Occurrence and toxicological assessment of selected active pharmaceutical ingredients in effluents of pharmaceutical manufacturing plants and wastewater treatment plants in Kampala, Uganda

Abstract

There is an increasing eco-toxicological risk associated with pharmaceuticals globally. The prevalence of six active pharmaceutical ingredients (APIs) was studied in effluents of three pharmaceutical manufacturing plants (PMPs) and two wastewater treatment plants (WWTPs) in Kampala, Uganda to ascertain the removal potentials for APIs. The APIs include atenolol, losartan, carbamazepine, sulfamethoxazole, clarithromycin, and diclofenac. The APIs were extracted using solid-phase extraction cartridges and concentrations were analyzed using a liquid chromatography-mass spectrometer system. The concentration ranges of the APIs were <LOD, <LOD - 4.75, <LOD – 1.37, <LOD – 1.17, and 0.28–19.55 mgL−1 for losartan, diclofenac, sulfamethoxazole, carbamazepine, and clarithromycin respectively in effluents of WWTPs whereas in treated wastewater from PMPs concentrations were 0.00, 0.00–0.23, 5.30–7.4, 0.00–0.14, and 0.12–4.53 mgL−1 for losartan, diclofenac, sulfamethoxazole, carbamazepine, and clarithromycin respectively. The API removal efficiency of PMPs was higher than WWTPs with some APIs removed to concentrations of <LOD. The range of hazard quotients (HQs) for APIs was 0.018–0.9775000 with most of the APIs posing remarkably high environmental risks at HQs way greater than 1. Only sulfamethoxazole from the effluents of Lubigi WWTP, Bugolobi WWTP, and PMP C posed low risks with hazard quotients of <1 at 0.018, 0.305, and 0.018 respectively. The high hazard quotients for most APIs imply that immediate recipients are at very high toxicological risks, yet most studies have focused on the final destinations of APIs in environments where toxicological risks are often minimal due to dilution effects.

Emerging Pollutants in Uganda: A Systematic Review

“…Similarly, the presence various chemicals, including pesticides (27,46), perfluorinated alkylated substances (PFAS) (47), personal care products (39), and persistent organic pollutants (POPs) (36), has been documented in surface waters, with concentrations exceeding regulatory limits in some cases, indicating potential risks to agricultural productivity and human health (19,38,48). Their contamination poses a significant public health concern as it can be detrimental to freshwater resources, similar to the concerns raised in previous studies (38).…”

“…To date, several studies have been conducted in Uganda to investigate the presence and concentrations of emerging pollutants in different environmental systems in Uganda for example in water (27,28), sediments (27,29), surface waters (30)(31)(32), food crops (33,34), edible insects (35), breastmilk (36) and in fish (30). These studies have identified a range of compounds, including pharmaceutical residues (e.g., antibiotics, analgesics) (26,37,38), personal care products (e.g., fragrances, UV filters) (39), pesticides (e.g., herbicides, insecticides) (27,35,40,41), industrial chemicals (e.g., flame retardants, plasticizers) (36,39,42), microplastics and heavy metals (43)(44)(45). The concentrations of emerging pollutants reported in the literature vary depending on the sampling location, environmental matrix, and analytical techniques used.…”

“…The concentrations of emerging pollutants reported in the literature vary depending on the sampling location, environmental matrix, and analytical techniques used. For instance, studies have detected antibiotics in surface waters at concentrations ranging from 1 ng/L to 5600 ng/L, highlighting the potential impact of pharmaceutical pollution on aquatic ecosystems (26,38). Large volumes of pharmaceuticals are produced and consumed annually, but not all medications are properly used or disposed of.…”

“…However, there is a sparsity of information on the disposal methods and protocols used by healthcare professionals, including community pharmacists, in Uganda (38).The lack of sufficient information and a strong national guideline for medication disposal and poor compliance with existing guidelines increases the risk of environmental contamination and the ingestion of toxic pharmaceutical waste by humans and animals. Similarly, the presence various chemicals, including pesticides (27,46), perfluorinated alkylated substances (PFAS) (47), personal care products (39), and persistent organic pollutants (POPs) (36), has been documented in surface waters, with concentrations exceeding regulatory limits in some cases, indicating potential risks to agricultural productivity and human health (19,38,48). Their contamination poses a significant public health concern as it can be detrimental to freshwater resources, similar to the concerns raised in previous studies (38).…”

“…Wastewater treatment plant (WWTP) effluents have been identified as important sources of contamination in Uganda (37,38,48,49). These WWTPs serve as receptacles for anthropogenic pollution, and due to the lack of specific treatment methods for organic pollutants, some compounds remain poorly degraded (48,50).…”