WATER QUALITY SURVEY OF STREAMS FROM RETEZAT MOUNTAINS (ROMANIA) [310493]

WATER QUALITY SURVEY OF STREAMS FROM RETEZAT MOUNTAINS (ROMANIA)

Mihai-Cosmin Pascariu1,2, Tiberiu Tulucan3,4, Mircea Niculescu5, Iuliana Sebarchievici2, Mariana Nela Ștefănuț2*

1 “Vasile Goldiș” [anonimizat], 86 [anonimizat]-310045, Arad, Romania

2 National Institute of Research & [anonimizat], 144 Dr. [anonimizat], RO-300569, Timișoara, Romania

3 “Vasile Goldiș” [anonimizat]-Moneasa Center of Ecological Monitoring, 94 Revoluției Blvd., RO-310025, Arad, Romania

4 [anonimizat], 2B [anonimizat]-310422, Arad, Romania

5 [anonimizat], 6 Vasile Pârvan Blvd., RO-300223, Timișoara, Romania

*Corresponding author, e-mail: [anonimizat], tel.: +[anonimizat], fax: +[anonimizat]

[anonimizat], [anonimizat]. In this study a number of samples from creeks located in the Southern Retezat (Piule-Iorgovanul Mountains) between 1529 and 1871 m [anonimizat] a few heavy metals. Additionally, [anonimizat], [anonimizat], cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead and zinc. The measured contents were compared with the European Union and Romanian standards regarding drinking water and surface water quality. A [anonimizat]. The studied heavy metals have been found to be in very low concentrations or under the method’s detection limit. Thus, [anonimizat], [anonimizat]. Also, no other potential sources of chemical pollution have been identified in the studied perimeter during our survey.

Keywords: [anonimizat], [anonimizat]-AES, [anonimizat] (Romania, Hunedoara County), [anonimizat] a high biological value and has thus been added to the UNESCO Man & Biosphere Reserves network. The park includes 19 peaks above 2000 m elevation and it has been proposed as a model for the conservation efforts in Romania and other countries (Bytnerowicz et al. 2005).

While several studies from the scientific mainstream literature have dealt with the geology and hydrogeology of the area (Povară and Ponta 2010) or the composition of mountain lake sediments (Catalan 2015; Camarero et al. 2009; Rose et al. 2009), [anonimizat].

[anonimizat] (cations and anions). The tested cations include ammonium (NH4+), arsenic (As3+), calcium (Ca2+), iron (Fe2+/Fe3+) and other heavy metals (e.g., lead Pb2+), while the anions that were searched for include halides (chloride Clˉ, bromide Brˉ, iodide Iˉ), nitrite (NO2ˉ) and sulfate (SO42ˉ), all of them being determined according to the chemical methods stipulated in the Romanian Pharmacopoeia (1993) or by using test strips. The results were supplemented by microwave plasma – atomic emission spectrometry (MP-AES) determinations for some metals, i.e. aluminium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, lead and zinc. Most of them are included in the category of heavy metals (Duffus 2002), which are considered common pollutants of the environment, having both natural and anthropogenic origins. Heavy metals can form highly toxic compounds which, when inhaled or ingested, can have an impact on almost every organ and system in a living organism, posing a danger to the stability of the ecosystems and also a risk for the human health (Bradl et al. 2005).

STUDY AREA

The studied area (Fig. 1) belongs to the southern part of the Retezat Mountains (Bytnerowicz et al. 2005), also known as Southern Retezat (Retezatul Sudic, in Romanian). The researched space is located on the southern slope of the Piule-Iorgovanu Mountains (Ardelean 2010; Povară and Ponta 2010), between 1529 and 1871 m of altitude. The stream water samples were collected from point sources located in the upper part of the Jiul de Vest River basin (Iordache et al. 2015; Ujvári 1972), upstream from Câmpu Mielului, from its left tributaries Scorota cu Apă and Scorota Seacă. The sampling points were allocated by considering the short lengths of the active sections that form their higher basin. The microbasins corresponding to the sampling points contain active segments with lengths which vary between 100 and 500 m, while the flow of the studied creeks is usually between 2 and 5 L/s. Also, the allocation of the sampling points regarded their relative position to the Scorota sheepfold: near the sheepfold, which is also the lowest part of the grazing area, and in the higher limit of this area, with ~100 m steps between the two altitudes.

