Remediation of internal phosphorus loads with modified clays, influence of fluvial suspended particulate matter and response of the benthic macroinvertebrate community

Hongbin Yin; Grant B Douglas; Yongjiu Cai; Cheng Liu; Diego Copetti

doi:10.1016/j.scitotenv.2017.07.243

Remediation of internal phosphorus loads with modified clays, influence of fluvial suspended particulate matter and response of the benthic macroinvertebrate community

Sci Total Environ. 2018 Jan 1:610-611:101-110. doi: 10.1016/j.scitotenv.2017.07.243. Epub 2017 Aug 10.

Authors

Hongbin Yin¹, Grant B Douglas², Yongjiu Cai³, Cheng Liu³, Diego Copetti⁴

Affiliations

¹ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, 210008 Nanjing, China. Electronic address: hbyin@niglas.ac.cn.
² CSIRO Land and Water, Centre for Environment and Life Sciences, Private Bag 5, Wembley, WA 6913, Australia.
³ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, 210008 Nanjing, China.
⁴ Water Research Institute, National Research Council of Italy, IRSA-CNR, Via del Mulino, 19, 20861 Brugherio, MB, Italy.

PMID: 28803188
DOI: 10.1016/j.scitotenv.2017.07.243

Abstract

Clay-based phosphorus (P) sorbents have been increasingly used as geoengineering materials for the management sediment-derived internal P loading in eutrophic lakes. However, the long-term behavior of these sorbents has remained elusive along with their response to burial under suspended particulate matter (SPM), and their effect on macroinvertebrate communities occupying dynamic regions at the sediment-water interface of shallow and turbid lakes. In this study, field mesocosm experiments were undertaken in Lake Chaohu, China, to study the effects of the application of lanthanum-modified bentonite (LMB) and thermally-modified calcium-rich attapulgite (TCAP) on sediment internal P loading and to assess their influence on macroinvertebrate community structure. A complementary laboratory core incubation study was also undertaken to investigate the effects of SPM deposition on LMB and TCAP performance. In the field, both LMB and TCAP effectively intercepted P released from sediment for up to five months. A P fractionation analysis indicated that LMB and TCAP application results in a substantial increase in inert P fractions in sediment. Laboratory studies indicated that deposition of SPM may increase in mobile P both in the upper sediment and across the new post-SPM deposition sediment-water interface. Importantly, a comparison of sediment chemical extractions and estimated P fluxes suggests that chemically-defined forms of P in the sediment may be used as a proxy to estimate the net sediment P flux. Significantly, the surficial application of either LMB or TCAP did not cause negative effects on macroinvertebrate communities. This study indicates that to sustain a low P flux across the sediment-water interface in shallow, turbid lakes, repeat dosing of geoengineering materials, temporally aligned to the deposition of fluvial SPM, may be required.

Keywords: Benthic macroinvertebrate community; Geoengineering materials; P flux; Sediment internal P management; Suspended particulate matter.