Procedures for Removal of Pesticides from the Environment

Organoklorni i organofosforni pesticidi se u velikim količinama upotrebljavaju u proizvodnji hrane zbog svoje učinkovitosti i niske cijene i smatra se da danas na svjetskom tržištu postoji oko 1500 aktivnih tvari s pesticidnim učinkom. Ovi postojani organski onečišćivači dugo nakon primjene mogu zaostajati u tlu, mulju i sedimentima ili ući u vodene tokove, te dospjeti izravno u prehrambeni lanac. Danas se za uklanjanja pesticida s onečišćenih lokacija primjenjuju sljedeći postupci: niskotemperaturna toplinska desorpcija, spaljivanje, bioremedijacija i fitoremedijacija. Svaka od tehnologija ima svoje prednosti i nedostatke. U konačnici idealan proces remedijacije bio bi takav da u potpunosti razgradi onečišćivač bez stvaranja međuprodukata. Neki od procesa imaju samo sposobnost razmještanja i stabilizacije onečišćivača, no ne postižu potpuno uklanjanje. Niskotemperaturna toplinska desorpcija je tehnologija čišćenja ex situ najčešće primjenjivana za uklanjanje pesticida. Prednost primjene spaljivanja je potpuno uklanjanje onečišćivača, međutim proces je skup jer zahtijeva transport medija do spalionice. Procesi bioremedijacije potaknuti su prirodnim procesom mikrobiološke razgradnje onečišćivača odnosno interakcijom mikroorganizama i komponenata otpada. Postupak ex situ uključuje upotrebu bioreaktora. Jedan od postupaka je i postupak land spreading kod kojeg se onečišćeni medij miješa s tlom pri čemu autohtoni mikroorganizmi razaraju onečišćivače. Učinkovitost u biorazgradnji toksičnih onečišćivača utvrđena je za gljive bijelog truljenja, posebno iz roda Phanerochaete. Fitoremedijacija je tzv. "zelena tehnologija" primjenom biljaka, pri čemu biljke nisu izravno uključene u proces i služe kao katalizator za pojačavanje rasta i aktivnosti populacije mikroorganizama korijenja. U fitoremedijaciji pesticida najčešće se primjenjuju biljke roda Kochia, za koje je utvrđeno da zbog interakcija biljke i mikroorganizama iz područja rizosfere dolazi do razgradnje prisutnih pesticida. Bioremedijacija i fitoremedijacija su danas dvije nove metode koje se još procjenjuju. Brojnim laboratorijskim istraživanjima i pilot-studijama nastoji se povećati raspoloživost primjene bioremedijacije i fitoremedijacije te nadvladati ograničenja ovih metoda.Pesticides are widely used in food production, and it is believed that more than 1000 types of pesticides are in use. Organochlorines and organophosphorous pesticides are used in large quantities due to their efficacy and low cost. These persistent organic pollutants remain in the soil, silt, and sediment long after application, and enter into watercourses, finding their way directly into the food chain. Today, the following procedures are used to remove pesticides from polluted localities: low temperature thermal desorption, incineration, bioremediation and phytoremediation. Each of these technologies has its advantages and disadvantages. Ultimately, the ideal remediation process would be to completely destroy the pollutant without the production of byproducts. Some of these processes are only capable of moving and stabilizing the contaminant, but do not clean or fully eliminate the pollutant. Low temperature thermal desorption is an ex situ cleaning technology most often used to remove pesticides. The advantage of incineration is the complete elimination of the pollutant; however, this process is very expensive, as it requires transport of the media to the incinerator. The processes of bioremediation are stimulated by natural processes of microbiological degradation of contaminants through the interaction of microorganisms and nutrients from waste. Ex situ procedures include the use of bioreactors. Another procedure is land spreading, in which the contaminated medium is mixed with the soil, in which the native microorganisms degrade the pollutants. Efficacy in the biodegradation of toxic pollutants has been established for white root fungi, particularly those from the genus Phanerochaete. Phytoremediation is a green technology that uses plants, in which plants are not directly included in the process but serve as a catalyser for increasing the growth and activity of root microorganisms. In phytoremediation of pesticides, plants of the genus Kochia are often used, as it has been established that the interaction between the plants and microorganisms in the rhizosphere leads to the degradation of pesticides. Bioremediation and phytoremediation are two new methods that are still under assessment. Numerous laboratory studies and pilot studies are attempting to increase the applicable uses of bioremediation and phytoremediation, and overcome the limitations currently presented by these methods

Wild Boar Tissue Levels of Cadmium, Lead and Mercury in Seven Regions of Continental Croatia

Concentrations of cadmium, mercury and lead were analysed by atomic absorption spectrometry in the kidney and muscle of free-living wild boar (n = 169) from hunting grounds in seven counties of continental Croatia. Mean levels of metals (mg/kg) in muscle and kidney of boars ranged as follows: Cd: 0.005–0.016 and 0.866–4.58, Pb: 0.033–0.15 and 0.036–0.441, Hg: 0.004–0.012 and 0.04–0.152. In all seven regions, concentrations exceeded the permitted values (muscle and kidney mg/kg: cadmium 0.05/1; lead 0.1/0.5; mercury 0.03/0.1) in 13.6% and 71.6% of samples (muscle and kidney, respectively) for cadmium; 13.6% and 8.9% for lead; 19.5% and 2.4% for mercury. There were significant differences among the regions. Vukovar-Srijem and Virovitica-Podravina Counties were highly contaminated with cadmium, Sisak-Moslavina and Virovitica-Podravina Counties with lead and Brod-Posavina County had highest mercury concentrations. These results suggest a detailed investigation of physiological and environmental factors contributing to accumulation of metals in boars

One-loop corrections to a scalar field during inflation

The leading quantum correction to the power spectrum of a gravitationally-coupled light scalar field is calculated, assuming that it is generated during a phase of single-field, slow-roll inflation.Comment: 33 pages, uses feynmp.sty and ioplatex journal style. v2: matches version published in JCAP. v3: corrects sign error in Eq. (58). Corrects final coefficient of the logarithm in Eq. (105). Small corrections to discussion of divergences in 1-point function. Minor improvements to discussion of UV behaviour in Sec. 4.

One-loop corrections to the curvature perturbation from inflation

An estimate of the one-loop correction to the power spectrum of the primordial curvature perturbation is given, assuming it is generated during a phase of single-field, slow-roll inflation. The loop correction splits into two parts, which can be calculated separately: a purely quantum-mechanical contribution which is generated from the interference among quantized field modes around the time when they cross the horizon, and a classical contribution which comes from integrating the effect of field modes which have already passed far beyond the horizon. The loop correction contains logarithms which may invalidate the use of naive perturbation theory for cosmic microwave background (CMB) predictions when the scale associated with the CMB is exponentially different from the scale at which the fundamental theory which governs inflation is formulated.Comment: 28 pages, uses feynmp.sty and ioplatex journal style. v2: supersedes version published in JCAP. Some corrections and refinements to the discussion and conclusions. v3: Corrects misidentification of quantum correction with an IR effect. Improvements to the discussio