Metals, nutrients and total suspended solids discharged during different flow conditions in highly urbanised catchments

Abstract

Stormwater discharged from highly urbanised catchments on the southern shore of Sydney estuary, Australia, has been identified as the primary source of contaminants responsible for ecological degradation and reduction in recreational value of the waterway. Effective management of this pollution requires knowledge of contaminant loads associated with various stormwater flow conditions in three highly urbanised catchments in Sydney estuary catchment. The majority (>90%) of metal (Cu, Pb and Zn) and total suspended solid annual loads were contributed during high-flow conditions (>50 mm rainfall day(t1)), whereas ≤55% of TN and ≤21% of total phosphorus were contributed to annual loading by dry weather base-flow conditions. All flow conditions posed an in-stream ecological threat because contaminant concentrations exceeded water quality guidelines for all analytes measured, except Pb. Irregular, temporal variability in contaminant concentrations associated with base-flow (within day and amongst days), high-flow (amongst events) and irregular discharges indicated that contaminant contributions in stormwater were strongly controlled by human activity in the three catchments. Significant variation in contaminant concentrations under all flow conditions revealed unique chemical signatures for each catchment despite similarities in land uses, location and geology amongst catchments. These characteristics indicate that assessment and management of stormwater pollution needs to be conducted on an individual-catchment basis for highly urbanised regions of Sydney estuary catchment.

Community structure and distribution of planktonic ammonia-oxidizing archaea and bacteria in the Dongjiang River, China

“…The TSS is a combination of organic and inorganic particles suspended in the water column, and water current is the main driving force of suspended solids. Changes associated with urbanization, such as increasing industrial land use, increase the availability of TSS and nutrients through surface runoff [79], which suggests that terrestrial rainwater runoff might affect river basins and influence the distribution patterns of AOB. Overall, the changes in AOB community structure dynamically respond to changing water properties.…”

Drivers of change in estuarine‐coastal ecosystems: Discoveries from four decades of study in San Francisco Bay

“…In some estuaries, such as those of the northeast United States [ Whitall et al , 2007], sewage input remains the largest source of nitrogen, reflecting the design of secondary sewage treatment to reduce BOD (not nutrients) in effluent. For others, such as Australia's Sydney estuary, storm water runoff from urban watersheds is the primary source of nutrients and metals [ Beck and Birch , 2012]. The largest sources of nitrogen to most estuaries, however, are the diffuse nonpoint sources generated by agriculture and fossil fuel combustion [ Howarth et al , 2002].…”

Effect of antimicrobials, salinity, and contamination by air on bacterial and fungal growth in cyprid cultures of Amphibalanus improvisus

“…Hypothesis (ii) can be explained by the occurrence of bacterial resistance as a result of domestic and industrial discharges in the Patos Lagoon estuary. Estuaries, including the Patos Lagoon, are among the most urbanized coastal ecosystems, constantly suffering from anthropogenic impacts including the discharge of domestic, industrial, and hospital waste which often contain chemical substances (through the disposal of animal feces, medical wastes, and direct feeding), such as antimicrobials (Beck & Birch, ; Jeffries et al, ; Kümmerer, ; Kümmerer, ; Sun, Dafforn, Brown, & Johnston, ). According to Kemper (), most antibiotics are water‐soluble, and therefore, up to 90% of dosed antibiotics can be excreted.…”