# Biobio Sentinel: Two years of illicit drug surveillance in South-Central Chile. > **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637) > **Publisher:** CED Clinic (https://cedclinic.com) > **Canonical URL:** https://cedclinic.com/wastewater-based-epidemiology-cannabis-trends-biobio/ > **Published:** 2026-03-24T18:08:11-04:00 | **Last Modified / Clinically Audited:** 2026-09-28T10:40:21-04:00 > **Clinical Summary:** Wastewater-based epidemiology reveals cannabis consumption trends and illicit drug surveillance in South-Central Chile's Biobio Region over two years. --- CED Clinical Relevance  #56Monitored Relevance  Early-stage or contextual signal requiring further evidence before action. 🔬 Evidence Watch  |  CED Clinic CannabisEpidemiologySurveillancePopulation HealthThc Journal Journal of hazardous materials Study Type Clinical Study Population Human participants Why This Matters This wastewater-based epidemiology study provides unprecedented population-level surveillance data on cannabis consumption patterns, offering clinicians objective community-wide trends that complement individual patient reports. Understanding regional consumption patterns helps inform clinical decision-making and [public health](https://cedclinic.com/cannabis-mold-contamination-risks-recall-safety/) approaches to [cannabis use](https://cedclinic.com/cannabis-cardiovascular-health-insights-2024/) disorders. Clinical Summary This two-year surveillance study analyzed wastewater from 33 treatment plants across Chile’s Biobío Region, tracking metabolites of cocaine, cannabis, and ketamine in over 3,000 samples from September 2022 to August 2024. The study revealed a dramatic 90% decline in cannabis consumption alongside a tenfold increase in cocaine use, while ketamine emerged as a new detectable substance. The wastewater-based epidemiology methodology provides population-normalized consumption estimates independent of self-reporting bias. This approach offers valuable community-level surveillance capabilities, though it cannot distinguish between medical and [recreational cannabis use](https://cedclinic.com/sex-differences-cannabis-stress-reactivity-oxytocin/) or provide individual consumption data. Dr. Caplan’s Take “While this surveillance method cannot differentiate medical from [recreational cannabis use](https://cedclinic.com/sex-differences-cannabis-stress-reactivity-oxytocin/), the dramatic consumption shifts it reveals underscore how quickly substance use patterns can change at the population level. This reinforces my clinical experience that staying current with local consumption trends helps inform more relevant patient conversations about [cannabis use](https://cedclinic.com/cannabis-cardiovascular-health-insights-2024/) patterns and risks.” Clinical Perspective 🧠 Clinicians should view wastewater epidemiology as complementary surveillance data that provides community context for individual patient assessments. This methodology offers objective population trends that can inform clinical awareness of emerging substances and changing use patterns, though individual [patient care](https://cedclinic.com/cannabis-cardiovascular-risk-impact/) decisions should remain based on direct clinical evaluation and patient-reported outcomes. 💬 Join the Conversation Have a question about how this applies to your situation? [Ask Dr. Caplan →](https://benjamincaplan.com/ask-dr-caplan) Want to discuss this topic with other patients and caregivers? [Join the forum discussion →](https://cedclinic.com/interact/discussion-forums/forum/cannabis-industry/) Have thoughts on this? Share it: [𝕏 Share on X](https://twitter.com/intent/tweet?text=Just%20read%20this%20on%20CEDclinic.com%3A%20Biobio%20Sentinel%3A%20Two%20years%20of%20illicit%20drug%20surveillance%20in%20South-Central%20Chile.%20%40drcaplan&url=https%3A//pubmed.ncbi.nlm.nih.gov/41546897/)[in Share on LinkedIn](https://www.linkedin.com/sharing/share-offsite/?url=https%3A//pubmed.ncbi.nlm.nih.gov/41546897/)[🦥 Share on BlueSky](https://bsky.app/intent/compose?text=Just%20read%20this%3A%20Biobio%20Sentinel%3A%20Two%20years%20of%20illicit%20drug%20surveillance%20in%20South-Central%20Chile.%20--%20via%20%40drcaplan.bsky.social%20https%3A//pubmed.ncbi.nlm.nih.gov/41546897/)[📷 Follow on Instagram](https://www.instagram.com/drbenjamincaplan/)[📝 Read more on Substack](https://substack.com/@doctorapproved)[🔔 Subscribe via RSS](https://cedclinic.com/category/cannabis-news/feed/) 📰 Source: [https://pubmed.ncbi.nlm.nih.gov/41546897/](https://pubmed.ncbi.nlm.nih.gov/41546897/) Table of Contents - [FAQ](#FAQ)[What does this study reveal about cannabis use trends in South-Central Chile?](#What_does_this_study_reveal_about_cannabis_use_trends_in_South-Central_Chile) - [How reliable is wastewater-based epidemiology for monitoring cannabis use compared to traditional surveys?](#How_reliable_is_wastewater-based_epidemiology_for_monitoring_cannabis_use_compared_to_traditional_surveys) - [What clinical implications should healthcare providers consider given these cannabis consumption trends?](#What_clinical_implications_should_healthcare_providers_consider_given_these_cannabis_consumption_trends) - [Can wastewater surveillance help predict