Natural Usage of Bottom Sediments on the Base of Existing Law Rules

This paper attempts to assess the quality of sediments derived from surface water, in order to assess their suitability for use as fertilizers or as material for ground reclamation procedures. Bottom sediments contain high amounts of organic matter and this base could be a potential source of easily accessible nutrients and organic matter, which could increase the water capacity of soil and moreover contribute to the stabilization of soil pH. The studied sediments came mostly from small water reservoirs (small lakes and canals) supplied by rainwater. Sample OS 0 (shown as "reference sample") was taken from small reservoir with small forest catchment area. Samples OS I - OS IV were exposed to the impact of: agriculture, rainwater coming from industrial areas, non-ferrous metal smelter and rainwater from city recreational areas. All samples were taken by Eckman-Birge sediment sampler. In the studied samples basic parameters for general characterization (pH, organic matter content, hydration) were defined. The main investigated parameters include heavy metals and organochlorine pesticides content, both of which are required for the analysis according to the polish law, enactment 2002 No. 165 pos.1359. The studied bottom sediments, although originated from different reservoirs, were organic and all belong to gytia sediment type. High amounts of organic matter in all examined samples allowed the comparison of recorded concentrations of heavy metals and pesticides. One of the tested samples was different - sediment OS III. This sample was contaminated with petroleum compounds originating from the maneuver yard from industry plant. Obtained results indicates the high contents of heavy metal in samples exposed to industrial effluents and metal smelter. In this case, such deposits cannot be applied as fertilizers on agricultural soils. The content of pesticides in the studied sediments was high and all tested samples (except 'reference' sample OS 0), showed supranormal quantities. On this basis, the test samples OS I - IV OS are not suitable for the use on natural soils used for agriculture, but the first two investigated sediments (OS I OS II) can be used on soils of industrialized areas. In the group of chlorinated pesticides, in tested samples high concentrations of DDT and g-HCH compounds were recorded. The use of sediments as fertilizers, materials for improving soil parameters, or for ground reclamation is increasing, due to decreasing amounts of good quality organic fertilizers (e.g. manure) and difficulty in saving utilization sediments from dredging water reservoirs. The reported results indicate the real possibility of using bottom sediments as organic fertilizers, especially when they came from small reservoirs or lakes with uncontaminated catchment areas.