What is the decomposition of the k2co3 look

Plastic in the sea

Even if some types of plastic are remarkably long-lived, they will eventually break down. Ultraviolet (UV) radiation plays a crucial role in the decomposition of plastic. Since UV light is absorbed very quickly by water, it generally takes longer for plastic to decompose in water than on land (Andrady 2003). However, the decomposition also depends on the temperature, polymer type, additives and fillers (Andrady et al. 2003). Little research has been done on what happens to plastic that sinks to the seabed. It is believed, however, that plastic is largely insensitive to degradation once it is protected from UV radiation (Goldberg 1997). Nonetheless, there is evidence that plastic parts in the ocean may be susceptible to bacterial decay (Harshvardhan and Jha 2013; Zettler et al. 2013). At the same time that plastic was revealed to be the main cause of marine pollution, it was discovered that plastic waste is decomposed by photodegradation and oxidation (Scott 1972; Cundell 1974). Scott (1972) reported how some plastic parts on beaches became brittle and could be broken into fine particles under low pressure. The apparent lack of decomposed plastic around such parts led him to believe that the particles "were clearly absorbed by the environment" (Scott 1972, p. 36). Thompson et al. (2004) showed that microscopic plastic particles and fibers are ubiquitous causes of marine pollution. Like larger plastic parts, “microplastics” (Ryan and Moloney 1990) can also be detected in all oceans and deep-sea sediments (van Cauwenberghe et al. 2013).

There is an ongoing debate regarding the size limit of “microplastics” (Thompson 2015). Andrady (2011) discussed the need for three distinctions:

Mesoplastics (500 μm – 5 mm), microplastics (50–500 μm) and nanoplastics (<50 μm). Each of these has its own physical properties and effects on nature. Depending on the upper size limit, industrial pellets are taken into account in this division or not. Even with a narrow view, microplastics are not only created when larger plastic parts decompose. Some cosmetics, hand washing agents and particles in cleaning blasters contain small (<500 μm) plastic balls that were specially manufactured for this purpose (Zitko and Hanlon 1991; Gregory 1996), the so-called primary microplastics (Cole et al. 2011). Due to public pressure, a large chemical company has already been forced to phase out the use of plastic flour in its products by 2015.

Much of the criticism against microplastics is due to its introduction of persistent organic pollutants (POP) into the marine food chains (Cole et al. 2011; Ivar do Sul and Costa 2014). Some additives that are used to change the properties of plastic are biologically active and can influence development and reproduction (Oehlmann et al. 2009; Meeker et al. 2009). Water-repellent POPs in the sea also attach to plastic parts (Carpenter et al. 1972; Mato et al. 2001; Teuten et al. 2009) and the smaller the particle, the better they accumulate toxins (Andrady 2011). Smaller parts are also swallowed by lantern fish (Boerger et al. 2010), which in turn represent an important component in the food chain of many marine ecosystems (Davison and Asch 2011). The path of POPs is discussed in more detail by Rochman (2015), but it should be noted that through strict controls on the use of various POPs (e.g. printed circuit boards, HCH, DDT and their derivatives), the concentration of these in plastic pellets during the last Has been reduced for decades (Ryan et al. 2012).

I like it:

LikeLoading ...