Talk:Persistent organic pollutant

Latest comment: 1 year ago by Leyo in topic Why plastics are not considered a POP?

This article was the subject of a Wiki Education Foundation-supported course assignment, between 24 January 2022 and 16 May 2022. Further details are available on the course page. Student editor(s): Parker720 (article contribs).

Long range transport edit

The section on LRT seems to be self-contradictory. Satyrium 13:45, 17 August 2006 (UTC)Reply

Rational Skepticism edit

Not withstanding the scientific nature of POPs/PBTs and the need to expand this article, I'm intrigued by the attention of the Rational Skepticism Project in this article. Is there concern that article itself is biased or is this an attempt to attract someone qualified to revamp? Is this tag being applied to every scientific topic? A comment by Pustelnik who posted the tag would be welcomed. Kmarkey (talk) 14:57, 31 December 2007 (UTC)Reply

While agree that this article is dire need of improvement/expansion, I do not think the Rational Skepticism Project tag is warranted, and I have removed it. Yilloslime (t) 04:50, 12 February 2008 (UTC)Reply

Trends edit

move here from article space, not clear what this is saying and no references (it was tagged as section for cleanup) RJFJR (talk) 15:54, 31 December 2007 (UTC)Reply

The general trend of POPs is the following:

  • Synthesis and development.
  • Increased use over large areas in Europe and North America.
  • Concerns over their persistence, bioaccumulation, and bioconcentration.
  • Restricted use.
  • Reduced emissions, as well as bans and controls.

Natural Sources edit

There is a sentence in the first section that mentions "natural sources of POPs" which is tagged as needing clarification. It seems to me that, while it could be argued that by definition "pollutants" must be produced or introduced into the environment by humans, if you accept them being potentially naturally occurring, Ciguatoxin would be a good example. It is organic, produced by dinoflagellates, bioaccumulates up the subtropical reef fish food chain, and is poisonous to humans. However, I was not able to find any source material specifically describing Ciguatoxin as a POP.

(Sflanker (talk) 18:06, 2 February 2012 (UTC))Reply


Natural Sources of POP's should be expanded upon and clarification is needed as to what "potentially naturally occurring" means.

Yogi44 (talk) 23:17, 2 February 2015 (UTC)yogi44Reply

Proposed Plan to Extend Page edit

Persistent Organic Pollutant

Introduction

  1. Compounds – brief list of various compounds that are known to be POPs, “dirty dozen”
    1. Aldrin
    2. Chlordane
    3. Dieldrin
    4. Endrin
    5. Heptachlor
    6. Hexachlorobenzene
    7. Mirex
    8. Toxaphene
    9. Polychlorinated biphenyls (PCBs)
    10. DDT
    11. dioxins
    12. polychlorinated dibenzofurans
    13. α-Hexachlorocyclohexane
    14. β-Hexachlorocyclohexane
    15. Chlordecone
    16. Hexabromobiphenyl
    17. Hexabromodiphenyl ether and heptabromodiphenyl ether
    18. Lindane (gamma-hexachlorocyclohexane )
    19. Pentachlorobenzene
    20. Tetrabromodiphenyl ether and pentabromodiphenyl ether
    21. Perfluorooctanesulfonic acid (PFOS), its salts and perfluorooctanesulfonyl fluoride (PFOSF)
    22. Endosulfan
    23. Hexabromocyclododecane
  2. Chemical properties
    1. Chlorine
    2. Aromatic ring
  3. Long-range transport
  4. Biomagnification
  5. Health Effects
    1. Cancer
    2. Cardiovascular disease
    3. Obesity
    4. Exposure during pregnancy
      1. Transport across the placenta
      2. Gestational weight gain
      3. Birth outcomes
    5. Endocrine disruption
    6. Diabetes
    7. Reproductive system
    8. Immune system
  6. Stockholm Convention on Persistent Organic Pollutants
  7. Government Regulation of POPs
    1. USA compared to EU consideration of POPs
  8. POPs in the Developing World
  9. POPs in Urban Areas and Indoor Environments

— Preceding unsigned comment added by Chingla (talkcontribs)

