Biology studentYeah it bioaccumulates in organisms once consumed and makes it way up the food chain causing harm. Etc
Biology studentYeah it bioaccumulates in organisms once consumed and makes it way up the food chain causing harm. Etc
IndeedBiology student
State rankfasabualsaisabuld
you seem so prepared for chemistry good job man haha
haha yeah my plans where to finish revision for all subjects this week, leaving me two weeks of nothing but papers and essays.fasabualsaisabuld
you seem so prepared for chemistry good job man haha
naooo the QZP guy will.State rank
I'll answer my own question since no one else is bothering #sadlyfnaooo the QZP guy will.
Next question:
Describe the process of eutrophication, and assess the suitability of water quality tests used to monitor it.
Dislike this question hahaAnother Question:
HSC online says DO is a valid measurement, so does my tutor and teacher at school.I don't think DO/BOD is a valid measurement of eutrophication because it is affected by too many variables other than phosphorous/nitrogen content i.e. algae activity. Do you have a source?? I havn't been doing any chem lately so I might be wrong :X
Organic wastes from sewerage, agricultural run off, etc. also cause low DO and high BOD. Also, photosynthesis from aquatic plants affects DO.HSC online says DO is a valid measurement, so does my tutor and teacher at school.
http://hsc.csu.edu.au/chemistry/core/monitoring/chem945/945net.html#net1
Were you expecting measuring the concentration of nitrogen and phosphorus and if they N is greater than 10:1 it is safe and if not then eutrophication can or is occuring.
Bold part - algae activity indicates that eutrophication is occuring? It is because of excess nitrogen and phosphorus that results in algal blooms which causes DO levels to decrease and BOD levels to increase. Why isn't that a valid measurement?
Yes i agree that organic wastes etc cause low DO levels and high BOD. However, if eutrophication was to occur, photosynthesis would not occur in aqautic plants as algae remain at the surface of the water and block sunlight from entering the water. IF somehow they are able to undergo photosynthesis, it would not make a significant change in DO levels as algae and the plants undergo respiration at night, decreasing DO levels dramatically. Algae also reproduce exponentially and really quickly therefore will be lots and lots of algae present.Organic wastes from sewerage, agricultural run off, etc. also cause low DO and high BOD. Also, photosynthesis from aquatic plants affects DO.
Example scenario: TDS and turbidity of waterway is affected such that photosynthesis activity of aquatic plants is reduced. This leads to a decrease in DO. It would be incorrect to conclude that this was caused by eutrophication.
I just don't see how you can pin-point low DO and high BOD to eutrophication. :S Jacaranda has nothing about measuring eutrophication with DO/BOD but instead titration and colourimetry.
BOLD: Yes I've been saying that considering other factors, then measurement of DO/BOD is not valid for purposes of monitoring eutrophication (which is the Q).Yes i agree that organic wastes etc cause low DO levels and high BOD. However, if eutrophication was to occur, photosynthesis would not occur in aqautic plants as algae remain at the surface of the water and block sunlight from entering the water. IF somehow they are able to undergo photosynthesis, it would not make a significant change in DO levels as algae and the plants undergo respiration at night, decreasing DO levels dramatically. Algae also reproduce exponentially and really quickly therefore will be lots and lots of algae present.
Bold part - Reduced photosynthesis is yes because of the water being turbid and it is turbid because of eutrophication. It's because of the algae that the water is turbid. Algae settles on the surface of water and acts as a barrier, preventing light from entering.
If you were to bring in other factors, then all tests are not suitable except for directly measuring nitrogen and phosphorus levels. And if the nitrogen to phosphorus ratio is greater than 10:1, then it is safe.
The italicised part would then be the ONLY suitable way of testing for eutrophication.
So colorimetric testing it is!BOLD: Yes I've been saying that considering other factors, then measurement of DO/BOD is not valid for purposes of monitoring eutrophication (which is the Q).
Correct me if I'm wrong, but your method (measuring significant low DO and high BOD) only indicates algal blooms. How is that monitoring eutrophication? If you instead measure minimal low DO and high BOD then this is unreliable to monitor eutrophication progress due to the external factors as I have mentioned that may affect DO and BOD. (What I'm trying to show is that both significant/low changes in DO/BOD are not very good for monitoring eutrophication which is what you were trying to talk about or something)
Usually we monitor something so we can prevent problems. By direct measurements of nitrogen/phosphate content using e.g. colourimetry we can measure their exact concentrations and thus the extent of eutrophication.
Btw I did a quick check on conq. chem also and they say the same thing as jacaranda (there is no mention of using measurements of DO and BOD for monitoring eutrophication)
Indeed we did and true!Discussion is always good I wouldn't discount measuring DO/BOD entirely. I think it is often a "good" but not best measurement of eutrophication which is why you may see it as the answer in MCQ for measuring eutrophication. But in long responses, go with colourimetric analysis for reasons above (it is more reliable and direct). NICE! We cleared stuff up
It is 16:1 ratio of N (Pretty important to not get this wrong as my tutor who is a hsc marker and she take away marks for people not giving the correct details... SO watchout!!)HSC online says DO is a valid measurement, so does my tutor and teacher at school.
http://hsc.csu.edu.au/chemistry/core/monitoring/chem945/945net.html#net1
Were you expecting measuring the concentration of nitrogen and phosphorus and if they N is greater than 10:1 it is safe and if not then eutrophication can or is occuring.
Bold part - algae activity indicates that eutrophication is occuring? It is because of excess nitrogen and phosphorus that results in algal blooms which causes DO levels to decrease and BOD levels to increase. Why isn't that a valid measurement?
Never learnt that wtf...It is 16:1 ratio of N (Pretty important to not get this wrong as my tutor who is a hsc marker and she take away marks for people not giving the correct details... SO watchout!!)
Also you have to be familiar with the kjedahl's method of determining total nitrogen content of the sample and for total phosphorous you need to learn about colorimetry which is quite similiar to AAS tbh...
BTW she took off marks to almost everyone perhaps not the state rankers in the 2009/2010 hsc exam (i'm not sure which one) for not writing the proper definition of BOD. She said they either missed the standard conditions or that they forgot to mention that BOD is the difference in dissolved oxygen concentration.... SO BASICALLY IN CHEM, YOU ARE LOSING MARKS AND YOU DON"T REALISE IT TAKE CAUTION !!!!!
rofl mateIt is 16:1 ratio of N (Pretty important to not get this wrong as my tutor who is a hsc marker and she take away marks for people not giving the correct details... SO watchout!!)
Also you have to be familiar with the kjedahl's method of determining total nitrogen content of the sample and for total phosphorous you need to learn about colorimetry which is quite similiar to AAS tbh...
BTW she took off marks to almost everyone perhaps not the state rankers in the 2009/2010 hsc exam (i'm not sure which one) for not writing the proper definition of BOD. She said they either missed the standard conditions or that they forgot to mention that BOD is the difference in dissolved oxygen concentration.... SO BASICALLY IN CHEM, YOU ARE LOSING MARKS AND YOU DON"T REALISE IT TAKE CAUTION !!!!!