To assess seawater quality, we use a battery of several parameters (Fecal contamination, microplastics, heavy metals, physicochemical factors..) !
Which one could be the most relevent that can stand alone to give a clear picture of seawater sample!?
This would be an opinion, based more on land based hydrology rather than marine hydrology. Pollution in streams and rivers is seldom static, take a grab sample and one is unlikely to have the answer. But like the canary in the mine shaft, biological indicators by their presence or absence can be effective indicators. But again we might be faced with a battery of biological indicators, depending on the habitat. Even ocean temperature shifts may have significance. It’s a good question, but one might be distracted from the pollution diversity, complexity and spatial variance by trying to name a specific pollutant.
Honored to hear from you Mr. William.
Good answer Sir ! As I have understood from your comment, it is too complicated to stand on one simple way talking about seawater quality (pollution generally) and we should not forget about upstream effects..
Cheers.
Apart from biological indicators, you could consider electrical conductance (or conductivity) which gives some insight in the overall concentration of dissolved solids (in ionic form). At least in freshwater systems, it may indirectly indicate the level of pollution. It's probably just a crude estimation, however. For instance, conductivity also depends on water temperature. In any case, I don't think there is a single parameter that will give a comprehensive picture of seawater quality. If you need to reduce the amount of assessed parameters, it would probably be a good idea to first see which of your measured parameters correlate with each other (and hence more or less indicate the same thing).
Thank you for your response Mr. Eli. Good answer too and pour also in the same reflexion of Mr. Williams.
Best regards.
The question unfortunately starts with how does one define pollution? And then to which pollution are you seeking to study?
I do not believe there is a single parameter that can be used as a surrogate to estimate the total. I do believe it is important to be consistent and thorough across the investigation so the chosen parameters are checked in multiple places at multiple times.
Perhaps it is possible to identify a few specific parameters for each pollution input that you wish to study whether sewage, or plastics, or industrial waste, or stormwater runoff, or agricultural and then evaluate their inputs and outputs over time. That would have some power to evaluate the systems.
Of course since budgets are always a concern I suggest using abundant and easily collected and reasonably accurate information rather than limited difficult analyses to the extent possible to initially map the issues.
Good luck to you in this adventure.
Thank you for your response Mr. Murphy.
Excellent reflexion and good luck to you too.
Best wishes !
I think in addition to the parameters of seawater quality , the most important is how to monitor the quality of seawater, how to detect any change in this quality and how to protect it
How to control all sources of pollution to seawater and what is the most dangerous
Thank you Mr. Wahba for your response. Exactly, the aim after all is Biomonitoring of our ecosystems in order to give a suitable strategy of Protection.
Cheers.
yes we cannot predict the water quality with pollutant content. Physico-chemical analysis have to do in number of sampling locations and repeated time intervals will give good result and further solutions.
Determine the water quality index based on the parameters you measured.
Nagalakshmi Radhakrishnan Thank you for your response. I agree with you, to have a clear view, we must do analysis in a long period and in many spatial points with repetitions.
Regards to you.
Kiprotich Kiptum Thank you for your response. Can you send here any references about water quality indices. It is a good point of view from you.
Best regards!
Physico-chemical properties of sea water are very important and critical to know about the quality of sea water. Of the parameters of sea water, salinity can be considered as one of the important parameters in terms of pollution. Salinity is the measure of the amount of salts in the water. Dissolved ions in water increase salinity. Salts in sea water are mainly sodium chloride, which affect the quality of sea water. They have a critical influence on aquatic biota as every kind of organism has a typical salinity range that it can tolerate.
Thank you @Munira for your response. Indeed, salinity is one of the most relevent parameters and you can't pass a physicochemical study of seawater without giving values of salinity. The same thing when we study harsh environments, measure salinity is inevitable.
Regards to you.
Dear
It depends on your objective, if you need non-conventional source of water so salinity is the most important parameters.
If the sea water is polluted with oil or other pollution sources you will take these parameters in your consideration.
Fecal bacteria as indicator of water quality
Background
In general, increased levels of fecal coliforms provide a warning of failure in water treatment, a break in the integrity of the distribution system, possible contamination with pathogens. When levels are high there may be an elevated risk of waterborne gastroenteritis. Tests for the bacteria are cheap, reliable and rapid (1-day incubation).
Potential sources of bacteria in water[edit]
The presence of fecal coliform in aquatic environments may indicate that the water has been contaminated with the fecal material of humans or other animals. Fecal coliform bacteria can enter rivers through direct discharge of waste from mammals and birds, from agricultural and storm runoff, and from human sewage. However, their presence may also be the result of plant material, and pulp or paper mill effluent.[1]
Human sewage[edit]
Failing home septic systems can allow coliforms in the effluent to flow into the water table, aquifers, drainage ditches and nearby surface waters. Sewage connections that are connected to storm drain pipes can also allow human sewage into surface waters. Some older industrial cities, particularly in the Northeast and Midwest of the United States, use a combined sewer system to handle waste. A combined sewer carries both domestic sewage and stormwater. During high rainfall periods, a combined sewer can become overloaded and overflow to a nearby stream or river, bypassing treatment.
