Risk assessment and ranking of pesticide residues in Chinese pears

The presence of pesticide residues in pears is a serious health concern. This study presents the results from a 2-year investigation （2013-2014） that used gas chromatography, GS/MS and UPLC/MS-MS to measure the levels of 104 pesti- cides in 310 pear samples. In 93.2% of the samples, 43 pesticides were detected, of which the maximum residue levels （MRLs） were exceeded in 2.6% of the samples. Multiple residues （two to eight compounds） were present in 69.7% of the samples; one sample contained nine pesticides and one sample contained 10. Only 6.8% of the samples did not contain residues. To assess the health risks, the pesticide residue data have been combined with daily pear consumption data for children and adult populations. A deterministic model was used to assess the chronic and acute exposures based on the Joint Meeting on Pesticide Residues （JMPR） method. A potential acute risk was demonstrated for children in the case of bifenthrin, which was found to be present at 105.36% of the acute reference dose （ARfD） value. The long- term exposure of the Chinese consumer to pesticide residues through the consumption of raw pears was far below the acceptable daily intake （ADI） criterion. Additionally, the matrix ranking scheme was used to classify risk subgroups of pesticides and pear samples. In general, 95.5% of samples were deemed to be safe and nine pesticides were classified as being of a relatively high risk. The findings indicated that the occurrence of pesticide residues in pears should not be considered a serious public health problem. Nevertheless, a more detailed study is required for vulnerable consumer groups, especially children. Continuous monitoring of pesticides in pears and tighter regulation of pesticide residue standards are recommended.

Mini-review of application of IoT technology in monitoring agricultural products quality and safety

Internet of Things(IoT)technology has been identified as one of the emerging technologies in information technology(IT),which is widely used in all walks of life in the world.The key technologies of IoT technology,such as radio frequency identification(RFID),wireless sensor network(WSN),sensors and global positioning system(GPS),had been widely used in farmland and greenhouse management,environmental monitoring,cold chain monitoring and tracking,and traceability,etc.As advancements in science and technology,IoT technology has been widely applied in agricultural products quality and safety,which brought a number of potential benefits for detecting agricultural products easier and automatically,improving the efficiency and speed of operations,decreasing the labor cost,promoting the agricultural products quality and safety.This paper intended to introduce the concept of IoT technology,the key technologies used at present and review the recent applications of IoT technology in monitoring agricultural products quality and safety in the whole industry chain,such as production,processing,circulation,sales and traceability.Challenges and trends of agricultural products quality and safety in the future were also discussed.

Suitability evaluation of remediation technology for polluted farmland

The suitability evaluation model of the remediation technology of polluted farmland has been constructed by analytic hierarchy process.The evaluation index of remediation technology has been constructed based on the physical and chemical index of farmland,farming system and the characteristic of remediation technology.In addition,the potential risk factors such as the distance of the industrial and mining enterprises,and the economy factors such as repair cost and local economy level have all been considered to construct the suitability evaluation system of the remediation technology of polluted farmland.Shilou town in Beijing was selected for the testing site,with the pollution of cadmium,arsenic and organic matter pollution.Chemical passivation,phytoremediation and biological compost technology were used for restoring the polluted farmland.According to the suitability evaluation model,the phytoremediation technology is suitable for general pollution.And chemical passivation and biological compost technology are more suitable to restore the polluted farmland.The combined remediation technologies of chemical passivation and phytoremediation are more suitable.It can avoid the limit of the one technology,complement the defect for each other and receive more remediation effects.

UPLC-QTOF-MS Analysis on Isoflavones in Douchi

Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.

Occurrence and distribution of micro-and mesoplastics in the high-latitude nature reserve,northern China

Microplastics pollution has received growing attention worldwide in recent years.However,data on microplastics in the freshwater environment are still limited,especially in high-latitude nature reserves in Northern China.The first study on microplastic pollution in the Liaohe River Reserve in Northern China is reported here,and mesoplastics were also incorporated.Surface water and sediment samples were collected from 32 sites along the nature reserve.The abundance,type,shape,color,and size of micro-and mesoplastics were measured using density extraction,optical microscopy,and FTIR spectroscopy.The data showed that diverse micro-and mesoplastics were found widespread in the 32 sites,and the average abundance of these plastics was 0.11±0.0410^(–2) items/L in surface water and 62.29±54.30 items/kg in sediment.Moreover,70%and 66%were smaller than 2000μm in surface water and sediment,respectively.Fiber accounted for 91.86%in surface water and 43.48%in sediment,indicating that the major source of micro-and mesoplastics in the Liaohe River Reserve may be domestic sewage and aquaculture.A total of 16 and 27 polymers were identified in surface water and sediment,respectively,and mostly consisted of rayon,polyester,polystyrene,and poly(ethylene terephthalate).Moreover,both the risk index and the pollution load index demonstrated a low risk of micro-and mesoplastics in surface water and sediment in the Liaohe River Reserve.

Terrestrial ecosystem health under long-term metal inputs:modeling and risk assessment

Metal contamination of soils may pose long-term risks to ecosystem health if not proper-ly managed.Future projection of contamination trends,coupled with ecological assessment,is needed to assess such risks.This can be achieved by coupling dynamic models of soil metal accumulation and loss with risk assessment on the basis of projected metal levels.In this study,we modeled the long-term dy-namics of Cu,Zn,and Cd in agricultural topsoils of a northern Chinese catchment(Guanting reservoir)and related projected metal levels to 2060 to ecological risk.Past metal dynamics were simulated using historical metal inputs from atmospheric deposition,irrigation,fertilizers,and animal manures.Model-ing future dynamics was done using scenarios of projected metal input rates.Ecological risk assessment was done using the Potentially Affected Fraction(PAF)approach to estimate the combined toxic pressure due to the three metals.Modeled labile soil metals agreed well with measurements from monitoring in 2009 following adjustment of the porewater dissolved organic concentration.Metals were predicted to be largely retained in the topsoil.Projections were sensitive to changes in imposed soil pH,organic mat-ter,and porewater dissolved organic carbon.Modeling suggests that decreases in input rates to between 5%and 7.5%of 2009 levels are required to prevent further accumulation.Computed PAFs suggest zinc makes the greatest contribution to ecological risk.Under the most conservative estimate of PAF,the threshold of potential ecological risk was reached before 2060 in two of the three future input scenarios.