National Biosolids Research Program

Michael Warne, Mike McLaughli

The use of biosolids in Australian agriculture – influence of research and future developments

Biosolids (i.e. the treated solid waste stream from sewage treatment plants) were disposed of in Australia to either land-fill sites or the ocean. Four factors have led to the majority of Australian biosolids now being applied to agricultural land: (a) the previous waste practices are no longer acceptable, (b) the drive by Australian governments to re-use wastes, (c) Australian soils are generally deficient in nutrients and (d) biosolids are relatively rich in nutrients. However, biosolids contain a diverse range of contaminants and pathogens. In order to prevent potential negative impacts on human and ecosystem health, guidelines have been developed at both the state and national level in Australia. The concentration of pathogens, nutrients and a suite of contaminants (mainly metals and organochlorine pesticides) control the potential uses of the biosolids that range from unrestricted to being only suitable for land-fill. The current regulatory approach of biosolids will be presented in detail. The applicability of the biosolids guidelines for contaminants to Australian soils was questioned as the majority of the data used to derive the guidelines were from the Northern Hemisphere and a single numerical limit for each contaminant was applied to all Australian soils. In response, the Australian National Biosolids Research Program (NBRP) was established in 2002. The program consisted of 17 field sites in many of the major agricultural regions of Australia and the effects of biosolids, cadmium (Cd), copper (Cu) and zinc (Zn) metal salts to agricultural crops, soil microbial health and soil physicochemical properties were measured for three or four cropping cycles. The results determined the relative biological availability of the metals when added to soil as metal salts or in biosolids and ultimately permitted the derivation of guidelines for Cd, Cu and Zn that vary with the physicochemical properties of the soil (reflecting the biological availability of the metals in the soil). Other metal contaminants in Australian biosolids are not considered to pose a significant hazard to humans or ecosystems and thus attention has now changed to organic contaminants. Research is currently examining the concentration, environmental persistence and impacts of persistent organic pollutants (e.g. dioxins, furans, polybrominated diphenyl ethers), pharmaceuticals and personal care products (e.g. triclosan, 4-nonylphenol, estrone) in biosolids. How the results of this research are being incorporated into regulatory and management systems for biosolids will be discussed

Benthic macroinvertebrate assemblages in remediated wetlands around Sydney, Australia

To investigate potential high organisational level impacts of persistent organic pollution in the wetlands in the Sydney Olympic Park (SOP) remediated site, the benthic macroinvertebrate assemblages of seven wetlands within SOP and two off-site reference wetlands were examined. Sediment cores were collected, stained and preserved from each study site and the macroinvertebrates identified to the appropriate taxonomic level (Class, Order, Family, Subfamily). Data were analysed for taxon richness and macroinvertebrate abundance and multivariate techniques were used to identify chemical/physical characteristics of the sediment, which were important influences on the differences in the assemblage between study sites. Macroinvertebrate abundance was highly variable between study sites and taxon richness was low across all sites. Oligochaetes, nematodes, ostracods and chironomids were the most common taxa found and were the most important in influencing differences between the macroinvertebrate assemblages among the study sites.Sediment grain size and chemical characteristics of the sediments (ΣPAH, ΣPCB, TCDDeq and heavy metal concentrations) were important in separating the study sites based on taxon richness and abundance. Canonical correspondence analysis separated the macroinvertebrate assemblages at newly two created wetlands from those at other study sites including the urban reference sites. Increased sediment POP contamination (particularly as measured TCDDeq and ΣDDT concentrations) is a likely contributor in excluding pollution sensitive taxa and, therefore, alterations to benthic macroinvertebrate assemblages. Further, the influence of TOC suggests the significance of catchment inputs in contributing to changes in macroinvertebrate assemblage. The SOP remediation led to the establishment of wetlands with benthic communities representative of those expected in urban wetlands

Enhanced infection prophylaxis reduces mortality in severely immunosuppressed HIV-infected adults and older children initiating antiretroviral therapy in Kenya, Malawi, Uganda and Zimbabwe: the REALITY trial

Meeting abstract FRAB0101LB from 21st International AIDS Conference 18–22 July 2016, Durban, South Africa. Introduction: Mortality from infections is high in the first 6 months of antiretroviral therapy (ART) among HIV‐infected adults and children with advanced disease in sub‐Saharan Africa. Whether an enhanced package of infection prophylaxis at ART initiation would reduce mortality is unknown. Methods: The REALITY 2×2×2 factorial open‐label trial (ISRCTN43622374) randomized ART‐naïve HIV‐infected adults and children >5 years with CD4 <100 cells/mm3. This randomization compared initiating ART with enhanced prophylaxis (continuous cotrimoxazole plus 12 weeks isoniazid/pyridoxine (anti‐tuberculosis) and fluconazole (anti‐cryptococcal/candida), 5 days azithromycin (anti‐bacterial/protozoal) and single‐dose albendazole (anti‐helminth)), versus standard‐of‐care cotrimoxazole. Isoniazid/pyridoxine/cotrimoxazole was formulated as a scored fixed‐dose combination. Two other randomizations investigated 12‐week adjunctive raltegravir or supplementary food. The primary endpoint was 24‐week mortality. Results: 1805 eligible adults (n = 1733; 96.0%) and children/adolescents (n = 72; 4.0%) (median 36 years; 53.2% male) were randomized to enhanced (n = 906) or standard prophylaxis (n = 899) and followed for 48 weeks (3.8% loss‐to‐follow‐up). Median baseline CD4 was 36 cells/mm3 (IQR: 16–62) but 47.3% were WHO Stage 1/2. 80 (8.9%) enhanced versus 108(12.2%) standard prophylaxis died before 24 weeks (adjusted hazard ratio (aHR) = 0.73 (95% CI: 0.54–0.97) p = 0.03; Figure 1) and 98(11.0%) versus 127(14.4%) respectively died before 48 weeks (aHR = 0.75 (0.58–0.98) p = 0.04), with no evidence of interaction with the two other randomizations (p > 0.8). Enhanced prophylaxis significantly reduced incidence of tuberculosis (p = 0.02), cryptococcal disease (p = 0.01), oral/oesophageal candidiasis (p = 0.02), deaths of unknown cause (p = 0.02) and (marginally) hospitalisations (p = 0.06) but not presumed severe bacterial infections (p = 0.38). Serious and grade 4 adverse events were marginally less common with enhanced prophylaxis (p = 0.06). CD4 increases and VL suppression were similar between groups (p > 0.2). Conclusions: Enhanced infection prophylaxis at ART initiation reduces early mortality by 25% among HIV‐infected adults and children with advanced disease. The pill burden did not adversely affect VL suppression. Policy makers should consider adopting and implementing this low‐cost broad infection prevention package which could save 3.3 lives for every 100 individuals treated