where multiple receptors are considered, such as exposure to wildlife and the soil
microbial community. This new knowledge will enable the development of thresholds for safe reuse of wastewater. Earthworms are key organisms to evaluate soil
quality and represent ideal sentinel organisms for assessing soil contamination, as
they are in contact with soil and soil solution, tend to migrate over only short
distances, and are widely distributed in soils around the globe. The possible role
of Lumbricus terrestris involvement on reducing pesticides and pharmaceuticals
toxicity has been demonstrated.
There are two general strategies for mitigation of PhACs in soil or their availability to crops. One is simply to decrease the concentrations of drugs before the
reclaimed water is irrigated into agricultural soil. Since conventional WWTPs cannot
remove most of the PhACs from domestic effluents, some advanced treatment
technologies (e.g., ozone and adsorption on activated carbon) have been strongly
recommended. However, these systems often require a high energy input and/or can
produce undesirable by-products. The development of additional effective and
low-cost treatments are needed to improve water quality. Constructed wetlands
(CWs), as an eco-sustainable wastewater treatment system, have been attracted
more attention especially in rural regions. However, the conventional CWs are
insufficient as they are unable to remove PhACs efficiently. There is therefore an
urgent need to develop more cost-effective CW systems to enhance the removal
efficiency of different PhACs classes. Promising technologies are the
microelectrolysis CWs, in which the electron transfer, microbial growth and metabolic enzyme activity, and biodegradation ability of microorganism can be promoted
or bioaugmented CWs with endophytic microorganisms which can also help in the
degradation of PhACs. The other strategy is to increase the degradation of PhACs in
soil by involving a broad range of agricultural practices that have the potential to
lower the amount of pharmaceuticals and/or their bioavailability but also by including possibility of on-site remediation. Amendment with fungi (e.g., Trichoderma
spp.) or with adapted soil microorganisms to pharmaceutical biodegradation might
be a wise choice for minimizing the level of PhACs in agricultural soil. The use of
earthworms to clean biosolids and manure (ex situ vermiremediation) and to reduce
pharmaceutical bioavailability to plants (in situ vermiremediation) has also been
suggested. The impact of earthworms on soil physicochemical and biological properties together with the tolerance of these organisms to PhACs makes these bioremediation strategies viable in soils receiving pharmaceutical-contaminated
amendments and water.
3 Presence, Uptake, and Metabolism of Drugs in Crops
From a quantitative perspective, it can be anticipated that the drug loads reaching
wastewater treatment plants will increase in the near future owing to the aging
population, demographic growth, expanding lifestyle diseases particularly in Western countries, and those adopting their bad habits while at the same time climate
Conclusions and Future Perspectives
527
microbial community. This new knowledge will enable the development of thresholds for safe reuse of wastewater. Earthworms are key organisms to evaluate soil
quality and represent ideal sentinel organisms for assessing soil contamination, as
they are in contact with soil and soil solution, tend to migrate over only short
distances, and are widely distributed in soils around the globe. The possible role
of Lumbricus terrestris involvement on reducing pesticides and pharmaceuticals
toxicity has been demonstrated.
There are two general strategies for mitigation of PhACs in soil or their availability to crops. One is simply to decrease the concentrations of drugs before the
reclaimed water is irrigated into agricultural soil. Since conventional WWTPs cannot
remove most of the PhACs from domestic effluents, some advanced treatment
technologies (e.g., ozone and adsorption on activated carbon) have been strongly
recommended. However, these systems often require a high energy input and/or can
produce undesirable by-products. The development of additional effective and
low-cost treatments are needed to improve water quality. Constructed wetlands
(CWs), as an eco-sustainable wastewater treatment system, have been attracted
more attention especially in rural regions. However, the conventional CWs are
insufficient as they are unable to remove PhACs efficiently. There is therefore an
urgent need to develop more cost-effective CW systems to enhance the removal
efficiency of different PhACs classes. Promising technologies are the
microelectrolysis CWs, in which the electron transfer, microbial growth and metabolic enzyme activity, and biodegradation ability of microorganism can be promoted
or bioaugmented CWs with endophytic microorganisms which can also help in the
degradation of PhACs. The other strategy is to increase the degradation of PhACs in
soil by involving a broad range of agricultural practices that have the potential to
lower the amount of pharmaceuticals and/or their bioavailability but also by including possibility of on-site remediation. Amendment with fungi (e.g., Trichoderma
spp.) or with adapted soil microorganisms to pharmaceutical biodegradation might
be a wise choice for minimizing the level of PhACs in agricultural soil. The use of
earthworms to clean biosolids and manure (ex situ vermiremediation) and to reduce
pharmaceutical bioavailability to plants (in situ vermiremediation) has also been
suggested. The impact of earthworms on soil physicochemical and biological properties together with the tolerance of these organisms to PhACs makes these bioremediation strategies viable in soils receiving pharmaceutical-contaminated
amendments and water.
3 Presence, Uptake, and Metabolism of Drugs in Crops
From a quantitative perspective, it can be anticipated that the drug loads reaching
wastewater treatment plants will increase in the near future owing to the aging
population, demographic growth, expanding lifestyle diseases particularly in Western countries, and those adopting their bad habits while at the same time climate
Conclusions and Future Perspectives
527