scholarly journals Potentially toxic trace element pollution in long-term fertilized agricultural soils in China: a meta-analysis

Author(s):  
Shiwei Zhou ◽  
Shu Su ◽  
Ling Meng ◽  
Xiao Liu ◽  
Hongyuan Zhang ◽  
...  
1994 ◽  
Vol 2 (2) ◽  
pp. 133-146 ◽  
Author(s):  
Bal Ram Singh

Fertilizers, along with atmospheric deposition, are believed to contribute more than all other factors to the trace element burden of cultivated soils. This review will discuss trace elements in commercial fertilizer in relation to their transfer to soil–plant systems. Also, background levels in soils and the concentrations of trace elements in soils, phosphate rocks, and commercial fertilizers will be presented. Results from several short and long-term experiments indicated that the application of phosphate fertilizers to agricultural soils generally resulted in an increase of trace elements in soils and that the increase was most pronounced for Cd. The corresponding increase in plants was quite variable, ranging from no increase at all to a significant increase. The concentration of trace elements in plant species also showed a wide variation. The distribution and partitioning of trace elements among chemical associations in soils varied considerably for different elements. The highest percentage of Cd in soils, as estimated by sequential extraction, was associated with exchangeable fractions (25–41%), but the highest fraction of Zn (47%) was associated with resistant minerals. Uptake of trace elements by plants and solubility and mobility of these elements in the soil were affected to a greater extent by the plant species grown and soil pH, organic matter, and soil texture. Soil pH showed a significant but inverse relationship with the concentrations of most of the trace elements in plants. The addition of organic matter generally immobilized the trace elements in soils and caused reduction in plant uptake of most elements. A considerable proportion (up to 50%) of the total uptake of trace elements, and especially of Cd, was a result of atmospheric deposition. Ecological implications of contaminants in fertilizers and the resultant need for research are described.Key words: accumulation in soils, fertilizers, plant availability, soil properties, trace elements.


Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1716 ◽  
Author(s):  
Yaqi Hu ◽  
Wenyong Wu ◽  
Di Xu ◽  
Honglu Liu

The rapid increase of reclaimed water irrigation on agricultural soils requires investigation of its impact on soil health. In this study, a simulation experiment for various lengths of long-term reclaimed water irrigation time (98, 196 and 236 years, respectively) was conducted in the southeast suburb of Beijing, China. Unirrigated soil served as the control. The environmental behavior of seven trace elements (As, Cd, Cr, Cu, Hg, Pb and Zn) at different soil depths in 0–600 cm profiles was analyzed. Results showed that the 0–30 and 200–300 cm soil layers were more likely to accumulate trace elements under long-term reclaimed water irrigation, although the accumulation in the 0–600 cm profiles was not particularly obvious. Correlation analysis showed that the trace element concentrations and distribution were significantly related to clay fraction and organic matters (OM), whereas they were not related to redox potential (Eh). The potential ecological risk assessment showed that the long-term reclaimed water irrigation did not result in a significantly increased ecological risk. However, Cd and Hg were identified as the metals with the highest potential ecological risk in the study area and the trace element contents in the top 0–30 cm soil layer should be carefully monitored. Future studies are required to clarify the environmental risks of trace elements under long-term reclaimed water irrigation as they might slowly accumulate in soil with time.


2020 ◽  
Author(s):  
Hanna Algattas ◽  
Pradeep Setty ◽  
Ezequiel Goldschmidt ◽  
Eric W. Wang ◽  
Elizabeth Tyler-Kabara ◽  
...  

2019 ◽  
Vol 24 (5) ◽  
pp. 558-571 ◽  
Author(s):  
Kartik Bhatia ◽  
Hans Kortman ◽  
Christopher Blair ◽  
Geoffrey Parker ◽  
David Brunacci ◽  
...  

OBJECTIVEThe role of mechanical thrombectomy in pediatric acute ischemic stroke is uncertain, despite extensive evidence of benefit in adults. The existing literature consists of several recent small single-arm cohort studies, as well as multiple prior small case series and case reports. Published reports of pediatric cases have increased markedly since 2015, after the publication of the positive trials in adults. The recent AHA/ASA Scientific Statement on this issue was informed predominantly by pre-2015 case reports and identified several knowledge gaps, including how young a child may undergo thrombectomy. A repeat systematic review and meta-analysis is warranted to help guide therapeutic decisions and address gaps in knowledge.METHODSUsing PRISMA-IPD guidelines, the authors performed a systematic review of the literature from 1999 to April 2019 and individual patient data meta-analysis, with 2 independent reviewers. An additional series of 3 cases in adolescent males from one of the authors’ centers was also included. The primary outcomes were the rate of good long-term (mRS score 0–2 at final follow-up) and short-term (reduction in NIHSS score by ≥ 8 points or NIHSS score 0–1 at up to 24 hours post-thrombectomy) neurological outcomes following mechanical thrombectomy for acute ischemic stroke in patients < 18 years of age. The secondary outcome was the rate of successful angiographic recanalization (mTICI score 2b/3).RESULTSThe authors’ review yielded 113 cases of mechanical thrombectomy in 110 pediatric patients. Although complete follow-up data are not available for all patients, 87 of 96 (90.6%) had good long-term neurological outcomes (mRS score 0–2), 55 of 79 (69.6%) had good short-term neurological outcomes, and 86 of 98 (87.8%) had successful angiographic recanalization (mTICI score 2b/3). Death occurred in 2 patients and symptomatic intracranial hemorrhage in 1 patient. Sixteen published thrombectomy cases were identified in children < 5 years of age.CONCLUSIONSMechanical thrombectomy may be considered for acute ischemic stroke due to large vessel occlusion (ICA terminus, M1, basilar artery) in patients aged 1–18 years (Level C evidence; Class IIb recommendation). The existing evidence base is likely affected by selection and publication bias. A prospective multinational registry is recommended as the next investigative step.


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