Construcción del módulo experto

In the 1970s, the possibility of using detergents in the removal of oil from feathers was first investigated by British scientists (Croxall, 1972; Harris and Smith, 1977; Smail, 1978). A variety of powder detergents (ArielTM, Bio-DazTM, KudosTM soap flakes, OmoTM, SurfTM) and washing-up liquids (VillageTM, Co-op GreenTM, Fairy LiquidTM, WinfieldTM, KeynoteTM, LuxTM, PalmoliveTM, QuixTM, SqueezyTM) were tested (Croxall, 1972; Cooper and Eley, 1979; McCulloch and Reilly, 1984). In the United States, researchers at the International Bird Rescue Research Centre (IBRRC) also trialled seven different detergents, namely Amber LuxTM, Basic1TM, Conco KTM, Grease ReliefTM, Liquid ConcentrateTM, NokomisTM, Polycomplex A-11TM in the cleaning of 8 types of oil from birds (Berkner et al., 1977). It was found that Amber LuxTM, a biodegradable industrial detergent, was the most effective (Berkner et al., 1977; Newman et al., 2003). The introduction of detergents has led to an improvement in the release and survival rate of oiled birds (Randall et al., 1980; Newman et al., 2003) and, under ideal circumstances, birds can be released in a matter of days instead of months.

In the 1980s, a continuation of this research resulted in the development of more effective surfactant formulations for cleaning oiled birds, in order to reduce cleaning time and to improve the degree of restoration of feather microstructure. For example, a more efficient surfactant, Taski-ProfiTM, was developed, cutting cleaning time in half and improving the thermal insulation properties of the feathers (Jenssen and Ekker, 1989). Also in the 1980s, a concentrate dispersant called OSE750TM (Chemserve, Johannesburg, South Africa) was employed in the cleaning of oiled birds by applying it directly onto the oiled patches, and then rinsing it off with hot water (Kerley and Erasmus, 1987).

In the 1990s, more such cleaning agents were developed. One of these was the formulation developed by Bassères et al. (1994), which showed an oil removal of 90% from standard duck feathers compared to 30% for the control. A normal metabolic rate was found to be recovered one day after cleaning and thermal insulation was restored four days after cleaning. In 1991 a method for evaluating the efficiency of various types of surfactants for the removal of petroleum contaminants from feathers was developed (Bryndza et al., 1991). A synthetic oil, consisting of thirteen polycyclic aromatic

hydrocarbons, representing components present in light crude oils and diesel fuel, was formulated and used as a standard contaminant to assess the removal by different surfactants. It was reported that shampoos and various dishwashing liquids were more suitable than powder detergents with DawnTM dishwashing liquid being the most effective. Other studies have also suggested DawnTM as the most suitable and effective cleaning agent (Welte and Frink, 1991; OWCN, 1999; Newman et al., 2003; Gregory, 2006).

Although DawnTM is now the most popular cleaning agent, recommended for use in wildlife rehabilitation centres worldwide (USFWS, 2002; OWCN-b, 2003; IPIECA, 2004), it does not necessarily work better than other cleaning agents with respect to the removal of some types of contaminants. For example, BiosolveTM or L.O.CTM (Amway) are shown to be more effective than DawnTM in the removal of bunker oil from feathers (Monfils et al., 2000).

Cleaning methods using detergent-based solutions have improved over time and their application has contributed to the survival of thousands of victims (Newman et al., 2003). In some cases, the release rate and survival rate is quite high, up to 95% and 59%, respectively (Giese et al., 2000; Goldsworthy et al., 2000; DPIWE, 2004), with a release rate of 50-60% being common these days (Schmidt, 1997). Other success stories about oiled wildlife rehabilitation using detergent-based technique are also documented (Jessup, 1998; Nel and Whittington, 2003).

However, this technique is labour intensive (Popino, 1993) and requires a lot of warm water (40 - 45 oC) for bathing and rinsing. Moreover, detergents can be toxic and irritating (Berkner et al., 1977) as well as resulting in the removal of preening oil (Jenssen, 1994). It is also time consuming (Popino, 1993) since the entire washing process may take up to 60 min (Welte and Frink, 1991), causing a considerable amount of stress to the bird (Briggs et al., 1997). Damage to the essential microstructure of the feathers can also occur (Ngeh, 2002). Apart from the above, it is not possible to employ this technique in the field since the required facilities are not transportable. Consequently oiled wildlife has to be stabilized initially and transported to a centre for subsequent washing.

It is also important to emphasize that, although a number of different detergent cleaning agents have been tested to date, their removal efficiency is, in general, not well- quantified, an exception being the cleaning product developed by Bassères et al. (1994). The development of an effective cleaning technique that can routinely quantify the efficacy of oil removal and feather damage is important. Current techniques to rehabilitate oiled wildlife are very costly (Sharp, 1996; Estes, 1998). For instance, after the Exxon Valdez oil spill, approximately $41 million was spent on the rescue, treatment and release of 800 birds (Sharp, 1996) and roughly $17 million on sea otters (Estes, 1998).

Therefore, there are ongoing concerns about oiled bird rescue and rehabilitation using detergent techniques (Jenssen, 1994; Anderson et al., 1996; Sharp, 1996; Schmidt, 1997; Briggs et al., 1997; Estes, 1998; Heubeck et al., 2003; Ronconi et al., 2004), and the search for more effective cleaning techniques and agents continues.

Figure 1.4: A cartoon that indicates the problem of cleaning oiled birds in the field using detergent techniques (Eureka, 1999).