Hidrológiai Közlöny, 2017 (97. évfolyam)

2017 / 3. szám - TRANSNATIONAL EFFORTS - Sandu, Cristina - Dumitrache, Alina - Radu, Emilia - Dobre, Doru - Tudorache, Mädälina - Mihăilescu, Simona: The importance of good ecological status for the successful revival of Danube sturgeon

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CHEMICAL CHARACTERIZATION

The chemical composition of the aquatic environment is essential for determining water quality. Daily, the aquatic ecosystems receive a cocktail of chemical substances generated by anthropogenic activities, from nutrients to xenobiotics, posing an increasing hazard not only to the environment, but also to human health.

While nutrient and organic pollution are increasingly tackled by the extension of sewage systems and wastewater treatment plants, for hazardous substances, however, there is no control on the total amount, levels and fate of toxic chemicals entering the aquatic ecosysterns. The Water Framework Directive and the EU Watch list require the monitoring of a very limited number of compounds compared to the high diversity of pollutants reaching the water bodies, such as detergents, pesticides, persistent organic pollutants, endocrine disrupters, pharmaceuticals, microplastics, etc.

The high amount of chemical products in use at EU 28 level, posing health hazard to the environment, gives a glimpse at the high contamination risks of EU water bodies with hazardous substances (Table 1), as these substances will eventually find their way into the freshwater or marine systems, i.e. into our drinking, irrigation, bathing and recreational waters.

Hidrológiai Közlöny (Hungarian Journal of Hydrology) 2017. 97. évf. 3. sz.

Table 1. Consumption of chemical substances hazardous for the environment between 2006—2015 (million tons). ____________________________ (Source: EUROSTAT, env chmhaz)______________________________

HAZARD

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

Hazardous and non-hazardous - Total

378.0

388.7

355.0

305.7

355.3

340.3

340.4

338.5

351.8

349.5

Hazardous to health

240.6

244.7

223.8

201.6

226.5

216.8

218.0

214.1

220.2

220.8

Carcinogenic, mutagenic and reprotoxic (CMR) health hazard

39.5

41.7

35.4

35.8

39.4

38.7

34.8

34.4

36.0

34.9

Chronic toxic health hazard

22.4

22.3

22.8

18.4

20.0

18.8

19.8

19.9

19.1

18.2

Very toxic health hazard

46.6

48.8

45.7

37.5

43.1

38.8

41.1

41.6

43.4

44.1

Toxic health hazard

67.0

66.8

61.5

55.0

62.6

60.0

59.7

57.9

57.9

60.1

Harmful health hazard

65.1

65.1

58.4

54.8

61.4

60.5

62.7

60.3

63.8

63.6

Hazardous to the environment

141.0

141.5

131.0

119.2

134.7

129.5

128.9

126.1

126.5

127.0

Severe chronic environmental hazard

42.8

41.6

37.4

35.6

39.6

37.0

37.7

36.8

37.2

37.4

Significant chronic environmental hazard

28.8

29.5

30.1

26.8

30.1

29.8

27.9

26.9

29.7

29.1

Moderate chronic environmental hazard

37.1

38.1

33.8

29.6

34.3

33.5

35.1

35.4

33.1

32.3

Chronic environmental hazard

6.6

6.2

6.4

5.6

6.2

6.3

6.5

6.0

6.0

6.7

Significant acute environmental hazard

25.8

26.1

23.2

21.7

24.5

23.0

21.6

21.0

20.6

21.4

Hundreds of millions of tons of hazardous substances are produced and consumed on an annual basis at EU 28 level only (Table 1), the most critical being the chronic, mutagenic and reprotoxic (CMR) substances (37 million tons/year), chronic toxic substances (20 million tons/year) and very toxic substances (43 million tons/year). Based on their structure and bio-availability, some of these compounds can be biodegraded and diluted by the aquatic environment, while others have more stable molecules and can be adsorbed on detritus or sediment particles, increasing the chances to be ingested by aquatic organisms and introduced to the food webs. Here, they can be stored in different organs or tissues (gills, liver, kidney, muscles), being subject to bioaccumulation or biomagnification within the food webs. This is how some of the hazardous substances not only induce sub- lethal effects on aquatic organisms, such as feminization of male fish, endocrine disruption, ill effects on health, growth rate, reproduction success, feeding rate, parental care, predator avoidance, schooling and shelter seeking (Brodln et al. 2014), their DNA structure or the health of their offspring, but can also reach alarming concentrations in higher trophic levels, also posing potential risks to human health.

Of the emergent pollutants, pharmaceuticals are of the highest concern, in particular due to their possible cumulative impact on aquatic biota and human health. Several hundred thousand tons of pharmacologically active substances are estimated to be used yearly for the treatment of human and animal diseases, including livestock and aquaculture (Kümmerer 2010), most of them reaching the aquatic environment. The increased use of antibiotics in human and veterinary medicine is already reflected at human health level, either by the increased incidence of allergies and antibiotic resistant bacteria, or as a result of their transfer with drinking water or vegetal food (Bouki et al. 2013, Kabir et al. 2015) or by possible genomic injuries of DNA (Li et al. 2007). Anti-inflammatory drugs are another highly problematic group: e.g. 10 pg/1 diclofenac affects aquatic microbial communities (Dorne et al. 2007), while experiments on its accumulation in rainbow trout have shown a bioconcentration factor (BCF) ranging between 12-2732 in liver, 5-971 in kidney, 3-763 in gills, and 0.3-69 in muscles, depending on the applied concentrations (Schwaiger et al. 2004).

The same substance has proved to have a catastrophic impact on 3 eagle species in India and Pakistan, as the birds feed on carcasses of cattle treated with diclofenac, and even doses as low as 7 pg/kg lead to the eagles’ death (Dorne et al. 2007). Endocrine disrupters such as PCBs, dioxins, perfluorinated compounds, DDT are also of high concern, as they can get into the human body by direct