) Denser varieties of plastics such as nylons tend to submerge in the water column and even reach the coastal sediment. A recent significant finding is that minute fragments of plastic debris, termed microplastics, occur in oceans worldwide (Barnes et al., 2009) including even in Antarctica (Zarfl and Matthies, 2010). Microplastics, a form of man-made litter, have been accumulating in the oceans for at least over the last four decades (Thompson et al., 2004 and Thompson et al., 2005). Sampled from surface waters or from beach sand this fraction of litter includes virgin resin pellets, compounded masterbatch pellets and smaller

fragments of plastics derived from the larger plastic debris (Moore, 2008). The term ‘microplastcs’ and ‘microlitter’ has been defined differently by various researchers. Gregory and Andrady (2003) defined microlitter as the Staurosporine solubility dmso barely visible particles that pass through a 500 μm sieve but retained by a 67 μm sieve (∼0.06–0.5 mm in diameter) while particles larger than this were called mesolitter. Others (Fendall and Sewell, 2009, Betts, 2008 and Moore, 2008),

including a recent workshop on the topic (Arthur et al., 2009) defined the microparticles as being in the size range <5 mm (recognising 333 μm as a practical lower limit when neuston nets are used for sampling.) Particles of plastics that have dimensions ranging from a few μm to 500 μm (5 mm) are commonly present in sea water (Ng and Obbard, 2006 and Barnes et al., 2009). For clarity, this size range alone is referred to as ‘microplastics’ www.selleckchem.com/products/Trichostatin-A.html here; the larger particles such as virgin resin pellets are referred to as Dynein ‘mesoplastics’ after Gregory and Andrady (2003). Persistent organic pollutants (POPs) that occur universally in sea water at very low concentrations are picked

up by meso-/microplastics via partitioning. It is the hydrophobicity of POPs that facilitate their concentration in the meso-/microplastic litter at a level that is several orders of magnitude higher than that in sea water. These contaminated plastics when ingested by marine species presents a credible route by which the POPs can enter the marine food web. The extent of bioavailability of POPs dissolved in the microplastics to the biota (Moore, 2008) and their potential bio-magnification in the food web (Teuten et al., 2007) has not been studied in detail. Unlike larger fragments microplastics are not readily visible to the naked eye; even resin-pellets (mesoplastics) mixed with sand are not easily discernible. Net sampling does not of course collect the smaller microplastics and no acceptable standard procedure is presently available for their enumeration in water or sand. The following is only a suggested procedure derived from published reports as well as personal experience of the author. Water samples are filtered through a coarse filter to remove mesolitter.