Sulfamethoxazole

Detailed information

Fass environmental information

Fass environmental information for Bactrim (sulfamethoxazole, trimethoprim) from Roche (downloaded 2019-06-14).

Hazard

Persistence: "Biotic Degradation:
Ready biodegradability:
4% after 28 days of incubation BOD/ThOD (OECD 301 D)
13% after 28 days of incubation BOD/ThOD (OECD 301 D with co-metabolism)
Inherent biodegradability:
-10% after 28 days of incubation CO2/TOC (OECD 302 B)
13% after 28 days of incubation DOC (OECD 302 B)
0% after 28 days of incubation DOC (OECD 302 B).

Sulfamethoxazole is neither readily, nor inherently biodegradable. This justifies the phrase 'Sulfamethoxazole is potentially persistent.'"

Bioaccumulation: Log K_OW 0.89 experimental, method unknown. Log K_OW 0.48 QSAR. Sulfamethoxazole has low potential for bioaccumulation (log K_OW <4).

Toxicity: There are data for 3 trophic levels, most sensitive Cyanobacteria (Synechococcus leopoliensis) NOEC 96 h = 0.0059 mg/l (method not specified)".

Risk

PEC/PNEC is based on sales data in Sweden in year 2017. PEC/PNEC = 0.440 which gives the risk low.

Report Goodpoint

Good margin between occurrences in Swedish waters and concentration for effect. Low risk for selection of antibiotic resistant bacteria.

Pharmaceutial residues in the aquatic environment

Sulfamethoxazole has been detected in treated wastewater in Region Stockholm and in the aquatic environment elsewhere in Sweden.

EU water legislation

Sulfamethoxazole is monitored within the framework of EU water legislation. "Substances for which doubt exists about their toxicity, or for which the sensitivity, reliability or comparability of the available monitoring methods are not adequate, should not be included in the watch list. The sulfonamide antibiotic sulfamethoxazole and the diaminopyrimidine antibiotic trimethoprim, the antidepressant venlafaxine and its metabolite O-desmethylvenlafaxine, a group of three azole pharmaceuticals (clotrimazole, fluconazole and miconazole) ... The inclusion of the various pharmaceuticals is consistent with the EU Strategic Approach to Pharmaceuticals in the Environment, and the inclusion of the two antibiotics is also consistent with the European One Health Action Plan against Antimicrobial Resistance (AMR), which supports the use of the watch list to ‘improve knowledge of the occurrence and spread of antimicrobials in the environment’."

In general

For antibiotics in general, it is recommended that these drugs are used as restrictively as possible without risking the patient's health.