A few comments on this proposal:
--Leyo 08:04, 26 March 2014 (UTC)Reply

References edit

  1. ed. Harrad, S., "Persistent Organic Pollutants" (2010).
  2. Walker, C.H., "Organic Pollutants: An Ecotoxicological Perspective" (2001).
  3. Vizcaino, E., Grimalt, J.O., Fernández-Somoano, A., Tardon, A. Environ Int. 2014 Jan 27;65C:107-115. doi: 10.1016/j.envint.2014.01.004. <http://www.ncbi.nlm.nih.gov/pubmed/24486968>.
  4. Ljunggren, S.A., Helmfrid, I., Salihovic, S., van Bavel, B., Wingren, G., Lindahl, M., Karlsson, H. Environ Int. 2014 Jan 25;65C:93-99. doi: 10.1016/j.envint.2013.12.017. <http://www.ncbi.nlm.nih.gov/pubmed/24472825>.
  5. Vafeiadi, M., Vrijheid, M., Fthenou, E., Chalkiadaki, G., Rantakokko, P., Kiviranta, H., Kyrtopoulos, S.A., Chatzi, L., Kogevinas, M. Environ Int. 2014 Jan 2;64C:116-123. doi: 10.1016/j.envint.2013.12.015. <http://www.ncbi.nlm.nih.gov/pubmed/24389008>.
  6. Wania, F., MacKay, D. (1996). Tracking the Distribution of Persistent Organic Pollutants. Environmental Science & Technology. 30 (9), 390A-396A. <http://pubs.acs.org/doi/abs/10.1021/es962399q>.
  7. Jones, K.C., de Voogt, P. (1999). Persistent organic pollutants (POPs): state of science. Environmental Pollution. 100, 290-221. <http://www.sciencedirect.com/science/article/pii/S0269749199000986>.
  8. Reid, B.J., Jones, K.C., Semple, K.T. Bioavailability of persistent organic pollutants in soils and sendiments - a perspective on mechanisms, consequences and assessment. (2000). Environmental Pollution. 108, 103-112. <http://www.sciencedirect.com/science/article/pii/S0269749199002067>.
  9. Lee, D.H., Lee, I.K., Song, K., Steffes, M., Toscano, W. Baker, B.A., Jacobs, D.R. (2006). A Strong Dose-Response Relation Between Serum Concentrations of Persistent Organic Pollutants and Diabetes. Diabetes Cares. 29(7), 1638-1644. <http://care.diabetesjournals.org/content/29/7/1638.short>.
  10. Beyer, A., MacKay, D., Matthies, M., Wania, F., Webster, E. (2000) Assessing Long-Range Transport Potential of Persistent Organic Pollutants. Environmental Sciences & Technology. 34(4), 699-703. <http://pubs.acs.org/doi/abs/10.1021/es990207w>.
  11. Vasseur, P., Cossu-Leguille, C. (2006). Review: Linking molecular interactions to consequent effects of persistent organic pollutants (POPs) upon populations. Chemosphere. 62, 1033-1042. <http://www.sciencedirect.com/science/article/pii/S0045653505007630>.
  12. Kelly, B.C., Ikonomou, M.G., Blair, J.D., Morin, A.E., Gobas, F.A.P.C. (2007). Food Web-Specific Biomagnification of Persistent Organic Pollutants. Science. 317, 236-239. <http://www.sciencemag.org/content/317/5835/236.short>.
  13. Vallack, H.W., Bakker, D.J., Brandt, I., Broström-Ludén, E., Brouwer, A., Bull, K.R., Gough, C., Guardans, R., Holoubek, I., Jansson, B., Koch, R., Kuylenstierna, J., Lecloux, A., Mackay, D., McCutcheon, P., Mocarelli, P., Taalman, R.D.F. (1998). Controlling persistent organic pollutants - what next? Environmental Toxicology and Pharmacology 6, 143-175. <http://www.sciencedirect.com/science/article/pii/S1382668998000362>.
  14. El-Shahawi, M.S., Hamza, A., Bashammakhb, A.S., Al-Saggaf, W.T. (2010). An overview on the accumulation, distribution, transformations, toxicity and analytical methods for the monitoring of persistent organic pollutants. Talanta. 80, 1587-1597. <http://www.sciencedirect.com/science/article/pii/S0039914009007620>.
  15. Lohmanna, R., Breivikb, K., Dachsd, J., Muire, D. (2007). Global fate of POPs: Current and future research directions. 150, 150-165. <http://www.sciencedirect.com/science/article/pii/S0269749107003028>.
  16. Dirinck, E., Jorens, P.G., Covaci, A., Geens, T., Roosens, L., Neels, H., Mertens, I., Van Gaal, L. (2011). Obesity and Persistent Organic pollutants: Possible Obesogenic Effect of Organochlorine Pesticides and Polychlorinated Biphenyls. Obesity. 19(4), 709-714. <http://onlinelibrary.wiley.com/doi/10.1038/oby.2010.133/full>.

