River bottom sediment from the Vistula as matrix of candidate for a new reference material

Utilization of PCB-contaminated Hudson River sediment by thermal processing and phytoremediation

The need to dispose of dredged sediments and development of appropriate technology for their safe utilization has become a growing problem in recent years. It has been proposed that dredged, fresh sediments can be utilized in agriculture or environment; however there is also growing interest in the use of thermally-treated sediments. Hence, the aim of this study was threefold: 1) to evaluate the effect of two incineration temperatures (300 °C and 600 °C) on the chemical and ecotoxicological properties of sediment; 2) select the appropriate treatment for further phytoremediation experiments with zucchini; and 3) assess the impact of sediment admixture on the physico-chemical parameters of soil, based on the responses of Aliivibrio fischeri and growth of zucchini (Cucurbita pepo L. cv 'Black Beauty'). A range of chemical (inductively-coupled plasma optical emission spectrophotometry for macro- and trace elements; gas chromatography for polychlorinated biphenyls (PCBs)), ecotoxicological (Microtox assay), and plant morphology (biomass measurement) as well as physiological analyses (spectrophotometry for chlorophyll) were applied. River sediments incinerated at 600 °C resulted in better chemical and ecotoxicological properties than incinerated at 300 °C or no incinerated. Incineration at 600 °C removed PCBs from sediment. In culture experiments conducted with zucchini, sediment treated at 300 °C demonstrated a 51-81% reduction in PCB concentrations compared to untreated sediment. After four weeks of growth, the raw sediment showed a significant increase in K, Fe, Cr, Pb, Zn concentrations, whereas the thermally-processed sediment showed a decrease in Ca, Na, P, Cd, Cu, Ni, and Zn concentrations. Both the fresh and thermally-treated sediment types influenced plant growth positively: they demonstrated higher biomass production than plants grown in control soil; however, plants grown on soil with thermally-processed sediment demonstrated lower biomass than those grown in raw sediment. Chlorophyll content was affected negatively by admixtures of soil with treated or untreated sediment, while a lower chlorophyll a/b ratio was observed in plants grown on an admixture of thermally-treated sediment with soil. Our findings suggest that the use of sediments as a growth medium component may be a promising way for their utilization and transformation from waste material to a valuable resource enhancing the benefits to the environment.

Effects of amendments of PCB-containing Hudson River sediment on soil quality and biochemical and growth response of cucumber (Cucumis sativus L. cv 'Wisconsin SMR 58')

Approximately 200 million m³ of sediments are dredged every year in the United States. Of this amount, 2.3-9 million m³ are contaminated to the extent that they require special, and often costly, handling. Therefore, there is a pressing need to develop appropriate technology for the safe utilization of these sediments, especially in the case of the Hudson River, which is well known to demonstrate significant polychlorinated biphenyls (PCBs) contamination. Hence, the aim of the present study was to examine the influence of different doses of Hudson River sediments (10%, 25%, 50%, 75% and 100% admixtures) on soil quality and on the biochemical and growth response of cucumber (Cucumis sativus L. cv 'Wisconsin SMR 58'), used as potential phytoremediation tool for sediment-borne PCBs. A sediment/soil admixture was found to significantly decrease the nitrogen (N) content in the substratum; in addition, phosphorus (P) content was significantly increased by 50-100% sediment, while potassium (K) content was significantly increased by 10% sediment, and significantly decreased by >50% sediment. Although sediment treatment resulted in a gradual increase in PCB content in the soil-sediment substratum, exceeding the threshold effect concentration (TEC) for the ≥50% sediment admixture, the Microtox assay did not suggest toxicity to microorganisms. The results demonstrated also that admixture of 10-25% Hudson River sediment increased cucumber growth; however, higher doses led to growth inhibition, manifested as lower biomass and smaller leaves. Also, chlorophyll a and b content decreased with increasing doses of sediment. Phenylpropanoid and flavonol contents were significantly higher in plants grown in soil amended with 10% of sediment, but significantly lower in soil treated with a 100% sediment admixture. The anthocyanin content in plants was lower at admixtures of 50% and higher. The obtained results corresponded with the decreasing content of N and K.

Evaluation of ecotoxicological and chemical properties of soil amended with Hudson River (New York, USA) sediment

The aim of this study was to assess the potential for application of Hudson River sediment as a plant growth medium by mixing with various proportions of soil. The growth medium obtained by the admixture of soil and Hudson River sediment was characterized by optimal pH, reduced salinity, and presence of macro- (K, Mg) and micronutrients (Fe, Mn). Apart from beneficial nutrients and organic matter, the riverine sediment also contained toxic metals (Zn 86 mg; Cu 17.8 mg; Ni 16.6 mg; Cr 20.7 mg; Cd 0.46 mg; Pb 20.7 mg/kg, at concentrations below the threshold effect concentration) and PCBs (total concentration 254 ng/g), which can have a negative impact on soil ecosystems. The results ecological risk assessment of six trace elements and PCBs in sediment suggested medium/moderate risk (PECq = 0.21) and the need for ecotoxicological tests prior to its use as a growth medium. However, ecotoxicity tests of the soil/sediment admixture indicated that it was non-toxic or less-toxic to crustacean Heterocypris incongruens (PE = - 8-38%) and bacteria Aliivibrio fischeri (PE = - 20-38). For Sinapis alba L. and Lepidium sativum L., the germination index (GI) indicated the dominance of inhibitory effect on plant growth; whereas for the Sorghum saccharatum L., the GI value showed the stimulatory effect. Based on the above physicochemical and ecotoxicological analyses, the sediment was found suitable for use as a growth medium, for non-edible plants. It is worth to underline that this sediment was collected from relatively less contaminated location of the river and therefore the results may not represent sediments from entire stretch of the Hudson River.