Phytotoxicity and Accumulation of Antibiotics in Water Lettuce (Pistia stratiotes) and Parrot Feather (Myriophyllum aquaticum) Plants under Hydroponic Culture Conditions

The aim of this research was to investigate the accumulation of antibiotics in two kinds of plants. The hydroponic culture solution included a mixture of antibiotics, including three commonly used antibiotics in South Korea: norfloxacin (NOR), sulfamethazine (SMZ), and tetracyclines (TC). None of these antibiotics were detected in the shoots of water lettuce plants, only in the roots. However, in parrot feather plants, antibiotics were detected in both the shoots and the roots, with higher amounts detected in the shoots than in the roots. SMZ and TC were most likely to be detected in the roots and shoots of water lettuce and parrot feather plants, and about one-third of the NOR administered was later detected in the plants. The BCF (bioconcentration factor) of antibiotics ranged from 0.24 to 0.78, while that of NOR was much lower, ranging from 0.24 to 0.38. The SMZ (0.59–0.64) and TET (0.72–0.78) exhibited higher uptake accumulation in the water lettuce tissues compared with the parrot feather plants.

Myriophyllum aquaticum (parrot's feather).

M. aquaticum (parrot-feather) is an invasive submerged/emergent aquatic weed characteristic of sub-tropical to warm-temperate regions, but found as far north as the UK (recorded from at least 33 countries: native to perhaps 6 of these, all in South America). It was recorded as an alien as early as 1906 in Florida, and 1919 in South Africa. It is a particular problem of small water bodies, irrigation channel networks, and small streams, where it primarily impedes flow and causes a range of associated environmental problems, such as water deoxygenation. Long-distance spread via the aquarium/garden trade has been a notable anthropogenic vector. Once introduced to a new region it spreads rapidly, primarily by vegetative stem fragmentation, male plants are rarely recorded outside the native range so seed production is (so-far) negligible as a vector. It is listed as a notifiable/prohibited weed in many countries and states worldwide.

Farewell to the Gods

A pre-Columbian building decorated with polychrome mural paintings was recently discovered at the site of Pachacamac, near Lima. Hundreds of offerings were scattered across the rooms and corridors of the building. They included extremely diverse objects from across the Andean region: parrot feather adornments and seeds from the Amazon; black stones from the mountains, chosen for their unusual shapes; unmodified and sculpted shells from the Equatorial region; ornate cups inlaid with mother-of-pearl in the style of the Northern Coast; metal; Inca ceramics, etc. In this chapter, the use of this peculiar building—probably a kind of sanctuary—and its links with pilgrimage, healing practices, and ancestor cult are discussed. Most of the offerings were placed within and around the structure at the moment of its abandonment following the Spanish invasion. The possible meanings and causes of such an unusual ritual are reviewed and discussed.

Balancing Fisheries Management and Water Uses for Impounded River Systems

<em>Abstract</em>.—Lake Austin is a 648-ha riverine impoundment of the Colorado River located in central Texas and supports a trophy ($5.9 kg minimum weight) largemouth bass <em>Micropterus salmoides </em>fishery. Much of the reservoir is bordered by waterfront homes and, in addition to largemouth bass anglers, also is used by recreational boaters. Aquatic vegetation management on this reservoir has been an issue of concern since the 1950s. Parrot feather <em>Myriophyllum aquaticum </em>and Eurasian watermilfoil <em>M. spicatum </em>were the traditional species of concern but were successfully controlled with winter drawdowns. In 1999, hydrilla <em>Hydrilla verticillata </em>(9 ha) was documented for the first time, and by 2002, coverage had expanded to 130 ha. A hydrilla management plan was developed by a multistakeholder group that included biological (including triploid grass carp <em>Ctenopharyngodon idella</em>), mechanical, physical (reservoir drawdowns), and chemical management options. Of these options, most attention was given to the use of triploid grass carp. Many waterfront property owners viewed grass carp as the only reasonable solution, while largemouth bass angling groups vehemently opposed this management option. After much discussion, the stakeholder group decided that a slow methodical approach to triploid grass carp use, with a number of incremental stockings, might have a chance of successfully reducing hydrilla coverage without denuding the reservoir of all aquatic vegetation. The strategy was to increase the number of grass carp slowly until there were just enough in the reservoir to control hydrilla but not so many as to eliminate less preferred plant species. After an initial stocking in February 2003, the number of additional grass carp stocked was based on results of hydrilla coverage surveys conducted at 2–4-month intervals during the growing season. From February 2003 through November 2004, a total of 8,125 triploid grass carp were stocked in six stockings. The number of grass carp per hectare of hydrilla ranged from 29.2 to 68.3 until coverage declined in December 2004 to 34 ha. From February 2005 to March 2007, hydrilla coverage ranged from only 1 to 27 ha (0.1–4.2% coverage) while other plant species less preferred by grass carp, primarily Eurasian watermilfoil expanded. As a result, mean total vegetation coverage from February 2005 to March 2007 was 17% and continued to provide habitat for largemouth bass. Grass carp stockings were reinitiated in October 2006 when hydrilla coverage increased to 27 ha. In 2005 and 2006, the incremental stocking strategy implemented at Lake Austin appeared to help control hydrilla without denuding the reservoir of all aquatic vegetation. Cooperators and interest groups seemed satisfied with the strategy and results.