deletion of category :endocrine disruptors edit

@Leyo:: thank you for informing me that POP's and endocrine disruptors are two different "concepts" in your edit summary explaining the deletion of my edit adding the latter. For ease, lets look at the Stockholm twelve: if you would be so kind to point out one that is not an endocrine disruptor. Thanks.--Wuerzele (talk) 07:43, 26 March 2014 (UTC)Reply

Hexabromocyclododecane is an example, but this is not the point. The article in about POPs in general, not restricted to those under the Stockholm Convention. And since being a POP or EDC is independent, a compound that fulfills both criteria needs to be categorized with the two respective categories. See also the word many in Persistent organic pollutant#Endocrine disruption. --Leyo 07:52, 26 March 2014 (UTC)Reply
Leyo, thanks for your reply. unfortunately you are mistaken. ample evidence by now that this brominated flame retardant is an ED. Which makes me wonder how you arrived at this reply. i fear it may have been by looking at Hexabromocyclododecane, correct me if I am wrong. we could play this game for a while, you could ping me when you find any POP's that arent endocrine disruptors.--Wuerzele (talk) 03:53, 27 March 2014 (UTC)Reply
As I mentioned above, this is not the point. A POP is not by definition an EDC. --Leyo 08:16, 27 March 2014 (UTC)Reply

correcting references and spelling and what not edit

@Jonesey95: its nice that you fix errors, thanks. could you please wait until someones done with a little subsection? i consider adding the meat of the matter, rewriting convoluted unreferenced half truths and attributing references the primary work, rather than crossing each t and dotting each i, which is the second step. please give a little room before you jump in. looks like that happened to you before, but maybe nobody ever told you. edit conflicts are annoying interruptions. i'll leave the page now and you can edit to your heart's desire, since it needs tons of work.--Wuerzele (talk) 22:15, 27 March 2014 (UTC)Reply

Sorry about that. I tend to edit articles with citation syntax errors in batches of 20 to 30 without looking at each article's history. I speak for myself, and probably for any editor who does the sort of gnome work that I do, in saying that I'm fine with reversion or overwriting of my edits, as long as they are reimplemented (or done in a better way) in a timely fashion. – Jonesey95 (talk) 23:32, 27 March 2014 (UTC) ---Jonesey95 I see. I hope you understood what I was saying, doing non-automated work here; And I do look at the editing environment.--Wuerzele (talk) 01:40, 28 March 2014 (UTC)Reply

@Wuerzele: Thank you for moving the citation from the inappropriate reference list to the text as footnotes. I asked the users who added this list to help. --Leyo 22:30, 27 March 2014 (UTC)Reply

You are welcome,Leyo but please leave the references that I put in alone. They were fine as they were. Under your edit summary "removing one reference that was in a footnote" you ALSO cut dates and accessdates in my correctly entered references. While this info may seem not essential to you, it actually can be. Adding to a reference is ok, but deleting in it rarely. In the 24 h I have been here I have yet to see you add anything constructively, so far just criticizing, reverting and deleting. May I suggest if you have nothing else to do, to work on more pressing things, like helping to find the numerous missing citations for statements people have unloaded here. --Wuerzele (talk) 01:40, 28 March 2014 (UTC)Reply
I do not agree with your judgment, except that I only made small edits. The problem with the unreferenced text originates from this large addition. The user added several footnotes yesterday after having been asked to do so by me. I only removed access dates from references to scientific articles. As opposed to websites (that might change later), they are unnecessary in these cases. --Leyo 08:15, 28 March 2014 (UTC)Reply

Review of Article edit

General: Great job overall. The article is very comprehensive and thorough. It flows very nicely and the subheadings make it easy for the reader to follow the information being presented. I pointed out a few sections that I think could use more citations and wikilinks, but in general the citations were good and the wikilinks were helpful. I also found the See Also section very helpful for further reading. I think the introduction is very balanced. It provides the reader with a lot of information that is scientific yet easily understood. The paragraph on health concerns is very matter-of-fact and rather than sounding biased it merely states evidence. Your introduction also considers the global stance on POPs rather than the view of only one country or region, which is good.

