White hard clam (Meretrix lyrata) shells as novel filter media to augment the phosphorus removal from wastewater.

It is well recognized that filter media play a crucial role in constructed wetlands (CWs) for decontamination of phosphorus (P)-rich wastewater. This study investigates the suitability of raw white hard clam shells (WHC) and white hard clam shells thermally modified at 800 °C (WHC-M800) as potential media to enhance P treatment performance in CWs. The results indicated that both WHC and WHC-M800 displayed appropriate physicochemical properties, such as high porosity, excellent hydraulic conductivity, and rich Ca content. WHC-M800 exhibited a superior P adsorption capacity (38.7 mg/g) to WHC (12.8 mg/g). However, the practical utilization of WHC-M800 as filter media in CWs may be compromised, due to certain limitations, for example: extremely high pH values in the post-adsorption solutions; high weight losses during calcination and adsorption processes; low mechanical strength; and intensive energy consumption. In contrast, the WHC demonstrated significant advantages of reasonably high P adsorption capacity, locally abundant availability, low cost, and marginal side effects. The fractionation of inorganic P of WHC and WHC-M800 revealed that Ca-bounded P was the most dominant binding form, followed by loosely bound P, Fe-P, occluded P, and Al-P. The present study demonstrates that recycling of WHC shells as a potential substrate in CWs provides a feasible method for upgrading P removal in CWs. Additionally, it helps to reduce waste WHC shells in a simple, cheap, and eco-friendly way, thus can double environmental benefits.

[Population genetic structure of wild-growing ginseng (Planax ginseng C. A. Meyer) assessed using AFLP markers].

Genetic variability in ten populations of wild-growing ginseng was assessed using AFLP markers with the application of fragment analysis on a genetic analyzer. The variation indices were high in the populations (P = 55.68%; H(S) = 0.1891) and for the species (P = 99.65%; H(S) = 0.2857). Considerable and statistically significant population differentiation was demonstrated (theta = 0.363; Bayesian approach, "full model"; F(ST) = 0.36, AMOVA). The results of AMOVA and Bayesian analysis indicate that 64.46% of variability is found within the populations. Mantel test showed no correlation between the genetic and geographic distances among the populations (r = -0.174; P = 0.817). Hierarchical AMOVA and analysis of genetic relationships based on Euclidean distances (NJ, PCoA, and MST) identified two divergent population groups of ginseng. Low gene flow between these groups (N(m) = 0.4) suggests their demographic independence. In accordance to the concept of evolutionary significant units (ESU), these population groups, in terms of the strategy and tactics for conservation and management of natural resources, should be treated as management units (MUs). The MS tree topology suggests recolonization of southern Sikhote-Alin by ginseng along two directions, from south and west.