Aerosols?

Biosolids contain varying concentrations of macroand micronutrients required for plant growth. Like N, P in biosolids is present in both organic and inorganic

forms, but the majority (70 to 90 percent) of this P is inorganic. This inorganic P is present as aluminum (Al), calcium (Ca) and iron (Fe) phosphates and adsorbed to Al, Fe and manganese (Mn) hydrous oxides; also, some organic P is

converted to inorganic P by mineralization. Unlike N, P is not mobile and leaching of P to groundwater is insignificant. Repeated applications of biosolids at Nbased rates, however, can cause P to accumulate in surface soils over time and increase the risk of nonpoint source pollution losses to surface waters.

Thus for biosolids application strategies to be sustainable for land application programs P loadings will need to be considered.

Another class of emerging contaminants you might consider are antibiotics, there are some studies that have shown that they have a medium to high sorption potential thus have a high chance of partitioning into the biosolids. Other human pharmaceuticals which are bit persistent like carbamezapine might be of interest as well. Another class of pollutants you might want to consider are plasticizers such as phthalates, a good example is di-ethylhexyl phthalate which have been found in various matrices and can be considered quite ubiquitous. My advise is when choosing organic pollutants which might be bioavailable to plants after biosolid soil amendments is you need to see if the log Kow of the chemical is greater than 4.0 otherwise if it is less than 2.50-4.0 then it has very low sorption potential and might no be found in the biosolids. On the flip side a too high log Kow means the compound is strongly sorbed to the biosolid thus might not be bioaccessible to the plants.

Good luck.

Very interesting. In some cases P is quite mobile and in Ireland I'd responsible for the vast majority of groundwater at poor status. Thanks for all the advice. Anyone know about aerosols ?