Just a bit more about polution.Manganese, lead and strontium bioaccumulation in the tissues
of the yellowfish, Barbus marequensis from the lower Olifants
River, Eastern Transvaal
Tharina Seymore*, Hein H du Preez and JHJ van Vuren
Department of Zoology and RATE, Rand Afrikaans University, PO Box 524, Auckland Park 2006, South Africa Abstract
The bioaccumulation of manganese, lead and .strontium in the freshwater fish (Barbus marequensis) from the lower Olifants River
. was investigated. The highest concentrations of these metals were detected in the vertebrae and gills. The localities
in the Kruger National Park did not differ significantly fron each other and therefore no clear indication as to where the highest bioaccumulatuion had occurred, could be established. However, the highest manganese and strontium levels occurred in fish Irom the Selali River. Tor the future monitoring of manganese, lead and strontium levels in bony fish, it is suggested that bony tissues (e.g. vertebrae, opercular bone or scales), gills, liver and muscle [issue are used.Introduction
Manganese, lead and strontium appear to be metabolised via calcium metabolic pathways (Hammond and Beliles, 1980) and,therefore, accumulate mainly in the skeletal tissues of fish (Paul and Pillai, 1983; Patterson and Settle, 1977;Bagenaletal., 1973).
Manganese is an essential trace element and shows relatively low
toxicity to aquatic biota. Lead is a non-essential metal and is
known to be toxic to aquatic organisms, especially fish (Klein,
1962). The requirement of strontium by fish has not been
established, but appears to be a non-essential metal, for although it
is a bone-seeking element, strontium is not essential for bone
formation (Sauer and Watabe, 1989).
In the natural freshwaters, manganese is rarely found at
concentrations above 1 mg/1 (Hellawell, 1986), while concentrations
of soluble lead are generally less <3ug/l (Forstner and Wittmann,
1979). Strontium values in South African surface waters typically
range from 50 to several hundred ug/l (Kempster, 1994). The forms
in which manganese and lead occur in freshwater are mainly
particulate or complexed forms (Seenayya and Prahalad, 1987;
Moore and Ramamoorthy, 1984), decreasing the bioavailability of
these metals to the fish. As the pH of the water decreases, however,
the ionic state of the metals becomes more prevalent and toxicity
increases (Wang, 1987). Strontium, on the other hand, is found in
water in solution rather than in particulate form (Carraca et
al.,1990) and might, therefore, be more bioavailable to fish for
uptake. Nevertheless, in calcium-rich waters calcium will compete
with strontium in the uptake process, resulting in lower strontium
accumulation by the fish (Phillips and Russo, 1978). Factors such
as the water pH, water hardness, organic materials and other metals
will, therefore, influence the toxicity of these metals, but there also
seems to be a relation between the concentrations of these metals
in the water and the accumulation thereof by freshwater fish
The manganese, lead and strontium concentrations in the water
can increase to quite an extent due to the influence of industrial
wastes and mining effluents on the river. The combustion of oil
and gasoline accounts for more than 50% of anthropogenic lead
emissions and therefore atmospheric fall-out is usually the most
important source of lead in freshwaters (Moore and Ramamoorthy,
1984). Fish can be affected sublethally when they are chronically
exposed to lead concentrations ranging between 5 and 5 000 ug/l
inorganic lead (Haux et al., 1986). Two distinctive characteristics
of chronic lead poisoning in fish are black tails, also an early
symptom of spinal deformities (Hodson et al., 1979), and a strong
inhibition of the aminolevulinic acid dehydratase (ALA-D) activity
in erythrocytes (Haux et al., 1986). The 96-h LC50 value of total
lead for freshwater fish varies from 0.5 to 482 mg/lPb, depending
on the water hardness and life stage of the fish (Moore and
Ramamoorthy, 1984; Pickering and Henderson, 1966).
Manganese and strontium can also affect fish adversely at
elevated levels, but limited research has been done in this field.
Sublethal effects can occur at a manganese concentration of 0.278
g/l (Seymore, 1994), while the 96-h LC50 value can vary from
1.723 to 3.230 g/l Mn (Nath and Kumar, 1987). For strontium the
96-h LC50 value for fish has been determined to be greater than
92.8 mg/l Sr (Dwyer et al., 1992). The general order in which the
relevant three metals can affect fish, is therefore: Pb > Mn > Sr.
Associated factors, such as environmental conditions, should,
however, be taken into consideration when assessing the toxicity
of these metals to fish.
The objective of this study was to determine the extent of
bioaccumulation (with respect to site, seasons, years, age, tissues)
of manganese, lead and strontium in the yellow fish, Barbus
marequensis from the lower Olifants River, E. Transvaal.
data were also used to establish which of the tissues contained the
highest and lowest concentrations of these metals, respectively.The Olifants River was selected as study area because it is one of
the most important rivers that flows through the Kruger National
Park. Furthermore, anthropogenic activities in the catchment of
this river may effect the quality of the water flowing through the
Kruger National Park.
* To whom all correspondence should be addressed.
Present address: Institute for Water Quality Studies, Private Bag X313,
Pretoria 0001, South Africa
(012) 808-0374; [F](012) 808-0338; e-mail email@example.com
Received 14 July 1994; accepted in revised form 8 November 1994.