Compounds: I really appreciated the fact that the compound’s use, half-life, and mode of human exposure are included. That provides the reader with a very comprehensive look at the scope of these compounds.

  • Chlordane – The end of the first sentence is awkwardly phrased. I would take a look at it.
  • Dieldrin – The way Dieldrin is made from Aldrin is not very clear. What are the effects of Dieldrin and Endrin on humans? Are they unknown?
  • Polychlorinated dibenzofurans – This section states that it stays in the environment for long periods but this lack of specificity is not in keeping with the specifics included in the rest of the article. If you cannot find an exact number I would attempt to find a rough estimate.
  • After the initial 12 compounds the mode of human exposure is no longer included. Is this information less readily available for the compounds later added to the list?
  • HexaBDE – What are the known health/environmental affects of this?
  • TetraBDE & PentaBDE – I’m confused about the difference between pentaBDE and commercial pentaBDE. Is there a difference? If not, that is not clear in this paragraph.
  • PFOS – You state that these bind to proteins in the blood and liver, but what exactly would that do to a person? Is that more detrimental to people who have preexisting health problems or can this compound seriously harm an otherwise healthy individual?
  • Endosulfans – It says that these are either banned or intended to be phased out globally, but this is vague. In how many countries is it banned and how many countries intend to phase it out and when? Are there countries that are noncompliant? For what reasons?

Chemical Properties: This section is comprehensive yet concise, which is well done. It nicely explains how these compounds easily bioaccumulate. The last sentence, however, is a bit of a run-on and the second half of the sentence could actually be reworded for greater clarity.

Long-range Transport: I would like to see the list of organic fluids set in parentheses linked to their respective pages. Other than that I thought this section was enlightening.

Bioaccumulation: The third sentence in this section about biomagnification could be reworded or broken up into two sentence and expanded on for more clarity of what exactly is going on between trophic levels.

Additive and Synergistic Effects: I think there needs to be wikilinks in this section, especially for the concepts “additive” and “synergistic”. This is a good section to include though, particularly since it points out the flaws of certain research and the reality of the way these compounds impact the body.

Health Effects I wonder why it is that serum levels are higher in females than in males. There must be research on this fact; what conclusions have scientists come up with?

  • Endocrine disruption – This paragraph should include citations, particularly when referencing the 2002 study. I liked how you brought in the fact that even low levels of exposure during development can have devastating impacts in the future; that raised awareness of the severity of these compounds. However, I was confused by the fact that exposure during non-critical developmental timeframes may not lead to health complications when in the previous section the health risks including cancer are cited for many of the compounds. Do you mean the specifically complications in the endocrine system?
  • Reproductive system – I would like to see more wikilinks in this section, possibly for the terms “puberty” and “endometriosis”. Again, the 2002 study should be cited. I think an explanation of how these aberrations in the reproductive system affect reproduction overall could be informational.
  • Exposure during pregnancy – I like how this section is further broken up into smaller subsections; that helps the organization. For the Transfer Across the Placenta section, I thought the explanation of the study was confusing. What exactly is the point you are trying to make about the serum levels versus the umbilical cord and placentas? For the Gestational Weight section, there are some grammatical errors throughout the paragraph that made it hard to read and understand. I would go back through this paragraph and make sure the point you are trying to make is clear.
  • Obesity – It might be helpful to explain what negative correlations and positive correlations mean in terms of the study and the compounds’ affects.
  • Diabetes – When talking about the study, describing what the other variables that were adjusted are would ensure that the description of the study is more comprehensive. Did the study provide a possible explanation for why the different exposure levels and times changed the chances of developing diabetes?

Stockholm Convention: This section is well done but I would like to see some citations to back up what is being said. However, I’m wondering if this section would have flowed better in the beginning of this article. This convention was mentioned in the introduction and is the basis for the Compounds section, so it actually might help to have this background information in the beginning.

POPs in urban areas and indoor environments I would reread this section again and make sure the point you’re trying to make is clear because I found it a bit confusing and it seemed that either words were missing or sentences were combined while editing that weren’t combined seamlessly. But I think the information you included is important and very informational.

