396
chemicals and pharmaceuticals described as ECs such as 17β-estradiol (E2),
17α-ethinylestradiol (EE2), and diclofenac also cause water contamination. To date,
millions of different industries alone have been responsible for water contamination
and toxicity globally, with concentrations up to a maximum of 6.5 mg/L for the
antibiotic ciprofloxacin [1, 2]. In this report, single-compound acute toxicity testing
(including crustaceans, algae, and bacteria) has been conducted under controlled
laboratory conditions that has found median effective concentrations (EC 50 s—concentration at which the toxicological response to an organism is halfway between a
normal and maximum response for a preset time period) for a number of these ECs
to be <1 mg/L [3, 4]. Such effect concentrations classify the chemical as potentially
very toxic to aquatic organisms [5, 6]. The presence of these chemicals in the environment is more concerning considering that they do not appear individually, but as
a complex mixture, which could lead to unwanted synergistic effects. The ubiquity
of a high number of potentially toxic ECs in the environment underpins the need to
better understand their occurrence, fate, and ecological impact. This report describes
current knowledge on the occurrence of ECs in wastewaters and surface waters
using the standard data set as a model to represent global water contamination.
From the data set and wider literature, areas of concern considered to be understudied are discussed considering spatial and temporal variability of ECs in wastewater
and river water, partitioning of ECs to solid matter during wastewater treatment, fate
of ECs in environmental waters, and toxicological impact of ECs within the environment. Finally, recommendation for future water environmental monitoring
approaches is proposed for contaminant- and toxic-free water world.
Materials and Methods
The presence of ECs in the water environment is mainly attributed to the discharge of
treated wastewater from wastewater treatment plants (WwTPs) which is contaminated by chemicals where aquatic environment gets polluted which has the impact on
dissolved oxygen in the body of water and causes rapid growth of deadly microorganisms. Conventional secondary processes (activated sludge and trickling filters) represent the most extensively used and studied processes and are therefore focused on in
this report. However, this report is not designed to remove ECs which are discharged
to receiving surface waters including rivers, lakes, and coastal waters but describes
the impact of chemicals such as chlorine, acetaminophen, amitriptyline, EMDP,
dosulepin, fluoxetine, norfluoxetine, triclosan, ofloxacin and ciprofloxacin, NSAIDs,
β-blockers, antidepressants, and the antiepileptic carbamazepine on influent wastewaters [7, 8]. Some researchers suggested that removal of chemicals like chlorine and
acetaminophen varies broadly from low (<50%) to high (>80%) due to their different
physicochemical properties such as susceptibility to microbiological attack in the
water environment by receiving surface waters in the ng to mg/L range which leads
to surface water getting severely contaminated [9, 10]. Thus, in this research a large
variation in influent wastewater concentrations (equivalent to more than an order of
19 Water
chemicals and pharmaceuticals described as ECs such as 17β-estradiol (E2),
17α-ethinylestradiol (EE2), and diclofenac also cause water contamination. To date,
millions of different industries alone have been responsible for water contamination
and toxicity globally, with concentrations up to a maximum of 6.5 mg/L for the
antibiotic ciprofloxacin [1, 2]. In this report, single-compound acute toxicity testing
(including crustaceans, algae, and bacteria) has been conducted under controlled
laboratory conditions that has found median effective concentrations (EC 50 s—concentration at which the toxicological response to an organism is halfway between a
normal and maximum response for a preset time period) for a number of these ECs
to be <1 mg/L [3, 4]. Such effect concentrations classify the chemical as potentially
very toxic to aquatic organisms [5, 6]. The presence of these chemicals in the environment is more concerning considering that they do not appear individually, but as
a complex mixture, which could lead to unwanted synergistic effects. The ubiquity
of a high number of potentially toxic ECs in the environment underpins the need to
better understand their occurrence, fate, and ecological impact. This report describes
current knowledge on the occurrence of ECs in wastewaters and surface waters
using the standard data set as a model to represent global water contamination.
From the data set and wider literature, areas of concern considered to be understudied are discussed considering spatial and temporal variability of ECs in wastewater
and river water, partitioning of ECs to solid matter during wastewater treatment, fate
of ECs in environmental waters, and toxicological impact of ECs within the environment. Finally, recommendation for future water environmental monitoring
approaches is proposed for contaminant- and toxic-free water world.
Materials and Methods
The presence of ECs in the water environment is mainly attributed to the discharge of
treated wastewater from wastewater treatment plants (WwTPs) which is contaminated by chemicals where aquatic environment gets polluted which has the impact on
dissolved oxygen in the body of water and causes rapid growth of deadly microorganisms. Conventional secondary processes (activated sludge and trickling filters) represent the most extensively used and studied processes and are therefore focused on in
this report. However, this report is not designed to remove ECs which are discharged
to receiving surface waters including rivers, lakes, and coastal waters but describes
the impact of chemicals such as chlorine, acetaminophen, amitriptyline, EMDP,
dosulepin, fluoxetine, norfluoxetine, triclosan, ofloxacin and ciprofloxacin, NSAIDs,
β-blockers, antidepressants, and the antiepileptic carbamazepine on influent wastewaters [7, 8]. Some researchers suggested that removal of chemicals like chlorine and
acetaminophen varies broadly from low (<50%) to high (>80%) due to their different
physicochemical properties such as susceptibility to microbiological attack in the
water environment by receiving surface waters in the ng to mg/L range which leads
to surface water getting severely contaminated [9, 10]. Thus, in this research a large
variation in influent wastewater concentrations (equivalent to more than an order of
19 Water