The trophic linkage between zooplankton and benthic suspension feeders: direct evidence from analyses of bivalve faecal pellets

Using radiotracer (¹⁴C) and microscopic observation, we demonstrated that mussels (Mytilus edulis and Perna viridis) could be predators of mesozooplankton (rotifer Brachionus plicatilis). At radio-labelled rotifer densities of 0.1, 0.2, 0.5, 1.0 individual ml⁻¹, faecal pellets of mussels showed different degrees of radio signals and most of the faecal pellets were expelled 4 h after pulse feeding on rotifers. The maximum gut retention time (GRT) of ¹⁴C-labelled rotifers in the digestive diverticula did not o show any significant difference between the two mussel species or the different densities of rotifers, and the averaged GRT was 43.4±3.06 h (mean ± SE). At a rotifer density of 4.5 individual ml⁻¹, rotifer lorica pieces and rotifer bodies without eggs were found in faeces of M. edulis, while in the pseudofaeces, only complete rotifer bodies were found.     

Is the effect of quantified road safety targets sustainable?

Recent studies have shown that the setting of road safety targets is associated with a substantial reduction in road fatalities in the short-term. Although such targets may not themselves be responsible for the reduction in fatalities, they serve as a useful measure of the intention and commitment of road authorities to formulate timely road safety measures that lead to the achievement of the target. A quantified target is regarded as one of the key components of a road safety strategy. However, few studies have examined the degree of commitment and attention of road authorities to such targets in the long-term. In this study, we revisit the effectiveness of the quantified road safety targets set by the Organisation for Economic Co-operation and Development (OECD) countries, but with a different method, time scale, and group of comparison countries. We not only evaluate the associations between quantified targets and road fatality levels, but also measure the changes in the time-series trends in road fatalities over the long-term. The results indicate that all seven treatment countries analyzed experienced desirable changes in the time-series trend in road fatalities during the period under study, which implies an increase in road safety improvement over time.     

Biota–sediment accumulation factor (BSAF), bioaccumulation factor (BAF), and contaminant levels in prey fish to indicate the extent of PAHs and OCPs contamination in eggs of waterbirds

Samples of pond sediment, fish, and shrimp were collected from the Ramsar site at Mai Po marshes, Hong Kong (south China), and samples of pond sediment, fish, and shrimp, as well as eggs of water birds (Chinese Pond Herons (Ardeola bacchus) and Little Egrets (Egretta garzetta)), were collected from two smaller wetland sites at Jiangsu Province (mid-China), between 2004 and 2007. Accumulation levels of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the biota were used to calculate biota–sediment accumulation factor (BSAF) and bioaccumulation factor (BAF). For fish and shrimp, BSAFs of OCPs (3.8–56) were greater than those of PAHs (0.12–6.3). BSAFs and BAFs of 11–79 and 4–34, respectively, were registered for OCPs in eggs of the birds and were greater than those for PAHs (0.11–1.5 and 0.02–1.3, respectively). Assuming that fish were the main prey of the birds, greater bioaccumulation of OCPs was detected for both bird species (BAFs?=?4.5–34), while accumulation of PAHs was only detected in Little Egret (BAF?=?1.3). A significant linear relationship (p?<?0.01) was observed between concentrations of OCPs in bird eggs and in the prey fish. The present study provides a new possibility of using OCP levels detected in prey fish to predict the extent of OCPs contamination in eggs of waterbirds including the endangered species, as a noninvasive method.     

Describing variability of MSW composition data with the log-logistic distribution

Variations in solid waste composition data are necessary as inputs to solid waste planning, yet uncertainty exists regarding which probability distributions might be generally valuable to describe the variability. Twenty-two detailed analyses of solid waste from British Columbia, Canada, were fitted to distributions using the BestFit software. Alternative distributions were ranked based on three goodness-of-fit parameters and twelve waste fractions. The log-logistic distribution was found to be the most able to fit over the wide range of composition types considered. The results were demonstrated to be insensitive to the number of waste components or to the choice of a two- or three-parameter distribution. Although other distributions were able to better match the waste composition for individual waste types, the log-logistic distribution was demonstrated to fit, overall, a wide variety of waste composition types.     

The effects of 2,4-D herbicide and organophosphorus insecticides on growth, photosynthesis, and chlorophyll a synthesis of Chlamydomonas reinhardtii (mt +)

The effects of the herbicide (2,4-D) and six organophosphorus insecticides (Diazinon, Dimethoate, Fenitrothion, Malathion, Phenthoate and Quinalphos) on growth, photosynthesis and chlorophyll a synthesis of the fresh water green alga Chlamydomonas reinhardtii (mt +) were studied. At low concentrations (1 and 5 ppm), the herbicide and all six orgnophosphorus insecticides stimulated photosynthesis of the alga. The stimulating effects on algal growth and chlorophyll a synthesis were only observed in the presence of low concentration (1 ppm) of 2,4-D and Fenitrothion, Growth, photosynthesis and chlorophyll a synthesis of the alga were inhibited in the presence of high concentrations (10, 20 and 40 ppm) of the herbicide and all the six organophosphorus insecticides. Results also indicated that the toxicities of these organophosphorus insecticides on the tested alga were dependent on their chemical structures.     

Trace Metal Contents (Al, Cu and Zn) of Tea: Tea and Soil from Two Tea Plantations, and Tea Products from Different Provinces of China

The present project aims to investigate the possible contamination of teas with the trace metals: Al, Cu and Zn. Tea bushes sampled from two tea plantations in the northern part of Guangdong Province accumulated higher concentrations of Cu and Zn in young leaves, and of Al in old leaves. The analysis of the three metals in tea produced in different provinces indicated higher Al levels in those obtained from Guangdong and Yunnan Provinces, which may be due to the lower soil pH in these areas. Green tea had the lowest Al concentration among the four types of tea studied, as only the bud and two young leaves are used, whereas older leaves are used for other types of tea (black, Oolong and Puerh tea). The transfer of Al, Cu and Zn from soil to different parts of tea bushes was low in general, except for Zn at Lechang tea plantation which next to a Pb/Zn mine, where a higher transfer was observed from young leaves to tea products, indicating possible metal contamination during tea processing. However, low concentrations of Cu and Zn (less than 0.07 mg Cu L^-1 and 0.17 mg Zn L^-1), and moderate amounts of Al (2.1-2.5 mg L^-1) were obtained in the tea liquor (1% hot water extracts).     

Shark fin,a symbol of wealth and good fortune may pose health risks: the case of mercury

There is a lack of information concerning human health risks due to exposure to mercury contained in shark fins, through dietary intake. Health risk assessment of shark fins, collected from 5 cities in China: Hong Kong (HK), Beijing, Shanghai (SH), Haikou (HN) and Wenzhou (WZ), was conducted, based on total mercury and methylmercury, and analyzed by a cold vapor atomic fluorescence spectrometry equipped with high-performance liquid chromatography, respectively. The results showed that 16.8 % samples from HK, 8.3 % from SH, 33.3 % from HN, and 16.8 % from WZ were regarded as unsafe for human consumption. Extremely high consumption rates of shark fins for an adult and a child (0.150 and 0.0807 kg/day, respectively), at 95th centile, samples from WZ demonstrated high non-cancer risks (adverse health effects) (Hazard Quotient = 16.0) on adults (aged 25–65), and samples from SH, HN and WZ also showed high non-cancer risks (Hazard Quotient = 12.9, 21.0, and 34.4, respectively) on children (aged 1–7). Consumption of shark fins may be detrimental to human health.