ENVIRONMENT AND ENERGY
Box 1: Emerging pollutants
Box 2: Banning wastewater contaminants:
the example of microbeads
Emerging pollutants are found in varying concentrations in
treated and untreated municipal wastewater, industrial effluents
and agricultural runoff that seeps into rivers, lakes, and coastal
waters. They have also been detected in drinking water, as
conventional wastewater treatment and water purification
processes are not effective in removing them. Microbeads are found in certain consumer products, such as facial cleansers
and toothpaste. After use, these spherical particles made of polyethylene or
polypropylene end up in wastewater. Once microbeads enter the wastewater
system, few wastewater treatment facilities are able to remove them from the
water streams.
Advanced wastewater treatment technologies (membrane
filtration, nanofiltration, ultrafiltration and reverse osmosis) can
partially remove some chemicals and pharmaceutically active
compounds. Risks to aquatic life and public health are not yet well understood, but the
particles themselves may contain toxins or attract other toxins in the water. In
December 2015, the US Government required US manufacturers to end the use
of microbeads in products by 1 July 2017, and the sale of products containing
microbeads by 1 July 2018.
Potential human health risks of emerging pollutants through
exposure via drinking water, as well as via agricultural products,
remain a concern. The effects of individual pollutants on human
and ecosystem health have been only marginally evaluated,
whereas the cumulative effects have not been studied at all.
There is scientific evidence that many chemicals recognised as
emerging pollutants can potentially cause endocrine disruption
in humans and aquatic wildlife (causing birth defects and
developmental disorders, and affecting fertility and reproductive
health), even at very low concentrations, as well as cancerous
tumours and the development of bacterial pathogen resistance,
including multi-drug resistance.
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In June 2016, Canada added microbeads to the list of toxic substances
under the Canadian Environmental Protection Act (CEPA), thus enabling the
government to regulate and ban the use of microbeads (Government of Canada,
2016). In September 2016, the Government of the United Kingdom announced
plans to ban microbeads in cosmetics and personal care products
(DEFRA, 2016).
Microbeads can easily be replaced with natural ingredients like almond and
apricot shells, and several large companies have already announced that they
will end the use of these microplastic products. The joint action between public
and private sectors effectively eliminated economic arguments for delaying a
ban on these substances.
IMPACTS OF RELEASING UNTREATED OR
INADEQUATELY TREATED WASTEWATER
The discharge of untreated or partially treated
wastewater into the environment results in the pollution
of surface water, soil, and groundwater.
Once discharged into water bodies, wastewater is either
diluted and transported downstream or it infiltrates into
aquifers, where it can affect the quality (and therefore
the availability) of freshwater supplies.
The ultimate destination of wastewater discharged into
rivers and lakes is often the ocean.
The consequences of releasing untreated or
inadequately treated wastewater can be classified into
three groups:
• Adverse human health effects associated with
reduced water quality;
• Negative environmental effects due to the
degradation of water bodies and ecosystems; and
• Potential effects on economic activities.
HUMAN HEALTH EFFECTS
Even though household sanitation facilities have
increasingly been improved since 1990, risks to public
health remain due to poor containment, leakages during
emptying and transport, and ineffective sewage treatment.
www.plumbingafrica.co.za
Figure 1: Wastewater components and their effects.
Continued on page 23 >>
January 2018 Volume 23 I Number 11