15 research outputs found
The microbiotest battery as an important component in the assessment of snowmelt toxicity in urban watercourses—preliminary studies
The aim of the study was to use a battery of
biotests composed of producers (Selenastrum
capricornutum, Sorghum saccharatum, Lepidium
sativum, and Sinapis alba), consumers (Thamnocephalus
platyurus), and decomposers (Tetrahymena thermophila)
to evaluate the toxicity of snowmelt and winter storm
water samples. The toxicity of the samples collected in
the winter period December to February (2010–2011), in
one of the largest agglomerations in Poland, the city of
Lodz, was compared to that of storm water samples taken
under similar conditions in June. The most toxic snowmelt
samples were found to be high acute hazard (class IV),
while the remaining samples were rated as slight acute
hazard (class II). L. sativum (in the Phytotox test) was the
most sensitive test organism, giving 27 % of all toxic
responses, followed by S. capricornutum with 23 % of
all responses. T. thermophila was the least sensitive, with
only 2 % of all toxic responses. The greatest range of
toxicity was demonstrated by samples from the single
family house catchment: no acute hazard (class I) to high
acute hazard (class IV
Selenium in the environment
Selenium is an element that is of interest to many researchers. As a trace element, it occurs in
all compartments of the natural environment. It can be found both in an organic and inorganic
form in water, rocks and air. For a long time, this element had been identified as a hazardous
substance due to its toxicity. It was only in recent years that the physiological need to use it as
a micronutrient fundamental to the health of humans and animals was noticed. However, it is
not necessary for the growth of plants. In appropriate doses, selenium significantly affects the
health of humans and animals because it is a component of many enzymes and it has antioxidative
and anticancerogenic activity, but in excessive amounts it exhibits a toxic effect and causes
a disease called selenosis. Its deficiency, however, is a much greater problem. It may occur in
people living in most areas of the world. Selenium is an exogenous element, which is supplied to
the human organism with food. Because plants are the main source of this element, it is important
to increase its plant level. This can be achieved in different ways. One of the most promising
approaches in addressing the problem of a low level of Se transfer from soil to the food
chain is the agronomic biofortification of Se. Other interesting solutions are genetic engineering
and the use of naturally selenium-rich materials. A new approach to fertilization of plants with
Se is the use of nanomaterials. However, an excess of this element can induce toxic effects, such
as the growth inhibition, wilting and drying of leaves, reduced protein synthesis and death of
immature plants