Arsenic, cadmium, and lead pollution and uptake by rice (Oryza sativa L.) grown in greenhouse

Purpose: Hunan province is well-known for its extensive base-metal extraction and smelting industries. However, the legacies of excavation operations, transportation, and selective smelting activities within Hunan have resulted in the generation of large quantities of mine wastes, which will become the sources of metal contamination in the environment. Thus, there is an increasingly important health issue underlying the study of arable land pollution and transfer of As, Cd, and Pb in the paddy soil–rice system.
Materials and methods: Paddy soils collected from mining- and smelting-impacted areas in Hunan province and rice seed (Oryza sativa L. cv Jia Hua-1) were used for pot experiments under greenhouse conditions. One 30-day-old seedling was transplanted into one pot containing 5.0 kg pretreated soil. At harvest, rice grains and shoots were washed with distilled water to remove surface soil, and oven-dried at 65°C for 96 h until a constant weight was reached. Roots were washed carefully with distilled water for the next process of extracting iron plaque using dithionite–citrate–bicarbonate solution. Total concentrations of As, Cd, and Pb in soil and rice plant tissues were measured by inductively coupled plasma mass spectrometer.
Results and discussion: Total concentrations of As, Cd, and Pb in the soils collected from 12 mining- and smelting-impacted areas in Hunan province were much higher than Hunan background values and exceeded the maximum concentration limit for soils set by the Ministry of Environmental Protection. The yields of rice grain from Pb/Zn mining and smelting sites were negatively correlated to overall pollution scores. Distributions of As, Cd, and Pb in rice plant followed: root >> shoot > husk > whole grain. About 30.1–88.1% of As, 11.2–43.5% of Cd, and 14.0–33.9% of Pb were accumulated in iron plaque on root surfaces.
Conclusions: High concentrations of As, Cd, and Pb are observed in paddy soils from mining- and smelting-impacted areas in Hunan province, indicating those paddy soils suffer serious combined heavy metal contamination. In particular, Cd is the dominant contaminant followed by As and Pb in paddy soils from most locations. The distributions of As, Cd, and Pb in rice tissue were: root >> shoot > husk > whole grain. Concentrations of Pb in all whole grain and of As and Cd in 50% of whole grain samples exceeded Chinese Hygienic Standard values for food.

Impact of weather conditions on electric vehicle performance

Seasonal and day-to-day variations in travel behaviour and performance of private passenger vehicles can be partially explained by changes in weather conditions. Likewise, in the electricity sector, weather affects energy demand. The impact of weather conditions on private passenger vehicle performance, usership statistics and travel behaviour has been studied for conventional, internal combustion engine, vehicles. Similarly, weather-driven variability in electricity demand and generation has been investigated widely. The aim of these analyses in both sectors is to improve energy efficiency, reduce consumption in peak hours and reduce greenhouse gas emissions. However, the potential effects of seasonal weather variations on electric vehicle usage have not yet been investigated. In Ireland the government has set a target requiring 10% of all vehicles in the transport fleet to be powered by electricity by 2020 to meet part of its European Union obligations to reduce greenhouse gas emissions and increase energy efficiency. This paper fills this knowledge gap by compiling some of the published information available for internal combustion engine vehicles and applying the lessons learned and results to electric vehicles with an analysis of historical weather data in Ireland and electricity market data in a number of what-if scenarios. Areas particularly impacted by weather conditions are battery performance, energy consumption and choice of transportation mode by private individuals.