Aquatic toxicology
in South Africa
Forty years ago, water pollution relied solely
on chemical analysis. Technology has since
evolved to include a battery of protocols to
assess the impact of pollution on aquatic biota.
By Anna Loots
T
he South African Bill of Rights
states that everyone has the
right: (a) to an environment that
is not harmful to their health or well-
being; and (b) to have the environment
protected, for the benefit of present and
future generations, through reasonable
legislative and other measures that:
(i) prevent pollution and ecological
degradation; (ii) promote conservation;
and (iii) secure ecologically sustainable
development and use of natural
resources while promoting justifiable
economic and social development.
However, together with these intrinsic
human rights exists every individual’s
own responsibility for looking after his/
her environment.
The function of aquatic
toxicology
Aquatic toxicology determines the
effects when living organisms within
an aquatic environment are exposed
to toxic chemicals, and in the National
Water Act, 1998 (Act No. 36 of 1998),
Chapter 3 focuses on protection of the
water resource itself.
For the past four decades, standard
practice for the Department of
Wa t e r a n d S a n i t a t i o n ( D W S ) t o
control water pollution relied solely
on chemical analysis, and it was
generally accepted that chemical
monitoring was sufficient to provide
the framework for water quality and
effluent management. This applied
mainly to industries’ discharge and
water samples from dams, rivers,
and streams. Although very valuable,
the chemical testing approach to
determining pollutants had proved to
be insufficient to assess the actual
impact of pollution on aquatic biota.
In the meantime, many other countries
38
(for example Germany, Canada, the
United States of America, and New
Zealand) had researched, developed,
and successfully applied standardised
toxicity test protocols. Limits were
set and had led to routine toxicity
testing for compliance and regulatory
monitoring.
Subsequently, the DWS implemented
its own extensive water quality network
for South Africa, based on routine
sampling of water bodies and analysing
samples for their chemical profile.
The Management of Complex
Industrial Waste Water: Introducing
the Direct Estimation of the Ecological
Effect Potential (DEEEP) approach by
the then Department of Water Affairs
and Forestry in 2003, is a recommended
battery of tests that can measure
toxicity of complex mixtures, even if all
the constituents are not known.
High biochemical/chemical oxygen demand
(COD<200mg/ℓ or BOD<50mg/ℓ)
Acute toxicity
(Battery of tests including bacteria, algae, invertebrates and vertebrates)
Chronic toxicity
Mutagenicity
This battery of tests supports
the Driepootpot approach.
Water Sewage & Effluent March/April 2018
Bioaccumulation