No abstract

During experiment, fish were exposed to a heavy metal model mixture (Cu, Zn, Ni, Cr, Pb, Cd) for 14 days. Heavy metal concentrations corresponded to Maximum Permitted Concentrations (MPC) in surface waters. The amount of heavy metals in fish tissues was determined using atomic absorption spectrophotometry (AAS). Though both investigated fish species accumulated heavy metals with similar general intensity, the stone loach did it in the sequence gills > liver > muscle, and the rainbow trout ‐ conversely: muscle > liver > gills. Ni concentration in the stone loach muscle made 0.607 mg/kg and Pb concentration was 0.21 mg/kg, whereas Cd concentration in the rainbow trout muscle reached 0.45 mg/kg and exceeded the MPC indicated in the Lithuanian hygiene standard. These results coincide with the data of the heavy metal research into fish species from natural water bodies. Pb and Cd concentrations in fish tissues are the highest and frequently exceed the MPC. These findings urge for the constant control of the amount of heavy metals in fish. Santrauka Bandomosios žuvys 14 paru buvo veikiamos modeliniu sunkiuju metalu mišiniu (Cu, Zn, Ni, Cr, Pb, Cd). Metalu koncentracijos atitiko ju didžiausias leidžiamas koncentracijas (DLK) paviršiniuose vandenyse. Sunkiuju metalu kiekis audiniuose buvo nustatomas atomines absorbcijos spektrofotometriniu (AAS) būdu. Nors abieju tirtu rūšiu žuvu audiniuose sunkieji metalai kaupesi vienodu intensyvumu, šlyžio audiniuose jie kaupesi tokiu eiliškumu: žiaunos > kepenys > raumenys, o vaivorykštinio upetakio ‐ atvirkščiai: raumenys > kepenys > žiaunos. Šlyžio raumenyse Ni koncentracija buvo 0,607 mg/kg, o Pb ‐ 0,21 mg/kg ,vaivorykštinio upetakio raumenyse Cd koncentracija sieke 0,45 mg/kg ir viršijo Lietuvos higienos normoje nurodytaja DLK. Šie rezultatai sutampa su sunkiuju metalu nuolatines stebesenos kontroliuojamu rūšiu žuvyse iš natūraliu vandens telkiniu tyrimu duomenimis. Žuvu audiniuose Pb ir Cd koncentracijos yra didžiausios ir dažnai viršija DLK. Tokie rezultatai ipareigoja nuolat kontroliuoti sunkiuju metalu kieki žuvyse. Резюме Подопытные рыбы в течение 14 суток подвергались воздействию смеси тяжёлых металлов (Cu, Zn, Ni, Cr, Pb, Cd) в предельно допустимых концентрациях (ПДК), предусмотренных для внутренних водоёмов. Количество тяжелых металлов в тканях рыб устанавливали при помощи атомной абсорбции спектрофотометрическим методом. Несмотря на то, что оба вида рыб накапливали металлы с одинаковой общей интенсивностью, голец их накапливал в следующей последовательности: жабры > печень> мышцы, а радужная форель – наоборот: мышцы > печень> жабры. В мышцах гольца концентрация Ni составила 0,607 мг/кг, Pb – 0,21 мг/кг, а в тканях форели концентрация Cd составила 0,45 мг/кг и превышала ПДК. Экспериментальные данные совпадают с данными, полученными в мониторинговых водоемах. Установлено также, что концентрация Pb и Cd в тканях зачастую прeвышаeт ПДК. Полученные результаты обязывают постоянно контролировать уровень тяжелых металлов в тканях рыб.

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and elevation of the introduced bacterial strains throughout the experiment. Reference to this paper should be made as follows: Nõ lvak, H.; Truu, J.; Limane, B.; Truu, M.; Cepurnieks, G.; Bartkevičs, V.; Juhanson, J.; Muter, O. 2013. Microbial community changes in TNT spiked soil bioremediation trial using biostimulation, phytoremediation and bioaugmentation, Journal of Environmental Engineering and Landscape Management 21(3): 153Á162. http://dx.

Journal of Environmental Engineering and Landscape ManagementPublication details, including instructions for authors and subscription information:Abstract. Now, it is normally agreed that noise barriers -shields with appropriate devices on the top edge -limit the diffraction of sound waves more effectively than the usual shields of the equal or in some cases even greater height. These barriers are referred to as "edge-modified" noise shields. The article describes acoustic field researches that estimate the impact of the slope of the upper edge of the noise barrier on the effectiveness of shielding from environmental noise. The article was drafted on the basis of methodical recommendations presented in the standard ISO 11821: 1997 "Acoustics -Measurement of the in situ sound attenuation of a removable screen". While altering the slope angle, respectively to 90°, 120°, 150°, 180°, different noise barriers were formed: "L90" (slope angle 90°), "J120", "J150" (slope angles 120° and 150°), and the usual "straight type" (slope angle 180°). The impact made by the form of the noise barrier on the spread of noise in the noise suppression area was observed at the areas of low (100-315 Hz) and high (2000-5000 Hz) frequency. The most effective form of a barrier in reducing the diffraction of low frequency sound waves was "J120", whereas high frequency sound waves were most effectively reduced using a usual straight noise barrier.

Experimental investigations into acoustic properties of building materials and structures manufactured thereof were conducted in a noise-suppression chamber. A study was made of the noise-suppression efficiency of scrap-tires of different crumb rubber, using the source of constant noise from loudspeakers "Bruel&Kjaer". For experiments, crumb rubber of 3 different sizes was used: crumb rubber I with the size of 0.5-1 mm, II -4 mm, and III -6 mm. Scrap-tire crumb rubber was placed into the samples of experimental structures of different thickness (50 mm, 100 mm, 150 mm and 200 mm). The experimental investigation results show that the coarsest crumb rubber (6 mm) is most efficient in suppressing low-frequency sounds (up to 300 Hz), when noise level reduction gets changed in the range of 31-35 dB, depending on the samples of the experimental structure. High-frequency sounds (over 800 Hz) are most efficiently suppressed by the finest scrap-tire crumb rubber (0.5-1 mm), noise level reduction changes from 53 dB to 64 dB.