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Lead (Pb) is a widely occurring heavy metal employed in industrial products and hence released into the environment, causing several environmental health risk concerns. This study comprehensively surveyed the literature on Pb contamination in different agricultural foods and food products commonly consumed by Bangladeshi inhabitants and assessed associated cancer and non-cancer health risks. Cereals (i.e., rice, wheat and maize) contained very high concentrations of Pb among the selected food items, the highest was found in wheat (4.04 µg g−1), while rice and maize were 2.22 and 1.43 µg g−1, respectively, that exceeded the maximum allowable concentration (MAC, 0.20 µg g−1) for cereals. Vegetables contained higher Pb than the MAC of 0.01 µg g−1, except for mushroom, green banana, cauliflower and arum. In addition, pulses also contained a moderate amount of Pb; however, fruits contained a low level of Pb, except for mangoes. When examining spatial differences in Pb contamination, most districts exhibited high Pb content in cereals; however, vegetables of the Tangail district exhibited the highest Pb concentrations (2.17 µg g−1), originating from industrial operations and vehicular emissions. In terms of human health risk assessment, it was observed that consumption of rice, zucchini, tesla gourd, sponge gourd, okra, drumstick lib, chili and cabbage might pose non-cancer health risks (THQs > 1); however, fruits and pulses do not pose any non-cancer health risks to Bangladeshi residents. Most of the cereals and vegetables showed a higher value than 10−6, indicating a potential cancer risk; however, fruits and pulses showed lower risk only marginally exceeding the lower allowable limit (i.e., 10−6). Graphical abstract

Catchment degradation and exposure of acid sulphate soils can affect estuarine water quality, and this can have impacts on the health of estuarine species and adversely affect fishery productivity. In degraded catchments, aluminium (Al) is mobilised from clay minerals following oxidation of acid sulphate soils, and may be harmful to estuarine crustaceans. We tested the acute toxicity and sub-lethal effects of Al for School Prawn (Metapenaeus macleayi), through a series of experiments conducted under normal (pH 8) and acidic (pH 5) conditions. Experimental data were used to examine mortality. Also, histological examination of the gills and hepatopancreas was conducted to determine pathological consequences of exposure to these stressors. School Prawn did not experience mortality in response to acute exposure to Al under normal pH conditions, but mortality and tissue bioaccumulation of Al was greater under acidic conditions, suggesting an interactive effect of both stressors. Histology revealed sub-lethal effects of Al including structural abnormalities in the gills and hepatopancreas, and evidence of viral infection and immune response, particularly at lower pH and higher Al concentrations. These impacts may impede major vital functions such as respiration, osmotic regulation, metabolism and growth of juvenile School Prawn, which could contribute to productivity bottlenecks in degraded estuaries.

Although much previous research effort has examined the impacts of metal contamination on macrobenthic assemblages in subtidal sediments, little attention has been directed at macroinvertebrate responses in intertidal mangrove habitats. Thus, in order to assess the unique responses of mangrove macroinvertebrate assemblages to sediment metal(loid) contamination, total, normalised and bioavailable metal(loid)s (Mn, Pb, Cr, Cd, As, Se, Co, Ni, Zn and Cu) were assessed within and between four mangrove locations in Lake Macquarie, NSW, Australia, and compared to resident macroinvertebrate assemblages over two sampling occasions. Mangrove biomass and physicochemical properties of sediment are known to influence macroinvertebrate assemblages, and as such, were also assessed to account for any potential confounding effect on macroinvertebrate assemblage composition. Significant differences in total and bioavailable metal(loid) contamination were found between and within locations and were consistent over time. Sediments at contaminated locations presented a high risk to biota with bioavailable concentrations of Pb, Cd, Zn found to exceed sediment quality guidelines and concentrations of Se capable of adverse impacts to biota. Macroinvertebrate assemblage composition varied with metal(loid) contamination loads present at study locations. Metal(loid) contamination was significantly correlated with macroinvertebrate assemblages over two sampling periods. Further analysis revealed that 71% of macroinvertebrate assemblage composition could best be explained by a combination of five variables namely, bioavailable Mn, Zn, and Se, number of mangrove seedlings and mean mangrove biomass. Rather than tolerant polychaetes dominating metal(loid)-contaminated sediments (as is found generally in subtidal sediments), polychaetes in intertidal mangroves appeared to be relatively sensitive to metal(loid) stress. Further, decapod crustaceans in the family, Varunidae, and gastropod molluscs, in the family, Amphibolidae, were found to be metal-sensitive taxa and may be employed in future studies as indicator taxa of sediment metal(loid)-related impacts in south-eastern Australian mangrove forests.

