Elena Pet

A novel exploratory chemometric approach to environmental monitorring by combining block clustering with Partial Least Square (PLS) analysis

BackgroundGiven the serious threats posed to terrestrial ecosystems by industrial contamination, environmental monitoring is a standard procedure used for assessing the current status of an environment or trends in environmental parameters. Measurement of metal concentrations at different trophic levels followed by their statistical analysis using exploratory multivariate methods can provide meaningful information on the status of environmental quality. In this context, the present paper proposes a novel chemometric approach to standard statistical methods by combining the Block clustering with Partial least square (PLS) analysis to investigate the accumulation patterns of metals in anthropized terrestrial ecosystems. The present study focused on copper, zinc, manganese, iron, cobalt, cadmium, nickel, and lead transfer along a soil-plant-snai food chain, and the hepatopancreas of the Roman snail (Helix pomatia) was used as a biological end-point of metal accumulation.ResultsBlock clustering deliniates between the areas exposed to industrial and vehicular contamination. The toxic metals have similar distributions in the nettle leaves and snail hepatopancreas. PLS analysis showed that (1) zinc and copper concentrations at the lower trophic levels are the most important latent factors that contribute to metal accumulation in land snails; (2) cadmium and lead are the main determinants of pollution pattern in areas exposed to industrial contamination; (3) at the sites located near roads lead is the most threatfull metal for terrestrial ecosystems.ConclusionThere were three major benefits by applying block clustering with PLS for processing the obtained data: firstly, it helped in grouping sites depending on the type of contamination. Secondly, it was valuable for identifying the latent factors that contribute the most to metal accumulation in land snails. Finally, it optimized the number and type of data that are best for monitoring the status of metallic contamination in terrestrial ecosystems exposed to different kinds of anthropic polution.

ORGANIZATION OF HUMAN RESOURCES IN RURAL TOURISM UNITS

In the advanced countries, the tertiary sector to which the tourism belongs to has the highest employment degree, the tourism industry being the most powerful labor force absorbent. In Romania, labor force structure shows that 31.3% of the country population is employed in the tertiary sector, from which only 10.6% work in tourism and trade. The rural tourism household must be endowed with the necessary staff to receive tourists and to perform services. Human resources from rural tourism households are either persons belonging to the family, neighbors and acquaintances, either other persons from that locality. In the organization of a tourism pension, we must take into account the work potential structure: number of family members, health condition, structure per age, sex, professional qualification, sources of daily, monthly and annual incomes. Young people play a decisive role in rural tourism development. Although at the beginning they do not have too many material goods, they have power to work, interest, passion, so that their business may prosper. Middle-age families, although they have experience in the organization of a rural tourism pension, their households need modernization and updates in order to meet travelers’ requirements. In the situation when there are human resources belonging to several generations in the rural tourism farms, we consider that the activity may be performed successfully due to the distribution per ages and professions, and the ones involved will have, beside the satisfaction generated by their social utility, the material satisfaction as well. Even if one of the obstacles for rural tourism extension is represented by the lack of qualified labor force, the human resources that perform services in rural tourism units must meet the following conditions: to be able to work, to be able to cook good and diverse food under adequate hygiene-sanitary conditions, to do the cleaning and to combine all qualities to perform the activity in good conditions. No matter what the family composition is, rural tourism brings material and family satisfactions, and also the accomplishment of spiritual aspirations, too, in the household.