Global NEST Journal

The structure and function of communities and biological systems favorable and unfavorable to salt
production in the ponds of solar saltworks are described. Favorable systems maintain a diverse biota
and power the organisms at levels that enable a saltworks to economically and continuously produce
high quality salt at design capacity. Unfavorable systems-the result of disturbances and high concentrations
of nutrients in the water-are dominated by a few species that release massive quantities of
organic substances, decrease pond surface areas and volumes, and decrease salt quality and quantity.
Management practices to obtain and maintain favorable systems under a variety of conditions are
reviewed.

Soil-contamination from toxic explosive residues at military bases throughout the world, is a major
environmental concern. A strong candidate for TNT soil-contamination within Greece, is the military
base/airport of Maleme in Crete. While soil sampling was in progress new routes of trace analysis for
explosives in soil were explored. Solid-phase micro-extraction (SPME) was used to selectively preconcentrate
analytes prior to GC/MS. In the preliminary experiments (effectuated on water-spiked samples)
optimization of the SPME technique was achieved by controlling parameters such as sampling
method, salt content and sample agitation. As immersion of the SPME fiber was found to be more efficient
for extracting most analytes of interest, a pretreatment step was introduced for the soil samples
which simply converted them to water samples. The developed SPME protocol was able to screen
explosives in spiked-soils, in concentrations well below the certified reporting and detection limits.

Adsorption and removal of commercial dyes were studied in aqueous suspensions of fly ash mixtures
with a sandy clay loam soil of low organic matter content. The commercial dyes, acid orange 7, acid yellow
23, disperse blue 79, basic yellow 28 and direct yellow 28 represent the widely used nitroazo structures.
Batch and column experiments were carried out at equilibrium conditions for concentrations of
dyes between 5 and 60 mg l-1. The logarithmic form of Freundlich equation gave a high linearity and
the k constants are increasing with the increase of fly ash content in adsorbent mixtures and the affinity
between the adsorbent surface and adsorbed solute. The mean removed amounts of dyes by adsorption
batch experiments in soil mixture with 20% fly ash content were up to 53.0% for acid yellow 7,
44.9% for acid yellow 23, 99.2% for direct yellow 28, 96.8% for basic yellow 28 and 88.5% for disperse
blue 79. The removal of dyes from column experiments decrease with the increase of the solution concentration
form 10 to 50 mg l-1 at 20 °C, showing the process to be highly dependent on the concentration
of the solution. The mean removed amounts of dyes by adsorption on columns of soil mixture
with 20% fly ash content and for initial concentration of dye solutions 50 mg l-1 were up to 33.8% for
acid yellow 7, 59.4% for acid yellow 23, 84.2% for direct yellow 28, 98.2% for basic yellow 28 and 60.3%
for disperse blue 79.