SEGH Articles

SEGH2019 Prize Winners Series: Amy Sansby

05 August 2019
Amy Sansby, a veterinary student at the University of Nottingham, won the best overall ECR poster prize and shares a more detailed account of her study with us!

Aquaculture is the fastest-growing livestock sector globally. Between 1961 and 2016 the average increase in global fish consumption was 3.2%, which exceeded the consumption of meat from all terrestrial animals combined (2.8%).  Aquaculture samples can be used to provide a relatively cheap protein source in many countries and is especially important in developing countries where other protein sources may not be available or affordable. Aquaculture also provides income to developing countries, such as Kenya, where 2,500,000 people are employed both directly and indirectly. It can also provide an income too low skilled members of the community who may otherwise not have an income. Therefore, it is important that this sector grows in a safe and sustainable manner in order to ensure that the food is both safe and nutritionally beneficial to all consumers.

Whilst in many countries the use of antibiotics for growth promotion or metaphylaxis is banned, these practices are still occurring in aquaculture. This can lead to an increase in antimicrobial-resistant populations of bacteria, and additionally elevated levels of antimicrobial residues within the food. Other routes to antibiotic exposure include contamination of water with pharmaceutical products; wastewater runoff from humans; and bad agricultural practices.

This study was part of a larger collaborative effort aiming to assess how a range of pollutants, including antibiotics and heavy metals, affect aquaculture samples that are intended for human consumption. The aim was to evaluate the quality of aquaculture produce from Kenya (a growing country within the aquaculture sector) and Vietnam (a large exporter to several European countries, including the UK). Kenyan aquaculture samples were obtained directly from multiple sites around Lake Victoria, and Vietnamese aquaculture samples were purchased in the UK from major supermarkets. This allowed a comparison to be made between aquaculture samples from both countries.

 

Tilapia sampling in Kenya

 

To evaluate antibiotic residues within the fish, a Premi-test 25 kit was used. This test uses a thermophilic bacteria (Bacillus stearothermophilus) which is susceptible to the following antimicrobial compounds: β-lactams, Cephalosporins, Macrolides, Tetracyclines, Sulphonamides, Aminoglycosides, Quinolones, Amphenicoles and Polypeptides. A positive result indicates a residue level above the EU maximum residue level (MRL). Antibiotic resistance was evaluated using polymerase chain reactions (PCR) which amplifies specific genetic elements, if present. The resistance genes for Tetracycline and Ampicillin were examined in this study.

Extracting fish muscle juice for Premi-test 25 on the boat while sampling in Kenya

 

76% of Kenyan samples and 55% of Vietnamese samples tested positive for antibiotic residues. Genetic elements for Tetracycline resistance were present in fish samples from both counties, and all Kenyan fish tested positive for Ampicillin resistance. This highlights the need for further research to investigate the source of the residues and resistance elements, and also the importance of working with aquaculture farmers in order to reduce contamination of their products.

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Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Health risks and source identification of dietary exposure to indicator polychlorinated biphenyls (PCBs) in Lanzhou, China 2019-09-19

    Abstract

    Polychlorinated biphenyls (PCBs) are widely present in multiple environmental media even long after the phaseout, posing a health risk to the general population. Dietary intake is the major exposure route of PCBs; however, information is limited regarding PCBs in food that people directly consume. This study aims to measure personal exposure to indicator PCBs, evaluate the health risks, and identify their sources in a typical metropolitan city in China. Multi-day food samples were collected from 21 subjects in Lanzhou, Gansu Province, in two seasons using the duplicate plate method. Samples were extracted and analyzed for seven indicator PCBs using gas chromatography/mass spectrometry. Average daily doses (ADDs) of ∑7PCBs were estimated using Monte Carlo analysis with food intake information. Results show that PCB-118 and PCB-180 were the major congeners in food samples with average concentrations of 1.42 and 1.11 ng/g, respectively. The average (± SD) ADD of ∑7PCBs was 26.47 ± 22.10 ng/kg day among adults aged 18–69 years and displayed small variation across age groups. Comparing with the chronic RfD of 7 ng/kg day, 67% of people had their ADDs exceeding this threshold. The median cancer risk was 5.52 × 10−5, and 51% of residents had risks exceeding the action level of 10−4. The principal component analysis identified waste incineration, gasoline engine production, and leakage of #1 PCBs as the major PCBs sources. In conclusion, a large portion of Lanzhou residents has high non-cancer and cancer risks from dietary exposure to PCBs, which warrants control actions targeting these major sources.

  • Comprehensive assessment of heavy metals pollution of farmland soil and crops in Jilin Province 2019-09-18

    Abstract

    As a major agricultural province in China, it is necessary to study the content of heavy metals in farmland soil and crop in Jilin Province and to evaluate the risks to ecology and human health. This study presented the work completed on 79 soil samples, 10 rice samples, 66 maize samples and 15 soybean samples collected from Jilin Province farmland and evaluated six heavy metals (Zn, Cu, Pb, Cd, Hg and As) concentrations. The results showed that the concentrations of the six heavy metals in farmland soil and crop samples from Jilin Province basically met the soil standards and food health standards of China. The agricultural soil pollution spatial distribution was the most serious in the south of Jilin Province and the lightest in the west. The non-carcinogenic risks faced by children eating crops were higher than those of adults, but the carcinogenic risks were lower than those of adults. Both of the two health risks to adults and children from eating crops were very limited. The results would help determine the heavy metals pollution in farmland soil in Jilin Province efficiently and accurately and helped decision makers to achieve a balance between production and environmental regulation.

  • Sustainability of agricultural and wild cereals to aerotechnogenic exposure 2019-09-14

    Abstract

    In recent decades, the problem of the constantly increasin level of anthropogenic load on the environment is becoming more and more acute. Some of the most dangerous pollutants entering the environment from industrial emissions are heavy metals. These pollutants are not susceptible to biodegradation over time, which leads to their accumulation in the environment in dangerous concentrations. The purpose of this work is to study the sustainability of cultivated and wild plants of the Poaceae family to aerotechnogenic pollution in the soil. The content of heavy metals in couch grass (Elytrigia repens (L.) Nevski), meadow bluegrass (Poa pratensis L.) and soft wheat (Triticum aestivum) plants grown in the impact zone of Novocherkassk Power Station has been analyzed. Contamination of cultivated and wild cereals with Pb, Zn, Ni and Cd has been established. It has been shown that the accumulation of heavy metals is individual for each plant species. An average and close correlation have been established between the total HM content and the content of their mobile forms in the soil and their content in plants. For the plants studied, the translocation factor (TF) and the distribution coefficient (DC) of HM have been calculated. The TF is formed by the ratio of the concentration of an element in the root plant dry weight to the content of its mobile compounds in the soil. The DC value makes it possible to estimate the capacity of the aboveground parts of plants to absorb and accumulate elements under soil pollution conditions and is determined as the ratio of the metal content in the aboveground biomass to its concentration in the roots. TF and DC values have shown a significant accumulation of elements by plants from the soil, as well as their translocation from the root system to the aboveground part. It has been revealed that even within the same Poaceae family, cultural species are more sensitive to man-made pollution than wild-growing ones.