TY  - JOUR
AU  - Devault, D.A.
AU  - Lévi, Y.
AU  - Karolak, S.
PY  - 2017//
TI  - Applying sewage epidemiology approach to estimate illicit drug consumption in a tropical context: Bias related to sewage temperature and pH
T2  - Science of the Total Environment
JO  - Science of the Total Environment
SP  - 252
EP  - 258
VL  - 584-585
KW  - Cannabis
KW  - Degradation
KW  - H2s
KW  - Half-life
KW  - Illicit drugs
KW  - Wastewater
N2  - Illicit drug consumption can be estimated from drug target residue (DTR) in wastewater, with the reliability of results being partly linked to DTR stability in the sewage network. However, wastewater temperature and pH drive the stability of molecules and, in this context, tropical conditions must be studied to specify the impact of residence time in the sewage network on DTR degradation. Warmth enhances biotic and abiotic processes such as degradation, leading to a decrease in oxygen content, and consequently, early diagenesis conditions in wastewater. In this study, we conduct laboratory studies under acidic pH and high temperature (30 °C) conditions to determine the degradation half-lives of cocaine (COC), tetrahydrocannabinol, and heroine targets, allowing COC/benzoylecgonine (BZE) ratio variations to be predicted in sewage networks. A rapid COC degradation is observed, as already reported in the literature but without a short-term significant difference between 20 °C and 30 °C. Acidic pH seems to prevent degradation. Thus, theoretically, the use of COC as DTR is only reliable in acidic conditions, with the decrease in COC concentration being 6% at 8 h, but over 40% in other conditions. By contrast, the use of BZE as DTR to estimate COC consumption, which is performed in practice, can be undertaken with the same back-calculation equation as used in temperate countries. However, 11-nor-delta-9-carboxytetrahydrocannabinol stability is more influenced by high temperature: concentration levels after 24 h are 20% lower at 30 °C than at 20 °C, corresponding to a 20% and 40% decrease, respectively. Based on a mean residence time of 8 h, underestimated cannabis consumption is close to 15% in tropical contexts, which is double that of temperate areas. © 2017 Elsevier B.V.
UR  - https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012065422&doi=10.1016%2fj.scitotenv.2017.01.114&partnerID=40&md5=6a66621b747140a909b4d59277147cb7
UR  - http://dx.doi.org/10.1016/j.scitotenv.2017.01.114
N1  - Export Date: 8 March 2017
ID  - Devault_etal2017
ER  -