evenness [48]. Endocrine disruptors and a myriad of pharmaceutical products,
antimicrobials, personal care products, lipid regulator agents, anti-inflammatory
drugs, beta-blockers, cancer therapeutics, contraceptives, and other hormones are
contaminants of emerging concern [22, 49]. Some of them are not degraded at all, or
degraded at low level by the WW microbiota.
A very interesting recent discovery made by Susan D. Richardson et al., from the
University of South Carolina shows that compounds used for medical imaging
(X-ray contrast media) can react with chlorine or chloramines in drinking water
treatment to form the most toxic iodinated disinfection by-products (DBPs) identified to date [50]. Even though X-ray contrast media are nontoxic to humans in their
parent form and are excreted within about 24 h, these iodinated disinfection
by-products are very resistant to degradation in the WWTP, such that high levels
are released to rivers and streams (up to 100 ppb) and can enter drinking water
sources to form these highly toxic DBPs.
In the United States, concerns grow over tainted sewage sludge spread on
croplands because of the perfluoroalkyl and polyfluoroalkyl substances (PFAS) in
biosolids. PFASs are extensively used in the manufacture of surfactants, lubricants,
polishes, textile coatings, and fire-retarding foams. On September 12, 2019, John
Flesher and Michael Casey of the Associated Press reported that in Maine, a dairy
farm was forced to shut down because of high levels of PFAS in the milk, after
sludge land spreading. The concern is that certain PFAS chemicals, which studies
have associated with an increased risk of cancer and damage to organs such as the
liver and thyroid, could be absorbed by crops grown in soils treated with polluted
sludge and wind up in foods. The Food and Drug Administration agency reported
finding substantial levels of the chemicals in random samples of grocery store meats,
dairy products, seafood, and even off-the-shelf chocolate cake, although the study
did not mention any connection to sewage waste (https://apnews.com/
32c65a5b3c27468ea2cdd2ce97848825). The significant loading of PFAS to US
soils further increases concern about groundwater and surface water
contamination [51].
Hence, collaborative projects are needed between environmental chemists, microbiologists, and engineers to harness the potential of new screening techniques for
assessing the environmental and ecological impact of micropollutants, their metabolic end products, and their derivatives on overall ecological health.
4 The Sludge Microbiome Composition: An Untapped
Diversity – Potential Consequences of WW Irrigation
and Sludge Spreading on Agricultural Soil
Sludge from WWTP concentrates 85 to 90% of solid and contains a large amount of
prokaryotic microorganisms, which account for 95% of the microbiota. These
microorganisms include functional groups that ensure carbon removal by oxidation
Environmental, Economic, and Ethical Assessment of the Treated Wastewater and. . .
59
antimicrobials, personal care products, lipid regulator agents, anti-inflammatory
drugs, beta-blockers, cancer therapeutics, contraceptives, and other hormones are
contaminants of emerging concern [22, 49]. Some of them are not degraded at all, or
degraded at low level by the WW microbiota.
A very interesting recent discovery made by Susan D. Richardson et al., from the
University of South Carolina shows that compounds used for medical imaging
(X-ray contrast media) can react with chlorine or chloramines in drinking water
treatment to form the most toxic iodinated disinfection by-products (DBPs) identified to date [50]. Even though X-ray contrast media are nontoxic to humans in their
parent form and are excreted within about 24 h, these iodinated disinfection
by-products are very resistant to degradation in the WWTP, such that high levels
are released to rivers and streams (up to 100 ppb) and can enter drinking water
sources to form these highly toxic DBPs.
In the United States, concerns grow over tainted sewage sludge spread on
croplands because of the perfluoroalkyl and polyfluoroalkyl substances (PFAS) in
biosolids. PFASs are extensively used in the manufacture of surfactants, lubricants,
polishes, textile coatings, and fire-retarding foams. On September 12, 2019, John
Flesher and Michael Casey of the Associated Press reported that in Maine, a dairy
farm was forced to shut down because of high levels of PFAS in the milk, after
sludge land spreading. The concern is that certain PFAS chemicals, which studies
have associated with an increased risk of cancer and damage to organs such as the
liver and thyroid, could be absorbed by crops grown in soils treated with polluted
sludge and wind up in foods. The Food and Drug Administration agency reported
finding substantial levels of the chemicals in random samples of grocery store meats,
dairy products, seafood, and even off-the-shelf chocolate cake, although the study
did not mention any connection to sewage waste (https://apnews.com/
32c65a5b3c27468ea2cdd2ce97848825). The significant loading of PFAS to US
soils further increases concern about groundwater and surface water
contamination [51].
Hence, collaborative projects are needed between environmental chemists, microbiologists, and engineers to harness the potential of new screening techniques for
assessing the environmental and ecological impact of micropollutants, their metabolic end products, and their derivatives on overall ecological health.
4 The Sludge Microbiome Composition: An Untapped
Diversity – Potential Consequences of WW Irrigation
and Sludge Spreading on Agricultural Soil
Sludge from WWTP concentrates 85 to 90% of solid and contains a large amount of
prokaryotic microorganisms, which account for 95% of the microbiota. These
microorganisms include functional groups that ensure carbon removal by oxidation
Environmental, Economic, and Ethical Assessment of the Treated Wastewater and. . .
59