Gogoi et al. 2018; Wilkinson et al. 2017). The main CECs identified to date in
municipal and industrial wastewater include organic compounds such as personal
care products (fragrance, detergents, lotions, deodorants, cleaning products, sunscreens and ultraviolet filters, etc.), pharmaceuticals (analgesics, anesthetics, antimicrobials, anti-inflammatory drugs, sedatives, etc.), illicit drugs, pesticides,
nanomaterials, flame retardants, cyanotoxins, and hormones. Some of these compounds are known or suspected to have adverse effects on wildlife endocrine
systems and human health (Shaver 2011; Wilkinson et al. 2017). This list is
non-exhaustive as the variety and the number of the compounds released to the
environment is in constant evolution and expected to significantly grow in the
future because of advancements in chemical, medical, and pharmaceutical industries and improvements of analytical methods to detect them and their degradation
products/metabolites in complex matrix (Rodriguez-Narvaez et al. 2017).
Similarly to municipal wastewater, in mine water, CECs can be classified into at
least four categories (Neculita et al. 2018): (1) new contaminants (e.g., rare earth
elements—REE, Se, Mn); (2) contaminants that are difficult to treat (e.g., sulfates,
salinity); (3) known contaminants, but with low target/regulatory criteria in sensitive
environments, particularly in the northern climate (e.g., As, Cu), and (4) nitrogenous
contaminants (NH 3 , NO 2
À , NO 3
À ), for which either regulatory criteria are clearly
defined or they are controlled via the monitoring of aquatic toxicity. Potential
sources of toxicity in mine effluents include free acidity, depressed or high pH,
dissolved metals, nitrogen compounds, thiosalts, xanthates, etc. (ESG International
Inc. and Lakefield Research 2002). In gold mine effluents, toxicants also include
cyanides and derivatives, As, and total suspended solids (TSS).
Finally, soil and sediment contamination by CECs results from various inputs.
These may be divided into two different areas: (1) dumping materials, bankrupt and
abandoned manufacturing plants, insufficient methods for waste storage, treatment
of soils/sediments and urban and industrial disposal facilities, and (2) use of
chemicals for nutrient supplementation, weed and pest control, and other agricultural
practices resulting in pollution of surface water and excessive nitrogen and phosphate loadings (Yong et al. 2014).
The toxicity of CECs is poorly known (Sauvé and Desrosiers 2014). For example,
toxicity associated with ion imbalance can occur if ion concentrations exceed or do
not meet the physiological tolerance of the organisms present in the receiving
ecosystem (Goodfellow et al. 2000). The internal ionic concentration of the cells
must be maintained, so that the cellular functions are also maintained (Cormier et al.
2013), these being often based on temporary changes of the ionic equilibria implying
osmotic and cellular processes. If the external ion concentration increases, a disruption of ionic equilibrium occurs and other effects can also be entailed, including an
osmotic shock or oxidative stress that can lead to the death of organisms (Cormier
et al. 2013; Goodfellow et al. 2000). Among other factors, salinity/total dissolved
solids (TDS) is a major contributor to the toxicity (Banks et al. 1997; Goodfellow
et al. 2000; Kennedy et al. 2005; van Dam et al. 2014). The sensitivity to salinity is
organism-dependent and the effects can be seen on algal growth, growth and
reproduction of pelagic (e.g., Daphnia) and benthic (e.g., amphipod) invertebrates,
29 Future Prospects for Treating Contaminants of Emerging Concern in. . .
591
municipal and industrial wastewater include organic compounds such as personal
care products (fragrance, detergents, lotions, deodorants, cleaning products, sunscreens and ultraviolet filters, etc.), pharmaceuticals (analgesics, anesthetics, antimicrobials, anti-inflammatory drugs, sedatives, etc.), illicit drugs, pesticides,
nanomaterials, flame retardants, cyanotoxins, and hormones. Some of these compounds are known or suspected to have adverse effects on wildlife endocrine
systems and human health (Shaver 2011; Wilkinson et al. 2017). This list is
non-exhaustive as the variety and the number of the compounds released to the
environment is in constant evolution and expected to significantly grow in the
future because of advancements in chemical, medical, and pharmaceutical industries and improvements of analytical methods to detect them and their degradation
products/metabolites in complex matrix (Rodriguez-Narvaez et al. 2017).
Similarly to municipal wastewater, in mine water, CECs can be classified into at
least four categories (Neculita et al. 2018): (1) new contaminants (e.g., rare earth
elements—REE, Se, Mn); (2) contaminants that are difficult to treat (e.g., sulfates,
salinity); (3) known contaminants, but with low target/regulatory criteria in sensitive
environments, particularly in the northern climate (e.g., As, Cu), and (4) nitrogenous
contaminants (NH 3 , NO 2
À , NO 3
À ), for which either regulatory criteria are clearly
defined or they are controlled via the monitoring of aquatic toxicity. Potential
sources of toxicity in mine effluents include free acidity, depressed or high pH,
dissolved metals, nitrogen compounds, thiosalts, xanthates, etc. (ESG International
Inc. and Lakefield Research 2002). In gold mine effluents, toxicants also include
cyanides and derivatives, As, and total suspended solids (TSS).
Finally, soil and sediment contamination by CECs results from various inputs.
These may be divided into two different areas: (1) dumping materials, bankrupt and
abandoned manufacturing plants, insufficient methods for waste storage, treatment
of soils/sediments and urban and industrial disposal facilities, and (2) use of
chemicals for nutrient supplementation, weed and pest control, and other agricultural
practices resulting in pollution of surface water and excessive nitrogen and phosphate loadings (Yong et al. 2014).
The toxicity of CECs is poorly known (Sauvé and Desrosiers 2014). For example,
toxicity associated with ion imbalance can occur if ion concentrations exceed or do
not meet the physiological tolerance of the organisms present in the receiving
ecosystem (Goodfellow et al. 2000). The internal ionic concentration of the cells
must be maintained, so that the cellular functions are also maintained (Cormier et al.
2013), these being often based on temporary changes of the ionic equilibria implying
osmotic and cellular processes. If the external ion concentration increases, a disruption of ionic equilibrium occurs and other effects can also be entailed, including an
osmotic shock or oxidative stress that can lead to the death of organisms (Cormier
et al. 2013; Goodfellow et al. 2000). Among other factors, salinity/total dissolved
solids (TDS) is a major contributor to the toxicity (Banks et al. 1997; Goodfellow
et al. 2000; Kennedy et al. 2005; van Dam et al. 2014). The sensitivity to salinity is
organism-dependent and the effects can be seen on algal growth, growth and
reproduction of pelagic (e.g., Daphnia) and benthic (e.g., amphipod) invertebrates,
29 Future Prospects for Treating Contaminants of Emerging Concern in. . .
591