Hey,
First of all, I like the flow of your writing!
I wanted to comment on a few things:
- Try making your sentences less complex (i.e. break them up a bit).
- Don't quote Science Direct - quote the paper/book/other resource Science Direct is showing you
- You seek to investigate the claim that "Organic compounds are more harmful then beneficial to the environment and humans. " but your research question implies that you already know the answer
- Be careful with wording (e.g. page 5 you list the research question but refer to it as "the claim")
- Variance and variation are different terms. If unsure, the word to use is "variation"
- I'm not sure what you mean by "the exposure category boundaries were altered several times to ensure result accuracy" how did altering them ensure accuracy?
- Be careful with phrasing "it is essential to limit regulations for the permitted amount of benzene, to decrease the risk of leukemia" means that there should be less regulation, not that regulation should enforce low benzene levels.
- if a study design means you can only speak to correlation rather than causation then acknowledge that
- makes sure this sounds like your voice - would you use the term "cytogenic aberration"?
- try not to cast a value judgement that chem data is better than bio data in general. Maybe be more specific with how that's a limitation in this case?
- it seems like you are mostly addressing the question of
whether benzene increases risk of leukaemia, and not answering
how it does that
I hope you find this useful! Let me know if you have any questions