Analysis of organic pollutants in sewage sludges from the Valencian community (Spain).

Seventeen sewage sludges were studied to analyse, with the minimum number of steps, the organic pollutants that the European Union proposes to be controlled for land application. The compounds determined were a selection of polycyclic aromatic hydrocarbons (PAHs); a selection of polychlorinated biphenyls (PCBs); di(2-ethylhexyl)phthalate (DEHP); nonylphenolic compounds, including nonylphenol (NP) and nonylphenol ethoxylates with 1 and 2 ethoxy groups (NP1EO + NP2EO); extractable organic halides (EOX); and linear alkylbenzene sulphonates (LAS) with an alkylic chain of 10 to 13 carbon atoms. The results were compared with the proposed regulatory limit values, and it was observed that NP + NP1EO + NP2EO and LAS exceeded the maximums in most samples, and DEHP exceeded some of them, whereas PAHs, PCBs, and EOX almost always went beyond the limits. The values obtained are similar to those from other countries, and it can be said that it is difficult to comply with the limits for NP + NP1EO + NP2EO and LAS in many of them, although this latter parameter was not considered in the study carried out by Leschber (2004) concerning the toxicity of sewage sludge. Statistical multivariant analysis was used to look for some relationship between the results of pollutants and the characteristics of the samples, and it was found that the ratio of NP1EO + NP2EO to NP was related to sludge treatment at the sewage plant. At the same time, it was seen that the higher values of organic pollutants belonged to digested sludges.