Posted: June 9th, 2015

BIOL 433 Toxicology and Monitoring Laboratory /Title of the Lab: Ecological Risk Assessment

BIOL 433 Toxicology and Monitoring Laboratory /Title of the Lab: Ecological Risk Assessment

________________________________________THE GENERAL PURPOSE OF THE LAB
•    Perform an ecological risk assessment on three species in the Qatari environment
•    Find the LC50, NOAEL and LOAEL on the three species caused by the stressor (Chlorine)
BACKGROUND ON THE TOPIC
Ecological risk assessment is a study done to evaluate an environment considering the factors that this environment are exposed to, at what levels and concentrations, and what are the effects of these factors (stressors) on the ecosystem. This process can be done from the range of evaluating individuals in the ecosystem up to evaluating the whole ecosystem. ERA is an important assessment to be done considering the fast industrialization, urbanization and many other processes going on that include the usage and disposal of various stressors to the environment. Qatar’s industries have been disposing some chemicals into the environment in very large numbers. Chlorine is a very toxic element which is being used in industries (i.e. Chlorinated water is used to cool off machines in oil rigs and prevents clogging caused by marine organisms; later on it is disposed in the sea), this is why this ERA is focusing on Qatari environment is very fragile and susceptible, it’s marine ecosystem is facing many challenges. AlKhor area was chosen because it is very close to the industries, which dispose chlorine into the seawater. Three species were chosen because they are the most commonly abundant, sensitive and can be used as bio-indicators. Other physical factors were controlled to be able to study the effect of the stressor only on the species with no interference of other factors. [1]
MATERIALS:
•    Glass Aquarium
•    Pipets
•    Seawater
•    Fish
•    Shrimp
•    Hermit crab
•    Oxygen pump: to provide the species with oxygen
•    Thermometer: to measure temperature
•    pH meter: to measure pH
•    Refractometer: to measure salinity
•    Conductivity meter (EC) to measure conductivity
•    Chlorine in concentrations of  (0, 0.025, 0.05, 0.1, 0.2, 0.4)
METHODS: [2]
1- Filling aquariums with the volumes according to the table from the previous report
2- Placed 10 individuals of each species in each aquarium (species separated from each other)
3- In the large two glass aquarium (Control: 0micro liters of Hypochlorite, Test: Containing 400 micro liters of hypochlorite), place 20 individuals of each species all together which will be relevant to marine ecosystem (microcosm).
4- Oxygen pump is set to the aquariums to provide dissolved O2
5-Measuring different parameters of water (Temp, salinity, conductivity, pH) at time= 0, 24hr, 48hr, 72hr, 96hr.
6- Calculate mortality percentage by: %Mortality= (# of death \ Total number of sample) x 100
7- Adjust the mortality rates
7- Drawing a graph and finding LC50, NOEL and LOEL.
RESULTS:
Mortality rates have been adjusted using the formula Adj%=((Mortality% in treated plot + Change % in control plot population)/100+ Change % in control plot population)) x100
Control plots mortality rate were adjusted to Zero, and other mortality rates were adjusted accordingly.
Sample calculation; (Adjusting mortality rate of Shrimps in concentration 0.025)
=  [(40%+ 70%)/ (100+70%)]x100
=64.7%
Plots that needed adjustment got adjusted accordingly.

Table1: Mortality of fish                Table2:Mortality of shrimp    Table3:Mortality of Hermit crab

Graph1:  Graph illustrating the mortality of fish
LC50= Anti-log (-1.8) = 0.015 mg/L of Chlorine causes 50% of population to die.
NOAEL=Anti-log(-2)= 0.01 mg/L there were no observed adverse effects
LOAEL= Anti-log (-2) = 0.01mg/L is the concentration with the lowest observed effects

Graph2: Graph illustrating the mortality of shrimps
LC50= Anti-log(-0.01) = 0.9mg/L will cause 50% of shrimps population to die
NOAEL=0.025 mg/L there were no observed adverse effects
LOAEL= Anti-log(-1.5)= 0.03mg/L is the concentration with the lowest observed effects

Graph3: Graph illustrating the mortality of hermit crabs.
LC50=Anti-log (-1) = 0.1mg/L causes 50% of hermit crab population to die.
NOAEL=Anti-log(-2) = at 0.01mg/L there were no observed adverse effects
LOAEL=Anti-log(-1.6)= 0.02mg/L is the concentration with the lowest observed effects
Calculating Hazard Quotient= (Expected environmental concentration / L50)
HQ>1 potential of high risk, HQ<1 low risk, HQ ~ 1 potential risk
EEC= 0.03mg/L
Fish= (0.03/0.015) = 2
Shrimp=(0.03/0.9) = 0.033
Hermit Crab=(0.03/0.1) = 0.3
DISCUSSION AND CONCLUSIONS
Chlorine is a toxic compound at very low levels, as obtained from the graphs above the LC50 to each of the species are very low concentration. Hazard Quotient is in indicator of the risk caused by the Chlorine concentrations, in which fish shows very high sensitivity to discharged chlorine and posses a hazard quotient of 2, which is very high and indicates a potential of very high risk this is where certain measures needs to be taken to reduce the amounts of chlorine discharged in the sea. Shrimp and hermit crab shows hazard quotients of less than 1, which show very low risk and are less sensitive to the amounts of chlorine discharged in seawater. An ecological risk assessment is a very important process that needs to be done in areas with affected environments due to disposal of certain chemical, in order to evaluate the environment and take action in reducing the risk and setting rules and regulations that will help minimize the load on the environment.
The obtained data cannot be considered to take action due to several errors and issues;
1-No replicates were done, and the sample number we have is too small to represent a population or an ecosystem.
2- High mortality rates in the control sample, this is not supposed to happen.
3-High mortalities might have been affected by other factors like environmental shock and transportation stress.
Most importantly is understanding the concept of ERA and how is it supposed to be performed, in which this goal was accomplished.
REFERENCES
[1]Ecological Risk Assessment. (n.d.). Retrieved June 6, 2015, from http://www.environment.gov.au/science/supervising-scientist/research/ecological-risk
[2]Lab report

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