%0 Journal Article
%T Impacts of Triclosan in Greywater on Soil Microorganisms
%A Danielle I. Harrow
%A Jill M. Felker
%A Katherine H. Baker
%J Applied and Environmental Soil Science
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/646750
%X The use of greywater for irrigation is becoming a common practice in arid regions such as the Southwestern US, the Middle East, Australia, and China. While greywater supplies nutrients to soil ecosystems, the possible impact of trace contaminants, particularly pharmaceuticals and personal care products, has not been determined. This paper examined the impact of triclosan, an antibacterial agent commonly added to consumer products, on microbial populations and microbial diversity in soil irrigated with greywater. While there was no change in the total number of heterotrophic microorganisms in the soil, both the types and the antibiotic resistance of the microorganisms were significantly influenced by triclosan. The proportion of the microbial isolates resistant to antibiotics increased while at the same time, overall diversity of the microbial community decreased. 1. Introduction Greywater (GW) is the used water from households,excluding sewage from toilets and, in some countries, waste materials from food preparation [1每3]. Greywater accounts for between 50 to 80% of wastewater coming from individual households [3每5]. The use of GW for the irrigation of lawns, ornamental plants, and other landscape vegetation has become an accepted practice in the Southwest US, the Middle East, and the Australian dry lands [4每6]. While GW irrigation is practiced primarily in arid regions, changing climate patterns, increased water demand associated with urbanization, and increased awareness of the need for water conservation will likely make water reuse more important in temperate regions [7每10]. Domestic GW differs in composition from typical domestic wastewater [11每13]. Greywater is highly variable in composition depending on the number and lifestyle of the residents in a household [11, 14, 15]. Greywater is notable for the high concentration of soaps, detergents, and oils it contains [12, 16]. In addition, GW has pharmaceuticals and personal care products (PPCPs), including antimicrobial agents such as triclosan, at concentrations equal to or higher than those in domestic wastewater [2, 17]. Triclosan (TCS; 5-chloro-2-(2, 4-dichlorophenoxy) phenol; CAS no. 9012-63-9) is the most commonly used antibacterial agent in the US. Current estimates are that the discharge of this compound into the US environment is in the range of 300,000每500,000ˋkgˋyrˋ1 and use is increasing rapidly [18每21]. Triclosan is found in numerous products including clothing, toys, toothbrushes, rubber, hand soaps, toothpaste, deodorants, and laundry detergents [20]. A concentration of 0.1每0.3% of
%U http://www.hindawi.com/journals/aess/2011/646750/