Comparison of Ultra-Sonication and Microwave Extraction Followed by Filtration or Filtration and Solid-Phase Extraction Clean-Up for PAH Determination from Sediment and Sludge: Human Health and Ecological Risk Assessment  
[PERSON]  
1 Department of Scientific Services, Laboratory Services, Umgeni Water, 310 Burger Street, P.O. Box 9, Pietermnitzburg 3201, South Africa 1  
M., Malkambai  
1 Department of Scientific Services, Laboratory Services, Umgeni Water, 310 Burger Street, P.O. Box 9, Pietermnitzburg 3201, South Africa 1  
M., Malkambai  
1 Department of Scientific Services, Laboratory Services, Umgeni Water, 310 Burger Street, P.O. Box 9, Pietermnitzburg 3201, South Africa 1  
P., C., and M., M., M.  
developmental effects and tumours on terrestrial invertebrates [1; 2]. It is thus endorsed by the National Environmental Management: Waste Act of 2008 (NEMWA) that contaminants, including PAHs, are monitored in all aspects of the environment, including water treatment plants [3]. The NEMWA of 2008 ensures the protection of human health and the environment through regulating waste management by providing reasonable measures for the prevention of pollution and ecological degradation in order to secure ecological sustainable development. This Act stipulates the set national norms and standards for the assessment of waste management for landfill disposal in all spheres of government in order to ensure compliance [4]. As PAHs are persistent organic pollutants which do not degrade quickly in the environment, they can be transported and distributed throughout the environment by rain and wind [5]. PAHs have been classified as priority pollutants by the World Health Organisation (WHO) and their presence in the environment and exposure to humans and other living organisms is therefore of great concern [6]. On the one hand, the introduction of PAHs into the environment has increased with the increase in demand for petroleum products, which is one of the original sources of PAHs, amongst others, such as wastewater treatment plants, industrial discharge, etc. Water boards aim to ensure the control of pollution, as the treatment process employed at waterworks produces sludge which, after the dewatering process, is often disposed of in landfills. It is therefore of great importance that the extent of pollution in the landfills and the surrounding areas be assessed. This is per directive given by the South African government through the NEMWA license, which states that all water boards and municipalities need to analyse organics and other pollutants in sludge to ensure compliance. Even though significant research on PAHs and other organic contaminants has been undertaken in developed countries, this still remains a gap in the developing countries, such as South Africa, where limited data (sources and concentration levels) are still a hindrance for policy making [7]. Techniques for the extraction and concentration of PAHs from environmental solid samples, such as soxhlet extraction (SE), microwave-assisted extraction (MAE), ultrasonication extraction (UE), linear shaker (LS) and QuEChERS methodology, are often used for the extraction of organics from solid samples. Soxhlet has been largely used as the benchmark of extraction of PAHs in solid samples as it is a well-studied method. In SE extraction is achieved via a reflux cycle with the use of an appropriate solvent. Although SE has been used successfully, it has its disadvantages, including the use of large volumes of solvents (\(\sim\)300 mL) and being time-consuming (\(\sim\)24 h) and labour-intensive [8]. Extraction with linear shaker can be used in order to reduce the amount of solvent required (\(\sim\)20 mL) for PAHs in solid samples. However, like SE, extraction with the use of a linear shaker is time-consuming, and its sensitivity is only attainable when long shaking times (\(\sim\)20 h) are applied in order to extend the contact time with the solvent. Techniques such as MAE and UE have been used in order to reduce extraction times and promote ease of sample preparation.