Time:2021-10-22 Reading:9858
Agricultural films are
the fourth largest agricultural production material after seeds, fertilizers,
and pesticides, and are widely used in China. Plasticizer is an important
agricultural film additive that can be released in the environment and pollute
the environment.
Recently, Qianqin Zhang, associate researcher of Professor Guangguo Ying team in SCNU Environmental Research Institute of South China Normal University. comprehensively described the amount of agricultural films used in China and the environmental residues of its plastic debris and assessed the release and environmental fate of phthalate esters (plasticizers) in the whole life cycle of agricultural film use. The study was published in Environmental Science and Technology.
China's annual
agricultural film recycling rate is less than 2/3
Annual growth of 6.5%
and 5.9% for ground and shed films.
The team analyzed the use of agricultural films (ground and trellis films) in China from 1997 to 2017 based on a combination of big data collection, laboratory testing, and model simulation, and assessed the amount of plastic debris remaining and migrating from agricultural films after use and partial recycling.
The results showed that
in 2017, China's agricultural plastic film use was 2,528,600 tons; after the
agricultural film recycling and soil erosion process, the agricultural plastic
residue amounted to 465,016 tons, while 4,329 tons of plastic debris into the
aquatic environment and discharged into the oceans in soil erosion process.
Construct two models.
"Based on the fugacity approach, we constructed a ground-film cover model and a shed-film semi-elliptical plastic tunnel model to simulate the multi-media environmental levels of dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) in each province, as well as transport fluxes between each environmental medium. The predicted concentrations of the target plasticizers in agricultural fields were slightly lower than the published concentrations in various provinces, suggesting the contribution of other sources of plasticizers in the agricultural environment." Guangguo Ying said.
Flux analyses showed that the main output fluxes of DBP and DEHP from ground films are degradation. For shed films, 60.9% of the released DBP would be degraded, while 96.3% of DEHP would accumulate in vegetables. However, the assessment showed that the consumption risk of plasticizers in greenhouse vegetables is low.
According to the report, in 2017, 18.8 tons of DBP and 42.2 tons of DEHP were released from the ground film in China. Among them, 7.53 tons and 16.9 tons entered the atmospheric environment, respectively, and the rest entered the soil environment. The releases of the two typical plasticizers showed significant regional characteristics.
The provinces and regions with the largest releases are Xinjiang, Gansu, Shandong, Inner Mongolia and Yunnan, whose total releases can reach more than 50% of the national emissions. The amount of plasticizer release is the lowest in Tibet.
In 2017, 5.94 tons of DBP and 24.5 tons of DEHP were released from shed films.
Among them, 50~51.6%
were released inside the greenhouses and enriched in the vegetables and soil,
and the rest released into the external environment. The influence of
temperature on the release of plasticizers was significant, as evidenced by the
ratio of the release of plasticizers inside and outside the greenhouses in the
northeastern and northwestern provinces and regions being 1.06:1, while that in
the warm and humid southern China region was 1.009:1.
Article reprinted from WeChat's China Science Daily, by Zhu Hanbin