Emerging pharmaceutical contaminants in key aquatic environments of the Philippines

These pollutants can bioaccumulate in the food chain, contribute to shifts in mesocosm communities, and have transcription impacts in microbes. The United States Environmental Protection Agency (US EPA) and the European Union consider PPCPs as contaminants of emerging concern (CECs), which are low-concentration pollutants detected in surface waters for which no standard concentration has been established. Technological advancements have allowed detection of contaminants to the nanogram level, and PPCPs have been detected in wastewater, groundwater, submarine groundwater discharge (SGD), river waters, and coastal waters around the globe. Caffeine and pharmaceutical residues such as carbamazepine, sulfapyridine, sulfamethoxazole, ketoprofen, and diclofenac have been detected in the groundwater and SGD of the Baltic Sea. General human and animal biotransformation can weaken the life cycle of pharmaceuticals, but microbes also degrade pharmaceuticals further in the wastewater treatment process. The impact of emerging pollutants, including endocrine disruption, immunotoxicity, neurological disorders, and cancers in various organisms, is relatively muted in aquatic systems compared to their impact on humans and animals in terrestrial environments. This is largely due to relatively low concentrations (≤lower microgram/liter) because of dilution, aerobic/anaerobic biotransformation, and adsorption by sediment or biofilm. Nonetheless, the significance of emerging pollutants in aquatic systems should not be minimized, as their detrimental downstream effects, such as antibiotic resistance, traverse across geopolitical boundaries and constitute a shared global concern. Wastewater is the major source of pharmaceuticals and their metabolites in highly urbanized environments. Without proper wastewater treatment, PPCP contamination increases the health risk for humans and other animals through consumption of and contact with contaminated water. Poor treatment of wastewater leads to the release of PPCPs into receiving streams and ultimately into the coastal waters. Many clean-up procedures are not designed to specifically remove PPCPs from the wastewater completely, and even the most advanced sewage treatment processes are proven ineffective in completely removing pharmaceuticals from the wastewater. In the Philippines, wastewater treatment is still developing. In urban regions, only 10% of septage is safely treated and disposed of, 4% of the total wastewater is treated, and about 3% of the population openly defecates in nearby water bodies due to the lack of proper facilities. Previous studies on PPCP contamination were mostly focused on Metro Manila and adjacent urbanized provinces, but studies for highly populated coastal areas are severely lacking. Coastal sites vary in land-use, geology, population density, coastal tourism, and other anthropogenic factors, which determines the nature and intensity of environmental pollution. This study aimed to identify and quantify PPCP contaminants in key aquatic environments in the Philippines, examine their distribution in relation to population density and land-use, and determine how seasonal and physicochemical factors influence the variation in PPCP concentrations within the same sites. Samples from various aquatic matrices, such as hospital wastewater, surface and river, and coastal waters, were collected for common PPCPs and antibiotics analyses. The study focused on two watershed continuums (Davao Gulf, Davao City; Macajalar Bay, Cagayan de Oro City), two tourist areas (Boracay Island, Aklan; Mabini, Batangas), and one pristine atoll (Tubbataha Reefs, Palawan), all with varied prevailing human population pressures. The study found that acetaminophen was detected at concentrations of up to 289.17 ppb in freshwater samples, and at concentrations of up to 253.39 ppb in seawater samples. Caffeine was ubiquitous to all the sites, reaching 1848.57 ppb. Sulfamethazine, a commonly used veterinary antibiotic, was detected at 764.91 ppb in a river site in Cagayan de Oro. Untreated hospital wastewater contained metformin, iopamidol, sulfamethoxazole, acetylsulfamethoxazole, ciprofloxacin, and azithromycin, but these pharmaceuticals were not detected in other river and coastal waters. Samples collected during the dry season exhibited higher concentrations than those from the wet season, which appears to be related to an increase in transient populations from tourism activities as well as dilution. The presence of pharmaceutical residues and antibiotics in these areas and the potential impact on the environment indicate the need for stricter wastewater management measures, particularly in communities located near water bodies. As the results of this study show, such measures might be most beneficial and effective if imposed during the dry season and in areas open to tourism.