Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2014 Jul 15;487(100):642–650. doi: 10.1016/j.scitotenv.2014.02.101

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2014 The Authors

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

PMC Copyright notice

Fig. 1 — Directed acyclic graph for ‘back-calculation’ approach (single metabolite).

Consumption_d = cocaine consumption per 1000 people on day d (mg); Load_d = load of metabolite entering the wastewater system on day d (grammes); Population = size of the population served by the WWTP (millions); Concentration_d = concentration of metabolite in sample of wastewater on day d (ng/l); Flow_d = total volume of flow to the wastewater influent on day d (millions of litres); Stability = percentage change in concentration of metabolite in wastewater in the conditions relevant to the study; Excretion = proportion of consumed cocaine that is excreted as the metabolite; MWm = molecular weight of metabolite; MWc = molecular weight of cocaine; ps = proportion of all cocaine mass that is smoked as free base, es = proportion of a dose of cocaine smoked as free base that is excreted as the metabolite; en = proportion of a dose of cocaine consumed by nasal insufflation that is excreted as the metabolite.