Investigation Of Heavy Metal Pollution In Soil-Vegetable System Of Qinghuangdao, China

In recent years, heavy metal pollution incidents happened frequently in our country,which induce food pollution and a serious threat to human health. In order to strengthen theprevention and control of heavy metal pollution,《The comprehensive prevention and controlof heavy metal pollution of the Twelfth Five Year Plan》chaired by the Ministry ofEnvironmental Protection approved by the State Council, becoming the first " Twelfth FiveYear " national plan. In this paper, the sources of heavy metal contamination in soil andcharacteristics were summarized. Soil samples and vegetable samples in the urban area and4countries of Qinghuangdao were collected. Total heavy metal content and available contentwere determined. Both soil and vegetable contamination extent were assessed. The mainresules were as follows:1) The monitoring results of Qinhuangdao heavy metals in soil showed that soilenvironmental quality level in Beidaihe was clean, while which for Haigang district,economic development zone, Changli County, Lulong County and Qinglong County weretolerableness clean and Shanhaiguan and Funing County were beyond the national soilquality standard. Different places had different heavy metal problem. Haigang district,Qinglong County presented cadmium, copper, nickel pollution, while Shanhaiguan, LulongCounty presented cadmium, nickel pollution, economic development zone presentedcadmium, copper pollution, Funing County, Changli County presented copper, nickelpollution.2) Lead, chromium and zinc are100%meeting the national soil quality standards inQinhuangdao vegetable soil, while cadmium, copper and nickel in some palces beyond thestandard. For vegetable soil in Qinhuangdao downtown area, the rate of beyond the standardlevel were21.4%,14.3%,14.3%for cadmium, copper and nickel, respectively. Heavy metalpollution in vegetable land was ranked in Cd>Ni>Cu. For vegetable soil in four counties ofQinhuangdao, the rate of beyond the standard were12.5%,8.3%,20.8%for cadmium, copperand nickel, respectively. Heavy metal pollution of vegetable soil as follows: Ni>Cd>Cu.Comprehensive analysis showed that heavy metals pollution status in Qinhuangdao vegetablesoil is: Ni> Cd>Cu. 3) The correlation between available contents of cadmium, lead, copper, zinc, nickel andfull amount in vegetable soil reach extremely significant level, respectively. The correlationcoefficient for Cu was biggest, followed by Cd, while that for Cr was not significant.4) The contents of cadmium, lead, chromium in cole, cabbage, celery, carrot, potato,cowpea were adopted to meet the standard(GB2762—2012). The single pollution index wasless than0.7, and the comprehensive pollution index was less than0.7, which indicated thatvegetable quality level in this areawas cleanliness. The order of comprehensive pollutionindex for different vegetables were as the order asas carrot> cabbage> cole> celery inQinhuangdao downtown area.The order of comprehensive pollution index in four counties ofQinhuangdao ranked as carrot> cowpea> cabbage> potato> cole> celery. Comprehensivepollution degree of cadmium, lead, chromium in Qinhuangdao vegetables, followed byvegetables, roots and tubers> leafy vegetables> stem vegetables.5) The significant correlations was observed between total cadmium, lead content in cole,cabbage, celery, carrot and soil available cadmium, lead content. A significant correlationwas also found between the content of cadmium in cole, celery and soil available cadmiumcontent, the content of lead in cole, cabbage, celery and available lead content in soil.Inaddation, The correlation between the content of chromium in cole, cabbage and the soil totalchromium content reached significant level. However, no significantcorrelation was foundbetween the content of chromium in celery, carrot and the total chromium content in soil.