Thesis (M.Sc. (Zoology)) --University Limpopo, 2013 / Major anthropogenic activities such as, mining, coal-fired power stations and intensive agricultural practices in the upper catchment area of the Olifants River, have a dramatic impact on the water quality downstream. As a result the river is presently the third most polluted river in South Africa. The aim of this study was to assess the impact of water and sediment quality on the health of Labeo rosae and Schilbe intermedius. The aim was accomplished by applying the Fish Health Assessment Index (HAI) which includes the Parasite Index (PI) at Flag Boshielo Dam in the Middle Olifants River, Limpopo Province. This was achieved through; assessing the water quality of the dam by determining the levels of physical and chemical constituents in the water at three sampling sites, determining the bioaccumulation of selected metals in the muscle tissue of the two fish species, assessing the fish health (including the fish condition factor) and the fish parasites in the dam by using the fish HAI and PI, and ascertaining the Human Health risk factor upon consumption of fish contaminated with metals from the dam. The water and sediment quality were seasonally sampled at three sites in the dam: inflow, middle and wall. Dorsal muscle tissues from both fish species were collected for metal bioaccumulation analyses. The water, sediment and fish muscle tissue samples were analysed by an accredited laboratory by means of ICP-OES spectrometry. For the fish health and parasites, ten fish per species were collected seasonally (July 2009 to April 2010) by means of gill nets and examined at a field laboratory using the HAI and PI protocol. Generally the water quality of Flag Boshielo Dam was acceptable for aquatic ecosystems according to the SAWQG with the exception of phosphorus and some metals at the inflow area. The pH ranged between slightly acidic to alkaline values; water temperature: 15°C to 26°C; water hardness medium soft, salinity within the freshwater range; turbidity in the clear water range. The TDS and major ions (salts) were acceptable for the duration of the study. The highest concentrations of nutrients (specifically phosphorus) as well as metals (aluminium, cadmium, copper, iron and lead) were recorded at the inflow area of the dam. The nutrients were very low except the eutrophic range phosphorus concentrations recorded at the inflow whereby, the Elands River may be an additional source of nutrients into Flag Boshielo Dam. The metals that were recorded above TWQR are; aluminium, cadmium, copper, iron and lead, of which were mostly recorded at the inflow. However, statistically there was no significant difference among the three sampling sites. The metal concentrations at the inflow were recorded only slightly higher than the middle and the dam wall. The main source of the metals may be the water coming from catchment area of the dam given the intensive agricultural activities taking place between Loskop Dam and Flag Boshielo Dam. Sediment and bioaccumulation: All the metals were recorded at higher concentrations in the sediment than in the water and fish muscle tissue, except antimony, selenium and strontium. The most abundant metals recorded in the sediment were iron and aluminium. However, the concentrations above the TEL were cadmium, nickel and zinc. The elevated metal concentrations in the sediment are indicating that the metal load in the sediment of Flag Boshielo Dam could be a potential risk for the aquatic biota if they become bioavailable. Antimony, selenium and strontium metal concentrations were recorded at higher concentrations in the muscle tissue of both fish species than in the sediment and water. Iron was the most accumulated metal in the muscle tissue of both fish species. In terms of numbers, more metals were recorded in the muscle tissue of S. intermedius than in L. rosae however the metal concentrations were higher in the latter. This can be attributed to their different trophic levels in the food chain; L. rosae is a primary consumer while S. intermedius is a tertiary consumer. However, the metals that accumulated in the fish muscle tissue were indicative of bio-availability of the toxic metals in the dam and not water/sediment pollution. According to a Human Health risk assessment (Chapter 3), metals that may have risks upon consumption of L. rosae are; antimony, arsenic, chromium, iron and vanadium; for S. intermedius are; antimony, chromium, iron, vanadium and arsenic (in descending order). These metals may pose toxic and carcinogenic risks to humans. Therefore, the rednose labeo (L. rosae) and to a lesser extend the silver catfish (S. intermedius) fish species from Flag Boshielo Dam may not be suitable for humans if consumed above 350 g per week. Fish health and parasites: The Health Assessment Index (HAI) values of the two fish species differed significantly with higher index values recorded for S. intermedius than L. rosae. Besides the Parasite Index (PI), abnormal haematocrit readings, liver conditions, skin lesions and clubbed gills are the necropsy anomalies that contributed predominantly to the HAI. Overall, the PI contributed mostly to the total HAI value. The parasite load and therefore also the mean intensity, mean abundance and prevalence of S. intermedius were higher during all seasons than that of L. rosae. The dominant ectoparasites for both species were from the Class Monogenea and the dominant endoparasites were nematodes. Out of 40 L. rosae sampled, 139 parasites were retrieved; five parasite species were ectoparasites and two endoparasites. From the 40 S. intermedius sampled, 2473 parasites were retrieved, from which two species (one genus) were ectoparasites and three species were endoparasites. The condition factor is used to compare the “condition”, “fatness” or wellbeing of fish and it is based on the hypothesis that heavier fish of a particular length are in a better physiological condition. The L. rosae had a better condition factor, recorded at values less than (2) as compared to S. intermedius (>2). The cause of the HAI necropsy anomalies may have been also from parasite load other than the metals in the water and sediment. However, the HAI alone cannot be used for metal pollution, unless it is done in conjunction with a histopathological study of the tissues/organs. Therefore, the cause of the recorded anomalies from both fish species is inconclusive. On the hand, fish can be used as bioindicators because the accumulated metals in the fish tissues are indicative of the bioavailability of metals in Flag Boshielo Dam.

