastic debris on biota are their physical effects such as entanglement, ingestion and suffocation/asphvxia [5-7]. These microplastics are often consumed by fishes via a variety of methods and cause adverse effects leading to mortality, neurotoxicity, cytotoxicity, liver stress, behavioral changes, oxidative stress, genotoxicity, etc. [80]. Plastic abundance was found within the stomach, gut and intestines of the fishes. The objective of this chapter is to review the current knowledge of MP contamination in freshwater and its effects on fishes. A summary of its occurrence and distribution is also discussed, along with explored knowledge of its effects on fish health have been presented in this study. Several challenges have been discussed, and suggestions are provided for further research work.

 
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