Kglobalhealth (talk) 01:26, 10 April 2014 (UTC)Reply

Peer review of the article edit

In general, the article is well organized and flows pretty well. There are great details and examples provided.

Introduction provides good explanation, or general idea, of persistent organic pollutant. However, it would be helpful if some kind of chemical information (perhaps a chart) is provided along with explanation. I was able to see a separate section for chemical properties, but visual chart would help the readers a bit more (or it would be helpful if the chemical property section is moved so that readers can understand the properties before getting into other issues or information on POPs).

For the compounds section, it was very great to see each compound with its explanations. However, some compounds, such as aldrin, dieldrin, endrin, etc, compounds’ effects on humans were not explained in detail or were unclear. Although health effects section was provided below (which I found very helpful), it would be great to see general health effects on humans for each compound!

Like I stated above, chemical properties section was clear, but it would be better if this section was moved towards beginning (and perhaps rearranged in a form of chart or other visual method).

Long-range transport and bioaccumulation sections were well-explained and provided clarification in understanding POPs. However, I would like to see citations after each sentence that includes information from different sources, not all at once at the end of the paragraph. It would be easier for the readers to access sources for the information if needed.

For the additive and synergistic effects section, I would like to see sources that back up the information/experiments. Some examples of experiments along with some explanation would be nice. In addition, some examples of synergistic effects of mixture of POPs and other chemical mixtures would be a great help in better understanding of this section.

For the health effects section, different effects were well organized. However, I think this section needs citation of the sources (ex: a 2002 study) – needs clarification on the case studies.

Stockholm Convention on Persistent Organic Pollutants section would be better with citations on information provided.

It was nice to see that you addressed POPs in urban areas and indoor environments, but it was a bit confusing reading the section. You mentioned that “recent studies of indoor dust and air have implicated indoor environments as sources for human exposure via inhalation and ingestion”. It would help if the sources were provided for the studies and some details on the experiment. Also, article says that there are significant indoor POP pollutions. But is there a specific way that increases the indoor pollution? Or do certain activities cause significant increase in indoor POP pollution?

I enjoyed reading your article. Information was helpful and very interesting. Good luck on your final version of the article and I hope the review helped a bit!

Kohw 23:23, 11 April 2014 (UTC) — Preceding unsigned comment added by Kohw (talkcontribs)

POP Review edit

This is a great wikipedia page. It is clear you've done a lot of research and you do an excellent job of staying neutral while presenting research to support your entry. Given how many chemicals there are that are classified as POPs, I think your page will have some heavy traffic!! There are some points where you need to be more consistent in citing. In general, you do a good job and have quality sources vs. quantity. Overall, the largest critiques I have are structural/organizational (see below). As with all writing, the grammar and flow is a never ending process of improvement, but overall you do a good job. I did go through and directly edit some things to help out!

It would be helpful to add current research going on as POPs and how corporations are responding to the international convention. In addition, there is a lot more information you can provide on various environmental effects POPs have in our world. You mention wildlife but what about the environment. DDT decimated Vietnam. I get it is hard to do since every specific POP is different, but perhaps a general, broad section on environmental impacts will be useful. I think some are linked to climate change as well. Are there any numbers you can find to support its environmental impact. Finally, I believe a section on how you clean up these chemicals or handle them might be useful. Once again, it probably varies from chemical to chemical, but i'm sure there is a broad technique that generally works. This section could even be nested under the environmental section.

Once again, this is a GREAT wikipedia page. I'm being very nitpicky and pushy. I truly do think it'll generate a lot of traffic and it is necessary to have. If you have any questions feel free to email me or talk to me after class. I'd be happy to help in any way possible.

Introduction

  • I think the first paragraph can be eliminated entirely and should start with commercial uses seen in the second paragraph. The third and first are redundant, but the third is stronger
  • Overall the introduction was good. The fact that you concluded with the international conference conferred a degree of neutrality and showed its current state in our society today.

Compound

  • If you delete the first paragraph of the introduction, make sure to wikilink: photolytic, chemical, and biological degredation
  • Wikilink porphyria turcica under “HCB”
  • The paragraph on mirex contradicts itself by claiming to be harmless to humans but also a carcinogen. I don't agree with the comments left by another reviewer asking to specify the health effects of DDT. Since you are wikilinking it to another page, I think it suffices to give a brief summary and not have to go too in depth. That is true for all the 12 deadly POPs. I was expecting the compounds section to be more in depth compound analysis. Maybe it is better to rename the section “history of POPS”

Chemical Properties

  • The last two sentences are a bit choppy and could be reworded to flow better.Also, since long range transport is a function of its chemical volatility, maybe it makes more sense to nest the two topics together.

