CyTiS · Cytostatic compound fate and transport in soil and groundwater

Cytostatic compound fate and transport in soil and groundwater

Cytostatic compounds are used globally as chemotherapy drugs to treat cancer, and increasingly these are outpatient treatments. Up to 90% of the drug can be excreted by the patient, and can therefore enter municipal wastewater systems or, in rural areas, onsite wastewater treatment systems like septic systems. Most municipal systems and septic tanks are not equipped to degrade cytostatic compounds, and consequently these compounds can reach soils directly via leaching fields, through discharge of wastewater treatment plant effluent to holding ponds, or through application of sludge to agricultural fields. The objective of CyTiS was to explore the transport of cytostatic compounds in soil types relevent to leaching fields and agricultural soils which may impact groundwater, and to explore the impact cytostatic compounds have upon microbial soil communities. Because of their genotoxic, carcinogenic, and teratogenic effects, these compounds have the potential to damage ecosystems and people. There is no safe limit for these compounds in drinking water. Very little is known regarding the transport of this wide class of compounds in soil to groundwater, and nothing is known regarding their impact on microbial communities in soils. Healthy and diverse microbial communities are responsible for the degredation of organic contaminants in soils, and if cytostatic compounds impact either the health or diversity of these communities it may impede the remediation of many other contaminants and organic wastes. The first aim of this project was to use sorption studies to assess the potential for cytostatic compounds to be transported in soil environments to groundwater. Sorption of chemicals to soil is a process that can slow or prevent their transport to groundwater (a drinking water resource) and therefore can increase the likelihood of degredation of a compound in soil. The only previous study to assess sorption of cytostatic compounds to soil examined cyclophosphamide and ifosfamide, two closely related alkylating agents, in soil. CyTiS examined the sorption of cyclophosphamide, methotrexate, capecitabine, and doxorubicin, four cytostatic compounds which are widely used globally to treat a wide range of cancers and each of which represents diffferent classes of cytostatic compounds. Assessing different classes of compounds increases the applicability of the findings of this project to a wider number of chemotherapy drugs, which is importnant because the lack of previous research in this area means that there is not yet a framework for assessing which classes of compounds may pose a risk for transport and which may be sequestered in the soil. The second aim of this project was to examine the impact of cytostatic compounds on the health and diversity of microbial ecosystems in soil. No previous work has examined the effect of introducing cytostatic compounds to these communities. The importance of diverse soil communities in degrading all tyoes of organic material in waste streams makes it vital to understand how the introduciton of toxic pharmaceuticals, especially in the ever increasing amounts required for cancer treatment globally, may influence the health and productivity of these vital communities. CyTiS is the first project to have taken a preliminary survey of the potential impact that these compounds could be having, by examining the alterations to health and diversity of microbial communitites exposed to different classes of cytostatic compounds at both varied concentrations and over time.

Data: CORDIS, © European Union