The occurrence of opioid compounds in wastewater treatment plants and their receiving water bodies in Gauteng province, South Africa.

The continuous influx of opioid compounds into aquatic environments has become an increasing and persistent concern, due to their extensive use. This is especially alarming as wastewater treatment plants (WWTPs) are unable to completely remove them. Despite the reported health concerns, the occurrence of opioid compounds in the environment has not received much attention. The present study investigates the occurrence of 19 opioids in four WWTPs and their respective receiving water bodies. All wastewater samples revealed opioids at concentration ranging from ng/L to µg/L with most influents having higher concentrations than effluents. WWTPs appeared to perform poorly (p > 0.05 between influents and effluents), and were unable to remove some opioids including Methadone (-27.3%) from the Leeuwkuil WWTP, Codeine (-21.7%) and Thebaine (-3.77%) from the Sandspruit WWTP, and Hydrocodone (-1.06%) from the Meyerton WWTP, respectively. Samples collected from the Leeuwkuil WWTP were the most contaminated, with eighteen out of nineteen opioid analogues exceeding 1 µg/L. Upstream surface water contained less opioids (most < LOQ) than downstream (p < 0.05), with Hydrocodone, Oxycodone, Hydromorphone, Fentanyl, Ketamine and Dihydrocodeine not detected. The occurrence of high concentrations of opioid analogues in downstream surface water (298 ng/L -10.8 µg/L for Klip River, 4.49 ng/L -13.1 µg/L for Vaal River, 70.5 ng/L -10.0 µg/L for Soutspruit River and 8.0 ng/L - 2.43 µg/L for Sun Spruit River) was directly linked to their mass loads in the respective wastewater effluent samples.

Acid Mine Drainage as Habitats for Distinct Microbiomes: Current Knowledge in the Era of Molecular and Omic Technologies.

The last decade has witnessed growth in scientific interest towards studying the biodiversity and ecology in extreme environments. Acid Mine Drainage (AMD), formed through the bio-oxidation of metal sulphides, is a typical extreme environment that is inhospitable to most life forms. Through the application of traditional culture-based molecular techniques, it has been established that AMD is home to a low diversity, specialized and novel microbial community that plays a critical role in its formation. Intensive efforts have been channeled towards understanding the ecology, microbial biodiversity, processes and metabolic networks within these simple ecosystems. Molecular techniques using high-throughput next-generation sequencing platforms have taken center stage in discerning both the taxonomic and functional diversity in these microbial communities. Recently developed post-genomic approaches as well have been particularly instrumental in deciphering in situ interactions within microbial communities and the environment. In this review, a critical synopsis of the current applications of advanced molecular techniques in probing microbial and functional diversity in AMD environments is presented.