Magistro darbe atlikta birių medžiagų barstymo proceso mokslinių darbų analizė. Apžvelgta Lietuvos kelius, žiemos metu, prižiūrinčių įmonių struktūra ir gamybinės sąlygos, įvertinant cheminių medžiagų barstymo proceso etapus, eiliškumą ir apimtis. Sudarytas barstytuvų technologinio proceso matematinis modelis, atliktas smėlio – druskos barstytuvų technologinio proceso kokybės tyrimas. Pasiūlyta eksperimentinė įranga ir eksperimento atlikimo metodika barstytuvų technologinio proceso kokybei įvertinti. / In this master work was reviewed analysis of spreading process. Reviewed the structure and industrial conditions of companie’s what during winter time are maintaining Lithuanian roads including the stages, priority and size of spreading process. Created mathematical model of spreading process and investigated the research of sand and salt spreader technological process. Suggested the experimental equipment and method to measure the quality of salt and sand spreading technological process.

Magistro darbe tiriame ąžuolo žėlimą ir jį lemiančius veiksnius. Darbo objektas – Kėdainių miškų urėdijos, Pašušvio girininkijos ąžuolo žėlimo intensyvumas ir jį lemiantys veiksniai mišriuose ąžuolo - minkštųjų lapuočių medynuose. Darbo tikslas – Ištirti ąžuolo žėlimo intensyvumą ir jį lemiančius veiksnius mišriuose ąžuolo - minkštųjų lapuočių medynuose. Darbo metodai: Tyrimai susidėjo iš dviejų etapų: girininkijos taksoraščių analizės ir tyrimo natūroje. Girininkijos taksoraščių analizė: iš girininkijos taksoraščių buvo išrinkti visi brandūs medynai pasiekę žemutinę IV grupės miškams nustatytą kirtimo amžių ir turintys pomiškio sudėtyje bent 1 ąžuolo dalį. Po to surinkta informacija apie savaiminį ąžuolo žėlimą priklausomai nuo ąžuolo kiekio medyno sudėtyje, medyno amžiaus, skalsumo, atskirai nurodant bendrą pomiškio kiekį ir atskirai ąžuoliukų kiekį juose. Medyno amžius buvo grupuojamas: 40-60; 60-80; 80-100; 100-120; 120 ir > metų Medyno sudėtis buvo grupuojama: 1-2; 3-4; 5-6; 7-8; 8-10 ąžuolų Pomiškio kieks buvo grupuojamas: 0-0,9; 1,0-1,9; 2,0-2,9; 3,0-3,9; 4,0-4,9; 5,0 ir > tukst. / ha. Girininkijos miškotvarkos medžiagos analizės metu iš viso buvo išrinkti 1956 taksaciniai sklypai. Buvo rasti 28 taksaciniai sklypai kurių pomiškio sudėtyje yra savaiminio ąžuolo. Kameralinių darbų metu buvo nustatinėjami ryšiai tarp medynų sudėties, skalsumo ir augavietės sąlygų, ąžuoliukų pomiškio kiekio. Tyrimai natūroje: atlikdami tyrimus natūroje tyrėme ąžuoliukų skaičiaus... [toliau žr. visą tekstą] / Master paper researches the sprout of oak and the factors determining it. Object of the paper - an intensity of sprout of Pasusvis forestry oak at Kedainiai forests enterprise and the factors determining it at mixed arboretums of oaks- soft leafy trees. Goal of the paper - to survey an intensity of sprout of the oak and the factors determining it at mixed arboretums of oaks- soft leafy trees. Methods of work: The researches consist of two stages: the analysis of forestry valuation register and the research in reality. Analysis of forestry valuation register: all mature arboretums that have reached bottom age set for deforesting of 4th group forest and having at least 1 part of oak at their compositions were selected from the forestry valuation register. Then the information regarding self-sprout of the oak depending on quantity of oaks at the composition of arboretum, age of arboretum, abundance were collected by separately indicating general quantity of undergrowth and the number of oaks in it. The age of arboretum was grouped: 40-60; 60-80; 80-100; 100-120; 120 and > years The composition of arboretum was grouped: 1-2; 3-4; 5-6; 7-8; 8-10 oaks The quantity of undergrowth was grouped: 0-0,9; 1,0-1,9; 2,0-2,9; 3,0-3,9; 4,0-4,9; 5,0 and > thousand. / ha. During an analysis of forestry forest management material, 1956 forest valuation lots were selected. There were 28 forest valuation lots found, whose undergrowth composition contained spontaneous oak. During soil research... [to full text]

In the years 2005-2006 it was practised the analysis of plant production and the evaluation of typological structure of selected grasslands in selected farming business. It were evaluated the gualitative indices of produced roughage. It were evaluated the area sof annual crops, multi-annual fodder crops and of permanent grasslands and the produce of fodder of fodder crops and the sort and categories of stock cattle.