From geological point of view, we mention the presence in the region of sedimentary rocks, like quartz sandstones, marl and marl-limestones, with patches of schists and limestones. Soils are represented by humus-iron-illuvial podzols, humus-silicate soils, brown podzols and brown acidic soils. These mountains are characterized by a rich flora and fauna. Subalpine meadows (grassland) predominate, being in contact with the upper limit of the coniferous domain, composed mainly of Norway spruce (Picea abies). Carex and Festuca meadows alternate with mountain pine, juniper shrubs and dwarf shrubs composed of Vaccinium vitis-idaea and Vaccinium myrtillus (Bytnerowicz et al. 2005; Kern and Popa 2009; Mâciu et al. 1982; Tulucan et al. 1999), as can be seen in Fig 2. The climate is continental and typical for high mountain areas (Povară and Ponta 2010). In the last week of October, prior to sampling, weather was generally stable, with clear sky or passing cirrostratus clouds, with constant atmospheric pressure and with slightly negative temperatures at night. There was no record of rainfall or snowfall that could have produced signs of indirect contamination.

The list of analyzed samples, together with time, location and on-site measured parameters, are given in Table 1. Samples 1-3 come from springs which originate in detrital sediments from non-karst rocks (sandstones). Sample 4 comes from a spring localized in non-calcareous detrital rocks. Samples 5 and 6 were collected near Scorota sheepfold from two creeks that flow over Holocene detrital deposits. The springs are located in the river bed deposits or at the base of the erosion regressive step. Although they can be classified as slope springs, they are not generated by an obvious stream (concentrated hydrographic network). Instead, they constitute some emergences at the contacts between superficial deposits of consolidated sedimentary rocks, which are fixed in place by soils and vegetation. The catchment is located in the Festuca meadows perimeter. Sampling sites corresponding to samples 1-3, 5 and 6 are located in the juniper floor, where juniper clusters alternate with Festuca meadows. For samples 2 and 3, the measurements were taken near a confluence of two rivulets, tributaries of Scorota cu Apă stream: sample 2 comes from the right tributary, while sample 3 comes from the left tributary. Regarding the highest measured point, corresponding to sample 4, the sampling was done in a ravine with the mountainsides heavily eroded by the rain erosion (Fig. 2, right).

METHODS

Sampling and in situ measurements

Geographic coordinates and altitudes were established using a Magellan Meridian Platinum Mapping GPS receiver, while air temperature and pressure were recorded with a portable Auriol weather station.

Sample temperature, pH and electrical conductivity (EC) were registered with a portable Hanna HI 98130 Combo pH&EC measuring device. Nitrites and sulfates were measured in situ using Merck test strips (Merckoquant® Nitrit-Test and Merckoquant® Sulfat-Test).

We have generally followed ISO 5667-3 guidelines for sampling. To prevent contaminations, thoroughly cleaned plastic recipients were used (Bradl et al. 2005; Ogoyi et al. 2011), prepared in the laboratory by protracted soaking with 2 M nitric acid followed by rinsing with double distilled water. They were also conditioned in situ with several aliquots of the water to be sampled. After completing this protocol a volume of 350 mL of water was collected. To avoid the loss of elements by adsorption on the walls of the storage recipients, the samples were stabilized by acidification to pH ~ 1 by adding 20 mL of 10% nitric acid (Pascariu et al. 2013).

Laboratory analysis

All glassware needed for analysis was washed with 2 M nitric acid and thoroughly rinsed with double distilled water just prior of being used. Preliminary analyses were performed on filtrated samples the day after they were collected according to the general procedures stated by the Romanian Pharmacopoeia (1993). A blank solution (350 mL double distilled water with 20 mL 10% nitric acid) was also prepared in an identical plastic container and tested for comparison. The following aqueous reagents were used: Nessler’s reagent (potassium tetraiodomercurate(II), K2HgI4, and potassium hydroxide, KOH) for ammonium, sodium hypophosphite (NaH2PO2) in hydrochloric acid (HCl) for arsenic, ammonium oxalate ((NH4)2C2O4) for calcium, silver(I) nitrate (AgNO3) for halides, potassium hexacyanoferrate(II) (K4[Fe(CN)6]) for iron, sodium sulfide (Na2S) for heavy metals (e.g., lead) and barium chloride (BaCl2) for sulfates. The chemical reactions that use these reagents are stated to have the following detection limits: 0.3 ppm for ammonium, 1 ppm for arsenic, 3.5 ppm for calcium, 0.5 ppm for chlorides, 0.5 ppm for iron, 0.5 ppm for lead and 3 ppm for sulfates (Romanian Pharmacopoeia 1993).

