Fungal Haze: How Wastewater Affects Our Waterways

In the Rio Grande river basin of New Mexico, treated wastewater plays a significant role in shaping the fungal populations in irrigation canals. This isn't just about water reuse. It's about understanding how these fungal communities can affect human health. There are two main ways this happens: through direct discharge of treated wastewater and through tiny fungal particles carried by the wind, known as bioaerosols. To figure this out, two sites were chosen. Site A had a wastewater treatment plant (WWTP) that discharged treated water into an irrigation canal. Site B, on the other hand, was right next to a WWTP but didn't receive any discharged water. This setup allowed researchers to study the effects of bioaerosols alone. The findings were clear. When the water flow was low and the wind was calm, the treated wastewater had a big impact on the types of fungi present in the canal. However, when the water flow was high, the differences along the canal were less noticeable. This suggests that the water flow can dilute the effects of the treated wastewater. At Site B, things were different. Under high wind conditions, the canal showed a high presence of potentially harmful fungi. These fungi, including Alternaria, Cladosporium, and Cryptococcus, came from the nearby WWTP and a livestock facility. This indicates that bioaerosols might spread fungal pathogens more widely than treated wastewater discharge alone. So, what does this all mean? It means that while treated wastewater can change the fungal makeup of irrigation canals, the wind-blown fungal particles might be an even bigger concern. This is something to think about, especially when it comes to public health and water management.