E1vir111eP11o1U1u liCoonu rse Evan C. Birchard ENVIRONMENTAL PROTECTION DEPARTMENT IMPERIAL OIL LIMITED foLpub-'3e--4 ENVIRONMENTAL POLLUTION COURSE Evan C. Birchard Environmental Protection Department Imperial Oil Limited - i - "The greatest problem facing man today is the ecological one of harmonious adjustment to the ecosystem of which he is a part~" - ii - CONTENTS PAGE PREFACE iv INTRODUCTION 1 UNPOLLUTED ENVIRONMENT Terminology 2 Individual Concept 3 Population Concept 3 Community Concept 13 Ecosystem Concept 18 Ecological Cycle of the Ocean 25 Eutrophication 28 Summary to Unpolluted Environment 30 POLLUTED ENVIRONMENT Terminology 34 Tolerability 35 Individual - Lethal & Sublethal 37 Population 44 Community 46 Ecosystem 47 Movement of a Pollutant Through the Ecological Cycle of the Ocean 50 Cultural Eutrophication 53 Lake Erie 54 Summary to Polluted Environment 57 - iv - PREFACE There is today a great deal of concern about the deterioration of our environment. In some cases the concern is genuine, at other times it is exaggerated or untrue. In order to separate fact from fiction,it is necessary to first have a broad understanding of the principles and processes operating in an environment. The "Environmental Pollution Course" presented on the following pages, was originally prepared for, and presented to Imperial Oil personnel across Canada, to add to their under standing of the environment and the effects of pollution on the environment. Because of the general nature of the course, and its wide field of coverage, it was not possible to deal extensively and in great detail with specific topics. Rather, it was the intent to merely touch the surface of the subject content, and draw its outline, with the hope of providing an overall picture. The course content tends to be geared heavily to the water environment. But although the examples are predominantly oriented towards water, the underlying principles themselves apply generally to any type of environment - aquatic or terrestrial. Environmental Protection Department Imperial Oil Limited 111 St. Clair Ave. West Toronto 195, Canada - 1 - INTRODUCTION Pollution may be operationally defined in terms of its effects on living organisms. In this sense the assessment of pollution should be primarily a biological one. Most studies of pollution however, have been oriented toward chemical and physical standards, with the biological aspects either omitted or in low priority. There are a number of reasons for this exclusion of biological data when assessing the effects of pollution. To begin with, chemical and physical data can usually be transformed into numerical expressions that are easy to use and express . Secondly, the collection of biological data is often considere d time consuming, expensive, and difficult to expr ess in a meaningf ul manner. Thirdly, there is often a lack of basic biological bac k ground exp eri ence among t he very peopl e concern ed with pollution. This is unfortunat e, for attempting to deal with a specific enviro nmental pollution problem without fully understanding the underlying biological principles that operate in an unpolluted and polluted environment can often lead to misinterpretation, oversimplification, or gross error. The content of "Environmental Pollution Course" is set up so that, in the first section, we may become familiar with the biological principles operating in a natural, unpolluted environment, including the individual, population, community, and ecosystem concepts. This is designed to provide a baseline from which we can then proceed to the second section on a polluted environment, and see the effects of pollution on these four levels of integration. The third section deals with biological informati on systems, and their importance as a source of biological dat a for assess ing the effects of pollution. The fourth concluding section dea l s br ie fly with man and his environment. - 2 - UNPOLLUTED ENVIRONMENT TERMINOLOGY The relationship of a plant or animal to its surroundings is termed an ecological relationship, or more commonly the ecology of the organism. The phrase "ecology being damaged" does not refer to a physical destruction, but rather to the breakdown of relationships between various components of the environment. All ecological relationships take place in a physical-chemical setting, i.e. a non-living or abiotic setting. Abiotic elements include the basic inorganic materials such as water, carbon dioxide, oxygen, etc. and physical factors such as moisture, wind, currents, temperature, light, etc. Within this abiotic setting there exists the plants, animals and microbes, that is the biotic components of the environment. The biotic components interact with one another and with the abiotic components in a fundamentally energy-dependent fashion. The abiotic and biotic elements together comprise an ecological system, or an ecosystem. An ecosystem is a community of organisms interacting with one another plus all the external influences around them with which they live and also interact. These influences on an ecosystem are collectively called the environment. Used in its proper context, an environment is all the external influences and conditions that affect the life and development of an organism. The concept of an ecosystem is an abstraction. It is abstract in the sense of being a conceptual scheme developed from a knowledge of real systems.Yet in spite of the great diversity in types - 3 - of ecosystems - from small to large, terrestrial to aquatic, laboratory to field, and in spite of the unique combinations of particular abiotic and biotic components in any one ecosystem, there are certain general structural and functional attributes that are recognizable. The first of these structural attributes is the individual. INDIVIDUAL CONCEPT An individual, during its life time, has but one ultimate role - that of producing offspring. An individual is constantly subjected to stress and adversity from its environment that could result in death or a loss of reproductive capabilities. As such, one individual by itself is not an important factor in the over-all ecological system. It is a frail, vulnerable, and highly unstable entity. To overcome these limitations individuals tend to form groups, which are in turn combined with other groups of organisms, to form a particular community. When a group of similar individuals occur in close proximity to each other, they are referred to as a population. POPULATION CONCEPT A population is a group of potentially breeding individuals at a given locality. Each individual is a member of a natural population that is reproductively isolated from other populations of different types of individuals. There are two opposing forces operating in the growth and development of a population: one of these is inherent, and characteristic of each species - the ability to reproduce at a given rate; opposing this is an inherent capacity for death. This opposition co~es from all the forces of the physical, chemical and biological environment - 4 - in which an individual exists. These two opposing forces are called respectively, biotic potential, and environmental resistenc e. It is the role of the population to ensure that environmental resistence never exceeds a species biotic potential. Populations typically follow a growth pattern that is sigmoidal in shape, (Fig. 1). The initial growth period is slow. This is followed by a period of rapid increase, and then finally a slowing down. When the growth rate levels off, and there is no net change in population, it has reached an equilibrium with the surrounding environment. That is, it has reached the limit at which the environment can support the population, a limit referred to as the carrying capacity of the environment. If some factor of the environment is shifted, a different equilibrium level may result, so that 'carrying capacity', like most other ecological concepts, is subject to change. Once a population reaches its carrying capacity a number of possibilities exist, (Fig. 2): 1. the population will maintain itself at the same level for an infinite length of time. 2. the population will decline and may eventually succumb to extinction. 3. the population will fluctuate either regularly or irregularly. The first type, in which a population maintains itself for a infinite length of time, is rare. It will occur only where the supply of food is unlimited, where harmful biproducts are continuously removed, and where all other environmental factors remain unaltered. -5- FIGUREI POPULATIOINN GROWTHP ATTERN CARRYING CAPACITY GROWTCHU RVE(N ) t NUMBER(NS) TIME (t) CARRYINCGA PACIT-YT HATP OINTIN THEG ROWTCHU RVEIN WHICHT HE POPULATIOISN AT EQUILIBRIUMW ITH THE ENVIRONMENRTE,S ULTINIGN NON ET CHANGEIN POPULATIONN UMBERS.