The Environmental Impact of Danube’s Pollution with Heavy Metals

Main sources of water pollution

Water is an medium factor, compulsory and crucial for everyday life, being the most outspread

element on Earth. In nowadays situation, Terra finds itself in a critical period of its life from the pollution point of view and from the struggle for environmental protection point of view. So, a major attention on

aquatic resources protection and on aquatic medium preservation is imposed.

The main sources of water pollution are exposed and classified according to two main criteria

exposed below in figure 1 .

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Presentation of the Danube’s ecosystem and its state

The Danube river ecosystem is crucially important for mankind because of the following elements:

water, fishing stock and the influence on the neighbouring ecosystems.

The Danube biotope and biocoenosis characteristics are exposed bellow.

a)Danube biotope characteristics:

�consolidated water course

�medium deepness 10 meters

�very puddle water

�a lot of sand and mud on the river bottom

�hydrological level depending on depth of rainfall

b)Danube biocoenosis characteristics:

�plants – rich phytoplankton

�invertebrates animals: developed zooplankton, snails, shells, crabs

�vertebrates animals: fish (carp, tench, bream, rudd, bass, catfish, luce) water snakes, birds

(Danube hawk)

Danube’s main sources of pollution

The Danube pollution can affect not only species of plants and fish, but also the potable water

used by the population in its hydro-graphic basin.

Waste waters evacuated in the most of the Romanian big cities across the river pollute massively

the Danube because there are not cleaning stations in those areas.

One of the most important pollutant cities is the capital because the waste water reaches

Dâmboviţa River that discharges in Argeş River and, after 20 km, in the Danube (Driga B.-V., 2006).

A report of Danube Delta Biosphere Administration (DDBA) shows that the traffic extension on

Danube River is leading to water pollution with petroleum products. This pollution takes place because of

unavailability of ships endowment with efficient petroleum remainder separators or, if these do exist, they

are not properly used.

Another problem is that Danube ports are not endowed with specific equipment for residuum

processing and recycling.

Negative effects of water pollution

The main phenomenon caused by heavy metal on environment, living organisms and human

health is both their tendency to accumulate in diverse type of tissues (vegetal, animal or human), and their

toxicity- even in small concentrations.

Over 90% of Cadmium (Cd), Plumb (Pb), Manganese (Mn), Nickel (Ni) and Zinc (Zn) found in

soft water and sediments is coming from human activities that, associated with suspended particles,

accumulates in sediments.

Land sources generating heavy metals are mainly the following: waste waters cleaning equipment,

industries, mining and agriculture.

Metals are transported either dissolved in water or as a whole part of sediments. Once arrived in

aquatic medium, main consequence is that they can be: dissolved in the water gauge, stored in sediments,

volatilised in the atmosphere, absorbed by organisms.

Important effects of water pollution with heavy metals: human and animal health affection; water

source damaging; appropriate alimentation assurance; environmental health affection.

The evaluation of heavy metals content in the Danube’s water (blue bars represent values from Rotundu lake, those bricky from Somova; blue and red lines show the trend of the respective diagram)

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The evaluation of heavy metals content in the Danube’s sediments (blue bars represent values from Rotundu lake, those bricky from Somova; blue and red lines show the trend of the respective diagram)

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The concentrations of all the six heavy metals analyzed in the Danube’s sediments (figure 3 ) are increasing gradually in the following order: Cd <Pb <Ni <Cr <Zn <Mn.

The evaluation of heavy metals content in the Danube’s aquatic vegetation

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Diagrams in figure 4 mark significant variations depending on the vegetation type and metal.

Future evolution of the Danube’s pollution estimation

A descendent tendency of Cd, Pb and Zn concentration can be noticed (figure 2 ), probably due to

waste water regulated discharge in emissary (waste water cleaning equipment). The rest of elements are

following a growing tendency estimated about 8…15 µg/l a year as the graphs’ values are showing.

The concentrations of heavy metals analyzed in sediments are increasing gradually (figure 3 ),

marked as: Cd <Pb <Ni <Cr <Zn <Mn. A descendent tendency of Cd, Pb and Zn concentration is

remarked.The rest of elements are following a growing tendency estimated about 5…60 mg/kg a year.

Following the samples in situ and graphs plotted in figure 4 , an ascendant trend of heavy metals

accumulation in aquatic vegetation is to be remarked, as: Mn<Pb<Cr<Ni<Zn.

Romania pollutes the most Danube’s waters. Germany and Austria, that possess both a shorter part

of Danube, are polluting together as much as Romania.

Typha angustifolia and Phragmites australis are very important due to great ecological production

and their potential in exploitation as construction materials and biological filters for ecosystems.

Potential elements in the Danube’s pollution reduction

�Big factories in industry must adapt a permanent automation system in monitoring the quality of

escaped waters and the impact of waters’ quality escaped in the Danube that is to be verified by

the institutions empowered (National Agency of Environmental Protection, Romanian Waters)

�Cleaning equipment for waste waters in big and medium cities across the country

�Limitation in polluting the water courses by implementing the 91/271/CEEDirective

�Proper management of mud coming from waste water cleaning stations �Using the lab discoveries regarding the bioaccumulation attribute of some superior plants

Actions in the Danube’s pollution reduction

The main actions in heavy metals accumulation reduction are esteemed to be (figure 5 ):

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Strengths of analyse done by the authors in the paper

The main strengths of the analyse presented in the paper are the following:

-The main sources of Danube’s pollution with heavy metals are established

-Based on analyse done in laboratory, some diagrams were plotted regarding the evaluation of heavy

metals content in the Danube’s water, sediments and aquatic vegetation (figures 2 , 3 and 4 )

-Based on the values’ evolution in diagrams, the annual concentration trend is estimated in each case

previously mentioned

-The data processing and presentation in the diagrams plotted are original

-The paper proposes some solutions in decreasing the amount of heavy metals in Danube’s water,

sediments and aquatic vegetation