http://wgbis.ces.iisc.ernet.in/energy/stc/biomonitoring_of_wetlands/biomonitoring_aquatic_ecosystem.pdf

Biomonitoring: An appealing tool for assessment of metal pollution in the aquatic ecosystem

http://stopptt.com/wp-content/uploads/2013/12/32bfe50e457fb45a03.pdf

Chemical use in salmon aquaculture: A review of current practices and possible environmental effects

The slope of the simple linear regression between log10 transformed mercury (Hg) concentration and stable nitrogen isotope values (δ15N), hereafter called trophic magnification slope (TMS), from several trophic levels in a food web can represent the overall degree of Hg biomagnification. We compiled data from 69 studies that determined total Hg (THg) or methyl Hg (MeHg) TMS values in 205 aquatic food webs worldwide. Hg TMS values were compared against physicochemical and biological factors hypothesized to affect Hg biomagnification in aquatic systems. Food webs ranged across 1.7 ± 0.7 (mean ± SD) and 1.8 ± 0.8 trophic levels (calculated using δ15N from baseline to top predator) for THg and MeHg, respectively. The average trophic level (based on δ15N) of the upper-trophic-level organisms in the food web was 3.7 ± 0.8 and 3.8 ± 0.8 for THg and MeHg food webs, respectively. For MeHg, the mean TMS value was 0.24 ± 0.08 but varied from 0.08 to 0.53 and was, on average, 1.5 times higher than that for THg with a...

/pdf/biomagnification-of-mercury-in-aquatic-food-webs-a-worldwide-17pko47h22.pdf

Biomagnification of Mercury in Aquatic Food Webs: A Worldwide Meta-Analysis

http://www.pebblescience.org/Pebble-Mine/acid-drainage-pdfs/MetalsRiskAssessmentEPA07.pdf

Framework for metals risk assessment.

A new gold-nanoparticle (AuNP)-based sensor for detecting Hg(II) ions in aqueous solution has been developed. Rhodamine B (RB) molecules that are highly fluorescent in bulk solution fluoresce weakly when they are adsorbed onto AuNP surfaces as a result of fluorescence resonance energy transfer and collision with AuNPs. In the presence of metal ions such as Hg(II), RB molecules are released from the AuNP surface and thus restore the florescence of RB. The modulation of the photoluminescence quenching efficiency of RB−AuNPs in the presence of Hg(II) ions can achieve a large turn-on fluorescence enhancement (400-fold) in aqueous solution, and the entire detection takes less than 10 min. We have improved the selectivity of the probe further by modifying the AuNP surfaces with thiol ligands (mercaptopropionic acid, mercaptosuccinic acid, and homocystine) and adding a chelating ligand (2,6-pyridinedicarboxylic acid) to the sample solutions. Under the optimum conditions, the selectivity of this system for Hg(II)...

/pdf/selective-gold-nanoparticle-based-turn-on-fluorescent-vh98orb2cw.pdf

Selective Gold-Nanoparticle-Based “Turn-On” Fluorescent Sensors for Detection of Mercury(II) in Aqueous Solution

Lake Victoria, East Africa, has been the site of many recent studies measuring mercury (Hg) concentrations in water, fish, sediment, soil, and humans. Most of these studies were motivated by concerns about Hg contamination from processing of gold ore on the southern shores. Total Hg (THg) concentrations in fish were usually below permissible World Health Organization (WHO) concentrations and international marketing limits and do not threaten the lucrative export industry. Nile perch 3–10 kg and most >10 kg had THg concentrations above the WHO threshold concentrations for at-risk groups (200 ng/g). Elevated THg concentrations in large Nile perch are not of major concern because Nile perch are rarely consumed by the people living on Lake Victoria and very large Nile perch are becoming increasingly rare in catches. Water THg concentrations were below Canadian drinking water guidelines but were elevated relative to those in the northern Great Lakes. Sediment and soil THg concentrations were within international guidelines and are comparable to those in northern latitudes but are lower than those in the Amazon basin. Biomass burnings and soil erosion are estimated to be the major sources of THg for the lake and probably constitute a larger source of THg than gold mining in Tanzania. THg concentrations in urine and hair from human volunteers indicate that while gold miners and frequent skin-bleaching cream users are at risk of inorganic mercury poisoning, the rest of the population, including fishermen, is not. Human exposure assessments demonstrated that fish consumption and soil geophagy constitute major sources of THg for humans, but the total estimated daily intake of THg was below the Health Canada tolerable daily intake (TDI) limits. The use of beauty creams containing high inorganic Hg concentrations, however, caused the estimated THg exposure to exceed the TDI. The high THg content in the hair of regular cream users supports this assessment. The nutritional benefits of fish and soil geophagy outweigh the risk of THg poisoning. Still, due to the importance of those natural items as a THg source to humans, as well as the changing nature of Lake Victoria, regular monitoring and risk assessments need to be carried out in the Lake Victoria catchment.

https://ap.smu.ca/~lcampbel/CampbelletalJETH2003.pdf

A review of mercury in Lake Victoria, East Africa: implications for human and ecosystem health.

https://ap.smu.ca/~lcampbel/Campbell_STOTEN2008.pdf

Mercury biomagnification in the food web of Lake Tanganyika (Tanzania, East Africa).

Re-evaluation of metal bioaccumulation and chronic toxicity in Hyalella azteca using saturation curves and the biotic ligand model

Chronic toxicity of arsenic, cobalt, chromium and manganese to Hyalella azteca in relation to exposure and bioaccumulation.

Total mercury concentrations (THg) were
measured in fish from Thruston Bay, Napoleon Gulf in northern Lake Victoria
between 1998 and 2000. Total Hg concentrations in Lates niloticus (Nile
perch) and Oreochromis niloticus (Nile tilapia) ranged from 10.6 to
77.5ng g –1 and from 15.0 to 44.5ng g –1 wet weight
respectively. These concentrations are lower than in the same fish species from
elsewhere in Napoleon Gulf and are in the middle of the range of THg
concentrations from across Lake Victoria. The rate of THg biomagnification, as
indicated by the regression slope of log-THg vs stable nitrogen isotope values
(0.28), is within the ranges of biomagnification rates observed in temperate
and tropical lakes, suggesting that THg is biomagnifying at a similar rate in
Thruston Bay as elsewhere. The low THg concentrations in fish were attributed
to the storage capacity, high oxygen concentrations and high organic matter
content of the wetlands surrounding Thruston Bay. However, caution is required
because the storage capacity and the methylation rates present in the wetlands
of Thruston Bay are unknown and the gradual accumulation of THg contamination
from other sources (e.g. atmospheric THg) may result in unexpected THg
increases in the biota of this system. 
African Journal of Aquatic Science
2004, 29(1): 91–96

https://ap.smu.ca/~lcampbel/CampbelletalAJAS2004.pdf

D.G. Dixon

Papers

A review of mercury in Lake Victoria, East Africa: implications for human and ecosystem health.

Mercury biomagnification in the food web of Lake Tanganyika (Tanzania, East Africa).

Re-evaluation of metal bioaccumulation and chronic toxicity in Hyalella azteca using saturation curves and the biotic ligand model

Chronic toxicity of arsenic, cobalt, chromium and manganese to Hyalella azteca in relation to exposure and bioaccumulation.

Biomagnification of mercury in fish from Thruston Bay, Napoleon Gulf, Lake Victoria (East Africa)