[Response of cotton seeding date to climate warming in Northern Slope Economic Zone of Tianshan Mountain, China].

Based on the meteorological date acquired from 11 meteorological stations in Northern Slope Economic Zone of Tianshan Mountain during 1971-2010 and by using the methods of linear regression, t-test technique and IDW interpolation, this paper analyzed the spatial distribution of each ten-day average temperature from late March to late April and beginning date of ≥ 12 °C to understand the effect of climate change on the cotton seeding date. Results showed that each ten-day average temperature from late March to late April increased by 0. 8, 0. 5, 0. 1 and 0. 5 °C . (10 a)-1, but the beginning date of ≥12 °C advanced by 0.5 d . (10 a)-1 during 1971-2010. All meteorological elements in this research ascended abruptly in the 1990s. The abrupt climate change made each ten-day average temperature increasing by 2.5, 1.9, 1.1 and 1.5 °C, to 7.2, 10.0, 13.2 and 15.6 °C, respectively from late March to late April. The high values of each ten-day average temperature from late March to late April expanded the scope of main cotton producing areas in Northern Slope Economic Zone of Tianshan Mountain, such as Wusu, Sawan and Manasi, and the low values were observed in Urmuqi. The spatial distribution of the beginning day of ≥12 °C was significant different in different regions. During this study period, the early beginning dates of ≥ 12 °C expanded the scope of Jinghe and Manasi as cotton producing areas, and the late beginning dates of ≥ 12 °C narrowed to areas around Urumqi. With the advance of the beginning day of ≥ 12 °C, the seeding date of cotton could start from 22nd to 28th April in most of the counties, and mulch cover could bring forward the suitable sowing date to 15th through 21st April.

Accumulation and risk assessment of heavy metals in water, sediments, and aquatic organisms in rural rivers in the Taihu Lake region, China.

Concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) were measured in water, sediments, Ceratophyllum (hornwort), and Bellamya sp. (edible snail) from residential, mixed (industrial and commercial), and agricultural areas with rural rivers in the Taihu Lake region, China. Zn concentrations were the highest, whereas Cd concentrations were the lowest among the six metals in water, sediments, and aquatic organisms. Cd was mainly present in the acid-soluble fraction, Cr in the residual fraction, and Pb in the reducible fraction of sediments. Heavy metal concentrations in water, sediments, and aquatic organisms in the three areas followed the order of the mixed area > residential area > agricultural area. Heavy metal concentrations in aquatic organisms were not only related to total metal concentrations in water and sediments but also to metal speciation concentrations in sediments. In addition, the bio-concentration factor (BCF) values of Cr, Cu, Pb, and Zn for Bellamya sp. were higher than those for Ceratophyllum, whereas the BCF values of Cd and Ni for Bellamya sp. were lower than those for Ceratophyllum. An ecological risk assessment of heavy metals in sediments showed that Cd posed the highest ecological risk to the environment. A health risk assessment showed that consuming Bellamya sp. from the mixed area could cause a potential health risk.