Chloride is ubiquitous in natural waters and is essential in a wide range of biological functions, including facilitating a variety of ion-exchange mechanisms through trans-membrane chloride channels. It forms salts with each of the major cations (Na, K, Ca, and Mg), but is highly soluble and exists primarily in the environment as a dissociated monovalent anion. Freshwater organisms are generally hyperosmotic in their internal fluids relative to the external environment and maintain an active gradient of chloride across membranes through use of active pumps and/or bicarbonate exchange mechanisms at exterior surface. (ref. ID; 7131)
Toxicity; Toxicity may result from osmotic stress related to overall ionic strength or disruption of individual cellular processes. The toxicity of chloride is in aquatic environments as a result of its tendency to occur at elevated concentrations in effluents from industrial operations that involve subsurface mining (including coal, potash, metal, and diamond mines), and oil and gas extraction. In addition, chlroide salts are widely used in road salts and, consequently stormwater and snow-melt runoff contain high concentrations of chloride in areas of application. (ref. ID; 7131)
Test organisms;
Rotifera: Brachionus calyciflorus (ref. ID; 7131)
Oligochaeta: Lumbriculus variegatus (ref. ID; 7131)
Oligochaeta: Tubifex tubifex (ref. ID; 7131, 7134)

[Chlorine, Cl-]
Test organisms;
Protozoa: Community (ref. ID; 955)

[Chlorinated wastewater]
Test organisms;
Protozoa: Uronema nigricans (ref. ID; 6092)

[Sodium Chlorate] CAS[7775-09-9] UN1495
Chemical formula; NaClO3
Trade name; Chlorex
Purpose for use; Herbicide for complete eradication of weeds in uncultivated soil. (ref. ID; 496)
Test organisms;
Protozoa: Blepharisma undulans (ref. ID; 496)
Protozoa: Colpoda cucullus (ref. ID; 496)
Protozoa: Oikomonas termo (ref. ID; 496)

[Sodium Chloride] CAS[7647-14-5]
Chemical formula; NaCl
Test organisms;
Oligochaeta: Eisenia fetida (ref. ID; 6895, 7012, 7145)
Oligochaeta: Tubifex tubifex (ref. ID; 6968)
Nematoda: Caenorhabditis elegans (ref. ID; 7002)

[Sodium Hypochlorite] CAS[7681-52-9]
Trade name; Sodium hypochlorite (J): Chlorox
Chemical formula; NaOCl
Purpose for use; Fungicide, bactericide.
Test organisms;
Rotifera: Brachionus calyciflorus (ref. ID; 127)