Monitoring of carbamazepine concentrations in wastewater and groundwater to quantify sewer leakage.

Monitoring of carbamazepine concentrations in wastewater and groundwater enables us to identify and quantify sewer exfiltration. The antiepileptic drug carbamazepine is hardly removed in wastewater treatment plants and not or just slightly attenuated during bank infiltration and subsoil flow. Concentrations in wastewater are generally 1000 times higher than the limit of quantification. In contrast to . many other wastewater tracers carbamazepine is discharged to the environment only via domestic wastewater. The results from this study carried out in Linz, Austria indicate an average exfiltration rate of 1%, expressed as percentage of the dry weather flow that is lost to the groundwater on the city-wide scale. This rate is lower than sewage losses reported in most other studies which attempted to quantify exfiltration on the basis of groundwater pollution. However, it was also possible to identify one area with significantly higher sewage losses. This method seems to be very suitable for the verification of leakage models used to assess sewer exfiltration on a regional scale.

Quantification of sewer exfiltration using the anti-epileptic drug carbamazepine as marker species for wastewater.

The anti-epileptic drug carbamazepine was used as marker species in wastewater to identify and quantify sewer exfiltration. In several studies carbamazepine turned out to be hardly removed in wastewater treatment and not or just slightly attenuated during bank infiltration. Concentrations in wastewater are generally 1000 times higher than the limit of quantification. In contrast to many other marker species a "young" drug as carbamazepine is discharged to the environment only by wastewater. The results from this study carried out in Linz, Austria indicate an average exfiltration rate, expressed as percentage of the dry weather flow that is lost on the city-wide scale, of 1%. This rate is lower than sewage losses reported in most other studies which attempted to quantify exfiltration on the basis of groundwater pollution. However, it was also possible to identify one area with significant higher sewage losses.

Chemical changes during the early phase of in vitro oxidative damage to human LDL.

Much of the oxidative damage to human LDL in vivo may lead to only minimal changes in the chemical properties of the LDL. Therefore, chemical changes were evaluated during the initial 3 hours of oxidative attack on human LDL with 5 microM Cu. HPLC analyses were calibrated with a conjugated-diene internal standard. Cholesterol-linoleate-hydroperoxide (Chol-18:2-OOH) accumulated much more rapidly than alpha-tocopherol was lost. Although large amounts of cholesterol arachidonate were destroyed, diene-containing oxidation products of this lipid were not identified by HPLC analysis. Phosphatidyl-choline-hydroperoxides accumulated much more slowly than chol-18:2-OOH. beta-carotene was oxidized relatively slowly, but lycopene was destroyed almost as fast as alpha-tocopherol. The preferential accumulation of chol-18:2-OOH is consistent with a model in which alpha-tocopherol is localized to the surface of the LDL particle, providing minimal protection to hydrophobic components in the core of the LDL.