Sewage sludge soil pollution, application

Couillard, D. Zhu, S. (1992). Bacterial leaching of heavy metals from sewage sludge for agricultural application. Water, Air, and Soil Pollution, 63, 67-80. 

Davis, R., Carlton-Smith, C., Stark, J., Campbell, J., 1988. Distribution of metals in grassland soils following surface applications of sewage sludge. Environ. Pollut. 49, 99-115. 

Toxicity of natural origin is found in soils formed from Cu sulfide-rich parent rocks, especially when the soil is acid. Bioaccumulation of Cu in humus followed by episodes of reduction can concentrate the element in sulfide form in natural wetlands. Because copper is not only phytotoxic but also a commonly abundant metal pollutant in waste materials, Cu in wastes such as sewage sludges is often the first element to limit land application. 

Toxicity of Zn to plants is most likely to appear in acid soils that have not been subjected to prolonged acid leaching. The rather high potential solubility of Zn " in acid soils, and the fact that Zn is typically a high-concentration pollutant of industrial wastes and sewage sludges, combine to create a significant potential for phytotoxicity from land application of wastes. This is in spite of the fact that Zn toxicity to plants is inherently fairly low. 

Ferreira et al evaluated the use of the traditional linear fit and MLP-ANN models for LIBS calibration. Their aim was to obtain a quantitative multi-elemental method for pollution measurement in soil under sewage sludge application. Two sets of samples, both composed of two kinds of soil, were used for calibration and validation. The target analyte concentrations were determined using a reference analytical method based on ICP-OES. The values determined by LIBS-MLP-ANN showed low prediction errors, good correlations with the concentrations determined by ICP-OES, high accuracy and precision, low limits of detection and best potential to quantify different types of soils. 

---