Tran et al. (2019) reported 31 ECs in untreated wastewater, treated wastewater,
urban storm runoff, agricultural runoff, and in freshwater which frequently influence
the quality of urban surface water. For identifying and characterizing the origin of
diffuse source in urban wastewater, selected ECs are developed as a marker. Twentyone target ECs were detected 100% in the collected raw wastewater, samples with
median concentrations ranging from 49.6 to 77,721 ng/L, while only 13 compounds
were found with detection frequency > 50% in freshwater bodies. The median
concentration of the majority of detected ECs was below 100 ng/L in freshwater
samples. Thus, analysis of ECs such as acesulfame, acetaminophen, cyclamate, and
saccharine may serve as a suitable marker of diffuse source in surface water.
6.4 Impacts of Wastewater on Natural Ecosystem
Water is necessary for survival of living organisms as it is susceptible in quality and
limited in quantity or availability (Khan et al. 2018). Due to the increasing demand
of freshwater or potable water for different purposes in different sectors like agriculture, industries, domestic, etc., threaten its sustainable use. Wastewater irrigation
appears to be a good alternative source to enhance the availability of potable water
for various purposes. However, wastewater also contains several chemical toxicants
and harmful microbes. Long-term uses of untreated or treated wastewater in agriculture field considerably enhance the potential toxic metal content in soil and
growing plants. These toxicants may further threaten food chain because of several
human health hazardous effects (Dogan et al. 2014). Suitable strategies for proper
foretelling of heavy metal uptake by food crops will help in appropriate risk
assessment of wastewater irrigated soils. Soil, groundwater, or surface water and
growing plants are impacted by long-term wastewater irrigation which is summarized as below.
6.4.1 Soil Characteristics
6.4.1.1 pH and Electrical Conductivity
Wastewater irrigation affects the physicochemical properties of soil such as pH,
electrical conductivity, soil temperature, organic matter, cation exchange capacity,
bulk density, soil porosity, soil hydraulic conductivity, and infiltration rate. Several
studies have shown that soil pH lowered down by wastewater irrigation due to
oxidation of participating cations (Khalid et al. 2018). Solubility of heavy metals
increases at lower pH and causes an increase in heavy metal bioavailability in the soil
which can be easily taken up by the growing plants (Zhao et al. 2015). Net negative
charge, i.e., cation exchange capacity increases at higher pH and positive charge, i.e.,
anion exchange capacity increases at lower pH. Adsorption of metals is also affected
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P. K. Singh and R. K. Sharma
urban storm runoff, agricultural runoff, and in freshwater which frequently influence
the quality of urban surface water. For identifying and characterizing the origin of
diffuse source in urban wastewater, selected ECs are developed as a marker. Twentyone target ECs were detected 100% in the collected raw wastewater, samples with
median concentrations ranging from 49.6 to 77,721 ng/L, while only 13 compounds
were found with detection frequency > 50% in freshwater bodies. The median
concentration of the majority of detected ECs was below 100 ng/L in freshwater
samples. Thus, analysis of ECs such as acesulfame, acetaminophen, cyclamate, and
saccharine may serve as a suitable marker of diffuse source in surface water.
6.4 Impacts of Wastewater on Natural Ecosystem
Water is necessary for survival of living organisms as it is susceptible in quality and
limited in quantity or availability (Khan et al. 2018). Due to the increasing demand
of freshwater or potable water for different purposes in different sectors like agriculture, industries, domestic, etc., threaten its sustainable use. Wastewater irrigation
appears to be a good alternative source to enhance the availability of potable water
for various purposes. However, wastewater also contains several chemical toxicants
and harmful microbes. Long-term uses of untreated or treated wastewater in agriculture field considerably enhance the potential toxic metal content in soil and
growing plants. These toxicants may further threaten food chain because of several
human health hazardous effects (Dogan et al. 2014). Suitable strategies for proper
foretelling of heavy metal uptake by food crops will help in appropriate risk
assessment of wastewater irrigated soils. Soil, groundwater, or surface water and
growing plants are impacted by long-term wastewater irrigation which is summarized as below.
6.4.1 Soil Characteristics
6.4.1.1 pH and Electrical Conductivity
Wastewater irrigation affects the physicochemical properties of soil such as pH,
electrical conductivity, soil temperature, organic matter, cation exchange capacity,
bulk density, soil porosity, soil hydraulic conductivity, and infiltration rate. Several
studies have shown that soil pH lowered down by wastewater irrigation due to
oxidation of participating cations (Khalid et al. 2018). Solubility of heavy metals
increases at lower pH and causes an increase in heavy metal bioavailability in the soil
which can be easily taken up by the growing plants (Zhao et al. 2015). Net negative
charge, i.e., cation exchange capacity increases at higher pH and positive charge, i.e.,
anion exchange capacity increases at lower pH. Adsorption of metals is also affected
128
P. K. Singh and R. K. Sharma