Comparison of analytical and theoretical pharmaceutical concentrations in human urine in Germany.

Urine is considered as a valuable plant fertiliser due to its high nutrient content. However, urine also contains pharmaceuticals. Currently, little is known regarding expected pharmaceutical concentrations in urine and the resulting risks. Through series of analyses in Hamburg and Berlin and results from the development of a concentration prediction model this knowledge gap was intended to be filled. To which extent the theoretical calculations can substitute analyses of pharmaceuticals was also tested. Results showed that the model fits well for bezafibrate, carbamazepine, diclofenac, ibuprofen, phenazone, and pentoxifylline. In Hamburg an R(2) value of 0.98 and in Berlin of 0.90 was achieved for correlations between predicted and analysed concentrations. Additionally, it was shown that a sufficient number of people discharging their urine to the respective collection system are important to allow for reasonable predictions via calculation. Also, comparisons of predicted pharmaceutical concentrations to those determined in other projects showed good correlations. Overall, it can be concluded that in any case the calculated concentrations exceed the measured ones and are therefore conservative. This overestimation can be explained by several factors discussed in this article.

A comparison of human pharmaceutical concentrations in raw municipal wastewater and yellowwater.

Currently, many articles report on pharmaceutical residues detected in various compartments of the environment. A major pathway into the aquatic environment is municipal wastewater. This article discusses the relevance of yellowwater (urine) as pharmaceutical source within this wastewater stream. Literature data about concentrations of 28 pharmaceutical residues detected in raw wastewater are compared to their theoretically calculated concentrations in urine. The study shows that these pharmaceuticals and their metabolites are excreted predominantly via urine although some substances show reasonable excretion via faeces. It is demonstrated that the influence of pharmacokinetic activities is one important issue affecting the presence of pharmaceuticals in the aquatic environment. Nevertheless, only a weak correlation between concentrations of pharmaceuticals calculated in yellowwater and analysed in raw wastewater was observed. This is due to environmental effects taking place between the excretion of urine and the entrance of sewerage into the wastewater treatment plant. The data show that urine separation and separate handling/treatment of this wastewater stream represents a promising approach to protect the aquatic environment safely from human pharmaceuticals.

Impact assessment of emission management strategies of the pharmaceuticals Metformin and Metoprolol to the aquatic environment using Bayesian networks.

The issue of pharmaceuticals in the environment has caused increasing concern in the recent years and various strategies have been proposed to tackle this problem. This work describes a Bayesian network (BN)-based socio-ecological impact assessment of a set of measures aimed at reducing the entry of pharmaceuticals in the aquatic environment. The measures investigated were selected across three sectors: public health market, environmental politics and drug design innovation. The BN model was developed for two drugs, Metformin and Metoprolol, and it models the distribution of the Predicted Environmental Concentration (PEC) values as a function of different measures. Results show that the sensitivity of the PEC for the two drugs to the measures investigated reflects the distinct drug characteristics, suggesting that in order to ensure the successful reduction of a broad range of substances, a spectrum of measures targeting the entire lifecycle of a pharmaceutical should be implemented. Furthermore, evaluation of two scenarios reflecting different emission management strategies highlights that the integrated implementation of a comprehensive set of measures across the three sectors results in a more extensive reduction of the contamination. Finally, the BN provides an initial forecasting tool to model the PEC of a drug as a function of a combination of measures in a context-specific manner and possible adaptations of the model are proposed.

Ryegrass uptake of carbamazepine and ibuprofen applied by urine fertilization.

Human urine is a potential alternative fertilizer for agriculture. However, its usage is associated with a risk of spreading pharmaceutical residues to fields. The individual and combined behavior of carbamazepine and ibuprofen was investigated by GC/MS analysis in a greenhouse experiment using ryegrass fertilized with pharmaceutical-spiked urine. Only carbamazepine could be detected in soil, roots, and aerial plant parts. Fifty-three per cent of carbamazepine originally present in the urine was recovered in soil samples taken after three months. Additionally, 34% of carbamazepine was found in aerial plant parts and 0.3% in roots. Model calculations showed that neither roots nor Casparian strip posed a considerable barrier to uptake. Carbamazepine transport was clearly driven by transpiration. Ibuprofen was not detected in the soil or in any plant parts after three months. This was assumed to be due to biodegradation of ibuprofen. Carbamazepine and ibuprofen, singly or in combination, did not adversely affect the growth of ryegrass.

Fertiliser products from new sanitation systems: their potential values and risks.

The plant nutrients consumed in human society today are lost through the established wastewater treatment systems in industrialised countries as well as via insufficient or non-existent handling of sewage in the developing world. New sanitation systems have been designated to overcome this failure. The source separated wastewater streams collected within these systems contain a high nutrient content, and can be used as fertiliser as well as soil conditioner after appropriate storage and/or treatment. Application in agriculture with existing techniques is feasible. However, pathogens and pharmaceuticals contained in these fertiliser types are a potential hazard. Nevertheless, storage and appropriate treatment can minimise the risks. The products deriving from these systems have a high potential to preserve available plant nutrient resources and deficiencies in agriculture as well as being able to substitute synthetic plant nutrients and at the same time prevent unwanted environmental nutrient over-enrichment.