BCR-484 - Sewage Sludge amended (Terra Rossa) Soil

The sampling of the material (terra rossa soil) was carried out in 1991 in a farm plot  amended with sewage sludge from a water treatment centre located in North-East Catalonia,  Spain. Samples were taken from an area of about 250 m2 with a small shovel to a depth of  about 10 cm and sifted on-site by hand through a 0.5 cm nylon sieve into polyethylene bags.  The samples were taken to the Water Treatment Centre and again sieved through a 20 cm  diameter nylon sieve with a mesh size of 2 mm into polyethylene bags for transport to the  laboratory Analytical Chemistry of the University of Barcelona. The soil was then spread  over a polyethylene sheet and air-dried at 30 oc for one week to a final water content of 1.5  %. The air-dried soil was packed into a 100 litre polyethylene container, tighly sealed and  dispatched to the Environment Institute of the Joint Research Centre of Ispra (Italy) for  homogenisation and bottling.  4  The air-dried ( < 2 mm) soil sample was transferred in total (91 kg) into a mixing drum filled  with dry argon and placed on roll-bed capable of handling 100 kg samples. The  homogenisation of this soil, with its large spread of particle sizes, from just below 2 mm  down to fractions of a micrometer, required particular care. This procedure was, therefore,  carried out by mixing in the drum for over 4 weeks. The bottling procedure was performed  as follows: to prevent segregation of fine particles, 10 samples were taken from the centre  of the drum immediately upon stopping the rotation of the mixing drum, and were placed into  10 pre-cleaned brown glass bottles, each containing a minimum of 70 g of soil. The drum  was again rotated for a further two minutes and a further 10 samples were subsampled in the  same way into bottles. The subsampling and bottling operation was continued until 1000  bottles of the soil were obtained. One hundred bottles, selected sequentially over the whole  bottling procedure were sent to the Macauley Land Use Research Institute for homogeneity  and stability testing.

keywords: environmental materials , soil/sediment ,  biosolids , trace elements , heavy metals , fractionation analysis