[Analysis of Pollution Characteristics and Primary, Secondary Contributions of Firework Burnings in Qingdao During the Spring Festival].

Atmospheric pollution frequently occurs in northern China during winter heating period, wherein nitrate became the dominant driver for PM2.5 accumulations. However, sulfate accumulation was found to be significantly higher than that of nitrate during firework burning events and exhibited different pollution characteristics. Online data available from February 2, 2019 to February 10, 2019, including observation data measured from AIM-IC in suburban Qingdao and meteorological data from national automatic monitoring station, were analyzed. The results showed that particulate accumulation, dust and firework burning events were observed. The primary contribution rates of the most intensive firework burning to PM2.5 and PM10 were 69.8% and 63.8%, respectively. In contrast to a severe accumulation of nitrate during the particulate accumulation event, the sulfate formed prior and exhibited more severe accumulation than nitrate during the firework burning events. The primary contribution factors n(SO42-)/n(K+) and n(NO3-)/n(K+) of firework burnings was 1.2 and 1.3 (molar ratios), respectively. The secondary contribution factors were 2.1 and 1.6 times, under relatively stable meteorological conditions. However, during the transit of dry and cold air, the value of secondary contribution factors decreased substantially and exhibited nearly the same values as the primary ones.

[Heavy metal concentrations and pollution assessment of edible crops grown on restored manganese mine lands in Guangxi, South China].

A survey on the crops grown on the restored manganese mine lands in Pingle and Lipu of Guangxi was conducted, and the heavy metal concentrations in the edible parts of the crops were analyzed. The results showed that the heavy metal concentrations in the crops were 1.18-20.46 mg x kg(-1) for Zn, 0.52-16.16 mg x kg(-1) for Pb, 0.33-6.62 mg x kg(-1) for Cr, 0.01-6.24 mg x kg(-1) for Cu, and 0.01-2.76 mg x kg(-1) for Cd. Among the crops, beans had the highest concentrations of almost all test metals, followed by potatoes. The assessment of single factor pollution indices indicated that in the main, the crops were not polluted by Zn and Cu, but heavily polluted by Pb, Cr and Cd, with the pollution rate being 100%, 96.9% and 75.0%, respectively. Comprehensive pollution index indicated that all the crops were polluted by heavy metals, with the heavy, medium and light pollution grade being 87.5%, 9.4% and 3.1%, respectively. Planting edible crops directly on manganese mine wastelands might have great risk for human health, and the existing restoration patterns should be reconsidered.