For MP-AES, an Agilent 4100 with web-integrated Agilent MP Expert software was used. The instrument was adjusted using as calibration standard the provided Wavelength Calibration Concentrate for ICP-OES & MP-AES (Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr, Zn 50 mg/L, K 500 mg/L) and also an AAS standard solution for Ca, Fe and Mg. The following wavelengths (in nm) were measured: Al 396.152, Cd 228.802, Co 340.512, Cr 425.433, Cu 324.754, Fe 259.940, Mn 403.076, Mg 285.213, Mo 379.825, Ni 352.454, Pb 405.781, and Zn 213.857. In contrast to atomic absorption spectrometry (AAS), which is based upon the absorption of a characteristic radiation, atomic emission spectrometry (AES) uses the emission of a characteristic wavelength for the determination of the analyte element. Plasma emission spectrometry utilizes a plasma as the excitation source for atomic emissions, which, in MP-AES, is formed via the use of a microwave field source. AES belongs to the most useful and commonly used techniques for the analysis of heavy metals, providing rapid and sensitive results in a variety of sample matrices, although the detection limits are higher than those of AAS (Bradl et al. 2005; Higson 2006).

RESULTS AND DISCUSSION

Owing to the location of the sampling points and the time the samples were acquired, we can confidently state that the samples were not affected by any subterranean contributions, nor by any atmospheric precipitations. The surface flow was not influenced by the meteorological parameters regarding the weather conditions prior to the sampling period, and we did not find evidence of any disturbances, either geological or hydrogeological. Also, due to the fact that the sampling was performed at the beginning of November, any organic pollution that might have appeared because of grazing should have been washed by precipitations in the two months that have passed since the ending of the grazing period.

The in situ tests using test strips did not indicate the presence of nitrites or sulfates (nitrite ion concentration less than 1 mg/L, sulfate ion concentration less than 200 mg/L, according to test strips instructions). Also, the very low measured EC indicates that the total dissolved solids (TDS) must be under 10 ppm (Lenntech 2016).

The preliminary chemical analyses were performed in the laboratory using the procedures outlined in the Romanian Pharmacopoeia (1993). The samples were tested for the presence of ammonium, arsenic, calcium, halides (chloride, bromide, and iodide), iron, heavy metals (e.g., lead) and sulfates. Except for a very faint opalescence obtained when sample 1 was tested for calcium, all these tests were negative, an observation that supports the very low measured EC for all samples (Table 1).

MP-AES results are summarized in Table 2, while the drinking water standards from EU (1998) and Romanian “Law no. 311 from June 28, 2004” (Romanian Government 2004) are given in Table 3 for comparison with the analyzed samples. As can be seen, except for a somewhat increased iron content in sample 1 (probably due to the humus-iron-illuvial podzols, which are present in the area), the studied streams seem to be within the limits specified for drinking water (Brad et al. 2015) by all specified standards.

The Romanian environmental legislation regarding surface water quality, stipulated in “Order no. 161 from February 16, 2006” (Romanian Government 2006), is summarized for the considered ions in Table 4. According to Table 4, the last four sampled streams seem to belong to class I. An exception could be the stream that provided the first sample which could belong to class IV according to the iron content. Also, according to the lead content, the streams that provided the first two samples could belong to class II or III, but these low measured lead levels may more realistically be accounted for by the MP-AES precision limit.

Our findings support the previous studies which state that the Retezat Mountains are among the least contaminated regions in Europe (Catalan 2015, Catalan et al. 2009).

CONCLUSIONS

A modern physical-chemical method, namely MP-AES, alongside some classical analytical procedures also applied in the Romanian Pharmacopoeia, were used to analyze a few springs and creeks from the Retezat National Park. Fortunately, for all tested samples, heavy metals were at very low levels or under the detection limit for the chemical reactions employed and the MP-AES method applied. From this point of view, the samples comply as drinking water according to the EU and Romanian recommendations. The average water temperature was 5.0 °C, the mean pH value was 8.11, while the measured EC value was around or below 10 μS/cm for all samples, the later also confirming the very small ion content present in the analyzed mountain streams. In the microbasin corresponding to the sampling points, there seems to be no heavy metal pollution. Also, no other potential sources of chemical pollution was recorded in the studied perimeter during our survey.

Acknowledgements

Part of this paper was presented at The 17th DKMT Euroregional Conference on Environment and Health, June 5-6, 2015, Szeged, Hungary. Some of the research was done at the Center of Genomic Medicine of the “Victor Babeș” University of Medicine and Pharmacy of Timișoara, POSCCE 185/48749, contract 677/09.04.2015.

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Fig. 1 Location of the sampling points (Google Earth 2015)

Fig. 2 Surroundings of the sampling sites

Table 1 Sampling parameters

a geographic coordinates and altitude were established using Google Earth (2015) software;

b not measured.

Table 2 MP-AES cation content results, in mg/L

* under detection limit (< 0.005 mg/L).

Table 3 Drinking water standards comparative table; all values are in units of mg/L unless stated otherwise (European Union 1998; Romanian Government 2004)

# not mentioned;

* is allowed as 2.0 mg/L if the distribution piping material contains copper.

Table 4 Surface water quality classes depending on cation content, as stated in Romanian “Order no. 161 from February 16, 2006”; units are in mg/L, unless stated otherwise