Indices for monitoring marine environment: turbidity, total suspended solids, clarity, phytoplanton chlorophyll , eutrophication, pollution indicators, heavy metals, hydrocarbons, remote sensing, Anthropization models impact . For details consult Monitoring of Marne Pollution https://www.sciencedirect.com

@Prof. Sylvester, thank you for the contribution and the link.@

Here you have some of the best,

Article MODIS detects oil spills in Lake Maracaibo, Venezuela

Article Monitoring turbidity in Tampa Bay using MODIS/Aqua 250-m imagery

Article Detection of natural oil slicks in the NW Gulf of Mexico usi...

Article Mapping the pollutants in surface riverine flood plume water...

I hope this will help you

The very important index used to detect the pollution of seawater is Phytoplankton. It's a very sensetive element to the envirment perturbations (Goffart, 2010; de Jonge et al. 2002, Devlin et al. 2007).

A monitoring of microalgaes (phytoplankton) is very usefull because of the appearence of some species known to plorifate quickly in pollution conditions. The result of monitoring can, also, be used to calculate a lot of Indexes, for mesuring the stability of the phytoplankton in marine envirment, such Shannon Index which is very usefull by researchers.

You can also use the shellfish as bioindicators if you want to detect trace metal elements pollution ( Amiard et al., 1985 et 1994; Guevara et al., 2004; Foxall et al., 2000; Abarnou et al., 2013; Bélanger et al., 2009; Kruzynski et al., 2002; Yap, 2007).

Saad Zahra , thank you for your contribution

I'd suggest that you take a look at Angel Borja's work. He has devoted a number of approaches for use in Europe.

https://scholar.google.com/citations?user=U6gHv0cAAAAJ&hl=en

All above suggestion is right, this are standart methods. But real (sinergetic) toxicity you can determing only by biological methods, for example using species-indicator bivalva mussels. If water polluted, the animal close shells and heart activity stay slow. But the methods don't answer what elements present in water. New bioelectronic devices can registrate the parameters. If it interesting I can send materials [email protected]

Richard K Johnson and Petr Mashkin , thank you for your contributions.

Not specific to pollution, but check out this comprehensive work here: http://www.oceanhealthindex.org/

@ Ivan Lizaga thank you somuch for those articles.

@all thank you for all your comments and contribution