A common challenge when trying to monitor micropollutants in wastewater and waterways is that they are usually present at very low concentrations and therefore, may not be detected by standard analytical methods. Similarly, if individual water samples are taken, they only reflect what is present at that point in time, again increasing the likelihood of missing, or not detecting all micropollutants present at other times. This is especially important when trying to monitor sporadic events, such as sewer spills.
Here we present the findings from a sampling program that was undertaken using passive samplers, to continuously accumulate water soluble organic contaminants over a 4-week period, including pesticides, pharmaceuticals and personal care products. The samplers were deployed in surface waters at >50 sites, including areas known or suspected to be impacted by septic tank leaks, or those exposed to treated or untreated sewer discharges.
A total of 215 different compounds were screened for and 56 different compounds were detected. The most frequently detected compounds were herbicides (simazine, diuron, atrazine and metolachlor), fungicides (carbendazim, propiconazole and tebuconazole), insecticides (fipronil and imidacloprid) and pharmaceuticals (paracetamol, carbamazepine, erythromycin and sulphapyridine). The results will be discussed in relation to types of wastewater inputs, catchment landuse and waterway values. An evidence-based understanding of wastewater-related contaminants and how these impact ecological values will enable a more structured and strategic process for prioritising the investigation and management of particular wastewater sources to waterways.