cannabis-related health outcomes in communities?](#Can_wastewater_surveillance_help_predict_cannabis-related_health_outcomes_in_communities) - [How might the concurrent rise in cocaine and ketamine use affect cannabis treatment approaches?](#How_might_the_concurrent_rise_in_cocaine_and_ketamine_use_affect_cannabis_treatment_approaches) - [Related](#Related) ## FAQ #### What does this study reveal about cannabis use trends in South-Central Chile? The study found that cannabis consumption declined by over 90% in the Biobío Region between September 2022 and August 2024, as measured through wastewater analysis of THC metabolites. This dramatic decrease contrasts sharply with a tenfold increase in cocaine use during the same period, suggesting significant shifts in regional drug consumption patterns. #### How reliable is wastewater-based epidemiology for monitoring cannabis use compared to traditional surveys? Wastewater-based epidemiology (WBE) provides objective, population-level data by detecting actual drug metabolites in sewage, eliminating self-reporting bias common in surveys. This method offers real-time monitoring of entire communities through analysis of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol, the primary THC metabolite, making it a valuable complement to traditional surveillance methods. #### What clinical implications should healthcare providers consider given these cannabis consumption trends? The 90% decline in cannabis use may indicate shifting substance use patterns that could affect treatment planning and resource allocation. Clinicians should remain aware that population-level trends may not reflect individual patient patterns and should continue comprehensive substance use assessments regardless of regional surveillance data. #### Can wastewater surveillance help predict cannabis-related health outcomes in communities? While this study demonstrates WBE’s capability to track consumption trends, it represents early-stage evidence requiring further research to establish correlations with clinical outcomes. The two-year dataset provides baseline surveillance data but additional studies are needed to determine predictive value for cannabis-related health impacts. #### How might the concurrent rise in cocaine and ketamine use affect cannabis treatment approaches? The emergence of ketamine and dramatic increase in cocaine use alongside declining cannabis consumption suggests evolving polysubstance use patterns in the region. Healthcare providers should consider these shifting trends when developing treatment protocols and remain vigilant for new [drug interaction](https://cedclinic.com/glp-1-addiction-risk-reduction-benefits/) profiles and co-occurring substance use disorders. {“@context”: “https://schema.org”, “@type”: “ScholarlyArticle”, “headline”: “Biobio Sentinel: Two years of illicit drug surveillance in South-Central Chile.”, “url”: “https://pubmed.ncbi.nlm.nih.gov/41546897/”, “about”: “journal hazardous materials clinical study biobio”, “isPartOf”: “Journal of hazardous materials”} [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Physician-Led, Whole-Person Care A doctor who takes the time to truly understand you. Personal care that starts with listening and is guided by experience and ingenuity. Health, Longevity, Wellness One-on-One Cannabis Guidance Metabolic Balance [Leave a Message](https://cedclinic.com/contact/) [Metabolic Care](https://cedclinic.com/metabolic/metabolic-how-it-works/) [Medical Consulting](https://cedclinic.com/book/) [Cannabis Care](https://cedclinic.com/book/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) RELATED READING AT CED CLINIC Continue exploring the evidence [Biobio Sentinel: Two years of illicit drug surveillance in South-Central Chile.](https://cedclinic.com/wastewater-cannabis-surveillance-population-drug-trends-chile/) Explore detailed findings from the Biobio Sentinel study on illicit drug trends using wastewater surveillance in Chile. [Read More](https://cedclinic.com/wastewater-cannabis-surveillance-population-drug-trends-chile/) [Substance Use and Suicide Attempts in Adolescents: A Comparative Analysis of Clinical and Psychosocial Risk Factors.](https://cedclinic.com/adolescent-substance-use-suicide-risk-analysis/) Review clinical and psychosocial risk factors linking substance use and suicide attempts among adolescents. [Explore Study](https://cedclinic.com/adolescent-substance-use-suicide-risk-analysis/) [Lifestyle and Behavioral Enhancements of Sleep: A Review.](https://cedclinic.com/sleep-hygiene-cbt-i-lifestyle-enhancements/) Understand lifestyle and behavioral strategies to improve sleep quality and their clinical relevance. [Learn More](https://cedclinic.com/sleep-hygiene-cbt-i-lifestyle-enhancements/) ### Related --- ### Verification & Medical Governance - **Lead Clinical Author:** Benjamin Caplan, MD - **Credentials:** Board Certified in Family Medicine (ABFM), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House). - **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`). - **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/). - **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637). - **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).