G L O B A L S Y M P O S I U MO N S O I L

P O L L U T I O N2 - 4 M A Y 2 0 1 8 | F A O - R O M E , I T A L Y

Assessment of ecological state of halogenic technosoils in the former well drilling site

using biological indicatorsOksana Naidonova1, Mykola Zhuravel2

1NSC ‘Institute for Soil Science and Agrochemistry Researchnamed after O.N. Sokolovsky’; 2Northeastern Scientifi c Center ‘Intellect Service Ltd.’

INTRODUCTION

Microbiological and biochemical indicators are sensitive to chang-es in soil properties which have undergone pollution, in particular, with oil, heavy metals, drilling fluid or mud components, saline produced waters, etc. For the sta-tus assessment of contaminated and reclaimed soils, the most sen-sitive and universal indicators are the number of microorganisms belonging to the main ecological, trophic and taxonomic groups and soil enzymatic activity.

OBJECTIVES

To identify changes in microbial community condition of dark grey soil under their pollution with

saline produced waters. To deter-mine the direction and estimate the degree of change in biological properties of halogenic technozems under influence of salinization and pollution with saline waters.

METHODOLOGY

Microbiological research was car-ried out in soil samples taken in September 2017 from a layer of 0-25 cm at eight points on the ter-ritory of the explored borehole num-ber 6 of the Svyrydivske gas con-densate field Poltava region (Ukraine) and two points of the background soil. The locations of the sampling points are shown in Fig. 1. In 2016, an emergency occurred near the borehole, a pipe-line flood. The picture shows the

salt spot formed as a result of the leakage of saline produced water. We determined number of soil microorganisms by sowing dilu-tions of soil suspensions on dense nutrient media. Soil enzymatic activity was determined by the pho-to-electrocolorimetric method.

MAIN RESULTS

At points 6-03, 6-04 and 6-08 within the drilling well technosoils territory, deviations of the number of microorganisms of certain groups in the unfavorable direc-tion (Table 1), decrease in the activ-ity of soil enzymes (Table 2) have been detected. According to Sum-mary Biological Index (SBI) and Biological Degradation Index (BDI) values, a strong degree of biologi-

cal degradation of the soil is deter-mined at points 6-03, 6-04 and 6-08 (BDI are respectively -52, -62 and -71 %). At the point number 6-05 a weak degree was detected (BDI = -13), and at the point 6-07 the average degree of soil degrada-tion (BDI = -27) . Soils at points 6-06, 6-09 and 6-10 can be con-sidered non-degraded.

CONCLUSION

The biological indicators used in this study should be included in the system of indicators of envi-ronmental monitoring of polluted soils, including in oil and gas pro-ducing areas. Мicrobiological & biochemscal indicators are highly informative and adequately reflect the condition of contaminated soils.

Fig. 2:The oligotrophs on

starvation agar (SA)

Point 6-04 Background 2 (6-Fon-2)

Point 6-04 Background 2 (6-Fon-2)

Fig. 1:The points of sampling at the site of the well number 6

Sampling points

Nitrogen assimilating

microorganisms, mln. CFU/g

Actino-myces,

mln. CFU/g

Fungi, th.

CFU/g

Olygo-trophs,

mln. CFU/g

Eutrophs, mln.

CFU/g

Indices

SBI, %

BDI, %

organic mineral6-03 21.40 5.65 2.43 32.88 6.82 32.51 39 -526-04 19.87 2.54 1.68 44.20 6.22 24.13 32 -626-05 21.44 17.81 7.02 128.50 24.41 46.43 78 -136-06 27.46 14.12 6.42 347.16 27.89 48.35 82 06-07 12.58 7.32 5.34 83.95 25.78 25.32 54 -276-08 3.69 5.03 2.36 29.64 7.70 11.11 21 -716-09 11.29 14.49 10.15 88.26 34.72 36.02 77 06-10 17.20 20.08 5.10 80.30 31.16 42.46 81 0

Average 16.87 10.88 5.06 104.36 20.59 33.29 58 -22Background 1 32.99 9.26 5.65 180.53 25.44 46.66 77 0Background 2 29.81 11.13 6.12 29.65 25.75 47.09 78 0

Average 31.40 10.20 5.89 105.09 25.60 46.88 78 0LSD0,05 2.04 2.10 1,06 7,96 4.22 32.51 – –

Table 1: The number of microorganisms of the main ecological-functional, trophic and taxonomic in the soil territory hole number 6 and background soil

Sampling points

Dehydrogenase, mg TPF/100 g per 24 hours

Invertase, mg glucose/g per 24 hours

Polyphenol oxidase, mg 1,4-n-benzoquinone/10 g

per 1 hours 6-03 88.00 5.75 594.006-04 82.50 5.33 638.006-05 118.25 5.24 902.006-06 129.25 7.34 1122.006-07 140.25 7.07 1100.006-08 116.80 7.30 1166.006-09 107.25 7.21 1012.006-10 96.25 6.61 902.00

Average 109.82 6.46 929.50Background 1 97.60 5.97 858.00Background 2 96.25 6.15 770.00

Average 96.93 6.06 814.00LSD0,05 6.90 0.18 32.00

Table 2: Enzymatic activity of polluteded soil of territory well number 6 and background soil