Aquaculture practices and potential human health risks: current knowledge and future priorities

Annual global aquaculture production has more than tripled within the past 15 years, and by 2015, aquaculture is predicted to account for 39% of total global seafood production by weight. Given that lack of adequate nutrition is a leading contributor to the global burden of disease, increased food production through aquaculture is a seemingly welcome sign. However, as production surges, aquaculture facilities increasingly rely on the heavy input of formulated feeds, antibiotics, antifungals, and agrochemicals. This review summarizes our current knowledge concerning major chemical, biological and emerging agents that are employed in modern aquaculture facilities and their potential impacts on public health. Findings from this review indicate that current aquaculture practices can lead to elevated levels of antibiotic residues, antibiotic-resistant bacteria, persistent organic pollutants, metals, parasites, and viruses in aquacultured finfish and shellfish. Specific populations at risk of exposure to these contaminants include individuals working in aquaculture facilities, populations living around these facilities, and consumers of aquacultured food products. Additional research is necessary not only to fully understand the human health risks associated with aquacultured fish versus wild-caught fish but also to develop appropriate interventions that could reduce or prevent these risks. In order to adequately understand, address and prevent these impacts at local, national and global scales, researchers, policy makers, governments, and aquaculture industries must collaborate and cooperate in exchanging critical information and developing targeted policies that are practical, effective and enforceable.     

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.     

Distributions of heavy metals in the surface sediments of the Gulf of Saros, NE Aegean Sea

The Gulf of Saros in the northeastern Aegean Sea (Turkey) is a relatively unpolluted marine environment. There is almost no industry and only small settlements in the surrounding region. The main sources of fresh water and sediment to the Gulf are the Meric River in the northwest and the Kavak Creek in the east. It has an asymmetric bathymetry with a 10-km-wide shelf to the north and up to 15-km-wide, 700-m-deep trough in the south. Water circulation in the Gulf is characterized by longshore currents and anticyclonic eddies. The Black Sea waters, leaving the Sea of Marmara through the Canakkale Strait, are known to enter the southern Gulf during the summer. The surface sediments on the northern shelf consist mainly of sand, whereas those on the slope and the deep trough are mainly silt and clay. The ranges of Fe, Mn, Cu, Zn, Pb, Ni, and Hg contents of the surface sediments from the Gulf of Saros are 0.25 4.60%, 114 1740 ppm, 6-44 ppm, 23-154 ppm, 2-80 ppm, 14-145 ppm, and 10-130 ppb, respectively. These values are low compared to those from the other neighboring marine environments, indicating the pristine nature of the Gulf in terms of metal pollution. However, most metal and organic carbon (Corg) distributions in the Gulf sediments show the effect of anthropogenic and natural inputs to the northwestern and eastern shelf areas from the Meric River and the Kavak Creek and to the deep trough from the Black Sea waters.     

Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (<63 micro particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies.     

Recent socio-economic changes in relation to environmental quality of the Pearl River delta

Due to the favorable weather, abundant water resources and fertile soil, the area has been known as the homeland for crops and fish. However, being one of the most developed regions in China, the environmental quality of the Pearl River delta has deteriorated due to recent socio-economic changes during the past two decades. The drivers are industrialization and economic growth, population growth and agricultural development; and the pressures are water pollution which include nutrients and suspended solids, pesticides, other persistent toxic substances (PAHs and PCBs) and oil. These have imposed various impacts such as eutrophication, formation of red tides and biomagnification of organic contaminants through food chains. In response to these, regulatory measures have been established by the Environmental Protection Bureau of Guangdong Province, joining forces with environmental protection authorities in all urban cities and most counties, in addition to the Hong Kong Environmental Protection Department, to control pollution in order to prevent further environmental deterioration and economic loss. The present paper is an attempt by following the DPSIR approach promoted by the OECD in the early 1990s and further developed by IGBP LOICZ to review the environmental quality of Pearl River with emphasis on water quality and the impact of rapid socio-economic changes.     

The Use of Natural Taraxacum officinale Wigg. Populations for Assessing the State of Technogenically Disturbed Areas

Russian Journal of Ecology -     

Arsenic geochemistry and health

Arsenic occurs naturally in the earth's crust and is widely distributed in the environment. Natural mineralization and activities of microorganisms enhance arsenic mobilization in the environment but human intervention has exacerbated arsenic contamination. Although arsenic is useful for industrial, agricultural, medicinal and other purposes, it exerts a toxic effect in a variety of organisms, including humans. Arsenic exposure may not only affect and disable organs of the body, especially the skin, but may also interfere with the proper functioning of the immune system. This paper, therefore, generally highlights the toxic effects of arsenic as well as its mobilization in the natural environment and possible controls. It also briefly attempts to outline the impact of arsenic on the immune system, whose alteration could lead to viral/bacterial infections.     

Getting caught up in the game: managing non-formal dynamics in the remediation of contaminated sediments in Oslo harbor

This study aims at describing, analyzing and evaluating the relation between management styles and process dynamics of a complex planning process confronted with unexpected dynamics. The development of an aquatic disposal site for dredged contaminated sediments in Oslo was managed by a project management style focused on timely and cost-effective implementation. Coupling the remediation project with another infrastructural project and the actual construction of the site led to unexpected dynamics in terms of resistance and controversy. Project management had difficulties in adjusting its style accordingly, resulting in even more delay and resistance. Managing complex planning projects requires a style suitable to the characteristics of the project and the capability of adjusting it to changing circumstances. The paper concludes with some explanations why it is difficult to change management styles in complex planning and implementation processes and complexity-embracing approaches to deal with this.