Animals[edit]
Pets, especially dogs, can contribute to fecal contamination of surface waters. Runoff from roads, parking lots, and yards can carry animal wastes to streams through storm sewers. Birds can be a significant source of fecal coliform bacteria. Swans, geese, seagulls, and other waterfowl can all elevate bacterial counts, especially in wetlands, lakes, ponds, and rivers.
Agriculture[edit]
Agricultural practices such as allowing livestock to graze near water bodies, spreading manure as fertilizer on fields during wet periods, using sewage sludge biosolids and allowing livestock watering in streams can all contribute to fecal coliform contamination.. - https://en.wikipedia.org/wiki/Fecal_coliform#Fecal_bacteria_as_indicator_of_water_quality
Thank you @Dilojan for your opinion. Indeed, fecal coliforms give good assumptions about seawater quality...
Sources of BTEX
BTEX refers to the chemicals benzene, toluene, ethylbenzene and xylene.
These compounds occur naturally in crude oil and can be found in sea water in the vicinity of natural gas and petroleum deposits. Other natural sources of BTEX compounds include gas emissions from volcanoes and forest fires.
The primary man-made releases of BTEX compounds are through emissions from motor vehicles and aircrafts, and cigarette smoke. BTEX compounds are created and used during the processing of petroleum products and during the production of consumer goods such as paints and lacquers, thinners, rubber products, adhesives, inks, cosmetics and pharmaceutical products.
BTEX compounds are among the most abundantly produced chemicals in the world.
Common exposure to BTEX
The most common sources of exposure to BTEX compounds are from breathing contaminated air, particularly in areas of heavy motor vehicle traffic and petrol stations, and through cigarette smoke. Exposure to BTEX from water contributes only a small percentage of the total daily intake, compared with inhaled air and dietary sources.
Health standards for BTEX
Public health guidelines for BTEX are available for drinking water in the Australian Drinking Water Guidelines(external link) (ADWG). These guidelines are based on the amount of a chemical that can be ingested every day over a lifetime without adverse effect.
Benzene is a known carcinogen (cancer causing). The ADWG specify that it should not be detected in drinking water at more than 1 part per billion (ppb) †. The remaining chemicals (toluene, ethylbenzene and xylenes) are not recognized as carcinogenic and their drinking water health guidelines are much higher—between 300 and 800 ppb.
In air, different types of guidelines are available for both ambient and occupational settings. In Queensland, the Environmental Protection (Air) Policy 2019 specifies guideline values for benzene, toluene and xylenes in air to ensure protection of human and environmental health.
The ambient air quality objectives to protect human and environmental health are 3 ppb for benzene, 100 ppb for toluene and up to 200 ppb for xylene—based on the ambient concentrations of these chemicals being averaged over a yearly period.
BTEX chemicals occur naturally in underground water sources. So to ensure these levels don’t rise above environmental and human health standards, the use of BTEX in the fraccing process has been strictly regulated, including a ban on adding these chemicals to fraccing fluid.
The following environmental and health standards for BTEX in fraccing fluids ensure that BTEX chemicals are not at a level that will contaminate drinking water or impact on groundwater dependant plants and animals:
https://environment.des.qld.gov.au/management/activities/non-mining/fraccing/btex-chemicals
"In the petroleum refining and petrochemical industries, the initialism BTX refers to mixtures of benzene, toluene, and the three xylene isomers, all of which are aromatic hydrocarbons. The xylene isomers are distinguished by the designations ortho – (or o –), meta – (or m –), and para – (or p –) as indicated in the adjacent diagram. If ethylbenzene is included, the mixture is sometimes referred to as BTEX.
The BTX aromatics are very important petrochemical materials. Global consumption of benzene, estimated at more than 40,000,000 tons in 2010, showed an unprecedented growth of more than 3,000,000 tons from the level seen in 2009. Likewise, the para-xylene consumption showed unprecedented growth in 2010, growing by 2,800,000 tons, a full ten percent growth from 2009.[1]
Toluene is also a valuable petrochemical for use as a solvent and intermediate in chemical manufacturing processes and as a high octane gasoline component." - https://en.wikipedia.org/wiki/BTX_(chemistry)
Detection and occurrence of indicator organisms and pathogens - Article Detection and Occurrence of Indicator Organisms and Pathogens
Article Detection and Occurrence of Indicator Organisms and Pathogens
Indicators of microbial water quality
https://www.who.int/water_sanitation_health/dwq/iwachap13.pdf
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