Sewage effluent has been identified as a potential source of metal(loid) contamination in the aquatic environment. The Sydney rock oyster, Saccostrea glomerata, can accumulate most metals and is well established as a biomonitor of metals in the marine environment. To determine if Burwood Beach wastewater treatment works (WWTW) is a source of metal(loid) contamination, S. glomerata was deployed for 6 weeks in effluent receiving waters (Burwood Beach near and Burwood Beach far) and at reference locations (Redhead, Fingal Island 1 and Fingal Island 2) at depths 4, 8 and 12 m. In dried oyster tissue, inductively coupled plasma mass spectrometry (ICPMS) was employed to measure concentrations of a suite of metal(loid)s including aluminium, arsenic, cadmium, copper, lead, iron, manganese, mercury, nickel, selenium, silver and zinc. It was found that for all metal(loid)s, S. glomerata tissue concentrations were not significantly higher at Burwood Beach locations in comparison to all reference locations. Concentrations of metal(loid)s were similar to those which have been detected in previous studies of background locations in New South Wales (NSW). Further, all metals fell below National Food Authority maximum residue levels (MRLs), except for arsenic and this does not appear uncommon for concentrations in biota within NSW. Comparisons to historical data suggested that concentrations of metal(loid)s in sewage effluent from Burwood Beach WWTW, assessed via concentrations in oyster tissue, are similar or lower, suggesting that changes in treatment processes initiated in the intervening time have lowered metallic inputs.

Harvesting of wildlife by humans is commonly known to impact target species’ demography, life history and behaviour. Yet in the context of invasive and pest species control, behavioural shifts have received very little attention. The introduced common myna, Acridotheres tristis, is undergoing intensive control efforts in some areas of its Australian distribution. In order to investigate whether myna populations respond to harvesting, we compared the behaviour of free-ranging common mynas in areas of high and low trapping pressure. Behavioural analyses revealed that mynas in high trapping risk areas stayed closer to refuges, tended to form smaller groups, and were overall less detectable. Behavioural differences between high and lowly trapped areas were not attributable to variation in population density. Overall, these results are consistent with the hypothesis that common mynas have the potential to adjust their behaviour in response to heightened anthropic risk in the environment. Behavioural shifts in invasive alien species could modify their ecological impact and may interfere not only with the effectiveness of control measures, but also with how their effectiveness is assessed. Future research should aim to isolate behavioural mechanisms underpinning compensatory responses to control so that any potential effects can be mitigated.

Although mounting evidence suggests exposure to estrogenic contaminants increases vitellogenin production in molluscs, demonstration of dose-response relationships and knowledge of the temporal nature of the vitellogenin response with continual exposure is currently lacking for biomarker utility. To address this knowledge gap, adult Sydney rock oysters, Saccostrea glomerata, were exposed to a range of environmentally relevant concentrations of 17α-ethynylestradiol (EE2) (0, 6.25, 12.5, 25 or 50 ng/l) in seawater under laboratory conditions. Vitellogenin induction and gonadal development was assessed following 4, 21 and 49 days exposure to EE2. Vitellogenin was found to increase in a dose dependent manner with EE2 exposure for females (4 and 49 days) and males (4 and 21 days). Histological examination of gonads revealed a number of individuals exhibited intersex (ovotestis) in 50 ng/l EE2 (after 21 days) and in 6.25 and 12.5 ng/l EE2 (after 49 days). Furthermore, a significant shift towards females was observed following 49 days exposure at 50 ng/l EE2 suggesting estrogenic exposure is capable of facilitating a progression for protandric males from male-intersex-female gametal status. Increases in female vitellogenin (4 days) were predictive of later increases in female developmental stages at 21 days and increases in oocyte area following 49 days. Male vitellogenin (4 days) was predictive of decreased male percentages and lower male developmental stages at 49 days. Vitellogenin in S. glomerata is a predictive biomarker of estrogenic exposure and effect if sampled soon after exposure and at the commencement of a gonadal development cycle.

