حوار مستقل
نطاق التركيز الجغرافي:
الصين, المملكة المتحدة لبريطانيا العظمى وآيرلندا الشمالية
Discussion topic outcome
Potential risks and mitigation measures Both the UK and China have considerable expertise in understanding the risks associated with use of organic fertilisers in sustainable agricultural systems. There is a longstanding research programme in China on the risks associated with wastewater derived fertilizers, from field sites in Nanjing and Ningbo. Hazards include the introduction of inorganic contaminants (e.g. metals), organic chemicals, including emerging contaminants (e.g. pharmaceuticals and personal care products), as well the presence of pathogens (e.g. bacteria, viruses). Use of organic
... قراءة المزيد fertilisers can also introduce antimicrobial genes (ARGs) into the agricultural environment. ARGs can enter the food system via uptake into crops but can also damage soil structure by altering the soil microbial community and breaking the soil microaggregates held together by microbial activity. There is a need to both reduce the ARG load in fertilizer manufacturing, and to research how mitigation options can limit the risk of ARGs associated with wastewater derived fertilizers. We need to consider the legacy of existing contaminants and emerging contaminants as these both present a risk to ecosystem and human health e.g. heavy metals are often high in concentration and do not degrade whereas organic contaminants such as antibiotics are low in concentration but still remain bioactive and cause selection pressure on antibiotic resistance genes. Our research has shown that the build-up of Cd and Pb from waste products has resulted in impacts on soil health and the reduction in crop yield. It is important to consider these to achieve food goals as well as retain soil health. It is also critical to consider the effects of transformation products and not just the parent contaminants. Often these transformation products contain bioactive properties and still can influence soil health and organisms present within the environmental matrices. We also need to consider the influence of mixtures of contaminants. We know very little about how chemicals can interact, especially inorganic-organic chemical combinations. This is largely due to the difficulties in addressing mixture effects as well as detections of complex samples. We therefore need to advance our experimental and analytical capabilities to deal with this challenge. Mitigation measures exist which focus on reducing the concentration of contaminants in organic fertiliser through advanced treatment technologies such as anaerobic digestion, liquid-solid separation, and electrolysis. The extraction of struvite is the most advanced commercial operation globally. There is a need to address regional challenges when considering mitigation options as in some cases enhanced waste treatment is not an option when a country has limited sewage connectivity and sanitation options. In this case, bioremediation options may be more appropriate such as pollutant removal via wetlands or composting of faecal sludge from pit latrines. Research in China has evaluated the potential of biochar to become a suitable sustainable method in removing contaminants from environmental matrices. More research is needed to understand currently overlooked issues such as the potential for contaminants to desorb and release slowly into the environment, ecotoxicology (earthworms mortality rate with high biochar %) and the bioavailability of contaminants adsorbed to biochars. In order to overcome potential risks we need to integrate research and industry application and have integrated planning to move forwards. While we could focus on developing sustainable, low cost technology to remove contaminants from the waste stream; perhaps we should stop focusing on adding new processes and innovation to selectively capture an ever-increasing list of contaminants. Instead, focus should be on upstream causes of this contamination, ask why they are present in the waste stream and how we can rectify this. The focus should be placed on the risks of NOT making change (business as usual), rather than focusing solely on the risks of doing something ('least worst'). This allows a more balanced decision going forward. قراءة القليل
مسار (مسارات) العمل: 1, 3
الكلمات الأساسية: Environment and Climate, Policy, Trade-offs