Straub T M, Pepper I L, Gerba C P
Department of Soil and Water Science, University of Arizona, Tucson 85721.
Rev Environ Contam Toxicol. 1993;132:55-91. doi: 10.1007/978-1-4684-7065-9_3.
Sewage sludge is a complex mixture of organic and inorganic compounds of biological and mineral origin that are precipitated from wastewater and sewage during primary, secondary, and tertiary sewage treatment. Present in these sludges are significant numbers of microorganisms that include viral, bacterial, protozoan, fungal, and helminth pathogens. The treatment of sludge to reduce biochemical oxygen demand, solids content, and odor is not always effective in reducing numbers of pathogens. This becomes a public health concern because the infectious dose for some of these pathogens may be as low as 1 particle (virus) to 50 organisms (Giardia). When sludge is applied to land for agricultural use and landfill compost, these pathogens can survive from days (bacteria) to months (viruses) to years (helminth eggs), depending on environmental conditions. Shallow aquifers can become contaminated with pathogens from sludge and, depending on groundwater flow, these organisms may travel significant distances from the disposal site. Communities that rely on groundwater for domestic use can become exposed to these pathogens, leading to a potential disease outbreak. Currently, methods to determine the risk of disease from pathogens in land-disposed sludge are inadequate because the sensitivity of pathogen detection is poor. The application of recombinant DNA technology (gene probes and polymerase chain reaction) to environmental samples may provide increased sensitivity for detecting specific pathogens in land-disposed sludge and greatly improved risk assessment models for our exposure to these sources of pathogens.
污水污泥是一种复杂的混合物，包含生物源和矿物源的有机和无机化合物，这些化合物是在一级、二级和三级污水处理过程中从废水和污水中沉淀出来的。这些污泥中存在大量微生物，包括病毒、细菌、原生动物、真菌和蠕虫病原体。对污泥进行处理以降低生化需氧量、固体含量和气味，并不总能有效减少病原体数量。这成为一个公共卫生问题，因为其中一些病原体的感染剂量可能低至1个颗粒（病毒）到50个生物体（贾第虫）。当污泥用于农业土地和垃圾填埋场堆肥时，这些病原体可以存活数天（细菌）到数月（病毒）到数年（蠕虫卵），具体取决于环境条件。浅层含水层可能会被污泥中的病原体污染，并且根据地下水流情况，这些生物体可能会从处置地点传播相当远的距离。依赖地下水供家庭使用的社区可能会接触到这些病原体，从而导致潜在的疾病爆发。目前，确定土地处置污泥中病原体致病风险的方法并不完善，因为病原体检测的灵敏度较差。将重组DNA技术（基因探针和聚合酶链反应）应用于环境样本，可能会提高检测土地处置污泥中特定病原体的灵敏度，并大大改进我们接触这些病原体来源的风险评估模型。
