| The reform and opening up has greatly improved our living standards.Consequently,the demands for meat by the people has increased dramatically.Pork is an important part of our national diet.With the continuous expansion of pig farms,the environmental pollution associated with swine production has become a fundamental issue which limits the sustainable development of the pig industry.This study was conducted to characterize the pollution of suspended particulates in nursery pig houses of two pig farms in Jiangxia District of Wuhan City.From January 2017 to January 2018,PM2.5 and PM10 samples were collected and analyzed during three campaigns.Water soluble inorganic ions(Na+,NH4+,K+,Mg2+,Ca2+,Cl-,NO3-,PO43-and SO42-),heavy metal elements（Fe,Zn,Cu,Mn,Ni,As,Pb,Cd,Cr,Co and V）and organic carbon（OC）,elemental carbon（EC）concentrations were determined.The results obtained are as follows:1.The PM concentrations in the nursery pig houses were relatively high during the sampling period.The daytime and nighttime average mass concentrations of PM2.5 in nursery pig house A were 521.3±142.9μg/m3 and 425.5±192.6μg/m3,respectively.The corresponding concentrations of PM10 were 2574.5±556.3μg/m3 and 1769.8±207.0μg/m3.As for nursery pig house B,indoor PM2.5 was 140.6±85.2μg/m3 and outdoor PM2.5 was111.2±49.4μg/m3,while indoor PM10 reached 506.4±360.4μg/m3.In pig house B,the ratio of PM2.5 to PM10 in the pig house B were 0.45±0.08 and 0.26±0.04 in summer and winter,respectively,which are much less than those observed in the ambient atmosphere.The particles in the pig house may be mechanically generated from the sources within the pig house.2.In general,water soluble inorganic ions are the main components of suspended particulates in pig houses.Among them,NO3-and Ca2+took the large share.In addition,concentration of PO43-in PM was relatively high in comparison to the value in the outdoor air.The ion balance calculation found that the particles in both farms were alkaline.3.Among the analyzed heavy metal elements,the proportion of Fe in the suspended particles in the two pig houses was the largest.In pig house A,the total concentration of heavy metals in PM2.5 was higher during the day than that at night,and PM10 was higher during the night than in the daytime.In pig house B,except for Fe,Cu and V,the indoor element concentrations were higher than those outdoor.By measuring the heavy metal content in the feed of pig house B,we found that the heavy metal content of suspended particulate matter in the pig farm environment was affected by the heavy metal content of feed,such as Fe,Pb,Zn and Cu.4.In both pig houses,the OC values were significantly higher than the EC values,and the organic components were predominant in the particles.In addition,SOC content was high.5.Although there were differences in the farming scale and breeding methods between A and B,some common features were found in terms of PM pollution charateristics:The concentration of particles in the farm was generally high;water soluble inorganic ions,total organic carbon and heavy metal elements were the important components of the particles;The concentration of NO3-,Ca2+,PO43-,and the ration of OC/EC were generally higher than those in the outdoor air.This may be partially explained by the fact that feed and feces contribute to the PM pollution in the pig house. |
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