Changes in the persistence of two phenylurea herbicides in two Mediterranean soils under irrigation with low- and high-quality water: A laboratory approach.

The disappearance of two phenylurea herbicides, chlorotoluron (CHL) and isoproturon (IPU), in two Mediterranean soils, an agricultural calcareous soil (S5) and an organic forest soil (S2), was assessed under irrigation with high- and low-quality water. Irrigation with wastewater, as opposed to irrigation with high-quality water, increased the degradation rate of both herbicides in both soils. For each soil, the decay rate of IPU was always higher than that of CHL, and both pesticides disappeared more rapidly from S5 with lower clay and organic carbon content than from S2.

Crystal structure of bis-(9H-6-amino-purin-1-ium) hexa-fluorido-silicate(IV) dihydrate.

The asymmetric unit of the title compound, 2C5H6N5 (+)·SiF6 (2-)·2H2O, contains one adeninium cation, half of a hexa-fluorido-silicate anion located on an inversion centre and one lattice water mol-ecule. The adeninium cations are connected through N-H⋯N hydrogen bonds involving one H atom of the -NH2 group and the H atom of the protonated N atom of the adenine ring system, forming centrosymmetric ring motifs of the type R 2 (2)(10) and R 2 (2)(8), respectively. The overall connection of the cation leads to the formation of planar ribbons parallel to (122).

Crystal structure of cis-tetra-aqua-dichlorido-cobalt(II) sulfolane disolvate.

In the title compound, [CoCl2(H2O)4]·2C4H8SO2, the Co(II) cation is located on the twofold rotation axis and is coordinated by four water mol-ecules and two adjacent chloride ligands in a slightly distorted octa-hedral coordination environment. The cisoid angles are in the range 83.27 (5)-99.

Crystal structure of 3-carbamo-thio-yl-pyridinium thio-cyanate.

In the cation of the title salt, C6H7N2S(+)·SCN(-), the C=S bond is oriented trans with respect to the C-C=N fragment in the pyridine ring. The planes of the aromatic ring and the thio-amide fragment of the cation make a dihedral angle of 38.31 (4)°.

Assessment of phenylurea herbicides sorption on various Mediterranean soils affected by irrigation with wastewater.

The retention values of two herbicides, chlorotoluron and isoproturon, in five Mediterranean soils were assessed by two different approaches, a dynamic method, using a batch technique (BT) and a static method, using a soil saturated paste (SP). The SP method led in all cases to lower herbicide sorption when compared with BT, although pesticide distribution constants from both methods were linearly related for the set of used soils (R(2)⩾0.99) showing that both methods similarly reflected the behaviour of the different soils.