Health Effects

  • The endocrine section needs some grammatical work in terms of flow. Also, the reproductive system, endocrine system, and exposure during pregnancy can all go under “endocrine sections” as they are all rooted in hormone disruption. Perhaps there could be mini sections, but it needs to be condensed and synthesized to avoid being repetitive and to be more organized.
  • Similarly, the obesity, cardiovascular disease, and diabetes are all chronic diseases caused by POPs. I suspect all three have to do with lipoproteins. Is there anyway you can combine them all into one “chronic disease” section describing generally the lipoproteins. Then having subsections diving deeper into its relationship with obesity, cardiovascular disease, and diabetes? I’m not sure if that makes sense.

Stockholm Convention and POP Indoors

Post-Peer Review Edits edit

After reading through all of the peer review comments we thoroughly reviewed the article, rewording areas which were hi-lighted as confusing or too generalized by the reviews, updated . We did some restructuring of the page so that the information might flow more clearly and added a brief section describing the current state of science of control and removal of POPs in the environment. — Preceding unsigned comment added by Chingla (talkcontribs) 13:08, 30 April 2014 (UTC)Reply

Reviewer Comments edit

Great and informative article! The one section i was a little uncertain about was "POPs in urban areas and indoor environments" because the information is much more vague than the rest of the article. Perhaps it would be possible to expand upon the factors of indoor pollution and POPs within the home, as you mention that over time, trends have increased time spent indoors. You mention air and dust, but are there other factors that contribute to the prevalence of POPs and how they are tracked indoors? Just a couple thoughts! Egilmore15 (talk) 20:08, 2 February 2015 (UTC)Egilmore15Reply

Special:Diff/647671378/655220884 edit

Certain sentences do not make sense anymore after these major changes. Some copyediting is needed. Smokefoot, could you make an attempt yourself (after having gone through your changes again)? --Leyo 19:27, 6 April 2015 (UTC)Reply

Oh sorry, I will do that now. --Smokefoot (talk) 21:02, 6 April 2015 (UTC)Reply
Thanks, but that's only partly what I was referring to. Examples are the second section of the introduction and the bullet points on PFOS and HBCD. --Leyo 21:31, 6 April 2015 (UTC)Reply

Redundancy concerning substances on the Stockholm Convention edit

There is a redundancy of Persistent organic pollutant#Stockholm Convention on Persistent Organic Pollutants and Stockholm Convention on Persistent Organic Pollutants#Listed substances. It appeared with this large addition that was made within the Education Program.
I'd suggest that the redundancy is fixed by shortening the section in this article. --Leyo 20:12, 7 April 2015 (UTC)Reply

Smokefoot, unfortunately, didnt fix redundancy but deleted WAY more. I have problems with this massive deletion (-4,800 bytes) of sourced info.--Wuerzele (talk) 03:21, 8 April 2015 (UTC)Reply

glyphosate ??? edit

See here http://www.cdpr.ca.gov/docs/emon/pubs/fatememo/glyphos.pdf . This is about as durable as other substances already mentioned here. -- Kku 16:03, 20 November 2015 (UTC) — Preceding incorrectly signed comment added by Kku

It does not have POP properties. --Leyo 20:42, 20 November 2015 (UTC)Reply


Why plastics are not considered a POP? edit

I’m really interested in this, as to me, some plastics can undoubtedly be classified here, and are in definition a persistent organic pollutant.

I know this is my own classification, however there must be some kind of attribution or reference somewhere! Help! AnonKnowsBest (talk) 17:25, 28 September 2022 (UTC)Reply

Plastics do not fulfill all four POP criteria as set out in the Stockholm Convention. --Leyo 22:18, 28 September 2022 (UTC)Reply

Wiki Education assignment: Toxicology edit

  This article was the subject of a Wiki Education Foundation-supported course assignment, between 10 August 2022 and 8 December 2022. Further details are available on the course page. Student editor(s): ToxicologyVerify (article contribs).

— Assignment last updated by Spmg98 (talk) 17:56, 28 September 2022 (UTC)Reply