The results of the LMB application presented in this review underline a strong efficiency of this product in reducing the SRP concentrations in the water column and the P flux from sediments. This efficiency has been confirmed in laboratory, mesocosm and field trials. However, in the presence of high DOC concentrations SRP removal can be limited (Douglas et?al., 2000, Lürling et?al., 2014 and Dithmer et?al., 2016) or even absent (Geurts et al., 2011). Also the interference with oxyanions other than PO4 was highlighted as a confounding factor (e.g. Reitzel et al., 2013a). However, in a recent study Dithmer et al. (2016) did not find any correlation between alkalinity and P binding capacity of the LMB. Apart from these limitations the LMB efficiently binds SRP in fresh water ecosystems and over a wide range of physico-chemical conditions, with particular respect to pH. Maximum efficiency in P binding has been found in a 5–7 LHRH
range, while the efficiency decreases markedly at pH higher than 9. Such high pH values are generally indicative of strong photosynthetic activity (potentially due to both macrophytes and phytoplankton) in eutrophic lakes. Under these conditions (and in particular during algal blooms) the sole LMB application is not recommended, because of the commonly observed high pH and low SRP concentrations, making timing a crucial component of the application. Usually winter in temperate regions will offer the best window of opportunity with probably least side effects on biota. Also the use of this product in saline environments, cannot be a priori recommended due to potential lanthanum release as underlined by pre-commercialization studies (Douglas personal communication). In this way synergid
has to be underlined that data on the LMB behaviour in saline or brackish waters are scarce. In one of the few studies available, however, Reitzel et al. (2013a) found only a slight increase (<1%) of filtered TLa (La < 0.2 ?m), a 5% increase of unfiltered TLa (La > 0.2 ?m) and 9% of TLa adhering to the walls of the plastic tubes used in their tests in moderately saline water (15 ppt). These results indicate leakage of La from the clay matrix in moderate salinity water of about 15%. At the moment the application of this product in even moderately saline environments need a careful risk and case by case evaluation. The results presented in this review allow to generalize this concept and to highlight the importance of carefully plan any field application and trial. In this way the results of the Deep Creek Reservoir are emblematic (NICNAS, 2014). A LMB trial was conducted in Deep Creek Reservoir, Australia in 2007 ( Chapman et?al., 2009 and NICNAS, 2014). In this trial an approximately three times overdosing of LMB based on FRP concentrations occurred with a resultant maximum concentration of dissolved La of
220 ?g L−1. Addition also occurred of other non-LMB agents that may have compromised the trial integrity. Temporally-associated fish mortalities occurred for up to two weeks post reagent application (NICNAS, 2014). Few living zooplankton individuals were identified in the reservoir seven weeks post-LMB application (NICNAS, 2014) with a possible link postulated between the LMB application and lethal effects on aquatic biota from two trophic levels.