The primary aim of the present review on phenoxyalkanoic acid herbicides-2-(2,4-dichlorophenoxy) acetic acid (2,4-D), 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), (2R)-2-(2,4-dichlorophenoxy) propanoic acid (dichlorprop-P), (2R)-2-(4-chloro-2-methylphenoxy) propanoic acid (mecoprop-P), 4-(2,4-dichlorophenoxy) butanoic acid (2,4-DB), and 4-(4-chloro-2-methylphenoxy) butanoic acid (MCPB)-was to compare the extent of their adsorption in soils and degradation rates to assess their potential for groundwater contamination. The authors found that adsorption decreased in the sequence of 2,4-DB > 2,4-D > MCPA > dichlorprop-P > mecoprop-P. Herbicides are predominantly adsorbed as anions-on organic matter and through a water-bridging mechanism with adsorbed Fe cations-and their neutral forms are adsorbed mainly on organic matter. Adsorption of anions of 2,4-D, MCPA, dichlorprop-P, and mecoprop-P is inversely correlated with their lipophilicity values, and modeling of adsorption of the compounds based on this relationship is possible. The predominant dissipation mechanism of herbicides in soils is bacterial degradation. The contribution of other mechanisms, such as degradation by fungi, photodegradation, or volatilization from soils, is much smaller. The rate of bacterial degradation decreased in the following order: 2,4-D > MCPA > mecoprop-P > dichlorprop-P. It was found that 2,4-D and MCPA have the lowest potential for leaching into groundwater and that mecoprop-P and dichlorprop-P have slightly higher potential. Because of limited data on adsorption and degradation of 2,4-DB and MCPB, estimation of their leaching potential was not possible. Environ Toxicol Chem 2016;35:271-286. # 2015 SETAC

The article presents the behavior of phenoxy acids in water, the levels in aquatic ecosystems, and their transformations in the water environment. Phenoxy acids are highly soluble in water and weakly absorbed in soil. These highly mobile compounds are readily transported to surface and groundwater. Monitoring studies conducted in Europe and in other parts of the world indicate that the predominant phenoxy acids in the aquatic environment are mecoprop, 4-chloro-2-methylphenoxyacetic acid (MCPA), dichlorprop, 2,4-dichlorophenoxyacetic acid (2,4-D), and their metabolites which are chlorophenol derivatives. In water, the concentrations of phenoxy acids are effectively lowered by hydrolysis, biodegradation, and photodegradation, and a key role is played by microbial decomposition. This process is determined by the qualitative and quantitative composition of microorganisms, oxygen levels in water, and the properties and concentrations of phenoxy acids. In shallow and highly insolated waters, phenoxy acids can be decomposed mainly by photodegradation whose efficiency is determined by the form of the degraded compound. Numerous studies are underway on the use of advanced oxidation processes (AOPs) to remove phenoxy acids. The efficiency of phenoxy acid degradation using AOPs varies depending on the choice of oxidizing system and the conditions optimizing the oxidation process. Most often, methods combining UV radiation with other reagents are used to oxidize phenoxy acids. It has been found that this solution is more effective compared with the oxidation process carried out using only UV.

The world's non-renewable energy resources continually decline and therefore there is an urgent need to seek and use any available renewable energy sources. An alternative to conventional fuels can be the usage of plant biomass for energy purposes. This particularly relates to plants with C4 photosynthesis, a large increase in biomass, low habitat requirements, and high resistance to diseases and pests. All these characteristics are met, among others, by switchgrass which in many countries occurs as a common wild plant. In agricultural production, switchgrass does not pose many agronomic problems; moreover, it is a very durable plant that can be used in one stand for even 10 years and can be grown in all soils, even contaminated ones. Effective use of switchgrass for bioethanol, biogas or syngas production provides measurable ecological benefits and in the long term offers a chance to maintain a sustainable national energy balance, given the continuously shrinking non-renewable fuel resources. Due to the multifaceted use of this plant and a number of features important from the point of view of the power generation industry, it is worth having a closer look at the possibility of spreading the cultivation of this species.

A b s t r a c t. The degradation rates of three herbicides (alachlor, atrazine, and bentazone) were examined according to OECD Guideline 307 in three profiles of grey-brown podzolic soil (Luvisol) in a laboratory experiment. The aim of the experiment was to determine herbicide degradation parameters and their relationships with soil properties. Degradation processes were effectively described by a first-order model. However, in some cases, the best results were produced by bi-phasic kinetics (hockey-stick and bi-exponential model). The degradation rates of the tested herbicides at 25°C and 40% maximum water holding capacity, established based on half-life values in the Ap horizon, increased in the following order: atrazine (32.6-42.8 days)

Fosforany i azotany(V) w wodach gruntowych jako element zanieczyszczenia środowiska przyrodniczego Phosphates and nitrates(V) in groundwater as an element of natural environment pollution Streszczenie. W pracy przedstawiono wyniki badań zawartości azotanów(V) i fosforanów w wodach drenarskich pochodzących z rolniczych obszarów województwa lubelskiego. Badania wykonano w latach 2008-2010. Próbki wód pobierano ze studzienek lub z piezometrów w dwóch terminach: wiosną i jesienią. Wykazano, że istotne różnice w stężeniu azotanów(V) i fosforanów występowały w wodach pomiędzy niektórymi kategoriami agronomicznymi gleb. W terminie wiosennym najwięcej przypadków o istotnie najwyższym stężeniu azotanów(V) i fosforanów stwierdzono w próbkach wody pobranych z gleb lekkich, natomiast jesienią-w wodach z gleby organicznej (azotany(V)) oraz organicznej i ciężkiej (fosforany). W próbkach pobranych wiosną, niezależnie od roku badań, obserwowano większe stężenia azotanów(V) niż w wodach pobieranych w terminie jesiennym. W przypadku stężeń fosforanów podobny związek stwierdzono w 2008 r. Oznacza to, że następował ubytek azotanów(V) i fosforanów z badanych gleb, a jednym ze sposobów przemieszczania się tych składników poza profil glebowy mogło być ich wymywanie do wód gruntowych. Stwierdzono dodatnią i istotną statystycznie zależność pomiędzy stężeniami azotanów(V) i fosforanów w wodach pobranych wiosną 2008 r.