ABSTRACT
To explore the impact of heavy metals in pollutant emissions from a coal-fired power plant on the soil environment of surrounding farmland, 31 farmland soil sampling sites were set up with the chimney of the power plant as the center using the radiation ring method. The contents of 10 heavy metals in the soil were determined using inductively coupled plasma mass spectrometry(ICP-MS). The characteristics and potential ecological risks of heavy metals in the soil were analyzed. The spatial differentiation and pollution characteristics of heavy metals were investigated based on geostatistical spatial interpolation and an AERMOD diffusion model, and the source analysis of heavy metals was conducted using a PMF receptor model. The results showed that:â the mean contents of the heavy metals ω(Pb), ω(Mn), ω(Zn), ω(Cr), ω(Ni), ω(Cu), ω(As), ω(Co), ω(Hg), and ω(Cd) in farmland around coal-fired power plants were 414.46, 286.38, 155.22, 69.54, 55.77, 53.48, 31.73, 19.86, 0.78, and 0.71 mg·kg-1, respectively. The contents of Hg, Pb, Cd, As, Zn, and Cu all exceeded the background values of Shaanxi Province by 26, 19.36, 7.88, 2.83, 2.23, 2.49, 1.87, 1.11, and 1.93 times, respectively. â¡ The mean value of the potential ecological risk index(RI) of heavy metals in the soil around the coal-fired power plant was 714.53, indicating a strong ecological risk level, and there were high-value rich areas near the Qianhe railway station and the oil and gas company. The single potential ecological risk index(Ei) of the Hg element was 520.92, which was at a very strong ecological risk level. ⢠The main sources of heavy metals in the soil around the coal-fired power plant were dust removal sources from coal burning(32.16%), industrial and agricultural activities(19.78%), natural sources(26.25%), and traffic sources(21.81%). The high heavy metal content in the soil was distributed in the range of 1-2 km from the power plant, whereas the heavy metal content was low in the range of 1 km from the power plant, increasing gradually in the range of 1-2 km and then decreasing gradually when it was greater than 2 km. The spatial differentiation and enrichment characteristics of heavy metals in farmland around the power plant obtained in this study can provide theoretical and data support for soil pollution control.
ABSTRACT
OBJECTIVE: To investigate the mRNA expressions of RASSF1A, Galectin-3 and TPO in papillary thyroid carcinoma and some other thyroid benign lesions, and evaluate their diagnostic significance. METHODS: Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of RASSF1A, galectin-3 and TPO in the samples from 73 cases, including 23 cases with papillary thyroid cancer, 16 with nodular goiter, 29 with thyroid adenoma and 5 with Hashimoto's disease. RESULTS: A statistically significant difference in the mRNA expression of RASSF1A, Galectin-3 and TPO was observed between papillary thyroid carcinoma and follicular benign lesions (P<0.05). However, there was no significant difference among various kinds of benign lesions (P>0.05). A negative correlation of the expression of RASSF1A and Galectin-3 mRNA was found between thyroid benign lesions and malignant ones (P = 0.000). While the mRNA expression of RASSF1A and TPO was positively correlated between benign and malignant lesions (P = 0.028). CONCLUSION: Loss of expression of RASSF1A and TPO mRNA but high expression of Galectin-3 mRNA in papillary thyroid carcinoma are common. Therefore, the products of these three genes may be closely related to the development of thyroid papillary carcinoma, and may be used as useful markers in differential diagnosis of papillary thyroid carcinoma from the benign lesions. The results are more reliable if this detection method is used in combination with other techniques.