This study compared the accumulation of arsenic, copper and chromium by Pteris vittata and Pteris umbrosa grown in a glasshouse in soil from a timber treatment facility. Soil was collected from three locations. Accumulation (as percentage removed) varied between these soils but was not related to soil concentration. P. vittata was more efficient than P. umbrosa, both in accumulating As and metals in the below-ground plant parts and in translocating As to the fronds. Under the experimental conditions, only P. vittata could be effectively used in soil from one location for phytoremediation purposes.

Variation in glutathione antioxidant biochemistry in response to metal contamination and accumulation under field conditions was examined in the brachyurid grapsid, Parasesarma erythodactyla. Significant relationships suggesting accumulation were found between sediment metals and metals in crab tissue for Pb, Cu, Cr, Zn, and Se in males and Cd, Pb, Cr Zn, As, and Se in females. Higher pH and lower organic content were associated with greater uptake of selected metals in males and females. Higher salinity was related to increased metal uptake for Cu and Zn in males and lower salinities to increased Se uptake for males and females. When examining metals, which were elevated in crabs, patterns of site discrimination were similar to sediment metal site discrimination for both males and females. In terms of biochemical responses, glutathione levels remained constant while glutathione peroxidase activity was elevated in individuals where metals were elevated. Only females with the highest levels of accumulated metals exhibited increases in lipid peroxidation products. Glutathione peroxidase activity may be a sensitive biomarker of metal exposure and biological effect and lipid peroxides as a secondary marker when accumulated metals are high.

We describe effects of salinity and temperature on germination characteristics of three dominant macrophytes, Phragmites australis, Juncus acutus, and J. kraussii, located in wetlands along the Hunter River, New South Wales, Australia. These wetlands were altered, from estuarine to freshwater habitats, by flood mitigation activities initiated during the 1970s. Tidal restoration to approximately 300 hectares of the marsh is planned to occur by 2008, with the goal to reduce freshwater vegetation in favor of salt marsh species. We determined if timing restoration projects to coincide with natural germination cycles or seasonal conditions of high salinity would be disadvantageous to P. australis or J. acutus germination. Germination trials lasted 25 days under two temperature range treatments (l0–25 and 15–30°C) and a salinity gradient (0–30 ppt). Many P. australis seeds commenced decomposition after three days (up to 58%). Increased salinity lowered germination in all species; however, only P. austr...

Macrobenthic community assemblage diversity and abundance were monitored on both Cowan and Berowra Creeks in the estuarine reaches of the Hawkesbury River, Sydney Australia during 1997-1998. Natural sediment physicochemical differences were assessed, along with low-level anthropogenic contaminants including copper, lead, zinc, phosphorus and nitrogen. Contaminant levels at all sites were below sediment guideline values for biological effects. Natural physicochemical sediment differences were the main determinants in species assemblage patterns among sites. Three groupings of sites with similar assemblages were observed during February 1998. Berowra Creek sites, which were higher in organic content and silt/clay (and thus metals and nutrients), higher in pH and lower in salinity, were similar in terms of contributions by the polychaetes Ceratoneresis aequisetis, Scoloplos normalis, the isopod Cyathura hakea and the bivalve mollusc Soletellina alba. Sites on upper Cowan Creek, higher in organic content, silt/clay (nutrients and metals) and lower in salinity, were similar and separated from other sites in terms of the polychaete Carazziella victoriensis and the gastropod mollusc Nassarius jonasii. Sites lower in Cowan Creek, tended to be higher in sand content, more saline and lower in organic content and thus nutrient and metal concentrations. These sites were similar in terms of contributions of the polychaete Sigalion bandaensis and the bivalve molluscs, Mysella vitrea and Tellina deltoidalis. The biotic assemblage patterns were not maintained temporally, suggesting the importance of monitoring over time to assess possible future impacts. Aggregating species data to the family level resulted in similar site discrimination. Site differences were less distinct at higher taxonomic levels and suggests future monitoring at the family level is sufficient to detect assemblage differences among sites. The results obtained represent the difficulty in detecting responses to low-level contamination at the community level, and provide a sound anticipatory baseline for the assessment of future possible anthropogenic disturbance in the Hawkesbury River.