Sanitation assessment of wastewater treated by stabilization ponds for potential reuse in agricultural irrigation sanitation assessment

Wastewater reuse has become an important alternative to agricultural irrigation; on the other hand, it poses concern with regard to public health. Total coliform and Escherichia coli concentration, presence of helminth eggs and Salmonella, and physical-chemical parameters were evaluated in raw and treated wastewater. Chemical and biochemical oxygen demand removal efficiency was 74.6 and 77.9%, respectively. As for organic nitrogen, total phosphorus, and total suspended solids, total efficiency removal was 17.4, 12.5, and 32.9%, respectively. The average density of total coliforms and E. coli was 3.5 x 10(9) and 1.8 x 10(8) MPN/100 mL and 1.1 x 10(7) MPN/100 mL and 3.9 x 10(5) MPN/100 mL for raw and treated wastewater, respectively. Ascaris eggs were observed in 80.8% of the samples collected, and viable eggs in 42.3% of the samples. Salmonella was detected in 36.4% of the samples. The values observed in treated wastewater did not show the adequate bacteriological quality, as recommended by World Health Organization (Geneva, Switzerland). Therefore, additional measures should be taken to achieve an improved microbiological and parasitological quality.

Response of black oats (Avena strigosa Schreb) on the aspersion irrigation and nitrogen fertilization

The objective of the study was assessing the effect of the nitrogen and the aspersion irrigation on the growth and dry matter yield of black oats (Avena strigosa Schreb). The experiment was conducted in the Campus of USP in Pirassununga, Sao Paulo State. In the study were evaluated four nitrogen levels (0, 50, 100 and 150 kg of N ha(-1)) and also the presence or absence of the irrigation. The plant variables evaluated were: mean height, dry matter percentage, yield and growth rate. The results had disclosed to greater height of plant in the irrigated condition, reflecting in the higher production of dry matter. In dry land area, percentage of DM was 24.7% and in irrigated area 18.7%. The nitrogen was significantly only for plant mean height that showed linear fit when carried through the irrigation. The effect of the irrigation was better for the production of black oats than nitrogen.

Screening for endophytic nitrogen-fixing bacteria in Brazilian sugar cane varieties used in organic farming and description of Stenotrophomonas pavanii sp. nov.

A Gram-negative, rod-shaped, non-spore-forming and nitrogen-fixing bacterium, designated ICB 89(T), was isolated from stems of a Brazilian sugar cane variety widely used in organic farming. 16S rRNA gene sequence analysis revealed that strain ICB 89(T) belonged to the genus Stenotrophomonas and was most closely related to Stenotrophomonas maltophilia LMG 958(T), Stenotrophomonas rhizophila LMG 22075(T), Stenotrophomonas nitritireducens L2(T), [Pseudomonas] geniculata ATCC 19374(T), [Pseudomonas] hibiscicola ATCC 19867(T) and [Pseudomonas] beteli ATCC 19861(T). DNA-DNA hybridization together with chemotaxonomic data and biochemical characteristics allowed the differentiation of strain ICB 89(T) from its nearest phylogenetic neighbours. Therefore, strain ICB 89(T) represents a novel species, for which the name Stenotrophomonas pavanii sp. nov. is proposed. The type strain is ICB 89(T) (=CBMAI 564(T) =LMG 25348(T)).

Trace-metal biogeochemistry in the Mediterranean Thau Lagoon, a shellfish farming area

The present study contributes to the knowledge of the biogeochemistry of Pb, Cd, Cu, and Ni in the Mediterranean Than Lagoon, southern France, which is an important shellfish farming system. The concentrations of the metals were determined in sediment cores and the overlying waters using inductively coupled plasma mass spectrometry. Particular attention was given to the determination of dissolved Cu species because of their dual role as essential nutrient and toxicant to planktonic organisms. Dissolved Cu speciation was determined using the diffusive gradient in thin-film technique (DGT) and competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV). Our data indicated a significant historical contamination of the sediments, which commenced in the second half of the 19th century, with trace metal inputs persisting until the end of the 20th century. In recent years a decrease in metal contamination has become apparent. The maxima observed for Pb, Cd, and Cu profiles probably indicate the occurence of anoxia crises. A strong complexation of the dissolved Cu species was observed in the waters of the Than Lagoon, which reduced the bioavailability of Cu. The dissolved Cu(2+) concentrations were probably too low to cause direct toxic effects on shellfish, but the highest concentration (5.29 pM) observed in this study can potentially influence phytoplankton communities. A comparison between the Cu speciation data indicates that up to 50% of the complexed Cu determined using CLE-ACSV was DGT labile.