Ecotoxicology

Question 1

What are the main courses of environmental chemical pollution?

Answer 1

Industrial, urban ,and agricultural activities are the main causes

Question 2

What is the proof that chemical substances are growing exponentially

Answer 2

CAS in the last 10 years has added 75 million entries into its data base. This triple the number of entries than it in the first 40years

Question 3

Today how many chemicals are known to humanity ?

Answer 3

150,000,000

Question 4

How many groups can anthropogenic activities and chemical pollution be grouped into ? Name the four with an example each .

Answer 4

Group 1: lubricants, additives,solvents and flame retardants (l.A.S.F) eg pcb
Group 2: metals and organic booster biocides (M.O.B.B)eg copper
Group 3 : pharmaceuticals,personal care products,detergent,hormones. (PPDH) eg. Erythromycin.
Group 4:pesticides such fungicides , insecticides and herbicides eg. Diuron

Question 5

What is toxicology?

Answer 5

The study of the adverse effects of chemicals on living organisms ( human and non-human organisms)

Question 6

What is truhaut’s definition of eco toxicology ?

Answer 6

It’s is a branch of toxicology that aims to understand the toxic effects of natural or synthetic pollutants , to an ecosystem , animals(including humans) vegetation and microbial in an integral way.

Question 7

What is Levin’s definition of eco toxicology?

Answer 7

It is the science that seeks to predict the effects of chemical substance on ecosystems

Question 8

What is the tsk of eco toxicology

Answer 8

It is to assess, monitor and predict the fate and effect of foreign substances in the environment.

Question 9

What is eco toxicological data used for?

Answer 9

It is used for chemical risk assessment in the env.

Question 10

What are the three different aims of ecotoxocological research?

Answer 10

1. For scientific purposes: ect research helps scientists better understand the fundamentals of the interactions between chemicals and biological systems.
2. For technological purposes: for the development of models of distribution, fate and effects of chemicals in a biosphere.
3. For environmental regulation purposes: ect research serves as a scientific basis for the development of environmental quality standards that ensure ecosystem services, sustainable development and ecosystem health.

Question 11

Why do we need eco toxicology?

Answer 11

1. We need to know how and where chemicals are used (source)
2. The environmental fate (concentration of chemicals) how they spread , how long do they stay after spreading .
3. The potential disturbances (effects)

Question 12

How many pollutant’s are regulated in surface waters in Europe? How many priority pollutants are in the EU framework?

Answer 12

Pollutants found in surface waters in EU : 10^8 chemicals are found in CAs . 10^5 chemicals are used daily . 10^4 chemicals are found in environmental samples.

The EU water frame work directive has 45 priority pollutants it initially started with 24.

Question 13

In chemical risk assessment and ecological risk assessment there are two. Aim assessment methods what are they?

Answer 13

1. Prospective assessment : this usually involves the development of regulations such as the biocide product regulations ,REACH , and the Pesticide regulations.
2. Restrospective assessment: this usually involves the scientific community, here scientists go out to collecte date on. The various types and concentration of chemicals in the environment. This has led to the development of water framework directive and marine strategy framework directive.

Question 14

There are two main types of complexities in eco toxicology, what are they?

Answer 14

1. Chemical complexities
2. Biological complexities

Question 15

Name and define each factor to consider under chemical complexities

Answer 15

Dissemination and transformation: refers to how a substance spreads in an ecosystem.
Persistence: refers to how long a substance stays in an ecosystem.
Bioavailability: this refers to how much of a substance can be absorbed by and organism and how much effect the substance can have within the organism . Ie. It’s ability to reach its site of action or target .
Bioaccumulating: this is when concentration of a substance in an organism increases . This occurs when uptake + absorption > degradation + excretion.
Biomagnification : this is when bio accumulation is taken to the food web. This occurs when contraction of a substance increases as you go higher in a food chain mainly due to diet.

Question 16

How do persistent organic pollutants( P.OP )work ?

Answer 16

When the substance is spilled they are very persistent and do not degrade easily. They accumulate in fatty tissues of organisms , they biomagnify . Because they move up the food chain in higher concentrations ( biomagnify) they have a wide geographical spread and are very toxic.

Question 17

Biological complexities; what are some of the factors to consider here ?

Answer 17

Is the risk acute or chronic?
What is the severity of the effect.
What is the time over which it occurs
Does it affect just one species or several others ?

Question 18

Acute or chronic risks explain

Answer 18

So these vary based on the organism . Should a chemical that lasts 5hours affect a fish that reproduces every couple of days then here the risk is acute because it does not move into or affect reproduction . However should a chemical that lasts 24 hours affect a fish that reproduces every two hours then the risk is chronic because it moves into or affects reproduction.

Question 19

Mode of action , what is it ?and what are some of the targets for toxic substances

Answer 19

Mode of action usually refers to the first organ or thing with a living organism that the chemical substance interacts with first . It is usually where the first of the substance are seen.

Targets for toxic substance:
Organelles
Tissues
Nucleic acids
Membranes
Enzymes
Cells

Question 20

Give some examples of effects (endpoints)

Answer 20

Photosynthesis
Reproduction
Mobility
Mortality
Growth
Specific effects that address mode of action of the substance

Question 21

Draw the diagram depicting the relationship between the effects of toxic substances and time

Answer 21

Few seconds to minutes: binding of contaminants to receptors
Minutes to days : biochemical response
Days to weeks : physiological effects or alteration
Weeks to months : effects on individuals
Months to years: effects on population and communities

Question 22

Under concentration - response analysis what is the meaning No Observed Effect Concentration (NOEC) , Low Observed Concentration effect (LOEC) and EC50 ( effect concentration), LC50 ( lethal concentration 50)

Answer 22

Ec50 : this refers to the concentration of a substance where 50%of the test population is affected.
LOEC : this refers to the concentration of a substance where 30% of the test population is affected.or the lowest concentration that affects test organisms
NOEC : this is the concentration level where there is no observed difference between test population and control.
LC50: this is the concentration where half of the population is killed .

Question 23

What are the three experimental systems in aquatic eco toxicology?

Answer 23

Laboratory bioassays
Field studies
Micro and mesocosms

Question 24

Define the following:
Bioassays in vitro and in Vivo
Bio markers
Ecological methods

Answer 24

Bioassays : this is an analytical method used to determine the concentration or potency of a substance by its effect on living animals or plants (in Vivo ) or cells and tissues (in vitro).usually under defined lab conditions.
Bio markers : these are biochemical, physiological, cellular and behavioural variations that often provide evidence of exposure to and or effects of one or more chemical pollutants. Usually measures the biological responses of field exposed organisms.
Ecological methods: this refers to studying of measuring changes that occur at higher biological organisations I.e populations and communities.