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Drip irrigation is a valuable method for optimising water and fertiliser usage, motivating its increasing use. However, the ecological effects of drip irrigation fertilisation have not been sufficiently evaluated, limiting its effective and widespread use. Within this context, we aimed to determine the effects and potential ecological risks of using polyethylene irrigation pipes and mulch substrate under various drip irrigation conditions as well as burning of waste pipes and mulch substrate. Laboratory simulations of field conditions were used to determine the distribution, leaching, and migration pattern of heavy metals (Cd, Cr, Cu, Pb, and Zn) from plastic drip irrigation pipes and agricultural mulch substrate into various solutions. Maize samples obtained from drip-irrigated fields were analysed to determine the presence of heavy metal residues and assess the risk of heavy metal contamination. Heavy metal leaching from pipes and mulch substrate was high under acidic conditions, while the migration of heavy metals from plastic products was low in alkaline water-soluble fertiliser solutions. After combustion, heavy metal leaching from pipes and mulch residues increased considerably, with the migration capacity of Cd, Cr, and Cu increasing by >10-fold. Heavy metals in plastic pipes migrated primarily to the residue (bottom ash), whereas those from mulch substrate migrated to the fly ash component. Under experimental conditions, the migration of heavy metals from plastic pipes and mulch substrate had a negligible effect on the heavy metal content in aqueous environments. Although heavy metal leaching increased, the effect on water quality under actual irrigation conditions was relatively minor (in the order of 10 -9 ). Thus, the use of plastic irrigation pipes and mulch substrate did not result in significant heavy metal contamination and potential risk to the agriculture ecosystem. Our study findings provide evidence for the effective application and widespread promotion of drip irrigation and fertiliser technology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this study., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Pymetrozine has replaced toxic organophosphate pesticides previously used for controlling pests of rice crops in China. Existing data on its environmental behavior are usually related to studies on artificial plots that do not adequately address the natural dynamics and residues in actual field conditions. Therefore, studies under field conditions were carried out to investigate the natural dynamics and residues of pymetrozine in two typical rice-growing areas in China - Hunan and Guangxi provinces. Samples of paddy soil and water were collected in relation to spraying events in the study areas. The quick, easy, cheap, effective, rugged and safe (QuEChERS) method was used to extract pymetrozine residues from the samples by a Waters ACQUITY UPLC (Milford, MA, USA) system interfaced with a triple-quadrupole mass spectrometer (Xevo TQ-D, Waters Corp., USA). The initial deposition of pymetrozine in paddy soils was higher than in paddy waters in both areas. The decay of pymetrozine followed an exponential trend consistent with the first order kinetics. The half-life of pymetrozine in paddy water was determined to be 3.0 and 3.8 days, whereas the half-life in soil was 3.8 and 3.5 days in the Guangxi and Hunan samples, respectively. The decline rates of pymetrozine in paddy soil and paddy water in this field study were faster than those conducted under non-field conditions reported in previous studies. Compared to other pesticides used in China as reported in previous studies, the environmental persistence of pymetrozine in both paddy water and soils in Guangxi and Hunan provinces is very low. This has important implications for the use of pymetrozine in agricultural systems globally., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Water quality is closely associated with human health and socio-economic sustainable development. With the increasingly intensive anthropogenic activities, pollutants especially trace elements, enter water aquatic system and cause harm to humans. This study conducted the first systematic comparison on the pollution status of surface water and groundwater in China. Water quality and health risk assessment of 12 trace elements were evaluated according to the water quality index (WQI), hazard quotient (HQ), hazard index (HI), and carcinogenic risk (CR). The results showed that the average values of trace elements in the majority of surface water were higher than those in groundwater. The WQI values demonstrated that 86.02% of surface water and 83.11% of groundwater were suitable for drinking water. Arsenic served as the predominant pollutant and contributed significantly to cause the non‑carcinogenic risk on human health in both surface water and groundwater, children were more vulnerable to the adverse effects than adults. In surface water, the priority non-carcinogenic risk sites were mainly distributed in Anning River, Taizi River, Middle reaches of Huai River and Jilin section of Songhua River. For groundwater, the high-risk sites were located in Huhhot Basin, Kuitun, Jianghan Plain, Datong Basin and Yucheng County. Arsenic posed potential carcinogenic risk to local resident in some water sites, and it presented higher in groundwater than surface water. More concerns should be paid on Songhua, Yangtze and Huai River Basins, in addition, Pearl, Southeast Coastal, Southwest and Northwest River Basins still need attention. The future work should be carried out more extensive range of the water sites and long-term monitoring in China. In particular, more attention should be dedicated to assess high As water bodies., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)