[Pharmwaste] Triclosan in the environment - study

[Tenace, Laurie]

http://www.environmentalhealthnews.org/ehs/newscience/triclosan-in-wastewater-kills-bacteria-reduces-algal-photosynthesis/


Antimicrobials murderous in nature.
Nov 10, 2010


Ricarta, M, H Guasch, M Alberch, D Barceló, C Bonnineau, A Geiszinger, M·la Farré, J Ferrer, F Ricciardi, AM Romaní, S Morin, L Proia, L Sala, D Sureda and S Sabater. 2010. Triclosan persistence through wastewater treatment plants and its potential toxic effects on river biofilms. Aquatic Toxicology http://dx.doi.org/10.1016/j.aquatox.2010.08.010.

Antimicrobial compounds that are washed down the drain make it into the environment where they can interfere with the algae and bacteria needed for healthy ecosystem function.

When released into waterways from wastewater treatment plants, the antimicrobial triclosan continues to do what it was designed to do - kill bacteria - and starts doing what it was not designed to do - interfere with photosynthesis in algae.

The results from a study in Spain suggest that triclosan carries a high environmental risk and warrants concern about its presence in waterways. The findings agree with prior studies that find the antimicrobial is toxic to bacteria at levels measured in water.

However, this is one of just a few published studies to report that triclosan can reduce photosynthesis in a type of algae known as diatoms. Through photosynthesis, diatoms produce oxygen and food that other aquatic organisms rely upon. It is estimated that 80 percent of the oxygen in our atmosphere comes from diatoms, making these microscopic organisms essential for life on earth.

Triclosan is an anti-microbial chemical widely used in personal care products, like toothpaste and anti-bacterial hand soap. It is added to cleaning products and is applied to many items, including clothing, toys, shower curtains and kitchenware.

Triclosan is washed down sinks and showers and into wastewater treatment facilities. Because treatment plants are not designed to eliminate organic compounds - like pharmaceuticals, detergents or personal care products - triclosan can remain intact and enter rivers and lakes with the treated wastewater. Triclosan is found in wastewater effluent at concentrations ranging from 0.027 - 2.7 micrograms per liter.

After release into water bodies, it can affect aquatic organisms and contaminate drinking water. Triclosan also breaks down in sunlight to release dioxins, which are powerfully toxic compounds known to cause reproductive and developmental damage to wildlife and humans.

The new study tested the effects of various levels of triclosan on naturally-occurring microbial communities gathered from a river in northeast Spain. The microbes were constantly exposed for 48 hours to a range of triclosan concentrations (0, 0.5, 5, 25, 125, 250 and 500 micrograms per liter) that included levels previously measured in wastewater effluent.

They found that their lowest concentration (0.5 micrograms/liter) reduced bacterial concentrations. The higher doses killed up to 85 percent of the bacterial population.

Triclosan was also toxic to diatoms and reduced photosynthesis at concentrations above 5 micrograms per liter.

The results suggest that triclosan is a risk to aquatic microorganisms and may change the numbers and types of bacteria and diatoms in a microbial community. These changes could lead to alterations in the balance of an ecosystem.

Laurie Tenace
Environmental Specialist
Waste Reduction Section
Florida Department of Environmental Protection
2600 Blair Stone Rd., MS 4555
Tallahassee FL 32399-2400
P: 850.245.8759
F: 850.245.8811
Laurie.Tenace at dep.state.fl.us

Mercury: http://www.dep.state.fl.us/waste/categories/mercury/default.htm

Batteries: http://www.dep.state.fl.us/waste/categories/batteries/default.htm

Pharmaceuticals:
http://www.dep.state.fl.us/waste/categories/medications/default.htm
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Household Hazardous Waste:
http://www.dep.state.fl.us/waste/categories/hazardous/pages/household.htm





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