Source Apportionment, Hydrodynamic Influence, and Environmental Stress of Pharmaceuticals in a Microtidal Estuary with Multiple Outlets in South China

Abstract

Pharmaceutical residues in the environment are of great concern as ubiquitous emerging contaminants. This study investigated the presence of 40 pharmaceuticals in water and sediment of the Pearl River Estuary (PRE) in the wet season of 2020. Among psychiatric drugs, only diazepam was found in water samples while six of them were detected in the sediment. The Σantibiotics levels ranged from 6.18 to 35.9 ng/L and 2.63 to 140 ng/g dry weight in water and sediment samples, respectively. Fluoroquinolones and tetracyclines were found well settling in the outlet sediment, while sulfonamides could be released from disturbed sediment under stronger tidal wash-out conditions. After entering the marine waters, pharmaceuticals tended to deposit at the PRE mouth by the influence of the plume bulge and onshore invasion of deep shelf waters. Low ecological risks to the aquatic organisms and of causing antimicrobial resistance were identified. Likewise, hydrological modeling results revealed insignificant risks: erythromycin-H 2 O and sulfamethoxazole discharged through the outlets constituted 30.8% and 6.74% of their environmental capacity, respectively. Source apportionment revealed that pharmaceutical discharges through the Humen and Yamen outlets were predominantly of animal origin. Overall, our findings provide strategic insights on environmental regulations to further minimize the environmental stress of pharmaceuticals in the PRE.

Anthropogenic Impacts on Organophosphate Ester Loads to an Urban Estuary in South China

“…With high OPE concentrations and large river discharge, Humen dominated the riverine inputs of OPEs by contributing 5940 and 14,500 kg to the PRE in the dry and wet seasons, respectively. This result is consistent with previous reports on antibiotics and phthalates in the same region, ,, indicating that Humen is the major contributor to many emerging contaminants. The riverine inputs of OPEs from the eastern riverine outlets were greater than those from the western ones, which accounted for 78.5% and 89.4% of total input during the dry and wet seasons, respectively.…”

“…In recent years, about 2500 new chemicals have been reviewed by the government and then introduced into the market in the United States annually . Many chemicals as additives can be readily released into the environment during their lifecycles and carried to rivers and then estuaries, potentially endangering the aquatic ecosystems. − Notably, estuaries serve as crucial ecological habitats and fishery areas as well as buffers between the land and sea. Understanding anthropogenic impacts on chemical contamination in estuarine ecosystems is, therefore, indispensable for supporting their environmental management and sustainable development.…”

Widespread Occurrence and Transport of p-Phenylenediamines and Their Quinones in Sediments across Urban Rivers, Estuaries, Coasts, and Deep-Sea Regions

“…The urban rivers of the PRD and the PRE are the source and near-source regions for PPDs and PPD-Qs, while the coastal and deep-sea regions away from the source and near-source regions are considered to be less affected by direct anthropogenic inputs but more affected by oceanic conditions such as coastal and oceanic currents. The lack of significant correlations between the concentrations of PPDs and PPD-Qs in the coastal and deep-sea regions may be ascribed to multiple factors such as hydrodynamic conditions 57 as well as differential transport and deposition behaviors in the marine environment that could confound these observations. The potential transformation of PPDs to other chemicals rather than PPD-Qs under oceanic conditions might be another plausible factor.…”

Phytoplankton Biological Pump Controls the Spatiotemporal Bioaccumulation and Trophic Transfer of Antibiotics in a Large Subtropical River

“…4 In the Pearl River Estuary, a hydrological model has revealed that the discharge of erythromycin-H 2 O and sulfamethoxazole through outlets accounts for 30.8 and 6.74% of their environmental capacity, respectively. 5 Humans can be exposed to antibiotics through seafood consumption, thus prompting the need for systemic investigation of bioaccumulation, hazard evaluation, and risk assessments in aquatic organisms. 6−9 Once in the water column, the biological pump and degradation largely determine the fate of organic pollutants.…”

“…It has been established that the consistent dissemination of antibiotics through aquaculture (mariculture) activities, riverine transport, land-based sources, and coastal seawater serves as a primary contributor to the ubiquitous contamination of antibiotics in the environment, characterized by a “pseudo-persistence”. − Antibiotics have been shown to exhibit rapid toxicity on nontarget biota, primarily at the ng mL –1 level, and may lead to the development of antimicrobial resistance (AMR) . In the Pearl River Estuary, a hydrological model has revealed that the discharge of erythromycin-H 2 O and sulfamethoxazole through outlets accounts for 30.8 and 6.74% of their environmental capacity, respectively . Humans can be exposed to antibiotics through seafood consumption, thus prompting the need for systemic investigation of bioaccumulation, hazard evaluation, and risk assessments in aquatic organisms. − Once in the water column, the biological pump and degradation largely determine the fate of organic pollutants. , Previous studies have demonstrated that the phytoplankton biological pump plays an important role in regulation of water column mass balance and burial of antibiotics in eutrophic ecosystems, which could further affect the fate and trophic transfer behaviors of antibiotics in food webs. , Consistently higher bioaccumulation factors (BAFs) of other organic pollutants, such as perfluorooctanoate (PFOA), in oceanic plankton have been found in large oligotrophic global oceans .…”