Sources of pesticides in surface waters in Switzerland: pesticide load through waste water treatment plants--current situation and reduction potential

Concentrations of pesticides in Swiss rivers and lakes frequently exceed the Swiss quality goal of 0.1 microg/l for surface waters. In this study, concentrations of various pesticides (e.g., atrazine, diuron, mecoprop) were continuously measured in the effluents of waste water treatment plants and in two rivers during a period of four months. These measurements revealed that in the catchment of Lake Greifensee, farmers who did not perfectly comply with 'good agricultural practice' caused at least 14% of the measured agricultural herbicide load into surface waters. Pesticides, used for additional purposes in urban areas (i.e. protection of materials, conservation, etc.), entered surface waters up to 75% through waste water treatment plants.     

Rieselfelder

Soils of the large sewage farm area south of Berlin are contaminated with heavy metals such as Cd, Cr, Cu, Hg, Ni, Pb, Zn. Based on earlier studies the total amount and the bioavailable proportions of heavy metals in soil samples were analysed. In some samples very high levels of total heavy metal concentrations were detected. For Pb, Cd, Cu and Hg the maximum values were 1360, 29.7, 817 and 40.8 mg/kg soil dry matter, respectively. The biovailable fractions of heavy metals which were found primarily in the acetate and EDTA fractions and to a lesser degree in the water extract account for about 50 % (Pb, Ni), 70 % (Cd) or 90% (Zn) of their total amount and may therefore pose a considerable environmental risk.     

Contaminant levels in colonial waterbirds from Green Bay and Lake Michigan, 1975–80

Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated styrenes (PCSs), and mercury were measured in the eggs of 10 species of colonial waterbirds nesting in areas around Green Bay or Lake Michigan from 1975 to 1980. Residues also were measured in the carcasses and brains of black-crowned night-herons (Nycticorax nycticorax). The highest residues were of PCBs, DDE, mercury, and dieldrin; for some species, levels of these chemicals possibly were high enough to have caused reproductive effects. Other organochlorine pesticides were found at low levels. Only trace amounts of PCSs and PBBs were found. Eggs of herring gulls (Larus argentatus) collected in 1977 from an island in Lake Michigan contained an average of 100 ppm PCBs and 33 ppm DDE; this was the most-contaminated species. Cattle egrets (Bubulcus ibis), the only bird that is not a fish eater, contained only small quantities of DDE and mercury.     

Effect of corona discharge on the gas composition of the sample flow in a Gas Particle Partitioner

A Gas Particle Partitioner (GPP) that allows highly efficient separation of gas and particles with no effect on the thermodynamic conditions and substantially no change of the gas composition has been developed. The GPP is a coaxial arrangement with inner and outer electrodes and utilizes a corona discharge to electrically charge the particles and a strong electric field to remove them from the sample flow. Several measures were taken to avoid an influence of the corona discharge on the gas composition. The GPP can be applied for various applications. This paper focuses on the use of the GPP as a pre-filter for gas analyzers, where zero pressure drop and a minimization of the influence of the corona discharge on the gas composition are the main objective. Due to its design, the GPP introduces no changes to the thermodynamic conditions. However, corona discharge is known to produce significant amounts of ozone and oxides of nitrogen. The effect of the corona on the gas composition of the sample flow was determined under various conditions. The gas concentrations strongly depended on several aspects, such as material and diameter of the corona wire and polarity of the corona voltage. Due to the measures taken to minimize an effect on the gas composition, the concentrations of these gases could effectively be reduced. Along with the maximum gas-particle separation efficiency of near 100%, the additional O3 concentration was 42 ppbV and the additional NO2 concentration 15 ppbV. If an efficiency of 95% is acceptable, the added concentrations can be as low as 2.5 ppbV (O3) and 0.5 ppbV (NO2), respectively.     

The riddle of “life,” a biologist’s critical view

To approach the question of what life is, we first have to state that life exists exclusively as the "being-alive" of discrete spatio-temporal entities. The simplest "unit" that can legitimately be considered to be alive is an intact prokaryotic cell as a whole. In this review, I discuss critically various aspects of the nature and singularity of living beings from the biologist's point of view. In spite of the enormous richness of forms and performances in the biotic realm, there is a considerable uniformity in the chemical "machinery of life," which powers all organisms. Life represents a dynamic state; it is performance of a system of singular kind: "life-as-action" approach. All "life-as-things" hypotheses are wrong from the beginning. Life is conditioned by certain substances but not defined by them. Living systems are endowed with a power to maintain their inherent functional order (organization) permanently against disruptive influences. The term organization inherently involves the aspect of functionality, the teleonomic, purposeful cooperation of structural and functional elements. Structures in turn require information for their specification, and information presupposes a source. This source is constituted in living systems by the nucleic acids. Organisms are unique in having a capacity to use, maintain, and replicate internal information, which yields the basis for their specific organization in its perpetuation. The existence of a genome is a necessary condition for life and one of the absolute differences between living and non-living matter. Organization includes both what makes life possible and what is determined by it. It is not something "implanted" into the living beings but has its origin and capacity for maintenance within the system itself. It is the essence of life. The property of being alive we can consider as an emergent property of cells that corresponds to a certain level of self-maintained complex order or organization.     

Measurement of Opacity and Particulate Emissions with an On-Stack Transmissometer

An on-stack transmissometer system which is designed to provide a precision measurement of the opacity of visible emissions is described. The sources of error in opacity measurements with regard to recent EPA emission monitoring requirements and planned specifications are discussed. Sources of error are voltage changes, temperature changes, light source and detector aging and effects of ambient light. Other major operational errors are caused by alignment drift and soiling drift. The methods employed to minimize these errors achieve an accuracy of ±3% of span and a maintenance free operational period of 3 months. The relationships between optical density, opacity and transmittance are described. The instrument measurement can be correlated with dust loading provided the particle size distribution is constant. Examples are given of correlations obtained between optical density and particulate concentration in the gas on various types of emission sources and the observed error margins are summarized.