The role of a yellow-legged gull (Larus michahellis) small colony in conveying trace elements (As, Cd, Cr, Cu, Ni, Pb, THg, V, Zn) was assessed in a Mediterranean nature reserve (Marinello ponds) at various spatial and temporal scales. Trace element concentrations in guano were high and seasonally variable. In contrast, contamination in the ponds was not influenced by season but showed strong spatial variability among ponds, according to the different guano input. Biogenic enrichment factor B confirmed the role of gulls in the release of trace elements through guano subsidies. In addition, comparing trace element pond concentrations to the US NOAA’s SQGs, As, Cu and Ni showed contamination levels associated with possible negative biological effects. Thus, this study reflects the need to take seabirds into account as key factors influencing ecological processes and contamination levels even in remote areas, especially around the Mediterranean, where these birds are abundant but overlooked.

Land use in east China tends to change from paddy rice to vegetables or other high-value cash crops, resulting in high input rates of organic manures and increased risk of contamination with both heavy metals (HMs) and antibiotics. This investigation was conducted to determine the accumulation, distribution and risks of HMs and tetracyclines (TCs) in surface soils and profiles receiving different amounts of farmyard manure. Soil samples collected from suburbs of Hangzhou city, Zhejiang province were introduced to represent three types of land use change from paddy rice to asparagus production, vineyards and field mustard cultivation, and divided into two portions, one of which was air-dried and sieved through 2-, 0.3- and 0.149-mm nylon mesh for determination of pH and heavy metals. The other portion was frozen at -20 °C, freeze-dried and sieved through a 0.3-mm nylon mesh for tetracyline determination. HM and TC concentrations in surface soils of 14-year-old mustard fields were the highest with total Cu, Zn, Cd and ∑TCs of 50.5, 196, 1.03 mg kg(-1) and 22.9 μg kg(-1), respectively, on average. The total Cu sequence was field mustard > vineyards > asparagus when duration of land use change was considered; oxytetracycline (OTC) and doxycycline were dominant in soils used for asparagus production; OTC was dominant in vineyards and chlortetracycline (CTC) was dominant in mustard soils. There were positive pollution relationships among Cu, Zn and ∑TCs, especially between Cu and Zn or Cu and ∑TCs. Repeated and excessive application of manures from intensive farming systems may produce combined contamination with HMs and TCs which were found in the top 20 cm of the arable soil profiles and also extended to 20-40 cm depth. Increasing manure application rate and cultivation time led to continuing increases in residue concentrations and movement down the soil profile.

Aquatic birds are often used as a health indicator of the marine ecosystem. African penguins living in the zoo make good research material as they form a link between the marine and the terrestrial ecosystem in terms of xenobiotic circulation. Tests were performed on whole herring—the food of the penguins—as well as on bird muscle, liver, brain, eggs, feathers and guano in order to determine total mercury, aldrin, dieldrin, endrin, isodrin, endosulfan isomers, endosulfan sulfate, methoxychlor, dichlorodiphenyltrichloroethane (DDT) and its metabolites. In herring and penguin, the tests did not show the presence of β-endosulfan, endosulfan sulfate, aldrin and isodrin. It was shown that penguins absorb about 36.8 μg of organochlorine pesticides and 4.6 μg of mercury with their food on a daily basis. Xenobiotics accumulate mostly in the liver, from where they are transported to the muscles and the brain, where the highest bioaccumulation factor is reached by endrin and pp’-DDT. Conceivably, the older the penguin, the higher is the concentration level of pesticides in its liver and brain. Molting was found to be the most effective way of eliminating mercury, dieldrin and methoxychlor from the system. Insecticides, such as DDT and its metabolites, were removed most effectively by females through laying of eggs. The standard four eggs laid within a year may have contained up to 20 % of the total amount of pesticides which had been absorbed with food, but no more than 5 % of mercury.

Selected arsenic-volatilizing indigenous soil bacteria were isolated and their ability to form volatile arsenicals from toxic inorganic arsenic was assessed. Approximately 37 % of AsIII (under aerobic conditions) and 30 % AsV (under anaerobic conditions) were volatilized by new bacterial isolates in 3 days. In contrast to genetically modified organism, indigenous soil bacteria was capable of removing 16 % of arsenic from contaminated soil during 60 days incubation period while applied with a low-cost organic nutrient supplement (farm yard manure).